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Sample records for compounds xvi calorimetric

  1. Thermochemistry of uranium compounds: XVI, Calorimetric determination of the standard molar enthalpy of formation at 298.15 K, low-temperature heat capacity, and high-temperature enthalpy increments of UO{sub 2}(OH){sub 2} {center_dot} H{sub 2}O (schoepite)

    SciTech Connect

    Tasker, I.R.; O`Hare, P.A.G.; Lewis, B.M.; Johnson, G.K.; Cordfunke, E.H.P.

    1987-08-01

    Three precise calorimetric methods, viz., low-temperature adiabatic, high-temperatuare drop, and solution-reaction, have been used to determine as a function of temperature the key chemical thermodynamic properties of a pure sample of schoepite, UO{sub 2}(OH){sub 2} {center_dot} H{sub 2}O. The following results have been obtained at the standard reference temperature T = 298.15 K:standard molar enthalpy of formation {Delta}/sub f/H/sub m/{sup 0}(T) = {minus}1825.4 +- 2.1 kJ mol/sup {minus}1/; molar heat capacity C/sub p,m/{sup 0}(T) = 172.07 +- 0.34 JK/sup {minus}1/; and the standard molar entropy S/sub m/{sup 0}(T) = 188.54 +- 0.38 JK/sup {minus}1/ mol/sup {minus}1/. The molar enthalpy increments relative to 298.15 K and the molar heat capacity are given by the polynomials: {H{sub m}{sup 0}(T) {minus} H{sub m}{sup 0}(298.15 K)}/(J mol/sup {minus}1/) = {minus}38209.0 + 84.2375 (T/K) + 0.1472958 (T/K){sup 2} and C/sub p,m/{sup 0}(T)/(JK/sup {minus}1/ mol/sup {minus}1/) = 84.238 + 0.294592 (T/K), where 298.15 K < T < 400 K. The present result for {Delta}/sup f/H/sub m/{sup 0} at 298.15 K has been combined with three other closely-agreeing values from the literature to give a recommended weighted mean {Delta}/sub f/H/sub m/{sup 0} = {minus}1826.4 +- 1.7 kJ mol/sup {minus}1/, from which is calculated the standard Gibbs energy of formation {Delta}/sub f/G/sub m/{sup 0} = {minus}1637.0 +- 1.7 kJ mol/sup {minus}1/ at 298.15 K. Complete thermodynamic properties of schoepite are tabulated from 298.15 to 423.15 K. 19 refs., 6 tabs.

  2. Synthesis, calorimetric, structural and conductivity studies in a new thallium selenate tellurate adduct compound

    SciTech Connect

    Ktari, L.; Abdelhedi, M.; Bouhlel, N.; Dammak, M.; Cousson, A.

    2009-08-05

    The crystal structure of the thallium selenate tellurate Tl{sub 2}SeO{sub 4}.Te(OH){sub 6} (TlSeTe) was determined by X-ray diffraction method. The title compound crystallizes in the monoclinic system with P2{sub 1}/c space group. The following parameters are: a = 12.358(3) A; b = 7.231(1) A; c = 11.986(2) A; {beta} = 111.092(2){sup o}; Z = 4. The structure can be regarded as being built of isolated TeO{sub 6} octahedra and SeO{sub 4} tetrahedra. The Tl{sup +} cations are intercalated between these kinds of polyhedra. The main feature of this structure is the coexistence of two different and independent anions (SeO{sub 4}{sup 2-} and TeO{sub 6}{sup 6-}) in the same unit cell. The structure is stable due to O-H...O hydrogen bonds which link tetrahedral and octahedral groups. Crystals of Tl{sub 2}SeO{sub 4}.Te(OH){sub 6} undergo three endothermal transitions at 373, 395 and 437 K. These transitions are detected by DSC and analyzed by dielectric measurements with impedance spectroscopy. The evolution of conductivity versus temperature showed the presence of a protonic conduction phase transition at 437 K. The phase transition at 373 K can be related to a structural phase transition, whereas the one at 395 K is ascribed as likely due to a ferroelectric-paraelectric phase transition.

  3. Calorimetric study and modeling of molecular mobility in amorphous organic pharmaceutical compounds using a modified Adam-Gibbs approach.

    PubMed

    Mao, Chen; Chamarthy, Sai Prasanth; Pinal, Rodolfo

    2007-11-22

    The purpose of this study is to provide a quantitative characterization of the thermal behavior of amorphous organic pharmaceutical compounds across their glass transition temperature, and to assess their molecular mobility as a function of temperature and time by combining theoretical simulations with experimental measurements using differential scanning calorimetry. A computational approach built on the Boltzmann superposition principle of nonexponential decay and the Adam-Gibbs theory of entropic-dependent structural relaxation is presented. The heat capacities of the crystalline and amorphous forms are incorporated into the simulation in order to accurately assess the entropic fictive temperature as functions of temperature and time under any arbitrary set of experimental conditions. Using this method, we evaluated properties of the glass former, D and T0, and the nonexponentiality index beta, for amorphous salicin, felodipine, and nifedipine, by fitting the simulated glass transition profile with the experimentally determined heat capacity across the glass transition region. From this fit, the evolution of the relaxation time of the model compounds following any thermal cycle, including heating, cooling, and isothermal holds can then be estimated a priori. This study reveals the profound and inextricable effect of thermal history on the molecular mobility of the amorphous materials, and the ability of the glass to undergo fast changes in its molecular motions over an aging process even at low temperatures. PMID:17967007

  4. Device for calorimetric measurement

    DOEpatents

    King, William P; Lee, Jungchul

    2015-01-13

    In one aspect, provided herein is a single crystal silicon microcalorimeter, for example useful for high temperature operation and long-term stability of calorimetric measurements. Microcalorimeters described herein include microcalorimeter embodiments having a suspended structure and comprising single crystal silicon. Also provided herein are methods for making calorimetric measurements, for example, on small quantities of materials or for determining the energy content of combustible material having an unknown composition.

  5. Prototype of calorimetric flow microsensor

    NASA Astrophysics Data System (ADS)

    Sazhin, Oleg

    2012-11-01

    An analytical model of calorimetric flow sensor has been developed. The results of the application of this model are utilized to develop a calorimetric flow microsensor with optimal functional characteristics. The technology to manufacture the microsensor is described. A prototype of the microsensor suitable to be used in the mass air flow meter has been designed. The basic characteristics of the microsensor are presented.

  6. Calorimetric gas sensor

    DOEpatents

    Ricco, A.J.; Hughes, R.C.; Smith, J.H.; Moreno, D.J.; Manginell, R.P.; Senturia, S.D.; Huber, R.J.

    1998-11-10

    A combustible gas sensor is described that uses a resistively heated, noble metal-coated, micromachined polycrystalline Si filament to calorimetrically detect the presence and concentration of combustible gases. The filaments tested to date are 2 {micro}m thick {times} 10{micro}m wide {times} 100, 250, 500, or 1000 {micro}m-long polycrystalline Si; some are overcoated with a 0.25 {micro}m-thick protective CVD Si{sub 3}N{sub 4} layer. A thin catalytic Pt film was deposited by CVD from the precursor Pt(acac){sub 2} onto microfilaments resistively heated to approximately 500 C; Pt deposits only on the hot filament. Using a constant-resistance-mode feedback circuit, Pt-coated filaments operating at ca. 300 C (35 mW input power) respond linearly, in terms of the change in supply current required to maintain constant resistance (temperature), to H{sub 2} concentrations between 100 ppm and 1% in an 80/20 N{sub 2}/O{sub 2} mixture. Other catalytic materials can also be used. 11 figs.

  7. Calorimetric gas sensor

    DOEpatents

    Ricco, Antonio J.; Hughes, Robert C.; Smith, James H.; Moreno, Daniel J.; Manginell, Ronald P.; Senturia, Stephen D.; Huber, Robert J.

    1998-01-01

    A combustible gas sensor that uses a resistively heated, noble metal-coated, micromachined polycrystalline Si filament to calorimetrically detect the presence and concentration of combustible gases. The filaments tested to date are 2 .mu.m thick.times.10 .mu.m wide.times.100, 250, 500, or 1000 .mu.m-long polycrystalline Si; some are overcoated with a 0.25 .mu.m-thick protective CVD Si.sub.3 N.sub.4 layer. A thin catalytic Pt film was deposited by CVD from the precursor Pt(acac).sub.2 onto microfilaments resistively heated to approximately 500.degree. C.; Pt deposits only on the hot filament. Using a constant-resistance-mode feedback circuit, Pt-coated filaments operating at ca. 300.degree. C. (35 mW input power) respond linearly, in terms of the change in supply current required to maintain constant resistance (temperature), to H.sub.2 concentrations between 100 ppm and 1% in an 80/20 N.sub.2 /O.sub.2 mixture. Other catalytic materials can also be used.

  8. PREFACE: Symmetries in Science XVI

    NASA Astrophysics Data System (ADS)

    2014-10-01

    This volume of the proceedings ''Symmetries in Science XVI'' is dedicated to the memory of Miguel Lorente and Allan Solomon who both participated several times in these Symposia. We lost not only two great scientists and colleagues, but also two wonderful persons of high esteem whom we will always remember. Dieter Schuch, Michael Ramek There is a German saying ''all good things come in threes'' and ''Symmetries in Science XVI'', convened July 20-26, 2013 at the Mehrerau Monastery, was our third in the sequel of these symposia since taking it over from founder Bruno Gruber who instigated it in 1988 (then in Lochau). Not only the time seemed to have been perfect (one week of beautiful sunshine), but also the medley of participants could hardly have been better. This time, 34 scientists from 16 countries (more than half outside the European Union) came together to report and discuss their latest results in various fields of science, all related to symmetries. The now customary grouping of renowned experts and talented newcomers was very rewarding and stimulating for all. The informal, yet intense, discussions at ''Gasthof Lamm'' occurred (progressively later) each evening till well after midnight and finally till almost daybreak! However, prior to the opening ceremony and during the conference, respectively, we were informed that Miguel Lorente and Allan Solomon had recently passed away. Both attended the SIS Symposia several times and had many friends among present and former participants. Professor Peter Kramer, himself a long-standing participant and whose 80th birthday commemoration prevented him from attending SIS XVI, kindly agreed to write the obituary for Miguel Lorente. Professors Richard Kerner and Carol Penson (both also former attendees) penned, at very short notice, the tribute to Allan Solomon. The obituaries are included in these Proceedings and further tributes have been posted to our conference website. In 28 lectures and an evening poster-session, topics ranging from theoretical chemistry and molecular physics via fundamental problems in quantum theory to thermodynamics, nonlinear dynamics, soliton theory and finally cosmology, were examined and lively discussed. Nearly all the talks can also be viewed on the conference website. The majority of participants contributed to these Proceedings but some were unable to do so as their results were either previously submitted or published elsewhere. We refer to: · Quesne C 2013, J. Math. Phys. 54, 102102. · Spera M 2013, (Nankai Series in Pure, Applied Mathematics and Theoretical Physics): 11 Symmetries and Groups in Contemporary Physics: pp. 593-598 Proceedings of the XXIX International Colloquium on Group-Theoretical Methods in Physics Tianjin, China, 20 - 26 August 2012 (World Scientific, Singapore) · Snobl L and Winternitz P 2014, Classification and Identification of Lie Algebras, CRM Monograph Series 33 (Montreal) ISBN-10: 0-8218-4355-9, ISBN-13: 978-0-8218-4355-0 (http://www.ams.org/bookstore?fn=20&arg1=crmmseries&ikey=CRMM-33). Our personal thanks to Daniel and family! Endless support from the Schenk Family who, among other things, sponsored (yet again) the entire conference dinner (including wines and banquet hall) meant that some costs could be alleviated. We could therefore assist various colleagues from economically-weak countries, despite the lack of external funding. A financial deficit meant we would have had to forego the Conference Proceedings, published in previous years by IOP. After long deliberations, and with donations from Gerhard Berssenbrügge, Dr. Dr. Stephan Hauk and Dr. Volker Weisswange, this could be facilitated. We are very grateful to these private donors for their generous and wholehearted support. The staff of Collegium Mehrerau is also to be thanked for their hospitality. Finally, our sincere thanks to Yvette not only for her preparatory work and support during the conference, but also for her persistent interest and help in producing the Proceedings within a reasonable time. Dieter Schuch, Frankfurt am Main, Germany Michael Ramek, Graz, Austria August 2014

  9. Thermal Analysis of Calorimetric Systems

    NASA Astrophysics Data System (ADS)

    D'Aulerio, L.; Violante, V.; Castagna, E.; Fiore, R.; Capobianco, L.; Del Prete, Pr.; Tanzella, F.; McKubre, M.

    Calorimetric analysis has been carried out for both electrochemical and gas loading experiment. A finite element modeling for steady state and transient gave a satisfactory agreement with the experimental results. For electrochemical cells modeling was applied for isoperibolic and flow calorimeters with the main goal to optimize the system. For high-temperature gas loading experiments the modeling was applied to translate the temperature field (steady state and transient three-dimensional analysis), then, in such a case calculations allowed to perform the calorimetry. This experiment was a replication of the MATRIX experiment performed at SRI by some of the authors.1,2 A correlation between 4He production and excess of power during gas loading of deuterium in palladium was observed. Excess of power was estimated by means of the temperature measurements and by comparing experimental data with both the calibration data and the modeling results. Also the effect of the room temperature evolution was considered in the mathematical model of the experiment. 4He tights stainless steel cell have been filled first with a Pd-based catalyst then loaded with deuterium or hydrogen (blank). After filling cells with gas we observed a different thermal behavior of the cells C1 and C2 containing deuterium, compared to the cell C4 containing hydrogen. The temperature increasing in cells C1 and C2 was estimated to be produced by an additional power source of 0.1 W. The measured excess of helium was consistent with expected value obtained by assuming that the excess of energy was produced by a D+D reaction giving 4He+heat (24 MeV). The slope of the temperature increasing was larger in cells C1 and C2, and after achieving a stationary condition for the system the temperature of cells C1 and C2 increased again. During the thermal effect an analysis of the gas was done for the cells C1 and C2. An increasing of the helium content was revealed for both the cells. The He concentration increased up to a factor larger than 2 in both cells C1 and C2.

  10. Calorimetric thermobarometry of experimentally shocked quartz

    NASA Technical Reports Server (NTRS)

    Ocker, Katherine D.; Gooding, James L.; Hoerz, Friedrich

    1994-01-01

    Structural damage in experimentally shock-metamorphosed, granular quartz is quantitatively measurable by differential scanning calorimetry (DSC). Shock-induced loss of crystallinity is witnessed by disappearance of the alpha/beta phase transformation and evolution of a broad endoenthalpic strain peak at 650-900 K. The strain-energy peak grows rapidly at less than 10 GPa but declines with increasing shock pressure; it approaches zero at 32 GPa where vitrification is extensive. Effects of grain size and post-shock thermal history must be better understood before calorimetric thermobarometry of naturally shocked samples becomes possible.

  11. Fast Electron Thermometry for Ultrasensitive Calorimetric Detection

    NASA Astrophysics Data System (ADS)

    Gasparinetti, S.; Viisanen, K. L.; Saira, O.-P.; Faivre, T.; Arzeo, M.; Meschke, M.; Pekola, J. P.

    2015-01-01

    We demonstrate radio-frequency thermometry on a micrometer-sized metallic island below 100 mK. Our device is based on a normal-metal-insulator-superconductor tunnel junction coupled to a resonator with transmission readout. In the first generation of the device, we achieve 90 μ K /√{Hz } noise-equivalent temperature with 10 MHz bandwidth. We measure the thermal relaxation time of the electron gas in the island, which we find to be of the order of 100 μ s . Such a calorimetric detector, upon optimization, can be seamlessly integrated into superconducting circuits, with immediate applications in quantum-thermodynamics experiments down to single quanta of energy.

  12. Ultra-Responsive Thermal Sensors for the Detection of Explosives Using Calorimetric Spectroscopy (CalSpec)

    SciTech Connect

    Datskos, P.G.; Datskou, I.; Marlar, T.A.; Rajic, S.

    1999-04-05

    We have developed a novel chemical detection technique based on infrared micro-calorimetric spectroscopy that can be used to identify the presence of trace amounts of very low vapor pressure target compounds. Unlike numerous recently developed low-cost sensor approaches, the selectivity is derived from the unique differential temperature spectrum and does not require the questionable reliability of highly selective coatings to achieve the required specificity. This is accomplished by obtaining the infrared micro-calorimetric absorption spectrum of a small number of molecules absorbed on the surface of a thermal detector after illumination through a scanning monochromator. We have obtained infrared micro-calorimetric spectra for explosives such as TNT over the wavelength region 2.5 to 14.5 Mu-m. Thus both sophisticated and relatively crude explosive compounds and components are detectable with these ultra-sensitive thermal-mechanical micro-structures. In addition to the above mentioned spectroscopy technique and associated data, the development of these advanced thermal detectors is also presented in detail.

  13. 25 CFR 36.43 - Standard XVI-Student activities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... CFR 31.7. All student activity accounts shall be audited annually. (h) The school shall provide for... 25 Indians 1 2010-04-01 2010-04-01 false Standard XVI-Student activities. 36.43 Section 36.43 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR EDUCATION MINIMUM ACADEMIC STANDARDS FOR...

  14. Electronic Nose for Recognition of Volatile Vapor Mixtures Using a Nanopore-Enhanced Opto-Calorimetric Spectroscopy.

    PubMed

    Chae, Inseok; Lee, Dongkyu; Kim, Seonghwan; Thundat, Thomas

    2015-07-21

    An electronic nose (e-nose) for identification and quantification of volatile organic compounds (VOCs) vapor mixtures was developed using nanopore-enhanced opto-calorimetric spectroscopy. Opto-calorimetric spectroscopy based on specific molecular vibrational transitions in the mid infrared (IR) "molecular fingerprint" regime allows highly selective detection of VOCs vapor mixtures. Nanoporous anodic aluminum oxide (AAO) microcantilevers, fabricated using a two-step anodization and simple photolithography process, were utilized as highly sensitive thermomechanical sensors for opto-calorimetric signal transduction. The AAO microcantilevers were optimized by fine-tuning AAO nanopore diameter in order to enhance their thermomechanical sensitivity as well as their surface area. The thermomechanical sensitivity of a bilayer AAO microcantilever with a 60 nm pore diameter was approximately 1 μm/K, which is far superior to that of a bilayer plain silicon (Si) microcantilever. The adsorbed molecules of VOCs mixtures on the AAO microcantilever were fully recognized and quantified by variations of peak positions and amplitudes in the opto-calorimetric IR spectra as well as by shifts in the resonance frequency of the AAO microcantilever with the adsorbed molecules. Furthermore, identification of complex organic compounds with a real industrial sample was demonstrated by this e-nose system. PMID:26111073

  15. Calorimetric and calorimetric-fluorimetric methods for the measurement of singlet oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Ikonnikov, V. K.; Sirotin, S. A.; Kharchenko, S. S.; Lacour, B.; Puech, V.

    2007-05-01

    Considered is the method of isothermal calorimeter intended for the measurement of singlet oxygen (SO) concentrations in oxygen flow. The method is distinguished for its simplicity and does not require expensive equipment. However, by now no calculation methods were available that would grant the necessary properties of the calorimeter at designed conditions. In this our work such calculation method is developed for calorimeters. Compared are the concentrations of SO produced in electric discharge generators as measured by calorimetric and optical methods.

  16. Radiation beam calorimetric power measurement system

    DOEpatents

    Baker, John; Collins, Leland F.; Kuklo, Thomas C.; Micali, James V.

    1992-01-01

    A radiation beam calorimetric power measurement system for measuring the average power of a beam such as a laser beam, including a calorimeter configured to operate over a wide range of coolant flow rates and being cooled by continuously flowing coolant for absorbing light from a laser beam to convert the laser beam energy into heat. The system further includes a flow meter for measuring the coolant flow in the calorimeter and a pair of thermistors for measuring the temperature difference between the coolant inputs and outputs to the calorimeter. The system also includes a microprocessor for processing the measured coolant flow rate and the measured temperature difference to determine the average power of the laser beam.

  17. Calorimetric sensors for energy deposition measurements

    SciTech Connect

    Langenbrunner, J.; Cooper, R.; Morgan, G.

    1998-12-31

    A calorimetric sensor with several novel design features has been developed. These sensors will provide an accurate sampling of thermal power density and energy deposition from proton beams incident on target components of accelerator-based systems, such as the Accelerator Production of Tritium Project (APT) and the Spallation Neutron Source (SNS). A small, solid slug (volume = 0.347 cc) of target material is suspended by kevlar fibers and surrounded by an adiabatic enclosure in an insulating vacuum canister of stainless steel construction. The slug is in thermal contact with a low-mass, calibrated, 100-k{Omega} thermistor. Power deposition caused by the passage of radiation through the slug is calculated from the rate of temperature rise of the slug. The authors have chosen slugs composed of Pb, Al, and LiAl.

  18. New calorimetric all-particle energy spectrum

    NASA Technical Reports Server (NTRS)

    Linsley, J.

    1985-01-01

    Both the maximum size N sub m and the sea level muon size N sub mu have been used separately to find the all-particle energy spectrum in the air shower domain. However the conversion required, whether from N sub m to E or from N sub mu to E, has customarily been carried out by means of calculations based on an assumed cascase model. It is shown here that by combining present data on N sub m and N sub mu spectra with data on: (1); the energy spectrum of air shower muons and (2) the average width of the electron profile, one can obtain empirical values of the N sub m to E and N sub mu to E conversion factors, and an empirical calorimetric all-particle spectrum, in the energy range 2 x 10 to the 6th power E 2 x 10 to the 9th power GeV.

  19. Anomalous thermodynamic properties of ice XVI and metastable hydrates

    NASA Astrophysics Data System (ADS)

    Yagasaki, Takuma; Matsumoto, Masakazu; Tanaka, Hideki

    2016-02-01

    A new ice polymorph, called ice XVI, has recently been discovered experimentally by extracting the guest molecules from Ne hydrate. The ice and its filled form (clathrate hydrate) have a unique network topology which results in several interesting properties. Here we provide a theoretical method to calculate thermodynamic properties of a semiopen system in equilibrium with guest gas and thus occupancy of the guest can be varied with temperature and pressure. Experimental observations such as the disappearance of negative thermal expansivity and contraction of the host lattice upon encaging guest molecules are well reproduced, and those behaviors are elucidated in terms of the free energy of cage occupation and its temperature and pressure dependence. We propose an application of the method for preparing ice XVI to create metastable clathrate hydrates having intriguing properties with much lower occupancy of guest molecules than that at equilibrium, which otherwise cannot form.

  20. EDITORIAL: Special issue: CAMOP MOLEC XVI

    NASA Astrophysics Data System (ADS)

    Ascenzi, Daniela; Franceschi, Pietro; Tosi, Paolo

    2007-09-01

    In this special issue of CAMOP/Physica Scripta we would like to present a picture of the state-of-the-art in the field of the dynamics of molecular systems. It contains a collection of papers submitted in association with the most recent MOLEC meeting (MOLEC XVI), which was held in September 2006 in Levico Terme (Italy) to celebrate the 30th anniversary of the MOLEC conference series. The series of biennial European Conferences on the Dynamics of Molecular Systems (MOLEC) started in 1976, when the first meeting was held in Trento (Italy). Successive conferences were organized in Brandbjerg Højskole (Denmark, 1978), Oxford (UK, 1980), Nijmegen (The Netherlands, 1982), Jerusalem (Israel, 1984), Aussois (France, 1986), Assisi (Italy, 1988), Bernkastel-Kues (Germany, 1990), Prague (Czech Republic, 1992), Salamanca (Spain, 1994), Nyborg Strand (Denmark, 1996), Bristol (UK, 1998), Jerusalem (Israel, 2000), Istanbul (Turkey, 2002) and Nunspeet (The Netherlands, 2004). This is the second time that Physica Scripta has hosted a special issue dedicated to MOLEC. The previous issue ( Physica Scripta (2006) 73 C1-C89) was edited by Steven Stolte and Harold Linnartz following the MOLEC 2004 conference. Following the philosophy of CAMOP, we have asked invited speakers to summarize important problems in their research area, with the objective of setting forth the current thinking of leading researchers in atomic, molecular and optical physics. This comprises discussions of open questions, important new applications, new theoretical and experimental approaches and also predictions of where the field is heading. In addition to being authoritative contributions of acknowledged experts, we hope that the papers also appeal to non-specialists as each work contains a clear and broad introduction and references to the accessible literature. The present special issue comprises 17 papers, which are arranged according to the following topics: theoretical and experimental studies of molecular collisions and chemically reactive systems (papers by Toennies, Cavalli et al, Varandas, Nyman, Allan et al, Liu et al, Boxford et al); cooling and alignment of molecular systems (papers by Kumarappan et al, van de Meerakker et al); photon-matter interactions, spectroscopy and photodissociation (papers by Fárník and Buck, Golan et al, Borghesani et al, Coreno et al); theory of complex systems (papers by Villarreal et al, Bodo et al, Yurtsever and Calvo). The final contribution concerns the dynamics of systems of biological relevance (paper by Denicke et al). The paper by Toennies, one of the founding fathers of the MOLEC conference and winner of the MOLEC award in 1996, presents a comprehensive account of the experimental developments in the field of low energy collisions over the last 30 years, and provides a short outlook on how the most recent cooling and ultra cooling techniques (helium droplets and electro-magnetic laser traps) could open up new perspectives in the field of chemical reaction dynamics. Cavalli et al present a theoretical interpretation of overlapping resonances in the reactive cross section for the benchmark reaction F + H2→HF + H, explained by the formation of a short-lived state located in the transition state region and of a van der Waals metastable state in the exit valley. The subject of accurate ab initio calculations for potential energy surfaces is addressed by Varandas in a paper describing suitable modelling strategies to obtain intermolecular potentials at near spectroscopic resolution. In the following paper, Nyman gives an overview of how thermal rate constants for polyatomic chemical reactions can be calculated from first principles: the reaction H2 + CH3→CH4 + H is used as an example and theoretical results are compared with experimental ones. The `uncharted territory' of collision dynamics at the gas-liquid interface is explored in the pioneering contribution by Allan et al, in which experimental results on the reactivity of O atoms with long chain liquid hydrocarbons are interpreted with the aid of molecular dynamics calculations. The contribution of Liu et al shifts towards the reactivity of charged systems, by presenting results of crossed beam experiments on the reaction dynamics of ethylene with OD+ and D2O+ ions. Boxford et al continue with an experimental and theoretical study of the systematics of multiply-charged anion fragmentation in dianion-cation contact ion pairs. The next two contributions present the latest findings in the field of cooling and alignment of molecular systems. Kumarappan et al provide an overview of adiabatic and non-adiabatic laser-induced alignment of linear and asymmetric top molecules. van de Meerakker and Meijer discuss the state-of-the-art of Stark deceleration of OH radicals and the prospects for future applications of such tools in scattering experiments are presented. The third section of this issue comprises spectroscopy and photodissociation studies. Fárník and Buck discuss the photodissociation of HBr molecules in three different cluster environments: pure hydrogen bonded (HBr)n clusters, large van der Waals bonded HBr.Arn and HBr.(H2O)n clusters. Differences in the photofragmentation of rovibrationally excited methylamine and propyne molecules are taken as an example by Golan et al to demonstrate the importance of vibrationally mediated photodissociation for understanding energy flows in molecular systems. A study of the IR luminescence in excited and weakly bound rare gas complexes is reported in the contribution by Borghesani et al. Coreno et al discuss the generation of core hole states by soft x-ray absorption of molecules by presenting results on the visible and UV fluorescence decay from H2O, NH3 and CH4 molecules following core electron excitation and by proposing a mechanism of molecular dissociation. The fourth section includes three theoretical contributions. In the first one, by Villarreal et al, the simulation of IR spectra of molecules solvated in atomic clusters is reviewed by presenting a method to obtain energies and wave functions for systems composed of a molecular impurity immersed in He clusters. Bodo et al continue with an application of variational and diffusion Monte Carlo calculation procedure to the `solvation' of molecular and atomic ions in small He clusters. Yurtsever and Calvo describe the influence of a central point defect on the structure of 2D clusters consisting of point charge particles that are confined by an isotropic trap. Finally, Denicke et al review the imaging technique of single-beam and multi-beam two-photon laser-scanning microscopy for biomedical research by showing applications to the study of cell metabolism via NADH imaging. We are grateful to all the authors who participated with their contributions to this issue. We thank Physica Scripta for providing us with a platform for the publication of the MOLEC special issue and we hope that such a recently established tradition will continue to bring to readers new insights into the advances in the field of molecular dynamics.

  1. Nanowell-patterned TiO{sub 2} microcantilevers for calorimetric chemical sensing

    SciTech Connect

    Lee, Dongkyu Chae, Inseok; Thundat, Thomas; Kim, Seonghwan; Jeon, Sangmin

    2014-04-07

    A sensitive calorimetric sensor using a TiO{sub 2} microcantilever with nanowells patterned on one of its sides is described. This single material cantilever is sensitive to temperature change without relying on the metal deposition-based bimetallic effect. The thermomechanical sensitivity originates from the structure dependent variations in both the elastic modulus and thermal expansion coefficient due to the presence of ordered nanowells. These cantilever beams offer an alternate and efficient chemical sensing route for vapor phase analytes using photothermal spectroscopy. Selective and sensitive detection of organophosphorus compounds, as well as their photocatalytic decomposition under ultraviolet light exposure are demonstrated.

  2. Calorimetric study of peroxycarboxylic ester synthesis.

    PubMed

    Fritzsche, L; Knorr, A

    2009-04-30

    Exothermic reactions involving organic peroxides carry a high potential hazard and must be considered with care. A safe handling requires, among others, the assessment of thermal process safety, for which safety characteristics like overall heat production and the resulting adiabatic temperature rise are essential. The article presents the results of the calorimetric investigation of the synthesis of four peroxycarboxylic esters, three tert-Butyl and one tert-Amyl peroxycarboxylic ester. In the two-step synthesis the second one clearly shows the higher exothermic potential. The overall heat production lies in the range of 126-135 kJ/mol and is nearly independent of the carboxylic acid residual in the tert-Butyl peroxycarboxylic ester. The calculated adiabatic temperature rise is 70-80K. Influence of temperature and feed rate on the heat generation is discussed for one species. A grading of the synthesis with respect to temperature levels according to the criticality classes by Stoessel leads to the most critical for an exothermic reaction. PMID:18722058

  3. Sensitivity and systematics of calorimetric neutrino mass experiments

    SciTech Connect

    Nucciotti, A.; Cremonesi, O.; Ferri, E.

    2009-12-16

    A large calorimetric neutrino mass experiment using thermal detectors is expected to play a crucial role in the challenge for directly assessing the neutrino mass. We discuss and compare here two approaches for the estimation of the experimental sensitivity of such an experiment. The first method uses an analytic formulation and allows to obtain readily a close estimate over a wide range of experimental configurations. The second method is based on a Montecarlo technique and is more precise and reliable. The Montecarlo approach is then exploited to study some sources of systematic uncertainties peculiar to calorimetric experiments. Finally, the tools are applied to investigate the optimal experimental configuration of the MARE project.

  4. Calorimetric evaluation of selective surfaces in a vacuum

    SciTech Connect

    Duff, W.S.; Hodgson, D.

    1999-07-01

    The properties of selective absorber coatings are calorimetrically evaluated in situ in evacuated solar collector tubes. This paper provides the details of the testing and evaluation procedures and presents preliminary results of the current round of testing that is now beginning.

  5. Thermodynamic properties by non-calorimetric methods. Progress report, August 1, 1988--July 31, 1989

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Collier, W.B.; Strube, M.M. |

    1989-12-31

    This three year research program provides a valuable complement to the experimental programs currently in progress at NIPER for the Advanced Research and Technology Development (AR and TD) and Advanced Exploration and Process Technology (AEPT) divisions of the Department of Energy. These experimental programs are focused on the calorimetric determination of thermodynamic properties of key polynuclear heteroatom-containing aromatic molecules. This project for the Office of Energy Research focuses on the non-calorimetric determination of thermodynamic properties through the extension of existing correlation methodologies and through molecular spectroscopy with statistical mechanics. The paper discusses progress in three areas: (1) Improvement of thermochemical and thermophysical property predictions via enhancement of group-contribution methods using two approaches, namely, development and improvement of group-contribution parameters via correlations involving the expanded modern thermodynamics data base and development of group-contribution parameters via molecular spectroscopy and statistical mechanics of key monocyclic organic compounds; (2) Molecular spectroscopy and statistical mechanics: equipment development and developments in interpretation and assignment of spectra; and (3) Thermophysical property correlations.

  6. Acyclic diterpene glycosides, capsianosides VIII, IX, X, XIII, XV and XVI from the fruits of Paprika Capsicum annuum L. var. grossum BAILEY and Jalapeño Capsicum annuum L. var. annuum.

    PubMed

    Lee, Jong-Hyun; Kiyota, Naoko; Ikeda, Tsuyoshi; Nohara, Toshihiro

    2006-10-01

    Paprika and Jalapeño are used as vegetables and spices. We have obtained six new acyclic diterpene glycosides, called capsianosides XIII (2), XV (3), IX (4), XVI (5), X (6) and VIII (7) together with known capsianoside II (1) from the fruits of the Paprika and Jalapeño. The structures of these compounds have been elucidated by the (1)H- and (13)C-NMR spectra and two-dimensional NMR methods. PMID:17015971

  7. Micro-calorimetric sensor for trace explosive particle detection

    NASA Astrophysics Data System (ADS)

    Olsen, Jesper K.; Greve, Anders; Privorotskaya, N.; Senesac, L.; Thundat, T.; King, W. P.; Boisen, A.

    2010-04-01

    A micro differential thermal analysis (DTA) system is used for detection of trace explosive particles. The DTA system consists of two silicon micro chips with integrated heaters and temperature sensors. One chip is used for reference and one for the measurement sample. The sensor is constructed as a small silicon nitride bridge incorporating heater elements and a temperature measurement resistor. In this manuscript the DTA system is described and tested by measuring calorimetric response of DNT (2,4-Dinitrotoluene). The design of the senor is described and the temperature uniformity investigated using finite element modelings and Raman temperature measurements. The functionality is tested using two different kinds of explosive deposition techniques and calorimetric responses are obtained. Under the framework of the Xsense project at the Technical University of Denmark (DTU) which combines four independent sensing techniques, these micro DNT sensors will be included in handheld explosives detectors with applications in homeland security and landmine clearance.

  8. Calorimetric Power Measurements of the DIII-D Gyrotron System

    NASA Astrophysics Data System (ADS)

    Gorelov, I.; Lohr, J.; Callis, R. W.; Cary, W. P.; Ponce, D.; Pinsker, R. I.; Chiu, H.; Baity, F. W.

    2001-10-01

    Gyrotron power measurements are an integral part of rf experiments on DIII-D. The ECH complex at General Atomics is built up from four 110 GHz, 1 MW gyrotrons, one from Communication and Power Industry (CPI) and three from Russia's Gyrotron Company (Gycom). Power measurements are made calorimetrically using the temperature and flow measurements of the gyrotron cooling circuits. Three such circuits are measured on the Gycom gyrotrons: window, MOU and dummy load. Interior cooling circuits are additionally measured on the CPI gyrotron that are very useful when tuning for maximum power and efficiency. Calorimetric signals from each cooling circuit are acquired by computer, where the dissipated energy is calculated with a LabView program. From these calculations, total rf power and efficiency were determined. Thus, calorimetry measurements were effectuated during gyrotron operations to provide the average power of each pulse.

  9. PIXE analysis of Italian ink drawings of the XVI century

    NASA Astrophysics Data System (ADS)

    Zucchiatti, A.; Climent-Font, A.; Enguita, O.; Fernandez-Jimenez, M. T.; Finaldi, G.; Garrido, C.; Matillas, J. M.

    2005-10-01

    The composition of inks in a group of 24 drawings of ten XVI century Italian painters, has been determined by PIXE at the external micro-beam line of the Centro de Micro Análisis de Materiales of the Universidad Autónoma de Madrid. Ink elemental thicknesses have been determined by comparison with a set of certified thin standards. A comprehensive comparison of inks has also been performed by renormalisation of spectra and definition of an ink-to-ink distance. The elemental compositions and the ink-to-ink distances give consistent results that are generally in line with the appearance of the drawings and add relevant instrumental information to the stylistic observation, revealing for example the presence of retouches and additions in different parts of a drawing. Cluster analysis performed on a subgroup of 13 artefacts from the Genoese painter Luca Cambiaso and his school has revealed a partition that separates neatly the work of the master from that of his followers.

  10. 20 CFR 408.930 - Are title II and title XVI benefits subject to adjustment to recover title VIII overpayments?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Underpayments and Overpayments Adjustment of Title II Benefits § 408.930 Are title II and title XVI benefits subject to adjustment to... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Are title II and title XVI benefits...

  11. 20 CFR 408.930 - Are title II and title XVI benefits subject to adjustment to recover title VIII overpayments?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Underpayments and Overpayments Adjustment of Title II Benefits § 408.930 Are title II and title XVI benefits subject to adjustment to... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Are title II and title XVI benefits...

  12. 20 CFR 408.930 - Are title II and title XVI benefits subject to adjustment to recover title VIII overpayments?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Underpayments and Overpayments Adjustment of Title II Benefits § 408.930 Are title II and title XVI benefits subject to adjustment to... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Are title II and title XVI benefits...

  13. 20 CFR 408.930 - Are title II and title XVI benefits subject to adjustment to recover title VIII overpayments?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Underpayments and Overpayments Adjustment of Title II Benefits § 408.930 Are title II and title XVI benefits subject to adjustment to... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Are title II and title XVI benefits...

  14. 20 CFR 408.930 - Are title II and title XVI benefits subject to adjustment to recover title VIII overpayments?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Underpayments and Overpayments Adjustment of Title II Benefits § 408.930 Are title II and title XVI benefits subject to adjustment to... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Are title II and title XVI benefits...

  15. Formation and properties of ice XVI obtained by emptying a type sII clathrate hydrate.

    PubMed

    Falenty, Andrzej; Hansen, Thomas C; Kuhs, Werner F

    2014-12-11

    Gas hydrates are ice-like solids, in which guest molecules or atoms are trapped inside cages formed within a crystalline host framework (clathrate) of hydrogen-bonded water molecules. They are naturally present in large quantities on the deep ocean floor and as permafrost, can form in and block gas pipelines, and are thought to occur widely on Earth and beyond. A natural point of reference for this large and ubiquitous family of inclusion compounds is the empty hydrate lattice, which is usually regarded as experimentally inaccessible because the guest species stabilize the host framework. However, it has been suggested that sufficiently small guests may be removed to leave behind metastable empty clathrates, and guest-free Si- and Ge-clathrates have indeed been obtained. Here we show that this strategy can also be applied to water-based clathrates: five days of continuous vacuum pumping on small particles of neon hydrate (of structure sII) removes all guests, allowing us to determine the crystal structure, thermal expansivity and limit of metastability of the empty hydrate. It is the seventeenth experimentally established crystalline ice phase, ice XVI according to the current ice nomenclature, has a density of 0.81 grams per cubic centimetre (making it the least dense of all known crystalline water phases) and is expected to be the stable low-temperature phase of water at negative pressures (that is, under tension). We find that the empty hydrate structure exhibits negative thermal expansion below about 55 kelvin, and that it is mechanically more stable and has at low temperatures larger lattice constants than the filled hydrate. These observations attest to the importance of kinetic effects and host-guest interactions in clathrate hydrates, with further characterization of the empty hydrate expected to improve our understanding of the structure, properties and behaviour of these unique materials. PMID:25503235

  16. Formation and properties of ice XVI obtained by emptying a type sII clathrate hydrate

    NASA Astrophysics Data System (ADS)

    Falenty, Andrzej; Hansen, Thomas C.; Kuhs, Werner F.

    2014-12-01

    Gas hydrates are ice-like solids, in which guest molecules or atoms are trapped inside cages formed within a crystalline host framework (clathrate) of hydrogen-bonded water molecules. They are naturally present in large quantities on the deep ocean floor and as permafrost, can form in and block gas pipelines, and are thought to occur widely on Earth and beyond. A natural point of reference for this large and ubiquitous family of inclusion compounds is the empty hydrate lattice, which is usually regarded as experimentally inaccessible because the guest species stabilize the host framework. However, it has been suggested that sufficiently small guests may be removed to leave behind metastable empty clathrates, and guest-free Si- and Ge-clathrates have indeed been obtained. Here we show that this strategy can also be applied to water-based clathrates: five days of continuous vacuum pumping on small particles of neon hydrate (of structure sII) removes all guests, allowing us to determine the crystal structure, thermal expansivity and limit of metastability of the empty hydrate. It is the seventeenth experimentally established crystalline ice phase, ice XVI according to the current ice nomenclature, has a density of 0.81 grams per cubic centimetre (making it the least dense of all known crystalline water phases) and is expected to be the stable low-temperature phase of water at negative pressures (that is, under tension). We find that the empty hydrate structure exhibits negative thermal expansion below about 55 kelvin, and that it is mechanically more stable and has at low temperatures larger lattice constants than the filled hydrate. These observations attest to the importance of kinetic effects and host-guest interactions in clathrate hydrates, with further characterization of the empty hydrate expected to improve our understanding of the structure, properties and behaviour of these unique materials.

  17. Measurement of the calorimetric energy scale in MINOS

    SciTech Connect

    Hartnell, Jeffrey J.

    2005-06-01

    MINOS is a long-baseline neutrino oscillation experiment. A neutrino beam is created at the Fermi National Accelerator Laboratory in Illinois and fired down through the Earth. Measurements of the energy spectra and composition of the neutrino beam are made both at the source using the Near detector and 735 km away at the Soudan Underground Laboratory in Minnesota using the Far detector. By comparing the spectrum and flavour composition of the neutrino beam between the two detectors neutrino oscillations can be observed. Such a comparison depends on the accuracy of the relative calorimetric energy scale. This thesis details a precise measurement of the calorimetric energy scale of the MINOS Far detector and Calibration detector using stopping muons with a new ''track window'' technique. These measurements are used to perform the relative calibration between the two detectors. This calibration has been accomplished to 1.7% in data and to significantly better than 2% in the Monte Carlo simulation, thus achieving the MINOS relative calibration target of 2%. A number of cross-checks have been performed to ensure the robustness of the calorimetric energy scale measurements. At the Calibration detector the test-beam energy between run periods is found to be consistent with the detector response to better than 2% after the relative calibration is applied. The muon energy loss in the MINOS detectors determined from Bethe-Bloch predictions, data and Monte Carlo are compared and understood. To estimate the systematic error on the measurement of the neutrino oscillation parameters caused by a relative miscalibration a study is performed. A 2% relative miscalibration is shown to cause a 0.6% bias in the values of {Delta}m{sup 2} and sin{sup 2}(2{theta}).

  18. The Level-0 calorimetric trigger of the NA62 experiment

    NASA Astrophysics Data System (ADS)

    Ammendola, R.; Barbanera, M.; Bizzarri, M.; Bonaiuto, V.; Ceccucci, A.; Checcucci, B.; De Simone, N.; Fantechi, R.; Federici, L.; Fucci, A.; Lupi, M.; Paoluzzi, G.; Papi, A.; Piccini, M.; Ryjov, V.; Salamon, A.; Salina, G.; Sargeni, F.; Venditti, S.

    2016-02-01

    The NA62 experiment at the CERN SPS aims at measuring the branching ratio of the very rare kaon decay K+ → π+ ν bar nu (expected 10-10) with a 10% background. Since an high-intensity kaon beam is required to collect enough statistics, the Level-0 trigger plays a fundamental role in both the background rejection and in the particle identification. The calorimetric trigger collects data from various calorimeters and it is able to identify clusters of energy deposit and determine their position, fine-time and energy. This paper describes the complete hardware commisioning and the setup of the trigger for the 2015 physics data taking.

  19. Setup for calorimetric measurements at temperatures below 1 K

    NASA Astrophysics Data System (ADS)

    Eropkin, V. N.; Chagovets, T. V.

    2003-11-01

    A compact, top-loading 3He evaporation refrigerator is built for doing heat-capacity studies on various samples at temperatures below 1 K. It uses adsorption pumping and utilizes a portable helium Dewar of the STG-40 type as the cryostat. A calorimetric cell is built which permits investigation of the heat capacity of samples with masses of less than one gram. The lowest measurement temperature is 0.32 K. The dependence of the temperature of the 3He evaporation chamber on the power delivered to it is established. The refrigerator can operate continuously for two hours at a heat load of 50 μW.

  20. Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine/water.

    PubMed

    Cisneros, L O; Rogers, W J; Mannan, M S

    2001-03-19

    Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset temperatures, reaction order, activation energies, pressures of noncondensable products, thermal stability at 100 degrees C, and the effect of HA storage time. Discussed also are the catalytic effects of carbon steel, stainless steel, stainless steel with silica coating, inconel, titanium, and titanium with silica coating on the reaction self-heat rates and onset temperatures. In borosilicate glass cells, HA was relatively stable at temperatures up to 133 degrees C, where the HA decomposition self-heat rate reached 0.05 degrees C/min. The added stabilizers appeared to reduce HA decomposition rates in glass cells and at ambient temperatures. The tested metals and metal surfaces coated with silica acted as catalysts to lower the onset temperatures and increase the self-heat rates. PMID:11165058

  1. ASIC for calorimetric measurements in the astrophysical experiment NUCLEON

    NASA Astrophysics Data System (ADS)

    Atkin, E.; Voronin, A.; Karmanov, D.; Kudryashov, I.; Kovalev, I.; Shumikhin, V.

    2016-02-01

    A satellite with the NUCLEON apparatus was launched in Dec. 2014. The space NUCLEON project of ROSCOSMOS is designed to investigate cosmic ray nuclei energy spectra from 100 GeV to 1000 TeV as well as cosmic ray electron spectra from 20 GeV to 3 TeV. The method of energy determination by means of a silicon instrument for measuring the particle charge of cosmic rays and the calorimetric system were developed. The main parameters, that determine the quality of calorimetric systems are linearity of transfer characteristic and the dynamic range of input signals, which should reach 30 000 MIPs (minimum ionizing particles). The ASIC, satisfying these requirements, consisting of 32 channels with a unique dynamic range from 1 to 40000 MIPs, signal to noise ratio not less than 2.5 at a shaper peaking time of 2 μs and a low power consumption of 1.5 mW/channel has been designed. The first results of the ASIC functionality in space are presented.

  2. Empirical free energy calculation: comparison to calorimetric data.

    PubMed Central

    Weng, Z.; Delisi, C.; Vajda, S.

    1997-01-01

    An effective free energy potential, developed originally for binding free energy calculation, is compared to calorimetric data on protein unfolding, described by a linear combination of changes in polar and nonpolar surface areas. The potential consists of a molecular mechanics energy term calculated for a reference medium (vapor or nonpolar liquid), and empirical terms representing solvation and entropic effects. It is shown that, under suitable conditions, the free energy function agrees well with the calorimetric expression. An additional result of the comparison is an independent estimate of the side-chain entropy loss, which is shown to agree with a structure-based entropy scale. These findings confirm that simple functions can be used to estimate the free energy change in complex systems, and that a binding free energy evaluation model can describe the thermodynamics of protein unfolding correctly. Furthermore, it is shown that folding and binding leave the sum of solute-solute and solute-solvent van der Waals interactions nearly invariant and, due to this invariance, it may be advantageous to use a nonpolar liquid rather than vacuum as the reference medium. PMID:9300497

  3. Novel micro-calorimetric spectroscopy for mine detection

    SciTech Connect

    Datskos, P.G. |; Rajic, S.; Egert, C.M.; Datskou, I.

    1998-03-01

    The authors have developed a novel micro-calorimetric spectroscopy technique that can be used in mine detection applications. In this technique target molecules are allowed to adsorb on the surface of sub-femtojoule sensitive micromechanical thermal detectors. The adsorption of molecules on the thermal detector surface causes a differential surface stress resulting in an initial trigger. By exposing each element in an array of thermal detectors to different photon wavelengths, an extremely sensitive and unique photothermal signature response can be obtained. The authors present their results on target chemicals adsorbed on the detector surface at sub-monolayer coverage levels. They will present infrared photothermal spectra for trace concentrations of diisopropyl methylphosphonate (DIMP), and trinitrotoluene (TNT) over the wavelength region 2.5 to 14.5 microns. They found that in the wavelength region 2.5 to 14.5 microns the photothermal spectra of DIMP and TNT exhibit a number of peaks and are in excellent agreement with infrared absorption spectra found in the literature. Chemical detectors based on micro-calorimetric spectroscopy can be used to sensitively sense small number of molecules adsorbed on a thermal detector surface. The photothermal signature resulting from photon irradiation can be used for improved chemical characterization.

  4. A TEMPORAL MAP IN GEOSTATIONARY ORBIT: THE COVER ETCHING ON THE EchoStar XVI ARTIFACT

    SciTech Connect

    Weisberg, Joel M.; Paglen, Trevor

    2012-10-01

    Geostationary satellites are unique among orbital spacecraft in that they experience no appreciable atmospheric drag. After concluding their respective missions, geostationary spacecraft remain in orbit virtually in perpetuity. As such, they represent some of human civilization's longest lasting artifacts. With this in mind, the EchoStar XVI satellite, to be launched in fall 2012, will play host to a time capsule intended as a message for the deep future. Inspired in part by the Pioneer Plaque and Voyager Golden Records, the EchoStar XVI Artifact is a pair of gold-plated aluminum jackets housing a small silicon disk containing 100 photographs. The Cover Etching, the subject of this paper, is etched onto one of the two jackets. It is a temporal map consisting of a star chart, pulsar timings, and other information describing the epoch from which EchoStar XVI came. The pulsar sample consists of 13 rapidly rotating objects, 5 of which are especially stable, having spin periods <10 ms and extremely small spin-down rates. In this paper, we discuss our approach to the time map etched onto the cover and the scientific data shown on it, and we speculate on the uses that future scientists may have for its data. The other portions of the EchoStar XVI Artifact will be discussed elsewhere.

  5. The ISLANDS Project. I. Andromeda XVI, An Extremely Low Mass Galaxy Not Quenched by Reionization

    NASA Astrophysics Data System (ADS)

    Monelli, Matteo; Martínez-Vázquez, Clara E.; Bernard, Edouard J.; Gallart, Carme; Skillman, Evan D.; Weisz, Daniel R.; Dolphin, Andrew E.; Hidalgo, Sebastian L.; Cole, Andrew A.; Martin, Nicolas F.; Aparicio, Antonio; Cassisi, Santi; Boylan-Kolchin, Michael; Mayer, Lucio; McConnachie, Alan; McQuinn, Kristen B. W.; Navarro, Julio F.

    2016-03-01

    Based on data aquired in 13 orbits of Hubble Space Telescope time, we present a detailed evolutionary history of the M31 dSph satellite Andromeda XVI, including its lifetime star formation history (SFH), the spatial distribution of its stellar populations, and the properties of its variable stars. And XVI is characterized by prolonged star formation activity from the oldest epochs until star formation was quenched ˜6 Gyr ago, and, notably, only half of the mass in stars of And XVI was in place 10 Gyr ago. And XVI appears to be a low-mass galaxy for which the early quenching by either reionization or starburst feedback seems highly unlikely, and thus it is most likely due to an environmental effect (e.g., an interaction), possibly connected to a late infall in the densest regions of the Local Group. Studying the SFH as a function of galactocentric radius, we detect a mild gradient in the SFH: the star formation activity between 6 and 8 Gyr ago is significantly stronger in the central regions than in the external regions, although the quenching age appears to be the same, within 1 Gyr. We also report the discovery of nine RR Lyrae (RRL) stars, eight of which belong to And XVI. The RRL stars allow a new estimate of the distance, (m - M)0 = 23.72 ± 0.09 mag, which is marginally larger than previous estimates based on the tip of the red giant branch. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13028.

  6. Calorimetric determination of the enthalpy of 1-butyl-3-methylimidazolium bromide synthesis: a key quantity in thermodynamics of ionic liquids.

    PubMed

    Paulechka, Yauheni U; Kabo, Andrey G; Blokhin, Andrey V

    2009-11-01

    The enthalpy of the 1-butyl-3-methylimidazolium bromide [C(4)mim]Br ionic liquid synthesis reaction 1-methylimidazole (liq) + 1-bromobutane (liq) --> [C(4)mim]Br (liq) was determined in a homemade small-volume isoperibol calorimeter to be Delta(r)H degrees (298) = -87.7 +/- 1.6 kJ x mol(-1). The activation energy for this reaction in a homogeneous system E(A) = 73 +/- 4 kJ x mol(-1) was found from the results of calorimetric measurements. The formation enthalpies for the crystalline and liquid [C(4)mim]Br were determined from the calorimetric data: Delta(f)H degrees (298)(cr) = -178 +/- 5 kJ x mol(-1) and Delta(f)H degrees (298)(liq) = -158 +/- 5 kJ x mol(-1). The ideal-gas formation enthalpy of this compound Delta(f)H degrees (298)(g) = 16 +/- 7 kJ x mol(-1) was calculated using the methods of quantum chemistry and statistical thermodynamics. The vaporization enthalpy of [C(4)mim]Br, Delta(vap)H degrees (298) = 174 +/- 9 kJ x mol(-1), was estimated from the experimental and calculated formation enthalpies. It was demonstrated that vapor pressure of this ionic liquid cannot be experimentally determined. PMID:19821605

  7. Nanoclay modified polycarbonate blend nanocomposites: Calorimetric and mechanical properties

    NASA Astrophysics Data System (ADS)

    Zicans, Janis; Meri, Remo Merijs; Ivanova, Tatjana; Berzina, Rita; Kalnins, Martins; Maksimovs, Roberts

    2014-05-01

    The research is devoted to characterization of polycarbonate (PC)/acrylonitrile-butadiene styrene (ABS) blend nanocomposites in respects to it mechanical and calorimetric properties. It is shown that PC blend with 10wt% of ABS is more suitable for development of polymer-clay nanocomposites than PC blend with 40wt.% of ABS. It is revealed that the greatest modulus and strength increment is observed for PC/10wt.%ABS blend nanocomposites, containing aromatic organomodifier treated clay (Dellite 43B). It is also determined that optimal nanofiller content for the investigated PC/10%ABS blend is 1.5 wt.%. Increase of mechanical characteristics of PC/10wt.%ABS blend nanocomposites is accompanied with the rise of glass transition temperatures of both polymeric phases, particularly that of PC.

  8. Preparation, structural, and calorimetric characterization of bicomponent metallic photonic crystals

    NASA Astrophysics Data System (ADS)

    Kozlov, M. E.; Murthy, N. S.; Udod, I.; Khayrullin, I. I.; Baughman, R. H.; Zakhidov, A. A.

    2007-03-01

    We report preparation and characterization of novel bicomponent metal-based photonic crystals having submicron three-dimensional (3D) periodicity. Fabricated photonic crystals include SiO2 sphere lattices infiltrated interstitially with metals, carbon inverse lattices filled with metal or metal alloy spheres, Sb inverse lattices, and Sb inverse lattices filled with Bi spheres. Starting from a face centered SiO2 lattice template, these materials were obtained by sequences of either templating and template extraction or templating, template extraction, and retemplating. Surprising high fidelity was obtained for all templating and template extraction steps. Scanning electron microscopy (SEM), small angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) were used to characterize the structure and the effects of the structure on calorimetric properties. To the best of our knowledge, SAXS data on metallic photonic crystals were collected for first time.

  9. Remote calorimetric detection of urea via flow injection analysis.

    PubMed

    Gaddes, David E; Demirel, Melik C; Reeves, W Brian; Tadigadapa, Srinivas

    2015-12-01

    The design and development of a calorimetric biosensing system enabling relatively high throughput sample analysis are reported. The calorimetric biosensor system consists of a thin (∼20 μm) micromachined Y-cut quartz crystal resonator (QCR) as a temperature sensor placed in close proximity to a fluidic chamber packed with an immobilized enzyme. Layer by layer enzyme immobilization of urease is demonstrated and its activity as a function of the number of layers, pH, and time has been evaluated. This configuration enables a sensing system where a transducer element is physically separated from the analyte solution of interest and is thereby free from fouling effects typically associated with biochemical reactions occuring on the sensor surface. The performance of this biosensing system is demonstrated by detection of 1-200 mM urea in phosphate buffer via a flow injection analysis (FIA) technique. Miniaturized fluidic systems were used to provide continuous flow through a reaction column. Under this configuration the biosensor has an ultimate resolution of less than 1 mM urea and showed a linear response between 0-50 mM. This work demonstrates a sensing modality in which the sensor itself is not fouled or contaminated by the solution of interest and the enzyme immobilized Kapton® fluidic reaction column can be used as a disposable cartridge. Such a system enables reuse and reliability for long term sampling measurements. Based on this concept a biosensing system is envisioned which can perform rapid measurements to detect biomarkers such as glucose, creatinine, cholesterol, urea and lactate in urine and blood continuously over extended periods of time. PMID:26479269

  10. Calorimetric studies of the ammonia-water system with application to the outer solar system

    NASA Astrophysics Data System (ADS)

    Yarger, J.; Lunine, J. I.; Burke, M.

    1993-07-01

    A series of heating experiments was performed on the condensed ammonia-water system using a differential scanning calorimeter (DSC). The water-rich samples were cooled quickly to below 130 K, then heated at a variety of rates. Rather than a single peritectic melt at 176 K, expected for the equilibrium system of water ice and ammonia dihydrate, four enthalpic transitions were repeatedly seen in the temperature range 150-176 K. These transitions are generally consistent with the earlier calorimetric results of Van Kasteren (1973), who interpreted the lowest temperature exotherm as crystallization of an amorphous ammonia-water compound formed during cooling. We propose that both sets of experiments are seeing the crystallization of ammonia monohydrate, which is metastable relative to the dihydrate, followed by partial remelting and crystallization of dihydrate upon further heating. The apparent stability of the monohydrate in the dihydrate equilibrium field implies a potentially complex behavior of ammonia-water ices in satellites. Possible self-heating of the mixture by several tens of degrees up to the 170 K eutectic could make mobilization of ammonia-water liquids in icy satellite interiors energetically easier than previously thought.

  11. Calorimetric studies of the ammonia-water system with application to the outer solar system

    NASA Technical Reports Server (NTRS)

    Yarger, Jeffery; Lunine, Jonathan I.; Burke, Michael

    1993-01-01

    A series of heating experiments was performed on the condensed ammonia-water system using a differential scanning calorimeter (DSC). The water-rich samples were cooled quickly to below 130 K, then heated at a variety of rates. Rather than a single peritectic melt at 176 K, expected for the equilibrium system of water ice and ammonia dihydrate, four enthalpic transitions were repeatedly seen in the temperature range 150-176 K. These transitions are generally consistent with the earlier calorimetric results of Van Kasteren (1973), who interpreted the lowest temperature exotherm as crystallization of an amorphous ammonia-water compound formed during cooling. We propose that both sets of experiments are seeing the crystallization of ammonia monohydrate, which is metastable relative to the dihydrate, followed by partial remelting and crystallization of dihydrate upon further heating. The apparent stability of the monohydrate in the dihydrate equilibrium field implies a potentially complex behavior of ammonia-water ices in satellites. Possible self-heating of the mixture by several tens of degrees up to the 170 K eutectic could make mobilization of ammonia-water liquids in icy satellite interiors energetically easier than previously thought.

  12. Relativistic close-coupling calculation of photoionization and photorecombination of Fe XVI

    SciTech Connect

    Chen Guoxin

    2008-02-15

    Large-scale relativistic close-coupling calculation of photoionization and photorecombination of Fe XVI reveal strong resonance structures at low energies. The Breit-Pauli R-matrix method was employed in the calculations with the inclusion of 89 spectroscopic states in the close-coupling eigenfunction expansion. Our unified photorecombination cross sections show significant differences from previous results. The Gaussian averaged effective photorecombination cross sections to the 2p{sup 6}3d{sub 3/2,5/2} states of Fe XVI are shown to be 24% larger than those used for normalization by Brown et al. [Phys. Rev. Lett. 96, 253201 (2006)]. This result should help resolve the issue raised in Brown's paper on the puzzling large discrepancy between theoretical and experimental electron impact excitation cross sections of Fe XVII.

  13. Genomic analysis of the blood attributed to Louis XVI (1754–1793), king of France

    PubMed Central

    Olalde, Iñigo; Sánchez-Quinto, Federico; Datta, Debayan; Marigorta, Urko M.; Chiang, Charleston W. K.; Rodríguez, Juan Antonio; Fernández-Callejo, Marcos; González, Irene; Montfort, Magda; Matas-Lalueza, Laura; Civit, Sergi; Luiselli, Donata; Charlier, Philippe; Pettener, Davide; Ramírez, Oscar; Navarro, Arcadi; Himmelbauer, Heinz; Marquès-Bonet, Tomàs; Lalueza-Fox, Carles

    2014-01-01

    A pyrographically decorated gourd, dated to the French Revolution period, has been alleged to contain a handkerchief dipped into the blood of the French king Louis XVI (1754–1793) after his beheading but recent analyses of living males from two Bourbon branches cast doubts on its authenticity. We sequenced the complete genome of the DNA contained in the gourd at low coverage (~2.5×) with coding sequences enriched at a higher ~7.3× coverage. We found that the ancestry of the gourd's genome does not seem compatible with Louis XVI's known ancestry. From a functional perspective, we did not find an excess of alleles contributing to height despite being described as the tallest person in Court. In addition, the eye colour prediction supported brown eyes, while Louis XVI had blue eyes. This is the first draft genome generated from a person who lived in a recent historical period; however, our results suggest that this sample may not correspond to the alleged king. PMID:24763138

  14. Genomic analysis of the blood attributed to Louis XVI (1754-1793), king of France.

    PubMed

    Olalde, Iñigo; Sánchez-Quinto, Federico; Datta, Debayan; Marigorta, Urko M; Chiang, Charleston W K; Rodríguez, Juan Antonio; Fernández-Callejo, Marcos; González, Irene; Montfort, Magda; Matas-Lalueza, Laura; Civit, Sergi; Luiselli, Donata; Charlier, Philippe; Pettener, Davide; Ramírez, Oscar; Navarro, Arcadi; Himmelbauer, Heinz; Marquès-Bonet, Tomàs; Lalueza-Fox, Carles

    2014-01-01

    A pyrographically decorated gourd, dated to the French Revolution period, has been alleged to contain a handkerchief dipped into the blood of the French king Louis XVI (1754-1793) after his beheading but recent analyses of living males from two Bourbon branches cast doubts on its authenticity. We sequenced the complete genome of the DNA contained in the gourd at low coverage (~2.5×) with coding sequences enriched at a higher ~7.3× coverage. We found that the ancestry of the gourd's genome does not seem compatible with Louis XVI's known ancestry. From a functional perspective, we did not find an excess of alleles contributing to height despite being described as the tallest person in Court. In addition, the eye colour prediction supported brown eyes, while Louis XVI had blue eyes. This is the first draft genome generated from a person who lived in a recent historical period; however, our results suggest that this sample may not correspond to the alleged king. PMID:24763138

  15. Thermodynamic model for calorimetric and phase coexistence properties of coal derived fluids. Final technical report

    SciTech Connect

    Kabadi, V.N.

    1992-10-01

    The work on this project was initiated on September 1, 1989. The project consisted of three different tasks. 1. A thermodynamic model to predict VLE and calorimetric properties of coal liquids. 2. VLE measurements at high temperature and high pressure for coal model compounds and 3. Chromatographic characterization of coal liquids for distribution of heteroatoms. The thermodynamic model developed is an extension of the previous model developed for VLE of coal derived fluids (DOE Grant no. FG22-86PC90541). The model uses the modified UNIFAC correlation for the liquid phase. Some unavailable UNIFAC interactions parameters have been regressed from experimental VLE and excess enthalpy data. The model is successful in predicting binary VLE and excess enthalpy data. Further refinements of the model are suggested. An apparatus for the high pressure high temperature VLE data measurements has been built and tested. Tetralin-Quinoline is the first binary system selected for data measurements. The equipment was tested by measuring 325{degree}C isotherm for this system and comparing it with literature data. Additional isotherms at 350{degree}C and 370{degree}C have been measured. The framework for a characterization procedure for coal derived liquids has been developed. A coal liquid is defined by a true molecular weight distribution and distribution of heteroatoms as a function of molecular weights. Size exclusions liquid chromatography, elemental analysis and FTIR spectroscopy methods are used to obtain the molecular weight and hetroatom distributions. Further work in this area should include refinements of the characterization procedure, high temperature high pressure VLE data measurements for selective model compound binary systems, and improvement of the thermodynamic model using the new measured data and consistent with the developments in the characterization procedure.

  16. Adiabatic Heat of Hydration Calorimetric Measurements for Reference Saltstone Waste

    SciTech Connect

    Bollinger, James

    2006-01-12

    The production of nuclear materials for weapons, medical, and space applications from the mid-1950's through the late-1980's at the Savannah River Site (SRS) generated approximately 35 million gallons of liquid high-level radioactive waste, which is currently being processed into vitrified glass for long-term storage. Upstream of the vitrification process, the waste is separated into three components: high activity insoluble sludge, high activity insoluble salt, and very low activity soluble salts. The soluble salt represents 90% of the 35 million gallons of overall waste and is processed at the SRS Saltstone Facility, where it mixed with cement, blast furnace slag, and flyash, creating a grout-like mixture. The resulting grout is pumped into aboveground storage vaults, where it hydrates into concrete monoliths, called saltstone, thus immobilizing the low-level radioactive salt waste. As the saltstone hydrates, it generates heat that slowly diffuses out of the poured material. To ensure acceptable grout properties for disposal and immobilization of the salt waste, the grout temperature must not exceed 95 C during hydration. Adiabatic calorimetric measurements of the heat generated for a representative sample of saltstone were made to determine the time-dependent heat source term. These measurements subsequently were utilized as input to a numerical conjugate heat transfer model to determine the expected peak temperatures for the saltstone vaults.

  17. Energy calibration of Calorimetric Electron Telescope (CALET) in space

    NASA Astrophysics Data System (ADS)

    Niita, Tae; Torii, Shoji; Akaike, Yosui; Asaoka, Yoichi; Kasahara, Katsuaki; Ozawa, Shunsuke; Tamura, Tadahisa

    2015-06-01

    The Calorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States. CALET will measure the flux of cosmic ray electrons (including positrons) up to 20 TeV, gamma-rays up to 10 TeV and nuclei from Z = 1 up to 40 up to 1000 TeV during a two-year mission on the International Space Station (ISS), extendable to five years. The unique feature of CALET is its thick, fully active calorimeter that allows measurements well into the TeV energy region with excellent energy resolution (< 3 %), coupled with a fine imaging upper calorimeter to accurately identify the starting point of electromagnetic showers. For continuous high performance of the detector, it is required to calibrate each detector component on orbit. We use the measured response to minimum ionizing particles for the energy calibration, taking data in a dedicated trigger mode and selecting useful events in off-line analysis. In this paper, we present on-orbit and off-line data handling methods for the energy calibration developed through beam tests at CERN-SPS and Monte Carlo simulations.

  18. Low Temperature Calorimetric Investigation of the Spin Glasses: MERCURY(1-X)MANGANESE(X)TELLURIDE and COBALT(X)GALLIUM(1-X); and of the Compounds: Mercury-Telluride Alpha - Mercury Sulfide, Beta - Mercury Sulfide, THALLIUM(3)ARSENIC SELENIDE(3), THALLIUM(3)ANTIMONY SULFIDE(3), Silver-Thallium - and Silver-Thallium

    NASA Astrophysics Data System (ADS)

    Akbarzadeh, Hadi

    A systematic study of the low-dc-field magnetic susceptibility and the specific heat has been carried out on mixes Hg(,1-x)Mn(,x)Te crystals, in the composition range 0 (LESSTHEQ) x (LESSTHEQ) 0.35. The alloy with x = 0.35 showed spin-glass behavior below T = 10.9 K. The observed spin-glass phase is ascribed to the frustration of the antiferromagnetic interactions. For x (LESSTHEQ) 0.25, the Hg(,1-x)Mn(,x)Te samples remain paramagnetic down to 1 K. Experimental results for the specific heat and the susceptibility for x < 0.1 are discussed in terms of a cluster model which leads to an estimated value of the antiferromagnetic exchange constant J/k (DBLTURN) -0.7 (+OR-) 0.3 K. When a random distribution of Mn ions over the fcc sublattice is assumed, calculated values for the specific heat and the susceptibility differ substantially from the experimental results for the low Mn concentration, leading to the conclusion that the magnetic ions prefer to cluster rather than to remain isolated in Hg(,1-x)Mn(,x)Te. Low temperature specific heat of the spin glass compounds Co(,x)Ga(,1-x). with x between 0.49 and 0.58 are presented. For all samples the excess specific heat in zero magnetic field initially contains a term linear in temperature, and for x > 0.52 it also has contributions by the cobalt nuclei, proportional to T('-2), and a spin wave contribution proportional to T('3/2). This last term indicates the coexistence of spin glass and ferromagnetic properties. A simple two level system model fits the spin glass specific heat very well. The agreement between experimental and calculated specific heat shows that individual AS defects are responsible for the thermal properties. To explain hysteresis and remanence objects containing thousands of AS defects have been proposed. On increasing the temperature some objects become unfrozen. We speculate that the individual AS defects in the unfrozen objects can adjust themselves over their own two levels and so contribute to the thermal properties. Specific heats of mercury chalcogenides (HgTe, HgSe, (alpha)-HgS, (beta)-HgS) and red HgI(,2) have been measured in the temperature range of 0.4 - 50 K. All materials display well defined maxima in CT('-3) which indicate the presence of low-lying modes described by Einstein oscillators. The specific heats of Tl(,3)AsSe, Tl(,3)SbS(,3), AgTlS, and AgTlSe have been measured between 1 and 50 K. The Debye temperatures are, respectively: 140, 145, 160, 140 K. Above 2.5 K an additional contribution is noticed which indicates low-lying optical modes.

  19. 45 CFR 233.145 - Expiration of medical assistance programs under titles I, IV-A, X, XIV and XVI of the Social...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., 1972, had in effect a State plan approved under title XIX of the Social Security Act, section 1121 of... titles I, IV-A, X, XIV and XVI of the Social Security Act. 233.145 Section 233.145 Public Welfare..., XIV and XVI of the Social Security Act. (a) Under the provisions of section 121(b) of Pub. L....

  20. 45 CFR 233.145 - Expiration of medical assistance programs under titles I, IV-A, X, XIV and XVI of the Social...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., 1972, had in effect a State plan approved under title XIX of the Social Security Act, section 1121 of... titles I, IV-A, X, XIV and XVI of the Social Security Act. 233.145 Section 233.145 Public Welfare..., XIV and XVI of the Social Security Act. (a) Under the provisions of section 121(b) of Pub. L....

  1. Finite size effects on calorimetric cooperativity of two-state proteins

    NASA Astrophysics Data System (ADS)

    Li, Mai Suan; Klimov, D. K.; Thirumalai, D.

    2005-05-01

    Finite size effects on the calorimetric cooperatity of the folding-unfolding transition in two-state proteins are considered using the Go lattice models with and without side chains. We show that for models without side chains a dimensionless measure of calorimetric cooperativity ?2 defined as the ratio of the vant Hoff to calorimetric enthalpy does not depend on the number of amino acids N. The average value ?2bar?{3}/{4} is lower than the experimental value ?2?1. For models with side chains ?2 approaches unity as ?2?N?, where ??0.17. Above the critical chain length Nc?135 these models can mimic the truly all-or-non folding-unfolding transition.

  2. Comparing M31 and Milky Way satellites: The extended star formation histories of Andromeda II and Andromeda XVI

    SciTech Connect

    Weisz, Daniel R.; Skillman, Evan D.; McQuinn, Kristen B. W.; Hidalgo, Sebastian L.; Monelli, Matteo; Gallart, Carme; Aparicio, Antonio; McConnachie, Alan; Stetson, Peter B.; Bernard, Edouard J.; Boylan-Kolchin, Michael; Cassisi, Santi; Cole, Andrew A.; Ferguson, Henry C.; Irwin, Mike; Martin, Nicolas F.; Mayer, Lucio; Navarro, Julio F.

    2014-07-01

    We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; M{sub V} = –12.0; log(M {sub *}/M {sub ☉}) ∼ 6.7) and Andromeda XVI (And XVI; M{sub V} = –7.5; log(M {sub *}/M {sub ☉}) ∼ 4.9) yielding color-magnitude diagrams that extend at least 1 mag below the oldest main-sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50%-70% of their total stellar mass between 12.5 and 5 Gyr ago (z ∼ 5-0.5) and both were abruptly quenched ∼5 Gyr ago (z ∼ 0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context.

  3. Comparing M31 and Milky Way Satellites: The Extended Star Formation Histories of Andromeda II and Andromeda XVI

    NASA Astrophysics Data System (ADS)

    Weisz, Daniel R.; Skillman, Evan D.; Hidalgo, Sebastian L.; Monelli, Matteo; Dolphin, Andrew E.; McConnachie, Alan; Bernard, Edouard J.; Gallart, Carme; Aparicio, Antonio; Boylan-Kolchin, Michael; Cassisi, Santi; Cole, Andrew A.; Ferguson, Henry C.; Irwin, Mike; Martin, Nicolas F.; Mayer, Lucio; McQuinn, Kristen B. W.; Navarro, Julio F.; Stetson, Peter B.

    2014-07-01

    We present the first comparison between the lifetime star formation histories (SFHs) of M31 and Milky Way (MW) satellites. Using the Advanced Camera for Surveys on board the Hubble Space Telescope, we obtained deep optical imaging of Andromeda II (And II; MV = -12.0 log(M sstarf/M ⊙) ~ 6.7) and Andromeda XVI (And XVI; MV = -7.5 log(M sstarf/M ⊙) ~ 4.9) yielding color-magnitude diagrams that extend at least 1 mag below the oldest main-sequence turnoff, and are similar in quality to those available for the MW companions. And II and And XVI show strikingly similar SFHs: both formed 50%-70% of their total stellar mass between 12.5 and 5 Gyr ago (z ~ 5-0.5) and both were abruptly quenched ~5 Gyr ago (z ~ 0.5). The predominance of intermediate age populations in And XVI makes it qualitatively different from faint companions of the MW and clearly not a pre-reionization fossil. Neither And II nor And XVI appears to have a clear analog among MW companions, and the degree of similarity in the SFHs of And II and And XVI is not seen among comparably faint-luminous pairs of MW satellites. These findings provide hints that satellite galaxy evolution may vary substantially among hosts of similar stellar mass. Although comparably deep observations of more M31 satellites are needed to further explore this hypothesis, our results underline the need for caution when interpreting satellite galaxies of an individual system in a broader cosmological context. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13028.

  4. Calorimetric method for determination of {sup 51}Cr neutrino source activity

    SciTech Connect

    Veretenkin, E. P. Gavrin, V. N.; Danshin, S. N.; Ibragimova, T. V.; Kozlova, Yu. P.; Mirmov, I. N.

    2015-12-15

    Experimental study of nonstandard neutrino properties using high-intensity artificial neutrino sources requires the activity of the sources to be determined with high accuracy. In the BEST project, a calorimetric system for measurement of the activity of high-intensity (a few MCi) neutrino sources based on {sup 51}Cr with an accuracy of 0.5–1% is created. In the paper, the main factors affecting the accuracy of determining the neutrino source activity are discussed. The calorimetric system design and the calibration results using a thermal simulator of the source are presented.

  5. Chemical trends of the luminescence in wide band gap II 1-xMn xVI semimagnetic semiconductors

    NASA Astrophysics Data System (ADS)

    Benecke, C.; Busse, W.; Gumlich, H.-E.

    1990-04-01

    Time resolved emission and excitation spectroscopy is used to investigate the Mn correlated luminescence in wide band gap II-VI compounds, i.e. Zn 1-xMn xS, Cd 1-xMn xSe, Zn 1-xMn xTe and Cd 1-xMn xTe. Additional Information has been obtained with CdxZnyMnzTe( x+ y+ z=1) in checking the luminescence by variation of the ratio of the cations Cd and Zn. Generally speaking, at least two distinct emissions bands can be observed for each II 1- xMn xVI compound. One emissions band is attributed to the internal transition 4T 1(G)→ 6A 1(S) of the 3d 5 electron of the Mn 2+ on regular metal sites with energies of about ≈2 eV. The other emission band is found to occur in the near infrared range of about ≈1.3 eV. This emission band is tentatively interpreted as a transition of Mn 2+ ions on interstitial sites or in small Mn chalcogenide clusters, both interpretations assuming cubic symmetry. This model is supported by the existence of low energy excitation bands and by the great similarity of the shape of the two emission bands which lead to comparable Huang-Rhys factors and effective phonon energies. Also the established trend in the experimental data of the II-VI compounds under consideration confirm this interpretation. For both the IR and the yellow Mn 2+ center, the Racah parameters B and C and the crystal field parameter Dq are determined on the basis of experimental data. As a result, the energy of both the emission and the excitation bands is predominantly determined by the sorrounding anions. These bands shift to higher energies when the anions are changed in the fixed order: Te→Se→S. Regularly, there is also a spectral shift when Zn is replaced by Cd, which is smaller than the shift due to the variation of onions.

  6. Heat capacty, relative enthalpy, and calorimetric entropy of silicate minerals: an empirical method of prediction.

    USGS Publications Warehouse

    Robinson, G.R., Jr.; Haas, J.L., Jr.

    1983-01-01

    Through the evaluation of experimental calorimetric data and estimates of the molar isobaric heat capacities, relative enthalpies and entropies of constituent oxides, a procedure for predicting the thermodynamic properties of silicates is developed. Estimates of the accuracy and precision of the technique and examples of its application are also presented. -J.A.Z.

  7. 76 FR 45309 - Social Security Ruling 11-1p; Titles II and XVI: Procedures for Handling Requests To File...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... From the Federal Register Online via the Government Publishing Office SOCIAL SECURITY ADMINISTRATION Social Security Ruling 11-1p; Titles II and XVI: Procedures for Handling Requests To File Subsequent Applications for Disability Benefits AGENCY: Social Security Administration. ACTION: Notice...

  8. 78 FR 11939 - Social Security Ruling, SSR 13-2p.; Titles II and XVI: Evaluating Cases Involving Drug Addiction...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-20

    ...We are giving notice of SSR 13-2p, in which we explain our policies for how we consider whether ``drug addiction and alcoholism'' (DAA) is material to our determination of disability in disability claims and continuing disability reviews. This SSR rescinds and replaces SSR 82-60, Titles II and XVI: Evaluation of Drug Addiction and Alcoholism. This SSR obsoletes EM...

  9. 78 FR 17744 - Social Security Ruling, SSR 13-2p; Titles II and XVI: Evaluating Cases Involving Drug Addiction...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-22

    ... Federal Register on February 20, 2013. (78 FR 11939). On page 11940, in the first column, under the... From the Federal Register Online via the Government Publishing Office SOCIAL SECURITY ADMINISTRATION Social Security Ruling, SSR 13-2p; Titles II and XVI: Evaluating Cases Involving Drug...

  10. The NC11 domain of human collagen XVI induces vasculogenic mimicry in oral squamous cell carcinoma cells.

    PubMed

    Bedal, Konstanze B; Grässel, Susanne; Spanier, Gerrit; Reichert, Torsten E; Bauer, Richard J

    2015-11-01

    Collagen XVI, a fibril-associated collagen with interrupted triple helix (FACIT) collagen, is involved in oral squamous cell carcinoma (OSCC) and glioblastoma progression. The NC11 domain of collagen XVI has been described previously with a strong implication in physiological processes. We detected the non-collagenous (NC) 11-domain in supernatants of OSCC cells after recombinant expression of full-length collagen XVI and in sera from OSCC patients and healthy individuals. Stable expression of NC11-green fluorescent protein (GFP) fusion protein in OSCC cells initiated proliferation control and block of anchorage-independent growth. Moreover, the NC11 domain triggered the generation of tubular-like net structures on laminin-rich matrix in contrast to mock-GFP control cells and cells expressing full-length collagen XVI. Taqman® quantitative PCR and diaminobenzidine staining in 2D- and 3D cell culture revealed a significantly increased gene and protein expression of VEGFR1, VEGFR2 and uPAR in recombinant NC11-GFP-expressing cells. Specific VEGF receptor inhibition with Axitinib or fetal calf serum heat inactivation prevented formation of tubular-like net structures. Accordantly, NC11-GFP coated culture slides led to an increase of focal adhesion contact formation and the upregulation of VEGFR1 and uPAR in three different non-transfected OSCC cell lines. In summary, we suggest that the NC11 domain of collagen XVI is a potential biomarker for OSCC and triggers vasculogenic mimicry via upregulation of endothelial receptors VEGFR1, VEGFR2 and uPAR in 2D- and 3D OSCC cell culture conditions. PMID:26424749

  11. Thermodynamic properties for polycyclic systems by non-calorimetric methods

    NASA Astrophysics Data System (ADS)

    Steele, W. V.; Chirico, R. D.; Klots, T. D.

    1993-03-01

    A detailed vibrational spectroscopic study of furan, pyrrole, and thiophene has been completed. These compounds form part of the base of five-membered ring systems on which the rest of the research program will be built. Several methyl-substituted derivatives were also studied. The results will be used to confirm the model for alkyl-substitution in the ring systems. Gas-phase spectra and fundamental frequency assignments were completed for 2,3- and 2,5-dihydrofuran. Those compounds initiate work on ring-puckering within the research program. A paper describing the need for third virial estimation, when using the virial equation of state to derive thermodynamic properties at pressures greater than 1 bar was completed.

  12. Non-destructive testing of an original XVI century painting on wood by ESPI system

    NASA Astrophysics Data System (ADS)

    Arena, G.; Paturzo, M.; Fatigati, G.; Grilli, M.; Pezzati, L.; Ferraro, P.

    2015-03-01

    Electronic Speckle Pattern Interferometry (ESPI), a non-contact and non-destructive optical techniques, was employed for assessing the conservation state of a XVI Century painting on wood (72x88x1,9 cm). By a long term analysis, the whole structure alterations, induced by the room temperature and relative humidity variations, were evaluated. Measurement of the whole painting structural bends was achieved. Local flaws and hidden detachments of pictorial layers from the support, which cannot be recognized by traditional art-restorer methods, were also revealed. This work was prevalently aimed at achieving a simple approach, in the laboratory practice, to get an intuitively user-friendly method for art conservators, not accustomed to high-tech or math based methods. The results demonstrate that ESPI can largely improve the traditional art conservation survey techniques.

  13. PREFACE: XVI International Youth Scientific School 'Actual Problems of Magnetic Resonance and its Applications'

    NASA Astrophysics Data System (ADS)

    Salakhov, M. Kh; Tagirov, M. S.; Dooglav, A. V.

    2013-12-01

    In 1997, A S Borovik-Romanov, the Academician of RAS, and A V Aganov, the head of the Physics Department of Kazan State University, suggested that the 'School of Magnetic Resonance', well known in the Soviet Union, should recommence and be regularly held in Kazan. This school was created in 1968 by G V Scrotskii, the prominent scientist in the field of magnetic resonance and the editor of many famous books on magnetic resonance (authored by A Abragam, B. Bleaney, C. Slichter, and many others) translated and edited in the Soviet Union. In 1991 the last, the 12th School, was held under the supervision of G V Scrotskii. Since 1997, more than 600 young scientists, 'schoolboys', have taken part in the School meetings, made their oral reports and participated in heated discussions. Every year a competition among the young scientist takes place and the Program Committee members name the best reports, the authors of which are invited to prepare full-scale scientific papers. The XVI International Youth Scientific School 'Actual problems of the magnetic resonance and its application' in its themes is slightly different from previous ones. A new section has been opened this year: Coherent Optics and Optical Spectroscopy. Many young people have submitted interesting reports on optical research, many of the reports are devoted to the implementation of nanotechnology in optical studies. The XVI International Youth Scientific School has been supported by the Program of development of Kazan Federal University. It is a pleasure to thank the sponsors (BRUKER Ltd, Moscow, the Russian Academy of Science, the Dynasty foundation of Dmitrii Zimin, Russia, Russian Foundation for Basic Research) and all the participants and contributors for making the International School meeting possible and interesting. A V Dooglav, M Kh Salakhov and M S Tagirov The Editors

  14. Calorimetric thermal-vacuum performance characterization of the BAe 80 K space cryocooler

    NASA Technical Reports Server (NTRS)

    Kotsubo, V. Y.; Johnson, D. L.; Ross, R. G., Jr.

    1992-01-01

    A comprehensive characterization program is underway at JPL to generate test data on long-life, miniature Stirling-cycle cryocoolers for space application. The key focus of this paper is on the thermal performance of the British Aerospace (BAe) 80 K split-Stirling-cycle cryocooler as measured in a unique calorimetric thermal-vacuum test chamber that accurately simulates the heat-transfer interfaces of space. Two separate cooling fluid loops provide precise individual control of the compressor and displacer heatsink temperatures. In addition, heatflow transducers enable calorimetric measurements of the heat rejected separately by the compressor and displacer. Cooler thermal performance has been mapped for coldtip temperatures ranging from below 45 K to above 150 K, for heatsink temperatures ranging from 280 K to 320 K, and for a wide variety of operational variables including compressor-displacer phase, compressor-displacer stroke, drive frequency, and piston-displacer dc offset.

  15. An Improved Formulation for Calorimetric Emittance Testing of Spacecraft Thermal Control Coatings

    NASA Technical Reports Server (NTRS)

    Kauder, Lonny R.

    2008-01-01

    Spacecraft often really heavily on passive thermal control to maintain operating temperature. An important parameter in the spacecraft heat balance equation is the emittance of thermal control coatings as a function of coating temperature. One method for determining the emittance of spacecraft thermal control from elevated temperature to cryogenic temperatures relies on a calorimetric technique. The fundamental equation governing this test method can be found in numerous places in the literature and although it generally provides reasonable results, its formulation is based on a conceptual flaw that only becomes apparent when the sample temperature approaches the wall temperature during testing. This paper investigates the cause for this error and develops the correct formulation for calorimetric emittance testing. Experimental data will also be presented that illustrates the difference between the two formulations and the resulting difference in the calculated emittance.

  16. The calorimetric spectrum of the electron-capture decay of 163Ho. The spectral endpoint region

    NASA Astrophysics Data System (ADS)

    De Rújula, A.; Lusignoli, M.

    2016-05-01

    The electron-neutrino mass (or masses and mixing angles) may be directly measurable in weak electron-capture decays. The favoured experimental technique is "calorimetric". The optimal nuclide is 163Ho, and several experiments (ECHo, HOLMES and NuMECS) are currently studying its decay. The most relevant range of the calorimetric-energy spectrum extends for the last few hundred eV below its endpoint. It has not yet been well measured. We explore the theory, mainly in the cited range, of electron capture in 163Ho decay. A so far neglected process turns out to be most relevant: electron-capture accompanied by the shake-off of a second electron. Our two main conclusions are very encouraging: the counting rate close to the endpoint may be more than an order of magnitude larger than previously expected; the "pile-up" problem may be significantly reduced.

  17. Application of Electrical and Calorimetric Methods to the A.C. Loss Characterization of Cable Conductors

    SciTech Connect

    Coletta, C.; Gherardi, L.; Gomory, F.; Cereda, E.; Ottoboni, V.; Daney, D.E.; Maley, M.P.; Zannella, S.

    1998-09-13

    Due to the higher currents (and therefore higher losses) compared to individual wires and tapes, the ac loss characterization of HTS cable conductors carrying transport current can be performed using calorimetric as well as electrical methods. We discuss the main features of two calorimetric methods, one based on temperature profile determination, and one, more recently developed, based on nitrogen boil-off rate, and of the electrical method, substantially derived from that already established for tapes, based on voltage measurement by a Lock-In amplifier. Advantages and limits of each approach are analyzed and compared. Tests have been carried out with the three methods on samples 1 to 1.5 m long cut from a Bi-2223 cable conductor prototype fabricated by Pirelli in a longer length. Results obtained from measurements covering a wide range of currents are compared and thoroughly discussed.

  18. Use of calorimetric assay for operational and accountability measurements of pure plutonium metal

    SciTech Connect

    Cremers, Teresa L; Sampson, Thomas E

    2010-01-01

    Plutonium pure metal products (PMP) are high purity plutonium metal items produced by electrorefining. The plutonium metal is produced as an approximately 3-kg ring. Accountability measurements for the electro-refining runs are typically balance/weight factor (incoming impure metal), chemistry (pure metal rings), and calorimetric assay or neutron counting of the crucibles and other wastes. The PMP items are qualified for their end use by extensive chemical assay. After PMP materials are made they are often sent to the vault for storage before being sent to the casting process, the next step in the production chain. The chemical assay of PMP items often takes a few weeks; however, before the metal items are allowed into the vault they must be measured. Non-destructive assay personnel measure the metals either by multiplicity neutron counting or calorimetric assay, depending on which instrument is available, thus generating comparisons between non-destructive assay and chemical assay. The suite of measurements, calorimetric assay, chemical assay, and neutron mUltiplicity counting is compared for a large group of PMP items.

  19. Calorimetric versus Growth Microbial Analysis of Cellulase Enzymes Acting on Cellulose

    PubMed Central

    Lovrien, Rex E.; Williams, Karl K.; Ferrey, Mark L.; Ammend, David A.

    1987-01-01

    Assay of cellulase enzymology on cellulose was investigated by two methods: (i) plate colony counting to determine microbial growth and (ii) microbial calorimetry. These methods were chosen because they accept raw samples and have the potential to be far more specific than spectrophotometric reducing sugar assays. Microbial calorimetry requires ca. 0.5 to 1 h and 10 to 100 μM concentrations of cellulolytic lower sugars (glucose and cellobiose). Growth assay (liquid culture, plating, colony counting) requires 15 to 20 h and ca. 0.5 mM sugars. Microbial calorimetry requires simply aerobic metabolism, whereas growth assay requires completion of the cell cycle. A stripping technique is described for use in conjunction with the calorimetric method to enable separate analysis of the two sugars. Mixtures of glucose and cellobiose are equilibrated with Escherichia coli and spun out to remove glucose. The supernatant is calorimetrically combusted with Klebsiella sp. to quantitate cellobiose, and the same organism combusting the nonstripped mixture gives heat proportional to the sum of the two sugars. Calorimetry of cellulolysis products from individual exo- and endocellulases, and from their reconstituted mixture, was carried out to develop a microbial calorimetric means for demonstrating enzyme synergism. PMID:16347508

  20. Calorimetric investigation of triazole-bridged Fe(II) spin-crossover one-dimensional materials: measuring the cooperativity.

    PubMed

    Roubeau, Olivier; Castro, Miguel; Burriel, Ramón; Haasnoot, Jaap G; Reedijk, Jan

    2011-03-31

    The relevance of abrupt magnetic and optical transitions exhibiting bistability in spin-crossover solids has been pointed out for their potential applications in optical or memory devices. In this respect, triazole-based one-dimensional coordination polymers are widely recognized as one of the most interesting systems. The measure of the interaction among spin-crossover centers at the origin of such cooperative behavior is of paramount importance and has so far been realized through modeling of spin-crossover curves derived mostly from magnetic measurements. Here, a new series of triazole-based one-dimensional coordination polymers of formula [Fe(Rtrz)(3)](A)(2)·xH(2)O with R = methoxyethyl and A = monovalent anion has been prepared that show complete and abrupt spin-crossover phenomenon as shown by magnetic measurements. The spin-crossover transition in these and related compounds is studied by differential scanning calorimetry, and the thermodynamic excess enthalpies and entropies associated with the phenomenon are derived systematically. Then the cooperative character of the spin-crossover in these materials is quantified by use of two widely used models, so-called Slichter and Drickamer and domain models. The same procedure is applied to spin-crossover curves of similar compounds available in the literature and for which calorimetric studies have been reported. The experimental thermodynamic figures, in particular the excess enthalpies, are shown to be clearly correlated to the output parameters of both models, thus providing a direct, experimental, quantitative measure of the cooperative character of the spin-crossover phenomenon. PMID:21381636

  1. Calorimetric and Spectroscopic Studies of the Thermotropic Phase Behavior of the n-Saturated 1,2-Diacylphosphatidylglycerols

    PubMed Central

    Zhang, Yuan-Peng; Lewis, Ruthven N. A. H.; McElhaney, Ronald N.

    1997-01-01

    The polymorphic phase behavior of a homologous series of n-saturated 1,2-diacyl phosphatidylglycerols (PGs) was studied by differential scanning calorimetry and Fourier transform infrared and 31P-nuclear magnetic resonance spectroscopy. When dispersed in aqueous media under physiologically relevant conditions, these compounds exhibit two thermotropic phase transitions that are structurally equivalent to the well-characterized pretransitons and gel/liquid-crystalline phase transitions exhibited by bilayers of the corresponding 1,2-diacyl phosphatidylcholines. Furthermore, when incubated at low temperatures, their gel phases spontaneously transform into one or more solid-like phases that appear to be highly ordered, quasicrystalline bilayers that are probably partially dehydrated. The quasicrystalline structures, which form upon short-term, low-temperature annealing of these lipids, are meta-stable with respect to more stable structures, to which they eventually transform upon prolonged low-temperature incubation. The rates of formation of the quasicrystalline phases of the PGs generally tend to decrease as hydrocarbon chain length increases, and PGs whose hydrocarbon chains contain an odd number of carbon atoms tend to be slower than those of neighboring even-numbered homologs. The calorimetric data also indicate that the quasicrystalline phases of these compounds become progressively less stable relative to both their gel and liquid-crystalline phases as the length of the hydrocarbon chain increases and that they decompose either to the liquid-crystalline phase (short- and medium-chain compounds) or to the normal gel phase (long-chain compounds) upon heating. The spectroscopic data indicate that although there is odd-even alternation in the structures of the quasicrystalline phases formed upon short-term low-temperature incubation of these compounds, the structural features of the stable quasicrystalline phases eventually formed are all similar. Furthermore, the degree of hydration and the nature of hydrogen bonding interactions in the headgroup and interfacial regions of these PG bilayers differ significantly from that observed in all other phospholipid bilayers studied so far. We suggest that many of the properties of PG bilayers can be rationalized by postulating that the glycerol moiety of the polar headgroup is directly involved in shielding the negative charges at the surface of the bilayer by means of hydration-like hydrogen bonding interactions with the phosphate moiety. PMID:9017203

  2. Calorimetric Study of Several Cuprates with Restricted Dimensionality

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Masaaki; Furuta, Tomoki; Ishikawa, Masayasu

    1996-09-01

    By means of specific heat and magnetic susceptibility measurements we investigated the magnetic compounds of various crystal structure, CuWO4, LiCuVO4, CuSb2O6, CuNb2O6 and CuBi2O4. All of these cuprates revealed strong one-dimensional (1D) correlations persisting up to very high temperatures which are well explained by the S=1/2 Heisenberg antiferromagnetic linear-chain model. At lower temperatures they showed various long-range magnetic ordering except for CuNb2O6. In particular, we observed a rather unusual transition at 2.4 K for LiCuVO4 which is conjectured to be a transition to the S=1/2 quadratic Ising antiferromagnet, thereby demonstrating a dimensional cross-over of correlations from 1D to 2D. The magnetic susceptibility and specific heat exhibit a critical point and a logarithmic divergence at 2.4 K, respectively, as predicted by theory. We herein report the experimental results and the preliminary analyses of these low-dimensional cuprates.

  3. Method for measurement of diffusivity: Calorimetric studies of Fe/Ni multilayer thin films

    SciTech Connect

    Liu, JX; Barmak, K

    2015-07-15

    A calorimetric method for the measurement of diffusivity in thin film multilayers is introduced and applied to the Fe Ni system. Using this method, the diffusivity in [Fe (25 nm)/Ni (25 nm)](20) multilayer thin films is measured as 4 x 10(-3)exp(-1.6 +/- 0.1 eV/ k(B)T) cm(2)/s, respectively. The diffusion mechanism in the multilayers and its relevance to laboratory synthesis of L1(0) ordered FeNi are discussed. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Significance of partial and total cohesion parameters of pharmaceutical solids determined from dissolution calorimetric measurements.

    PubMed

    Rey-Mermet, C; Ruelle, P; Nam-Trân, H; Buchmann, M; Kesselring, U W

    1991-05-01

    The total and partial adhesion-derived cohesion parameters of three solid pharmaceutical substances (caffeine, theophylline, and phenylbutazone) were determined from dissolution calorimetric measurements, a new technique devised for this purpose. Calorimetry has the advantage of leading directly to enthalpies, from which the solute cohesion parameter(s) is(are) deduced. An equation was developed that relates partial molar enthalpies of mixing (obtained by subtracting enthalpies of fusion from enthalpies of dissolution) to the cohesion parameters of the solute and of the solvents. Solvents were selected on the basis of their known cohesion parameters by applying the experimental research methodology. PMID:1866379

  5. Calorimetric study on the state of aromatic molecules sorbed on silicalite

    SciTech Connect

    Thamm, H.

    1987-01-01

    Differential heats of sorption have been determined calorimetrically for benzene, toluene, ethylbenzene, and p-xylene on silicate as a function of pore filling. In all cases abrupt changes in the state of the sorbed molecules are observed when the amount sorbed exceeds 1 molecule per 1/4 unit cell. While in the case of benzene, toluene, and ethylbenzene sorbate-sorbate interaction occurs only above 1 molecule per 1/4 unit cell, the sorbed p-xylene molecules interact with each other below this loading.

  6. Calorimetric support of directional-hemispherical reflection measurements in the infrared spectral range.

    PubMed

    Richter, W; Sarge, S M; Kämmer, F

    1994-03-01

    Measurements of the directional-hemispherical reflectance ρ with the Physikalisch-Technische Bundesanstalt IR sphere reflectometer have been confirmed by calorimetric determination of the absorptance α in the same geometrical conditions (irradiation at 10°, hemispherical reflection). The good agreement of ρ with (1 - α) on both highly reflecting and low-reflecting surfaces indicates that in the mid-IR spectral range the integrating sphere reflectometer is capable of essentially correct reflectance measurements of diffusely reflecting surfaces, with an estimated uncertainty of 0.01 after correction for a small systematic deviation. This capability opens up the possibility of developing IR reflectance standards. PMID:20862150

  7. XVI IAGA workshop on geomagnetic observatory instruments, data acquisition and processing. Hyderabad, India, October 2014: Brief review XVI IAGA workshop on geomagnetic observatory in-struments, data acquisition and processing. Hyderabad, India, October 2014: Brief review

    NASA Astrophysics Data System (ADS)

    Khomutov, Sergey

    2015-12-01

    The brief review of the XVI IAGA Workshop on Geomagnetic Observatory Instruments Data Acquisition and Processing (Hyderabad, India, October 2014) is presented. Much attention is given to new magnetometers and software for practical work of magnetologists as well as to archive data. Reports on new devices point to the tendency that in the near future, the technique for obtaining the total field vector data adopted by INTERMAGNET will remain changeless as the combination of absolute (manual) and variation measurements. Besides, a low interest of the community to software necessary for full processing of magnetic measurements directly in observatories should be also noticed.

  8. Kinetics of degradation of diclofenac sodium in aqueous solution determined by a calorimetric method.

    PubMed

    Chadha, R; Kashid, N; Jain, D V S

    2003-09-01

    An isothermal heat conduction microcalorimeter has been used to study the stability of diclofenac sodium both alone and its inclusion complex with beta-cyclodextrin in aqueous solution. The rates of heat evolved during degradation of diclofenac sodium have been measured by a highly sensitive microcalorimetric technique as function of concentration, pH and temperature. The calorimetric accessible data have been incorporated in the equations for determination of rate constants, change in enthalpy and order of reaction. The decomposition of diclofenac sodium both alone and its inclusion complex with beta-cyclodextrin in solution corresponds to a pseudo-first order reaction. The values of rate constants, k's at 338.15 K, (calculated from the variation of heat evolution with the time) for the degradation of diclofenac sodium at pH 5, 6, 7, 8 and its inclusion complex with beta-cyclodextrin at pH 7 are found to be 4.71 x 10(-4), 5.69 x 10(-4), 6.12 x 10(-)4, 6.57 x 10(-4) and 4.26 x 10(-4) h(-1) respectively. There is good agreement between calorimetric determined t(0.5) and literature values. It has been found that beta-cyclodextrin retards the degradation of diclofenac sodium. The kinetic parameters have been calculated for the reaction. The negative entropy of activation suggests the formation of an ordered transition state. PMID:14531458

  9. Calorimetric method of ac loss measurement in a rotating magnetic field.

    PubMed

    Ghoshal, P K; Coombs, T A; Campbell, A M

    2010-07-01

    A method is described for calorimetric ac-loss measurements of high-T(c) superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines. PMID:20687748

  10. Calorimetric method of ac loss measurement in a rotating magnetic field

    SciTech Connect

    Ghoshal, P. K.; Coombs, T. A.; Campbell, A. M.

    2010-07-15

    A method is described for calorimetric ac-loss measurements of high-T{sub c} superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.

  11. Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

    SciTech Connect

    Ankowski, Artur M.; Benhar, Omar; Coloma, Pilar; Huber, Patrick; Jen, Chun -Min; Mariani, Camillo; Meloni, Davide; Vagnoni, Erica

    2015-10-22

    To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two νμ → νμ disappearance experiments operating in different energy regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an O(10%) accuracy to avoid a significant bias in the extracted oscillation parameters. Thus, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.

  12. Calorimetric thermoelectric gas sensor for the detection of hydrogen, methane and mixed gases.

    PubMed

    Park, Nam-Hee; Akamatsu, Takafumi; Itoh, Toshio; Izu, Noriya; Shin, Woosuck

    2014-01-01

    A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3) and cold (Pt/α-Al2O3) ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS), combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100-400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%. PMID:24818660

  13. Stabilization of Cu(I) for binding and calorimetric measurements in aqueous solution†

    PubMed Central

    Johnson, Destinee K.; Stevenson, Michael J.; Almadidy, Zayed A.; Jenkins, Sharon E.; Wilcox, Dean. E.; Grossoehme, Nicholas E.

    2015-01-01

    Conditions have been developed for the comproportionation reaction of Cu2+ and copper metal to prepare aqueous solutions of Cu+ that are stabilized from disproportionation by MeCN and other Cu+-stabilizing ligands. These solutions were then used in ITC measurements to quantify the thermodynamics of formation of a set of Cu+ complexes (CuI(MeCN)3+, CuIMe6Trien+, CuI(BCA)23−, CuI(BCS)23−), which have stabilities ranging over 15 orders of magnitude, for their use in binding and calorimetric measurements of Cu+ interaction with proteins and other biological macromolecules. These complexes were then used to determine the stability and thermodynamics of formation of a 1 : 1 complex of Cu+ with the biologically important tri-peptide glutathione, GSH. These results identify Me6Trien as an attractive Cu+-stabilizing ligand for calorimetric experiments, and suggest that caution should be used with MeCN to stabilize Cu+ due to its potential for participating in unquantifiable ternary interactions. PMID:26327397

  14. Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

    DOE PAGESBeta

    Ankowski, Artur M.; Benhar, Omar; Coloma, Pilar; Huber, Patrick; Jen, Chun -Min; Mariani, Camillo; Meloni, Davide; Vagnoni, Erica

    2015-10-22

    To be able to achieve their physics goals, future neutrino-oscillation experiments will need to reconstruct the neutrino energy with very high accuracy. In this work, we analyze how the energy reconstruction may be affected by realistic detection capabilities, such as energy resolutions, efficiencies, and thresholds. This allows us to estimate how well the detector performance needs to be determined a priori in order to avoid a sizable bias in the measurement of the relevant oscillation parameters. We compare the kinematic and calorimetric methods of energy reconstruction in the context of two νμ → νμ disappearance experiments operating in different energymore » regimes. For the calorimetric reconstruction method, we find that the detector performance has to be estimated with an O(10%) accuracy to avoid a significant bias in the extracted oscillation parameters. Thus, in the case of kinematic energy reconstruction, we observe that the results exhibit less sensitivity to an overestimation of the detector capabilities.« less

  15. Calorimetric Thermoelectric Gas Sensor for the Detection of Hydrogen, Methane and Mixed Gases

    PubMed Central

    Park, Nam-Hee; Akamatsu, Takafumi; Itoh, Toshio; Izu, Noriya; Shin, Woosuck

    2014-01-01

    A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3) and cold (Pt/α-Al2O3) ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS), combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100–400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%. PMID:24818660

  16. ESTIMATION OF BARE-SOIL EVAPORATION USING A CALORIMETRIC APPROACH WITH HEAT FLUX MEASURED AT MULTIPLE DEPTHS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An assumption in calorimetric methods for soil heat flux is that sensible heat terms can be balanced (i.e., if the heat flux is known at one depth, the heat flux at another depth may be determined by monitoring the change in heat storage). Latent heat from water evaporation is assigned to the energy...

  17. Soluble expression and sodium channel activity of lt16a, a novel framework XVI conotoxin from the M-superfamily.

    PubMed

    Zhou, Maojun; Wang, Lei; Wu, Yun; Liu, Junliang; Sun, Dandan; Zhu, Xiaoyan; Feng, Yuchao; Qin, Mengying; Chen, Shangwu; Xu, Anlong

    2015-05-01

    A peptide toxin, lt16a, from the venom of the worm-hunting Conus litteratus, shares the typical signal peptide sequences of M-superfamily conotoxins, which usually contain six cysteine residues that are arranged in a CC-C-C-CC pattern. Interestingly, lt16a comprises 21 amino acid residues in its mature region and has a cysteine framework XVI, which is arranged in a C-C-CC pattern. The coding region of lt16a was cloned into the pTRX vector and the fusion protein was overexpressed in Escherichia coli. After cleaving the fusion protein and purifying the protein lt16a using chromatography, the mass of lt16a was found by mass spectrometry to be consistent with the expected mass of 2357.7 Da. Whole-cell patch clamp experiments demonstrated that lt16a could inhibit both the TTX-sensitive and TTX-resistant sodium currents in adult rat dorsal root ganglion neurons. The inhibition of lt16a on TTX-resistant sodium currents was stronger than on TTX-sensitive sodium currents. To our knowledge, this is the first report of a framework XVI conotoxin that can inhibit voltage-gated sodium channel currents in mammalian sensory neurons. This report helps facilitates an understanding of the sequence diversity of conotoxins. PMID:25600641

  18. Calorimetric determination of thermal parameters for the Li/BrCl in SOCl2 (BCX) chemistry

    NASA Technical Reports Server (NTRS)

    Darcy, Eric C.; Kalu, Eric E.; White, Ralph E.

    1990-01-01

    The heat capacity of a Li-BCX DD-cell was found to be dependent on its state of charge by drop calorimetry measurements. The method of drop calorimetry involves measuring the energy (joules) gained or lost from a sample that is transferred from a bath at temperature A to one at temperature B. The thermoneutral potential is defined as the cell potential where the cell electrochemical reactions are neither exothermic nor endothermic. A Hart scientific calorimeter system, Model No. S77XX, designed for heat conduction calorimetry and drop calorimetry was used. Calorimetric analysis yielded a thermoneutral potential of 4.14 volts and a cell heat capacity dependent on the state of charge.

  19. On the measurement of energy fluxes in plasmas using a calorimetric probe and a thermopile sensor

    NASA Astrophysics Data System (ADS)

    Cormier, Pierre-Antoine; Stahl, Marc; Thomann, Anne-Lise; Dussart, Rémi; Wolter, Matthias; Semmar, Nadjib; Mathias, Jacky; Kersten, Holger

    2010-11-01

    Two different diagnostics for the determination of the energy influx in plasma processes were used to characterize an ion beam source and an asymmetric RF discharge. The related energy fluxes were measured in dependence on the ion energy and on the RF power, respectively. The first sensor, called HFM (Heat Flux Microsensor) is a thermopile which allows for direct energy flux measurements. With the second sensor, a calorimetric probe, the energy influx has been calculated from the temporal temperature evolution preliminarily registered. Although the working principle of both sensors is different, the obtained results are in good agreement. In the ion beam (<1.5 keV)) rather high energy influxes are achieved (up to 700 mW cm-2), whereas the values measured in the asymmetric RF discharge were lower than 50 mW cm-2 for discharge powers in the range 10-100 W. The performances and limitations of both sensors are compared and discussed.

  20. Rapid discrimination of DNA strands using an opto-calorimetric microcantilever sensor.

    PubMed

    Lee, Dongkyu; Hwang, Kyo Seon; Kim, Seonghwan; Thundat, Thomas

    2014-12-21

    A rapid technique for quantitative detection and discrimination of DNA strands without using immobilized probe molecules is demonstrated using an opto-calorimetric, self-powered sensor based on a Pb(Zr(0.52)Ti(0.48))O3 (PZT) microcantilever. Microcalorimetric infrared (IR) spectroscopy provides excellent chemical selectivity based on the unique molecular vibrational characteristics of each nucleotide in the mid IR region. The piezoelectric and pyroelectric properties of the PZT microcantilever were exploited in the quantitative detection and discrimination of adsorbed DNA strands with their spectral characteristics. We report the unique spectral characteristics of different DNA nucleotides that are monitored by wavelength-dependent temperature variations for different relative molar ratio of each nucleotide. This approach offers a fast, label-free technique which is highly sensitive and selective for the detection of single nucleotide differences in DNA strands and has the potential to be used as a rapid prescreening biosensor for various biomolecules. PMID:25300415

  1. Specific volume study of a bulk metallic glass far below its calorimetrically determined glass transition temperature

    NASA Astrophysics Data System (ADS)

    Luckabauer, M.; Kühn, U.; Eckert, J.; Sprengel, W.

    2014-05-01

    High-precision LASER dilatometry with a unique measurement setup was applied to the bulk metallic glass alloy Zr52.5Ti5Cu17.9Ni14.6Al10 (Vit105) for specific volume studies. Employing small temperature steps of ΔT =5 and 10 K and long measurement times effective heating rates of the order of 10-2 K/min were realized and changes of the specific volume were measured with a resolution of ΔV /V=10-6 down to 573 K. The temperature regime of these experiments is far below a calorimetrically determined glass transition of Tgcalor=659 K (5 K/min). The experimental results strongly support theoretical predictions for the existence of an ideal glass transition that was observed in this study at Tg=628 K for this bulk metallic glass model alloy.

  2. Total hemispherical emittance measured at high temperatures by the calorimetric method

    SciTech Connect

    DiFilippo, F.; Mirtich, M.J.; Banks, B.A.; Stidham, C.; Kussmaul, M.

    1994-09-01

    A calorimetric vacuum emissometer (CVE) capable of measuring total hemispherical emittance of surfaces at elevated temperatures was designed, built, and tested. Several materials with a wide range of emittances were measured in the CVE between 773 to 923 K. These results were compared to values calculated from spectral emittance curves measured in a room temperature Hohlraum reflectometer and in an open-air elevated temperature emissometer. The results differed by as much as 0.2 for some materials but were in closer agreement for the more highly-emitting, diffuse-reflecting samples. The differences were attributed to temperature, atmospheric, and directional effects, and errors in the Hohlraum and emissometer measurements ({+-} 5 percent). The probable error of the CVE measurements was typically less than 1 percent.

  3. The Bayer Facts of Science Education XVI: "US STEM Workforce Shortage--Myth or Reality? Fortune 1000 Talent Recruiters on the Debate"

    ERIC Educational Resources Information Center

    Journal of Science Education and Technology, 2014

    2014-01-01

    A major debate is currently underway in the USA about whether there is, in fact, a science, technology, engineering and mathematics (STEM) workforce shortage in the country or not. This is the subject of the "Bayer Facts of Science Education XVI: US STEM Workforce Shortage--Myth or Reality? Fortune 1000 Talent Recruiters on the Debate."…

  4. The Bayer Facts of Science Education XVI: "US STEM Workforce Shortage--Myth or Reality? Fortune 1000 Talent Recruiters on the Debate"

    ERIC Educational Resources Information Center

    Journal of Science Education and Technology, 2014

    2014-01-01

    A major debate is currently underway in the USA about whether there is, in fact, a science, technology, engineering and mathematics (STEM) workforce shortage in the country or not. This is the subject of the "Bayer Facts of Science Education XVI: US STEM Workforce Shortage--Myth or Reality? Fortune 1000 Talent Recruiters on the Debate."

  5. Calorimetric quantification of linked equilibria in cyclodextrin/lipid/detergent mixtures for membrane-protein reconstitution.

    PubMed

    Textor, Martin; Vargas, Carolyn; Keller, Sandro

    2015-04-01

    Reconstitution from detergent micelles into lipid bilayer membranes is a prerequisite for many in vitro studies on purified membrane proteins. Complexation by cyclodextrins offers an efficient and tightly controllable way of removing detergents for membrane-protein reconstitution, since cyclodextrins sequester detergents at defined stoichiometries and with tuneable affinities. To fully exploit the potential advantages of cyclodextrin for membrane-protein reconstitution, we establish a quantitative model for predicting the supramolecular transition from mixed micelles to vesicles during cyclodextrin-mediated detergent extraction. The model is based on a set of linked equilibria among all pseudophases present in the course of the reconstitution process. Various isothermal titration-calorimetric protocols are used for quantifying a detergent's self-association as well as its colloidal and stoichiometric interactions with lipid and cyclodextrin, respectively. The detergent's critical micellar concentration, the phase boundaries in the lipid/detergent phase diagram, and the dissociation constant of the cyclodextrin/detergent complex thus obtained provide all thermodynamic parameters necessary for a quantitative prediction of the transition from micelles to bilayer membranes during cyclodextrin-driven reconstitution. This is exemplified and validated by stepwise complexation of the detergent lauryldimethylamine N-oxide in mixtures with the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine upon titration with 2-hydroxypropyl-β-cyclodextrin, both in the presence and in the absence of the membrane protein Mistic. The calorimetric approach presented herein quantitatively predicts the onset and completion of the reconstitution process, thus obviating cumbersome trial-and-error efforts and facilitating the rational optimisation of reconstitution protocols, and can be adapted to different cyclodextrin/lipid/detergent combinations. PMID:25583305

  6. Characterization of hidden defects of an original XVI century painting on wood by Electronic Speckle Pattern Interferometry

    NASA Astrophysics Data System (ADS)

    Arena, G.

    2015-03-01

    Electronic Speckle Pattern Interferometry, a non-contact and non-destructive optical diagnostic technique, was employed for evaluating the conservation state of a XVI century painting on wood. The whole structure alterations, induced by the laboratory temperature and relative humidity variations, were evaluated. Long-term analysis, by sequential recording and subsequent off-line processing of the fringes progression, was carried out. Local flaws and hidden detachments of pictorial layers from the support, which could not be recognized by traditional art-restorer survey methods, were also easily revealed. In such a case, a simple measurement approach was utilized, with the aim to get a user-friendly method for art conservators. The results demonstrate that the interferometry method can largely improve the traditional art conservation survey techniques.

  7. Calorimetric output power measurements on a CW 20 kW 7.16 GHz microwave transmitter

    NASA Technical Reports Server (NTRS)

    Perez, Raul M.; Conroy, Bruce L.

    1991-01-01

    A calorimetric measurement technique developed for NASA's Deep Space Network (DSN) transmitters that does not require data on the coolant's thermal parameters is described. Calibration of the measurement system is achieved by measuring the DC input power to the klystron and relating coolant temperature increases to this known power dissipation. Agreement between calorimetric and electrical measurements of total system power was good, the difference being less than 2 percent. The operation of the system was not greatly affected by the composition of the coolant, which was varied from pure water to 40 percent ethylene glycol by mass. Good accuracy was also shown at output power levels, which varied over a 3.6:1 range.

  8. Calorimetric determination of the thermoneutral potential of Li/BCX and Li/SOCl2 cells

    NASA Technical Reports Server (NTRS)

    Kalu, E. E.; White, R. E.; Darcy, E. C.

    1992-01-01

    Results are presented of the calorimetric determination of the effective thermoneutral potential, Eetp, of Li/BCS and Li/SOCl2 cells in the temperature range 0-60 C through a continuous recording of the cell voltage, heat flow, and current. The average effective thermoneutral potential at 25 C was 4.0 and 3.84 V for BCX and Li/SOCl2 cells, respectively. Based on the classical approach, the reversible cell potential, Er, and temperature dependence of reversible cell potential, dEr/dT, for BCX cell were 3.74 V and -0.952 mV/K, respectively, and for Li/SOCl2, Er = 3.67 V and dEr/dT = 0.567 mV/K. The thermal polarization (Eetp-E1), where E1 is the load voltage, for both cells, showed that they are the most thermally efficient near 40 C. An overall reaction proposed for the BCX chemistry is supported by the calculated thermodynamic parameters.

  9. Towed-grid system for production and calorimetric study of homogenous quantum turbulence

    NASA Astrophysics Data System (ADS)

    Ciapurin, Roman; Thompson, Kyle; Ihas, Gary G.

    2011-10-01

    The decay of quantum turbulence is not fully understood in superfluid helium at milikelvin temperatures where the viscous normal component is absent. Vibrating grid experiments performed periously produced inhomogeneous turbulence, making the results hard to interpret. We have developed experimental methods to produce homogeneous isotropic turbulence by pulling a grid at a variable constant velocity through superfluid 4He. While using calorimetric technique to measure the energy dissipation, the Meissner effect was employed to eliminate all heat sources except from turbulent decay. A controlled divergent magnetic field provides the lift to a hollow cylindrical superconducting actuator to which the grid is attached. Position sensing is performed by measuring the inductance change of a coil when a superconductor, similar to that of the actuator, is moved inside it. This position sensing technique proved to be reliable under varying temperatures and magnetic fields, making it perfect for use in the towed-grid experiment where a rise in temperature emerges from turbulent decay. Additionally, the reproducible dependency of the grid's position on the applied magnetic field enables complete control of the actuator's motion.

  10. Status and performance of the CALorimetric Electron Telescope (CALET) on the International Space Station

    NASA Astrophysics Data System (ADS)

    Adriani, O.; Akaike, Y.; Asaoka, Y.; Asano, K.; Bagliesi, M. G.; Bigongiari, G.; Binns, W. R.; Bongi, M.; Buckley, J. H.; Cassese, A.; Castellini, G.; Cherry, M. L.; Collazuol, G.; Ebisawa, K.; Di Felice, V.; Fuke, H.; Guzik, T. G.; Hams, T.; Hasebe, N.; Hareyama, M.; Hibino, K.; Ichimura, M.; Ioka, K.; Israel, M. H.; Javaid, A.; Kamioka, E.; Kasahara, K.; Katayose, Y.; Kataoka, J.; Kataoka, R.; Kawanaka, N.; Kitamura, H.; Kotani, T.; Krawczynski, H. S.; Krizmanic, J. F.; Kubota, A.; Kuramata, S.; Lomtadze, T.; Maestro, P.; Marcelli, L.; Marrocchesi, P. S.; Mitchell, J. W.; Miyake, S.; Mizutani, K.; Motz, H. M.; Moiseev, A. A.; Mori, K.; Mori, M.; Mori, N.; Munakata, K.; Murakami, H.; Nakagawa, Y. E.; Nakahira, S.; Nishimura, J.; Okuno, S.; Ormes, J. F.; Ozawa, S.; Palma, F.; Papini, P.; Rauch, B. F.; Ricciarini, S.; Sakamoto, T.; Sasaki, M.; Shibata, M.; Shimizu, Y.; Shiomi, A.; Sparvoli, R.; Spillantini, P.; Takahashi, I.; Takayanagi, M.; Takita, M.; Tamura, T.; Tateyama, N.; Terasawa, T.; Tomida, H.; Torii, S.; Tunesada, Y.; Uchihori, Y.; Ueno, S.; Vannuccini, E.; Wefel, J. P.; Yamaoka, K.; Yanagita, S.; Yoshida, A.; Yoshida, K.; Yuda, T.

    2014-11-01

    The CALorimetric Electron Telescope (CALET) space experiment, currently under development by Japan in collaboration with Italy and the United States, will measure the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma rays to 10 TeV and nuclei with Z=1 to 40 up to 1,000 TeV during a two-year mission on the International Space Station (ISS), extendable to five years. These measurements are essential to search for dark matter signatures, investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy and discover possible astrophysical sources of high-energy electrons nearby the Earth. The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). CALET has sufficient depth, imaging capabilities and excellent energy resolution to allow for a clear separation between hadrons and electrons and between charged particles and gamma rays. The instrument will be launched to the ISS within 2014 Japanese Fiscal Year (by the end of March 2015) and installed on the Japanese Experiment Module-Exposed Facility (JEM-EF). In this paper, we will review the status and main science goals of the mission and describe the instrument configuration and performance.

  11. Algorithms for Identification of Nearly-Coincident Events in Calorimetric Sensors

    NASA Astrophysics Data System (ADS)

    Alpert, B.; Ferri, E.; Bennett, D.; Faverzani, M.; Fowler, J.; Giachero, A.; Hays-Wehle, J.; Maino, M.; Nucciotti, A.; Puiu, A.; Swetz, D.; Ullom, J.

    2015-12-01

    For experiments with high arrival rates, reliable identification of nearly-coincident events can be crucial. For calorimetric measurements to directly measure the neutrino mass such as HOLMES, unidentified pulse pile-ups are expected to be a leading source of experimental error. Although Wiener filtering can be used to recognize pile-up, it suffers from errors due to pulse shape variation from detector nonlinearity, readout dependence on subsample arrival times, and stability issues from the ill-posed deconvolution problem of recovering Dirac delta-functions from smooth data. Due to these factors, we have developed a processing method that exploits singular value decomposition to (1) separate single-pulse records from piled-up records in training data and (2) construct a model of single-pulse records that accounts for varying pulse shape with amplitude, arrival time, and baseline level, suitable for detecting nearly-coincident events. We show that the resulting processing advances can reduce the required performance specifications of the detectors and readout system or, equivalently, enable larger sensor arrays and better constraints on the neutrino mass.

  12. A calorimetric study of the hydrolysis and peroxide complex formation of the uranyl(VI) ion.

    PubMed

    Zanonato, Pier Luigi; Di Bernardo, Plinio; Grenthe, Ingmar

    2014-02-14

    The enthalpies of reaction for the formation of uranyl(vi) hydroxide {[(UO2)2(OH)2](2+), [(UO2)3(OH)4](2+), [(UO2)3(OH)5](+), [(UO2)3(OH)6](aq), [(UO2)3(OH)7](-), [(UO2)3(OH)8](2-), [(UO2)(OH)3](-), [(UO2)(OH)4](2-)} and peroxide complexes {[UO2(O2)(OH)](-) and [(UO2)2(O2)2(OH)](-)} have been determined from calorimetric titrations at 25 °C in a 0.100 M tetramethyl ammonium nitrate ionic medium. The hydroxide data have been used to test the consistency of the extensive thermodynamic database published by the Nuclear Energy Agency (I. Grenthe, J. Fuger, R. J. M. Konings, R. J. Lemire, A. B. Mueller, C. Nguyen-Trung and H. Wanner, Chemical Thermodynamics of Uranium, North-Holland, Amsterdam, 1992 and R. Guillaumont, T. Fanghänel, J. Fuger, I. Grenthe, V. Neck, D. J. Palmer and M. R. Rand, Update on the Chemical Thermodynamics of Uranium, Neptunium, Plutonium, Americium and Technetium, Elsevier, Amsterdam, 2003). A brief discussion is given about a possible structural relationship between the trinuclear complexes [(UO2)3(OH)n](6-n), n = 4-8. PMID:24301256

  13. The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

    NASA Astrophysics Data System (ADS)

    Adriani, O.; Akaike, Y.; Asano, K.; Asaoka, Y.; Bagliesi, M. G.; Bigongiari, G.; Binns, W. R.; Bonechi, S.; Bongi, M.; Buckley, J. H.; Castellini, G.; Cherry, M. L.; Collazuol, G.; Ebisawa, K.; Di Felice, V.; Fuke, H.; Guzik, T. G.; Hams, T.; Hareyama, M.; Hasebe, N.; Hibino, K.; Ichimura, M.; Ioka, K.; Israel, M. H.; Javaid, A.; Kamioka, E.; Kasahara, K.; Kataoka, J.; Kataoka, R.; Katayose, Y.; Kawanaka, N.; Kitamura, H.; Kotani, T.; Krawczynski, H. S.; Krizmanic, J. F.; Kubota, A.; Kuramata, S.; Lomtadze, T.; Maestro, P.; Marcelli, L.; Marrocchesi, P. S.; Mitchell, J. W.; Miyake, S.; Mizutani, K.; Moiseev, A. A.; Mori, K.; Mori, M.; Mori, N.; Motz, H. M.; Munakata, K.; Murakami, H.; Nakagawa, Y. E.; Nakahira, S.; Nishimura, J.; Okuno, S.; Ormes, J. F.; Ozawa, S.; Palma, F.; Papini, P.; Rauch, B. F.; Ricciarini, S. B.; Sakamoto, T.; Sasaki, M.; Shibata, M.; Shimizu, Y.; Shiomi, A.; Sparvoli, R.; Spillantini, P.; Takahashi, I.; Takayanagi, M.; Takita, M.; Tamura, T.; Tateyama, N.; Terasawa, T.; Tomida, H.; Torii, S.; Tunesada, Y.; Uchihori, Y.; Ueno, S.; Vannuccini, E.; Wefel, J. P.; Yamaoka, K.; Yanagita, S.; Yoshida, A.; Yoshida, K.; Yuda, T.

    2015-08-01

    The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF).

  14. The CALorimetric Electron Telescope (CALET) for high-energy astroparticle physics on the International Space Station

    NASA Astrophysics Data System (ADS)

    Adriani, O.; Akaike, Y.; Asano, K.; Asaoka, Y.; Bagliesi, M. G.; Bigongiari, G.; Binns, W. R.; Bonechi, S.; Bongi, M.; Buckley, J. H.; Castellini, G.; Cherry, M. L.; Collazuol, G.; Ebisawa, K.; Di Felice, V.; Fuke, H.; Guzik, T. G.; Hams, T.; Hareyama, M.; Hasebe, N.; Hibino, K.; Ichimura, M.; Ioka, K.; Israel, M. H.; Javaid, A.; Kamioka, E.; Kasahara, K.; Kataoka, J.; Kataoka, R.; Katayose, Y.; Kawanaka, N.; Kitamura, H.; Kotani, T.; Krawczynski, H. S.; Krizmanic, J. F.; Kubota, A.; Kuramata, S.; Lomtadze, T.; Maestro, P.; Marcelli, L.; Marrocchesi, P. S.; Mitchell, J. W.; Miyake, S.; Mizutani, K.; Moiseev, A. A.; Mori, K.; Mori, M.; Mori, N.; Motz, H. M.; Munakata, K.; Murakami, H.; Nakagawa, Y. E.; Nakahira, S.; Nishimura, J.; Okuno, S.; Ormes, J. F.; Ozawa, S.; Palma, F.; Papini, P.; Rauch, B. F.; Ricciarini, S. B.; Sakamoto, T.; Sasaki, M.; Shibata, M.; Shimizu, Y.; Shiomi, A.; Sparvoli, R.; Spillantini, P.; Takahashi, I.; Takayanagi, M.; Takita, M.; Tamura, T.; Tateyama, N.; Terasawa, T.; Tomida, H.; Torii, S.; Tunesada, Y.; Uchihori, Y.; Ueno, S.; Vannuccini, E.; Wefel, J. P.; Yamaoka, K.; Yanagita, S.; Yoshida, A.; Yoshida, K.; Yuda, T.

    2015-05-01

    The CALorimetric Electron Telescope (CALET) is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons) up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths) with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths) composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015) to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF).

  15. First calorimetric determination of heat of extraction of 248Cm in a bi-phasic system

    SciTech Connect

    Leigh R. Martin; Peter R. Zalupski

    2011-06-01

    This report presents a summary of the work performed to meet FCR&D level 2 milestone M21SW050201, 'Complete the first calorimetric determination of heat of extraction of 248Cm in a bi-phasic system'. This work was carried out under the auspices of the Thermodynamics and Kinetics FCR&D work package. To complement previous work undertaken under this work package we have extended out heat of extraction studies by di-2-ethyl-hexyl-phosphoric acid to curium. This report also details the heat of extraction of samarium in the same system. This work was performed to not only test the methodology but also to check for consistency with the heats of extraction obtained with those in the prior literature. The heat of extraction for samarium that was obtained in this study was -9.6 kJ mol-1, which is in reasonable agreement with the previously obtained value of -10.9 kJ mol-1. The curium heat of extraction was performed under two sets of conditions and the obtained heats of extraction were in reasonable agreement with each other at -16.0 {+-} 1.1 and -16.8 {+-} 1.5 kJ mol-1.

  16. Calorimetric measurement of electron energy deposition in extended media. Theory vs experiment

    SciTech Connect

    Lockwood, G.J.; Ruggles, L.E.; Miller, G.H.; Halbleib, J.A.

    1980-01-01

    A new calorimetric technique has been developed for measuring electron energy deposition profiles in one dimension. The experimental procedures and theoretical analyses required in the application of the new method are reviewed. Extensive results are presented for electron energy deposition profiles in semi-infinite homogeneous and multilayer configurations. These data cover a range of elements from beryllium through uranium at source energies from 0.3 to 1.0 MeV (selected data at 0.5 and 0.1 MeV) and at incident angles from 0/sup 0/ to 60/sup 0/. In every case, the experimental profiles are compared with the predictions of a coupled electron/photon Monte Carlo transport code. Overall agreement between theory and experiment is very good. However, there appears to be a tendency for the theoretical profiles to be higher near the peaks and lower near the tails, especially in high-Z materials. There is also a discrepancy between theory and experiment in low-Z materials near high-Z/low-Z interfaces.

  17. Electron energy and charge albedos - calorimetric measurement vs Monte Carlo theory

    SciTech Connect

    Lockwood, G.J.; Ruggles, L.E.; Miller, G.H.; Halbleib, J.A.

    1981-11-01

    A new calorimetric method has been employed to obtain saturated electron energy albedos for Be, C, Al, Ti, Mo, Ta, U, and UO/sub 2/ over the range of incident energies from 0.1 to 1.0 MeV. The technique was so designed to permit the simultaneous measurement of saturated charge albedos. In the cases of C, Al, Ta, and U the measurements were extended down to about 0.025 MeV. The angle of incidence was varied from 0/sup 0/ (normal) to 75/sup 0/ in steps of 15/sup 0/, with selected measurements at 82.5/sup 0/ in Be and C. In each case, state-of-the-art predictions were obtained from a Monte Carlo model. The generally good agreement between theory and experiment over this extensive parameter space represents a strong validation of both the theoretical model and the new experimental method. Nevertheless, certain discrepancies at low incident energies, especially in high-atomic-number materials, and at all energies in the case of the U energy albedos are not completely understood.

  18. Optical and Calorimetric Studies of Cholesterol-Rich Filamentous, Helical Ribbon and Crystal Microstructures

    SciTech Connect

    Miroshnikova, Y. A.; Elsenbeck, M.; Zastavker, Y. V.; Kashuri, K; Iannacchione, G. S.

    2009-04-19

    Formation of biological self-assemblies at all scales is a focus of studies in fields ranging from biology to physics to biomimetics. Understanding the physico-chemical properties of these self-assemblies may lead to the design of bio-inspired structures and technological applications. Here we examine self-assembled filamentous, helical ribbon, and crystal microstructures formed in chemically defined lipid concentrate (CDLC), a model system for cholesterol crystallization in gallbladder bile. CDLC consists of cholesterol, bilayer-forming amphiphiles, micelle-forming amphiphiles, and water. Phase contrast and differential interference contrast (DIC) microscopy indicate the presence of three microstructure types in all samples studied, and allow for an investigation of the structures' unique geometries. Additionally, confocal microscopy is used for qualitative assessment of surface and internal composition. To complement optical observations, calorimetric (differential-scanning and modulation) experiments, provide the basis for an in-depth understanding of collective and individual thermal behavior. Observed ''transition'' features indicate clustering and ''straightening'' of helical ribbons into short, increasingly thickening, filaments that dissolve with increasing temperature. These results suggest that all microstructures formed in CDLC may coexist in a metastable chemical equilibrium. Further investigation of the CDLC thermal profile should uncover the process of cholesterol crystallization as well as the unique design and function of microstructures formed in this system.

  19. Measurement and Modeling of Inner-Shell Satellites of Na-like Fe XVI between 14.5 Å and 18 Å

    SciTech Connect

    Graf, A; Beiersdorfer, P; Brown, G V; Gu, M F

    2007-09-10

    We have used the University of California Lawrence Livermore National Laboratory's EBIT-I electron beam ion trap to perform measurements of the wavelengths and relative intensities of the X-ray lines from inner-shell satellite transitions in sodium-like Fe XVI. The measurements were carried out with high-resolution crystal and grating spectrometers and covered the 14.5-18 {angstrom} wavelength band. Contrary to predicted line strengths and positions found in the literature, our results show that the strongest inner-shell satellites of Fe XVI are located near 15.2 {angstrom}. This is near the location of the 3d {yields} 2p intercombination line in Fe XVII. Calculations using the Flexible Atomic Code are presented, which agree well with the EBIT-I measurements.

  20. Collagen XVI Induces Expression of MMP9 via Modulation of AP-1 Transcription Factors and Facilitates Invasion of Oral Squamous Cell Carcinoma

    PubMed Central

    Bedal, Konstanze B.; Grssel, Susanne; Oefner, Peter J.; Reinders, Joerg; Reichert, Torsten E.; Bauer, Richard

    2014-01-01

    Collagen XVI belongs to the family of fibril-associated collagens with interrupted triple helices (FACIT). It is overexpressed during the progression of oral squamous cell carcinoma (OSCC). The present data show a strong collagen XVI-dependent induction of MMP9 and an increase in OSCC cell invasion. We found activated integrin-linked kinase (ILK) in a complex with kindlin-1 and activation of protein kinase B (PKB/Akt) to be responsible for MMP9 induction. Inhibition of the formation of focal adhesions reduced MMP9 expression. Moreover, collagen XVI overexpressing OSCC cell clones (COLXVI cell clones) transfected with vectors containing different MMP9 promoter fragments adjacent to a luciferase reporter revealed an increase in luciferase signal dependent on AP-1 binding sites. Deletion of the AP-1 binding site 98 bp upstream of the reported transcription start site and inhibition of AP-1 with Tanshinone IIA resulted in decreased MMP9 expression. The AP-1 subunit JunB showed differential expression between COLXVI cell clones and mock control cells. Additionally, mass spectrometric analysis of immunoprecipitates revealed that c-Fos interacted strongly with dyskerin in COLXVI cell clones compared to mock controls. PMID:24466237

  1. Calorimetric measurement of afterheat in target materials for the accelerator production of tritium

    SciTech Connect

    Perry, R.B.; Zucker, M.S.

    1994-06-01

    The estimate of afterheat in a spallation target of lead (Pb) or tungsten (W), by calorimetry, is the purpose of this experiment in support of the Accelerator Production of Tritium (APT). Such measurements are needed to confirm code calculations, these being the only practical way of gaining this type of information in a form suitable to aid the design of the APT machine. Knowledge of the magnitude and duration of afterheat resulting from decay of activation products produced by proton bombardment of the target is necessary to quantify APT safety assumptions, to design target cooling and safety systems, and to reduce technical risk. Direct calorimetric measurement of the afterheat for the appropriate incident proton energies is more reliable than the available alternative, which is indirect, based on data from gamma-ray spectroscopy measurements. The basic concept, a direct measurement of decay afterheat which bypasses the laborious classical way of determining this quantity, has been demonstrated to work. The gamma-ray energy given off by the decay products produced in the activation of lead or tungsten with high-energy protons apparently does represent a significant fraction of the total decay energy. A calorimeter designed for measurement of isotopes decaying by alpha emission must be modified to reduce energy lost with escaping gamma rays. Replacement of the aluminum liner with a tungsten liner in the SSC measurement chamber resulted in a 270% increase in measured heat, proving that the energy loss in the earlier (1992) measurements was significant. Gamma-ray measurements are needed to confirm the gamma-ray absorption calculations for the calorimeter to determine the correction for loss of heat due to transmission of high-energy gamma rays through the calorimeter walls. The experiments at BLIP have shown that calorimetry can be a useful tool in measuring the afterheat in APT target materials.

  2. Seasonal Variability in Calorimetric Energy Content of Two Caribbean Mesophotic Corals.

    PubMed

    Brandtneris, Viktor W; Brandt, Marilyn E; Glynn, Peter W; Gyory, Joanna; Smith, Tyler B

    2016-01-01

    Energetic responses of zooxanthellate reef corals along depth gradients have relevance to the refugia potential of mesophotic coral ecosystems (MCEs). Previous observations suggested that MCEs in the Caribbean are thermally buffered during the warmest parts of the year and occur within or just below the chlorophyll maximum, suggesting abundant trophic resources. However, it is not known if mesophotic corals can maintain constant energy needs throughout the year with changing environmental and biological conditions. The energetic content of tissues from the stony coral species Orbicella faveolata and Agaricia lamarcki was measured on the southern insular shelf of St. Thomas, US Virgin Islands (USVI), using micro-bomb calorimetry. Three sites for each species, at depths of 6m, 25m, 38m and 63m, were selected to capture energetic differences across the major vertical range extent of both species in the USVI-and sampled over five periods from April 2013 to April 2014. Mesophotic colonies of O. faveolata exhibited a significant reduction in energetic content during the month of September 2013 compared to mid-depth and shallow colonies (p = 0.032), whereas A. lamarcki experienced similar energetic variability, but with a significant reduction in energy content that occurred in July 2013 for colonies at sites deeper than 25m (p = 0.014). The results of calorimetric analyses indicate that O. faveolata may be at risk during late summer stress events, possibly due to the timing of reproductive activities. The low-point of A. lamarcki energy content, which may also coincide with reproduction, occurs prior to seasonal stress events, indicating contrasting, species-specific responses to environmental variability on MCEs. PMID:27050430

  3. Interaction of Antiinflammatory Drugs with EPC Liposomes: Calorimetric Study in a Broad Concentration Range

    PubMed Central

    Matos, Carla; Lima, José L. C.; Reis, Salette; Lopes, António; Bastos, Margarida

    2004-01-01

    Isothermal titration calorimetry was used to characterize and quantify the partition of indomethacin and acemetacin between the bulk aqueous phase and the membrane of egg phosphatidylcholine vesicles. Significant electrostatic effects were observed due to binding of the charged drugs to the membrane, which implied the use of the Gouy-Chapman theory to calculate the interfacial concentrations. The binding/partition phenomenon was quantified in terms of the partition coefficient (Kp), and/or the equilibrium constant (Kb). Mathematical expressions were developed, either to encompass the electrostatic effects in the partition model, or to numerically relate partition coefficients and binding constants. Calorimetric titrations conducted under a lipid/drug ratio >100:1 lead to a constant heat release and were used to directly calculate the enthalpy of the process, ΔH, and indirectly, ΔG and ΔS. As the lipid/drug ratio decreased, the constancy of reaction enthalpy was tested in the fitting process. Under low lipid/drug ratio conditions simple partition was no longer valid and the interaction phenomenon was interpreted in terms of binding isotherms. A mathematical expression was deduced for quantification of the binding constants and the number of lipid molecules associated with one drug molecule. The broad range of concentrations used stressed the biphasic nature of the interaction under study. As the lipid/drug ratio was varied, the results showed that the interaction of both drugs does not present a unique behavior in all studied regimes: the extent of the interaction, as well as the binding stoichiometry, is affected by the lipid/drug ratio. The change in these parameters reflects the biphasic behavior of the interaction—possibly the consequence of a modification of the membrane's physical properties as it becomes saturated with the drug. PMID:14747330

  4. Calorimetric studies of the kinetic unfreezing of molecular motions in hydrated lysozyme, hemoglobin, and myoglobin.

    PubMed Central

    Sartor, G; Mayer, E; Johari, G P

    1994-01-01

    Differential scanning calorimetric (DSC) studies of the glassy states of as-received and hydrated lysozyme, hemoglobin, and myoglobin powders, with water contents of < or = 0.25, < or = 0.30, and < or = 0.29 g/g of protein, show that their heat capacity slowly increases with increasing temperature, without showing an abrupt increase characteristic of glass-->liquid transition. Annealing (also referred to as physical aging) of the hydrated proteins causes their DSC scans to show an endothermic region, similar to an overshoot, immediately above the annealing temperature. This annealing effect appears at all temperatures between approximately 150 and 300 K. The area under these peaks increases with increasing annealing time at a fixed temperature. The effects are attributed to the presence of a large number of local structures in which macromolecular segments diffuse at different time scales over a broad range. The lowest time scale corresponds to the > N-H and -O-H group motions which become kinetically unfrozen at approximately 150-170 K on heating at a rate of 30 K min-1 and which have a relaxation time of 5-10 s in this temperature range. The annealing effects confirm that the individual glass transition of the relaxing local regions is spread over a temperature range up to the denaturation temperature region of the proteins. The interpretation is supported by simulation of DSC scans in which the distribution of relaxation times is assumed to be exceptionally broad and in which annealing done at several temperatures over a wide range produces endothermic effects (or regions of DSC scans) qualitatively similar to those observed for the hydrated proteins. PMID:8130342

  5. A high-temperature calorimetric flow sensor employing ion conduction in zirconia

    NASA Astrophysics Data System (ADS)

    Persson, A.; Lekholm, V.; Thornell, G.; Klintberg, L.

    2015-05-01

    This paper presents the use of the temperature-dependent ion conductivity of 8 mol % yttria-stabilized zirconia (YSZ8) in a miniature high-temperature calorimetric flow sensor. The sensor consists of 4 layers of high-temperature co-fired ceramic (HTCC) YSZ8 tape with a 400 μm wide, 100 μm deep, and 12 500 μm long internal flow channel. Across the center of the channel, four platinum conductors, each 80 μm wide with a spacing of 160 μm, were printed. The two center conductors were used as heaters, and the outer, up- and downstream conductors were used to probe the resistance through the zirconia substrate around the heaters. The thermal profile surrounding the two heaters could be made symmetrical by powering them independently, and hence, the temperature sensing elements could be balanced at zero flow. With nitrogen flowing through the channel, forced convection shifted the thermal profile downstream, and the resistance of the temperature sensing elements diverged. The sensor was characterized at nitrogen flows from 0 to 40 sccm, and resistances at zero-flow from 10 to 50 MΩ. A peak sensitivity of 3.1 MΩ/sccm was obtained. Moreover, the sensor response was found to be linear over the whole flow range, with R2 of around 0.999, and easy to tune with the individual temperature control of the heaters. The ability of the sensor to operate in high temperatures makes it promising for use in different harsh environments, e.g., for close integration with microthrusters.

  6. Seasonal Variability in Calorimetric Energy Content of Two Caribbean Mesophotic Corals

    PubMed Central

    Brandtneris, Viktor W.; Brandt, Marilyn E.; Glynn, Peter W.; Gyory, Joanna; Smith, Tyler B.

    2016-01-01

    Energetic responses of zooxanthellate reef corals along depth gradients have relevance to the refugia potential of mesophotic coral ecosystems (MCEs). Previous observations suggested that MCEs in the Caribbean are thermally buffered during the warmest parts of the year and occur within or just below the chlorophyll maximum, suggesting abundant trophic resources. However, it is not known if mesophotic corals can maintain constant energy needs throughout the year with changing environmental and biological conditions. The energetic content of tissues from the stony coral species Orbicella faveolata and Agaricia lamarcki was measured on the southern insular shelf of St. Thomas, US Virgin Islands (USVI), using micro-bomb calorimetry. Three sites for each species, at depths of 6m, 25m, 38m and 63m, were selected to capture energetic differences across the major vertical range extent of both species in the USVI—and sampled over five periods from April 2013 to April 2014. Mesophotic colonies of O. faveolata exhibited a significant reduction in energetic content during the month of September 2013 compared to mid-depth and shallow colonies (p = 0.032), whereas A. lamarcki experienced similar energetic variability, but with a significant reduction in energy content that occurred in July 2013 for colonies at sites deeper than 25m (p = 0.014). The results of calorimetric analyses indicate that O. faveolata may be at risk during late summer stress events, possibly due to the timing of reproductive activities. The low-point of A. lamarcki energy content, which may also coincide with reproduction, occurs prior to seasonal stress events, indicating contrasting, species-specific responses to environmental variability on MCEs. PMID:27050430

  7. Head-group contributions to bilayer stability: monolayer and calorimetric studies on synthetic, stereochemically uniform glucolipids.

    PubMed

    Hinz, H J; Six, L; Ruess, K P; Liefländer, M

    1985-01-29

    Monolayer and differential scanning calorimetry studies have been performed on synthetic, stereochemically uniform glyceroglucolipids having saturated, ether-linked alkyl chains. The limiting area, A0 = 40 A2 X molecule-1, resulting from the monolayer measurements of the glucolipids is comparable to the A0 value found for phosphatidylethanolamine lipids. The area corresponds to twice the value observed with saturated straight chain fatty acids, which indicates that at high surface pressure the space requirement of the glucose head group does not exceed that of the two alkyl chains. The apparent specific heat capacities of the glucolipid dispersions have been found to be higher than those of corresponding phospholipids. They can be approximated from group parameters with the additional assumption that the experimental partial molar heat capacity of glucose is valid for the glucose head groups of the lipids. The transition enthalpies of the C16 and C18 glyceroglucolipids are clearly larger than the delta H values of corresponding phospholipids, while the C14 glyceroglucolipid has the same transition enthalpy as dimyristoylphosphatidylethanolamine or ditetradecylphosphatidylethanolamine. Glucolipids exhibit gel to liquid-crystalline phase transition temperatures which are only slightly lower than those of their phosphatidylethanolamine analogues, although they are uncharged molecules. Like phosphatidylethanolamine the glucolipids do not show a pretransition; however, with the C14 glucolipid a highly cooperative posttransition, approximately 5 deg above the main transition, has been found. Calorimetric experiments with a C14 glucolipid, in which the hydroxyl protons of the glucose moiety have been exchanged by deuterium, suggest that the posttransition might reflect structural changes of the head group.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3994987

  8. Compound matrices

    NASA Astrophysics Data System (ADS)

    Kravvaritis, Christos; Mitrouli, Marilena

    2009-02-01

    This paper studies the possibility to calculate efficiently compounds of real matrices which have a special form or structure. The usefulness of such an effort lies in the fact that the computation of compound matrices, which is generally noneffective due to its high complexity, is encountered in several applications. A new approach for computing the Singular Value Decompositions (SVD's) of the compounds of a matrix is proposed by establishing the equality (up to a permutation) between the compounds of the SVD of a matrix and the SVD's of the compounds of the matrix. The superiority of the new idea over the standard method is demonstrated. Similar approaches with some limitations can be adopted for other matrix factorizations, too. Furthermore, formulas for the n - 1 compounds of Hadamard matrices are derived, which dodge the strenuous computations of the respective numerous large determinants. Finally, a combinatorial counting technique for finding the compounds of diagonal matrices is illustrated.

  9. Crop changes from the XVI century to the present in a hill/mountain area of eastern Liguria (Italy)

    PubMed Central

    Gentili, Rodolfo; Gentili, Elio; Sgorbati, Sergio

    2009-01-01

    Background Chronological information on the composition and structure of agrocenoses and detailed features of land cover referring to specific areas are uncommon in ethnobotanical studies, especially for periods before the XIX century. The aim of this study was to analyse the type of crop or the characteristics of soil cover from the XVI century to the present. Methods This diachronic analysis was accomplished through archival research on the inventories of the Parish of St. Mary and those of the Municipality of Pignone and from recent surveys conducted in an area of eastern Liguria (Italy). Results Archival data revealed that in study area the primary means of subsistence during the last five centuries, until the first half of the XX century, was chestnuts. In the XVIII and XIX centuries, crop diversification strongly increased in comparison with previous and subsequent periods. In more recent times, the abandonment of agricultural practices has favoured the re-colonisation of mixed woodland or cluster-pine woodland. Conclusion Ancient documents in the ecclesiastic or municipal inventories can be a very useful tool for enhancing the knowledge of agricultural practice, as well as of subsistence methods favoured by local populations during a particular time and for reconstructing land use change over time. PMID:19361339

  10. Analbite - Sanidine Thermodynamic Mixing Properties: Highly Precise HF Solution Calorimetric Data Across A Twenty-Member Crystalline Solution Series

    NASA Astrophysics Data System (ADS)

    Hovis, G. L.

    2013-12-01

    Enthalpies of K-Na mixing for the analbite - sanidine feldspar series were investigated by Hovis (1988, J. Petrology) in the early 80's. That work was based on data at a limited number of compositions, owing to the large sample sizes required for HF solution calorimetric measurements at the time. Thermodynamic mixing properties for mineral series, especially those exhibiting compositionally asymmetric mixing quantities, are best defined when samples at a large number of compositions are utilized. Enabled by the small sample sizes now possible for HF solution calorimetric dissolutions (Hovis et al., 1998, Amer. Mineral.), we revisit feldspar thermodynamic properties, having synthesized an analbite - sanidine series consisting of samples at 20 compositions. Solution calorimetric experiments on these samples at 50 °C in 20.1 wt% HF under isoperibolic conditions have resulted in highly precise calorimetric data (standard deviation per sample averaging 0.06 % of the heat of solution). Although enthalpies of K-Na mixing based on the new data display some degree of compositional asymmetry, with a maximum value of 4.8 kJ/mol at a mole fraction potassium of 0.47, the distribution of enthalpy-of-mixing values remains nearly symmetric with respect to K content. This contrasts significantly with data for Al-Si ordered low albite - microcline crystalline solutions, reinvestigated via synthesis of a 21-member series, which show significantly higher mixing magnitudes and considerably greater asymmetry with respect to composition. The maximization of enthalpies of K-Na mixing at sodic compositions correlates well with the sodic critical compositions for both solvi. The lower mixing magnitudes for analbite - sanidine are consistent with the comparatively lower critical temperature of the analbite - sanidine solvus (e.g., Smith & Parsons, 1974, Mineral. Mag.) relative to that for low albite - microcline (Bachinski & Müller, 1971, J. Petrology). Entropies of K-Na mixing for analbite - sanidine have been calculated by combining present enthalpy data with Gibbs free energies of mixing derived from the earlier phase equilibrium study of Hovis et al. (1991, Amer. Mineral.). These may be compared with directly measured entropy data for analbite - sanidine based on the heat capacity measurements of Haselton et al. (1983, Amer. Mineral.). Thanks to the National Science Foundation for funding this research.

  11. Analbite - Sanidine Thermodynamic Mixing Properties: Highly Precise HF Solution Calorimetric Data Across A Twenty-Member Crystalline Solution Series

    NASA Astrophysics Data System (ADS)

    Hovis, G. L.

    2012-12-01

    Enthalpies of K-Na mixing for the analbite - sanidine feldspar series were investigated by Hovis (1988, J. Petrology) in the early 80's. That work was based on data at a limited number of compositions, owing to the large sample sizes required for HF solution calorimetric measurements at the time. Thermodynamic mixing properties for mineral series, especially those exhibiting compositionally asymmetric mixing quantities, are best defined when samples at a large number of compositions are utilized. Enabled by the small sample sizes now possible for HF solution calorimetric dissolutions (Hovis et al., 1998, Amer. Mineral.), we revisit feldspar thermodynamic properties, having synthesized an analbite - sanidine series consisting of samples at 20 compositions. Solution calorimetric experiments on these samples at 50 °C in 20.1 wt% HF under isoperibolic conditions have resulted in highly precise calorimetric data (standard deviation per sample averaging 0.06 % of the heat of solution). Although enthalpies of K-Na mixing based on the new data display some degree of compositional asymmetry, with a maximum value of 4.8 kJ/mol at a mole fraction potassium of 0.47, the distribution of enthalpy-of-mixing values remains nearly symmetric with respect to K content. This contrasts significantly with data for Al-Si ordered low albite - microcline crystalline solutions, reinvestigated via synthesis of a 21-member series, which show significantly higher mixing magnitudes and considerably greater asymmetry with respect to composition. The maximization of enthalpies of K-Na mixing at sodic compositions correlates well with the sodic critical compositions for both solvi. The lower mixing magnitudes for analbite - sanidine are consistent with the comparatively lower critical temperature of the analbite - sanidine solvus (e.g., Smith & Parsons, 1974, Mineral. Mag.) relative to that for low albite - microcline (Bachinski & Müller, 1971, J. Petrology). Entropies of K-Na mixing for analbite - sanidine have been calculated by combining present enthalpy data with Gibbs free energies of mixing derived from the earlier phase equilibrium study of Hovis et al. (1991, Amer. Mineral.). These may be compared with directly measured entropy data for analbite - sanidine based on the heat capacity measurements of Haselton et al. (1983, Amer. Mineral.).

  12. Investigation of a zirconia co-fired ceramic calorimetric microsensor for high-temperature flow measurements

    NASA Astrophysics Data System (ADS)

    Lekholm, Ville; Persson, Anders; Klintberg, Lena; Thornell, Greger

    2015-06-01

    This paper describes the design, fabrication and characterization of a flow sensor for high-temperature, or otherwise aggressive, environments, like, e.g. the propulsion system of a small spacecraft. The sensor was fabricated using 8 mol% yttria stabilized zirconia (YSZ8) high-temperature co-fired ceramic (HTCC) tape and screen printed platinum paste. A calorimetric flow sensor design was used, with five 80 µm wide conductors, separated by 160 µm, in a 0.4 mm wide, 0.1 mm deep and 12.5 mm long flow channel. The central conductor was used as a heater for the sensor, and the two adjacent conductors were used to resistively measure the heat transferred from the heater by forced convection. The two outermost conductors were used to study the influence of an auxiliary heat source on the sensor. The resistances of the sensor conductors were measured using four-point connections, as the gas flow rate was slowly increased from 0 to 40 sccm, with different power supplied through the central heater, as well as with an upstream or downstream heater powered. In this study, the thermal and electrical integrability of microcomponents on the YSZ8 substrate was of particular interest and, hence, the influence of thermal and ionic conduction in the substrate was studied in detail. The effect of the ion conductivity of YSZ8 was studied by measuring the resistance of a platinum conductor and the resistance between two adjacent conductors on YSZ8, in a furnace at temperatures from 20 to 930 °C and by measuring the resistance with increasing current through a conductor. With this design, the influence of ion conductivity through the substrate became apparent above 700 °C. The sensitivity of the sensor was up to 1 mΩ sccm-1 in a range of 0-10 sccm. The results show that the signal from the sensor is influenced by the integrated auxiliary heating conductors and that these auxiliary heaters provide a way to balance disturbing heat sources, e.g. thrusters or other electronics, in conjunction with the flow sensor.

  13. Raman spectra of gases. XVI - Torsional transitions in ethanol and ethanethiol

    NASA Technical Reports Server (NTRS)

    Durig, J. R.; Bucy, W. E.; Wurrey, C. J.; Carreira, L. A.

    1975-01-01

    The Raman spectra of gaseous ethanol and ethanethiol have been investigated. Thiol torsional fundamentals for the gauche conformer of EtSH and EtSD have been observed and the asymmetric potential function for this vibration has been calculated. Methyl torsional transitions and overtones have also been observed for both of these molecules. Barriers to internal rotation for the methyl top are calculated to be 3.77 and 3.84 kcal/mol for the EtSH and EtSD compounds, respectively. Hydroxyl torsional fundamentals were observed at 207 and 170 per cm in the EtOH and EtOD spectra, respectively. Overtones of the methyl torsion in both molecules yield a barrier to internal rotation of 3.62 kcal/mol for the gauche conformer.

  14. The Path of Carbon in Photosynthesis XVI. Kinetic Relationships of the Intermediates in Steady State Photosynthesis

    DOE R&D Accomplishments Database

    Benson, A. A.; Kawaguchi, S.; Hayes, P.; Calvin, M.

    1952-06-05

    A kinetic study of the accumulation of C{sup 14} in the intermediates of steady state photosynthesis in C{sup 14}O{sub 2} provides information regarding the sequence of reactions involved. The work described applied the radio-chromatographic technique for analysis of the labeled early products. The simultaneous carboxylation reaction resulting in malic acid as well as phosphoglycerate is demonstrated in experiments at high light intensity. A comparison of radioactivities in a number of phosphorylated sugars as a function of time reveals concurrent synthesis of fructose and sedoheptulose phosphates followed by that of ribulose phosphates and later by that of glucose phosphates. The possibility that the cleavage of C{sub 4} compounds to C{sub 2} carbon dioxide acceptors may involve C{sub 7} and C{sub 5} sugars and evidence for this mechanism is presented.

  15. Development of Metallic Magnetic Calorimeters for High Precision Measurements of Calorimetric Re-187 and Ho-163 Spectra

    NASA Technical Reports Server (NTRS)

    Ranitzsch, P. C.-O.; Porst, J.-P.; Kempf, S.; Pies, C.; Schafer, S.; Hengstler, D.; Fleischmann, A.; Enss, C.; Gastaldo, L.

    2012-01-01

    The measurement of calorimetric spectra following atomic weak decays, beta (b) and electron capture (EC), of nuclides having a very low Q-value, can provide an impressively high sensitivity to a non-vanishing neutrino mass. The achievable sensitivity in this kind of experiments is directly connected to the performance of the used detectors. In particular an energy resolution of a few eV and a pulse formation time well below 1 microsecond are required. Low temperature Metallic Magnetic Calorimeters (MMCs) for soft X-rays have already shown an energy resolution of 2.0 eV FWHM and a pulse rise-time of about 90 ns for fully micro-fabricated detectors. We present the use of MMCs for high precision measurements of calorimetric spectra following the beta-decay of Re-187 and the EC of Ho-163. We show results obtained with detectors optimized for Re-187 and for Ho-163 experiments respectively. While the detectors equipped with superconducting Re absorbers have not yet reached the aimed performance, a first detector prototype with a Au absorber having implanted Ho-163 ions already shows excellent results. An energy resolution of 12 eV FWHM and a rise time of 90 ns were measured.

  16. Quantitative schlieren diagnostics for the determination of ambient species density, gas temperature and calorimetric power of cold atmospheric plasma jets

    NASA Astrophysics Data System (ADS)

    Schmidt-Bleker, A.; Reuter, S.; Weltmann, K.-D.

    2015-05-01

    A measurement and evaluation technique for performing quantitative Schlieren diagnostics on an argon-operated cold atmospheric plasma jet is presented. Combined with computational fluid dynamics simulations, the method not only yields the temporally averaged ambient air density and temperature in the effluent of the fully turbulent jet, but also allows for an estimation of the calorimetric power deposited by the plasma. The change of the refractive index due to mixing of argon and air is in the same range as caused by the temperature increase of less than 35 K in the effluent of the plasma jet. The Schlieren contrast therefore needs to be corrected for the contribution from ambient air diffusion. The Schlieren system can be calibrated accurately using the signal obtained from the argon flow when the plasma is turned off. The temperature measured in this way is compared to the value obtained using a fibre-optics temperature probe and shows excellent agreement. By fitting a heat source in a fluid dynamics simulation to match the measured temperature field, the calorimetric power deposited by the plasma jet can be estimated as 1.1 W.

  17. Emission Line Spectra from Fe VII to XVI in the Soft X-ray and Extreme Ultraviolet

    NASA Astrophysics Data System (ADS)

    Lepson, J. K.; Beiersdorfer, P.; Brown, G. V.; Kahn, S. M.; Liedahl, D. A.; Utter, S. B.

    2000-10-01

    Stellar coronae are rich emitters of iron radiation in the soft x-ray and EUV. This spectral region has been opened up first by the EUV Explorer and now by the Chandra X-ray Observatory for detailed observations with high resolution. Lines in this region are a valuable diagnostic tool for temperature and density, but accurate analysis and interpretation requires accurate spectral models and data. We have shown in previous laboratory measurements that the line lists available for the low charge states of iron, especially Fe VII through Fe XIII are strikingly incomplete. Many of the lines left out in the line lists are weak, but because there are many of them, a substantial amount of spectral flux (more than 50%) is missing. Incomplete accounting of these lines can have marked consequences when modeling the coronae of cool stars, such as α Cen, both by underestimating the flux of the lowest iron charge states and by incorrect assignments of the base level of those strong lines that sit on top of the flux caused by many unresolved weak lines. We are addressing this problem by using the unique spectroscopic abilities of the Lawrence Livermore Electron Beam Ion Trap to compile a catalogue of the relevant line emission in the soft x-ray and EUV region. As part of this catalogue we present here spectra and line lists for Fe VII - Fe XVI between 50-140 Å. Our line lists include wavelengths and line intensities that allow us to estimate the contributions from unresolved lines relative to those of known lines from the same charge state. We also compare these line lists and spectra with the MeKa and CHIANTI models and HULLAC calculations.

  18. Investigation of the accuracy of MV radiation isocentre calculations in the Elekta cone-beam CT software XVI.

    PubMed

    Riis, Hans L; Moltke, Lars N; Zimmermann, Sune J; Ebert, Martin A; Rowshanfarzad, Pejman

    2016-06-01

    Accurate determination of the megavoltage (MV) radiation isocentre of a linear accelerator (linac) is an important task in radiotherapy. The localization of the MV radiation isocentre is crucial for correct calibration of the in-room lasers and the cone-beam CT scanner used for patient positioning prior to treatment. Linac manufacturers offer tools for MV radiation isocentre localization. As a user, there is no access to the documentation for the underlying method and calculation algorithm used in the commercial software. The idea of this work was to evaluate the accuracy of the software tool for MV radiation isocentre calculation as delivered by Elekta using independent software. The image acquisition was based on the scheme designed by the manufacturer. Eight MV images were acquired in each series of a ball-bearing (BB) phantom attached to the treatment couch. The images were recorded at cardinal angles of the gantry using the electronic portal imaging device (EPID). Eight Elekta linacs with three different types of multileaf collimators (MLCs) were included in the test. The influence of MLC orientation, x-ray energy, and phantom modifications were examined. The acquired images were analysed using the Elekta x-ray volume imaging (XVI) software and in-house developed (IHD) MATLAB code. Results from the two different software were compared. A discrepancy in the longitudinal direction of the isocentre localization was found averaging 0.23 mm up to a maximum of 0.75 mm. The MLC orientation or the phantom asymmetry in the longitudinal direction do not appear to cause the discrepancy. The main cause of the differences could not be clearly identified. However, it is our opinion that the commercial software delivered by the linac manufacturer should be improved to reach better stability and precise results in the MV radiation isocentre calculations. PMID:27183466

  19. Geant4 simulation of the Elekta XVI kV CBCT unit for accurate description of potential late toxicity effects of image-guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Brochu, F. M.; Burnet, N. G.; Jena, R.; Plaistow, R.; Parker, M. A.; Thomas, S. J.

    2014-12-01

    This paper describes the modelisation of the Elekta XVI Cone Beam Computed Tomography (CBCT) machine components with Geant4 and its validation against calibration data taken for two commonly used machine setups. Preliminary dose maps of simulated CBCTs coming from this modelisation work are presented. This study is the first step of a research project, GHOST, aiming to improve the understanding of late toxicity risk in external beam radiotherapy patients by simulating dose depositions integrated from different sources (imaging, treatment beam) over the entire treatment plan. The second cancer risk will then be derived from different models relating irradiation dose and second cancer risk.

  20. Absorption of organic compounds and organometallics on ceramic substrates for wear reduction

    SciTech Connect

    Kennedy, P.J.; Agarwala, V.S.

    1996-12-31

    The concept of employing thermally stable compounds (that is, metal oxides) as high temperature vapor phase ceramic lubricants was investigated. A major part of this study was devoted to the development of various calorimetric and tribological techniques that could be used to determine interfacial reactions between thermally stable compounds and ceramic substrates such as zirconia and alumina. This interaction is pivotal in understanding the mechanism of high temperature lubricity. The approach consisted of selecting low sublimation temperature materials and measuring their thermodynamic interactions as vapors with the ceramic substrates. The materials studied included two easily sublimable organic compounds (that is, naphthalene and salicylic acid) and several organometallics (for example, copper phthalocyanine). Thermodynamic data such as heat of adsorption, packing density, and reversibility of the adsorption were obtained on some of these compounds and were related to wear characteristics. All of these compounds provided effective lubrication at room temperature. Copper phthalocyanine was an effective lubricant at temperatures up to 400 C.

  1. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  2. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.; Jones, Michael G.; Wertsching, Alan K.; Luther, Thomas A.; Trowbridge, Tammy L.

    2011-11-22

    A PBI compound includes imidazole nitrogens at least a portion of which are substituted with a moiety containing a carbonyl group, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. At least 85% of the nitrogens may be substituted. The carbonyl-containing moiety may include RCO--, where R is alkoxy or haloalkyl. The PBI compound may exhibit a first temperature marking an onset of weight loss corresponding to reversion of the substituted PBI that is less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may use more than 5 equivalents in relation to the imidazole nitrogens to be substituted.

  3. MEASUREMENT AND MODELING OF Na-LIKE Fe XVI INNER-SHELL SATELLITES BETWEEN 14.5 A AND 18 A

    SciTech Connect

    Graf, A.; Beiersdorfer, P.; Brown, G. V.; Gu, M. F.

    2009-04-20

    We have used the University of California Lawrence Livermore National Laboratory's EBIT-I electron beam ion trap to perform measurements of the wavelengths and relative intensities of the X-ray lines from inner-shell satellite transitions in sodium-like Fe XVI. The measurements were carried out with high-resolution crystal and grating spectrometers and covered the 14.5-18 A wavelength band. In contrast to some predicted line strengths and positions found in the literature, our results show that the strongest relatively unblended inner-shell satellites of Fe XVI are located near 15.2 A. This is near the location of the 3d{yields} 2p intercombination line in Fe XVII. Calculations using the Flexible Atomic Code (FAC) are presented. The average deviation between the EBIT-I measurements and the FAC calculations for the wavelength positions and line ratios are 22 mA and a factor of 2.3, respectively, where the average is taken over the ten features included in this work.

  4. Calorimetric analysis of the two way memory effect in a NiTi alloy -- Experiments and calculations

    SciTech Connect

    Silva, E.P. da

    1999-04-23

    In addition to the well known one-way memory effect in heating, some shape memory alloys may also exhibit a shape recovery upon cooling, i.e. they show the two-way memory effect (TWME). This is not an inherent property of such alloys, and to obtain it, the alloy must be trained. Besides the two-way memory effect, the training processes can also cause changes such as a shift of the transformation temperatures. In this work a calorimetric investigation of a one-way and two-way NiTi memory alloy is presented. The heat flow was measured by use of a Differential Scanning Calorimeter. The differences in the temperatures and enthalpy of transformations between one-way and two-way memory samples are presented, compared and discussed. A mathematical prediction of the heat and temperatures of transformation is presented.

  5. Evaluation of the Thermodynamic Functions for Aqueous Sodium Chloride from Equilibrium and Calorimetric Measurements below 154 °C

    NASA Astrophysics Data System (ADS)

    Clarke, E. Colin W.; Glew, David N.

    1985-04-01

    A new weighted least-squares method is described which is generally applicable for the nonsubjective evaluation of the best set of thermodynamic functions from a given data set of equilibrium (ΔG) and calorimetric (ΔH, Cp) measurements. The method, applied to model a wide range of 2428 measurements for the water-sodium chloride system between -21 and 154 °C, accurately represents all measurements within experimental error. The resulting model is used to predict the thermodynamic functions and their standard errors for aqueous sodium chloride up to 110 °C. Tables are given for freezing point, solubility, boiling point, osmotic and activity coefficients, vapor pressure, apparent molal relative enthalpy, partial molal relative enthalpies, integral heat of solution, specific heat, apparent molal heat capacity, partial molal heat capacities, apparent molal relative heat capacity, partial molal relative heat capacities, standard thermodynamic functions, and their changes for dissolution.

  6. A micromachined calorimetric gas sensor: an application of electrodeposited nanostructured palladium for the detection of combustible gases.

    PubMed

    Bartlett, Philip N; Guerin, Samuel

    2003-01-01

    Palladium films with regular nanoarchitectures were electrochemically deposited from the hexagonal (H1) lyotropic liquid crystalline phase of the nonionic surfactant octaethyleneglycol monohexadecyl ether (C16EO8) onto micromachined silicon hotplate structures. The H1-e Pd films were shown to have high surface areas (approximately 28 m2 g(-1)) and to act as effective and stable catalysts for the detection of methane in air on heating to 500 degrees C. The response of the H1-e Pd-coated planar pellistors was found to be linearly proportional to the concentration of methane between 0 and 2.5% in air with a detection limit below 0.125%. Our results show that the electrochemical deposition of nanostructured metal films offers a promising approach to the fabrication of micromachined calorimetric gas sensors for combustible gases. PMID:12530828

  7. Comparative dose evaluations between XVI and OBI cone beam CT systems using Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters

    SciTech Connect

    Giaddui, Tawfik; Cui Yunfeng; Galvin, James; Yu Yan; Xiao Ying

    2013-06-15

    Purpose: To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (XVI) (Version R4.5) and on board imager (OBI) (Version 1.5) CBCT imaging protocols using these two types of dosimeters. Methods: Gafchromic XRQA2 film and nanoDot OSLD dose response curves were generated at different kV imaging settings used by XVI (software version R4.5) and OBI (software version 1.5) CBCT systems. The settings for the XVI system were: 100 kVp/F0 (no filter), 120 kVp/F0, and 120 kVp/F1 (Bowtie filter), and for the OBI system were: 100 kVp/full fan, 125 kVp/full fan, and 125 kVp/half fan. XRQA2 film was calibrated in air to air kerma levels between 0 and 11 cGy and scanned using reflection scanning mode with the Epson Expression 10000 XL flat-bed document scanner. NanoDot OSLDs were calibrated on phantom to surface dose levels between 0 and 14 cGy and read using the inLight{sup TM} MicroStar reader. Both dosimeters were used to measure in field surface and internal doses in a male Alderson Rando Phantom. Results: Dose response curves of XRQA2 film and nanoDot OSLDs at different XVI and OBI CBCT settings were reported. For XVI system, the surface dose ranged between 0.02 cGy in head region during fast head and neck scan and 4.99 cGy in the chest region during symmetry scan. On the other hand, the internal dose ranged between 0.02 cGy in the head region during fast head and neck scan and 3.17 cGy in the chest region during chest M20 scan. The average (internal and external) dose ranged between 0.05 cGy in the head region during fast head and neck scan and 2.41 cGy in the chest region during chest M20 scan. For OBI system, the surface dose ranged between 0.19 cGy in head region during head scan and 4.55 cGy in the pelvis region during spot light scan. However, the internal dose ranged between 0.47 cGy in the head region during head scan and 5.55 cGy in the pelvis region during spot light scan. The average (internal and external) dose ranged between 0.45 cGy in the head region during head scan and 3.59 cGy in the pelvis region during spot light scan. Both Gafchromic XRQA2 film and nanoDot OSLDs gave close estimation of dose (within uncertainties) in many cases. Though, discrepancies of up to 20%-30% were observed in some cases. Conclusions: Dose response curves of Gafchromic XRQA2 film and nanoDot OSLDs indicated that the dose responses of these two dosimeters were different even at the same photon energy when different filters were used. Uncertainty levels of both dosimetry systems were below 6% at doses above 1 cGy. Both dosimetry systems gave almost similar estimation of doses (within uncertainties) in many cases, with exceptions of some cases when the discrepancy was around 20%-30%. New versions of the CBCT systems (investigated in this study) resulted in lower imaging doses compared with doses reported on earlier versions in previous studies.

  8. Temperature-dependent infrared and calorimetric studies on arsenicals adsorption from solution to hematite nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To address the lack of systematic and surface sensitive studies on the adsorption energetics of arsenic compounds on metal (oxyhydr)oxides, we conducted temperature-dependent ATR-FTIR studies for the adsorption of arsenate, monomethylarsonic acid, and dimethylarsinic acid on hematite nanoparticles a...

  9. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

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

  10. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  11. Perfluorinated compounds.

    PubMed

    Lau, Christopher

    2012-01-01

    Perfluorinated compounds such as the perfluoroalkyl acids (PFAAs) and their derivatives are important man-made chemicals that have wide consumer and industrial applications. They are relatively contemporary chemicals, being in use only since the 1950s and until recently have been considered as biologically inactive. However, during the past decade, their global distribution, environmental persistence, presence in humans and wildlife, and adverse health effects in laboratory animals have come to light, generating scientific, regulatory, and public interest on an international scale. This chapter will provide a brief overview of recent advances in understanding environmental and human exposure, toxicology, and modes of action for this class of compounds in animal models, as well as a summary of epidemiological findings to date. PMID:22945566

  12. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  13. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  14. A Calorimetric Study of Almandine: Are the Thermodynamic Properties of the End-Member Aluminosilicate Garnets Finally Known Quantitatively?

    NASA Astrophysics Data System (ADS)

    Dachs, E.; Geiger, C. A.; Benisek, A.

    2012-12-01

    The aluminosilicate garnets (E3Al2Si3O12 with E = Fe2+, Mn2+, Ca, Mg) form an important rock-forming mineral group. Much study has been directed toward determining their thermodynamic properties. The iron end-member almandine (Fe3Al2Si3O12) is a key phase in many petrologic investigations. As part of an ongoing calorimetric and thermodynamic study of the aluminosilicate garnets, the heat capacity of three synthetic well-characterized polycrystalline almandine garnets and one natural almandine-rich single crystal was measured. The various garnets were characterized by optical microscopy, electron-microprobe analysis, X-ray powder diffraction and 57Fe Mössbauer spectroscopy. Heat capacity measurements were performed in the temperature range 3 to 300 K using relaxation calorimetry and between 282 and 764 K using DSC methods. From the former, So values between 336.7 ± 0.8 and 337.8 ± 0.8 J/molK are calculated for the different samples. The smaller value is considered the best So for end-member stoichiometric almandine, because it derives from the "best" Fe3+-free synthetic sample. The Cp behavior for almandine at T > 298 K is given by the polynomial (in J/molK): Cp = 649.06(±4) - 3837.57(±122)T-0.5 - 1.44682(±0.06)107T-2 + 1.94834(±0.09)109T-3, which is calculated using DSC data together with one published heat-content datum determined by transposed-drop calorimetry along with a new determination that gives H1181K - H302K = 415.0 ± 3.2 kJ/mole. Almandine shows a λ-type heat-capacity anomaly at low temperatures resulting from a paramagnetic-antiferromagnetic phase transition at about 9 K. The lattice heat capacity was calculated using the single-parameter phonon dispersion model of Komada and Westrum (1997), which allows the non-lattice heat capacity (Cex) behavior to be modelled. An analysis shows the presence of an electronic heat-capacity contribution (Cel - Schottky anomaly) around 17 K that is superimposed on a larger magnetic heat-capacity effect (Cmag). The calculated lattice entropy at 298.15 K is Svib = 303.3 J/molK and it contributes about 90% to the total standard entropy at 298 K. The non-lattice entropy is Sex = 33.4 J/molK and consists of Smag = 32.1 J/molK and Sel = 1.3 J/molK contributions. Using the So = 336.7 J/molK value and the Cp polynomial for almandine, we derived its enthalpy of formation, ΔHof, from an analysis of experimental phase equilibrium results on the reactions almandine + 3rutile = 3ilmenite + sillimanite + 2quartz and 2ilmenite = 2iron + 2rutile + O2. ΔHof = -5269.63 kJ/mol was obtained. So for grossular, pyrope, spessartine, and almandine, as well as their Cp behavior to high temperatures, have all been measured calorimetrically. Uncertainties in older calorimetric studies appear to have been resolved. The standard thermodynamic properties Vo and So are now well determined for all four garnets. In addition, ΔHof for all, except possibly spessartine, also appear to be well known.

  15. New methodology for simultaneous volumetric and calorimetric measurements: Direct determination of {alpha}{sub p} and C{sub p} for liquids under pressure

    SciTech Connect

    Casas, L. M.

    2009-12-15

    A new batch cell has been developed to measure simultaneously both isobaric thermal expansion and isobaric heat capacity from calorimetric measurements. The isobaric thermal expansion is directly proportional to the linear displacement of an inner flexible below and the heat capacity is calculated from the calorimetric signal. The apparatus used was a commercial Setaram C-80 calorimeter and together with this type of vessels can be operated up to 20 MPa and in the temperature range of 303.15-523.15 K, In this work, calibration was carried out using 1-hexanol and subsequently both thermophysical properties were determined for 3-pentanol, 3-ethyl-3-pentanol, and 1-octanol at atmospheric pressure, 5 and 10 MPa, and from 303.15 to 423.15 K in temperature. Finally experimental values were compared with the literature in order to validate this new methodology, which allows a very accurate determination of isobaric thermal expansion and isobaric heat capacity.

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  17. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  18. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  19. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

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

  20. Thermodynamics of H in disordered Pd-Ag alloys from calorimetric and equilibrium pressure-composition-temperature measurements.

    PubMed

    Flanagan, Ted B; Wang, Da; Luo, S

    2007-09-13

    In this research, the thermodynamics of H2 solution and hydride formation in a series of disordered Pd-Ag alloys has been determined using both reaction calorimetry and equilibrium PH2-composition-T data. Trends of DeltaHH and DeltaSH with both H and Ag concentration have been determined. For the Pd0.76Ag0.24 alloy, which does not form a hydride phase, DeltaHH and DeltaSH both exhibit minima with H/(Pd0.76Ag0.24) followed by a linear increase of the former. A linear increase of DeltaHH is found for all of the alloys in the high H content region beyond the two-phase region or, if, there is no two-phase region, in the high H content region. DeltaHH degrees at infinite dilution of H decreases with atom fraction Ag, XAg, up to about 0.40 and then increases. Enthalpies for hydride formation/decomposition, 1/2H2(g) + dilute <--> hydride, have been determined calorimetrically for alloys which form two phases (303 K). The enthalpies for hydride formation become more exothermic with XAg while the corresponding entropy magnitudes are nearly constant, 46 +/- 2 J/K mol H. PMID:17711332

  1. Calorimetric and thermomechanical properties of titanium-based orthodontic wires: DSC-DMA relationship to predict the elastic modulus.

    PubMed

    Laino, Giuliana; De Santis, Roberto; Gloria, Antonio; Russo, Teresa; Quintanilla, David Suárez; Laino, Alberto; Martina, Roberto; Nicolais, Luigi; Ambrosio, Luigi

    2012-03-01

    Orthodontic treatment is strongly dependent on the loads developed by metal wires, and the choice of an orthodontic archwire should be based on its mechanical performance. The desire of both orthodontists and engineers would be to predict the mechanical behavior of archwires. To this aim, Gum Metal (Toyota Central R&L Labs., Inc.), TMA (ORMCO), 35°C Copper NiTi (SDS ORMCO), Thermalloy Plus (Rocky Mountain), Nitinol SE (3M Unitek), and NiTi (SDS ORMCO) were tested according to dynamic mechanical analysis and differential scanning calorimetry. A model was also developed to predict the elastic modulus of superelastic wires. Results from experimental tests have highlighted that superelastic wires are very sensitive to temperature variations occurring in the oral environment, while the proposed model seems to be reliable to predict the Young's modulus allowing to correlate calorimetric and mechanical data. Furthermore, Gum Metal wire behaves as an elastic material with a very low Young's modulus, and it can be particularly useful for the initial stage of orthodontic treatments. PMID:21343211

  2. Calorimetric determination of the enthalpy change for the alpha-helix to coil transition of an alanine peptide in water.

    PubMed Central

    Scholtz, J M; Marqusee, S; Baldwin, R L; York, E J; Stewart, J M; Santoro, M; Bolen, D W

    1991-01-01

    The enthalpy change (delta H) accompanying the alpha-helix to random coil transition in water has been determined calorimetrically for a 50-residue peptide of defined sequence that contains primarily alanine. The enthalpy of helix formation is one of the basic parameters needed to predict thermal unfolding curves for peptide helices and it provides a starting point for analysis of the peptide hydrogen bond. The experimental uncertainty in delta H reflects the fact that the transition curve is too broad to measure in its entirety, which precludes fitting the baselines directly. A lower limit for delta H of unfolding, 0.9 kcal/mol per residue, is given by assuming that the change in heat capacity (delta Cp) is zero, and allowing the baseline to intersect the transition curve at the lowest measured Cp value. Use of the van't Hoff equation plus least-squares fitting to determine a more probable baseline gives delta H = 1.3 kcal/mol per residue. Earlier studies of poly(L-lysine) and poly(L-glutamate) have given 1.1 kcal/mol per residue. Those investigations, along with our present result, suggest that the side chain has little effect on delta H. The possibility that the peptide hydrogen bond shows a correspondingly large delta H, and the implications for protein stability, are discussed. PMID:2011594

  3. Calorimetric Low-Temperature Detectors for X-Ray Spectroscopy on Trapped Highly-Charged Heavy Ions

    NASA Technical Reports Server (NTRS)

    Kilbourne, Caroline; Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Ilieva, S.; Kilbourne, C.; McCammon, D.

    2012-01-01

    The application of Calorimetric Low-Temperature Detectors (CLTDs) has been proposed at the Heavy-Ion TRAP facility HITRAP which is currently being installed at the Helmholtz Research Center for Heavy Ion Research GSI. This cold ion trap setup will allow the investigation of X-rays from ions practically at rest, for which the excellent energy resolution of CLTDs can be used to its full advantage. However, the relatively low intensities at HITRAP demand larger solid angles and an optimized cryogenic setup. The influence of external magnetic fields has to be taken into account. CLTDs will also be a substantial part of the instrumental equipment at the future Facility for Antiproton and Heavy Ion Research (FAIR), for which a wide variety of high-precision X-ray spectroscopy experiments has been proposed. This contribution will give an overview on the chances and challenges for the application of CLTDs at HITRAP as well as perspectives for future experiments at the FAIR facility.

  4. Determination of Nuclear Charge Distributions of Fission Fragments from ^{235} U (n_th , f) with Calorimetric Low Temperature Detectors

    NASA Astrophysics Data System (ADS)

    Grabitz, P.; Andrianov, V.; Bishop, S.; Blanc, A.; Dubey, S.; Echler, A.; Egelhof, P.; Faust, H.; Gönnenwein, F.; Gomez-Guzman, J. M.; Köster, U.; Kraft-Bermuth, S.; Mutterer, M.; Scholz, P.; Stolte, S.

    2016-03-01

    Calorimetric low temperature detectors (CLTD's) for heavy-ion detection have been combined with the LOHENGRIN recoil separator at the ILL Grenoble for the determination of nuclear charge distributions of fission fragments produced by thermal neutron-induced fission of ^{235} U. The LOHENGRIN spectrometer separates fission fragments according to their mass-to-ionic-charge ratio and their kinetic energy, but has no selectivity with respect to nuclear charges Z. For the separation of the nuclear charges, one can exploit the nuclear charge-dependent energy loss of the fragments passing through an energy degrader foil (absorber method). This separation requires detector systems with high energy resolution and negligible pulse height defect, as well as degrader foils which are optimized with respect to thickness, homogeneity, and energy loss straggling. In the present, contribution results of test measurements at the Maier Leibnitz tandem accelerator facility in Munich with ^{109} Ag and ^{127} I beams with the aim to determine the most suitable degrader material, as well as measurements at the Institut Laue-Langevin will be presented. These include a systematic study of the quality of Z-separation of fission fragments in the mass range 82≤ A ≤ 132 and a systematic measurement of ^{92} Rb fission yields, as well as investigations of fission yields toward the symmetry region.

  5. Thermogravimetric, Calorimetric, and Structural Studies of the Co3 O4 /CoO Oxidation/Reduction Reaction

    NASA Astrophysics Data System (ADS)

    Unruh, Karl; Cichocki, Ronald; Kelly, Brian; Poirier, Gerald

    2015-03-01

    To better assess the potential of cobalt oxide for thermal energy storage (TES), the Co3O4/CoO oxidation/reduction reaction has been studied by thermogravimetric (TGA), calorimetric (DSC), and x-ray diffraction (XRD) measurements in N2 and atmospheric air environments. TGA measurements showed an abrupt mass loss of about 6.6% in both N2 and air, consistent with the stoichiometric reduction of Co3O4 to CoO and structural measurements. The onset temperature of the reduction of Co3O4 in air was only weakly dependent on the sample heating rate and occurred at about 910 C. The onset temperature for the oxidation of CoO varied between about 850 and 875 C for cooling rates between 1 and 20 C/min, but complete re-conversion to Co3O4 could only be achieved at the slowest cooling rates. Due to the dependence of the rate constant on the oxygen partial pressure, the oxidation of Co3O4 in a N2 environment occurred at temperatures between about 775 and 825 C for heating rates between 1 and 20 C/min and no subsequent re-oxidation of the reduced Co3O4 was observed on cooling to room temperature. In conjunction with a measured transition heat of about 600 J/g of Co3O4, these measurements indicate that cobalt oxide is a viable TES material.

  6. pH-tuneable binding of 2′-phospho-ADP-ribose to ketopantoate reductase: a structural and calorimetric study

    SciTech Connect

    Ciulli, Alessio; Lobley, Carina M. C.; Tuck, Kellie L.; Smith, Alison G.; Blundell, Tom L.; Abell, Chris

    2007-02-01

    A combined crystallographic, calorimetric and mutagenic study has been used to show how changes in pH give rise to two distinct binding modes of 2′-phospho-ADP-ribose to ketopantoate reductase. The crystal structure of Escherichia coli ketopantoate reductase in complex with 2′-monophosphoadenosine 5′-diphosphoribose, a fragment of NADP{sup +} that lacks the nicotinamide ring, is reported. The ligand is bound at the enzyme active site in the opposite orientation to that observed for NADP{sup +}, with the adenine ring occupying the lipophilic nicotinamide pocket. Isothermal titration calorimetry with R31A and N98A mutants of the enzyme is used to show that the unusual ‘reversed binding mode’ observed in the crystal is triggered by changes in the protonation of binding groups at low pH. This research has important implications for fragment-based approaches to drug design, namely that the crystallization conditions and the chemical modification of ligands can have unexpected effects on the binding modes.

  7. Bismaleimide compounds

    DOEpatents

    Adams, J.E.; Jamieson, D.R.

    1986-01-14

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

  8. Bismaleimide compounds

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1986-01-14

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

  9. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

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

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

    PubMed

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

    2015-01-01

    Bi-layer (Au-Si₃N₄) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

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

    PubMed Central

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

    2015-01-01

    Bi-layer (Au-Si3N4) microcantilevers fabricated in an array were used to detect vapors of energetic materials such as explosives under ambient conditions. The changes in the bending response of each thermal bimorph (i.e., microcantilever) with changes in actuation currents were experimentally monitored by measuring the angle of the reflected ray from a laser source used to illuminate the gold nanocoating on the surface of silicon nitride microcantilevers in the absence and presence of a designated combustible species. Experiments were performed to determine the signature response of this nano-calorimeter platform for each explosive material considered for this study. Numerical modeling was performed to predict the bending response of the microcantilevers for various explosive materials, species concentrations, and actuation currents. The experimental validation of the numerical predictions demonstrated that in the presence of different explosive or combustible materials, the microcantilevers exhibited unique trends in their bending responses with increasing values of the actuation current. PMID:26334276

  12. Thermochemistry of alkyl pyridinium bromide ionic liquids: calorimetric measurements and calculations.

    PubMed

    Tong, Bo; Liu, Qing-Shan; Tan, Zhi-Cheng; Welz-Biermann, Urs

    2010-03-25

    Two ionic liquids, 1-ethylpyridinium bromide (EPBr) and 1-propylpyridinium bromide (PPBr), were prepared and the structures were characterized by 1H NMR. The thermodynamic properties of EPBr and PPBr were studied with adiabatic calorimetry (AC) and thermogravimatric analysis (TG-DTG). The heat capacity was precisely measured in the temperature range from 78 to 410 K by means of a fully automated adiabatic calorimeter. For EPBr, the melting temperature, enthalpy, and entropy of solid-liquid phase transition were determined to be 391.31 +/- 0.28 K, 12.77 +/- 0.09 kJ x mol(-1), and 32.63 +/- 0.22 J x K(-1) x mol(-1), respectively, and for PPBr they were 342.83 +/- 0.69 K, 10.97 +/- 0.05 kJ x mol(-1), and 32.00 +/- 0.10 J x K(-1) x mol(-1), respectively. The thermodynamic functions (H(T)(0) - H(298.15)(0)) and (S(T)(0) - S(298.15)(0)) were derived from the heat capacity data in the experimental temperature range with an interval of 5 K. The thermostablility of the compounds was further studied by TGA measurements. The phase change behavior and thermodynamic properties were compared and estimated in a series of alkyl pyridinium bromide ionic liquids. Results indicate that EPBr has higher melting and decomposition temperature, as well as phase transition enthalpy and entropy but lower heat capacity than PPBr due to their different molecular structures. PMID:20235601

  13. Calorimetric and spectroscopic studies on solvation energetics for H2 storage in the CO2/HCOOH system.

    PubMed

    Fink, Cornel; Katsyuba, Sergey; Laurenczy, Gabor

    2016-04-20

    Solvents playing a crucial role in many chemical reactions and additives can be used to shift the reaction equilibrium. Herein we study the enthalpy of mixing for selected solvents (aqueous, organic) and basic additives (amines, aqueous KOH) when mixed with formic acid with the aim to optimize hydrogen storage/delivery in the CO2/HCOOH system. Formic acid, resulting from carbon dioxide hydrogenation, reaches highest yields when effectively "removed" from the reaction equilibrium. In terms of energy efficiency, any heat released during CO2 hydrogenation has to be reused in the reverse reaction, during the production of hydrogen. In any scenario, the usage of basic chemicals, non-innocent solvents, causes higher energy release in CO2 hydrogenation, which has to be reused in the hydrogen delivery process. Therefore, the enthalpy of mixing is a valuable parameter for designing hydrogen storage devices since it allows the estimation of energy balance for the CO2 hydrogenation/H2 liberation cycle. The highest formic acid concentrations in direct catalytic CO2 hydrogenation under acidic conditions were reached in DMSO. DMSO exhibits considerably stronger interactions with formic acid compared to water as was observed in calorimetric measurements. This difference can be ascribed, at least partly, to stronger hydrogen bonding of FA to DMSO than to water in the corresponding solutions, examined by a combination of IR spectroscopic and quantum chemical studies. Furthermore, the investigation of DMSO/FA- and water/FA systems by (1)H- and (13)C-NMR spectroscopy revealed that only 1 : 1 aggregates are formed in the DMSO solutions of FA in a broad concentration range, while the stoichiometry and the number of the FA-water aggregates essentially depend on the concentration of aqueous solutions. PMID:26890151

  14. Spectroscopic and calorimetric studies on the binding of an indoloquinoline drug to parallel and antiparallel DNA triplexes.

    PubMed

    Riechert-Krause, Fanny; Autenrieth, Karolin; Eick, Andrea; Weisz, Klaus

    2013-01-01

    11-Phenyl-substituted indoloquinolines have been found to exhibit significant antiproliferative potency in cancer cells but to show only moderate affinity toward genomic double-helical DNA. In this study, parallel as well as antiparallel triple-helical DNA targets are employed to evaluate the triplex binding of these ligands. UV melting experiments with parallel triplexes indicate considerable interactions with the drug and a strong preference for TAT-rich triplexes in line with an increasing number of potential intercalation sites of similar binding strength between two TAT base triads. Via substitution of a singly charged aminoethylamine side chain by a longer and doubly charged bis(aminopropyl)amine substituent at the ligand, binding affinities increase and also start to exhibit long-range effects as indicated by a strong correlation between the binding affinity and the overall length of the TAT tract within the triplex stem. Compared to parallel triplexes, an antiparallel triplex with a GT-containing third strand constitutes a preferred target for the indoloquinoline drug. On the basis of pH-dependent titration experiments and corroborated by a Job analysis of continuous variation, binding of the drug to the GT triplex not only is strongly enhanced when the solution pH is lowered from 7 to 5 but also reveals a pH-dependent stoichiometry upon formation of the complex. Calorimetric data demonstrate that stronger binding of a protonated drug at acidic pH is associated with a more exothermic binding process. However, at pH 7 and 5, binding is enthalpically driven with additional favorable entropic contributions. PMID:23234257

  15. Localized Recrystallization in Cast Al-Si-Mg Alloy during Solution Heat Treatment: Dilatometric and Calorimetric Studies

    NASA Astrophysics Data System (ADS)

    Chaudhury, S. K.; Warke, V.; Shankar, S.; Apelian, D.

    2011-10-01

    During heat treatment, the work piece experiences a range of heating rates depending upon the sizes and types of furnace. When the Al-Si-Mg cast alloy is heated to the solutionizing temperature, recrystallization takes place during the ramp-up stage. The effect of heating rate on recrystallization in the A356 (Al-Si-Mg) alloy was studied using dilatometric and calorimetric methods. Recrystallization in as-cast Al-Si alloys is a localized event and is confined to the elasto-plastic zone surrounding the eutectic Si phase; there is no evidence of recrystallization in the center of the primary Al dendritic region. The size of the elasto-plastic zone is of the same order of magnitude as the Si particles, and recrystallized grains are observed in the elasto-plastic region near the Si particles. The coefficient of thermal expansion of Al is an order of magnitude greater than Si, and thermal stresses are generated due to the thermal mismatch between the Al phase and Si particles providing the driving force for recrystallization. In contrast, recrystallization in Al wrought alloy (7075) occurs uniformly throughout the matrix, stored energy due to cold work being the driving force for recrystallization in wrought alloys. The activation energy for recrystallization in as-cast A356 alloy is 127 KJ/mole. At a slow heating rate of 4.3 K/min, creep occurs during the heating stage of solution heat treatment. However, creep does not occur in samples heated at higher heating rates, namely, 520, 130, and 17.3 K/min.

  16. Trophic relay and prey switching - A stomach contents and calorimetric investigation of an ambassid fish and their saltmarsh prey

    NASA Astrophysics Data System (ADS)

    McPhee, Jack J.; Platell, Margaret E.; Schreider, Maria J.

    2015-12-01

    Trophic relay is an ecological model that involves the movement of biomass and energy from vegetation, such as saltmarshes, within estuaries to the open sea via a series of predator-prey relationships. Any potential for trophic relay is therefore affected by water movements within an estuary and by the ability of a predator to "switch" prey in response to fluctuating abundances of those prey. Saltmarsh-dwelling grapsid crabs, which feed on saltmarsh-derived detritus and microphytobenthos, release zoeae into ebbing tides that inundate saltmarshes during spring-tide cycles within tidally-dominated estuaries, such as Brisbane Water Estuary, therefore providing an opportunity to examine whether prey-switching and/or trophic relay may occur in fish that feed on those zoeae (such as the highly abundant estuarine ambassid, Ambassis jacksoniensis). This model was examined by sampling A. jacksoniensis near saltmarshes in a large, temperate south-eastern Australian estuary during flood and ebb tides on days of saltmarsh inundation and non-inundation over four spring-tide events in 2012. Stomach fullnesses of A. jacksoniensis were generally highest during ebb tides on days of saltmarsh inundation, implying that feeding was most marked at these times. Caridean decapods dominated diets during flood tides and on days of no saltmarsh inundation, while crab zoeae dominated diets during ebb tides and on days of inundation, suggesting that, when saltmarsh-derived zoeae became abundant, A. jacksoniensis switched to feeding on those prey. Three potential zooplankton prey (calanoid copepods, caridean decapods and crab zoeae) did not differ calorimetrically, indicating that switching of prey by A. jacksoniensis is not directly related to their preying on energetically greater prey, but reflects opportunistic feeding on more abundant and/or less elusive prey. As A. jacksoniensis is able to switch prey from estuarine caridean decapods to saltmarsh-derived crab zoeae, this very abundant ambassid would be well-placed to promote any trophic relay, via further water movements or other predator-prey relationships, to the adjacent marine environment.

  17. Calorimetric and acoustic emission study of martensitic transformation in single-crystalline Ni2MnGa alloys

    NASA Astrophysics Data System (ADS)

    Tóth, László Z.; Szabó, Sándor; Daróczi, Lajos; Beke, Dezső L.

    2014-12-01

    The jerky character of austenite-martensite phase transformation in Ni2MnGa single crystals (with 10M martensite structure) has been investigated by thermal cycling using a differential scanning calorimeter (DSC) and by detection of acoustic emissions (AEs) at low cooling and heating rates (0.1 K/min and below). It is illustrated that, besides the low cooling and heating rate, mass and surface roughness are also important parameters in optimizing the best signal/noise ratio in order to obtain individual peaks suitable for statistical analysis. Three types of samples, differing in the twin structure and twin boundary behavior, were investigated with and without surface roughening made by electro-erosion. The statistical analysis, carried out for both (thermal and acoustic) types of signals, provided power-law behavior. In calorimetric measurements the energy exponents, obtained in cooling, were the same within the experimental errors (ɛ =1.7 ±0.2 ) for the three samples investigated. In acoustic emission experiments the energy and amplitude, α , exponents were determined both for cooling and heating. The exponents for cooling and heating runs are slightly different. They are larger for heating for both α and ɛ , in accordance with the asymmetric acoustic activity: we observed higher acoustic activity (higher number of hits) during cooling. The effect of the surface roughness is negligible in the exponents (but higher acoustic activity corresponds to higher roughness) and the following values were obtained: ɛ =1.5 ±0.1 and α =2.1 ±0.1 for cooling as well as ɛ =1.8 ±0.1 and α =2.6 ±0.1 for heating. Our results are in accordance with the results of Gallardo et al. [Phys. Rev. B 81, 174102 (2010), 10.1103/PhysRevB.81.174102] obtained in Cu based alloys: the exponents of the energy distributions, for both DSC and AE signals, were the same within the experimental errors. Furthermore, our exponents obtained from the AE measurements are close to the values obtained by Ludwig et al. (α =2.6 ±0.1 and ɛ =1.75 ±0.1 ) [App. Phys. Lett. 94 121901 (2009), 10.1063/1.3103289] and Niemann et al. (ɛ =1.9 ±0.1 ) [Phys. Rev. B 86, 214101 (2012), 10.1103/PhysRevB.86.214101] in Ni2MnGa alloys with similar 10M martensite structure.

  18. Micromechanical calorimetric sensor

    DOEpatents

    Thundat, Thomas G.; Doktycz, Mitchel J.

    2000-01-01

    A calorimeter sensor apparatus is developed utilizing microcantilevered spring elements for detecting thermal changes within a sample containing biomolecules which undergo chemical and biochemical reactions. The spring element includes a bimaterial layer of chemicals on a coated region on at least one surface of the microcantilever. The chemicals generate a differential thermal stress across the surface upon reaction of the chemicals with an analyte or biomolecules within the sample due to the heat of chemical reactions in the sample placed on the coated region. The thermal stress across the spring element surface creates mechanical bending of the microcantilever. The spring element has a low thermal mass to allow detection and measuring of heat transfers associated with chemical and biochemical reactions within a sample placed on or near the coated region. A second surface may have a different material, or the second surface and body of microcantilever may be of an inert composition. The differential thermal stress between the surfaces of the microcantilever create bending of the cantilever. Deflections of the cantilever are detected by a variety of detection techniques. The microcantilever may be approximately 1 to 200 .mu.m long, approximately 1 to 50 .mu.m wide, and approximately 0.3 to 3.0 .mu.m thick. A sensitivity for detection of deflections is in the range of 0.01 nanometers. The microcantilever is extremely sensitive to thermal changes in samples as small as 30 microliters.

  19. Calorimetric system and method

    DOEpatents

    Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.; Moorman, Jack O.

    1998-09-15

    Apparatus for measuring heat capacity of a sample where a series of measurements are taken in succession comprises a sample holder in which a sample to be measured is disposed, a temperature sensor and sample heater for providing a heat pulse thermally connected to the sample, and an adiabatic heat shield in which the sample holder is positioned and including an electrical heater. An electrical power supply device provides an electrical power output to the sample heater to generate a heat pulse. The electrical power from a power source to the heat shield heater is adjusted by a control device, if necessary, from one measurement to the next in response to a sample temperature-versus-time change determined before and after a previous heat pulse to provide a subsequent sample temperature-versus-time change that is substantially linear before and after the subsequent heat pulse. A temperature sensor is used and operable over a range of temperatures ranging from approximately 3K to 350K depending upon the refrigerant used. The sample optionally can be subjected to dc magnetic fields such as from 0 to 12 Tesla (0 to 120 kOe).

  20. Calorimetric system and method

    DOEpatents

    Gschneidner, K.A. Jr.; Pecharsky, V.K.; Moorman, J.O.

    1998-09-15

    Apparatus is described for measuring heat capacity of a sample where a series of measurements are taken in succession comprises a sample holder in which a sample to be measured is disposed, a temperature sensor and sample heater for providing a heat pulse thermally connected to the sample, and an adiabatic heat shield in which the sample holder is positioned and including an electrical heater. An electrical power supply device provides an electrical power output to the sample heater to generate a heat pulse. The electrical power from a power source to the heat shield heater is adjusted by a control device, if necessary, from one measurement to the next in response to a sample temperature-versus-time change determined before and after a previous heat pulse to provide a subsequent sample temperature-versus-time change that is substantially linear before and after the subsequent heat pulse. A temperature sensor is used and operable over a range of temperatures ranging from approximately 3K to 350K depending upon the refrigerant used. The sample optionally can be subjected to dc magnetic fields such as from 0 to 12 Tesla (0 to 120 kOe). 18 figs.

  1. Electrical properties and conduction mechanism of [C2H5NH3]2CuCl4 compound

    NASA Astrophysics Data System (ADS)

    Mohamed, C. Ben; Karoui, K.; Jomni, F.; Guidara, K.; Rhaiem, A. Ben

    2015-02-01

    The [(C2H5)NH3]2CuCl4 compound was prepared and characterized by several technique: the X-ray powder diffraction confirms the purity of the synthetized compound, the differential scanning calorimetric show several phase transitions at 236 K, 330 K, 357 K and 371 K, the dialectical properties confirms the ferroelectric-paraelectric phase transition at 238 K, which is reported by V. Kapustianyk et al. (2007) [1]. The two semi-circles observed in the complex impedance identify the presence of the grain interior and grain boundary contributions to the electrical response in this material. The equivalent circuit is modeled by a combination series of two parallel RP-CPE circuits. The temperature dependence of the alternative current conductivity (σg) and direct current conductivity (σdc) confirm the observed transitions in the calorimetric study. The (AC) electrical conduction in [(C2H5)NH3]2CuCl4 was studied by two processes that can be attributed to a hopping transport mechanism: the non-overlapping small polaron tunneling (NSPT) model in phase III and the correlated barrier hopping (CBH) model in phases I, II, IV, V and VI.

  2. Calorimetric, X-Ray Diffraction, and Spectroscopic Studies of the Thermotropic Phase Behavior and Organization of Tetramyristoyl Cardiolipin Membranes

    PubMed Central

    Lewis, Ruthven N. A. H.; Zweytick, Dagmar; Pabst, Georg; Lohner, Karl; McElhaney, Ronald N.

    2007-01-01

    The thermotropic phase behavior and organization of aqueous dispersions of the quadruple-chained, anionic phospholipid tetramyristoyl diphosphatidylglycerol or tetramyristoyl cardiolipin (TMCL) was studied by differential scanning calorimetry, x-ray diffraction, 31P NMR, and Fourier-transform infrared (FTIR) spectroscopy. At physiological pH and ionic strength, our calorimetric studies indicate that fully equilibrated aqueous dispersions of TMCL exhibit two thermotropic phase transitions upon heating. The lower temperature transition is much less cooperative but of relatively high enthalpy and exhibits marked cooling hysteresis, whereas the higher temperature transition is much more cooperative and also exhibits a relatively high enthalpy but with no appreciable cooling hysteresis. Also, the properties of these two-phase transitions are sensitive to the ionic strength of the dispersing buffer. Our spectroscopic and x-ray diffraction data indicate that the lower temperature transition corresponds to a lamellar subgel (Lc?) to gel (L?) phase transition and the higher temperature endotherm to a L? to lamellar liquid-crystalline (L?) phase transition. At the Lc?/L? phase transition, there is a fivefold increase of the thickness of the interlamellar aqueous space from ?11 to ?50 , and this value decreases slightly at the L?/L? phase transition. The bilayer thickness (i.e., the mean phosphate-phosphate distance across the bilayer) increases from 42.8 to 43.5 at the Lc?/L? phase transition, consistent with the loss of the hydrocarbon chain tilt of ?12, and decreases to 37.8 at the L?/L? phase transition. The calculated cross-sectional areas of the TMCL molecules are ?79 2 and ?83 2 in the Lc? and L? phases, respectively, and we estimate a value of ?100 2 in the L? phase. The combination of x-ray and FTIR spectroscopic data indicate that in the Lc? phase, TMCL molecules possess tilted all-trans hydrocarbon chains packed into an orthorhombic subcell in which the zig-zag planes of the chains are parallel, while in the L? phase the untilted, all-trans hydrocarbon chains possess rotational mobility and are packed into a hexagonal subcell, as are the conformationally disordered hydrocarbon chains in the L? phase. Our FTIR spectroscopic results demonstrate that the four carbonyl groups of the TMCL molecule become progressively more hydrated as one proceeds from the Lc? to the L? and then to the L? phase, while the two phosphate moieties of the polar headgroup are comparably well hydrated in all three phases. Our 31P-NMR results indicate that although the polar headgroup retains some mobility in the Lc? phase, its motion is much more restricted in the L? and especially in the L? phase than that of other phospholipids. We can explain most of our experimental results on the basis of the relatively small size of the polar headgroup of TMCL relative to other phospholipids and the covalent attachment of the two phosphate moieties to a single glycerol moiety, which results in a partially immobilized polar headgroup that is more exposed to the solvent than in other glycerophospholipids. Finally, we discuss the biological relevance of the unique properties of TMCL to the structure and function of cardiolipin-containing biological membranes. PMID:17293402

  3. Calorimetric Study of Phase Stability and Phase Transformation in U- xZr ( x = 2, 5, 10 wt pct) Alloys

    NASA Astrophysics Data System (ADS)

    Rai, Arun Kumar; Subramanian, Raju; Hajra, Raj Narayan; Tripathy, Haraprasanna; Rengachari, Mythili; Saibaba, Saroja

    2015-11-01

    A comprehensive calorimetric study of high-temperature phase equilibria and phase transformation characteristics in U- xZr ( x = 2, 5, 10 wt pct) alloys has been undertaken, as a function of heating and cooling rates. It is found that the following sequence of phase transformation takes place upon slow heating in annealed U-2 wt pct Zr alloy: α + α' + δ-UZr2 → α + γ 2 → β + γ 2 → β + γ 1 → γ. For alloys of 5 and 10 wt pct Zr, the additional presence of a miscibility gap ( γ 1 U-rich bcc + γ 2 Zr-rich bcc) in the high-temperature γ(bcc) phase region resulted in the following transformation sequence: α + α' + δ-UZr2 → α + γ 2 → β + γ 2 → γ 1 + γ 2 → γ. Further, it has been demonstrated that depending on the nature of starting microstructure, namely whether it is α eq + δ-UZr2, or a mix of α' + α eq + δ-UZr2 phases, the relative extents of two possible co-occurring modes of the first on-heating phase transformation step differ. In case of starting microstructure having mixture of three phases α' + α eq + δ-UZr2, it is found that α'-martensite relaxation via α' + α eq + δ-UZr2 → α eq + δ-UZr2 constitutes the first on-heating thermal response. The α'-martensitic relaxation is very closely followed by the dissolution of δ-UZr2. The co-occurrence of these two events gives rise to a composite thermal arrest in a normal dynamic calorimetry profile. However, if the starting microstructure is the one having the equilibrium mix of α eq and δ-UZr2, then only the peritectoidal dissolution of δ-UZr2 is found in the calorimetry profile. Unless, a very slow cooling rate of the order of 0.1 K min-1 is adopted from high-temperature γ(bcc) phase, it is not possible to obtain 100 pct of α eq phase along with equilibrium amount of δ-UZr2. At normal and high cooling rates, it is possible to suppress the diffusional decomposition of γ to varying extents. The direct γ → α'-martensite transformation has been observed at sufficiently higher cooling rates. It has been also noticed that even after γ → α'-martensite transformation the precipitation of δ-UZr2 phase is possible at lower temperature during non-isothermal cooling. Further, the critical cooling rate required for γ → α' displacive transformation is found to decrease with increasing Zr content. For U-2, 5, and 10 wt pct Zr alloys, it is found to be of the order of, 60, 20, 10 K min-1, respectively. The cooling rate from high-temperature γ(bcc) is found have a strong influence on microstructure evolution as well. The kinetic aspects of α → β diffusional transformation that occurs on heating have been modeled in terms of Kolmogorov-Johnson-Mehl-Avrami formalism, and it is found that the transformation is effectively controlled by the diffusion of Zr in α'-orthorhombic phase. Continuous heating and cooling transformation diagrams have also been obtained for U-2 wt pct Zr alloy.

  4. The Bayer Facts of Science Education XVI: US STEM Workforce Shortage— Myth or Reality? Fortune 1000 Talent Recruiters on the Debate

    NASA Astrophysics Data System (ADS)

    Bayer Corporation

    2014-10-01

    A major debate is currently underway in the USA about whether there is, in fact, a science, technology, engineering and mathematics (STEM) workforce shortage in the country or not. This is the subject of the Bayer Facts of Science Education XVI: US STEM Workforce Shortage—Myth or Reality? Fortune 1000 Talent Recruiters on the Debate. An ongoing public opinion research project commissioned by Bayer Corporation, the Bayer Facts surveys examine US STEM education, diversity and workforce issues. The 16th in the series, the newest survey asks talent recruiters at some of the country's largest employers—those included in the Fortune 1000—to weigh in on current and future demand for new hires with 2- and 4-year STEM degrees. As professionals responsible for scouting, recruiting and hiring talent at Fortune 1000 companies, both STEM and non-STEM alike, these individuals are on the frontlines, tasked with assessing and filling their companies' workforce needs. The survey asks the recruiters whether new hires with 2- and 4-year STEM degrees are as, more or less in demand than their peers without STEM degrees? Are more new STEM jobs being created at their companies than non-STEM jobs? Can they find adequate numbers of qualified candidates in a timely manner and how fierce is the competition for STEM degree holders? To answer these and other questions, the survey polled 150 talent recruiters at Fortune 1000 companies, both STEM and non-STEM alike. The survey also asks the recruiters about diversion in STEM, workforce diversity in the pipeline, the role of community colleges in developing the STEM pipeline and the desired skills and competencies of new hires.

  5. Combinatorial materials research applied to the development of new surface coatings XVI: fouling-release properties of amphiphilic polysiloxane coatings.

    PubMed

    Stafslien, Shane J; Christianson, David; Daniels, Justin; VanderWal, Lyndsi; Chernykh, Andrey; Chisholm, Bret J

    2015-01-01

    High-throughput methods were used to prepare and characterize the fouling-release (FR) properties of an array of amphiphilic polysiloxane-based coatings possessing systematic variations in composition. The coatings were derived from a silanol-terminated polydimethylsiloxane, a silanol-terminated polytrifluorpropylmethylsiloxane (CF3-PDMS), 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane (TMS-PEG), methyltriacetoxysilane and hexamethyldisilazane-treated fumed silica. The variables investigated were the concentration of TMS-PEG and the concentration of CF3-PDMS. In general, it was found that the TMS-PEG and the CF3-PDMS had a synergist effect on FR properties with these properties being enhanced by combining both compounds into the coating formulations. In addition, reattached adult barnacles removed from coatings possessing both TMS-PEG and relatively high levels of CF3-PDMS displayed atypical base-plate morphologies. The majority of the barnacles removed from these coatings exhibited a cupped or domed base-plate as compared to the flat base-plate observed for the control coating that did not contain TMS-PEG or CF3-PDMS. Coating surface analysis using water contact angle measurements indicated that the presence of CF3-PDMS facilitated migration of TMS-PEG to the coating/air interface during the film formation/curing process. In general, coatings containing both TMS-PEG and relatively high levels of CF3-PDMS possessed excellent FR properties. PMID:25647177

  6. Spectroscopic and calorimetric studies of formation of the supramolecular complexes of PAMAM G5-NH₂ and G5-OH dendrimers with 5-fluorouracil in aqueous solution.

    PubMed

    Buczkowski, Adam; Olesinski, Tomasz; Zbicinska, Elzbieta; Urbaniak, Pawel; Palecz, Bartlomiej

    2015-07-25

    The results of spectroscopic measurements (increase in solubility, equilibrium dialysis, (1)H NMR titration) and calorimetric measurements (isothermal titration ITC) indicate exothermic (ΔH<0) and spontaneous (ΔG < 0) combination of an antitumor drug, 5-fluorouracil, by both cationic PAMAM G5-NH2 dendrimer and its hydroxyl analog PAMAM G5-OH in aqueous solutions at room temperature. PAMAM G5-NH2 dendrimer combines about 70 molecules of the drug with equilibrium constant K ≅ 300, which is accompanied by an increase in the system order (ΔS < 0). Hydroxyl dendrimer, PAMAM G5-OH, combines about 14 molecules of 5-fluorouracil with equilibrium constant K ≅ 100. This process is accompanied by an increase in the system disorder (ΔS > 0). PMID:25997661

  7. Search for Low-Mass Weakly Interacting Massive Particles Using Voltage-Assisted Calorimetric Ionization Detection in the SuperCDMS Experiment

    NASA Astrophysics Data System (ADS)

    Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.; Brandt, D.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Cerdeno, D. G.; Chagani, H.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hertel, S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Loer, B.; Lopez Asamar, E.; Mahapatra, R.; Mandic, V.; Martinez, C.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Moore, D. C.; Nadeau, P.; Nelson, R. H.; Page, K.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Villano, A. N.; Welliver, B.; Wright, D. H.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.; SuperCDMS Collaboration

    2014-01-01

    SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV /c2.

  8. Calorimetric Studies of the Energetics of Order-Disorder in the System Mg(1-x)Fe(x)Ca(CO(3))(2)

    SciTech Connect

    Brady, P.; Dooley, D.; Navrotsky, A.; Reeder, R.

    1999-02-10

    Calorimetric studies by Chai and Navrotsky (1996) on dolomite-ankerite energetic have been extended by including two additional types of samples: a very disordered stoichiometric MgCa(CO{sub 3}){sub 2} prepared from low temperature aqueous solution and three largely ordered natural samples of intermediate iron content. Combining these data with previous work, three distinct trends of energetic can be seen: those for samples with nearly complete order, nearly complete disorder, and intermediate order. From these trends, the enthalpy of complete disordering is estimated to be 33 {+-} 6 kJ/mol for MgCa(CO{sub 3}){sub 2} and 18 {+-} 5 kJ/mol for FeCa(CO{sub 3}){sub 2}.

  9. Calorimetric determination of the magnetic phase diagram of underdoped ortho II YBa2Cu3O6.54 single crystals

    PubMed Central

    Marcenat, C.; Demuer, A.; Beauvois, K.; Michon, B.; Grockowiak, A.; Liang, R.; Hardy, W.; Bonn, D. A.; Klein, T.

    2015-01-01

    The recent discovery of a charge order in underdoped YBa2Cu3Oy raised the question of the interplay between superconductivity and this competing phase. Understanding the normal state of high-temperature superconductors is now an essential step towards the description of the pairing mechanism in those materials and determining the upper critical field is therefore of fundamental importance. We present here a calorimetric determination of the field–temperature phase diagram in underdoped YBa2Cu3Oy single crystals. We show that the specific heat saturates in high magnetic fields. This saturation is consistent with a normal state without any significant superconducting contribution and a total Sommerfeld coefficient γN∼6.5±1.5 mJ mol−1 K−2 putting strong constraints on the theoretical models for the Fermi surface reconstruction. PMID:26294047

  10. Thermodynamic properties of illite, smectite and beidellite by calorimetric methods: Enthalpies of formation, heat capacities, entropies and Gibbs free energies of formation

    NASA Astrophysics Data System (ADS)

    Gailhanou, H.; Blanc, P.; Rogez, J.; Mikaelian, G.; Kawaji, H.; Olives, J.; Amouric, M.; Denoyel, R.; Bourrelly, S.; Montouillout, V.; Vieillard, P.; Fialips, C. I.; Michau, N.; Gaucher, E. C.

    2012-07-01

    The thermodynamic properties of three aluminous 2:1 clay minerals were acquired at 1.013 bars and at temperatures between 5 and 500 K using various calorimetric methods. Calorimetric measurements were performed on hydrated and dehydrated <2 μm clay fractions of smectite MX-80 (Wyoming), illite IMt-2 (Silver Hill) and beidellite SBId-1 (Black Jack Mine). After purification, the mineralogical analyses gave the following structural formulae: Na0.409K0.024Ca0.009 (Si3.738Al0.262) (Al1.598Mg0.214Fe 0.173 3 + Fe 0.035 2 +)O10(OH)2,K0.762Na0.044 (Si3.387Al0.613) (Al1.427Mg0.241Fe 0.292 3 + Fe 0.084 2 +)O10(OH)2 and Ca0.185K0.104 (Si3.574Al0.426) (Al1.812Mg0.09Fe 0.112 3 +)O10(OH)2 for smectite MX-80, illite IMt-2 and beidellite SBId-1, respectively. Heat capacities were measured by low temperature adiabatic calorimetry and differential scanning calorimetry, from 5 to 500 K. Standard enthalpies of formation were obtained from solution-reaction calorimetry at 298.15 K. The standard Gibbs free energies of formation of the clay minerals were also calculated, together with the equilibrium constants at 25 °C, for anhydrous and hydrated minerals. A comparison between these experimental data and estimated values obtained from prediction models available in the literature, enabled the calculation method that appears to be the most relevant to be selected, at least for aluminous 2:1 clay minerals.

  11. Coproportionation thermodynamics of homoligand solvates of samarium(III) and Yttrium(III) nitrates with neutral organophosphorus compounds

    SciTech Connect

    Pyartman, A.K.

    1995-07-01

    The heats of coproportionation of homoligand solvates of samarium(III) and yttrium(III) nitrates with neutral organophosphorus compounds (tri-n-butyl phosphate, diisooctyl methylphosphonate, and diisoamyl methylphosphonate) in hexane at 298.15 K have been determined calorimetrically. The enthalpies of coproportionation are virtually independent of the nature and concentration of solvates of rare earth metal(III) nitrates in hexane and of the nature of neutral organophosphorus compound and amount to -1.1{plus_minus}0.2 kJ mol{sup -1}. The Gibbs free energy of coproportionation is -5.43 kJ mol{sup -1}, and the entropy is 14.5{plus_minus}0.7 J mol{sup -1} K{sup -1}.

  12. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  13. Caulking compound poisoning

    MedlinePlus

    Caulking compounds are substances used to seal cracks and holes around windows and other openings. Caulking compound poisoning occurs when someone swallows these substances. This is for information only and not for use in the ...

  14. Regulating compounding pharmacies.

    PubMed

    Noble, Ashley

    2015-06-01

    (1) The Pew Charitable Trusts identified 27 compounding incidents that resulted in 89 deaths since 2001. (2) Unlike drug manufacturers, compounding pharmacies are generally not required to report adverse events associated with their products to the FDA. (3) Federal law on drug compounding was updated in 2013 to create a new group of compounders called "outsourcing facilities." Over 50 facilities in 23 states are now registered with the FDA. PMID:26137607

  15. Identification of polyphenolic compounds in the flesh of Argan (Morocco) fruits.

    PubMed

    Khallouki, Farid; Haubner, Roswitha; Ricarte, Irvila; Erben, Gerhard; Klika, Karel; Ulrich, Cornelia M; Owen, Robert W

    2015-07-15

    High performance liquid chromatography coupled with negative electrospray ionization (HPLC-ESI) along with fragmentation patterns generated by nano-electrospray ionization (nano-ESI-MS-MS) and NMR techniques were utilized for the identification of phenolic compounds in Argan fruits. A total of 15.4 g/kg was determined represented by catechins (39%), flavonoids (28%), procyanidins (26%), free phenolic acids (6%) and phenolic acid glycosides (1%). Twenty-one phenolic compounds were identified for the first time in Argan fruits namely III. epicatechin-(4β→8)-catechin dimer (procyanidin B1), IV. p-coumaric acid glycoside, VI. epicatechin-(4β→8)-epicatechin dimer (procyanidin B2), VIII. caffeic acid glycoside, XIX. epicatechin-(4β→8)-epicatechin-(4β→8)-epicatechin trimer (procyanidin C1), X. p-hydroxybenzaldehyde XI. ferulic acid glycoside, XII. vanillic acid, XIII. sinapic acid glycoside, XVI. p-coumaric acid, XVII. ferulic acid, XVIII. sinapic acid, XIX. rutin pentoside, XX. quercetin glycopentoside, XXI. 4,4'-dihydroxy-3,3'-imino-di-benzoic acid, XXV. quercetin-3-O-rhamnogalactoside, XXVII. quercetin glycohydroxybenzoate, XXVIII. quercetin glycocaffeate, XXIX. quercetin glycosinapate, XXX. quercetin glycoferulate and XXXI. quercetin glycocoumarate. PMID:25722154

  16. To study the RF properties of superconducting A15 compounds

    NASA Astrophysics Data System (ADS)

    Beasley, M. R.; Geballe, T. H.; Schwettman, H. A.

    1981-07-01

    The purpose of the work was to study the low RF-field loss of A15 superconducting compounds. This type of superconducting material has potential for application to the construction of microwave energy storage cavities whose energy can be dumped in a very short time so as to produce a very large microwave power pulse. An apparatus, using a calorimetric technique, was developed to measure the surface resistance of small-area superconducting samples deposited on sapphire substrates. Both a Nb and a Nb3Sn sample (the latter in the A15 structure) were prepared, characterized and measured. These initial measurements revealed additional losses that are most likely due to the region near the superconductor-sapphire interface. Measurements of the superconducting transition temperature were made as a function of film thickness to study the effect of the interface. The interface losses can be avoided in practice, and in our measurements they can be circumvented by employing a circularly cylindrical geometry which shields the interface region from the rf fields. In the course of developing the surface resistance apparatus, dielectric loss measurements were made on pure sapphire samples.

  17. Effects of methoxy and formyl substituents on the energetics and reactivity of α-naphthalenes: a calorimetric and computational study.

    PubMed

    Silva, Ana L R; Freitas, Vera L S; Ribeiro da Silva, Maria D M C

    2014-07-01

    A combined experimental and computational study was developed to evaluate and understand the energetics and reactivity of formyl and methoxy α-naphthalene derivatives. Static bomb combustion calorimetry and the Calvet microcalorimetry were the experimental techniques used to determine the standard (p(o)=0.1 MPa) molar enthalpies of formation, in the liquid phase, ΔfHm(o)(l), and of vaporization, Δl(g)Hm(o), at T=298.15K, respectively, of the two liquid naphthalene derivatives. Those experimental values were used to derive the values of the experimental standard molar enthalpies of formation, in the gaseous phase, ΔfHm(o)(g), of 1-methoxynaphthalene, (-3.0 ± 3.1)kJmol(-1), and of 1-formylnaphthalene, (36.3 ± 4.1)kJ mol(-1). High-level quantum chemical calculations at the composite G3(MP2)//B3LYP level were performed to estimate the values of the ΔfHm(o)(g) of the two compounds studied resulting in values in very good agreement with experimental ones. Natural bond orbital (NBO) calculations were also performed to determine more about the structure and reactivity of this class of compounds. PMID:24444416

  18. A calorimetric study of the folding-unfolding of an alpha-helix with covalently closed N and C-terminal loops.

    PubMed

    Taylor, J W; Greenfield, N J; Wu, B; Privalov, P L

    1999-08-27

    The thermal melting of a dicyclic 29-residue peptide, having helix-stabilizing side-chain to side-chain covalent links at each terminal, has been studied by circular dichroism spectropolarimetry (CD) and differential scanning calorimetry (DSC). The CD spectra for this dicyclic peptide indicate that it is monomeric, almost fully alpha-helical at -10 degrees C, and undergoes a reversible transition from the folded to the disordered state with increasing temperature. The temperature dependencies of the ellipticity at 222 nm and the excess heat capacity measured calorimetrically are well fit by a two-state model, which indicates a cooperative melting transition that is complete within the temperature ranges of these experiments (from -10 degrees C to 100 degrees C). This allows a complete analysis of the thermodynamics of helix formation. The helix unfolding is found to proceed with a small positive heat-capacity increment, consistent with the solvation of some non-polar groups upon helix unfolding. It follows that the hydrogen bonds are not the only factors responsible for the formation of the alpha-helix, and that hydrophobic interactions are also playing a role in its stabilization. At 30 degrees C, the calorimetric enthalpy and entropy values are estimated to be 650(+/-50) cal mol(-1)and 2.0(+/-0.2) cal K(-1)mole(-1), respectively, per residue of this peptide. Comparison with the thermodynamic characteristics obtained for the unfolding of double-stranded alpha-helical coiled-coils shows that at that temperature the enthalpic contribution of non-polar groups to the stabilization of the alpha-helix is insignificant and the estimated transition enthalpy can be assigned to the hydrogen bonds. With increasing temperature, the increasing magnitude of the negative enthalpy of hydration of the exposed polar groups should decrease the helix-stabilizing enthalpy of the backbone hydrogen bonds. However, the helix-stabilizing negative entropy of hydration of these groups should also increase in magnitude with increasing temperature, offsetting this effect. PMID:10452900

  19. XAFS Model Compound Library

    DOE Data Explorer

    Newville, Matthew

    The XAFS Model Compound Library contains XAFS data on model compounds. The term "model" compounds refers to compounds of homogeneous and well-known crystallographic or molecular structure. Each data file in this library has an associated atoms.inp file that can be converted to a feff.inp file using the program ATOMS. (See the related Searchable Atoms.inp Archive at http://cars9.uchicago.edu/~newville/adb/) This Library exists because XAFS data on model compounds is useful for several reasons, including comparing to unknown data for "fingerprinting" and testing calculations and analysis methods. The collection here is currently limited, but is growing. The focus to date has been on inorganic compounds and minerals of interest to the geochemical community. [Copied, with editing, from http://cars9.uchicago.edu/~newville/ModelLib/

  20. Ecotoxicology of organofluorous compounds.

    PubMed

    Murphy, Margaret B; Loi, Eva I H; Kwok, Karen Y; Lam, Paul K S

    2012-01-01

    Organofluorous compounds have been developed for myriad purposes in a variety of fields, including manufacturing, industry, agriculture, and medicine. The widespread use and application of these compounds has led to increasing concern about their potential ecological toxicity, particularly because of the stability of the C-F bond, which can result in chemical persistence in the environment. This chapter reviews the chemical properties and ecotoxicology of four groups of organofluorous compounds: fluorinated refrigerants and propellants, per- and polyfluorinated compounds (PFCs), fluorinated pesticides, and fluoroquinolone antibiotics. These groups vary in their environmental fate and partitioning, but each raises concern in terms of ecological risk on both the regional and global scale, particularly those compounds with long environmental half-lives. Further research on the occurrence and toxicities of many of these compounds is needed for a more comprehensive understanding of their ecological effects. PMID:21952849

  1. Isolation of Compounds.

    PubMed

    2016-01-01

    Plants are the storehouse of many chemical compounds that possess various biological activities. Identification of these compounds becomes critical in understanding the exact mechanism behind the therapeutic potential of these plants. Screening and isolation of compounds from plants important to human health involves various methods that need careful handling and attention. A detailed method of isolation using thin layer chromatography (TLC) and column is explained. PMID:26939288

  2. Preparation of uranium compounds

    DOEpatents

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

    2013-02-19

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

  3. Nitrodifluoraminoterphenyl compounds and processes

    DOEpatents

    Lerom, M.W.; Peters, H.M.

    1975-07-08

    This patent relates to the nitrodifluoraminoterphenyl compounds: 3,3''-bis (difluoramino)-2,2'' 4,4', 4'',6,6',6''-octanitro-m-terphenyl (DDONT) and 3,3''-bis(difluoramino)-2,2',2''4,4',4'',6,6',6''-nonanitro-m-terphenyl (DDNONA). Procedures are described wherein diamino precursors of the indicated compounds are prepared and the final compounds are obtained by a fluorination operation. The compounds are highly energetic and suitable for use as explosives and particularly in exploding bridge wire (EBW) detonators. (auth)

  4. PREFACE: Sensors & their Applications XVI

    NASA Astrophysics Data System (ADS)

    Kyriacou, Panicos; O'Riordan, Alan

    2011-08-01

    This volume records the Proceedings of the sixteenth conference in the biennial Sensors and Their Applications series which took place at the Clarion Hotel, Cork, Ireland between 12-14 September 2011. The conference is organized by the Instrument Science and Technology Group of the Institute of Physics. On this occasion, the conference was hosted by Tyndall National Institute at University College Cork. This year the conference returns to Ireland, having last been held in Limerick in 2003. The conference proceedings record the continuing growth of the sensors community nationally and internationally. The conferences bring together contributions from scientists and engineers from academia, research institutes and industrial establishments, and therefore provide an excellent opportunity for these communities to present and discuss the latest results in the field of sensors, instrumentation and measurement. Amongst the more traditional themes, such as optical sensing, there is growth in new areas such as biomedical sensing and instrumentation, and nanosensing, which is reflected in this volume. Similarly the contribution of modelling and simulation techniques in sensor and instrumentation design and their applications is acknowledged by a session in this area. The sessions across the conference are supported by notable contributions from invited speakers. We would like to thank all of our colleagues in the sensor and instrumentation community who have supported this event by contributing manuscripts. Our thanks also go to Tyndall National Institute for hosting this conference and all the sponsors who, with their generous financial and in-kind contributions, enabled the better organization of this conference. We would also like to thank all the members of the Instrument Science and Technology Group for their support, and in particular for refereeing the submitted manuscripts. We are also pleased to express our thanks to the Conference Department of the Institute of Physics for their invaluable support in organising this event. We are especially grateful to Dawn Stewart for her responsive and efficient day-to-day handling of this event, as well as to Claire Garland for her planning and management of this event. We hope that the conference authors, participants and a wider audience will find these proceedings to be of interest and to serve as a useful reference text. Panicos KyriacouConference ChairmanAlan O'RiordanConference Local Chairman

  5. Ferric ion (hydr)oxo clusters in the "Venus flytrap" cleft of FbpA: Mössbauer, calorimetric and mass spectrometric studies.

    PubMed

    Mukherjee, Arindam; Bilton, Paul R; Mackay, Logan; Janoschka, Adam; Zhu, Haizhong; Rea, Dean; Langridge-Smith, Pat R R; Campopiano, Dominic J; Teschner, Thomas; Trautwein, Alfred X; Schünemann, Volker; Sadler, Peter J

    2012-04-01

    Isothermal calorimetric studies of the binding of iron(III) citrate to ferric ion binding protein from Neisseria gonorrhoeae suggested the complexation of a tetranuclear iron(III) cluster as a single step binding event (apparent binding constant K(app) (ITC) = 6.0(5) × 10(5) M(-1)). High-resolution Fourier transform ion cyclotron resonance mass spectrometric data supported the binding of a tetranuclear oxo(hydroxo) iron(III) cluster of formula [Fe(4)O(2)(OH)(4)(H(2)O)(cit)](+) in the interdomain binding cleft of FbpA. The mutant H9Y-nFbpA showed a twofold increase in the apparent binding constant [K(app) (ITC) = 1.1(7) × 10(6) M(-1)] for the tetranuclear iron(III) cluster compared to the wild-type protein. Mössbauer spectra of Escherichia coli cells overexpressing FbpA and cultured in the presence of added (57)Fe citrate were indicative of the presence of dinuclear and polynuclear clusters. FbpA therefore appears to have a strong affinity for iron clusters in iron-rich environments, a property which might endow the protein with new biological functions. PMID:22349975

  6. Thermally induced rearrangement of hydrogen-bonded helices in solid 4-isopropylphenol as studied by calorimetric, proton NMR, dielectric and near IR spectroscopic methods

    NASA Astrophysics Data System (ADS)

    Wójcik, G.; Szostak, M. M.; Misiaszek, T.; Pająk, Z.; Wąsicki, J.; Kołodziej, H. A.; Freundlich, P.

    1999-11-01

    Calorimetric, dielectric and Fourier transform near infrared (IR) spectroscopic methods were used to study molecular dynamics and structural transition in solid 4-isopropylphenol (4IP) above room temperature. Pulse proton nuclear magnetic resonance (NMR) measurements were performed in the 100-340 K temperature range. A phase transition was found at 331.5 K, 1.5 K below the melting point. Energetically inequivalent methyl groups reorientations were observed in differently prepared samples and this suggested that a high-temperature polymorph occurs below the transition point as a metastable phase. Dielectric relaxation measurements showed an electric conductivity similar in value to that in water. This was detected as a pronounced contribution to the imaginary part of dielectric permittivity at temperatures higher than 310 K. Near IR spectra revealed that hydrogen bondings are stronger in the high-temperature phase than in the room-temperature-stable one. We propose that thermally induced molecular rearrangements enable proton transfer in hydrogen bonds (HBs) and this stimulates protonic conduction.

  7. Calorimetric study of crystal growth of ice in hydrated methemoglobin and of redistribution of the water clusters formed on melting the ice.

    PubMed Central

    Sartor, G; Mayer, E

    1994-01-01

    Calorimetric studies of the melting patterns of ice in hydrated methemoglobin powders containing between 0.43 and 0.58 (g water)/(g protein), and of their dependence on annealing at subzero temperatures and on isothermal treatment at ambient temperature are reported. Cooling rates were varied between approximately 1500 and 5 K min-1 and heating rate was 30 K min-1. Recrystallization of ice during annealing is observed at T > 228 K. The melting patterns of annealed samples are characteristically different from those of unannealed samples by the shifting of the melting temperature of the recrystallized ice fraction to higher temperatures toward the value of "bulk" ice. The "large" ice crystals formed during recrystallization melt on heating into "large" clusters of water whose redistribution and apparent equilibration is followed as a function of time and/or temperature by comparison with melting endotherms. We have also studied the effect of cooling rate on the melting pattern of ice with a methemoglobin sample containing 0.50 (g water)/(g protein), and we surmise that for this hydration cooling at rates of > or = approximately 150 K min-1 preserves on the whole the distribution of water molecules present at ambient temperature. PMID:7819504

  8. Toxicity of nitroaromatic compounds

    SciTech Connect

    Rickert, D.E.

    1985-01-01

    The contents of this book include: Sex, Strain, and Species Differences in the Response of Rodents to Nitrobenzene Vapors; The Hepatocarcinogenicity of Dinitrotoluenes; Free Radical Mechanism of Nitroreductase; Use of an In Vivo DNA Repair Assay in the Study of Genotoxicity of Nitroaromatic Compounds; and Possible Models for Risk Assessment of Nitroaromatic Compounds.

  9. Understanding Mixed Sequence DNA Recognition by Novel Designed Compounds: The Kinetic and Thermodynamic Behavior of Azabenzimidazole Diamidines

    PubMed Central

    2015-01-01

    Sequence-specific recognition of DNA by small organic molecules offers a potentially effective approach for the external regulation of gene expression and is an important goal in cell biochemistry. Rational design of compounds from established modules can potentially yield compounds that bind strongly and selectively with specific DNA sequences. An initial approach is to start with common A·T bp recognition molecules and build in G·C recognition units. Here we report on the DNA interaction of a synthetic compound that specifically binds to a G·C bp in the minor groove of DNA by using an azabenzimidazole moiety. The detailed interactions were evaluated with biosensor-surface plasmon resonance (SPR), isothermal calorimetric (ITC), and mass spectrometry (ESI-MS) methods. The compound, DB2277, binds with single G·C bp containing sequences with sub-nanomolar potency and displays slow dissociation kinetics and high selectivity. A detailed thermodynamic and kinetic study at different experimental salt concentrations and temperatures shows that the binding free energy is salt concentration dependent but essentially temperature independent under our experimental conditions, and binding enthalpy is temperature dependent but salt concentration independent. The results show that in the proper compound structural context novel heterocyclic cations can be designed to strongly recognize complex DNA sequences. PMID:25495885

  10. Extraction of Bioactive Compounds.

    PubMed

    2016-01-01

    A bioactive compound influences the health of living organisms and it has extranutritional constituents that typically occur in low quantities in foods, which helps to enhance or boost the immune system. Plants and their products possess bioactive compounds, i.e., secondary metabolites. Here, extraction is an important process to isolate the bioactive compounds. Biological activities of the extract show a significant variation depending on the extraction methods and this also opens a gateway for selecting suitable extraction methods. Hence, different extraction methods have been discussed in this section, which influences the extraction of phytochemicals. PMID:26939260

  11. Improving ITC studies of cyclodextrin inclusion compounds by global analysis of conventional and non-conventional experiments

    PubMed Central

    Bertaut, Eléonore

    2014-01-01

    Summary The study of 1:1 cyclodextrin inclusion compounds by isothermal titration calorimetry was explored in a theoretical and experimental point of view to compare the efficiency of conventional and non-conventional experiments. All direct and competitive protocols were described and evaluated in terms of accuracy on both binding constant and inclusion enthalpy. Significant improvement in the calorimetric characterization may be obtained by means of the global analysis of non-conventional experiments coupled to the standard titration protocol. While the titration-release approach proved to be the most accurate strategy for classical complexations, the valuable contribution of other non-conventional experiments was demonstrated for issues concerning weak stability, enthalpy, or solubility. PMID:25550724

  12. Anti-Fog Compound

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Tracer Chemical Corporation's TRX Anti-Fog Composition is an inexpensive product which prevents condensation on plastic and glass surfaces. It was the result from a Tech Briefs article detailing a Johnson Space Center compound.

  13. Heart testing compound

    DOEpatents

    Knapp, F.F. Jr.; Goodman, M.M.

    1983-06-29

    The compound 15-(p-(/sup 125/I)-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  14. Heart testing compound

    DOEpatents

    Knapp, Jr., Furn F.; Goodman, Mark M.

    1985-01-01

    The compound 15-(p-[.sup.125 I]-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  15. Compound composite odontoma

    PubMed Central

    Girish, G; Bavle, Radhika M; Singh, Manish Kumar; Prasad, Sahana N

    2016-01-01

    The term odontoma has been used as a descriptor for any tumor of odontogenic origin. It is a growth in which both epithelial and mesenchymal cells exhibits complete differentiation. Odontomas are considered as hamartomas rather than true neoplasm. They are usually discovered on routine radiographic examination. Odontomas, according to the World Health Organization, are classified into complex odontoma and compound odontomas. The present paper reports a case of compound composite odontomas. PMID:27194882

  16. Compound composite odontoma.

    PubMed

    Girish, G; Bavle, Radhika M; Singh, Manish Kumar; Prasad, Sahana N

    2016-01-01

    The term odontoma has been used as a descriptor for any tumor of odontogenic origin. It is a growth in which both epithelial and mesenchymal cells exhibits complete differentiation. Odontomas are considered as hamartomas rather than true neoplasm. They are usually discovered on routine radiographic examination. Odontomas, according to the World Health Organization, are classified into complex odontoma and compound odontomas. The present paper reports a case of compound composite odontomas. PMID:27194882

  17. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

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

  18. Phenolic Molding Compounds

    NASA Astrophysics Data System (ADS)

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

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

  19. Interaction of cationic dodecyl-trimethyl-ammonium bromide with oxy-HbGp by isothermal titration and differential scanning calorimetric studies: Effect of proximity of isoelectric point.

    PubMed

    Alves, Fernanda Rosa; Carvalho, Francisco Adriano O; Carvalho, José Wilson P; Tabak, Marcel

    2016-04-01

    In this work, isothermal titration and differential scanning calorimetric methods, in combination with pyrene fluorescence emission and dynamic light scattering have been used to investigate the interaction of dodecyltrimethylammonium bromide (DTAB) with the giant extracellular Glossoscolex paulistus hemoglobin (HbGp) in the oxy-form, at pH values around the isoelectric point (pI ≈ 5.5). Our ITC results have shown that the interaction of DTAB with the hemoglobin is more intense at pH 7.0, with a smaller cac (critical aggregation concentration) value. The increase of protein concentration does not influence the cac value of the interaction, at both pH values. Therefore, the beginning of the DTAB-oxy-HbGp premicellar aggregates formation, in the cac region, is not affected by the increase of protein concentration. HSDSC studies show higher Tm values at pH 5.0, in the absence and presence of DTAB, when compared with pH 7.0. Furthermore, at pH 7.0, an aggregation process is observed with DTAB in the range from 0.75 to 1.5 mmol/L, noticed by the exothermic peak, and similar to that observed for pure oxy-HbGp, at pH 5.0, and in the presence of DTAB. DLS melting curves show a decrease on the hemoglobin thermal stability for the oxy-HbGp-DTAB mixtures and formation of larger aggregates, at pH 7.0. Our present data, together with previous results, support the observation that the protein structural changes, at pH 7.0, occur at smaller DTAB concentrations, as compared with pH 5.0, due to the acidic pI of protein that favors the oxy-HbGp-cationic surfactant interaction at neutral pH. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 199-211, 2016. PMID:26574155

  20. Highly trifluoromethylated platinum compounds.

    PubMed

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

    2011-07-11

    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date. PMID:21647991

  1. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

  2. The use of selective extraction chromatographic columns as an alternative to solvent extraction for the separation of uranium followed by the use of Arsenazo III as a calorimetric reagent for uranium determination

    SciTech Connect

    Miller, C.J.; Del Mastro, J.R.

    1994-10-01

    The use of U/TEVA{reg_sign} Spec columns as an alternative to solvent extraction for separation of uranium prior to its determination by various techniques (calorimetric, phosphorescence, and mass spectroscopy) was investigated. U/TEVA{reg_sign} Spec columns have several advantages over the widely used 4-methyl-2-pentanone solvent extraction method. Among the advantages are: (1) no hazardous liquid organic waste, that creates regulatory waste disposal problems, is generated; (2) a clean separation of U from Zr, F, and fission products is obtained; (3) the sample preparation time is reduced; and (4) the exposure of analysts to ionizing radiation is reduced because the entire procedure may be performed in a hot cell using remote operations. This study also investigated the use of Arsenazo III (1,8-dihydroxynapthalene-3,6-disulfonic acid-2,7-bis [<-azo-2>-phenylarsonic acid]) as a calorimetric reagent to determine uranium concentrations over a wide range in waste streams and product streams at the Idaho Chemical Processing Plant. Process and waste stream samples were passed through a U/TEVA{reg_sign} Spec column to selectively remove the uranium. The uranium bearing fraction is compatible with the pH range for color development with Arsenazo III. Arsenazo III may be added to the uranium fraction, at a 3:1 mole ratio (Arsenazo:Uranium) at the high end of the method (10 {mu}/mL). Arsenazo III forms a highly stable complex with uranium. Stability tests from this and other studies show that the colored complex of Arsenazo III with U(VI) forms within one minute and remains stable for several hours. The complex with U(VI) varies in color with pH. However, with excess reagent, the color is varying shades of purple. Since the samples were passed through a highly selective extraction chromatographic column prior to adding the calorimetric reagent, no interferences were observed.

  3. Metalloid compounds as drugs.

    PubMed

    Sekhon, B S

    2013-07-01

    The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O'-)tellurate (AS101) may be a promising agent for the treatment of Parkinson's disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents. PMID:24019824

  4. Sulfur compounds in coal

    NASA Technical Reports Server (NTRS)

    Attar, A.; Corcoran, W. H.

    1977-01-01

    The literature on the chemical structure of the organic sulfur compounds (or functional groups) in coal is reviewed. Four methods were applied in the literature to study the sulfur compounds in coal: direct spectrometric and chemical analysis, depolymerization in drastic conditions, depolymerization in mild conditions, and studies on simulated coal. The data suggest that most of the organic sulfur in coal is in the form of thiophenic structures and aromatic and aliphatic sulfides. The relative abundance of the sulfur groups in bituminous coal is estimated as 50:30:20%, respectively. The ratio changes during processing and during the chemical analysis. The main effects are the transformation during processing of sulfides to the more stable thiophenic compounds and the elimination of hydrogen sulfide.

  5. Metalloid compounds as drugs

    PubMed Central

    Sekhon, B. S.

    2013-01-01

    The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O’-)tellurate (AS101) may be a promising agent for the treatment of Parkinson’s disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents. PMID:24019824

  6. Microoptical compound lens

    DOEpatents

    Sweatt, William C.; Gill, David D.

    2007-10-23

    An apposition microoptical compound lens comprises a plurality of lenslets arrayed around a segment of a hollow, three-dimensional optical shell. The lenslets collect light from an object and focus the light rays onto the concentric, curved front surface of a coherent fiber bundle. The fiber bundle transports the light rays to a planar detector, forming a plurality of sub-images that can be reconstructed as a full image. The microoptical compound lens can have a small size (millimeters), wide field of view (up to 180.degree.), and adequate resolution for object recognition and tracking.

  7. Fluoroalkylation of organic compounds

    NASA Astrophysics Data System (ADS)

    Mikhaylov, D. Yu; Budnikova, Yu H.

    2013-09-01

    Data on fluoroalkylation and perfluoroalkylation methods in organic synthesis are analyzed, summarized and described systematically. The most practically important properties of compounds with fluoroalkyl substituents are illustrated. The key trends and the potential of this field of organic chemistry are considered. Electrochemical syntheses of perfluoroalkyl derivatives that are inaccessible or experimentally difficult to prepare by regular chemical techniques are presented. Particular attention is paid to processes involving organometallic compounds as well as to prospects for the development of this field of research. The bibliography includes 226 references.

  8. Monitoring dehydration of the organic-inorganic [(C3H7)4N][SnCl5(H2O)]·2H2O compound using simultaneous thermal and Raman studies.

    PubMed

    Hajlaoui, S; Chaabane, I; Guidara, K; Bulou, A

    2016-07-01

    In this work we report the experimental studies of the structural phase transition in the [(C3H7)4N]SnCl5(H2O)]·2H2O compound by differential scanning calorimetric (DSC) and Raman spectroscopic. The X-ray powder diffraction study of the [(C3H7)4N][SnCl5(H2O)]·2H2O sample at room temperature showed that this compound is monoclinic and has P121/c1 space group. Differential scanning calorimetric disclosed two types of phase transitions in the temperature range 356-376 (T1) K and at 393K (T2) characterized, by a loss of water molecules and probably a reconstruction of new anionic parts after T2 transition. The Raman scattering spectra recorded at various temperatures in the wavenumber range from 100 to 3800cm(-1) covering the domains of existence of changes in the vicinity of the two phase transitions detected by DSC measurement. A detailed study of the spectral parameters (wave number, reduced intensity and the full width at half maximum) as a function of temperature of a chosen band, associated with (νs(SnO)+νs(SnCl)), based on an order-disorder model allowed us to obtain information relative to the activation energy and correlation length. PMID:27070530

  9. Crystal growth, complex phase diagram and high pressure studies of layer compound PdBi2

    NASA Astrophysics Data System (ADS)

    Zhao, Kui; Zhu, Xiyu; Lv, Bing; Xue, Yuyi; Chu, Paul

    2013-03-01

    Among the different Pd-Bi Alloys, β-PdBi2, which is crystallized in a layered tetragonal (I4/mmm) structure, has been identified as a superconductor with transition temperature at ~ 5.4K. Band structure calculation indicates that the interlayer Bi-Bi bonds are weak but not negligible, which implies the 3D bonding character of this compound. In order to enhance or weaken the interlayer bonding and ultimately increase the Tc in this system, high pressure measurement, isovalent chemical substitution of Bi with Sb, and chemical intercalation using transition metal Cu and alkali metal Na, are applied to the system. Meanwhile, aliovalent chemical substitution on the Bi site by Pb is also carried out. The magnetic, electrical, and calorimetric properties of these compounds are determined at ambient pressure and compared. The detailed high pressure results and the complete phase diagram of chemical substitution and intercalation will be presented and discussed. Work in Houston is supported in part by US AFOSR, the State of Texas, T. L. L. Temple Foundation and John and Rebecca Moores Endowment.

  10. Temperature-Dependent Structure-Energy Changes in Crystals of Compounds with Poly(hydroxymethyl) Grouping

    NASA Astrophysics Data System (ADS)

    Golovina, N. I.; Raevskii, A. V.; Fedorov, B. S.; Chukanov, N. V.; Shilov, G. V.; Leonova, L. S.; Tarasov, V. P.; Erofeev, L. N.

    2002-03-01

    Crystals of tris(hydroxymethyl)nitromethane (1) and tris(hydroxymethyl)aminomethane (2) were prepared and grown at room temperature. X-ray analysis was used to study the structure of crystals 1 and 2 at room temperature; the X-ray diffraction method was applied to investigate polycrystalline samples during a temperature rise up to the phase transition into the plastic phase. Phase transitions in separate crystals 1 and 2 were observed in a hot stage under an optical microscope. Calorimetric study of the crystal temperature behavior and the phase transition features including melting were carried out. By IR spectroscopy the temperature relations of the bonds of symmetric N-O stretching vibrations of nitro groups and stretching vibrations of OH groups redistribution in crystals of 1 were investigated. In crystals of 2 the behavior of stretching vibration bands of O-H groups was studied at room temperature. In the temperature interval including phase transition, data on structure-dynamic rearrangements in the crystal lattice of compounds 1 and 2 were obtained by the NMR pulse method in the solid phase using relaxational free induction decay of protons. The proton conductivity was found and its temperature parameters were determined for both compounds in the plastic state.

  11. Electrical properties and phase transition of [(CH3)3NH]CdCl3 compound

    NASA Astrophysics Data System (ADS)

    Kchaou, H.; Ben Rhaiem, A.; Karoui, K.; jomni, F.; Guidara, K.

    2016-02-01

    The [(CH3)3NH]CdCl3 compound was obtained by slow evaporation at room temperature and characterized by X-ray powder diffraction patterns, differential scanning calorimetry, and impedance spectroscopy. This compound was found to crystallize in the orthorhombic system with Pbnm space group and was characterized by four phase transitions ( T 1 = 355 K, T 2 = 372 K, T 3 = 415 K, and T 4 = 446 K). The analysis of Nyquist plots has revealed the contribution of two electrically active regions corresponding to the bulk mechanism and distribution of grain boundaries. The modulus plots were characterized by the presence of two peaks associated with the grain and grain boundaries. Thermodynamic parameters such as the free energy for dipole relaxation ? F, the enthalpy ? H, and the change in entropy ? S h ave been determined with the help of the Eyring theory. The temperature dependence of the electrical conductivity (? g ), ? dc , and f p confirms the observed transitions in the calorimetric study.

  12. Analyzing cranberry bioactive compounds.

    PubMed

    Côté, J; Caillet, S; Doyon, G; Sylvain, J-F; Lacroix, M

    2010-10-01

    There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit--the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a sample matrix is a prerequisite to any comprehensive analysis scheme. By far the most widely employed analytical technique for the characterization of these compounds has been high-performance liquid chromatography(HPLC) coupled with ultraviolet-visible(UV/Vis) and mass spectrometer(MS) detection. This review covers the cranberry major bioactive compounds, the extraction and purification methods, and the analytical conditions for HPLC used to characterize them. Extraction, chromatographic separation and detection strategies, analyte determinations, and applications in HPLC are discussed and the information regarding methods of specific cranberry analyte analyses has been summarized in tabular form to provide a means of rapid access to information pertinent to the reader. PMID:20924868

  13. Beryllium and compounds

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 98 / 008 TOXICOLOGICAL REVIEW OF BERYLLIUM AND COMPOUNDS ( CAS No . 7440 - 41 - 7 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) April 1998 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed in acco

  14. PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

  15. Urinary Compounds in Autism

    ERIC Educational Resources Information Center

    Alcorn, A.; Berney, T.; Bretherton, K.; Mills, M.; Savery, D.; Shattock, P.

    2004-01-01

    Although earlier claims to identify specific compounds in the urine of people with autism had been discredited, it was subsequently suggested that there might be biochemical characteristics that were specific to early childhood, particularly in those who also did not have a severe degree of intellectual disability This study was to establish…

  16. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  17. 8-fluoropurine compounds

    DOEpatents

    Barrio, Jorge R.; Satyamurthy, Nagichettiar; Namavari, Mohammad; Phelps, Michael E.

    2001-01-01

    An efficient, regiocontrolled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F.sub.2 in He or other inert gas.

  18. Aminopropyl thiophene compounds

    DOEpatents

    Goodman, Mark M.; Knapp, Jr., Furn F.

    1990-01-01

    Radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation of regional blood flow by radioimaging of the brain.

  19. Barium and Compounds

    Integrated Risk Information System (IRIS)

    Barium and Compounds ; CASRN 7440 - 39 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  20. Zinc and Compounds

    Integrated Risk Information System (IRIS)

    Zinc and Compounds ; CASRN 7440 - 66 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

  1. Selenium and Compounds

    Integrated Risk Information System (IRIS)

    Selenium and Compounds ; CASRN 7782 - 49 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  2. Boron and Compounds

    Integrated Risk Information System (IRIS)

    Boron and Compounds ; CASRN 7440 - 42 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  3. Lead and compounds (inorganic)

    Integrated Risk Information System (IRIS)

    Lead and compounds ( inorganic ) ; CASRN 7439 - 92 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  4. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help

  5. A stable argon compound

    NASA Astrophysics Data System (ADS)

    Khriachtchev, Leonid; Pettersson, Mika; Runeberg, Nino; Lundell, Jan; Räsänen, Markku

    2000-08-01

    The noble gases have a particularly stable electronic configuration, comprising fully filled s and p valence orbitals. This makes these elements relatively non-reactive, and they exist at room temperature as monatomic gases. Pauling predicted in 1933 that the heavier noble gases, whose valence electrons are screened by core electrons and thus less strongly bound, could form stable molecules. This prediction was verified in 1962 by the preparation of xenon hexafluoroplatinate, XePtF6, the first compound to contain a noble-gas atom. Since then, a range of different compounds containing radon, xenon and krypton have been theoretically anticipated and prepared. Although the lighter noble gases neon, helium and argon are also expected to be reactive under suitable conditions, they remain the last three long-lived elements of the periodic table for which no stable compound is known. Here we report that the photolysis of hydrogen fluoride in a solid argon matrix leads to the formation of argon fluorohydride (HArF), which we have identified by probing the shift in the position of vibrational bands on isotopic substitution using infrared spectroscopy. Extensive ab initio calculations indicate that HArF is intrinsically stable, owing to significant ionic and covalent contributions to its bonding, thus confirming computational predictions that argon should form a stable hydride species with properties similar to those of the analogous xenon and krypton compounds reported before.

  6. Compound floating pivot micromechanisms

    DOEpatents

    Garcia, Ernest J.

    2001-04-24

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

  7. The Onium Compounds

    NASA Astrophysics Data System (ADS)

    Tsarevsky, Nicolay V.; Slaveykova, Vera; Manev, Stefan; Lazarov, Dobri

    1997-06-01

    The onium salts are of a big interest for theoretical and structural chemistry, and for organic synthesis. Some representatives of the group (e.g. ammonium salts) were known from the oldest times. Many onium salts are met the nature: ammonium salts (either as inorganic salts, and organic derivatives, e.g. aminoacids, salts of biogenic amines and alkaloids, etc.); oxonium salts (plant pigments as anthocyans are organic oxonium compounds), etc. In 1894 C. Hartmann and V. Meyer prepared the first iodonium salts - 4-iododiphenyliodonium hydrogensulfate and diphenyliodonium salts, and suggested the ending -onium for all compounds with properties similar to those of ammonium salts. Nowadays onium compounds of almost all nonmetals are synthesised and studied. A great variety of physical methods: diffraction (e.g. XRD) and spectral methods (IR-, NMR-, and UV-spectra), as well as the chemical properties and methods of preparation of onium salts have been used in determination of the structure of these compounds. The application of different onium salts is immense. Ammonium, phosphonium and sulfonium salts are used as phase-transfer catalysts; diazonium salts - for the preparation of dyes, metalochromic and pH-indicators. All the onium salts and especially diazonium and iodonium salts are very useful reagents in organic synthesis.

  8. Rhombohedral nasicon compound and battery

    SciTech Connect

    Yoldas, B. E.; Lioyd, I. K.

    1985-07-02

    Disclosed is a nasicon compound and a method of making it. The nasicon compound is rhombohedral at room temperture. The preferred compound is Na/sub 1//sub +/ /SUB x/ Zr/sub 2/Si /SUB x/ P/sub 3//sub -/ /SUB x/ O/sub 12/. A sodium sulfur battery using the nasicon compound is also disclosed.

  9. Protonation and Complexation of Isosaccharinic Acid with U(VI) and Fe(III) in Acidic Solutions: Potentiometric and Calorimetric Studies

    SciTech Connect

    Rao, Linfeng; Garnov, A Y.; Rai, Dhanpat; Xia, Yuanxian; Moore, R C.

    2004-12-01

    Protonation and complexation of {alpha}-isosaccharinic acid with U(VI) and Fe(III) have been studied in acidic solutions at t=25 C and I=1.0 mol dm{sup -3} NaClO{sub 4}. From the potentiometric titrations, the protonation constant of the carboxylate group is calculated to be 3.65 {+-} 0.05 and the data are consistent with the presence of three and four successive mononuclear complexes for U(VI) and Fe(III), respectively. The formation constants of the complexes, log {beta}{sub j}for the reactions of M+L=ML{sub j} where j=1-3 for U(VI), j=1-4 for Fe(III) and L stands for isosaccharinate, are determined to be 2.91 {+-} 0.15 (UO{sub 2}L), 5.37 {+-} 0.07 (UO{sub 2}L{sub 2}), 7.25 {+-} 0.18 (UO{sub 2}L{sub 3}), 5.06 {+-} 0.17 (FeL), 8.51 {+-} 0.15 (FeL{sub 2}), 11.00 {+-} 0.16 (FeL{sub 3}), and 12.99 {+-} 0.17 (FeL{sub 4}). From the calorimetric titrations, the enthalpy of protonation of the carboxylate group is determined to be -(7.94 {+-} 0.03)kJ mol{sup -1}, similar to that of other ?-hydroxycarboxylates. The enthalpies of complexation between U(VI) and isosaccharinate are quite small: {Delta} H{sub 1} = -(1.0 {+-} 1.0)kJ mol{sup -1}, {Delta} H{sub 2}=1.4 {+-} 1.8 kJ mol{sup -1} and {Delta} H{sub 3}=-(6.2 {+-} 3.0)kJ mol{sup -1}, typical of the interactions between carboxylates and hard-acid cations. The complexation between U(VI) and isosaccharinate is mainly entropy-driven. In comparison, the enthalpies of complexation for FeL{sub 3} and FeL{sub 4} are large and exothermic, contributing significantly to the stability of the complexes.

  10. Non-exponential nature of calorimetric and other relaxations: Effects of 2 nm-size solutes, loss of translational diffusion, isomer specificity, and sample size

    NASA Astrophysics Data System (ADS)

    Johari, G. P.; Khouri, J.

    2013-03-01

    Certain distributions of relaxation times can be described in terms of a non-exponential response parameter, β, of value between 0 and 1. Both β and the relaxation time, τ0, of a material depend upon the probe used for studying its dynamics and the value of β is qualitatively related to the non-Arrhenius variation of viscosity and τ0. A solute adds to the diversity of an intermolecular environment and is therefore expected to reduce β, i.e., to increase the distribution and to change τ0. We argue that the calorimetric value βcal determined from the specific heat [Cp = T(dS/dT)p] data is a more appropriate measure of the distribution of relaxation times arising from configurational fluctuations than β determined from other properties, and report a study of βcal of two sets of binary mixtures, each containing a different molecule of ˜2 nm size. We find that βcal changes monotonically with the composition, i.e., solute molecules modify the nano-scale composition and may increase or decrease τ0, but do not always decrease βcal. (Plots of βcal against the composition do not show a minimum.) We also analyze the data from the literature, and find that (i) βcal of an orientationally disordered crystal is less than that of its liquid, (ii) βcal varies with the isomer's nature, and chiral centers in a molecule decrease βcal, and (iii) βcal decreases when a sample's thickness is decreased to the nm-scale. After examining the difference between βcal and β determined from other properties we discuss the consequences of our findings for theories of non-exponential response, and suggest that studies of βcal may be more revealing of structure-freezing than studies of the non-Arrhenius behavior. On the basis of previous reports that β → 1 for dielectric relaxation of liquids of centiPoise viscosity observed at GHz frequencies, we argue that its molecular mechanism is the same as that of the Johari-Goldstein (JG) relaxation. Its spectrum becomes broader on cooling and its unimodal distribution reversibly changes to a bimodal distribution, each of β < 1. Kinetic freezing of the slower modes of the bimodal distribution produces a glass. After this bifurcation, the faster, original relaxation persists as a weak JG relaxation at T → Tg, and in the glassy state.

  11. Photofunctions of intercalation compounds

    SciTech Connect

    Ogawa, Makoto; Kuroda, Kazuyuki

    1995-03-01

    In this article, the authors review the studies on the photofunctions of intercalation compounds. (The structures and properties of host materials which have been used for immobilizing photoactive species have been summarized in the following section.) some of these studies are for the purpose of characterizing the properties of host materials and host-guest systems, and others are for the purpose of contributing to future practical applications. The well-defined layered structures as well as the ability to accommodate guest species on the surface of the layers are very useful for organizing photoactive species to evaluate and control the photofunctions. Table 1 summarizes the characteristics of typical host-guest systems studied for immobilizing photoactive species. Attention is mainly focused on the role of layered structure on the organization of photoactive species; the photofunctions of intercalation compounds are discussed only in connection with the microscopic structures. 321 refs.

  12. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.

    1980-01-01

    Recent studies of carbonaceous chondrites provide evidence that certain organic compounds are indigenous and the result of an abiotic, chemical synthesis. The results of several investigators have established the presence of amino acids and precursors, mono- and dicarboxylic acids, N-heterocycles, and hydrocarbons as well as other compounds. For example, studies of the Murchison and Murray meteorites have revealed the presence of at least 40 amino acids with nearly equal abundances of D and L isomers. The population consists of both protein and nonprotein amino acids including a wide variety of linear, cyclic, and polyfunctional types. Results show a trend of decreasing concentration with increasing carbon number, with the most abundant being glycine (41 n Moles/g). These and other results to be reviewed provide persuasive support for the theory of chemical evolution and provide the only natural evidence for the protobiological subset of molecules from which life on earth may have arisen.

  13. High temperature high pressure thermodynamic measurements for coal model compounds. Semiannual technical progress report, September 1, 1995--February 29, 1996

    SciTech Connect

    Kabadi, V.N.; Chen, J.C.

    1996-10-01

    The overall objective of this project is to develop a better thermodynamic model for predicting properties of high-boiling coal derived liquids, especially the phase equilibria of different fractions at elevated temperatures and pressures. The development of such a model requires data on vapor-liquid equilibria (VLE), enthalpy, and heat capacity which would be experimentally determined for binary systems of coal model compounds and compiled into a database. The data will be used to refine existing models such as UNIQUAC and UNIFAC. A M.S. graduate student Mr. Ahmad Al-Ghamdi has been recruited to work on this project. The flow VLE apparatus designed and built for a previous project has been upgraded and recalibrated for data measurements for this project. The modifications include better and more accurate sampling technique and addition of a digital recorder to monitor temperature, pressure and liquid level inside the VLE cell. VLE data measurements for system benzene-ethylbenzene have begun. The vapor and liquid compositions will be measured using the Perkin-Elmer Auto-system gas chromatograph. A capillary column made by Supelco has been purchased for the analysis. For enthalpy and heat capacity measurements, SETARAM C-80 calorimeter has been purchased and installed. The instrument can be used for calorimetric property measurements at temperatures up to 300{degree}C and pressures up to 1500 psi. Enthalpy measurements for the system benzene-ethylbenzene have begun. Simultaneously, we have undertaken the design of a calorimetric cell that will allow enthalpy measurements at pressures up to 10000 psi. In this report the VLE apparatus and the preliminary work completed for the VLE measurements for the benzene-ethylbenzene system are described. A description of the calorimeter and the measured enthalpy data for the benzene-ethylbenzene system will be included in the next report. 3 figs., 5 tabs.

  14. Micro-machined calorimetric biosensors

    DOEpatents

    Doktycz, Mitchel J.; Britton, Jr., Charles L.; Smith, Stephen F.; Oden, Patrick I.; Bryan, William L.; Moore, James A.; Thundat, Thomas G.; Warmack, Robert J.

    2002-01-01

    A method and apparatus are provided for detecting and monitoring micro-volumetric enthalpic changes caused by molecular reactions. Micro-machining techniques are used to create very small thermally isolated masses incorporating temperature-sensitive circuitry. The thermally isolated masses are provided with a molecular layer or coating, and the temperature-sensitive circuitry provides an indication when the molecules of the coating are involved in an enthalpic reaction. The thermally isolated masses may be provided singly or in arrays and, in the latter case, the molecular coatings may differ to provide qualitative and/or quantitative assays of a substance.

  15. Compound chondrules fused cold

    NASA Astrophysics Data System (ADS)

    Hubbard, Alexander

    2015-07-01

    About 4-5% of chondrules are compound: two separate chondrules stuck together. This is commonly believed to be the result of the two component chondrules having collided shortly after forming, while still molten. This allows high velocity impacts to result in sticking. However, at T ∼ 1100 K, the temperature below which chondrules collide as solids (and hence usually bounce), coalescence times for droplets of appropriate composition are measured in tens of seconds. Even at 1025 K, at which temperature theory predicts that the chondrules must have collided extremely slowly to have stuck together, the coalescence time scale is still less than an hour. These coalescence time scales are too short for the collision of molten chondrules to explain the observed frequency of compound chondrules. We suggest instead a scenario where chondrules stuck together in slow collisions while fully solid; and the resulting chondrule pair was subsequently briefly heated to a temperature in the range of 900-1025 K. In that temperature window the coalescence time is finite but long, covering a span of hours to a decade. This is particularly interesting because those temperatures are precisely the critical window for thermally ionized MRI activity, so compound chondrules provide a possible probe into that vital regime.

  16. Antifungal compounds from cyanobacteria.

    PubMed

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

    2015-04-01

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders. PMID:25871291

  17. (Toxic organic compounds)

    SciTech Connect

    Not Available

    1990-01-01

    The general theme of this program has been the identification of potentially toxic organic compounds associated with various combustion effluents, following the fates of these compounds in the environment, and improving the analytical methodology for making these measurements. Over the years, Professor Hites' interest has ranged from polycyclic aromatic hydrocarbons to diesel exhaust to chlorinated dioxins. At the moment, work in his laboratory is increasingly focused on the fundamentals of mass spectrometry although he continues to be interested in environmental processes and measurements. Electron capture, negative ionization, mass spectrometry is a particularly important technique for environmental contaminant analysis. Many such contaminants contain electronegative atoms (such as chlorine); thus, negative ionization techniques provide both high specificity as well as high sensitivity. Her work focused on identifying the instrumental parameters which caused variation both within and between laboratories. It turned out that careful control of ion source lens potentials and temperature and eliminating extraneous oxygen allowed her to achieve reproducible spectra. She studied the fragmentation behavior of about 300 compounds and deduced certain rules of fragmentation. This work resulted in several papers and in a book published by VCH Press. 61 refs.

  18. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1987-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burn for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  19. Antifungal Compounds from Cyanobacteria

    PubMed Central

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

    2015-01-01

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders. PMID:25871291

  20. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1986-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burned for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  1. Toxic compounds in honey.

    PubMed

    Islam, Md Nazmul; Khalil, Md Ibrahim; Islam, Md Asiful; Gan, Siew Hua

    2014-07-01

    There is a wealth of information about the nutritional and medicinal properties of honey. However, honey may contain compounds that may lead to toxicity. A compound not naturally present in honey, named 5-hydroxymethylfurfural (HMF), may be formed during the heating or preservation processes of honey. HMF has gained much interest, as it is commonly detected in honey samples, especially samples that have been stored for a long time. HMF is a compound that may be mutagenic, carcinogenic and cytotoxic. It has also been reported that honey can be contaminated with heavy metals such as lead, arsenic, mercury and cadmium. Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. In addition, Melicope ternata and Coriaria arborea from New Zealand produce toxic honey that can be fatal. There are reports that honey is not safe to be consumed when it is collected from Datura plants (from Mexico and Hungary), belladonna flowers and Hyoscamus niger plants (from Hungary), Serjania lethalis (from Brazil), Gelsemium sempervirens (from the American Southwest), Kalmia latifolia, Tripetalia paniculata and Ledum palustre. Although the symptoms of poisoning due to honey consumption may differ depending on the source of toxins, most common symptoms generally include dizziness, nausea, vomiting, convulsions, headache, palpitations or even death. It has been suggested that honey should not be considered a completely safe food. PMID:24214851

  2. Synthesis, crystal growth and physicochemical studies on a novel organic inter-molecular compound; 3,5-dinitrobenzoic acid and salicylamide system

    NASA Astrophysics Data System (ADS)

    Singh, Manjeet; Rai, R. N.; Rai, U. S.

    2015-06-01

    The phase diagram of salicylamide (SAM) and 3,5-dinitrobenzoic acid (DNBA) system was determined by the thaw-melt method. Results show the formation of an inter-molecular compound and two eutectics. The values of heat of mixing, entropy of fusion, roughness parameter, interfacial energy, and the excess thermodynamic functions were calculated from the enthalpy of fusion data determined by the differential scanning calorimetric (DSC) method. The spectroscopic investigations (IR and NMR) suggest the presence of hydrogen bonding between the components of the compound. A single crystal of the inter-molecular compound was grown using slow cooling technique from the mixed solvent of ethanol and triple distilled water in 2:1 volume ratio. The single crystal analysis and the atomic packing pattern of the grown crystal confirm the monoclinic crystal structure with P21/c space group. The solubility of the inter-molecular compound was determined in the mixed solvent at different temperatures. Using solubility and entropy of fusion data, the entropy of dissolution and heat of mixing were calculated. The optical transmittance spectra of the crystal of the inter-molecular compound show 75% transmittance and the band gap of the crystal was found to be 3.00 eV. The refractive index of the crystal was computed to be 2.50 at the cut off wavelength.

  3. Using Raman spectroscopy to understand the origin of the phase transitions observed in [(C₃H₇)₄N]₂Zn₂Cl₆ compound.

    PubMed

    Ben Gzaiel, M; Oueslati, A; Chaabane, I; Bulou, A; Hlel, F; Gargouri, M

    2015-06-15

    Phase transitions of the centrosymmetric compound, [(C3H7)4N]2Zn2Cl6, were studied by differential scanning calorimetry (DSC), X-ray diffraction, Raman spectroscopy and dielectric measurements. Two reversible order-disorder and displacive phase transitions are observed at T1=327K and T2=347K with 3K and 4K hysteresis respectively, indicating a first order character. The evolution of Raman line shifts, "ν", and the half-width, "Δν", versus temperature show some singularities associated with the transitions, suggesting that they are governed by the reorientational and the displacement of the organic part. Besides the results of the dielectric permittivity study confirms the conclusion drawn from the calorimetric and Raman measurements that the phase transition located in the vicinity of the temperature of the dielectric proprieties is characterized by change of dynamical state of cation. PMID:25782180

  4. Using Raman spectroscopy to understand the origin of the phase transitions observed in [(C3H7)4N]2Zn2Cl6 compound

    NASA Astrophysics Data System (ADS)

    Ben Gzaiel, M.; Oueslati, A.; Chaabane, I.; Bulou, A.; Hlel, F.; Gargouri, M.

    2015-06-01

    Phase transitions of the centrosymmetric compound, [(C3H7)4N]2Zn2Cl6, were studied by differential scanning calorimetry (DSC), X-ray diffraction, Raman spectroscopy and dielectric measurements. Two reversible order-disorder and displacive phase transitions are observed at T1 = 327 K and T2 = 347 K with 3 K and 4 K hysteresis respectively, indicating a first order character. The evolution of Raman line shifts, "ν", and the half-width, "Δν", versus temperature show some singularities associated with the transitions, suggesting that they are governed by the reorientational and the displacement of the organic part. Besides the results of the dielectric permittivity study confirms the conclusion drawn from the calorimetric and Raman measurements that the phase transition located in the vicinity of the temperature of the dielectric proprieties is characterized by change of dynamical state of cation.

  5. Offset Compound Gear Drive

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  6. Oligosilanylated Antimony Compounds

    PubMed Central

    2015-01-01

    By reactions of magnesium oligosilanides with SbCl3, a number of oligosilanylated antimony compounds were obtained. When oligosilanyl dianions were used, either the expected cyclic disilylated halostibine was obtained or alternatively the formation of a distibine was observed. Deliberate formation of the distibine from the disilylated halostibine was achieved by reductive coupling with C8K. Computational studies of Sb–Sb bond energies, barriers of pyramidal inversion at Sb, and the conformational behavior of distibines provided insight for the understanding of the spectroscopic properties. PMID:25937691

  7. Boronated porphyrin compounds

    DOEpatents

    Kahl, S.B.; Koo, M.S.

    1992-09-22

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  8. Boronated porphyrin compounds

    DOEpatents

    Kahl, Stephen B.; Koo, Myoung-Seo

    1992-01-01

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  9. Immunomodulating compounds in Basidiomycetes

    PubMed Central

    Mizuno, Masashi; Nishitani, Yosuke

    2013-01-01

    Mushrooms are distinguished as important food containing immunomodulating and anticancer agents. These compounds belong mostly to polysaccharides especially β-d-glucans. Among them, β-1,3-glucan with side chain β-1,6-glucose residues have more important roles in immunomodulating and antitumor activities. In this review, we have introduced polysaccharide mainly from Lentinula edodes and Agaricus blazei Murill with immunomodulating and antitumor activities. In addition, the mechanism of activation of immune response and signal cascade are also reviewed. PMID:23704809

  10. Titanium alkoxide compound

    DOEpatents

    Boyle, Timothy J.

    2007-08-14

    A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

  11. Superconductivity in iron compounds

    NASA Astrophysics Data System (ADS)

    Stewart, G. R.

    2011-10-01

    Kamihara and coworkers’ report of superconductivity at Tc=26K in fluorine-doped LaFeAsO inspired a worldwide effort to understand the nature of the superconductivity in this new class of compounds. These iron pnictide and chalcogenide (FePn/Ch) superconductors have Fe electrons at the Fermi surface, plus an unusual Fermiology that can change rapidly with doping, which lead to normal and superconducting state properties very different from those in standard electron-phonon coupled “conventional” superconductors. Clearly, superconductivity and magnetism or magnetic fluctuations are intimately related in the FePn/Ch, and even coexist in some. Open questions, including the superconducting nodal structure in a number of compounds, abound and are often dependent on improved sample quality for their solution. With Tc values up to 56 K, the six distinct Fe-containing superconducting structures exhibit complex but often comparable behaviors. The search for correlations and explanations in this fascinating field of research would benefit from an organization of the large, seemingly disparate data set. This review provides an overview, using numerous references, with a focus on the materials and their superconductivity.

  12. Potential risks of pharmacy compounding.

    PubMed

    Gudeman, Jennifer; Jozwiakowski, Michael; Chollet, John; Randell, Michael

    2013-03-01

    Pharmacy compounding involves the preparation of customized medications that are not commercially available for individual patients with specialized medical needs. Traditional pharmacy compounding is appropriate when done on a small scale by pharmacists who prepare the medication based on an individual prescription. However, the regulatory oversight of pharmacy compounding is significantly less rigorous than that required for Food and Drug Administration (FDA)-approved drugs; as such, compounded drugs may pose additional risks to patients. FDA-approved drugs are made and tested in accordance with good manufacturing practice regulations (GMPs), which are federal statutes that govern the production and testing of pharmaceutical products. In contrast, compounded drugs are exempt from GMPs, and testing to assess product quality is inconsistent. Unlike FDA-approved drugs, pharmacy-compounded products are not clinically evaluated for safety or efficacy. In addition, compounded preparations do not have standard product labeling or prescribing information with instructions for safe use. Compounding pharmacies are not required to report adverse events to the FDA, which is mandatory for manufacturers of FDA-regulated medications. Some pharmacies engage in activities that extend beyond the boundaries of traditional pharmacy compounding, such as large-scale production of compounded medications without individual patient prescriptions, compounding drugs that have not been approved for use in the US, and creating copies of FDA-approved drugs. Compounding drugs in the absence of GMPs increases the potential for preparation errors. When compounding is performed on a large scale, such errors may adversely affect many patients. Published reports of independent testing by the FDA, state agencies, and others consistently show that compounded drugs fail to meet specifications at a considerably higher rate than FDA-approved drugs. Compounded sterile preparations pose the additional risk of microbial contamination to patients. In the last 11 years, three separate meningitis outbreaks have been traced to purportedly 'sterile' steroid injections contaminated with fungus or bacteria, which were made by compounding pharmacies. The most recent 2012 outbreak has resulted in intense scrutiny of pharmacy compounding practices and increased recognition of the need to ensure that compounding is limited to appropriate circumstances. Patients and healthcare practitioners need to be aware that compounded drugs are not the same as generic drugs, which are approved by the FDA. The risk-benefit ratio of using traditionally compounded medicines is favorable for patients who require specialized medications that are not commercially available, as they would otherwise not have access to suitable treatment. However, if an FDA-approved drug is commercially available, the use of an unapproved compounded drug confers additional risk with no commensurate benefit. PMID:23526368

  13. Biomimetic microfabricated compound eyes

    NASA Astrophysics Data System (ADS)

    Jeong, Ki-Hun

    2005-11-01

    Over the past century, compound eyes in nature have been one of the most studied and intriguing topics in physiological optics due to their unique optical scheme for imaging. Hundreds to ten thousands of integrated optical units called ommatidia are spherically arranged along a curvilinear surface and point in different directions. Each ommatidium collects light within a small angular acceptance and collectively they construct a full image with a wide field-of-view. In this work, artificial compound eye lenses with three-dimensional configuration, which are anatomically and functionally similar to those in nature, have been synthesized using a photosensitive polymer resin by utilizing microlens technology, self-written waveguide process, and soft lithography. Replicated honeycomb packed polymer microlenses as substitute for facet lenses in a natural compound eye was microfabricated with a photoresist melting process for microlens templates and a soft lithographic process for polymer replication. The microtemplate of photoresist microlens arrays (F/1 ˜ F/3, DL = 20 ˜ 50 mum) with low Fresnel number (NF < 10) and high packing density was replicated with different polymers such as UV curable epoxy resin, polydimethylsiloxane elastomer, and a negative tone photoresist. Related to ommatidial optics, the diffraction of a low Fresnel number microlens, the light guiding of a waveguide, and the angular acceptance function of a microlens-waveguide system were theoretically studied with numerical analysis. First, as a prototype microfabricated microlens-waveguide system ( DL = 300 mum), a small angular acceptance (rho A = 1.5°) comparable to that of natural ommatidia was experimentally achieved and compared with the numerical analysis. The system is based on self-written waveguides in a photosensitive polymer resin and replicated elastomer microlens arrays. However, due to the technical difficulties in handling the elastomer membrane with microlenses, it is limited in scaling down to the physical dimensions of natural ommatidium. Second, as an advanced development, self-aligned microlens-waveguide systems comparable to the physical dimensions of natural ommatidia have been developed and integrated in a photosensitive resin. The individual microlens-waveguide systems of about 8,370 were spherically arranged along the circumference of a polymer dome of 2.5 mm in diameter and each points in different directions. The spherical configuration was realized using a replication process of reconfigurable microtemplates, i.e. the polymer replication using the deformed elastomer membrane with microlens patterns under small pressure (5 kPa ˜ 20 kPa). The characterizations of the small scale microlenses (F/1.8 ˜ F/2.9, DL = 25 mum) and waveguides were also carried out with a modified reflection/transmission confocal microscope. The comparative discussion between natural and artificial compound eyes is described and several future directions based on this work are also proposed.

  14. Microoptical telescope compound eye.

    PubMed

    Duparré, Jacques; Schreiber, Peter; Matthes, André; Pshenay-Severin, Ekaterina; Bräuer, Andreas; Tünnermann, Andreas; Völkel, Reinhard; Eisner, Martin; Scharf, Toralf

    2005-02-01

    A new optical concept for compact digital image acquisition devices with large field of view is developed and proofed experimentally. Archetypes for the imaging system are compound eyes of small insects and the Gabor-Superlens. A paraxial 3x3 matrix formalism is used to describe the telescope arrangement of three microlens arrays with different pitch to find first order parameters of the imaging system. A 2mm thin imaging system with 21x3 channels, 70 masculinex10 masculine field of view and 4.5mm x 0.5mm image size is optimized and analyzed using sequential and non-sequential raytracing and fabricated by microoptics technology. Anamorphic lenses, where the parameters are a function of the considered optical channel, are used to achieve a homogeneous optical performance over the whole field of view. Captured images are presented and compared to simulation results. PMID:19494951

  15. Microoptical telescope compound eye

    NASA Astrophysics Data System (ADS)

    Duparré, Jacques W.; Schreiber, Peter; Matthes, André; Pshenay–Severin, Ekaterina; Bräuer, Andreas; Tünnermann, Andreas; Völkel, Reinhard; Eisner, Martin; Scharf, Toralf

    2005-02-01

    A new optical concept for compact digital image acquisition devices with large field of view is developed and proofed experimentally. Archetypes for the imaging system are compound eyes of small insects and the Gabor Superlens. A paraxial 3x3 matrix formalism is used to describe the telescope arrangement of three microlens arrays with different pitch to find first order parameters of the imaging system. A 2mm thin imaging system with 21x3 channels, 70ºx10º field of view and 4.5mm x 0.5mm image size is optimized and analyzed using sequential and non sequential raytracing and fabricated by microoptics technology. Anamorphic lenses, where the parameters are a function of the considered optical channel, are used to achieve a homogeneous optical performance over the whole field of view. Captured images are presented and compared to simulation results.

  16. Arene complexes of transition metals in reactions with nucleophilic reagents. XVI. Kinetics and mechanism of the reaction of the. pi. -arene complexes of chromium and iron and piperidine

    SciTech Connect

    Oleinik, I.I.; Kun, P.P.; Litvak, V.V.; Shteingarts, V.D.

    1988-05-20

    The kinetics of the reaction of ..pi..-arene complexes of the (/eta/-XC/sub 6/H/sub 4/Cl)ML type (where ML = Cr(CO)/sub 3/ (X = p-Cl), Cr/sup +/(/eta/-C/sub 6/H/sub 5/Cl) (X = H), Fe/sup +/(/eta/-C/sub 5/H/sub 5/) (X = H)) with piperidine in acetone suggest that in the second and third cases the controlling stage is the transformation of the intermediate sigma complex into the reaction products almost entirely by a path with catalysis by the reagent while in the first case it is the formation of the intermediate. The marked increase in the catalytic effect of piperidine in the transition from neutral to cationic ..pi..-arene complexes show that the charge of the metal-complex fragment, coordinated with the arene, has a significant effect on the ratio of the rates of transformation of the intermediate sigma complex into the initial compounds and the final reaction products.

  17. Low-temperature heat capacity of diopside glass (CaMgSi2O6): A calorimetric test of the configurational-entropy theory applied to the viscosity of liquid silicates

    USGS Publications Warehouse

    Richet, P.; Robie, R.A.; Hemingway, B.S.

    1986-01-01

    Heat-capacity measurements have been made between 8 and 370 K on an annealed and a rapidly quenched diopside glass. Between 15 and 200 K, Cp does not depend significantly on the thermal history of the glass. Below 15 K Cp is larger for the quenched than for the annealed specimen. The opposite is true above 200 K as a result of what is interpreted as a secondary relaxation around room temperature. The magnitude of these effects, however, is small enough that the relative entropies S(298)-S(0) of the glasses differ by only 0.5 J/mol K, i.e., a figure within the combined experimental uncertainties. The insensitivity of relative entropies to thermal history supports the assumption that the configurational heat capacity of the liquid may be taken as the heat capacity difference between the liquid and the glass (??Cp). Furthermore, this insensitivity allows calculation of the residual entropies at 0 K of diopside glasses as a function of the fictive temperature from the entropy of fusion of diopside and the heat capacities of the crystalline, glassy and liquid phases. For a glass with a fictive temperature of 1005 K, for example, this calorimetric residual entropy is 24.3 ?? 3 J/mol K, in agreement with the prediction made by RICHET (1984) from an analysis of the viscosity data with the configurational-entropy theory of relaxation processes of Adam and Gibbs (1965). In turn, all the viscosity measurements for liquid diopside, which span the range 0.5-4?? 1013 poise, can be quantitatively reproduced through this theory with the calorimetrically determined entropies and ??Cp data. Finally, the unclear significance of "activation energies" for structural interpretations of viscosity data is emphasized, and the importance of ??Cp and glass-transition temperature systematics for determining the composition and temperature dependences of the viscosity is pointed out. ?? 1986.

  18. Compounded oral ketamine.

    PubMed

    McNulty, Jack P; Hahn, Kristian

    2012-01-01

    The nonnarcotic nonaddictive neuropathic pain reliever ketamine, which was synthesized in the early 1960s by Parke-Davis, was first administered to human patients in 1965. Used by the U. S. military as a field anesthetic during the Vietnam War, it slowly became popular as both an induction and maintenance agent for the general anesthesia required during brief surgical procedures. The use of ketamine in the past has been limited primarily to intravenous administration in hospitalized patients. Very recently, several published reports have described the use of low-dose ketamine for the relief of pain, refractory depression, and anxiety in patients with or without cancer. Because chronic pain, depression, and anxiety often occur in hospice patients with or without cancer and in palliative care patients who are not eligible for hospice, the discovery of new and effective uses for an established drug to treat those conditions has excited interest in the palliative care community. We support that interest with this case report, which describes our experience in treating a 44-year-old male hospice patient with severe constant anxiety, fear, and depression in addition to multiple near-terminal comorbid physical conditions that produce chronic pain. Prior treatments prescribed to resolve this patient's pain, anxiety, and depression had proven ineffective. However, a single low-dose (0.5 mg/kg) subcutaneous test injection of ketamine provided dramatic relief from those symptoms for 80 hours, although the anesthetic effects of that drug are not of long duration. This good outcome has been sustained to date by daily treatment with a compounded flavored oral ketamine solution (40 mg/5 mL) that is not commercially available. Flavoring the solution masks the bitter taste of ketamine and renders the treatment palatable. We found ketamine to be a well-tolerated and effective treatment for the triad of severe anxiety, chronic pain, and severe depression in a hospice patient with multiple comorbid conditions. To our knowledge, this report chronicles the first use of compounded oral ketamine for home-based palliative or hospice care in Louisiana. A formulation for a flavored oral ketamine solution is provided for easy reference. PMID:23072195

  19. Group-IV semiconductor compounds

    SciTech Connect

    Berding, M.A.; Sher, A.; van Schilfgaarde, M.

    1997-08-01

    Properties of ordered group-IV compounds containing carbon, silicon, and germanium are calculated within the local density approximation. Twenty-seven fully relaxed compounds represented by seven different compound structures are compared and, with the exception of SiC, all compounds are found to be metastable. Two trends emerge: carbon-germanium bonds are disfavored, and compounds that have carbon on a common sublattice are the least unbound because of their relatively low strain. When carbon shares a sublattice with silicon or germanium, the large strain results in a narrowing of the band gap, and in some cases the compound is metallic. The most promising structures with the lowest excess energy contain carbon on one sublattice and although they do not lattice match to silicon, they match rather well to silicon carbide. {copyright} {ital 1997} {ital The American Physical Society}

  20. Tunable compound eye cameras

    NASA Astrophysics Data System (ADS)

    Pätz, Daniel; Leopold, Steffen; Knöbber, Fabian; Sinzinger, Stefan; Hoffmann, Martin; Ambacher, Oliver

    2010-05-01

    We present design and realization concepts for thin compound eye cameras with enhanced optical functionality. The systems are based on facets with individually tunable focus lengths and viewing angles for scanning of the object space. The active lens elements are made of aluminum nitride (AlN)/nanocrystalline diamond (NCD) membranes. This material system allows slow thermally actuated elements with a large deformation range as well as fast piezoelectric elements with a smaller deformation range. Due to the extreme mechanical stability of these materials, we are able to realize microoptical components with optimum surface qualities as well as an excellent long-term stability. We use facets of microlenses with 1 mm in diameter and a tunable focusing power to compensate for the focus shift for different viewing angles during the scanning procedure. The beam deflection for scanning is realized either by laterally shifting spherical elements or by a tunable microprism with reduced aberrations. For both actuators we present a design, fabrication concept and first experimental results.

  1. Compound power plant

    SciTech Connect

    Smith, R.R.

    1991-02-05

    This patent describes a compound motor for a vehicle. It comprises: an engine defining therein a chamber for the combustion of fuel, an intake passage leading to the combustion chamber and an exhaust passage leading from the combustion chamber; a drive shaft extending from the engine; means in the engine for rotating the drive shaft in response to the combustion of fuel in the chamber; a rotary compressor at the entry end of the intake passage; a turbine at the exit end of the exhaust passage, the turbine being drivable by exhaust gases from the combustion chamber; means for selectively transferring rotational motion of the turbine to the compressor, the transferring means including a clutch for mechanically connecting or disconnecting the compressor from the turbine; a planetary gear set having a sun gear member, a ring gear member surrounding the sun gear member, a planet gear member rotatable about its own axis and meshed between the sun gear member and the ring gear member, and a planet carrier member upon which the planet gear member is mounted for revolution about the sun gear member; a gear train between one of the members of the planetary gear set and the turbine; another one of the members of the planetary gear set being driven by the shaft extending from the engine; and a final output shaft driven by a third member of the planetary gear set.

  2. Compounding with Silicones.

    PubMed

    Allen, Loyd V

    2015-01-01

    Since the 1940s, methylchlorosilanes have been used to treat glassware to prevent blood from clotting. The use of silicones in pharmaceutical and medical applications has grown to where today they are used in many life-saving devices (pacemakers, hydrocephalic shunts) and pharmaceutical applications from tubing, to excipients in topical formulations, to adhesives to affix transdermal drug delivery systems, and are also being used in products as active pharmaceutical ingredients, such as antiflatulents. About 60% of today's skin-care products now contain some type of silicone where they are considered safe and are known to provide a pleasant "silky-touch," non-greasy, and non-staining feel. Silicones exhibit many useful characteristics, and the safety of these agents supports their numerous applications; their biocompatibility is partially due to their low-chemical reactivity displayed by silicones, low-surface energy, and their hydrophobicity. Silicones are used both as active ingredients and as excipients. In addition is their use for "siliconization," or surface treatment, of many parenteral packaging components. Dimethicone and silicone oil are used as lubricants on stoppers to aid machineability, in syringes to aid piston movement, or on syringe needles to reduce pain upon injection. Silicones are also useful in pharmaceutical compounding as is discussed in this artiele included with this article are in developing formulations with silicones. PMID:26714363

  3. Method of producing cyclohexasilane compounds

    SciTech Connect

    Elangovan, Arumugasamy; Anderson, Kenneth; Boudjouk, Philip R; Schulz, Douglas L

    2015-03-10

    A method of preparing a cyclohexasilane compound from trichlorosilane is provided. The method includes contacting trichlorosilane with a reagent composition to produce a compound containing a tetradecahalocyclohexasilane dianion, such as a tetradecachlorocyclohexasilane dianion. The reagent composition typically includes (a) tertiary polyamine ligand; and (b) a deprotonating reagent, such as a tertiary amine having a pKa of at least about 10.5. Methods of converting the tetradecahalocyclohexasilane dianion-containing compound to cyclohexasilane or a dodecaorganocyclohexasilane are also provided.

  4. Method of preparing metallocene compounds

    DOEpatents

    Rosenblum, Myron; Matchett, Stephen A.

    1992-01-01

    This invention describes a novel method of preparing metallocene compounds. The invention is based on synthesis of novel bis cyclopentadienides that, under appropriate conditions, will either encapsulate a transition metal to produce a metallocene such as ferrocene, or ferrocene derivative, or will yield a polymeric metallocene. Compounds produced by this process are useful as catalysts in propulsion systems, or as anti-knock compounds in gasolines.

  5. Method of preparing metallocene compounds

    SciTech Connect

    Rosenblum, M.; Matchett, S.A.

    1992-06-23

    This invention describes a novel method of preparing metallocene compounds. The invention is based on synthesis of novel bis cyclopentadienides that, under appropriate conditions, will either encapsulate a transition metal to produce a metallocene such as ferrocene, or ferrocene derivative, or will yield a polymeric metallocene. Compounds produced by this process are useful as catalysts in propulsion systems, or as anti-knock compounds in gasolines. 2 figs.

  6. Organic Compounds in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  7. Biomedical Compounds from Marine organisms

    PubMed Central

    Jha, Rajeev Kumar; Zi-rong, Xu

    2004-01-01

    The Ocean, which is called the ‘mother of origin of life’, is also the source of structurally unique natural products that are mainly accumulated in living organisms. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immuno-deficiency syndrome (AIDS), arthritis, etc., while other compounds have been developed as analgesics or to treat inflammation, etc. The life-saving drugs are mainly found abundantly in microorganisms, algae and invertebrates, while they are scarce in vertebrates. Modern technologies have opened vast areas of research for the extraction of biomedical compounds from oceans and seas.

  8. Antimicrobial Compounds in Tears

    PubMed Central

    McDermott, Alison M.

    2013-01-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. PMID:23880529

  9. Bilingual Reading of Compound Words

    ERIC Educational Resources Information Center

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-01-01

    The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English…

  10. ATMOSPHERIC FREONS AND HALOGENATED COMPOUNDS

    EPA Science Inventory

    Ambient levels of atmospheric Freons, halogenated hydrocarbons, and SF6 were measured at various locations in the U.S.A. Compounds such as CCl3F, CCl2F2, CH3-CCl3, and CCl4 were ubiquitious and generally measured at sub ppb levels. Tropospherically reactive compounds such as C2Cl...

  11. Morphological Dynamics in Compound Processing

    ERIC Educational Resources Information Center

    Kuperman, Victor; Bertram, Raymond; Baayen, R. Harald

    2008-01-01

    This paper explores the time-course of morphological processing of trimorphemic Finnish compounds. We find evidence for the parallel access to full-forms and morphological constituents diagnosed by the early effects of compound frequency, as well as early effects of left constituent frequency and family size. We also observe an interaction between

  12. Bilingual Reading of Compound Words

    ERIC Educational Resources Information Center

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-01-01

    The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English

  13. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  14. Assimilation of Unusual Carbon Compounds

    NASA Astrophysics Data System (ADS)

    Middelhoven, Wouter J.

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

  15. Bilayer Effects of Antimalarial Compounds.

    PubMed

    Ramsey, Nicole B; Andersen, Olaf S

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  16. Devices for collecting chemical compounds

    SciTech Connect

    Scott, Jill R; Groenewold, Gary S

    2013-12-24

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  17. Bilayer Effects of Antimalarial Compounds

    PubMed Central

    Ramsey, Nicole B.; Andersen, Olaf S.

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  18. Membrane rejection of nitrogen compounds

    NASA Technical Reports Server (NTRS)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

  19. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1995-08-22

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired. 5 figs.

  20. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, Michael S.

    1995-01-01

    A polishing compound for plastic surfaces. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS.TM., LEXAN.TM., LUCITE.TM., polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  1. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1993-01-01

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains colloidal silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{sup TM}, LEXAN{sup TM}, LUCITE{sup TM}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  2. Regulation of Compound Leaf Development

    PubMed Central

    Wang, Yuan; Chen, Rujin

    2013-01-01

    Leaf morphology is one of the most variable, yet inheritable, traits in the plant kingdom. How plants develop a variety of forms and shapes is a major biological question. Here, we discuss some recent progress in understanding the development of compound or dissected leaves in model species, such as tomato (Solanum lycopersicum), Cardamine hirsuta and Medicago truncatula, with an emphasis on recent discoveries in legumes. We also discuss progress in gene regulations and hormonal actions in compound leaf development. These studies facilitate our understanding of the underlying regulatory mechanisms and put forward a prospective in compound leaf studies. PMID:27135488

  3. Crystallographic properties of fertilizer compounds

    SciTech Connect

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  4. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1991-01-01

    This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

  5. Coumarins, Xanthones and Related Compounds.

    PubMed

    Richomme, Pascal

    2016-01-01

    It has long been known that coumarins (γ-pyrones) and xanthones (α-pyrones) together form a large class of naturally occurring compounds exhibiting a wide range of biological activities.[...]. PMID:26978337

  6. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  7. Compound cuing in free recall.

    PubMed

    Lohnas, Lynn J; Kahana, Michael J

    2014-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity effect should be greater when the 2 most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cuing in both conditional response probabilities and interresponse times. To help rule out a rehearsal-based account of these compound cuing effects, we conducted an experiment with immediate, delayed, and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cuing was present in all conditions, and was not significantly influenced by the presence of interitem distractors. PMID:23957364

  8. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, Amy A. (Augusta, GA)

    1996-01-01

    A method for making a composition for measuring the concentration of chloated aromatic compounds in aqueous fluids, and an optical probe for use with the method. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis.

  9. Biologically inspired artificial compound eyes.

    PubMed

    Jeong, Ki-Hun; Kim, Jaeyoun; Lee, Luke P

    2006-04-28

    This work presents the fabrication of biologically inspired artificial compound eyes. The artificial ommatidium, like that of an insect's compound eyes, consists of a refractive polymer microlens, a light-guiding polymer cone, and a self-aligned waveguide to collect light with a small angular acceptance. The ommatidia are omnidirectionally arranged along a hemispherical polymer dome such that they provide a wide field of view similar to that of a natural compound eye. The spherical configuration of the microlenses is accomplished by reconfigurable microtemplating, that is, polymer replication using the deformed elastomer membrane with microlens patterns. The formation of polymer waveguides self-aligned with microlenses is also realized by a self-writing process in a photosensitive polymer resin. The angular acceptance is directly measured by three-dimensional optical sectioning with a confocal microscope, and the detailed optical characteristics are studied in comparison with a natural compound eye. PMID:16645090

  10. Photochemical dimerization of organic compounds

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.; Muedas, Cesar A.; Ferguson, Richard R.

    1992-01-01

    At least one of selectivity and reaction rate of photosensitized vapor phase dimerizations, including dehydrodimerizations, hydrodimerizations and cross-dimerizations of saturated and unsaturated organic compounds is improved by conducting the dimerization in the presence of hydrogen or nitrous oxide.

  11. Aza compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.Q.; McBreen, J.

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li{sup +} ion in alkali metal batteries. 3 figs.

  12. Aza compounds as anion receptors

    DOEpatents

    Lee, Hung Sui; Yang, Xiao-Qing; McBreen, James

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li.sup.+ ion in alkali metal batteries.

  13. Sensing acetylcholine and anticholinesterase compounds.

    PubMed

    Schena, Alberto; Johnsson, Kai

    2014-01-27

    Acetylcholine is a key neurotransmitter, and anticholinesterase agents are essential compounds used as medical drugs, pesticides, and chemical warfare agents. A semisynthetic fluorescence-based probe for the direct, real-time detection of acetylcholine and anticholinesterase compounds is introduced. The probe possesses good sensitivity, tunable detection range, and can be selectively targeted to cell surfaces, thereby making it an attractive tool for applications in analytical chemistry and quantitative biology. PMID:24339043

  14. Miniature curved artificial compound eyes

    PubMed Central

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L’Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A.; Franceschini, Nicolas

    2013-01-01

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

  15. Miniature curved artificial compound eyes.

    PubMed

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-01

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

  16. Physical properties of glycosyl diacylglycerols. 1. Calorimetric studies of a homologous series of 1,2-di-O-acyl-3-O-(. alpha. -D-glucopyranosyl)-sn-glycerols

    SciTech Connect

    Mannock, D.A.; Lewis, R.N.A.H.; McElhaney, R.N. )

    1990-08-28

    The polymorphic phase behavior of aqueous dispersions of a homologous series of 1,2-di-O-acyl-3-O-({alpha}-D-glucopyranosyl)-sn-glycerols was studied by differential scanning calorimetry. At fast heating rates unannealed samples of these lipids exhibit a strongly energetic transition, which has been identified as a lamellar gel/liquid crystalline (L{sub {beta}}/L{sub {alpha}}) phase transition (short- and medium-chain compounds) or a lamellar gel to inverted hexagonal (L{sub {beta}}/H{sub II}) phase transition (long-chain compounds) by x-ray diffraction studies. At still higher temperatures, some of the lipids that form lamellar liquid-crystalline phases exhibit an additional transition, which has been identified as a transition to an inverted nonbilayer phase by x-ray diffraction studies. The lamellar gel phase formed on initial cooling of these lipids is a metastable structure, which, when annealed under appropriate conditions, transforms to a more stable lamellar gel phase, which has been identified as a poorly hydrated crystal-like phase with tilted acyl chains by x-ray diffraction measurements. These results indicate that the length of the acyl chain affects both the kinetic and thermodynamic properties of the crystalline phases of these lipids as well as the type of nonbilayer phase that they form. Moreover, when compared with the {beta}-anomers, these {alpha}-D-glucosyl diacylglycerols are more prone to form ordered crystalline gel phases at low temperatures and are somewhat less prone to form nonbilayer phases at elevated temperatures. The authors suggest that this is, in part, due to a change in orientation of the glucopyranosyl ring relative to the bilayer surface, which in turn affects the way(s) in which the sugar headgroups interact with each other and with water.

  17. Kinetics of a bioactive compound (caffeine) mobility at the vicinity of the mechanical glass transition temperature induced by gelling polysaccharide.

    PubMed

    Jiang, Bin; Kasapis, Stefan

    2011-11-01

    An investigation of the diffusional mobility of a bioactive compound (caffeine) within the high-solid (80.0% w/w) matrices of glucose syrup and κ-carrageenan plus glucose syrup exhibiting distinct mechanical glass transition properties is reported. The experimental temperature range was from 20 to -60 °C, and the techniques of modulated differential scanning calorimetry, small deformation dynamic oscillation in shear, and UV spectrometry were employed. Calorimetric and mechanical measurements were complementary in recording the relaxation dynamics of high-solid matrices upon controlled heating. Predictions of the reaction rate theory and the combined WLF/free volume framework were further utilized to pinpoint the glass transition temperature (T(g)) of the two matrices in the softening dispersion. Independent of composition, calorimetry yielded similar T(g) predictions for both matrices at this level of solids. Mechanical experimentation, however, was able to detect the effect of adding gelling polysaccharide to glucose syrup as an accelerated pattern of vitrification leading to a higher value of T(g). Kinetic rates of caffeine diffusion within the experimental temperature range were taken with UV spectroscopy. These demonstrated the pronounced effect of the gelling κ-carrageenan/glucose syrup mixture to retard diffusion of the bioactive compound near the mechanical T(g). Modeling of the diffusional mobility of caffeine produced activation energy and fractional free-volume estimates, which were distinct from those of the carbohydrate matrix within the glass transition region. This result emphasizes the importance of molecular interactions between macromolecular matrix and small bioactive compound in glass-related relaxation phenomena. PMID:21936521

  18. Photoprotective compounds from marine organisms.

    PubMed

    Rastogi, Rajesh P; Richa; Sinha, Rajeshwar P; Singh, Shailendra P; Häder, Donat-P

    2010-06-01

    The substantial loss in the stratospheric ozone layer and consequent increase in solar ultraviolet radiation on the earth's surface have augmented the interest in searching for natural photoprotective compounds in organisms of marine as well as freshwater ecosystems. A number of photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin, carotenoids and several other UV-absorbing substances of unknown chemical structure have been identified from different organisms. MAAs form the most common class of UV-absorbing compounds known to occur widely in various marine organisms; however, several compounds having UV-screening properties still need to be identified. The synthesis of scytonemin, a predominant UV-A-photoprotective pigment, is exclusively reported in cyanobacteria. Carotenoids are important components of the photosynthetic apparatus that serve both light-harvesting and photoprotective functions, either by direct quenching of the singlet oxygen or other toxic reactive oxygen species or by dissipating the excess energy in the photosynthetic apparatus. The production of photoprotective compounds is affected by several environmental factors such as different wavelengths of UVR, desiccation, nutrients, salt concentration, light as well as dark period, and still there is controversy about the biosynthesis of various photoprotective compounds. Recent studies have focused on marine organisms as a source of natural bioactive molecules having a photoprotective role, their biosynthesis and commercial application. However, there is a need for extensive work to explore the photoprotective role of various UV-absorbing compounds from marine habitats so that a range of biotechnological and pharmaceutical applications can be found. PMID:20401734

  19. Method for purifying bidentate organophosphorus compounds

    DOEpatents

    Schulz, Wallace W.

    1977-01-01

    Bidentate organophosphorus compounds useful for extracting actinide elements from acidic nuclear waste solutions are purified of undesirable acidic impurities by contacting the compounds with ethylene glycol which preferentially extracts the impurities found in technical grade bidentate compounds.

  20. Host compounds for red phosphorescent OLEDs

    DOEpatents

    Xia, Chuanjun; Cheon, Kwang -Ohk

    2015-08-25

    Novel compounds containing a triphenylene moiety linked to an .alpha..beta. connected binaphthyl ring system are provided. These compounds have surprisingly good solubility in organic solvents and are useful as host compounds in red phosphorescent OLEDs.

  1. Planck 2013 results. XVI. Cosmological parameters

    NASA Astrophysics Data System (ADS)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J. J.; Bonaldi, A.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Bridges, M.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cappellini, B.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chary, R.-R.; Chen, X.; Chiang, H. C.; Chiang, L.-Y.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J.-M.; Désert, F.-X.; Dickinson, C.; Diego, J. M.; Dolag, K.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Gaier, T. C.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giardino, G.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Haissinski, J.; Hamann, J.; Hansen, F. K.; Hanson, D.; Harrison, D.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hou, Z.; Hovest, W.; Huffenberger, K. M.; Jaffe, A. H.; Jaffe, T. R.; Jewell, J.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Laureijs, R. J.; Lawrence, C. R.; Leach, S.; Leahy, J. P.; Leonardi, R.; León-Tavares, J.; Lesgourgues, J.; Lewis, A.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maffei, B.; Maino, D.; Mandolesi, N.; Maris, M.; Marshall, D. J.; Martin, P. G.; Martínez-González, E.; Masi, S.; Massardi, M.; Matarrese, S.; Matthai, F.; Mazzotta, P.; Meinhold, P. R.; Melchiorri, A.; Melin, J.-B.; Mendes, L.; Menegoni, E.; Mennella, A.; Migliaccio, M.; Millea, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; O'Dwyer, I. J.; Osborne, S.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Partridge, B.; Pasian, F.; Patanchon, G.; Pearson, D.; Pearson, T. J.; Peiris, H. V.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Platania, P.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Starck, J.-L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sureau, F.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Tavagnacco, D.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Türler, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, M.; White, S. D. M.; Wilkinson, A.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-11-01

    This paper presents the first cosmological results based on Planck measurements of the cosmic microwave background (CMB) temperature and lensing-potential power spectra. We find that the Planck spectra at high multipoles (ℓ ≳ 40) are extremely well described by the standard spatially-flat six-parameter ΛCDM cosmology with a power-law spectrum of adiabatic scalar perturbations. Within the context of this cosmology, the Planck data determine the cosmological parameters to high precision: the angular size of the sound horizon at recombination, the physical densities of baryons and cold dark matter, and the scalar spectral index are estimated to be θ∗ = (1.04147 ± 0.00062) × 10-2, Ωbh2 = 0.02205 ± 0.00028, Ωch2 = 0.1199 ± 0.0027, and ns = 0.9603 ± 0.0073, respectively(note that in this abstract we quote 68% errors on measured parameters and 95% upper limits on other parameters). For this cosmology, we find a low value of the Hubble constant, H0 = (67.3 ± 1.2) km s-1 Mpc-1, and a high value of the matter density parameter, Ωm = 0.315 ± 0.017. These values are in tension with recent direct measurements of H0 and the magnitude-redshift relation for Type Ia supernovae, but are in excellent agreement with geometrical constraints from baryon acoustic oscillation (BAO) surveys. Including curvature, we find that the Universe is consistent with spatial flatness to percent level precision using Planck CMB data alone. We use high-resolution CMB data together with Planck to provide greater control on extragalactic foreground components in an investigation of extensions to the six-parameter ΛCDM model. We present selected results from a large grid of cosmological models, using a range of additional astrophysical data sets in addition to Planck and high-resolution CMB data. None of these models are favoured over the standard six-parameter ΛCDM cosmology. The deviation of the scalar spectral index from unity isinsensitive to the addition of tensor modes and to changes in the matter content of the Universe. We find an upper limit of r0.002< 0.11 on the tensor-to-scalar ratio. There is no evidence for additional neutrino-like relativistic particles beyond the three families of neutrinos in the standard model. Using BAO and CMB data, we find Neff = 3.30 ± 0.27 for the effective number of relativistic degrees of freedom, and an upper limit of 0.23 eV for the sum of neutrino masses. Our results are in excellent agreement with big bang nucleosynthesis and the standard value of Neff = 3.046. We find no evidence for dynamical dark energy; using BAO and CMB data, the dark energy equation of state parameter is constrained to be w = -1.13-0.10+0.13. We also use the Planck data to set limits on a possible variation of the fine-structure constant, dark matter annihilation and primordial magnetic fields. Despite the success of the six-parameter ΛCDM model in describing the Planck data at high multipoles, we note that this cosmology does not provide a good fit to the temperature power spectrum at low multipoles. The unusual shape of the spectrum in the multipole range 20 ≲ ℓ ≲ 40 was seen previously in the WMAP data and is a real feature of the primordial CMB anisotropies. The poor fit to the spectrum at low multipoles is not of decisive significance, but is an "anomaly" in an otherwise self-consistent analysis of the Planck temperature data.

  2. Physical properties of glycosyl diacylglycerols. 1. Calorimetric studies of a homologous series of 1,2-di-O-acyl-3-O-(alpha-D-glucopyranosyl)-sn-glycerols.

    PubMed

    Mannock, D A; Lewis, R N; McElhaney, R N

    1990-08-28

    The polymorphic phase behavior of aqueous dispersions of a homologous series of 1,2-di-O-acyl-3-O-(alpha-D-glucopyranosyl)-sn-glycerols was studied by differential scanning calorimetry. At fast heating rates unannealed samples of these lipids exhibit a strongly energetic transition, which has been identified as a lamellar gel/liquid crystalline (L beta/L alpha) phase transition (short- and medium-chain compounds) or a lamellar gel to inverted hexagonal (L beta/HII) phase transition (long-chain compounds) by X-ray diffraction studies (Sen et al., 1990). At still higher temperatures, some of the lipids that form lamellar liquid-crystalline phases exhibit an additional transition, which has been identified as a transition to an inverted nonbilayer phase by X-ray diffraction studies. The lamellar gel phase formed on initial cooling of these lipids is a metastable structure, which, when annealed under appropriate conditions, transforms to a more stable lamellar gel phase, which has been identified as a poorly hydrated crystal-like phase with tilted acyl chains by X-ray diffraction measurements (Sen et al., 1990). With the exception of the di-19:0 homologue, the crystalline phases of these lipids are stable to temperatures higher than those at which their L beta phases melt and, as a result, they convert directly to L alpha or HII phases on heating. Our results indicate that the length of the acyl chain affects both the kinetic and thermodynamic properties of the crystalline phases of these lipids as well as the type of nonbilayer phase that they form. Moreover, when compared with the beta-anomers, these alpha-D-glucosyl diacylglycerols are more prone to form ordered crystalline gel phases at low temperatures and are somewhat less prone to form nonbilayer phases at elevated temperatures. Thus the physical properties of glucolipids (and possibly all glycolipids) are very sensitive to the nature of the anomeric linkage between the sugar headgroup and the glycerol backbone of the lipid molecule. We suggest that this is, in part, due to a change in orientation of the glucopyranosyl ring relative to the bilayer surface, which in turn affects the way(s) in which the sugar headgroups interact with each other and with water. PMID:2261435

  3. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  4. Antitumor compounds from marine actinomycetes.

    PubMed

    Olano, Carlos; Mndez, Carmen; Salas, Jos A

    2009-01-01

    Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds. PMID:19597582

  5. Antitumor Compounds from Marine Actinomycetes

    PubMed Central

    Olano, Carlos; Méndez, Carmen; Salas, José A.

    2009-01-01

    Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds. PMID:19597582

  6. Microbial Identification in Pharmaceutical Compounding.

    PubMed

    Hyde, Tiffany; Anstead, James; Schade, Lisa; Zellner, James

    2016-01-01

    Compounding pharmacies and contract testing laboratories can readily utilize critical information that microbial identification methods provide. Rapidly identifying the genus and species of environmental isolates and sample contaminates provides pharmacies and laboratories the opportunity to determine the possible source and implement corrective actions to improve compounding and testing processes. The microbial identification data collected from a compounding environment is critical. It is important to have accurate and specific microbial information to guide environmental collection practices, validation studies, and troubleshooting initiatives. The different technologies available provide varying levels of identification. They range from phenotypic assays to more accurate molecular-based techniques, including macromolecular methods and whole genome sequencing. Selecting the appropriate identification methodology requires evaluating multiple factors including the level of information required (genus only, genus and species, etc.) and the pharmacy's tolerance for unidentified or incorrectly identified isolates. PMID:27125052

  7. Biodegradation of halogenated organic compounds.

    PubMed Central

    Chaudhry, G R; Chapalamadugu, S

    1991-01-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant compounds. Recent developments in designing recombinant microorganisms and hybrid metabolic pathways are discussed. PMID:2030673

  8. Biodegradation of halogenated organic compounds.

    PubMed

    Chaudhry, G R; Chapalamadugu, S

    1991-03-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant compounds. Recent developments in designing recombinant microorganisms and hybrid metabolic pathways are discussed. PMID:2030673

  9. Hydrophobic Compounds Reshape Membrane Domains

    PubMed Central

    Barnoud, Jonathan; Rossi, Giulia; Marrink, Siewert J.; Monticelli, Luca

    2014-01-01

    Cell membranes have a complex lateral organization featuring domains with distinct composition, also known as rafts, which play an essential role in cellular processes such as signal transduction and protein trafficking. In vivo, perturbations of membrane domains (e.g., by drugs or lipophilic compounds) have major effects on the activity of raft-associated proteins and on signaling pathways, but they are difficult to characterize because of the small size of the domains, typically below optical resolution. Model membranes, instead, can show macroscopic phase separation between liquid-ordered and liquid-disordered domains, and they are often used to investigate the driving forces of membrane lateral organization. Studies in model membranes have shown that some lipophilic compounds perturb membrane domains, but it is not clear which chemical and physical properties determine domain perturbation. The mechanisms of domain stabilization and destabilization are also unknown. Here we describe the effect of six simple hydrophobic compounds on the lateral organization of phase-separated model membranes consisting of saturated and unsaturated phospholipids and cholesterol. Using molecular simulations, we identify two groups of molecules with distinct behavior: aliphatic compounds promote lipid mixing by distributing at the interface between liquid-ordered and liquid-disordered domains; aromatic compounds, instead, stabilize phase separation by partitioning into liquid-disordered domains and excluding cholesterol from the disordered domains. We predict that relatively small concentrations of hydrophobic species can have a broad impact on domain stability in model systems, which suggests possible mechanisms of action for hydrophobic compounds in vivo. PMID:25299598

  10. Magnetic properties and magnetocaloric effect in Ho{sub 6-x}Er{sub x}MnBi{sub 2} compounds

    SciTech Connect

    Wang Fang; Yuan Fengying; Cao Yang; Gao Chunjing; Hao Yanming; Zhang Jian; Shen Jun; Sun Jirong; Shen Baogen

    2010-05-15

    Magnetic properties and magnetocaloric effect of compounds Ho{sub 6-x}Er{sub x}MnBi{sub 2} (x=0,3,6) are investigated experimentally. All the compounds crystallize in the hexagonal Zr{sub 6}CoAs{sub 2}-type structure and show a sharp drop in the magnetization around their respective magnetic ordering temperature, which is 201 K (x=0), 147 K (x=3), and 98 K (x=6), respectively. Either thermal or magnetic hysteresis around the phase transition is not observed, suggesting a second order phase transition nature. The magnetic entropy change ({Delta}S{sub m}) calculated from the Maxwell relation using the collected magnetization data is 10.6 (x=6), 7.3 (x=3), and 5.0 J kg{sup -1} K{sup -1} (x=0), respectively. The shape of the {Delta}S{sub m}-T curve has a good symmetry below and above the magnetic ordering temperature, and the value of the magnetic entropy change increases monotonously with increasing field change. The calorimetric technique has also been used for Er{sub 6}MnBi{sub 2} to check the credibility of the magnetic method.

  11. Persulfate Oxidation of Gasoline Compounds

    NASA Astrophysics Data System (ADS)

    Sra, K.; Thomson, N.; Barker, J.

    2009-05-01

    In situ chemical oxidation (ISCO) using persulfate is a promising remediation technology that can be potentially applied to a wide range of organic contaminants. Gasoline compounds are of particular interest because they extensively impact the soil and groundwater, and are highly persistent and toxic. In this investigation, destruction of specific gasoline compounds (benzene, toluene, ethylbenzenes, xylenes, trimethylbenzenes (TMBs) and naphthalene), and fractions (F1 and F2) by activated and inactivated persulfate was studied at the bench-scale. Aqueous phase batch reactors (25 mL) for inactivated systems employed persulfate at two concentrations (1 or 20 g/L), and activated systems were conducted with a persulfate concentration of 20 g/L. In the activated systems, the ability of hydrogen peroxide or chelated-ferrous as an activator was examined at two experimental conditions (peroxide molar ratio 0.1 and 1.0 with respect to persulfate; and citric acid chelated ferrous at 150 and 600 mg/L). All treatments and controls contained an initial gasoline concentration of approximately 25 mg/L and were run in triplicate. Sampling for gasoline compounds was conducted over <28 day reaction period. The controls showed insignificant degradation for all the gasoline compounds and fractions examined while inactivated persulfate at 1 g/L showed little (<10%) decrease in the concentration of gasoline compounds over the 28 day reaction period. Inactivated persulfate at 20 g/L demonstrated a significant decrease in the aqueous concentration of BTEX (>99%), TMB (>94%) and naphthalene (>71%). Oxidation of the F1 fraction (>94%) was more pronounced than the F2 fraction (>80%), and >93% TPH was oxidized. Use of peroxide as an activator at a molar ratio of 0.1 improved the destruction of TMBs (>99%) and naphthalene (>85%) while maintaining the high removal of BTEX (>99%) compounds. Increase in activator strength (molar ratio 1.0) decreased the destruction of xylenes (>86%) and TMBs (>81%). The decrease in concentration of all the compounds was higher for a molar ratio of 1.0 (<27%) as compared with a molar ratio of 0.1 (<11%). The activation by ferrous concentration resulted in higher oxidation of compounds (except naphthalene) as compared with unactivated or peroxide activated persulfate. 1,3,5-TMB was completed oxidized after 4 days using higher chelated ferrous concentration and after 12 days using lower chelated ferrous concentration for persulfate activation. In general, increase in chelated ferrous concentration resulted in higher oxidation of the gasoline compounds. While oxidation of F1 fraction was similar for two ferrous activation conditions, the oxidation of F2 fraction was lower when ferrous activation at 600 mg/L was employed. Use of persulfate at high dosages by itself or in combination with higher doses of chelated ferrous or optimum doses of peroxide as an activator seems to be a viable option for remediation of gasoline compounds examined in this study. Persulfate appears to be particularly effective in the oxidation of BTEX compounds, but may require ferrous activation for a complete oxidation of TMBs and peroxide activation for oxidation of naphthalene.

  12. Structural, functional and calorimetric investigation of MosA, a dihydrodipicolinate synthase from Sinorhizobium meliloti l5-30, does not support involvement in rhizopine biosynthesis.

    PubMed

    Phenix, Christopher P; Nienaber, Kurt; Tam, Pui Hang; Delbaere, Louis T J; Palmer, David R J

    2008-07-01

    MosA is an enzyme from Sinorhizobium meliloti L5-30, a beneficial soil bacterium that forms a symbiotic relationship with leguminous plants. MosA was proposed to catalyze the conversion of scyllo-inosamine to 3-O-methyl-scyllo-inosamine (compounds known as rhizopines), despite the MosA sequence showing a strong resemblance to dihydrodipicolinate synthase (DHDPS) sequences rather than to methyltransferases. Our laboratory has already shown that MosA is an efficient catalyst of the DHDPS reaction. Here we report the structure of MosA, solved to 1.95 A resolution, which resembles previously reported DHDPS structures. In this structure Lys161 forms a Schiff base adduct with pyruvate, consistent with the DHDPS mechanism. We have synthesized both known rhizopines and investigated their ability to interact with MosA in the presence and absence of methyl donors. No MosA-catalyzed methyltransferase activity is observed in the presence of scyllo-inosamine and S-adenosylmethionine (SAM). 2-Oxobutyrate can form a Schiff base with MosA, acting as a competitive inhibitor of MosA-catalyzed dihydrodipicolinate synthesis. It can be trapped on the enzyme by reaction with sodium borohydride, but does not act as a methyl donor. The presence of rhizopines does not affect the kinetics of dihydrodipicolinate synthesis. Isothermal titration calorimetry (ITC) shows no apparent interaction of MosA with rhizopines and SAM. Similar experiments with pyruvate as titrant demonstrate that the reversible Schiff base formation is largely entropically driven. This is the first use of ITC to study Schiff base formation between an enzyme and its substrate. PMID:18536061

  13. Role of an invariant lysine residue in folate binding on Escherichia coli thymidylate synthase: calorimetric and crystallographic analysis of the K48Q mutant

    PubMed Central

    Arvizu-Flores, Aldo A.; Sugich-Miranda, Rocio; Arreola, Rodrigo; Garcia-Orozco, Karina D.; Velazquez-Contreras, Enrique F.; Montfort, William R.; Maley, Frank; Sotelo-Mundo, Rogerio R.

    2008-01-01

    Thymidylate synthase (TS) catalyzes the reductive methylation of deoxyuridine monophosphate (dUMP) using methylene tetrahydrofolate (CH2THF) as cofactor, the glutamate tail of which forms a water-mediated hydrogen-bond with an invariant lysine residue of this enzyme. To understand the role of this interaction, we studied the K48Q mutant of Escherichia coli TS using structural and biophysical methods. The kcat of the K48Q mutant was 430 fold lower than wild-type TS in activity, while the the Km for the (R)-stereoisomer of CH2THF was 300 M, about 30 fold larger than Km from the wild-type TS. Affinity constants were determined using isothermal titration calorimetry, which showed that binding was reduced by one order of magnitude for folate-like TS inhibitors, such as propargyl-dideaza folate (PDDF) or compounds that distort the TS active site like BW1843U89 (U89). The crystal structure of the K48Q-dUMP complex revealed that dUMP binding is not impaired in the mutamt, and that U89 in a ternary complex of K48Q-nucleotide-U89 was bound in the active site with subtle differences relative to comparable wild type complexes. PDDF failed to form ternary complexes with K48Q and dUMP. Thermodynamic data correlated with the structural determinations, since PDDF binding was dominated by enthalpic effects while U89 had an important entropic component. In conclusion, K48 is critical for catalysis since it leads to a productive CH2THF binding, while mutation at this residue does not affect much the binding of inhibitors that do not make contact with this group. PMID:18403248

  14. Calorimetric studies of the interaction between the insulin-enhancing drug candidate bis(maltolato)oxovanadium(IV) (BMOV) and human serum apo-transferrin.

    PubMed

    Bordbar, Abdol-Khalegh; Creagh, A Louise; Mohammadi, Fakhrossadat; Haynes, Charles A; Orvig, Chris

    2009-04-01

    Bis(maltolato)oxovanadium(IV) (BMOV), and its ethylmaltol analog, bis(ethylmaltolato)oxovanadium(IV) (BEOV), are candidate insulin-enhancing agents for the treatment of type 2 diabetes mellitus; in mid-2008, BEOV advanced to phase II clinical testing. The interactions of BMOV and its inorganic congener, vanadyl sulfate (VOSO(4)), with human serum apo-transferrin (hTf) were investigated using differential scanning calorimetry (DSC). Addition of BMOV or VOSO(4) to apo-hTf resulted in an increase in thermal stability of both the C- and N-lobes of transferrin as a result of binding to either vanadyl compound. A series of DSC thermograms of hTf solutions containing different molar ratios of BMOV and VOSO(4) were used to determine binding constants; at 25 degrees C the binding constants of BMOV to the C- and N-lobes of apo-hTf were found to be 3 (+/-1)x10(5) and 1.8 (+/-0.7)x10(5)M(-1), respectively. The corresponding values for VOSO(4) were 1.7 (+/-0.3)x10(5) and 7 (+/-2)x10(4)M(-1). The results show that the vanadium species initially presented as either BMOV or VOSO(4) had similar affinities for human serum transferrin due to oxidation of solvated vanadyl(IV) prior to complexation to transferrin. Binding of metavanadate (VO(3)(-)) was confirmed by DSC and isothermal titration calorimetry (ITC) experiments of the interaction between sodium metavanadate (NaVO(3)) and hTf. PMID:19056126

  15. Compound Cuing in Free Recall

    ERIC Educational Resources Information Center

    Lohnas, Lynn J.; Kahana, Michael J.

    2014-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity

  16. Cryogenic container compound suspension strap

    NASA Technical Reports Server (NTRS)

    Vorreiter, J. W. (Inventor)

    1980-01-01

    A support strap for use in a cryogenic storage vessel for supporting the inner shell from the outer shell with a minimum heat leak is presented. The compound suspension strap is made from a unidirectional fiberglass epoxy composite material with an ultimate tensile strength and fatigue strength which are approximately doubled when the material is cooled to a cryogenic temperature.

  17. Infrared Spectroscopy of Deuterated Compounds.

    ERIC Educational Resources Information Center

    MacCarthy, Patrick

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment (based on the potassium bromide pressed-pellet method) involving the infrared spectroscopy of deuterated compounds. Deuteration refers to deuterium-hydrogen exchange at active hydrogen sites in the molecule. (JN)

  18. Instability of viscoelastic compound jets

    NASA Astrophysics Data System (ADS)

    Ye, Han-Yu; Yang, Li-Jun; Fu, Qing-Fei

    2016-04-01

    This paper investigates the axisymmetric instability of a viscoelastic compound jet, for which the constitutive relation is described by the Oldroyd B model. It is found that a viscoelastic compound jet is more unstable than a Newtonian compound jet, regardless of whether the viscoelastic compound jet is inner-Newtonian-outer-viscoelastic, inner-viscoelastic-outer-Newtonian, or fully viscoelastic. It is also found that an increase in the stress relaxation time of the inner or outer fluid renders the jet more unstable, while an increase in the time constant ratio makes the jet less unstable. An analysis of the energy budget of the destabilization process is performed, in which a formulation using the relative rate of change of energy is adopted. The formulation is observed to provide a quantitative analysis of the contribution of each physical factor (e.g., release of surface energy and viscous dissipation) to the temporal growth rate. The energy analysis reveals the mechanisms of various trends in the temporal growth rate, including not only how the growth rate changes with the parameters, but also how the growth rate changes with the wavenumber. The phenomenon of the dispersion relation presenting two local maxima, which occurred in previous research, is explained by the present energy analysis.

  19. Students' Categorizations of Organic Compounds

    ERIC Educational Resources Information Center

    Domin, Daniel S.; Al-Masum, Mohammad; Mensah, John

    2008-01-01

    Categorization is a fundamental psychological ability necessary for problem solving and many other higher-level cognitive tasks. In organic chemistry, students must establish groupings of different chemical compounds in order not only to solve problems, but also to understand course content. Classic models of categorization emphasize similarity as…

  20. Absorption of different lead compounds

    PubMed Central

    Barltrop, D.; Meek, F.

    1975-01-01

    A rapid method for the determination of relative absorption of dietary lead by rats is described. The influence of age, weight and dose rate has been determined and using standard conditions the tissue lead content of blood, kidney and femur are significantly correlated with each other and are a function of ingested lead. Eight lead compounds were evaluated using this technique and the findings related to lead acetate as a reference compound. Of the inorganic preparations studied, lead carbonate (basic) and metallic lead showed a twelve-fold difference in absorption, with the remaining compounds giving intermediate values. The absorption of lead from four organic compounds was determined from diets containing 7·5% corn oil added to the standard diet. Lead tallate was absorbed to the same degree as lead acetate, but lesser absorptions resulted from lead octoate, naphthenate and alsynate. The addition of corn oil to a final concentration of 7·5% of the diet enhanced the absorption of lead acetate. PMID:1208290

  1. Halogenated Compounds from Marine Algae

    PubMed Central

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-01-01

    Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

  2. Students' Categorizations of Organic Compounds

    ERIC Educational Resources Information Center

    Domin, Daniel S.; Al-Masum, Mohammad; Mensah, John

    2008-01-01

    Categorization is a fundamental psychological ability necessary for problem solving and many other higher-level cognitive tasks. In organic chemistry, students must establish groupings of different chemical compounds in order not only to solve problems, but also to understand course content. Classic models of categorization emphasize similarity as

  3. Compound Cuing in Free Recall

    ERIC Educational Resources Information Center

    Lohnas, Lynn J.; Kahana, Michael J.

    2014-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity…

  4. Cerium Oxide and Cerium Compounds

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 08 / 002F www.epa.gov / iris TOXICOLOGICAL REVIEW OF Cerium Oxide and Cerium Compounds ( CAS No . 1306 - 38 - 3 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) September 2009 U.S . Environmental Protection Agency Washington , DC ii DISCLAIMER Th

  5. Large Constituent Families Help Children Parse Compounds

    ERIC Educational Resources Information Center

    Krott, Andrea; Nicoladis, Elena

    2005-01-01

    The family size of the constituents of compound words, or the number of compounds sharing the constituents, has been shown to affect adults' access to compound words in the mental lexicon. The present study was designed to see if family size would affect children's segmentation of compounds. Twenty-five English-speaking children between 3;7 and…

  6. Large Constituent Families Help Children Parse Compounds

    ERIC Educational Resources Information Center

    Krott, Andrea; Nicoladis, Elena

    2005-01-01

    The family size of the constituents of compound words, or the number of compounds sharing the constituents, has been shown to affect adults' access to compound words in the mental lexicon. The present study was designed to see if family size would affect children's segmentation of compounds. Twenty-five English-speaking children between 3;7 and

  7. Calorimetric, spectroscopic and structural investigations of phase polymorphism in [Ru(NH3)6](BF4)3. Part I

    NASA Astrophysics Data System (ADS)

    Dołęga, Diana; Mikuli, Edward; Inaba, Akira; Górska, Natalia; Hołderna-Natkaniec, Krystyna; Nitek, Wojciech

    2013-01-01

    Four crystalline phases of the coordination compound [Ru(NH3)6](BF4)3 are identified by adiabatic calorimetry. Three phase transitions, one at TC3(IV→III)=30.7 K, the second at TC2(III→II)=91.7 K (both accompanied by comparable entropy changes 3.0 and 3.1 J K-1 mol-1, respectively) and the third at TC1(II→I)=241.6 K (accompanied by an entropy change of 8.1 J K-1 mol-1) were discovered. X-ray single crystal diffraction (at 293 K) demonstrates that phase I is a highly dynamic disordered cubic phase (Fm3¯m, No. 225) with two types of BF4- anions differing in a degree of disorder. In phase II (at 170 K) the structure remains cubic (Ia3¯, No. 206), with two different types of cations and four different types of anions. Splitting of certain IR bands connected with NH3 ligands at the observed phase transitions suggests a lowering of the symmetry of the [Ru(NH3)6]3+ complex cation. Both NH3 ligands and BF4- anions perform fast reorientations (τR≈10-12 s), which are significantly slowed down below the phase transition at TC3. 1H NMR studies led to estimate the values of the activation energy of NH3 ligands reorientation in the phases II and I as equal to ˜8 kJ mol-1. In phase I the whole hexammineruthenium(III) cations reorientation as a tumbling process can be noticed. The activation energy value of this motion is ˜24 kJ mol-1. 19F NMR studies give the values of the activation energy of BF4- anions reorientation as ˜6 kJ mol-1. Above the phase transition temperature half of BF4- anions perform a tumbling motion with Ea≈8 kJ mol-1.

  8. The nature of compounds: a psychocentric perspective.

    PubMed

    Libben, Gary

    2014-01-01

    Although compound words often seem to be words that themselves contain words, this paper argues that this is not the case for the vast majority of lexicalized compounds. Rather, it is claimed that as a result of acts of lexical processing, the constituents of compound words develop into new lexical representations. These representations are bound to specific morphological roles and positions (e.g., head, modifier) within a compound word. The development of these positionally bound compound constituents creates a rich network of lexical knowledge that facilitates compound processing and also creates some of the well-documented patterns in the psycholinguistic and neurolinguistic study of compounding. PMID:24580553

  9. Olive oil phenolic compounds affect the release of aroma compounds.

    PubMed

    Genovese, Alessandro; Caporaso, Nicola; Villani, Veronica; Paduano, Antonello; Sacchi, Raffaele

    2015-08-15

    Twelve aroma compounds were monitored and quantified by dynamic headspace analysis after their addition in refined olive oil model systems with extra virgin olive oil (EVOO) biophenols to simulate EVOO aroma. The influence of polyphenols on aroma release was studied under simulated mouth conditions by using human saliva, and SPME-GC/MS analysis. While few differences were observed in orthonasal assay (without saliva), interesting results were obtained for retronasal aroma. Biophenols caused generally the lowest headspace release of almost all volatile compounds. However, only ethyl esters and linalool concentrations were significantly lower in retronasal than orthonasal assay. Saliva also caused higher concentration of hexanal, probably due to hydroperoxide lyase (HPL) action on linoleyl hydroperoxides. Epicatechin was compared to EVOO phenolics and the behaviour was dramatically different, likely to be due to salivary protein-tannin binding interactions, which influenced aroma headspace release. These results were also confirmed using two extra virgin olive oils. PMID:25794752

  10. A calorimetric and spectroscopic comparison of the effects of cholesterol and its sulfur-containing analogs thiocholesterol and cholesterol sulfate on the thermotropic phase behavior and organization of dipalmitoylphosphatidylcholine bilayer membranes.

    PubMed

    Benesch, Matthew G K; Lewis, Ruthven N A H; McElhaney, Ronald N

    2016-02-01

    We performed differential scanning calorimetric (DSC) and Fourier transform infrared (FTIR) spectroscopic studies of the effects of cholesterol (Chol), thiocholesterol (tChol) and cholesterol sulfate (CholS) on the thermotropic phase behavior and organization of dipalmitoylphosphatidylcholine (DPPC) bilayer membranes. Our DSC results indicate that Chol and tChol incorporation produce small temperature increases in the main phase transition broad component while CholS markedly decreases it, but Chol decreases cooperativity and enthalpy more strongly than CholS and especially tChol. Hence, Chol and tChol thermally stabilize fluid DPPC bilayer sterol-rich domains while CholS markedly destabilizes them, and CholS and particularly tChol are less miscible in such domains. Our FTIR spectroscopic results indicate that Chol incorporation increases the rotational conformational order of fluid DPPC bilayers to a slightly and somewhat greater degree than tChol and CholS, respectively, consistent with our DSC findings. Also, Chol and CholS produce comparable degrees of H-bonding (hydration) of the DPPC ester carbonyls in fluid bilayers, whereas tChol increases H-bonding. At low temperatures, Chol is fully soluble in gel-state DPPC bilayers, whereas tChol and CholS are not. Thus tChol and CholS incorporation can produce considerably different effects on DPPC bilayers. In particular, the tChol thiol group markedly reduces its lateral miscibility and increases DPPC carbonyl H-bonding without significantly affecting the other characteristic effects of Chol itself, while the CholS sulfate group significantly reduces its ability to thermally stabilize and order fluid DPPC membranes. This latter result suggests that the molecular basis for the purported ability of CholS to "stabilize" various biological membranes should be re-examined. PMID:26585353

  11. Characterizing the secondary hydration shell on hydrated myoglobin, hemoglobin, and lysozyme powders by its vitrification behavior on cooling and its calorimetric glass-->liquid transition and crystallization behavior on reheating.

    PubMed Central

    Sartor, G; Hallbrucker, A; Mayer, E

    1995-01-01

    For hydrated metmyoglobin, methemoglobin, and lysozyme powders, the freezable water fraction of between approximately 0.3-0.4 g water/g protein up to approximately 0.7-0.8 g water/g protein has been fully vitrified by cooling at rates up to approximately 1500 K min-1 and the influence of cooling rate characterized by x-ray diffractograms. This vitreous but freezable water fraction started to crystallize at approximately 210 K to cubic ice and at approximately 240 K to hexagonal ice. Measurements by differential scanning calorimetry have shown that this vitreous but freezable water fraction undergoes, on reheating at a rate of 30 K min-1, a glass-->liquid transition with an onset temperature of between approximately 164 and approximately 174 K, with a width of between approximately 9 and approximately 16 degrees and an increase in heat capacity of between approximately 20 and approximately 40 J K-1 (mol of freezable water)-1 but that the glass transition disappears upon crystallization of the freezable water. These calorimetric features are similar to those of water imbibed in the pores of a synthetic hydrogel but very different from those of glassy bulk water. The difference to glassy bulk water's properties is attributed to hydrophilic interaction and H-bonding of the macromolecules' segments with the freezable water fraction, which thereby becomes dynamically modified. Abrupt increase in minimal or critical cooling rate necessary for complete vitrification is observed at approximately 0.7-0.8 g water/g protein, which is attributed to an abrupt increase of water's mobility, and it is remarkably close to the threshold value of water's mobility on a hydrated protein reported by Kimmich et al. (1990, Biophys. J. 58:1183). The hydration level of approximately 0.7-0.8 g water/g protein is approximately that necessary for completing the secondary hydration shell. PMID:8599674

  12. Calorimetric, spectroscopic and structural investigations of phase polymorphism in [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3}. Part I

    SciTech Connect

    Dolega, Diana; Mikuli, Edward; Inaba, Akira; Gorska, Natalia; Holderna-Natkaniec, Krystyna; Nitek, Wojciech

    2013-01-15

    Four crystalline phases of the coordination compound [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3} are identified by adiabatic calorimetry. Three phase transitions, one at T{sub C3}(IV{yields}III)=30.7 K, the second at T{sub C2}(III{yields}II)=91.7 K (both accompanied by comparable entropy changes 3.0 and 3.1 J K{sup -1} mol{sup -1}, respectively) and the third at T{sub C1}(II{yields}I)=241.6 K (accompanied by an entropy change of 8.1 J K{sup -1} mol{sup -1}) were discovered. X-ray single crystal diffraction (at 293 K) demonstrates that phase I is a highly dynamic disordered cubic phase (Fm3{sup Macron }m, No. 225) with two types of BF{sub 4}{sup -} anions differing in a degree of disorder. In phase II (at 170 K) the structure remains cubic (Ia3{sup Macron }, No. 206), with two different types of cations and four different types of anions. Splitting of certain IR bands connected with NH{sub 3} ligands at the observed phase transitions suggests a lowering of the symmetry of the [Ru(NH{sub 3}){sub 6}]{sup 3+} complex cation. Both NH{sub 3} ligands and BF{sub 4}{sup -} anions perform fast reorientations ({tau}{sub R} Almost-Equal-To 10{sup -12} s), which are significantly slowed down below the phase transition at T{sub C3}. {sup 1}H NMR studies led to estimate the values of the activation energy of NH{sub 3} ligands reorientation in the phases II and I as equal to {approx}8 kJ mol{sup -1}. In phase I the whole hexammineruthenium(III) cations reorientation as a tumbling process can be noticed. The activation energy value of this motion is {approx}24 kJ mol{sup -1}. {sup 19}F NMR studies give the values of the activation energy of BF{sub 4}{sup -} anions reorientation as {approx}6 kJ mol{sup -1}. Above the phase transition temperature half of BF{sub 4}{sup -} anions perform a tumbling motion with E{sub a} Almost-Equal-To 8 kJ mol{sup -1}. - Graphical abstract: A series of complementary methods, such as Adiabatic Calorimetry, Differential Scanning Calorimetry, Fourier Transform-Far and Middle Spectroscopy, proton and fluorine Nuclear Magnetic Resonance and structural methods reveal information about phase transitions in [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3}. Highlights: Black-Right-Pointing-Pointer Three novel phase transitions are found in [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3}. Black-Right-Pointing-Pointer The thermodynamic parameters of the phase transitions are derived. Black-Right-Pointing-Pointer The transitions are of order-disorder type. Black-Right-Pointing-Pointer The complex belongs to Fm3{sup Macron }m at 293 K and its symmetry changes to Ia3{sup Macron} at 170 K. Black-Right-Pointing-Pointer [Ru(NH{sub 3}){sub 6}](BF{sub 4}){sub 3} is a highly dynamically disordered crystal.

  13. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  14. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-09-07

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 figures.

  15. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1994-06-14

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  16. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1994-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  17. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  18. Catalytic Decomposition of Organophosphorus Compounds

    NASA Astrophysics Data System (ADS)

    Michalkova, A.; Leszczynski, J.

    Organophosphorus compounds have several applications (agricultural, industrial, and military). Nevertheless, assessments of the hazards from these applications quite often do not take into account chemical processes during their interactions with environment. The management of contaminants requires considerable knowledge and understanding of contaminant behavior. Unique properties of clay minerals and metal oxides, such as high adsorption and catalytic ability, have resulted in their applications as natural adsorbents and catalysts in the development of cleanup technologies. Knowledge of molecular structure, transformation mechanisms, and the spectrum of potential intermediates/products of the contaminant decomposition is helpful for developing remediation processes. An understanding of the physical characteristics of the adsorption sites of selected soil ingredients, the physical and chemical characteristics of the contaminant, details of sorption of contaminants on soil and in water solution, and also their distribution within the environment is of particular interest. Application of computational chemistry (CC) can provide deeper insight into the aforementioned characteristics of organophosphorus compounds.

  19. [Perfluorinated compounds in potable water].

    PubMed

    Rostkowski, Paweł; Taniyasu, Sachi; Yamashita, Nobuyoshi; Falandysz, Jerzy

    2008-01-01

    In a pilot study perfluorinated compounds such as perfluorobutane sulfonate (PFBS), perfluorohexane suflonate (PFHS), perfluorooctane sulfonate (PFOS), perfluorooctane sulfonamide (PFOSA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA) have been determined in the Japanese and Polish brands of bottled mineral water and in tap water. Bottled mineral water from both countries contained ultratrace amounts of some perfluorinated compounds, and higher degree of contamination showed tap water. PFOS and PFOA concentrations were much below threshold level for toxic effects, and Hazard Quotient (HQ) was much < 1. PMID:19143425

  20. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  1. Superconductivity in graphite intercalation compounds

    SciTech Connect

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P. M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  2. Superconductivity in graphite intercalation compounds

    DOE PAGESBeta

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P. M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic statesmore » and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.« less

  3. Heuristics for chemical compound matching.

    PubMed

    Hattori, Masahiro; Okuno, Yasushi; Goto, Susumu; Kanehisa, Minoru

    2003-01-01

    We have developed an efficient algorithm for comparing two chemical compounds, where the chemical structure is treated as a 2D graph consisting of atoms as vertices and covalent bonds as edges. Based on the concept of functional groups in chemistry, 68 atom types (vertex types) are defined for carbon, nitrogen, oxygen, and other atomic species with different environments, which has enabled detection of biochemically meaningful features. Maximal common subgraphs of two graphs can be found by searching for maximal cliques in the association graph, and we have introduced heuristics to accelerate the clique finding. Our heuristic procedure is controlled by some adjustable parameters. Here we applied our procedure to the latest KEGG/LIGAND database with different sets of parameters, and demonstrated the correlation of parameters in our algorithm with the distribution of similarity scores and/or the execution time. Finally, we showed the effectiveness of our heuristics for compound pairs along metabolic pathways. PMID:15706529

  4. Thin compound-eye camera.

    PubMed

    Duparré, Jacques; Dannberg, Peter; Schreiber, Peter; Bräuer, Andreas; Tünnermann, Andreas

    2005-05-20

    An artificial compound-eye objective fabricated by micro-optics technology is adapted and attached to a CMOS sensor array. The novel optical sensor system with an optics thickness of only 0.2 mm is examined with respect to resolution and sensitivity. An optical resolution of 60 x 60 pixels is determined from captured images. The scaling behavior of artificial compound-eye imaging systems is analyzed. Cross talk between channels fabricated by different technologies is evaluated, and the influence on an extension of the field of view by addition of a (Fresnel) diverging lens is discussed. The lithographic generation of opaque walls between channels for optical isolation is experimentally demonstrated. PMID:15929282

  5. [Bioactive compounds from marine actinomycetes].

    PubMed

    Mikha?lov, V V; Kuznetsova, T A; Eliakov, G B

    1995-01-01

    Studies of the origin of bioactive metabolites of marine actinomycetes are reviewed. Structures and properties of new metabolites from indigenous marine bacteria from Actinomycetales order, such as a benzanthraquinone antibiotic from a strain of the Chainia purpurogena, istamycins, aplasmomycins, altemicidin, new phenazine esters. C13-butanolide, marinone and debromomarinone, palmyromycin, urauchimicins and some others compounds are presented. Prospects of marine biotechnology and microbiology (with considerable emphasis on the development of the basis biology of marine microorganisms in cultures collection) are discussed. PMID:7710421

  6. Compound semiconductor optical waveguide switch

    DOEpatents

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  7. Human detoxification of perfluorinated compounds.

    PubMed

    Genuis, S J; Birkholz, D; Ralitsch, M; Thibault, N

    2010-07-01

    There has been no proven method thus far to accelerate the clearance of potentially toxic perfluorinated compounds (PFCs) in humans. PFCs are a family of commonly used synthetic compounds with many applications, including repelling oil and stains on furniture, clothing, carpets and food packaging, as well as in the manufacturing of polytetrafluoroethylene - a non-stick surfacing often used in cookware (e.g. Teflon(r)). Some PFCs remain persistent within the environment due to their inherent chemical stability, and are very slowly eliminated from the human body due, in part, to enterohepatic recirculation. Exposure to PFCs is widespread and some subpopulations, living in proximity to or working in fluorochemical manufacturing plants, are highly contaminated. PFC bioaccumulation has become an increasing public health concern as emerging evidence suggests reproductive toxicity, neurotoxicity and hepatotoxicity, and some PFCs are considered to be likely human carcinogens. A case history is presented where an individual with high concentrations of PFCs in serum provided: (1) sweat samples after use of a sauna; and (2) stool samples before and after oral administration of each of two bile acid sequestrants - cholestyramine (CSM) and saponin compounds (SPCs). Stool samples before and after use of a cation-exchange zeolite compound were also examined. PFCs found in serum were not detected in substantial quantities in sweat or in stool prior to treatment. Minimal amounts of perfluorooctanoic acid, but no other PFCs, were detected in stool after SPC use; minimal amounts of perfluorooctanesulfonate, but no other PFCs, were detected in stool after zeolite use. All PFC congeners found in serum were detected in stool after CSM use. Serum levels of all PFCs subsequently declined after regular use of CSM. Further study is required but this report suggests that CSM therapy may facilitate gastrointestinal elimination of some PFCs from the human body. PMID:20621793

  8. Neuroprotective compounds of Tilia amurensis

    PubMed Central

    Lee, Bohyung; Weon, Jin Bae; Eom, Min Rye; Jung, Youn Sik; Ma, Choong Je

    2015-01-01

    Background: Tilia amurensis (Tiliacese) has been used for anti-tumor and anti-inflammatory in Korea, China, and Japan. Objective: In this study, we isolated five compounds from T. amurensis and determined whether protected neuronal cells against glutamate-induced oxidative stress in HT22 cells. Materials and Methods: Compounds were isolated using chromatographic techniques including silica gel, Sephadex LH-20 open column and high performance liquid chromatography analysis, and evaluated neuroprotective effect in HT22 cells by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Results: β-D-fructofuranosyl α-D-glucopyranoside (1), (-)-epicatechin (2), nudiposide (3), lyoniside (4), and scopoletin (5) were isolated by bioactivity-guided fractionation from the ethyl acetate fraction of T. amurensis. Among them, (-)-epicatechin, nudiposide, lyoniside, and scopoletin had significant neuroprotective activities against glutamate-injured neurotoxicity in HT22 cells. Conclusion: These results demonstrated that compound two, three, four, and five have a pronounced protective effect against glutamate-induced neurotoxicity in HT22 cells. PMID:26664019

  9. Natural Compounds Modulating Mitochondrial Functions

    PubMed Central

    Gibellini, Lara; Bianchini, Elena; De Biasi, Sara; Nasi, Milena; Cossarizza, Andrea; Pinti, Marcello

    2015-01-01

    Mitochondria are organelles responsible for several crucial cell functions, including respiration, oxidative phosphorylation, and regulation of apoptosis; they are also the main intracellular source of reactive oxygen species (ROS). In the last years, a particular interest has been devoted to studying the effects on mitochondria of natural compounds of vegetal origin, quercetin (Qu), resveratrol (RSV), and curcumin (Cur) being the most studied molecules. All these natural compounds modulate mitochondrial functions by inhibiting organelle enzymes or metabolic pathways (such as oxidative phosphorylation), by altering the production of mitochondrial ROS and by modulating the activity of transcription factors which regulate the expression of mitochondrial proteins. While Qu displays both pro- and antioxidant activities, RSV and Cur are strong antioxidant, as they efficiently scavenge mitochondrial ROS and upregulate antioxidant transcriptional programmes in cells. All the three compounds display a proapoptotic activity, mediated by the capability to directly cause the release of cytochrome c from mitochondria or indirectly by upregulating the expression of proapoptotic proteins of Bcl-2 family and downregulating antiapoptotic proteins. Interestingly, these effects are particularly evident on proliferating cancer cells and can have important therapeutic implications. PMID:26167193

  10. Antimalarial compounds from Grewia bilamellata.

    PubMed

    Ma, Cuiying; Zhang, Hong Jie; Tan, Ghee Teng; Hung, Nguyen Van; Cuong, Nguyen Manh; Soejarto, D Doel; Fong, Harry H S

    2006-03-01

    Bioassay-directed fractionation led to the isolation of 12 compounds from a sample of the dried leaves, twigs, and stems of Grewia bilamellata. Five of the isolates, 3alpha,20-lupandiol (1), grewin (2), nitidanin (4), 2alpha,3beta-dihydroxy-olean-12-en-28-oic acid (5), and 2,6-dimethoxy-1-acetonylquinol (6), showed varying degrees of in vitro antimalarial activity against Plasmodium falciparum, but were devoid of significant cytotoxicity to the human oral epidermoid KB cancer cell line. Of the 12 isolates, compounds 1, 2, and 3 (bilagrewin) were determined to be a new triterpene, a new coumarinolignan, and a new neolignan, respectively. Other known compounds isolated in this study were 8-O-4' neolignan guaiacylglycerol-beta-coniferyl ether isomers (threo and erythro), cleomiscosin D, icariol A(2), ciwujiatone, and daucosterol. The structures of 1-3 were elucidated and identified on the basis of spectroscopic data including 1D and 2D NMR analysis. PMID:16562832

  11. BIOSYNTHESIS OF NITRO COMPOUNDS I.

    PubMed Central

    Shaw, Paul D.; Wang, Nancy

    1964-01-01

    Shaw, Paul D. (University of Illinois, Urbana), and Nancy Wang. Biosynthesis of nitro compounds. I. Nitrogen and carbon requirements for the biosynthesis of β-nitropropionic acid by Penicillium atrovenetum. J. Bacteriol. 88:1629–1635. 1964.—β-Nitropropionic acid was produced by Penicillium atrovenetum when this fungus was grown on a Raulin-Thom medium in shake flasks. The nitro compound was formed in the early stages of growth, and the total amount in the medium decreased when the fungus reached the end of the log phase. When increasing amounts of nitrate were substituted for the ammonia in the growth medium, production of β-nitropropionic acid decreased. Aspartic acid did not promote the synthesis of the nitro compound unless either ammonium chloride or sodium tartrate was also added to the medium. The addition of small amounts of hydroxylamine or sodium nitrite to the Raulin-Thom medium stimulated β-nitropropionic acid production to a greater degree on a molar basis than the amount of hydroxylamine or nitrite added. The nature of possible precursors to the nitro group of β-nitropropionic acid is discussed. PMID:14240949

  12. Compound facial expressions of emotion.

    PubMed

    Du, Shichuan; Tao, Yong; Martinez, Aleix M

    2014-04-15

    Understanding the different categories of facial expressions of emotion regularly used by us is essential to gain insights into human cognition and affect as well as for the design of computational models and perceptual interfaces. Past research on facial expressions of emotion has focused on the study of six basic categories--happiness, surprise, anger, sadness, fear, and disgust. However, many more facial expressions of emotion exist and are used regularly by humans. This paper describes an important group of expressions, which we call compound emotion categories. Compound emotions are those that can be constructed by combining basic component categories to create new ones. For instance, happily surprised and angrily surprised are two distinct compound emotion categories. The present work defines 21 distinct emotion categories. Sample images of their facial expressions were collected from 230 human subjects. A Facial Action Coding System analysis shows the production of these 21 categories is different but consistent with the subordinate categories they represent (e.g., a happily surprised expression combines muscle movements observed in happiness and surprised). We show that these differences are sufficient to distinguish between the 21 defined categories. We then use a computational model of face perception to demonstrate that most of these categories are also visually discriminable from one another. PMID:24706770

  13. Rotor phases in compound semiconductors

    SciTech Connect

    Price, D.L.; Saboungi, M.L.; Howells, W.S.

    1994-11-01

    Quasi-elastic neutron scattering is used to study the disordering processes in two classes of semiconductor: I-IV Zintl compounds and the phosphorus-selenium system. Two alkali-metal-polyvalent metal Zintl compounds, CsPb and NaSn, exhibit a two-stage melting process with high-temperature solid phases characterized by rapid dynamical disorder. In CsPb this disorder is clearly associated with rapid reorientations of polyanions with the cations participating in the dynamical disorder on the same time scale. In NaSn the disorder is associated with fast reorientations of the polyanions closely coupled to a slower migration of the cations. The two high-temperature solid phases of the molecular crystal P{sub 4}Se{sub 3} are confirmed to be rotor phases with small but significant differences in the reorientational motions in the two phases. Zintl compounds are formed from an electropositive metal A and an electronegative metal on semimetal M. Electron transfer from A to M, along with directional bonding between the M-ions, leads to chemical behavior in these ions characteristic of elements to the right of M in the periodic table.

  14. Bioactive compounds from northern plants.

    PubMed

    Hohtola, Anja

    2010-01-01

    Northern conditions are characterised by long days with much light and low temperatures during the growing season. It has been chimed that herbs and berries grown in the north are stronger tasting compared to those of southern origin. The compounds imparting aroma and color to berries and herbs are secondary metabolites which in plants mostly act as chemical means of defense. Recently, the production of secondary metabolites using plant cells has been the subject of expanding research. Light intensity, photoperiod and temperature have been reported to influence the biosynthesis of many secondary metabolites. Native wild aromatic and medicinal plant species of different families are being studied to meet the needs of raw material for the expanding industry of e.g., health-promoting food products known as nutraceutics. There are already a large number of known secondary compounds produced by plants, but the recent advances in modern extraction and analysis should enable many more as yet unknown compounds to be found, characterised and utilised. Rose root (Rhodiola rosea) is a perennial herbaceous plant which inhabits mountain regions throughout Europe, Asia and east coastal regions of North America. The extract made from the rhizomes acts as a stimulant like the Ginseng root. Roseroot has been categorized as an adaptogen and is reported to have many pharmacological properties. The biologically active components of the extract are salitroside tyrosol and cinnamic acid glycosides (rosavin, rosarin, rosin). Round-leaved sundew (Drosera rotundifolia L.) has circumboreal distribution. It inhabits nutrient-poor, moist and sunny areas such as peat bogs and wetlands. Sundew leaves are collected from the wild-type for various medicinal preparations and can be utilized in treating e.g., as an important "cough-medicine" for different respiratory diseases. The antimicrobial activity of extracts of aerial parts against various bacteria has been investigated. Drosera produces various secondary metabolites. The most abundant, among these compounds, are the naphthoquinones. Bilberry (Vaccinium myrtillus) is a characteristic field layer species in boreal forests. Bilberry and other northern Vaccinium species, berries and leaves, contain high amounts of phenolic compounds. Bilberries are known for its exceptionally high amounts ofanthocyanins with powerful antioxidant capacity. They have been shown to possess beneficial health effects, like having a protective role in cardiovascular diseases and cancer. Many flavonoids also seem to have antiviral, antibacterial, antifungal and antiallergenic properties. The effect of ingested cranberry (V. oxycoccus) juice has been shown to prevent urinary tract infections in women. PMID:21520706

  15. Deuterium permeation through EPDM rubber compounds

    SciTech Connect

    Zapp, P.E.

    1988-01-01

    The permeation of deuterium through a specially formulated compound of ethylene propylene diene rubber was measured in the temperature range of 26/degree/C to 120/degree/C. The results were similar to permeation through two commercial compounds of this elastomer. Permeation was reduced after gamma irradiation (in the presence of hydrogen gas to simulate a tritium exposure). However the reduction was smaller than that experienced by the two commercial compounds. Radiation damage is apparently less severe in the special compound. It is possible that mechanical properties such as compression set may be influenced less by ionizing radiation in this compound as compared with the commercial compounds. 4 figs., 1 tab.

  16. Removal of phenolic compounds in soil

    SciTech Connect

    Nam-Koong, W.

    1988-01-01

    The objective of this research was an evaluation of the removal rates of phenolic compounds in soil. Seventeen phenolic compounds with similar structure were chosen. Relative toxicity of phenolic compounds also was determined by the Microtox{sup TM} System to evaluate the relationship between the toxicity of the phenolic compounds and removal rate. The amount of ATP in the soil was measured by a Lumac/3M biocounter to evaluate any effect of phenolic compounds on the soil microbial activity. Preferential removal of phenolic compounds occurred in mixtures. The presence of phenol and/or o-cresol reduced the removal rate of 2,4-dichlorophenol. Reapplications of the phenolic compounds did not change the removal rate of the compounds. There was good correlation between the relative toxicity of phenolic compounds and zero order removal rates. The less toxic phenolic compounds were removed more rapidly. No lag phase was observed for the removal of phenolic compounds when the compounds were applied to soil below the toxic level. Phenolic compounds had a significant effect on soil microbial activity based on ATP measurement. The increase in soil ATP was related to a rapid removal of phenol. A gradual decrease in soil ATP was observed with the removal of 2,4-dichlorophenol.

  17. BTF Potts compound texture model

    NASA Astrophysics Data System (ADS)

    Haindl, Michal; Reměs, Václav; Havlíček, Vojtěch

    2015-03-01

    This paper introduces a method for modeling mosaic-like textures using a multispectral parametric Bidirectional Texture Function (BTF) compound Markov random field model (CMRF). The primary purpose of our synthetic texture approach is to reproduce, compress, and enlarge a given measured texture image so that ideally both natural and synthetic texture will be visually indiscernible, but the model can be easily applied for BFT material editing. The CMRF model consist of several sub-models each having different characteristics along with an underlying structure model which controls transitions between these sub models. The proposed model uses the Potts random field for distributing local texture models in the form of analytically solvable wide-sense BTF Markovian representation for single regions among the fields of a mosaic approximated by the Voronoi diagram. The control field of the BTF-CMRF is generated by the Potts random field model build on top of the adjacency graph of a measured mosaic. The compound random field synthesis combines the modified fast Swendsen- Wang Markov Chain Monte Carlo sampling of the hierarchical Potts MRF part with the fast and analytical synthesis of single regional BTF MRFs. The local texture regions (not necessarily continuous) are represented by an analytical BTF model which consists of single factors modeled by the adaptive 3D causal auto-regressive (3DCAR) random field model which can be analytically estimated as well as synthesized. The visual quality of the resulting complex synthetic textures generally surpasses the outputs of the previously published simpler non-compound BTF-MRF models.

  18. Menthol and related cooling compounds.

    PubMed

    Eccles, R

    1994-08-01

    Menthol and related cooling compounds such as 'coolant agent 10', are widely used in products ranging from common cold medications to toothpastes, confectionery, cosmetics and pesticides. The review brings together a range of information on production and chemistry of menthol, and its metabolism, mechanism of action, structure-activity relationships, pharmacology and toxicology. In particular, the coolant action and carminative actions of menthol are discussed in terms of actions on calcium conductance in sensory nerves and smooth muscle. The actions of menthol on the nose, respiratory reflexes, oral cavity, skin and gastrointestinal tract are reviewed. PMID:7529306

  19. Turbo-compound compressor system

    SciTech Connect

    Watanabe, K.; Horiai, K.; Mashiko, T.; Kato, H.; Yamaguchi, H.; Nishiyama, T.

    1987-07-14

    This patent describes a turbo-compound compressor system including a booster compressor connected to a power recovery turbine disposed downstream of the outlet of an expansion turbine in a turbocharger for an internal combustion engine and drivable by the exhaust gas and a rotary positive-displacement air compressor drivable by the engine. The air is delivered by the booster compressor supplied to the rotary positive-displacement air compressor through a pipeline means having a throttle valve. The improvement comprises a bypass line connected to the pipeline means for preventing surging and having a closing valve.

  20. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.

    2009-02-10

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  1. Antimalarial compounds from Parinari capensis.

    PubMed

    Uys, Arina C U; Malan, Sarel F; van Dyk, Sandra; van Zyl, Robyn L

    2002-08-19

    The antimalarial activity of the raw petroleum ether and dichloromethane extracts of the stems of Parinari capensis (Chrysobalanceae) was determined. Phytochemical investigation of these extracts led to the isolation of three diterpene lactones that possess antimalarial activity with IC(50) values of 0.54, 0.67, and 1.57 microg/mL. Although their antimalarial activity is promising, the toxicity profiles of these diterpene lactones prevent further biological evaluation. They could however be used effectively as lead compounds in the synthesis of novel antimalarial agents. PMID:12127529

  2. Volatile organic compound sensor system

    SciTech Connect

    Schabron, John F.; Rovani, Jr., Joseph F.; Bomstad, Theresa M.; Sorini-Wong, Susan S.; Wong, Gregory K.

    2011-03-01

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  3. Polyfluorinated Compounds: Past, Present, and Future

    EPA Science Inventory

    Interest and concern about polyfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), erfluorooctanoic acid (PFOA), and an increasing number of other related compounds is growing as more is learned about these ubiquitous anthropogenic substances. Many of these co...

  4. Groundwater Dating with Atmospheric Halogenated Compounds

    USGS Publications Warehouse

    Haase, Karl B.; Busenberg, Eurybiades

    2014-01-01

    "Atmospheric environmental releases refer to the emission of stable, long-lived compounds of solely anthropogenic origin into the atmosphere and the use of the compounds to estimate dates of their incorporation into groundwater."

  5. Hyperpolarizable compounds and devices fabricated therefrom

    DOEpatents

    Therien, Michael J.; DiMagno, Stephen G.

    1998-01-01

    Substituted compounds having relatively large molecular first order hyperpolarizabilities are provided, along with devices and materials containing them. In general, the compounds bear electron-donating and electron-withdrawing chemical substituents on a polyheterocyclic core.

  6. Aroma compounds in fresh cut pomegranate arils.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little published information exists regarding flavor and aroma compounds in pomegranate (Punica granatum). Although arils have fruity and sweet characteristics, we found no publications describing actual compounds responsible for their typical flavor. Since most commercial usage of pomegranates in...

  7. Lipid encapsulated phenolic compounds by fluidization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phenolic compounds exhibit antioxidant and antimicrobial activities with applications as functional food and feed additives. Ferulic acid, a phenolic compound present in grain crops and lignocellulose biomass, was encapsulated with saturated triglycerides using a laboratory fluidizer. Stability of t...

  8. Therapeutic Phytogenic Compounds for Obesity and Diabetes

    PubMed Central

    Jung, Hee Soong; Lim, Yun; Kim, Eun-Kyoung

    2014-01-01

    Natural compounds have been used to develop drugs for many decades. Vast diversities and minimum side effects make natural compounds a good source for drug development. However, the composition and concentrations of natural compounds can vary. Despite this inconsistency, half of the Food and Drug Administration (FDA)-approved pharmaceuticals are natural compounds or their derivatives. Therefore, it is essential to continuously investigate natural compounds as sources of new pharmaceuticals. This review provides comprehensive information and analysis on natural compounds from plants (phytogenic compounds) that may serve as anti-obesity and/or anti-diabetes therapeutics. Our growing understanding and further exploration of the mechanisms of action of the phytogenic compounds may afford opportunities for development of therapeutic interventions in metabolic diseases. PMID:25421245

  9. Hyperpolarizable compounds and devices fabricated therefrom

    DOEpatents

    Therien, M.J.; DiMagno, S.G.

    1998-07-21

    Substituted compounds having relatively large molecular first order hyperpolarizabilities are provided, along with devices and materials containing them. In general, the compounds bear electron-donating and electron-withdrawing chemical substituents on a polyheterocyclic core. 13 figs.

  10. Two new acetylenic compounds from Asparagus officinalis.

    PubMed

    Li, Xue-Mei; Cai, Jin-Long; Wang, Wen-Xiang; Ai, Hong-Lian; Mao, Zi-Chao

    2016-04-01

    Two new acetylenic compounds, asparoffins A (1) and B (2), together with two known compounds, nyasol (3) and 3″-methoxynyasol (4), were isolated from stems of Asparagus officinalis. The structures of two new compounds were elucidated on the basis of detailed spectroscopic analyses (UV, IR, MS, 1D, and 2D NMR). All compounds were evaluated for their cytotoxicities against three human cancer cell lines. PMID:26558641

  11. Semiconducting compounds and devices incorporating same

    DOEpatents

    Marks, Tobin J.; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2016-01-19

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  12. Semiconducting compounds and devices incorporating same

    SciTech Connect

    Marks, Tobin J; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2014-06-17

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  13. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, Reid A.; Chen, Wen S.

    1985-01-01

    A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

  14. The Modification of Compounds by Attributive Adjectives

    ERIC Educational Resources Information Center

    Berg, Thomas

    2011-01-01

    This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun

  15. The Modification of Compounds by Attributive Adjectives

    ERIC Educational Resources Information Center

    Berg, Thomas

    2011-01-01

    This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun…

  16. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: HD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  17. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  18. Compound prism design principles, I

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    Prisms have been needlessly neglected as components used in modern optical design. In optical throughput, stray light, flexibility, and in their ability to be used in direct-view geometry, they excel over gratings. Here we show that even their well-known weak dispersion relative to gratings has been overrated by designing doublet and double Amici direct-vision compound prisms that have 14° and 23° of dispersion across the visible spectrum, equivalent to 800 and 1300 lines/mm gratings. By taking advantage of the multiple degrees of freedom available in a compound prism design, we also show prisms whose angular dispersion shows improved linearity in wavelength. In order to achieve these designs, we exploit the well-behaved nature of prism design space to write customized algorithms that optimize directly in the nonlinear design space. Using these algorithms, we showcase a number of prism designs that illustrate a performance and flexibility that goes beyond what has often been considered possible with prisms. PMID:22423145

  19. Prebiotic Evolution of Nitrogen Compounds

    NASA Technical Reports Server (NTRS)

    Arrhenius, G.

    1999-01-01

    Support from this four year grant has funded our research on two general problems. One involves attempts to model the abiotic formation of simple source compounds for functional biomolecules, their concentration from dilute state in the hydrosphere and, in several cases, surface induced reactions to form precursor monomers for bioactive end products (refs. 1-5). Because of the pervasiveness and antiquity of phosphate based biochemistry and the catalytic activity of RNA we have exploring the hypothesis of an RNA World as an early stage in the emergence of life. This concept is now rather generally considered, but has been questioned due to the earlier lack of an experimentally demonstrated successful scheme for the spontaneous formation of ribose phosphate, the key backbone molecule in RNA. That impediment has now been removed. This has been achieved by demonstrating probable sources of activated (condensed) highly soluble and strongly sorbed phosphates in nature (Refs. 1,2) and effective condensation of aldehyde phosphates to form ribose phosphate in high yield (ref.6), thereby placing the RNA World concept on a somewhat safer experimental footing. Like all work in this field these experiments are oversimplifications that largely ignore competing side reactions with other compounds expected to be present. None the less our choice of experimental conditions aim at selective processes that eliminate interfering reactions. We have also sought to narrow the credibility gap by simulating geophysically and geochemically plausible conditions surrounding the putative prebiotic reactions.

  20. Valuable compounds in macroalgae extracts.

    PubMed

    Andrade, Paula B; Barbosa, Mariana; Matos, Rui Pedro; Lopes, Graciliana; Vinholes, Juliana; Mouga, Teresa; Valentão, Patrícia

    2013-06-01

    Bioactive compounds present in ethanolic extracts from 18 macroalgae of the Portuguese coast were analysed by gas chromatography-mass spectrometry (GC-MS), leading to the characterization of 14 compounds: proline, phloroglucinol, mannitol, 8 fatty acids and 3 sterols. A dose-dependent response against enzymes with biological significance (α-glucosidase, acetylcholinesterase and butyrylcholinesterase) and free radicals (DPPH, nitric oxide, superoxide and hydroxyl) was found, Phaeophyta being the most promising group. A PCA analysis was performed and allowed the establishment of a correlation between the algae chemical composition and the biological activity. Cystoseira tamariscifolia (Hudson) Papenfuss, Cystoseira nodicaulis (Withering) M. Roberts, Cystoseira usneoides (Linnaeus) M. Roberts and Fucus spiralis Linnaeus are among the most active species, which is in accordance with their higher contents in phloroglucinol, mannitol, oleic, arachidonic and eicosapentaenoic acids, and fucosterol. The results point to the potential interest of the use of Phaeophyta species as food additives, due to their potent antiradical activities, and especially highlights the importance of F. spiralis in the food chain of Mediterranean countries. Moreover, the incorporation of the extracts of these species in food products, nutraceutical and pharmaceutical preparations for human health should also be instigated, since they can suppress hyperglycemia and inhibit cholinesterases. PMID:23411314

  1. INSENSITIVE HIGH-NITROGEN COMPOUNDS

    SciTech Connect

    D. CHAVEZ; ET AL

    2001-03-01

    The conventional approach to developing energetic molecules is to chemically place one or more nitro groups onto a carbon skeleton, which is why the term ''nitration'' is synonymous to explosives preparation. The nitro group carries the oxygen that reacts with the skeletal carbon and hydrogen fuels, which in turn produces the heat and gaseous reaction products necessary for driving an explosive shock. These nitro-containing energetic molecules typically have heats of formation near zero and therefore most of the released energy is derived from the combustion process. Our investigation of the tetrazine, furazan and tetrazole ring systems has offered a different approach to explosives development, where a significant amount of the chemical potential energy is derived from their large positive heats of formation. Because these compounds often contain a large percentage of nitrogen atoms, they are usually regarded as high-nitrogen fuels or explosives. A general artifact of these high-nitrogen compounds is that they are less sensitive to initiation (e.g. by impact) when compared to traditional nitro-containing explosives of similar performances. Using the precursor, 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine, several useful energetic compounds based on the s-tetrazine system have been synthesized and studied. Some of the first compounds are 3,6-diamino-s-tetrazine-1,4-dioxide (LAX-112) and 3,6-dihydrazino-s-tetrazine (DHT). LAX-112 was once extensively studied as an insensitive explosive by Los Alamos; DHT is an example of a high-nitrogen explosive that relies entirely on its heat of formation for sustaining a detonation. Recent synthesis efforts have yielded an azo-s-tetrazine, 3,3'-azobis(6-amino-s-tetrazine) or DAAT, which has a very high positive heat of formation. The compounds, 4,4'-diamino-3,3'-azoxyfurazan (DAAF) and 4,4'-diamino-3,3'-azofurazan (DAAzF), may have important future roles in insensitive explosive applications. Neither DAAF nor DAAzF can be initiated by laboratory impact drop tests, yet both have in some aspects better explosive performances than 1,3,5-triamino-2,4,6-trinitrobenzene TATB--the standard of insensitive high explosives. The thermal stability of DAAzF is equal to that of hexanitrostilbene (HNS), yet it too is a better explosive performer. The recently discovered tetrazol derivative, 3,6-bis-(1H-1,2,3,4-tetrazol-5-ylamino)-s-tetrazine (BTATz) was measured to have exceptional positive heats of formation and to be insensitive to explosive initiation. Because of its high burn rate with low sensitivity to pressure, this material is of great interest to the propellant community.

  2. Structures and standard molar enthalpies of formation of a series of Ln(III)–Cu(II) heteronuclear compounds with pyrazine-2,3-dicarboxylic acid

    SciTech Connect

    Yang, Qi; Xie, Gang; Wei, Qing; Chen, Sanping Gao, Shengli

    2014-07-01

    Fifteen lanthanide–copper heteronuclear compounds, formulated as [CuLn{sub 2}(pzdc){sub 4}(H{sub 2}O){sub 6}]·xH{sub 2}O (1–6(x=2), 8(x=3), 9–10(x=4)); [CuLn{sub 2}(pzdc){sub 4}(H{sub 2}O){sub 4}]·xH{sub 2}O (7, 12–13, 15(x=4), 14(x=5), 11(x=8)) (Ln(III)=La(1); Ce(2); Pr(3); Nd(4); Sm(5); Eu(6); Gd(7); Tb(8); Dy(9); Ho(10); Er(11); Tm(12); Yb(13); Lu(14); Y(15); H{sub 2}pzdc (C{sub 6}H{sub 4}N{sub 2}O{sub 4})=pyrazine-2,3-dicarboxylic acid) have been hydrothermally synthesized. All compounds were characterized by element analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analyses confirm that all compounds are isostructural and feature a 3D brick-like framework structure with (4.6{sup 2}){sub 2}(4{sup 2}.6{sup 2}.8{sup 2})(6{sup 3}){sup 2}(6{sup 5}.8){sub 2} topology. Using 1 mol cm{sup −3} HCl(aq) as calorimetric solvent, with an isoperibol solution–reaction calorimeter, the standard molar enthalpies of formation of all compounds were determined by a designed thermochemical cycle. In addition, solid state luminescence properties of compounds 5, 6, 8 and 9 were studied in the solid state. - Graphical abstract: According to Hess' rule, the standard molar enthalpies of formation of Ln–Cu heterometallic coordination compounds were determined by a designed thermochemical cycle. - Highlights: • Fifteen lanthanide–copper heteronuclear isostructural compounds. • Structurally characterization by IR, X-ray diffraction and thermal analysis. • The standard molar enthalpy of formation. • Isoperibol solution–reaction calorimetry.

  3. Elastomer Compound Developed for High Wear Applications

    NASA Technical Reports Server (NTRS)

    Crawford, D.; Feuer, H.; Flanagan, D.; Rodriguez, G.; Teets, A.; Touchet, P.

    1993-01-01

    The U.S. Army is currently spending 300 million dollars per year replacing rubber track pads. An experimental rubber compound has been developed which exhibits 2 to 3 times greater service life than standard production pad compounds. To improve the service life of the tank track pads various aspects of rubber chemistry were explored including polymer, curing and reinforcing systems. Compounds that exhibited superior physical properties based on laboratory data were then fabricated into tank pads and field tested. This paper will discuss the compounding studies, laboratory data and field testing that led to the high wear elastomer compound.

  4. Mutagenicity of oxaspiro compounds with Salmonella.

    PubMed

    Sinsheimer, J E; Chakraborty, P K; Messerly, E A; Gaddamidi, V

    1989-10-01

    The spiro attachment of an epoxide group to a tetrahydropyran ring in the trichothecene mycotoxins has prompted this study of the mutagenicity and alkylation rates of the trichothecene, anguidine, and 5 related model oxaspiro compounds. While the model compounds were weak alkylating agents of 4-(4-nitrobenzyl)pyridine as a test nucleophile, anguidine lacks such activity. Also, while mutagenicity was not established for anguidine in Salmonella TA100, 3 of the oxaspiro compounds were weakly mutagenic and 2 compounds were toxic to the bacteria. The toxicity and mutagenicity of the model compounds are more related to their polarity than to their alkylation rates. PMID:2677708

  5. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, R.A.; Chen, W.S.

    1985-06-11

    Disclosed is a thin film heterojunction solar cell, said heterojunction comprising a p-type I-III-IV[sub 2] chalcopyrite substrate and an overlying layer of an n-type ternary mixed metal compound wherein said ternary mixed metal compound is applied to said substrate by introducing the vapor of a first metal compound to a vessel containing said substrate from a first vapor source while simultaneously introducing a vapor of a second metal compound from a second vapor source of said vessel, said first and second metals comprising the metal components of said mixed metal compound; independently controlling the vaporization rate of said first and second vapor sources; reducing the mean free path between vapor particles in said vessel, said gas being present in an amount sufficient to induce homogeneity of said vapor mixture; and depositing said mixed metal compound on said substrate in the form of a uniform composition polycrystalline mixed metal compound. 5 figs.

  6. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70.degree. C. and 500.degree. C. and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  7. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-01-05

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70 C and 500 C and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  8. METHOD OF RECOVERING URANIUM COMPOUNDS

    DOEpatents

    Poirier, R.H.

    1957-10-29

    S>The recovery of uranium compounds which have been adsorbed on anion exchange resins is discussed. The uranium and thorium-containing residues from monazite processed by alkali hydroxide are separated from solution, and leached with an alkali metal carbonate solution, whereby the uranium and thorium hydrorides are dissolved. The carbonate solution is then passed over an anion exchange resin causing the uranium to be adsorbed while the thorium remains in solution. The uranium may be recovered by contacting the uranium-holding resin with an aqueous ammonium carbonate solution whereby the uranium values are eluted from the resin and then heating the eluate whereby carbon dioxide and ammonia are given off, the pH value of the solution is lowered, and the uranium is precipitated.

  9. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

    1995-08-29

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

  10. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, Gregory D.; Moore, Glenn A.; Stone, Mark L.; Reagen, William K.

    1995-01-01

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

  11. New permanent magnets; manganese compounds.

    PubMed

    Coey, J M D

    2014-02-12

    The exponential growth of maximum energy product that prevailed in the 20th century has stalled, leaving a market dominated by two permanent magnet materials, Nd2Fe14B and Ba(Sr)Fe12O19, for which the maximum theoretical energy products differ by an order of magnitude (515 kJ m(-3) and 45 kJ m(-3), respectively). Rather than seeking to improve on optimized Nd-Fe-B, it is suggested that some research efforts should be devoted to developing appropriately priced alternatives with energy products in the range 100-300 kJ m(-3). The prospects for Mn-based hard magnetic materials are discussed, based on known Mn-based compounds with the tetragonal L10 or D022 structure or the hexagonal B81 structure. PMID:24469291

  12. Calorimetric measurement of energy of ultrasonic cleaners

    SciTech Connect

    Harding, W.B.

    1994-11-01

    The development of a calorimeter that measured the power within an ultrasonic cleaning tank is presented. The principle involved is explained. Several types of calorimeter that were tested are described. Measurement of the power in an ultrasonic cleaner permits: (1) comparing different ultrasonic cleaners; (2) monitoring the performance of a specific cleaner; (3) measuring the distribution of power in a cleaning tank, and (4) evaluating the effects of process variables on the power.

  13. Nanobridge SQUIDs as calorimetric inductive particle detectors

    NASA Astrophysics Data System (ADS)

    Gallop, John; Cox, David; Hao, Ling

    2015-08-01

    Superconducting transition edge sensors (TESs) have made dramatic progress since their invention some 65 years ago (Andrews et al 1949 Phys. Rev. 76 154-155 Irwin and Hilton 2005 Topics Appl. Phys. 99 63-149) until now there are major imaging arrays of TESs with as many as 7588 separate sensors. These are extensively used by astronomers for some ground-breaking observations (Hattori et al 2013 Nucl. Instrum. Methods Phys. Res. A 732 299-302). The great success of TES systems has tended to overshadow other superconducting sensor developments. However there are other types (Sobolewski et al 2003 IEEE Trans. Appl. Supercond. 13 1151-7 Hadfield 2009 Nat. Photonics 3 696-705) which are discussed in papers within this special edition of the journal. Here we describe a quite different type of detector, also applicable to single photon detection but possessing possible advantages (higher sensitivity, higher operating temperature) over the conventional TES, at least for single detectors.

  14. Theoretical Studies on Cluster Compounds

    NASA Astrophysics Data System (ADS)

    Lin, Zhenyang

    Available from UMI in association with The British Library. Requires signed TDF. The Thesis describes some theoretical studies on ligated and bare clusters. Chapter 1 gives a review of the two theoretical models, Tensor Surface Harmonic Theory (TSH) and Jellium Model, accounting for the electronic structures of ligated and bare clusters. The Polyhedral Skeletal Electron Pair Theory (PSEPT), which correlates the structures and electron counts (total number of valence electrons) of main group and transition metal ligated clusters, is briefly described. A structural jellium model is developed in Chapter 2 which accounts for the electronic structures of clusters using a crystal-field perturbation. The zero-order potential we derive is of central-field form, depends on the geometry of the cluster, and has a well-defined relationship to the full nuclear-electron potential. Qualitative arguments suggest that this potential produces different energy level orderings for clusters with a nucleus with large positive charge at the centre of the cluster. Analysis of the effects of the non-spherical perturbation on the spherical jellium shell structures leads to the conclusion that for a cluster with a closed shell electronic structure a high symmetry arrangement which is approximately or precisely close packed will be preferred. It also provides a basis for rationalising those structures of clusters with incomplete shell electronic configurations. In Chapter 3, the geometric conclusions derived in the structural jellium model are developed in more detail. The group theoretical consequences of the Tensor Surface Harmonic Theory are developed in Chapter 4 for (ML_2) _{rm n}, (ML_4) _{rm n} and (ML_5 ) _{rm n} clusters where either the xz and yz or x^2 -y^2 and xy components to L_sp{rm d}{pi } and L_sp{rm d} {delta} do not contribute equally to the bonding. The closed shell requirements for such clusters are defined and the orbital symmetry constraints pertaining to the interconversion of conformers of these clusters are described. In Chapter 5 Stone's Tensor Surface Harmonic methodology is applied to high nuclearity transition metal carbonyl cluster compounds with 13-44 metal atoms. Chapter 6 develops a new theoretical framework to account for the bonding in the high nuclearity ligated clusters with columnar topologies. In Chapter 7 the origin of non-bonding orbitals in molecular compounds is reviewed and analysed using general quantum mechanical considerations. (Abstract shortened by UMI.).

  15. High-Strength, Superelastic Compounds

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm; Noebe, Ronald; Dellacorte, Christopher; Bigelow, Glen; Thomas, Fransua

    2013-01-01

    In a previous disclosure, the use of 60- NiTiNOL, an ordered intermetallic compound composed of 60 weight percent nickel and 40 weight percent titanium, was investigated as a material for advanced aerospace bearings due to its unique combination of physical properties. Lessons learned during the development of applications for this material have led to the discovery that, with the addition of a ternary element, the resulting material can be thermally processed at a lower temperature to attain the same desirable hardness level as the original material. Processing at a lower temperature is beneficial, not only because it reduces processing costs from energy consumption, but because it also significantly reduces the possibility of quench cracking and thermal distortion, which have been problematic with the original material. A family of ternary substitutions has been identified, including Hf and Zr in various atomic percentages with varying concentrations of Ni and Ti. In the present innovation, a ternary intermetallic compound consisting of 57.6 weight percent Ni, 39.2 weight percent Ti, and 3.2 weight percent Hf (54Ni-45Ti-1Hf atomic percent) was prepared by casting. In this material, Hf substitutes for some of the Ti atoms in the material. In an alternate embodiment of the innovation, Zr, which is close in chemical behavior to Hf, is used as the substitutional element. With either substitution, the solvus temperature of the material is reduced, and lower temperatures can be used to obtain the necessary hardness values. The advantages of this innovation include the ability to solution-treat the material at a lower temperature and still achieve the required hardness for bearings (at least 50 Rockwell C) and superelastic behavior with recoverable strains greater than 2%. Most structural alloys will not return to their original shape after being deformed as little as 0.2% (a tenth of that possible with superelastic materials like 60 NiTiNOL). Because lower temperatures can be used in the heat treatment process, less energy will be consumed, and there will be less dimensional distortion and quench cracking. This results in fewer scrap parts, less material waste from large amounts of material removal, and fewer machining steps to rework parts that are out of specification. This material has a combination of properties that have been previously unobtainable. The material has a Young s modulus of approximately 95 GPa (about half that of conventional steels), moderate density (10 to 15% lower than conventional steels), excellent corrosion resistance, and high hardness (58 to 62 HRC). These properties make this material uniquely suited for advanced bearings.

  16. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2013-03-19

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  17. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2012-10-23

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  18. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2010-09-07

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  19. Bioactive compounds from marine actinomycetes.

    PubMed

    Solanki, Renu; Khanna, Monisha; Lal, Rup

    2008-12-01

    Actinomycetes are one of the most efficient groups of secondary metabolite producers and are very important from an industrial point of view. Among its various genera, Streptomyces, Saccharopolyspora, Amycolatopsis, Micromonospora and Actinoplanes are the major producers of commercially important biomolecules. Several species have been isolated and screened from the soil in the past decades. Consequently the chance of isolating a novel actinomycete strain from a terrestrial habitat, which would produce new biologically active metabolites, has reduced. The most relevant reason for discovering novel secondary metabolites is to circumvent the problem of resistant pathogens, which are no longer susceptible to the currently used drugs. Existence of actinomycetes has been reported in the hitherto untapped marine ecosystem. Marine actinomycetes are efficient producers of new secondary metabolites that show a range of biological activities including antibacterial, antifungal, anticancer, insecticidal and enzyme inhibition. Bioactive compounds from marine actinomycetes possess distinct chemical structures that may form the basis for synthesis of new drugs that could be used to combat resistant pathogens. PMID:23100742

  20. Neurodegenerations induced by organophosphorous compounds.

    PubMed

    Hargreaves, Alan J

    2012-01-01

    Organophosphorous compounds (OPs) are widely used in agriculture, industry and the home. Though best known for their acute effects when used as pesticides, which target acetylcholinesterase (AChE) activity in neuromuscular junctions and the central nervous system, not all OPs are potent inhibitors of this enzyme. The widespread use of OPs has heightened concern regarding their toxicity in man, with numerous reports linking OPs to various forms of delayed neuropathy encompassing a range of neurodegenerative, psychological and neurobehavioral effects. There is mounting evidence to suggest that sub-acute levels of OPs have the ability to interact directly with a range of target proteins in addition to AChE (i.e., noncholinergic targets), causing major disruption of membrane and protein turnover, protein phosphorylation, mitochondrial dysfunction, oxidative stress and cytoskeletal re-organisation, although the mechanisms involved are not fully understood. However, major advances have been made in the study of one OP binding protein neuropathy target esterase (NTE) in terms of its true physiological role. Additionally, there is increasing evidence for the ability of OPs to cause disruption in a number of metabolic and cell signalling pathways that affect neuronal cell proliferation, differentiation and survival and to interact direct with non-esterase proteins such as tubulin. The aim of this chapter is to review our current understanding of delayed neurotoxicity, to discuss how these molecular events may relate to each other and to suggest possible future directions in mechanistic studies of OP toxicity. PMID:22411244

  1. Superconducting compounds and alloys research

    NASA Technical Reports Server (NTRS)

    Otto, G.

    1975-01-01

    Resistivity measurements as a function of temperature were performed on alloys of the binary material system In sub(1-x) Bi sub x for x varying between 0 and 1. It was found that for all single-phase alloys (the pure elements, alpha-In, and the three intermetallic compounds) at temperatures sufficiently above the Debye-temperature, the resistivity p can be expressed as p = a sub o T(n), where a sub o and n are composition-dependent constants. The same exponential relationship can also be applied for the sub-system In-In2Bi, when the two phases are in compositional equilibrium. Superconductivity measurements on single and two-phase alloys can be explained with respect to the phase diagram. There occur three superconducting phases (alpha-In, In2Bi, and In5Bi3) with different transition temperatures in the alloying system. The magnitude of the transition temperatures for the various intermetallic phases of In-Bi is such that the disappearance or occurrence of a phase in two component alloys can be demonstrated easily by means of superconductivity measurements.

  2. Surface chemistry of organophosphorus compounds

    SciTech Connect

    Ekerdt, J.G.; Klabunde, K.J.; Shapley, J.R.; White, J.M.; Yates, J.T.

    1988-01-01

    Heterogeneous reactions currently offer one of the most favorable technological routes to the removal of air pollutants from the atmosphere. Indeed, the application of heterogeneous catalytic methods to automotive emission control represents the most-widespread exposure of the public to the benefits of catalytic technology, costing the public about $3 billion annually for all automobiles and light-duty trucks manufactured in the United States. A more-specialized area of environmental protection involves the purification of breathing air in hazardous environments such as those exposed to chemical warfare agents. Degradation of pesticides and herbicides is a related area of importance. There is a pressing need to develop reliable methods to chemically transform into harmless substances, catalytically or stoichio-metrically, a variety of types of environmental threats. This paper reviews the known decomposition chemistry of organophosphorus compounds interacting with metal and metal oxide surfaces. Three kinds of processes - oxidation, dealkylation, and hydrolysis - are known to be important, but the fundamental knowledge base in this technologically and environmentally important area is presently inadequate. Some significant research directions are identified for surface chemical science, surface reaction chemistry, solid-state synthesis, and organometallic cluster chemistry.

  3. Electroreduction of Halogenated Organic Compounds

    NASA Astrophysics Data System (ADS)

    Rondinini, Sandra; Vertova, Alberto

    The electroreductive cleavage of the carbon-halogen bond in halogenated organic compounds has been extensively studied for more than 70 years, since it is prodromal to a large variety of synthetic applications in organic electrochemistry. Over the years the research interest have progressively included the environmental applications, since several organic halocompounds are known to have (or have had) a serious environmental impact because of their (present or past) wide use as cleaning agents, herbicides, cryogenic fluids, reagents (e.g. allyl and vinyl monomers) for large production materials, etc. Recent studies have also demonstrated the wide spread out- and in-door-presence of volatile organic halides, although at low level, in connexion with residential and non-residential (e.g. stores, restaurants and transportation) activities. In this context, the detoxification of emissions to air, water and land by the selective removal of the halogen group represents a valid treatment route, which, although not leading to the complete mineralization of the pollutants, produces less harmful streams to be easily treated by electrochemical or conventional techniques. The electroreduction process is analysed and discussed in terms of electrode material, reaction medium, cell design and operation, and of substrate classification.

  4. Heterogeneous Integration of Compound Semiconductors

    NASA Astrophysics Data System (ADS)

    Moutanabbir, Oussama; Gösele, Ulrich

    2010-08-01

    The ability to tailor compound semiconductors and to integrate them onto foreign substrates can lead to superior or novel functionalities with a potential impact on various areas in electronics, optoelectronics, spintronics, biosensing, and photovoltaics. This review provides a brief description of different approaches to achieve this heterogeneous integration, with an emphasis on the ion-cut process, also known commercially as the Smart-Cut™ process. This process combines semiconductor wafer bonding and undercutting using defect engineering by light ion implantation. Bulk-quality heterostructures frequently unattainable by direct epitaxial growth can be produced, provided that a list of technical criteria is fulfilled, thus offering an additional degree of freedom in the design and fabrication of heterogeneous and flexible devices. Ion cutting is a generic process that can be employed to split and transfer fine monocrystalline layers from various crystals. Materials and engineering issues as well as our current understanding of the underlying physics involved in its application to cleaving thin layers from freestanding GaN, InP, and GaAs wafers are presented.

  5. Antiprotozoal compounds from Asparagus africanus.

    PubMed

    Oketch-Rabah, H A; Dossaji, S F; Christensen, S B; Frydenvang, K; Lemmich, E; Cornett, C; Olsen, C E; Chen, M; Kharazmi, A; Theander, T

    1997-10-01

    Two antiprotozoal compounds have been isolated from the roots of Asparagus africanus Lam. (Liliaceae), a new sapogenin, 2 beta, 12 alpha-dihydroxy-(25R)-spirosta-4,7-dien-3-one (1), which was named muzanzagenin, and the lignan (+)-nyasol (2), (Z)-(+)-4,4'-(3-ethenyl-1-propene-1,3-diyl)-bisphenol. The structure of the sapogenin was elucidated by MS and by 1D and 2D NMR methods and established by a single crystal X-ray analysis. (+)-Nyasol potently inhibits the growth of Leishmania major promastigotes, the IC50 being 12 microM, and moderately inhibits Plasmodium falciparum schizonts with the IC50 49 microM. These concentrations only moderately affect the proliferation of human lymphocytes. Muzanzagenin showed a moderate in vitro activity in all three tests, the IC50 against leishmania promastigotes was 70 microM, and against four different malaria schizont strains the IC50 values were 16, 163, 23, and 16 microM, respectively. PMID:9358645

  6. Statistical Theory of Compound-Nuclear Reactions

    SciTech Connect

    Weidenmueller, H. A.

    2008-04-17

    The Hauser-Feshbach formula for the average compound-nucleus cross section formalizes Bohr's hypothesis of the independence of formation and decay of the compound nucleus. The statistical theory of compound-nuclear reactions aims at establishing the domain and limits of applicability of that formula and of Ericson's model for statistical cross section fluctuations using random-matrix theory as a starting point. I discuss the present status of that program, including the treatment of direct reactions.

  7. Complex fragment emission from hot compound nuclei

    SciTech Connect

    Moretto, L.G.

    1986-03-01

    The experimental evidence for compound nucleus emission of complex fragments at low energies is used to interpret the emission of the same fragments at higher energies. The resulting experimental picture is that of highly excited compound nuclei formed in incomplete fusion processes which decay statistically. In particular, complex fragments appear to be produced mostly through compound nucleus decay. In the appendix a geometric-kinematic theory for incomplete fusion and the associated momentum transfer is outlined. 10 refs., 19 figs.

  8. Computed structures of polyimides model compounds

    NASA Technical Reports Server (NTRS)

    Tai, H.; Phillips, D. H.

    1990-01-01

    Using a semi-empirical approach, a computer study was made of 8 model compounds of polyimides. The compounds represent subunits from which NASA Langley Research Center has successfully synthesized polymers for aerospace high performance material application, including one of the most promising, LARC-TPI polymer. Three-dimensional graphic display as well as important molecular structure data pertaining to these 8 compounds are obtained.

  9. [Phenolic compounds from Rhododendron phaeochrysum var. agglutinatum].

    PubMed

    Sun, Ji-Qing; Lei, Chun; Hou, Ai-Jun

    2014-10-01

    Eight phenolic compounds were isolated from Rhododendron phaeochrysum var. agglutinatum and their sructures were identified as phaeochrysin (1), (2R)-4-(3',4'-dihydroxyphenyl) -2-butanol (2), (-) -rhododendrol (3), rhododendrin (4), (+) -isolariciresinol (5), (-) -lyoniresinol (6), lyoniresinol-9'-O-β-D-xylopyranoside (7), and dihydrodehydrodiconiferyl-3a-O-α-L-rhamnopyranoside (8). Compound 1 is new, and compounds 2, 5-8 were isolated from this plant for the first time. PMID:25612438

  10. Oxygen stabilized zirconium vanadium intermetallic compound

    DOEpatents

    Mendelsohn, Marshall H.; Gruen, Dieter M.

    1982-01-01

    An oxygen stabilized intermetallic compound having the formula Zr.sub.x OV.sub.y where x=0.7 to 2.0 and y=0.18 to 0.33. The compound is capable of reversibly sorbing hydrogen at temperatures from -196.degree. C. to 450.degree. C. at pressures down to 10.sup.-6 Torr. The compound is also capable of selectively sorbing hydrogen from gaseous mixtures in the presence of CO and CO.sub.2.

  11. Antibacterial and Antifungal Compounds from Marine Fungi

    PubMed Central

    Xu, Lijian; Meng, Wei; Cao, Cong; Wang, Jian; Shan, Wenjun; Wang, Qinggui

    2015-01-01

    This paper reviews 116 new compounds with antifungal or antibacterial activities as well as 169 other known antimicrobial compounds, with a specific focus on January 2010 through March 2015. Furthermore, the phylogeny of the fungi producing these antibacterial or antifungal compounds was analyzed. The new methods used to isolate marine fungi that possess antibacterial or antifungal activities as well as the relationship between structure and activity are shown in this review. PMID:26042616

  12. Hydrodesulfurization catalysis by Chevrel phase compounds

    DOEpatents

    McCarty, Kevin F.; Schrader, Glenn L.

    1985-12-24

    A process is disclosed for the hydrodesulfurization of sulfur-containing hydrocarbon fuel with reduced ternary molybdenum sulfides, known as Chevrel phase compounds. Chevrel phase compounds of the general composition M.sub.x Mo.sub.6 S.sub.8, with M being Ho, Pb, Sn, Ag, In, Cu, Fe, Ni, or Co, were found to have hydrodesulfurization activities comparable to model unpromoted and cobalt-promoted MoS.sub.2 catalysts. The most active catalysts were the "large" cation compounds (Ho, Pb, Sn), and the least active catalysts were the "small" cation compounds (Cu, Fe, Ni, Co.).

  13. Antimicrobial Action of Compounds from Marine Seaweed.

    PubMed

    Pérez, María José; Falqué, Elena; Domínguez, Herminia

    2016-03-01

    Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications. PMID:27005637

  14. Hydrodesulfurization catalyst by Chevrel phase compounds

    DOEpatents

    McCarty, K.F.; Schrader, G.L.

    1985-05-20

    A process is disclosed for the hydrodesulfurization of sulfur-containing hydrocarbon fuel with reduced ternary molybdenum sulfides, known as Chevrel phase compounds. Chevrel phase compounds of the general composition M/sub x/Mo/sub 6/S/sub 8/, with M being Ho, Pb, Sn, Ag, In, Cu, Fe, Ni, or Co, were found to have hydrodesulfurization activities comparable to model unpromoted and cobalt-promoted MoS/sub 2/ catalysts. The most active catalysts were the ''large'' cation compounds (Ho, Pb, Sn), and the least active catalysts were the ''small'' cation compounds (Cu, Fe, Ni, Co.).

  15. Pyrolysis of compounds containing polycyclic aromatic moieties

    SciTech Connect

    Javanmardian, M.; Smith, P.J.; Savage, P.E. )

    1988-06-01

    Coal is thought to exist in a complex, cross-linked, macromolecular framework in which polycyclic moieties are covalently linked together by aliphatic and heteroatomic bridges. The condensed aromatic groups can also bear peripheral, non-bridging moieties, including long aliphatic chains. The pryolysis of numerous compounds mimicking these structural features has provided considerable insight to the thermal reactions of coal. Previous pyrolyses were typically of compounds containing a single aromatic ring, which was intended to mimic the more massive condensed aromatic moieties in coal. It is possible, however, that single-ring compounds might not display the same reaction pathways and kinetics as otherwise identical compounds containing polycyclic aromatic moieties. One difference between a single aromatic ring and the condensed aromatic moieties in coal is their sizes. This difference suggests that the model-compound-derived free radicals could be considerably more mobile than their coal-derived counterparts. To probe the influence of radical mobility on pyrolysis pathways Poutsma and coworkers pyrolysed coal model compounds immobilized on silica surfaces. They found that surface immbolization can lead to an enhancement of unimolecular pathways relative to bimolecular ones. In an attempt to gain additional insight into the fundamentals of coal pyrolysis, and particularly the effects of condensed aromatics, they recently initiated experiments with compounds containing polycyclic aromatic moieties, which better represent the aromatic clusters in coal than do single-ring compounds. In this paper, the authors report on the pyrolysis of two compounds; 2-(3-phenylpropyl)-naphthalene (PPN), and 1-dodecylpyrene (DDP).

  16. Pyrolysis of compounds containing polycyclic aromatic moieties

    SciTech Connect

    Javanmardian, M.; Smith, P.J.; Savage, P.E. )

    1988-01-01

    Coal is though to exist in a complex, cross-linked, macromolecular framework in which polycyclic moieties are covalently linked together by aliphatic and heteroatomic bridges. The condensed aromatic groups can also bear peripheral, non-bridging moieties, including long aliphatic chains. The pyrolysis of numerous compounds mimicking these structural features has provided considerable insight to the thermal reactions of coal. Previous pyrolyses were typically of compounds containing a single aromatic ring, which was intended to mimic the more massive condensed aromatic moieties in coal. It is possible, however, that single-ring compounds might not display the same reaction pathways and kinetics as otherwise identical compounds containing polycyclic aromatic moieties. One difference between a single aromatic ring and the condensed aromatic moieties in coal is their sizes. This difference suggests that the model-compound-derived free radicals could be considerably more mobile than their coal-derived counterparts. To probe the influence of radical mobility on pyrolysis pathways Poutsma and coworkers pyrolyzed coal model compounds immobilized on silica surfaces. They found that surface immobilization can lead to an enhancement of unimolecular pathways relative to bimolecular ones. In an attempt to gain additional insight into the fundamentals of coal pyrolysis, and particularly the effects of condensed aromatics, the authors recently initiated experiments with compounds containing polycyclic aromatic moieties, which better represent the aromatic clusters in coal than do single-ring compounds. In this paper, they report on the pyrolysis of two compounds; 2-(3-phenylpropyl)-naphthalene (PPN), and 1-dodecylpyrene (DDP).

  17. Antimicrobial Action of Compounds from Marine Seaweed

    PubMed Central

    Pérez, María José; Falqué, Elena; Domínguez, Herminia

    2016-01-01

    Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications. PMID:27005637

  18. Automated compound classification using a chemical ontology

    PubMed Central

    2012-01-01

    Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate chemistry expert knowledge into a computer interpretable form, preventing erroneous compound assignments and allowing automatic compound classification. The automated assignment of compounds in databases, compound structure files or text documents to their related ontology classes is possible through the integration with a chemical structure search engine. As an application example, the annotation of chemical structure files with a prototypic ontology is demonstrated. PMID:23273256

  19. Spectroscopic and calorimetric investigation of short and intermediate-range structures and energetics of amorphous SiCO, SiCN, and SiBCN polymer-derived ceramics

    NASA Astrophysics Data System (ADS)

    Widgeon, Scarlett J.

    Polymer-derived ceramics (PDCs) are a new class of amorphous ceramics in the Si-B-C-N system that are synthesized by the pyrolysis of silicon-based organic polymers. PDCs are lightweight and are resistant to creep, crystallization, and oxidation at temperatures near 1800 K making them ideal for a variety of high temperature applications. In spite of being X-ray amorphous, these materials display structural heterogeneity at the nanometer length scale. Their structure and resulting properties can be drastically altered by the utilization of preceramic polymers with differing chemistry and architectures. Fundamental understanding of the atomic structure is critical in deciphering the structure-property relationships and ultimately in controlling their properties for specific engineering applications. The short-range atomic structure has been extensively investigated using a variety of techniques, however, the structures at length scales beyond next-nearest neighbors remained highly controversial. Here we report the results of a spectroscopic and calorimetric study of short and intermediate -range structure and energetic of SiOC and SiBCN PDCs derived from a wide variety of precursors. SiOC PDCs with different carbon contents were synthesized from polysiloxane precurors and their structures were studied using high-resolution 13C and 29Si nuclear magnetic resonance (NMR) spectroscopy. The results suggest that these PDCs consists of a continuous mass fractal backbone of corner-shared SiC xO4-x tetrahedral units with "voids" occupied by sp 2-hybridized graphitic carbon. The oxygen-rich SiCxO 4-x units are located at the interior of this backbone with a mass fractal dimension of ~ 2.5, while the carbon-rich units occupy the two-dimensional interface between the backbone and the free carbon nanodomains. Such fractal topology is expected to give rise to unusual mechanical and transport properties characteristic of fractal percolation networks. For example, elastic moduli and transport properties such as electrical conductivity and viscosity may show power-law dependence on composition near and above the percolation threshold of the SiOC network or that of the free-carbon phase. Si(B)CN PDCs with different carbon contents were synthesized by pyrolysis of poly(boro)silylcarbodiimides and poly(boro)silazane precursors and their structure and energetics were studied using multi-nuclear, one- and two- dimensional NMR spectroscopy and oxide melt solution calorimetry. The structure of the polysilylcarbodiimide-derived SiCN PDCs at lower carbon content and pyrolysis temperatures (800 oC) consists of amorphous nanodomains of sp2 carbon and silicon nitride with an interfacial bonding between N, C and Si atoms that is stabilized by the presence of hydrogen. The interfacial Si-C and N-C bonds are destroyed with concomitant hydrogen loss upon increasing the pyrolysis temperature to 1100 oC. Calorimetry results demonstrate that the mixed bonding in the interfacial regions play a key role in the thermodynamic stabilization of these PDCs. The size of the carbon domains increases with increasing carbon content until a continuous amorphous carbon matrix is formed with 55-60 wt % C. The polyborosilylcarbodiimide-derived SiBCN ceramics contain carbon and silicon nitride nanodomains with the BN domains being present predominantly at the interface. In contrast, the structure of the polyborosilazane-derived ceramics consists of significant amount of mixed bonding in the nearest-neighbor coordination environments of Si and B atoms leading to the formation of SiC xN4-x tetrahedral units and BCN2 triangular units. The interfacial region between the SiCN and C nanodomains is occupied by the BCN phase. These results demonstrate that the chemistry of the polymeric precursors exerts major influence on the microstructure and bonding in their derived ceramics.

  20. A[subscript 2]: Element or Compound?

    ERIC Educational Resources Information Center

    Stains, Marilyne; Talanquer, Vicente

    2007-01-01

    Particulate questions were used to investigate the strength of the mental association between the concept of compound and microscopic representations of molecules in students with different levels of chemistry preparation. The results have suggested that the mental association between the concepts of compound and particulate representations of…

  1. Perfluorinated Compounds: Emerging POPs with Potential Immunotoxicity

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been recognized as an important class of environmental contaminants commonly detected in blood samples of both wildlife and humans. These compounds have been in use for more than 60 years as surface treatment chemicals, polymerization aids, an...

  2. Hybrid Compounding in New Zealand English

    ERIC Educational Resources Information Center

    Degani, Marta; Onysko, Alexander

    2010-01-01

    This study investigates hybrid compound formation of Maori and English terms in present day New Zealand English (NZE). On the background of Maori and English language contact, the phenomenon of hybrid compounding emerges as a process that, on the one hand, symbolizes the vitality of the Maori element in NZE and, on the other hand, marks the…

  3. Crystal structure analysis of intermetallic compounds

    NASA Technical Reports Server (NTRS)

    Conner, R. A., Jr.; Downey, J. W.; Dwight, A. E.

    1968-01-01

    Study concerns crystal structures and lattice parameters for a number of new intermetallic compounds. Crystal structure data have been collected on equiatomic compounds, formed between an element of the Sc, Ti, V, or Cr group and an element of the Co or Ni group. The data, obtained by conventional methods, are presented in an easily usable tabular form.

  4. Volatile organic compound emissions from silage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a precursor to smog, emission of volatile organic compounds (VOCs) to the atmosphere is an environmental concern in some regions. The major source from farms is silage, with emissions coming from the silo face, mixing wagon, and feed bunk. The major compounds emitted are alcohols with other impor...

  5. Activities of dicationic compounds against Trichomonas vaginalis.

    PubMed

    Crowell, Andrea L; Stephens, Chad E; Kumar, Arvind; Boykin, David W; Secor, W Evan

    2004-09-01

    We evaluated 44 novel cationic compounds for activity against metronidazole-sensitive and -resistant Trichomonas vaginalis isolates. Six compounds in three different structural classes demonstrated 50% inhibitory concentrations as low as 1 microM against both sensitive and resistant isolates, suggesting a mode of action independent of parasite biochemical pathways that confer resistance to 5-nitroimidazoles. PMID:15328138

  6. Hybrid Compounding in New Zealand English

    ERIC Educational Resources Information Center

    Degani, Marta; Onysko, Alexander

    2010-01-01

    This study investigates hybrid compound formation of Maori and English terms in present day New Zealand English (NZE). On the background of Maori and English language contact, the phenomenon of hybrid compounding emerges as a process that, on the one hand, symbolizes the vitality of the Maori element in NZE and, on the other hand, marks the

  7. (CHINA) PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  8. PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  9. Improved process for synthesizing anilinosilane compounds

    NASA Technical Reports Server (NTRS)

    Dunnavant, W. R.; Markle, R. A.

    1970-01-01

    New process gives good yields of anilinosilane compounds that can be readily isolated in a high state of purity. S-collidine is used as an HCl acceptor. Silane compounds can be melt-condensed with aromatic diols to provide high molecular weight polyaryloxysilane materials that are of importance in polymer technology.

  10. A[subscript 2]: Element or Compound?

    ERIC Educational Resources Information Center

    Stains, Marilyne; Talanquer, Vicente

    2007-01-01

    Particulate questions were used to investigate the strength of the mental association between the concept of compound and microscopic representations of molecules in students with different levels of chemistry preparation. The results have suggested that the mental association between the concepts of compound and particulate representations of

  11. Heterogeneous photocatalytic reactions of sulfur aromatic compounds.

    PubMed

    Samokhvalov, Alexander

    2011-11-18

    Sulfur aromatic compounds, such as mono-, di-, tri-, and tetraalkyl-substituted thiophene, benzothiophenes, dibenzothiophenes, are the molecular components of many fossils (petroleum, oil shale, tar sands, bitumen). Structural units of natural, cross-linked heteroaromatic polymers present in brown coals, turf, and soil are similar to those of sulfur aromatic compounds. Many sulfur aromatic compounds are found in the streams of petroleum refining and upgrading (naphthas, gas oils) and in the consumer products (gasoline, diesel, jet fuels, heating fuels). Besides fossils, the structural fragments of sulfur aromatic compounds are present in molecules of certain organic semiconductors, pesticides, small molecule drugs, and in certain biomolecules present in human body (pheomelanin pigments). Photocatalysis is the frontier area of physical chemistry that studies chemical reactions initiated by absorption of photons by photocatalysts, that is, upon electronic rather than thermal activation, under "green" ambient conditions. This review provides systematization and critical review of the fundamental chemical and physicochemical information on heterogeneous photocatalysis of sulfur aromatic compounds accumulated in the last 20-30 years. Specifically, the following topics are covered: physicochemical properties of sulfur aromatic compounds, major classes of heterogeneous photocatalysts, mechanisms and reactive intermediates of photocatalytic reactions of sulfur aromatic compounds, and the selectivity of these reactions. Quantum chemical calculations of properties and structures of sulfur aromatic compounds, their reactive intermediates, and the structure of adsorption complexes formed on the surface of the photocatalysts are also discussed. PMID:21809426

  12. Interpreting Nominal Compounds for Information Retrieval.

    ERIC Educational Resources Information Center

    Gay, L. S.; Croft, W. B.

    1990-01-01

    Discusses the interpretation of nominal compounds in the context of natural language processing for information retrieval. Knowledge-intensive algorithms that can successfully interpret compounds found in technical documents are described, and experiments are reported that indicate these algorithms may be unnecessary for improving retrieval…

  13. A Cognitive Approach to English Nominal Compounds.

    ERIC Educational Resources Information Center

    Williams, Ray

    The ability of English as a second language (ESL) readers to comprehend different types of nominal compounds in English technical literature was investigated. College students were asked to recover the meaning of 73 nominal compounds in two technical English language articles on occupational health and safety. The intermediate and advanced ESL…

  14. Performance of BNL-TSTA compound cryopump

    SciTech Connect

    Hseuh, H C; Worwetz, H A

    1980-01-01

    A compound cryopump using cryocondensation pumping for hydrogen isotopes and cryosorption pumping with coconut charcoal as adsorbent for helium was designed. This compound cryopump was subsequently built (by Janis Research, Stoneham, MA) and has been tested at Brookhaven, fulfilling the design requirements and are delivered to Tritium Systems Test Assembly (TSTA) Vacuum Facility at Los Alamos Scientific Laboratory (LASL) for on-line operations.

  15. Compound Verbs in Persian: An Euphemistic Phraseology.

    ERIC Educational Resources Information Center

    Salies, Tania Gastao

    An analysis of the compound verb system of Persian marks constructions euphemistically by producing an indirect order effect and by alternating different compound and simple forms that bear the same denotation but are governed by a rigorous code of ethics. What really carries the semantic reference in these cases is the process of construing…

  16. Nitroaromatic Compounds, from Synthesis to Biodegradation

    PubMed Central

    Ju, Kou-San; Parales, Rebecca E.

    2010-01-01

    Summary: Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed. PMID:20508249

  17. Compounding pharmacies: before and after an inspection.

    PubMed

    Kulkarni, Darshan; Ricketts, Samantha

    2013-01-01

    Recent events have directed the U.S. Food and Drug Administration's attention to compounding pharmacies and have increased the frequency and vigorousness of pharmacy inspections. It is critical for compounding pharmacists to be prepared for such inspections and to understand their responsibilities after an inspection is over. PMID:24459779

  18. Amino acid modifiers in guayule rubber compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tire producers are increasingly interested in biobased materials, including rubber but also as compounding chemicals. An alternative natural rubber for tire use is produced by guayule, a woody desert shrub native to North America. Alternative compounding chemicals include naturally-occurring amino a...

  19. Interpreting Nominal Compounds for Information Retrieval.

    ERIC Educational Resources Information Center

    Gay, L. S.; Croft, W. B.

    1990-01-01

    Discusses the interpretation of nominal compounds in the context of natural language processing for information retrieval. Knowledge-intensive algorithms that can successfully interpret compounds found in technical documents are described, and experiments are reported that indicate these algorithms may be unnecessary for improving retrieval

  20. Ambient Air Monitoring for Sulfur Compounds

    ERIC Educational Resources Information Center

    Forrest, Joseph; Newman, Leonard

    1973-01-01

    A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

  1. VOLATILE ORGANIC COMPOUNDS (VOCS) CHAPTER 31.

    EPA Science Inventory

    The term "volatile organic compounds' (VOCs) was originally coined to refer, as a class, to carbon-containing chemicals that participate in photochemical reactions in the ambient (outdoor) are. The regulatory definition of VOCs used by the U.S. EPA is: Any compound of carbon, ex...

  2. Determination of repellent efficacy of natural compounds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1942, the United States Department of Agriculture (USDA) has performed repellent testing, initially for the U.S. military. In recent years, there has been a collaborative effort to evaluate a number of natural extracts and compounds for their repellent efficacy. Plant-produced compounds are u...

  3. Compound estimation procedures in reliability

    NASA Technical Reports Server (NTRS)

    Barnes, Ron

    1990-01-01

    At NASA, components and subsystems of components in the Space Shuttle and Space Station generally go through a number of redesign stages. While data on failures for various design stages are sometimes available, the classical procedures for evaluating reliability only utilize the failure data on the present design stage of the component or subsystem. Often, few or no failures have been recorded on the present design stage. Previously, Bayesian estimators for the reliability of a single component, conditioned on the failure data for the present design, were developed. These new estimators permit NASA to evaluate the reliability, even when few or no failures have been recorded. Point estimates for the latter evaluation were not possible with the classical procedures. Since different design stages of a component (or subsystem) generally have a good deal in common, the development of new statistical procedures for evaluating the reliability, which consider the entire failure record for all design stages, has great intuitive appeal. A typical subsystem consists of a number of different components and each component has evolved through a number of redesign stages. The present investigations considered compound estimation procedures and related models. Such models permit the statistical consideration of all design stages of each component and thus incorporate all the available failure data to obtain estimates for the reliability of the present version of the component (or subsystem). A number of models were considered to estimate the reliability of a component conditioned on its total failure history from two design stages. It was determined that reliability estimators for the present design stage, conditioned on the complete failure history for two design stages have lower risk than the corresponding estimators conditioned only on the most recent design failure data. Several models were explored and preliminary models involving bivariate Poisson distribution and the Consael Process (a bivariate Poisson process) were developed. Possible short comings of the models are noted. An example is given to illustrate the procedures. These investigations are ongoing with the aim of developing estimators that extend to components (and subsystems) with three or more design stages.

  4. Methods of making organic compounds by metathesis

    SciTech Connect

    Abraham, Timothy W.; Kaido, Hiroki; Lee, Choon Woo; Pederson, Richard L.; Schrodi, Yann; Tupy, Michael John

    2015-09-01

    Described are methods of making organic compounds by metathesis chemistry. The methods of the invention are particularly useful for making industrially-important organic compounds beginning with starting compositions derived from renewable feedstocks, such as natural oils. The methods make use of a cross-metathesis step with an olefin compound to produce functionalized alkene intermediates having a pre-determined double bond position. Once isolated, the functionalized alkene intermediate can be self-metathesized or cross-metathesized (e.g., with a second functionalized alkene) to produce the desired organic compound or a precursor thereto. The method may be used to make bifunctional organic compounds, such as diacids, diesters, dicarboxylate salts, acid/esters, acid/amines, acid/alcohols, acid/aldehydes, acid/ketones, acid/halides, acid/nitriles, ester/amines, ester/alcohols, ester/aldehydes, ester/ketones, ester/halides, ester/nitriles, and the like.

  5. Herbal Compounds and Toxins Modulating TRP Channels

    PubMed Central

    Vriens, Joris; Nilius, Bernd; Vennekens, Rudi

    2008-01-01

    Although the benefits are sometimes obvious, traditional or herbal medicine is regarded with skepticism, because the mechanism through which plant compounds exert their powers are largely elusive. Recent studies have shown however that many of these plant compounds interact with specific ion channels and thereby modulate the sensing mechanism of the human body. Especially members of the Transient Receptor Potential (TRP) channels have drawn large attention lately as the receptors for plant-derived compounds such as capsaicin and menthol. TRP channels constitute a large and diverse family of channel proteins that can serve as versatile sensors that allow individual cells and entire organisms to detect changes in their environment. For this family, a striking number of empirical views have turned into mechanism-based actions of natural compounds. In this review we will give an overview of herbal compounds and toxins, which modulate TRP channels. PMID:19305789

  6. Use of model compounds in coal chemistry

    SciTech Connect

    Collins, C J

    1980-01-01

    The use of model compounds in coal chemistry has been summarized. Several examples from the literature, and also from work at Oak Ridge National Laboratory have been used to illustrate the main principles involved. The current controversy on the subject of model compounds is believed to stem from a semantic misunderstanding owing to different definitions of what a model compound is. The definition of a model compound from the organic chemist's point of view is that it is a substance which may possess at least one property or structural feature suspected of being present in the sample investigated. The sample may be coal itself, a maceral, a coal-derived material or a hydrogen-donor solvent. It is stressed that a recognition of the structure-reactivity relationship in organic compounds is necessary to avoid false conclusions.

  7. Thiophenic Sulfur Compounds Released During Coal Pyrolysis.

    PubMed

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

    2013-06-01

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

  8. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

    PubMed Central

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

    2013-01-01

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

  9. Water-soluble constituents of caraway: aromatic compound, aromatic compound glucoside and glucides.

    PubMed

    Matsumura, Tetsuko; Ishikawa, Toru; Kitajima, Junichi

    2002-10-01

    From the water-soluble portion of the methanolic extract of caraway (fruit of Carum carvi L.), an aromatic compound, an aromatic compound glucoside and a glucide were isolated together with 16 known compounds. Their structures were clarified as 2-methoxy-2-(4'-hydroxyphenyl)ethanol, junipediol A 2-O-beta-D-glucopyranoside and L-fucitol, respectively. PMID:12377243

  10. Seleno-compounds in garlic and onion.

    PubMed

    Arnault, Ingrid; Auger, Jacques

    2006-04-21

    Garlic (Allium sativum) and onion (Allium cepa) are widely known for their biological properties but are far from having revealed all of their secrets even if the compounds involved in the biological mechanisms, flavenols, sulphur and seleno compounds have been identified. The beneficial effect of garlic on health including protection against cardiovascular diseases and cancers results from all of these compounds although their individual involvement is complex. Garlic and onion, broccoli, wild leek, have the ability to accumulate the selenium (Se) from soil. These Se-enriched plants present a greater protection against carcinogenesis than the common plants and two Se-compounds possessing anti-cancer activity have been identified: Se-methyl selenocysteine and gamma-glutamyl-Se-methyl selenocysteine. However, several Se-compounds from Se-enriched garlic or onion remain unidentified. The techniques for the detection of Se-species are numerous but few methods are able to identify the detected compounds. The very small quantities of Se-compounds present and the clear lack of standards do not make their analysis straightforward, particularly for non-enriched samples. Over the last 10 or so years development of the synthesis of Se-compounds and the use of GC-AED or EC/HPLC-ICP-MS have shown considerable possibilities. These techniques have allowed advances in the identification of Se-compounds, some of which are analogues of S-compounds in plants and yeasts. When these techniques are coupled to EC/HPLC-APCI-MS-MS, they provide a lot of information about the Se-biosynthesis in garlic. This has allowed the preferential formation of methylated compounds in Se-biochemistry to be identified, in contrast to the sulphur biochemistry of the Allium spp. in which compounds containing propenylic groups predominate. This review focuses on the recent advances in the analytical methods of Se-compounds in garlic and onion and particular attention is given to the biological properties of Se-species identified in Se-enriched plants. PMID:16480995

  11. Coordination Compounds of Transition Metals in the Chemistry of Aromatic Nitro-compounds

    NASA Astrophysics Data System (ADS)

    Izakovich, E. N.; Khidekel', M. L.

    1988-05-01

    The catalytic possibilities of coordination compounds of transition metals in the chemistry of aromatic nitro-compounds are discussed. The catalytic (including enzymic) reduction of aromatic nitro-compounds by various reductants, namely molecular hydrogen, alkali metal tetrahydroborates, CO + H2O and CO + H2 mixtures, alcohols, secondary amines, etc., is considered. The interaction of aromatic nitro-compounds with transition metal complexes, leading either to complexes containing the aromatic nitro-compound or to reduction products, is discussed. The structures of these complexes are classified. The bibliography includes 236 references.

  12. Environmental exposure to preformed nitroso compounds.

    PubMed

    Tricker, A R; Spiegelhalder, B; Preussmann, R

    1989-01-01

    In the human environment, nitrosatable amine precursors to N-nitroso compounds and nitrosating species such as nitrite and oxides of nitrogen are abundant. As a result, the formation of N-nitroso compounds and human exposure to these compounds show a rather complex pattern. The largest known human exposures to exogenous N-nitrosamines occur in the work place. This is particularly evident in the rubber and tyre manufacturing industry and in metal cutting and grinding shops. Nearly all industries which are concerned with the production and/or use of amines have a related nitrosamine problem. Outside the industrial environment, commodities such as cosmetics, pharmaceuticals, rubber and household products, which are either prepared from amines or contain high concentrations of amino compounds, may be subject to contamination by low concentrations of N-nitroso compounds. This contamination may result from the use of contaminated starting materials, in particular amines, or from the formation of N-nitroso compounds during manufacturing processes. A similar problem exists with agricultural chemicals. As our knowledge of the occurrence and formation of N-nitroso compounds in the environment increases, preventive measures can be introduced, particularly in manufacturing industries, to reduce the levels of human exposure to nitrosamines in the work place and to protect the consumer from nitrosamine exposure from household commodities. PMID:2696580

  13. Taste + odor interactions in compound aversion conditioning.

    PubMed

    Trost, Christina A; Batsell, W Robert

    2004-11-01

    In three experiments with rats, taste + odor interactions in compound aversion conditioning were investigated. In Experiment 1, two odors (0.02% almond and 0.02% orange) were compared on single-element odor aversions, taste (denatonium) potentiated odor aversions, and potentiated odor aversions following taste extinction. Although no odor differences were seen following single-element conditioning, both types of potentiated orange odor aversions were stronger than their almond odor counterparts. These data show that odors of similar conditionability are differentially potentiated by the same taste. To determine whether these differences were due to unique perceptual representations, the effects of elemental extinction or compound extinction on aversions to the compound were investigated in Experiments 2 and 3. In Experiment 2, orange odor extinction weakened responding to the compound significantly more than taste extinction did. In contrast, almond odor extinction and taste extinction produced similar decrements in responding to the compound in Experiment 3. These results suggest that the perceptual representation of these specific taste + odor compounds are different, and they are discussed in regard to configural and within-compound association accounts of potentiation. PMID:15825885

  14. Biodegradable compounds: Rheological, mechanical and thermal properties

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  15. Aroma compounds in sweet whey powder.

    PubMed

    Mahajan, S S; Goddik, L; Qian, M C

    2004-12-01

    Aroma compounds in sweet whey powder were investigated in this study. Volatiles were isolated by solvent extraction followed by solvent-assisted flavor evaporation. Fractionation was used to separate acidic from nonacidic volatiles. Gas chromatography/mass spectrometry and gas chromatography/olfactometry were used for the identification of aroma compounds. Osme methodology was applied to assess the relative importance of each aroma compound. The most aroma-intense free fatty acids detected were acetic, propanoic, butanoic, hexanoic, heptanoic, octanoic, decanoic, dodecanoic, and 9-decenoic acids. The most aroma-intense nonacidic compounds detected were hexanal, heptanal, nonanal, phenylacetaldehyde, 1-octen-3-one, methional, 2,6-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3-dimethylpyrazine, 2,3,5-trimethylpyrazine, furfuryl alcohol, p-cresol, 2-acetylpyrrole, maltol, furaneol, and several lactones. This study suggested that the aroma of whey powder could comprise compounds originating from milk, compounds generated by the starter culture during cheese making, and compounds formed during the manufacturing process of whey powder. PMID:15545366

  16. Distributed imaging using compound eye sensors

    NASA Astrophysics Data System (ADS)

    Carr, Peter K.; Ara, Farhana; Thomas, Paul J.; Hornsey, Richard I.

    2004-10-01

    The capture of a wide field of view (FOV) scene by dividing it into multiple sub-images is a technique with many precedents in the natural world, the most familiar being the compound eyes of insects and arthropods. Artificial structures of networked cameras and simple compound eyes have been constructed for applications in robotics and machine vision. Previous work in this laboratory has explored the construction and calibration of sensors which produce multiple small images (of ~150 pixels in diameter) for high-speed object tracking. In this paper design options are presented for electronic compound eyes consisting of 101 - 103 identical 'eyelets'. To implement a compound eye, multiple sub-images can be captured by distributing cameras and/or image collection optics. Figures of merit for comparisons will be developed to illustrate the impact of design choices on the field of view, resolution, information rate, image processing, calibration, environmental sensitivity and compatibility with integrated CMOS imagers. Whereas compound eyes in nature are outward-looking, the methodology and subsystems for an outward-looking compound-eye sensor are similar for in an inward-looking sensor, although inward-looking sensors have a common region viewable to all eyelets simultaneously. The paper addresses the design considerations for compound eyes in both outward-looking and inward-looking configurations.

  17. Risk and liabilities of prescribing compounded medications.

    PubMed

    Randell, Michael D; Duffy, Phillip J

    2014-07-01

    Complications resulting from the use of compounded medications have become a troubling trend nationwide. There is a significant potential for patients to suffer serious harm from the use of substandard medications prepared by compounding pharmacies, and the reality of this problem has been demonstrated in several well-publicized incidences of serious medical complications, including patient deaths, that directly resulted from the use of medications prepared at compounding pharmacies. Unlike US Food and Drug Administration (FDA)-approved drugs, compounded products are not required to meet evidentiary standards for establishing safety and efficacy. Moreover, these products are not held to Good Manufacturing Practices, which require regular inspections, quality control testing, and rejection of material not meeting specifications. Physicians, as well as other prescribers, need to be aware that when a patient suffers harm from using a compounded medication, those injured patients may bring negligence and malpractice claims, not only against the pharmacy and the pharmacist responsible for preparing the medication, but also against the prescribing physician and the physician’s practice. Consequently, the best way for physicians to manage professional risk and avoid both litigation and potential negative patient outcomes related to compounded pharmaceuticals is to not use these products if there is an FDA-approved product available. However, if the use of a compounded medication is medically necessary, then physicians should adhere to the FDA guidance concerning traditional compounding. Moreover, it would be prudent for any physician who intends to either resell or participate in the distribution of compounded products beyond the direct treatment of their patients to consider obtaining the appropriate insurance coverage for this activity. PMID:25276868

  18. Varieties of compound terms and their treatment

    SciTech Connect

    Strehlow, R.A.

    1982-01-01

    Compound term's are essential in technical terminologies, because of the need to distinguish precisely between subtle or detailed differences in concepts or things. Compound terms of different sorts require different approaches in defining and in handling. Unitary compound terms, those consisting of a base word and one or more affixes, are common in non-technical usage; but are generated in technical terminological work by drawing from a greater number of less common affixes. Still, multiple meanings for the affixes are common. As in the case of ordinary usage, some affixes are independent enough so that the affix may be defined, but the compound term doesn't require definition. Indexing may require cross referencing in some cases. Compound terms consisting of more than one word are common in most technical fields. These terms may be classified as one of three types; sentential, hierarchic, or categoric. Sentential compound terms are descriptive and incidental, e.g., two-inch stirred chemical reactor. Such terms rarely require definition and would usually be further described in the context of the terms usage. Hierarchic compound terms form a mini-classification and may actually be precursors of elements of a formal classification. These terms require definition when the implied classification is essential, but not formalized. In this case a vocabulary or terminology provides a convenient display of part of a larger classification. Categoric compound terms, terms of several words listing essential, non-incidental aspects of the concept or entity may be viewed as a faceted (non-hierarchic) classification. The style of definition and the indexing of technical terms may be most efficiently approached with a knowledge of the varieties of compound terms.

  19. [Common features of antibacterial compounds: an analysis of 104 compounds library].

    PubMed

    Veselov, M S; Sergiev, P V; Osterman, I A; Skvortsov, D A; Golovina, A Ya; Andreyanova, E S; Laptev, I G; Pletnev, P I; Evfratov, S A; Marusich, E I; Leonov, S V; Ivanenkov, Ya A; Bogdanov, A A; Dontsova, O A

    2015-01-01

    Antibacterial compounds are one of the essential classes of clinically important drugs. High throughput screening allowed revealing potential antibiotics active towards any molecular target in bacterial cell. We used a library of 9820 organic compounds with highly diversified structures to screen for antibacterial activity. As the result of automated screening, 103 compounds were found to possess antibacterial activity against Escherichia coli. The properties of these compounds were compared with those of initial library. Non-linear Kohonen mapping was used to analyze the differences between non-active molecules from initial library, identified antibacterial hits and compounds with reported antibacterial activity. It was found that identified antibacterial compounds are located in the separated area of chemical space. It can be therefore suggested that these molecules belong to novel classes of antibacterial compounds and could be studied further. PMID:26716754

  20. Application of bicyclic and cage compounds

    NASA Technical Reports Server (NTRS)

    Clark, R. D.; Archuleta, B. S.

    1976-01-01

    The results of a literature survey of the field of bicyclic and cage compounds were presented, with the objective of identifying those types of compounds with unusual physical and chemical stability, and determining what practical applications have been found for these compounds. Major applications have been as polymers, polymer additives, medicinals, and pesticides. Lesser applications have included fuels, fuel additives, lubricants, lubricant additives, and perfumes. Several areas where further work might be useful were also outlined; these are primarily in the areas of polymers, polymer additives, medicinals, and synthetic lubricants.

  1. Natural compounds with Wnt signal modulating activity.

    PubMed

    Fuentes, Rolly G; Arai, Midori A; Ishibashi, Masami

    2015-12-19

    Covering: up to 2015 The Wnt signalling pathway is essential in many biological processes. The Wnt signal is associated with several diseases, particularly cancer and neurodegenerative diseases. Recently, high-throughput screening systems have been developed to rapidly identify compounds, including natural compounds, that target the Wnt signal. Some studies on natural modulators of the Wnt signal have also suggested their possible target. This review highlights some important natural compounds reported to regulate Wnt activity and describes their possible mechanism of action. PMID:26395516

  2. Compound leaf development in model plant species.

    PubMed

    Bar, Maya; Ori, Naomi

    2015-02-01

    Plant leaves develop in accordance with a common basic program, which is flexibly adjusted to the species, developmental stage and environment. Two key stages of leaf development are morphogenesis and differentiation. In the case of compound leaves, the morphogenesis stage is prolonged as compared to simple leaves, allowing for the initiation of leaflets. Here, we review recent advances in the understanding of how plant hormones and transcriptional regulators modulate compound leaf development, yielding a substantial diversity of leaf forms, focusing on four model compound leaf organisms: cardamine (Cardamine hirsuta), tomato (Solanum lycopersicum), medicago (Medicago truncatula) and pea (Pisum sativum). PMID:25449728

  3. Microbial production of scent and flavor compounds.

    PubMed

    Carroll, Austin L; Desai, Shuchi H; Atsumi, Shota

    2016-02-01

    Scents and flavors like those of fresh oranges are no longer limited to just the natural product. Fruit, flower, and essential oil scents have found place in cosmetics, soaps, candles, and food amongst many common household products. With their increasing global demand and difficulty in extractation from the natural source, alternative methods of their production are being sought. One sustainable method is to employ microorganisms for the production of these high value compounds. With the tools of metabolic engineering, microorganisms can be modified to produce compounds such as esters, terpenoids, aldehydes, and methyl ketones. Approaches and challenges for the production of these compounds from microbial hosts are discussed in this review. PMID:26426958

  4. Bioremediation of nitroaromatic and haloaromatic compounds

    SciTech Connect

    Alleman, B.C.; Leeson, A.

    1999-10-01

    Sites contaminated with explosive compounds, pesticides, herbicides, PCBs, and other aromatic compounds present formidable technical, regulatory, and financial challenges. The application of bioremediation technologies at such sites offers the promise of cost-effective site remediation that can serve as a key component of a well-formulated strategy for achieving site closure. This volume presents the results of bench-, pilot-, and field-scale projects focused on the use of biological approaches to remediate problem compounds, such as RDX, HMX, TNT, DDT, 2,4-D, nitro- and chlorobenzenes, nitroaniline, chloroaniline, hexachlorobenzene, PCPs, PCBs, and dichlorophenol in soils and groundwater.

  5. Bioremediation of nitroaromatic and haloaromatic compounds

    SciTech Connect

    Alleman, B.C.; Leeson, A.

    1999-11-01

    Sites contaminated with explosive compounds, pesticides, herbicides, PCBs, and other aromatic compounds present formidable technical, regulatory, and financial challenges. The application of bioremediatin technologies at such sites offers the promise of cost-effective site remediation that can serve as a key component of a well-formulated strategy for achieving site closure. This volume presents the results of bench-, pilot-, and field-scale projects focused on the use of biological approaches to remediate problem compounds, such as RDX, HMX, TNT, DDT, 2,4-D, nitro- and chlorobenzenes, nitroaniline, chloroaniline, hexachlorbenzene, PCPs, PCBs, and dichlorophenol in soils and groundwater.

  6. Bioremediation of nitroaromatic and haloaromatic compounds

    SciTech Connect

    Alleman, B.C.; Leeson, A.

    1999-01-01

    Sites contaminated with explosive compounds, pesticides, herbicides, PCBs, and other aromatic compounds present formidable technical, regulatory, and financial challenges. The application of bioremediatin technologies at such sites offers the promise of cost-effective site remediation that can serve as a key component of a well-formulated strategy for achieving site closure. This volume presents the results of bench-, pilot-, and field-scale projects focused on the use of biological approaches to remediate problem compounds, such as RDX, HMX, TNT, DDT, 2,4-D, nitro- and chlorobenzenes, nitroaniline, chloroaniline, hexachlorbenzene, PCPs, PCBs, and dichlorophenol in soils and groundwater.

  7. Chlorinated organic compounds produced by Fusarium graminearum.

    PubMed

    Ntushelo, Khayalethu

    2016-06-01

    Fusarium graminearum, a pathogen of wheat and maize, not only reduces grain yield and degrades quality but also produces mycotoxins in the infected grain. Focus has been on mycotoxins because of the human and animal health hazards associated with them. In addition to work done on mycotoxins, chemical profiling of F. graminearum to identify other compounds produced by this fungus remains critical. With chemical profiling of F. graminearum the entire chemistry of this fungus can be understood. The focus of this work was to identify chlorinated compounds produced by F. graminearum. Various chlorinated compounds were detected and their role in F. graminearum is yet to be understood. PMID:27165533

  8. A growing codependency: compounding pharmacy and safety.

    PubMed

    Prince, Bryan; Lundevall, Jeremy

    2013-01-01

    Pharmacists and pharmacy technicians are in constant contact with potent compounds. When compounding with powders, there is a susceptibility to environmental conditions such that proper containment be in place to keep the employees safe, the medicine free from cross contamination or the introduction of outside contaminants, and the workplace free from floating active pharmaceutical ingredient particles. Adapting powder hoods as safety devices that work in direct relation to clearly defined standard operating procedures and good lab practices will facilitate a safer lab environment for employees and ensure good-quality prescriptions. This article discusses the safety concerns of compounding with powders and the safety measures to consider when purchasing powder hoods. PMID:24579299

  9. Food applications of natural antimicrobial compounds

    PubMed Central

    Lucera, Annalisa; Costa, Cristina; Conte, Amalia; Del Nobile, Matteo A.

    2012-01-01

    In agreement with the current trend of giving value to natural and renewable resources, the use of natural antimicrobial compounds, particularly in food and biomedical applications, becomes very frequent. The direct addition of natural compounds to food is the most common method of application, even if numerous efforts have been made to find alternative solutions to the aim of avoiding undesirable inactivation. Dipping, spraying, and coating treatment of food with active solutions are currently applied to product prior to packaging as valid options. The aim of the current work is to give an overview on the use of natural compounds in food sector. In particular, the review will gather numerous case-studies of meat, fish, dairy products, minimally processed fruit and vegetables, and cereal-based products where these compounds found application. PMID:23060862

  10. Dimerization of Aromatic C-Nitroso Compounds.

    PubMed

    Beaudoin, Daniel; Wuest, James D

    2016-01-13

    Aromatic C-nitroso compounds (Ar-N═O) and related species have a rich chemical history, and they continue to interest researchers in many fields. Among the most distinctive and puzzling properties of these compounds is their ability to dimerize reversibly to form azodioxy compounds. The present review subjects this intriguing phenomenon to comprehensive analysis. All aspects of the subject are examined in detail, including the structures of monomeric and dimeric forms, the mechanism of dimerization, features that favor or disfavor dimerization, thermodynamic and kinetic factors, dimerization under specific conditions (including in solution, in the solid state, and on surfaces), and the special associative behavior of dinitroso and polynitroso compounds. By summarizing the current state of knowledge, the review promises to spur further advances in the evergreen field of C-nitroso chemistry, including the discovery of new ways to exploit the reversible dimerization of nitrosoarenes. PMID:26730505

  11. The Industrial Reduction of Aromatic Nitro Compounds.

    ERIC Educational Resources Information Center

    Gilbert, G.

    1980-01-01

    Describes methods for enriching an A-level chemistry course with a series of chemical company visits. The rationale is discussed for an emphasis of the visits on the industrial reduction of aromatic nitro compounds. (CS)

  12. Application of Fiber Optics and Compound Collectors

    NASA Technical Reports Server (NTRS)

    Fantone, S. D.

    1984-01-01

    The utilization of fiber optics and compound flux collectors as optical components in stellar photometers is discussed. Basic principles are outlined for such components and systems issues are addressed.

  13. Agricultural Compounds in Water and Birth Defects.

    PubMed

    Brender, Jean D; Weyer, Peter J

    2016-06-01

    Agricultural compounds have been detected in drinking water, some of which are teratogens in animal models. The most commonly detected agricultural compounds in drinking water include nitrate, atrazine, and desethylatrazine. Arsenic can also be an agricultural contaminant, although arsenic often originates from geologic sources. Nitrate has been the most studied agricultural compound in relation to prenatal exposure and birth defects. In several case-control studies published since 2000, women giving birth to babies with neural tube defects, oral clefts, and limb deficiencies were more likely than control mothers to be exposed to higher concentrations of drinking water nitrate during pregnancy. Higher concentrations of atrazine in drinking water have been associated with abdominal defects, gastroschisis, and other defects. Elevated arsenic in drinking water has also been associated with birth defects. Since these compounds often occur as mixtures, it is suggested that future research focus on the impact of mixtures, such as nitrate and atrazine, on birth defects. PMID:27007730

  14. BEHAVIORAL TOXICITY OF TRIALKYLTIN COMPOUNDS: A REVIEW

    EPA Science Inventory

    Triethyltin (TET) and trimethyltin (TMT) are neurotoxic organotin compounds which produce different patterns of toxicity in adult animals. Exposure to TET produces behavioral toxicity (decreased motor activity, grip strength, operant response rate and startle response amplitude) ...

  15. Botanical Compounds: Effects on Major Eye Diseases

    PubMed Central

    Huynh, Tuan-Phat; Mann, Shivani N.; Mandal, Nawajes A.

    2013-01-01

    Botanical compounds have been widely used throughout history as cures for various diseases and ailments. Many of these compounds exhibit strong antioxidative, anti-inflammatory, and antiapoptotic properties. These are also common damaging mechanisms apparent in several ocular diseases, including age-related macular degeneration (AMD), glaucoma, diabetic retinopathy, cataract, and retinitis pigmentosa. In recent years, there have been many epidemiological and clinical studies that have demonstrated the beneficial effects of plant-derived compounds, such as curcumin, lutein and zeaxanthin, danshen, ginseng, and many more, on these ocular pathologies. Studies in cell cultures and animal models showed promising results for their uses in eye diseases. While there are many apparent significant correlations, further investigation is needed to uncover the mechanistic pathways of these botanical compounds in order to reach widespread pharmaceutical use and provide noninvasive alternatives for prevention and treatments of the major eye diseases. PMID:23843879

  16. MOLECULAR BASIS OF BIODEGRADATION OF CHLOROAROMATIC COMPOUNDS

    EPA Science Inventory

    Chlorinated aromatic hydrocarbons are widely used in industry and agriculture and comprise the bulk of environmental pollutants. lthough simple aromatic compounds are biodegradable by a variety of degradative pathways, their halogenated counterparts are more resistant to bacteria...

  17. MOLECULAR BASIS OF BIODEGRADATION OF CHLOROAROMATIC COMPOUNDS

    EPA Science Inventory

    Chlorinated aromatic hydrocarbons are widely used in industry and agriculture, and comprise the bulk of environmental pollutants. Although simple aromatic compounds are biodegradable by a variety of degradative pathways, their halogenated counterparts are more resistant to bacter...

  18. Perfluorinated Compounds In The Ohio River Basin

    EPA Science Inventory

    Contaminants of emerging concern (CECs) in waterways include pharmaceuticals and personal care products (PPCPs), alkylphenols, endocrine disrupting chemicals (EDCs) and perfluorinated alkyl compounds (PFCs). Their distributions and persistence in the aquatic environment remain p...

  19. HEALTH EFFECTS ASSESSMENT FOR TIN AND COMPOUNDS

    EPA Science Inventory

    The report summarizes and evaluates information relevant to a preliminary interim assessment of adverse health effects associated with specific chemicals or compounds. The Office of Emergency and Remedial Response (Superfund) uses these documents in preparing cost-benefit analyse...

  20. Production method for making rare earth compounds

    DOEpatents

    McCallum, R. William; Ellis, Timothy W.; Dennis, Kevin W.; Hofer, Robert J.; Branagan, Daniel J.

    1997-11-25

    A method of making a rare earth compound, such as a earth-transition metal permanent magnet compound, without the need for producing rare earth metal as a process step, comprises carbothermically reacting a rare earth oxide to form a rare earth carbide and heating the rare earth carbide, a compound-forming reactant (e.g. a transition metal and optional boron), and a carbide-forming element (e.g. a refractory metal) that forms a carbide that is more thermodynamically favorable than the rare earth carbide whereby the rare earth compound (e.g. Nd.sub.2 Fe.sub.14 B or LaNi.sub.5) and a carbide of the carbide-forming element are formed.