Note: This page contains sample records for the topic xvi calorimetric determination from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
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 UOâ(OH)â · HâO (schoepite)  

Microsoft Academic Search

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, UOâ(OH)â · HâO. The following results have been obtained at the standard reference temperature T = 298.15 K:standard molar enthalpy of formation Î\\/sub f\\/H\\/sub m\\/°(T) = -1825.4 +-

I. R. Tasker; B. M. Lewis; G. K. Johnson; E. H. P. Cordfunke

1987-01-01

2

A calorimetric method to determine water activity.  

PubMed

A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg(-1) to 3 mol kg(-1) and seven saturated aqueous salt solutions (LiCl, MgCl(2), NaBr, NaCl, KCl, KNO(3), and K(2)SO(4)) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities. PMID:22129000

Björklund, Sebastian; Wadsö, Lars

2011-11-01

3

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

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.

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

1987-08-01

4

Calorimetric Determination of Aqueous Ion Enthalpies  

NASA Astrophysics Data System (ADS)

Enthalpies of formation of aqueous ions can be determined by solution calorimetry. This article describes an experiment for the physical chemistry laboratory. Enthalpies of formation of aqueous sodium, potassium, chloride and iodide ions are calculated from the enthalpies of solution of salts. The enthalpies of solution are measured with the Parr 1455 solution calorimeter. The calorimeter is controlled and data are collected by a computer attached to the calorimeter's serial port. The experiment is simple and yields results that are in good agreement with literature values.

Siders, Paul

1997-02-01

5

Calorimetric determination of the enthalpy of formation for pyrophyllite  

NASA Astrophysics Data System (ADS)

A calorimetric study of the natural pyrophyllite was performed by high-temperature melt calorimetry on a Tian-Calvet calorimeter. Based on experimentally determined in this work for pyrophyllite and gibbsite, as well as previously obtained for corundum and quartz, the total value of the enthalpy increment for the sample heated from room temperature to 973 K and the enthalpy of dissolution at 973 K by Hess's law, the enthalpy of formation of pyrophyllite of Al2[(OH)2/Si4O10] composed of elements was calculated at 298.15 K: ?f H {el/o}(298.15 K) = -5639.8 ± 5.7 kJ/mol.

Ogorodova, L. P.; Kiseleva, I. A.; Mel'Chakova, L. V.; Vigasina, M. F.; Spiridonov, E. M.

2011-09-01

6

Calorimetric determination of the enzyme activity immobilised on macroporous glass membranes  

Microsoft Academic Search

A direct method for the determination of the catalytic activity of immobilised enzymes by use of a miniaturised calorimeter is presented. The possibilities and advantages of the calorimetric method are demonstrated by investigations with catalase immobilised on macroporous glass membranes as model enzyme. The investigated enzyme carrier systems are characterised by a high catalytic activity, a marked long-term stability and

Hagen Graebner; Regina Hüttl; Gert Wolf

2002-01-01

7

Calorimetric determination of enthalpies of lysozyme folding at a liquid-solid interface  

Microsoft Academic Search

Summary  Calorimetric determination of the total enthalpy changes (?Hi) of guanidine-denatured lysozyme (Lys) during the adsorption with simultaneously refolding on the surface of hydrophobic\\u000a interaction chromatography packings was carried out at 250.001C. The measured ?Hiin the circumstances should include the changes in the three fractions: adsorption, dehydration and molecular conformation.\\u000a It was found that when the unfolded Lys molecules are adsorbed

X. P. Geng; H. F. Zhang; B. H. Wang; X. D. Geng; J. W. Xing

2005-01-01

8

Calorimetric Determinations of the Heat and Products of Detonation for Explosives: October 1961 to April 1982  

NASA Astrophysics Data System (ADS)

This report is a compilation of heat-of-detonation and product-composition data obtained at Lawrence Livermore National Laboratory during the last 21 years. In each determination, a 25-g high-explosive charge was detonated in a bomb calorimeter; a complete calorimetric measurement was made in 1 to 2 h with a precision of 0.3%. Data were interpreted using thermodynamic and hydrodynamic computer calculations. For unconfined or lightly confined charges, the released energy is largely retained in the products, which are subsequently shocked considerably off the Chapman-Jouguet isentrope by reflections from the bomb wall. For heavily confined charges, the detonation energy is largely converted to kinetic and internal energy of the confining case, and the products expand with minimal reshock along the Chapman-Jouguet isentrope.

Ornellas, D. L.

1982-04-01

9

Pope Benedict XVI's \\  

Microsoft Academic Search

“Business ethics risks becoming subservient to existing economic and financial systems rather than correcting their dysfunctional aspects.” This statement from Pope Benedict XVI’s Encyclical letter \\

Stormes James R S. J

2010-01-01

10

Calorimetric monitoring of lyophilization.  

PubMed

This paper describes an apparatus and method for monitoring the lyophilization of a formulation by using calorimetric measurements. From calorimetric measurements, the energy transferred during each phase of the process can be determined. A brief review of the existing monitoring methods shows that they possess no direct relationship to the thermal energy that represents the real driving force for the lyophilization process. A general description of the apparatus is presented with special emphasis made on the sensor construction and calibration. The means for determining the heat transfer rate (Qm) and total energy (Hm) for each step of the process are described. The use of calorimetric measurements are demonstrated by showing actual thermographs of freezing, primary drying and secondary drying processes for several formulations. Some key advantages of calorimetric monitoring of the lyophilization process are demonstrated by accurately determining the completion of the primary drying and detection of exothermic reactions during the secondary drying. PMID:8581458

Jennings, T A; Duan, H

11

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

SciTech Connect

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.

Leigh R. Martin; Peter R. Zalupski

2011-06-01

12

BENEDICT XVI: PEACEMAKER  

Microsoft Academic Search

Pope Benedict XVI has had unexpected success as a religious diplomat, advocating for peace between Christians and Muslims. Despite offending the Muslim community in a speech given during his first year as Pope, he has since taken great steps towardsreconciliation. At a public appearance in Turkey in 2007, Pope Benedict and Muslims leaders emphasized the commonalities between their religions in

Drew Christiansen S. J

2007-01-01

13

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

PubMed Central

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.

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

1991-01-01

14

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

SciTech Connect

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.

Casas, L. M. [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain); Plantier, F.; Bessieres, D. [Laboratoire de Thermodynamique et Energetique des Fluides Complexes-UMR 5150, Universite de Pau et des Pays de l'Adour, BP 1155, 64013 Pau (France)

2009-12-15

15

Quantitative differential scanning calorimetric analysis for determining total polar compounds in heated oils  

Microsoft Academic Search

A new differential scanning calorimetry (DSC) method was developed for the determination of total polar compounds (TPC) in\\u000a heated oils. Three different types of edible oils, refined, bleached, and deodorized corn oil (CO), palm olein (RBDPO), and\\u000a soybean oil (SO), were used in this study, Each type of edible oil was heated at 180°C in a deep fryer to obtain

C. P. Tan; Y. B. Che Man

1999-01-01

16

Calorimetric Determination of Energy Levels in Rare-Earth and Yttrium-Iron Garnets  

Microsoft Academic Search

It is shown that low-temperature calorimetry can be a sensitive method for determining the lowest excited energy levels in the rare-earth iron garnets. From Pauthenet's magnetization data one expects the lowest excited levels of several rare-earth ions to become populated at temperatures well below 20°K and to contribute a large specific heat. This property offers the possibility of testing the

A. Brooks Harris; Horst Meyer

1962-01-01

17

Approaches to determine the enthalpy of crystallisation, and amorphous content, of lactose from isothermal calorimetric data.  

PubMed

Amorphous lactose will crystallise rapidly if its glass transition temperature is reduced below its storage temperature. This is readily achieved by storing samples at ambient temperature and a relative humidity (RH) of greater than 50%. If the sample is monitored in an isothermal microcalorimeter as it crystallises, the heat changes associated with the event can be measured; indeed this is one of the methods used to quantify the amorphous content of powders and formulations. However, variations in the calculation methods used to determine these heat changes have led to discrepancies in the values reported in the literature and frequently make comparison of data from different sources difficult. Data analysis and peak integration software allow the selection and integration of specific areas of complex traces with great reproducibility; this has led to the observation that previously ignored artefacts are in fact of sufficient magnitude to affect calculated enthalpies. In this work a number of integration methodologies have been applied to the analysis of amorphous spray-dried lactose, crystallised under 53 or 75% RH at 25 degrees C. The data allowed the selection of a standard methodology from which reproducible heat changes could be determined. The method was subsequently applied to the analysis of partially amorphous lactose samples (containing 1-100% (w/w) amorphous content) allowing the quantification limit of the technique to be established. It was found that the best approach for obtaining reproducible results was (i) to crystallise under an RH of 53%, because this slowed the crystallisation response allowing better experimental measurement and (ii) to integrate all the events occurring in the ampoule, rather than trying to select only that region corresponding to crystallisation, since it became clear that the processes occurring in the cell overlapped and could not be deconvoluted. The technique was able to detect amorphous contents as low as 1% (w/w), using this integration strategy, although it was observed that the calibration plot constructed showed a negative deviation from linearity. It is suggested that such non-ideal behaviour results from the formation of varying ratios of alpha-lactose monohydrate, anhydrous alpha-lactose and anhydrous beta-lactose. PMID:15454300

Dilworth, Sarah E; Buckton, Graham; Gaisford, Simon; Ramos, Rita

2004-10-13

18

Calorimetric properties of magmas  

NASA Astrophysics Data System (ADS)

Magmatic and volcanic processes are strongly controlled by the physical and thermodynamic properties of silicate melts. Recently it has been recognized that the way in which the magma crosses the so-called "glass transition" boundary can determine whether a quite degassing, through preferential pathways, or a catastrophic eruption will take place. On the other hand, the thermodynamic properties inform us regarding the internal energy of melts and crystals and how internal energy and other closely related thermodynamic functions change with temperature, so affecting processes as partial melting, solidification, the advective transport of heat, and volatile exsolution and degassing. The effect of volatiles on these properties is well recognized, but not satisfactorily investigated so far. In this study, calorimetric measurements were conducted on four series of variously hydrated multicomponent melts, obtained by remelting and homogeneization of natural magmas in order to investigate the effect of water on the glass transition interval (Tg) and heat capacity (Cp). The hydrous samples were synthesized in a piston cylinder and measured by the employement of a differential scanning calorimeter (DSC). Pantelleritic, latitic, HK basaltic and trachybasaltic compositions have been analysed over a range of water contents up to 5.3 wt%.For each investigated melt composition the cooling rate dependence of Tg has been characterized at four different temperatures corresponding to the onset, the inflection point, the peak and the stable liquid regions of the heat capacity curves. Tg of all compositions are strongly reduced by increasing water content. Base composition also has an effect, with the lowest Tg occurring in pantelleritic suite. For all sample a clear dependence on cooling/heating rate has been recorded. Peak and onset glass transition temperatures show constant viscosity values at differing water contents. Moreover the activation energies yielded by calorimetric and viscosimetry are, within experimental error, identical. This confirm that the calculation of viscosity through the employment of a simple shift factor, as already proposed by previous authors, can be used, for the investigated samples. So far it concern the effect of water on the heat capacities, we show that water has important effect and that complex patterns are observed for different compositional suites.

di Genova, Danilo; Giordano, Daniele; Romano, Claudia; Alletti, Marina; Scaillet, Bruno

2010-05-01

19

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

Microsoft Academic Search

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

Lizbeth O Cisneros; William J Rogers; M. Sam Mannan

2001-01-01

20

Refinement of non-calorimetric determination of the change in heat capacity, ?Cp, of protein unfolding and validation across a wide temperature range  

PubMed Central

The change in heat capacity, ?Cp, upon protein unfolding has been usually determined by calorimetry. A non-calorimetric method which employs the Gibbs-Helmholtz relationship to determine ?Cp has seen some use. Generally, the free energy change upon unfolding of the protein is determined at a variety of temperatures and the temperature at which ?G is zero, Tm, and change in enthalpy at Tm are determined by thermal denaturation and ?Cp is then calculated using the Gibbs-Helmholtz equation. We show here that an abbreviated method with stability determinations at just two temperatures gives values of ?Cp consistent with values from free energy change upon unfolding determination at a much wider range of temperatures. Further, even the free energy change upon unfolding from a single solvent denaturation at the proper temperature, when coupled with the melting temperature, Tm, and the van’t Hoff enthalpy, ?HvH, from a thermal denaturation, gives a reasonable estimate of ?Cp, albeit with greater uncertainty than solvent denaturations at two temperatures. We also find that non-linear regression of the Gibbs-Helmholtz equation as a function of stability and temperature while simultaneously fitting ?Cp, Tm, and ?HvH gives values for the last two parameters that are in excellent agreement with experimental values.

Singh, Deepika Talla; Stites, Wesley E.

2008-01-01

21

Factors determining the formation of complexes between alpha-cyclodextrin and alkylated substances in aqueous solutions: a calorimetric study at 25 degrees C.  

PubMed

The formation of complexes of alpha-cyclodextrin with cycloalkanediols, monoalkylamines and 1-alkanols has been studied calorimetrically at 25 degrees C in water, in phosphoric acid, pH 1.3, and in phosphate buffer, pH 5.5, respectively. When a complex is formed, calorimetry enables the calculation of both the enthalpy and the association constant, from which the free energy and the entropy of the process can be obtained. A model is proposed to explain the unusual trend of the association parameters for substances having alkyl chains longer than six-seven carbon atoms. The main role played by the different functional groups, and the forces involved in the association process, are discussed in the light of the signs and values of the thermodynamic parameters obtained. The effect of the variation of the aqueous medium on the hydration of the interacting substances and the consequent changes in the association parameters have been investigated. To this end, the thermodynamic parameters for the formation of the complexes between the cyclodextrin and 1-pentanol were determined at increasing concentrations of phosphate buffer. There is an increase in the association constant due to a positive entropy contribution originating from the relaxation of water molecules from the hydrophobic hydration cosphere of the alkanol to an increasingly disordered bulk. Deaquation of the interacting substances is the main factor determining the stability of the inclusion complex. PMID:10839121

Castronuovo, G; Elia, V; Iannone, A; Niccoli, M; Velleca, F

2000-05-01

22

Calorimetric electron telescope mission  

Microsoft Academic Search

We are developing the CALorimetric Electron Telescope, CALET, mission for the Japanese Experiment Module—Exposed Facility, JEM-EF, of the International Space Station, ISS. Major scientific objective is a search for nearby cosmic ray sources and dark matter by carrying out a precise measurement of the electrons in 1GeV–20TeV and the gamma-rays in 20MeV-several TeV. CALET has, moreover, a capability to measure

Shoji Torii

2011-01-01

23

Calorimetric investigations of liquid Bi–In–Zn alloys  

Microsoft Academic Search

The integral enthalpies of mixing of liquid Bi–In–Zn alloys were determined at 500°C by a drop calorimetric technique using a Calvet-type microcalorimeter. The ternary liquid miscibility gap in the Bi–In–Zn system at 500°C was confirmed and determined by the calorimetric method for the first time. The three binary interaction parameters and the ternary interaction parameters were optimized based on the

Zuoan Li; Sabine Knott; Adolf Mikula

2007-01-01

24

The calorimetric criterion for a two-state process revisited.  

PubMed Central

The "calorimetric criterion" is one of the important experimental approaches for determining whether protein folding is an "all-or-none" two-state transition (i.e., whether intermediates are present at equilibrium). The calorimetric criterion states that the equivalence of the "measured" calorimetric enthalpy change and the effective two-state van't Hoff enthalpy change demonstrates that there is a two-state transition. This paper addresses the essential question of whether the calorimetric criterion is a necessary and sufficient condition for a two-state process and shows that it is necessary but not sufficient by means of specific examples. Analysis of simple models indicates that the heat capacity curve, regardless of whether it originates from a two-state process or not, can always be decomposed in such a way that the calorimetric criterion is satisfied. Exact results for a three-state model and a homopolymer tetramer demonstrate that the deviation from the calorimetric criterion is not simply related to the population of intermediate states. Analysis of a three-helix bundle protein model, which has a two-state folding from a random coil to ordered (molten) globule, shows that the calorimetric criterion may not be satisfied if the standard linear interpolation of baselines (weighted or unweighted) is employed. A specific example also suggests that the more recently introduced deconvolution method is not necessarily better than the simple calorimetric criterion for distinguishing a two-state transition from a three-state transition. Although the calorimetric criterion is not a sufficient condition for a two-state process, it is likely to continue to be of practical utility, particularly when its results are shown to be consistent with those from other experimental methods.

Zhou, Y.; Hall, C. K.; Karplus, M.

1999-01-01

25

Transient calorimetric diagnostics for plasma processing  

NASA Astrophysics Data System (ADS)

This paper reports on an improvement of the calorimetric method for the determination of energy fluxes from plasma towards substrates by using a transient technique. It provides a short overview of the traditional method used for characterization of plasma-wall-interactions during plasma processing. The mathematical framework of the method and possible implications are discussed. It is shown how the method can be improved to obtain additional and detailed information about the energy influx in a shorter measurement time. For this purpose, the probe bias (if applied), which has commonly been kept constant is varied like in Langmuir probe measurements. The experimental validation of the theoretical considerations emphasizes the potential of the method for control in plasma processing. The possibility how the passive calorimetric probe can be used in continuous measurements for process monitoring without any feedback loops used by other probes, is finally discussed.

Bornholdt, Sven; Kersten, Holger

2013-08-01

26

Pope Benedict XVI Confronts Religious Relativism  

Microsoft Academic Search

Pope Benedict XVI’s inflammatory speech at Regensburg highlights a subtle difference between Benedict and John Paul II. John\\u000a Paul called Muslims and Jews “sons of Abraham,” and he organized high-profile interfaith events. Benedict is more skeptical\\u000a of interreligious dialog and more confrontational toward Islam than was his predecessor. This shift in tone toward Islam stems\\u000a from changed historical circumstances. Islam

Robert Carle

2008-01-01

27

Fe XVI radiative rates (Diaz+, 2013)  

NASA Astrophysics Data System (ADS)

Accurate theoretical energy level, lifetime, and transition probability calculations of core-excited Fe XVI were performed employing the relativistic Multireference Moller-Plesset perturbation theory. In these computations the term energies of the highly excited n<=5 states arising from the configuration 1s22sk2pm3lpnl'q, where k+m+p+q=9, l<=3 and p+q<=2 are considered, including those of the autoionizing levels with a hole-state in the L-shell. All even and odd parity states of sodium-like iron ion were included for a total of 1784 levels. Comparison of the calculated L-shell transition wavelengths with those from laboratory measurements shows excellent agreement. Therefore, our calculation may be used to predict the wavelengths of as of yet unobserved Fe XVI, such as the second strongest 2p-3d Fe XVI line, which has not been directly observed in the laboratory and which blends with one of the prominent Fe XVII lines. (2 data files).

Diaz, F.; Vilkas, M. J.; Ishikawa, Y.; Beiersdorfer, P.

2013-08-01

28

Calorimetric investigations of the enzyme catalyzed sucrose hydrolysis 1 Dedicated to Prof. Günter Marx from the TU-Chemnitz on the occasion of his 60th birthday. 1  

Microsoft Academic Search

The study presents the results of calorimetric investigations of the invertase catalyzed sucrose hydrolysis. The aim of the investigation is the kinetic interpretation of calorimetric curves with respect to the inhibitor effect of selected heavy metal ions and the calorimetric determination of the invertase activity.

Regina Hüttl; Katrin Oehlschläger; Gert Wolf

1999-01-01

29

EDITORIAL: XVI Brazilian Colloquium on Orbital Dynamics  

NASA Astrophysics Data System (ADS)

The XVI Brazilian Colloquium on Orbital Dynamics was held from 26–30 November 2012, at the Biazi Grand Hotel, Serra Negra, São Paulo, Brazil. The Brazilian Colloquia on Orbital Dynamics are scientific events that occur bi-annually and are designed to develop those areas of research in celestial mechanics, orbital dynamics, planetary science, fundamental astronomy, aerospace engineering, and nonlinear systems and chaos. The meeting has been held for 30 years and it brings together researchers, professors and students from South American and also from other continents. Acknowledgements National Council for Scientific and Technological Development – CNPq Coordination for the Improvement of Higher Level – CAPES São Paulo Research Foundation - FAPESP

de Melo, Cristiano F.; Macau, Elbert E. N.; Prado, Antonio B. A.; Hetem Jnr, Annibal

2013-10-01

30

Parallaxes and proper motions. XVI  

NASA Astrophysics Data System (ADS)

Parallaxes and proper motions are presented for 30 stars, most of which are dK-M stars in 20 star fields. Seven of the target stars as well as ten other stars have no previous parallax determinations. Six of the 20 target stars are actually resolved binaries for which both components were measured separately; two of the six are not physical pairs. As in the previous lists in this series, reductions have been made using linear plate constants and results are given to the nearest ten-thousandth of a second of arc and separately in x and y coordinates along with a combined solution. This list is the first in the series which makes full use of the prior selection of parallax stars to achieve the primary goal of the Van Vleck parallax program. This is to determine accurate physical properties and space motions of a large and unbiased sample of unevolved nearby stars of the lower main sequence.

Weis, E. W.; Nations, H. L.; Upgren, A. R.

1983-10-01

31

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

Federal Register 2010, 2011, 2012, 2013

...Notice of Social Security Ruling (SSR...of SSR 13-2p, in which we explain...XVI of the Social Security Act, and to the...determine disability in those claims. 20...policy, as set out in the Commissioner's...regulations, SSRs, Social Security Acquiescence...

2013-02-20

32

Emittance Calorimetric Method.  

National Technical Information Service (NTIS)

A precise measurement of the absorption of weakly absorbing optical material is measured by measuring the temperature rise of the sample when light of the wavelength of interest passes through it. The temperature rise is determined by measuring the emissi...

R. F. Potter D. L. Stierwalt

1977-01-01

33

Calorimetric Ionization Detector  

SciTech Connect

A new mode of operation for ionization detectors is described. The amount of ionization produced in a detector is determined by measuring the amount of heat generated during the carrier collection process. Very high detection sensitivities, including single carrier detection, may be achieved at cryogenic temperatures. Results from an experimental device operated at T = 0.3K is presented.

Luke, P.N.; Beeman, J.; Goulding, F.S.; Labov, S.E.; Silver, E.H.

1989-07-01

34

Radiation beam calorimetric power measurement system  

DOEpatents

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.

Baker, John (Livermore, CA); Collins, Leland F. (Pleasanton, CA); Kuklo, Thomas C. (Ripon, CA); Micali, James V. (Dublin, CA)

1992-01-01

35

A calorimetric unit for measurements of the thermal effects of reactions in solution  

NASA Astrophysics Data System (ADS)

A calorimetric unit for measurements of the thermal effects of reactions in solution was created. The unit was designed following the classic scheme of a hermetic liquid calorimeter working under isoperibolic conditions, it had a thermometric sensitivity of 10-4 K and a calorimetric sensitivity of 10-2 J. The accuracy of calorimeter operation was checked against the heats of solution of potassium chloride. The molar integral enthalpies of solution of glycine in water at 298 K were determined.

Grigorova, E. V.; Bondareva, L. P.; Kadantsev, A. V.; Byval'Tsev, Yu. A.; Khripushin, V. V.; Kornienko, T. S.

2010-09-01

36

Calorimetric system and method  

DOEpatents

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.

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

1998-09-15

37

Calorimetric system and method  

DOEpatents

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).

Gschneidner, Jr., Karl A. (Ames, IA); Pecharsky, Vitalij K. (Ames, IA); Moorman, Jack O. (Boone, IA)

1998-09-15

38

Thermodynamic properties by non-calorimetric methods. Final report  

SciTech Connect

This research program provided 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. The project for the Office of Energy Research focused 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 the following studies: Group-contribution approach for polycyclic aromatic hydrocarbons (naphthalene, phenanthrene, anthracene, pyrene, 3-methylphenanthrene, benzoquinolines, biphenyl/hydrogen system); Group-contribution approach for key monocyclic organic compounds; Molecular spectroscopy and statistical mechanics; and Thermophysical property correlations.

Steele, W.V.; Chirico, R.D.; Collier, W.B.; Strube, M.M.; Klots, T.D. [IIT Research Inst., Chicago, IL (United States)]|[National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States)

1992-12-31

39

Calorimetric determination of the absorbed dose to water for medium-energy x-rays with generating voltages from 70 to 280 kV.  

PubMed

For medium energy x-rays produced with tube voltages from 70 to 280 kV, the absorbed dose to water, D(w), has been determined by means of water calorimetry with relative standard uncertainties ranging from 0.45% to 0.98% at 280 and 70 kV. The results were confirmed by Monte Carlo calculations, in which the ratios of D(w) at 5 cm depth in a reference water phantom to the air kerma free in air, K(a), at the same point in space were compared to the corresponding ratios determined experimentally. The general agreement between measurement and calculation was better than 1%. These results confirm earlier investigations in which the absorbed dose to graphite was determined by means of a graphite extrapolation chamber. For the Monte Carlo calculations, an attempt was made to present a complete uncertainty budget, taking into account type B contributions also. PMID:22975691

Krauss, A; Büermann, L; Kramer, H-M; Selbach, H-J

2012-09-14

40

Calorimetric determination of the absorbed dose to water for medium-energy x-rays with generating voltages from 70 to 280 kV  

NASA Astrophysics Data System (ADS)

For medium energy x-rays produced with tube voltages from 70 to 280 kV, the absorbed dose to water, Dw, has been determined by means of water calorimetry with relative standard uncertainties ranging from 0.45% to 0.98% at 280 and 70 kV. The results were confirmed by Monte Carlo calculations, in which the ratios of Dw at 5 cm depth in a reference water phantom to the air kerma free in air, Ka, at the same point in space were compared to the corresponding ratios determined experimentally. The general agreement between measurement and calculation was better than 1%. These results confirm earlier investigations in which the absorbed dose to graphite was determined by means of a graphite extrapolation chamber. For the Monte Carlo calculations, an attempt was made to present a complete uncertainty budget, taking into account type B contributions also.

Krauss, A.; Büermann, L.; Kramer, H.-M.; Selbach, H.-J.

2012-10-01

41

Pope Benedict XVI: a cautious approach to Middle East peace  

Microsoft Academic Search

Pope Benedict XVI came to the papacy with a very limited track record in terms of Catholic–Jewish relations generally speaking and virtually no public perspective on political issues related to the ongoing Israeli–Palestinian conflict. Since assuming the papacy he has addressed the Middle East political conflict only on a few occasions save for his trip to the region where he

J. T. Pawlikowski

2010-01-01

42

Benedict XVI, the Jewish people and the State of Israel  

Microsoft Academic Search

Benedict XVI has had to contend with invidious comparisons to his predecessor from the outset of his pontificate and this has been reflected in Jewish attitudes towards him as well. At the same time a selective loss of memory has occurred in relation to Pope John Paul II. By examining the documents and initiatives of Cardinal Ratzinger, as well as

David Rosen

2010-01-01

43

POPE BENEDICT XVI'S AFRICA VISIT AND THE CONDOM DEBATE  

Microsoft Academic Search

On Monday, 23 March, Pope Benedict XVI brought his seven-day maiden voyage to Africa to an end. Prior to boarding his plane to Rome at Luanda airport, he reiterated the message he had consistently delivered during his visit, calling on those in public office to fight poverty, corruption and violent conflicts for the sake of the common good, not out

Brian Lewis

44

Pope Benedict XVI's Summorum Pontificum: Reconciling Conflicting Values  

Microsoft Academic Search

This article examines the content of Pope Benedict XVI's Summorum Pontificum and his accompanying Letter to the Bishops and interprets them as a bold attempt to bring liturgical peace to the Catholic Church by freeing the “Tridentine” Latin Mass for general use and promoting internal reconciliation by reconciling theological values which have been at variance since Vatican II. It also

Steven A. Kiczek

2009-01-01

45

Determination of the enthalpy of phase change materials by inverse method from calorimetric experiments. Applications to pure substances or binary solutions  

NASA Astrophysics Data System (ADS)

The aim of this paper is to present an inverse identification method to determine specific enthalpy of PCM from calorimetry experiments. We will focus on the cases of pure substances and ideal binary solutions including the eutectic equilibrium. The corresponding direct model, based on energy balance, is first presented. A classical enthalpy method is then used, which presents the advantage of easily decoupling the thermal transfers from the specific energetic behavior of the material (i.e. thermodynamical phenomenon). In the second part of the paper, we will present the used inverse method (genetic algorithms). The sensibilities of the different parameters for the identification are analyzed. Finally, we will present the identification from DSC experiments (1) at different rates of heating for pure substances and (2) at different concentrations of aqueous solutions of NHACl. In each case, we identify the thermodynamical parameters of the model and compare the corresponding thermograms with the experimental ones. A good agreement is obtained for both cases.

Gibout, Stéphane; Maréchal, William; Franquet, Erwin; Bédécarrats, Jean-Pierre; Haillot, Didier; Dumas, Jean-Pierre

2012-11-01

46

Melting enthalpies of mantle peridotite: calorimetric determinations in the system CaO-MgO-Al 2O 3-SiO 2 and application to magma generation  

NASA Astrophysics Data System (ADS)

High-temperature drop calorimetry in the temperature range of 1398-1785 K was performed for the samples of mixtures of synthetic anorthite (An), diopside (Di), enstatite (En) and forsterite (Fo) with the same compositions as those of primary melts generated at 1.1, 3 and 4 GPa at most 10° above the solidus of anhydrous mantle peridotite in the CaO-MgO-Al 2O 3-SiO 2 system. From the differences between the heat contents ( H T-H 298) of liquid and that of crystal mixture at the liquidus temperature, melting enthalpies of the samples of 1.1, 3 and 4 GPa-primary melt compositions were determined at 1 atm to be 531 ± 39 J · g -1 at 1583 K, 604 ± 21 J · g -1 at 1703 K, 646 ± 21 J · g -1 at 1753 K, respectively. These heat of fusion values suggest that mixing enthalpy of the melt in the An-Di-En-Fo system is approximately zero within the experimental errors when we use the heat of fusion of Fo by Richet et al. (P. Richet, F. Leclerc, L. Benoist, Melting of forsterite and spinel, with implications for the glass transition of Mg 2SiO 4 liquid, Geophys. Res. Lett. 20 (1993) 1675-1678). The measured enthalpies of melting at 1 atm were converted into those for melting reactions which occur under high pressures by correcting enthalpy changes associated with solid-state mineral reactions. Correcting the effects of pressure, temperature and FeO and Na 2O components on the melting enthalpies at 1 atm, heat of fusion values of a representative mantle peridotite just above the solidus under high pressure were estimated to be 590 J at 1.1 GPa and 1523 K, 692 J at 3 GPa and 1773 K, and 807 J at 4 GPa and 1923 K for melting reactions producing liquid of 1 g, with uncertainties of 50 J. By applying these melting enthalpies to a mantle diapir model which generates present MORBs, a potential mantle temperature of 1533 K has been estimated, assuming an eruption temperature of magma of 1473 K.

Kojitani, Hiroshi; Akaogi, Masaki

1997-12-01

47

Calorimetric study of fluorinated methacrylic and vinyl polymer blends: 1. Binary systems: determination of miscibility domains and correlation of glass transition temperatures with blends composition— application to plastic optical fibre cladding  

Microsoft Academic Search

This paper reports a calorimetric study of binary polymer blends prepared by solution mixing of fluoroalkyl methacrylic ester-methyl methacrylate (MMA) copolymers with poly(vinylidene difluoride) (PVDF) or VDF-hexafluoropropene (HFP) (or VDF-trifluoroethylene) copolymers and examines their use as materials in plastic optical fibres (POF) technology. Some interesting blends were also obtained through mechanical mixing in the molten state. As compared to the

Sylvie Pimbert; Guy Levesque

1997-01-01

48

EDITORIAL: Special issue: CAMOP MOLEC XVI  

NASA Astrophysics Data System (ADS)

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 dynamic

Ascenzi, Daniela; Franceschi, Pietro; Tosi, Paolo

2007-09-01

49

A calorimetric probe for plasma diagnostics.  

PubMed

A calorimetric probe for plasma diagnostics is presented, which allows measurements of the power taken by a test substrate. The substrate can be biased and used as an electric probe in order to obtain information about the composition of the total heating power. A new calibration technique for calorimetric probes, which uses monoenergetic electrons at low pressure, has been developed for an improved accuracy. The use of the probe is exemplified with an experiment where both energetic neutral atoms and ions heat the test substrate. PMID:20192493

Stahl, Marc; Trottenberg, Thomas; Kersten, Holger

2010-02-01

50

Calorimetric Analysis of the Plasma Proteome  

PubMed Central

The plasma proteome is a complex mixture of over 3000 proteins that has been routinely exploited by physicians for clinical diagnostic assays. More recently, the low abundance region of the proteome has been examined for potential biomarkers of disease. A novel calorimetric assay has been developed that exploits a new physical basis with which to interrogate the plasma proteome. This section provides a brief overview of the use of the plasma proteome in clinical diagnosis and biomarker discovery and then introduces the new calorimetric assay. Some initial results are reported that indicate the potential clinical utility of the assay.

Garbett, Nichola C.; Miller, James J.; Jenson, A. Bennett; Chaires, Jonathan B.

2009-01-01

51

Calorimetric analysis of the plasma proteome.  

PubMed

The plasma proteome is a complex mixture of more than 3,000 proteins that has routinely been exploited by physicians for clinical diagnostic assays. More recently, the low-abundance region of the proteome has been examined for potential biomarkers of disease. A calorimetric assay has been developed that exploits a new physical basis with which to interrogate the plasma proteome. This article provides a brief overview of the use of the plasma proteome in clinical diagnosis and biomarker discovery and then introduces the new calorimetric assay. Some initial results are reported that indicate the potential clinical utility of the assay. PMID:18061844

Garbett, Nichola C; Miller, James J; Jenson, A Bennett; Chaires, Jonathan B

2007-11-01

52

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

Federal Register 2010, 2011, 2012, 2013

...XVI: Procedures for Handling Requests To File Subsequent Applications for Disability...procedures for handling your request to file a disability claim when you have a pending...XVI: Procedures for Handling Requests To File Subsequent Applications for...

2011-07-28

53

Measurement of the calorimetric energy scale in MINOS  

SciTech Connect

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}).

Hartnell, Jeffrey J.; /Oxford U.

2005-06-01

54

Low temperature sugar-water equilibrium curve by a rapid calorimetric method  

Microsoft Academic Search

A simple rapid enthalpic method based upon a unique calorimetric measurement was developed and applied to sugar solutions at low temperatures to determine the amount of unfreezable water. The experimental results were in good agreement with those obtained by the usual freezing point depression method. The experimental data were also used to test the validity of several literature semi-empirical models

V. Hoff; S CORRERA

1995-01-01

55

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

PubMed

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

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

2001-03-19

56

Calorimetric investigation of the tensile deformation of polyethylene  

Microsoft Academic Search

A calorimetric apparatus for investigating the thermal effects associated with tensile deformation is described. The results of calorimetric measurements made on high- and low-density polyethylene during the deformation process are presented. It is shown that on the interval of strains and loading rates investigated the deformation of polyethylene is energetic in character.

Yu. M. Molchanov; G. A. Molchanova

1970-01-01

57

A calorimetric system based on the LKB 10700-1 flow microcalorimeter  

NASA Astrophysics Data System (ADS)

An electrically calibrated and computer-controlled apparatus based on the LKB 10700-1 flow microcalorimeter was set up and tested by determining the enthalpies of dilution of aqueous solutions of sucrose and HCl at 298.15 K. The obtained results are in good agreement with the corresponding reference values recommended in the literature. The quality of the calorimetric signal in terms of noise, linearity and baseline drift, and the instrument time constant were analyzed. Also investigated were the influences of the flow rate and of the viscosity of the calorimetric liquid on the position of the baseline. The new calibration system enables powers ~25 times smaller than those possible with the original one to be released inside the calorimetric cells. Electrical calibrations carried out with water as the sole calorimetric liquid indicated that the precision of the calibration constant, ?, quickly improved from ~9% to ~0.4% with the increase of the input power, P, from ~2 µW to ~50 µW, and stabilized at ~0.1% for P >= 100 µW. The calibration constant was also found to linearly increase with the flow rate of the calorimetric liquid and to vary by less than 1% over a period of eight months under similar experimental conditions. Finally a new experimental procedure for heat of dilution measurements, which combines calibration and experiment in a single run, was evaluated. This method allows a significant economy in experiment time with apparently no accuracy loss relative to the conventional procedure recommended in the literature.

Leskiv, Miroslav; Bernardes, Carlos E. S.; Minas da Piedade, Manuel E.

2009-07-01

58

Calorimetric Thermometry of Meteoritic Troilite: Early Reconnaissance  

NASA Astrophysics Data System (ADS)

Troilite (FeS) exhibits two solid-state phase transformations, which, according to conventional thermodynamic literature [1,2], occur at 411 +- 3 K (alpha/beta) and 598 +- 3 K (beta/gamma). In principal, the thermal history of a particular troilite sample might be expected to impart structural or strain characteristics that could be measured upon experimental inducement of the phase transformations. To investigate that possibility, we applied differential scanning calorimetry (DSC) to determine the temperatures and enthalpy changes for phase transitions of various troilite samples subjected to controlled heating [3]. Post-heating residues were prepared as polished grain mounts and petrologically characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). Troilite grains separated from the Mundrabilla (octahedrite), PAT91501 (L7 chondrite), and EET83213 (L3 chondrite) meteorites were compared with terrestrial troilite from an ultramafic complex in Del Norte Co., California. Both the alpha/beta and beta/gamma transitions were easily measured by DSC applied to samples on the order of 5 milligrams. Extrapolated-onset temperatures (the DSC approximation of equilibrium transition temperatures) for the alpha/beta transition display a systematic progression as follows: Mundrabilla, PAT91501, EET83213, Del Norte (Fig. 1). At least for Mundrabilla, PAT91501, and Del Norte, there also exists an apparent correlation of transition enthalpy with onset temperature (Fig. 1). (Enthalpy measurements for EET83213 troilite were systematically low, by dilution effects from admixed Ni-Fe metal, and require correction before such comparison.) Although Mundrabilla troilite contains on the order of 1 wt% Cr, and some grains of PAT91501 troilite contain on the order of 1 wt% Ni, it is doubtful that compositional differences can fully account for the measured differences in thermodynamic properties. Instead, it is likely that first-order differences are the consequence of different thermal histories. Multiple samples of Del Norte troilite were used to determine the influence of laboratory-scale thermal histories on DSC signatures by heating and cooling each sample under different programmed conditions. In reconnaissance experiments, maximum temperature achieved during heat treatment appears to be more influential than does either the time maintained at temperature or the heating/cooling rate. The experimentally measured alpha/beta onset temperature shows a systematic decline with maximum temperature achieved during prior heating, suggesting that high onset temperatures are indicative of low maximum temperatures in the natural histories of the troilite samples. That trend is at least qualitatively consistent with the petrologic rankings of the meteorites in which troilite from the relatively unmetamorphosed L3 chondrite shows a higher onset temperature than does troilite from either the highly metamorphosed L7 chondrite or the octahedrite. Additional work should define the limits of a quantitative calibration that might ultimately permit derivation of meteorite thermal histories by calorimetric thermometry of troilite. Samples were kindly provided by E. R. D. Scott (Mundrabilla), C. B. Moore (Del Norte), and the Meteorite Working Group (PAT91501; EET83213 powder from E. Jarosewich). References: [1] Chase M. W. Jr. et al. (1985) JANAF Thermochemical Tables, 3rd ed., 1194. [2] Robie R. A. et al. (1979) Geol. Surv. Bull. 1452, 125. [3] Allton J. H. and Gooding J. L. (1993) LPS XXIV, 21-22. Fig. 1, which appears here in the hard copy, shows the thermodynamics of troilite alpha/beta phase transformations measured by DSC during first-heat cycles.

Allton, J. H.; Wentworth, S. J.; Gooding, J. L.

1993-07-01

59

Pope Benedict XVI to visit Notre Dame on 18th July 2008  

Microsoft Academic Search

The University of Notre Dame Australia is honoured to announce that His Holiness Pope Benedict XVI will visit the University’s Darlinghurst Campus, Sydney on 18 July.\\u000aThe Holy Father has requested to meet young people at risk of alcohol and substance abuse, homelessness and other forms of disadvantage. The University is privileged to host this occasion.\\u000aPope Benedict XVI will

Hayden Ramsay

2008-01-01

60

Comparison of thermodesorption and calorimetric methods of investigation of acidity of zeolites  

SciTech Connect

The thermodesorption of NH/sub 3/ from Na- and H-forms of different types of zeolites (A, Y, mordenite) in the temperature range of 30-440/sup 0/C was studied by the gravimetric method. A correlation was discovered between the temperature-dependent desorption and the calorimetrically measured heat of adsorption. It was shown that thermodesorption data can be used for rapid approximate determination of heats of adsorption of NH/sub 3/ on zeolites.

Kapustin, G.I.; Brueva, T.R.; Kutateladze, G.M.; Klyachko, A.P.

1987-12-01

61

Calorimetric study of melted DNA glass  

NASA Astrophysics Data System (ADS)

In this work we report a detailed calorimetric study using differential scanning calorimetry (DSC) of the glassy behaviour of films made from DNA fibers. We show that after the first irreversible thermal denaturation of the molecules when the sample is reiteratively heated, it reaches a disordered state in which it presents a typical glass behaviour during successive cooling and heating scans. Furthermore, we have investigated the properties of these DNA films in two series of experiments, a slow cooling at different rates followed by a DSC scan upon heating, and ageing at a temperature below the glass transition. Introducing the fictive temperature to characterise the glass allows us to derive quantitative information on the relaxations of the DNA films, in particular to evaluate their enthalpy barrier. A comparison with similar ageing studies on PVAc highlights some specificities of the DNA samples.

Valle-Orero, Jessica; Garden, Jean-Luc; Richard, Jacques; Wildes, Andrew; Peyrard, Michel

2013-02-01

62

Calorimetric investigations of calcium phosphate precipitation  

NASA Astrophysics Data System (ADS)

The kinetics of the early stages of crystallization of calcium phosphate under different initial solution compositions have been studied by calorimetric and light scattering methods. It is found that the total heat of formation of calcium phosphate is negative and depends on the molar ratio Ca/P and the initial pH of the mixture. At initial pH 7.40 and pH 8.62, there are relatively strong repeated endothermic heat effects. The character of this heat conversion is not clear. The light scattering studies do not rule out the possibility of the existence of Ca 4 H(PO 4 ) 3 ·½H 2 O (OCP) crystals in this region at these initial solution pH's rather than Ca 5 (PO 4 ) 3 OH (HAP) and CaHPO 4 ·2H 2 O (DCPD) expected to crystallize at initial higher and lower values of pH, respectively.

Kibalczyc, Wiktor

1987-04-01

63

Calorimetric sensors for energy deposition measurements  

SciTech Connect

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.

Langenbrunner, J.; Cooper, R. [Bechtel Nevada, Los Alamos, NM (United States); Morgan, G. [Los Alamos National Lab., NM (United States)] [and others

1998-12-31

64

40 CFR Appendix Xvi to Part 86 - Pollutant Mass Emissions Calculation Procedure for Gaseous-Fueled Vehicles and for Vehicles...  

Code of Federal Regulations, 2013 CFR

...CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Pt. 86, App. XVI Appendix XVI to Part...44.00995 CH2.658 * 14.6903 * Average ratio of Hydrogen to carbon atoms in HD-5 fuel. (B) C3 H8...

2013-07-01

65

On-device extraction of thermal thin-film properties in calorimetric flow sensors  

NASA Astrophysics Data System (ADS)

In diaphragm-based micromachined calorimetric flow sensors, the convective heat transfer through the test fluid competes with the spurious heat shunt induced by the thin-film diaphragm where the heater and the temperature sensors are embedded. Therefore, accurate knowledge of the thermal transport properties (thermal conductivity and diffusivity) and the emissivity of the diaphragm is mandatory for design, simulation, and optimization of such devices. However, these parameters can differ considerably from those stated for bulk material and they are typically dependent on the production process. Commonly used methods for their determination require the fabrication of custom specimens. In order to overcome this serious drawback, we developed a novel technique to extract the thermal thin-film properties directly from measurements carried out on calorimetric flow sensors. Here, the heat transfer frequency response from the heater to the thermistors is measured and compared to a theoretically obtained relationship arising from an extensive two-dimensional analytical model. This model covers the heat generation by the heater, the heat conduction in the diaphragm, the radiation loss at the diaphragm's surface, and the heat sink caused by the supporting silicon frame. In this contribution, we report in detail on the measurement setup, the theoretical model for the associated parameter extraction, and the results obtained from measurements on calorimetric flow sensors featuring dielectric thin-film diaphragms made of PECVD Si3N4.

Beigelbeck, Roman; Talic, Almir; Cerimovic, Samir; Kohl, Franz; Keplinger, Franz

2011-05-01

66

Adiabatic Heat of Hydration Calorimetric Measurements for Reference Saltstone Waste  

SciTech Connect

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.

Bollinger, James

2006-01-12

67

Calorimetric study of peroxycarboxylic ester synthesis.  

PubMed

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

Fritzsche, L; Knorr, A

2008-07-15

68

Adaptive measurement control for calorimetric assay  

SciTech Connect

The performance of a calorimeter is usually evaluated by constructing a Shewhart control chart of its measurement errors for a collection of reference standards. However, Shewhart control charts were developed in a manufacturing setting where observations occur in batches. Additionally, the Shewhart control chart expects the variance of the charted variable to be known or at least well estimated from previous experimentation. For calorimetric assay, observations are collected singly in a time sequence with a (possibly) changing mean, and extensive experimentation to calculate the variance of the measurement errors is seldom feasible. These facts pose problems in constructing a control chart. In this paper, the authors propose using the mean squared successive difference to estimate the variance of measurement errors based solely on prior observations. This procedure reduces or eliminates estimation bias due to a changing mean. However, the use of this estimator requires an adjustment to the definition of the alarm and warning limits for the Shewhart control chart. The authors propose adjusted limits based on an approximate Student`s t-distribution for the measurement errors and discuss the limitations of this approximation. Suggestions for the practical implementation of this method are provided also.

Glosup, J.G.; Axelrod, M.C.

1994-10-01

69

Calorimetric studies on the phenolic glycoside D(-)-salicin.  

PubMed

A pure orthorhombic phase sample of D(-)-salicin was purified and characterized for calorimetric measurements. From differential scanning calorimetry (DSC) measurements it was found that the onset and maximum temperatures of the fusion peak were T(on) = (473.30 +/- 0.05) K and T(max) = (474.74 +/- 0.05) K, respectively, and that the corresponding standard enthalpy of fusion was Delta(cr)(l) H(m)(o) = (55.5 +/- 0.4) kJ mol(-1). From the last two values the standard entropy of fusion is calculated as Delta(cr)(l) S(m)(o) = (116.9 +/- 0.4) J mol(-1) K(-1). The standard molar enthalpy of formation of orthorhombic D(-)-salicin at T = 298.15 K, was determined as Delta(f) H(m)(o) (C(13)H(18)O(7), cr, orthorhombic) = -(1366.9 +/- 3.2) kJ mol(-1), by combustion calorimetry. From the results of solution calorimetry obtained in this work and some auxiliary values taken from the literature the enthalpy of reaction of hydrolysis of D(-)-salicin to produce beta-glucose and o-hydroxybenzyl alcohol was found marginally thermoneutral, if the uncertainty interval was considered. Additionally, specific heat capacity measurements on the orthorhombic phase, glass and liquid-quenched glass obtained by DSC was reported. PMID:18484613

Pinto, Susana S; Diogo, Hermínio P

2008-12-01

70

Ungulates and the Middle-to-Upper Paleolithic transition at Grotte XVI (Dordogne, France)  

Microsoft Academic Search

Grotte XVI (Dordogne, France) contains a rich archaeological sequence that begins during the Mousterian and continues through the Magdalenian and includes Châtelperronian and early Aurignacian assemblages. Analyses of the ungulates from this site show no significant change in skeletal part representation, butchering intensity (as measured by cut mark numbers and placement), degree of bone fragmentation, and intensity of carnivore damage

Donald K. Grayson; Françoise Delpech

2003-01-01

71

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

SciTech Connect

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.

Weisberg, Joel M., E-mail: jweisber@carleton.edu [Department of Physics and Astronomy, Carleton College, Northfield, MN 55057 (United States); Paglen, Trevor, E-mail: trevor@paglen.com

2012-10-01

72

Benedict XVI and Islam: Indonesian Public Reactions to the Regensburg Address  

Microsoft Academic Search

This paper examines the responses of the Indonesian public sphere in the reform era to Pope Benedict XVI's call for interfaith dialogue in his speech made in Regensburg on 12 September 2006. It explores five op-ed (opinion and editorial) columns published by Indonesian newspapers (Republika, Harian Pikiran Rakyat, The Jakarta Post and Gatra), a piece posted by the online Wahid

Al Makin

2009-01-01

73

A DIPLOMACY OF CANDOR: POPE BENEDICT XVI ON THE GLOBAL STAGE  

Microsoft Academic Search

In his time in the papacy, Pope Benedict XVI has displayed a straightforward style of diplomacy, viewing it as a safeguard to the common interests of humankind. His initiatives to date demonstrate five key elements of this diplomacy: respecting objective moral truth, facilitating practical inter-faith dialogue, building realistic bridges, intervening for peace, and prioritizing peace over markets. Each of these

Bernard J. OConnor

2006-01-01

74

Technology and Freedom: Pope Benedict XVI on Faith, Reason, and Politics  

Microsoft Academic Search

Pope Benedict XVI connects the problem of technology to the question of how human beings have chosen to employ their reason, both in their encounter with faith and in their pursuit of human freedom. His analysis involves a penetrating study of the history of modern thought, a history he distinguishes from the practice of classical political philosophy. Benedict's willingness to

Patrick N. Cain

2012-01-01

75

Pope Benedict XVI within the context of Israel and Holy See relations  

Microsoft Academic Search

The pontificate of Benedict XVI is undoubtedly shaped by his personality as a profound thinker and one who is much more a philosopher than a politician. Management seems not to be his trade. With his intellectual mind he shuns anything that smells of populism. The mass media has an inherent difficulty in placing him within their traditional parameters. The paradigm

Mordechay Lewy

2010-01-01

76

Education as a path to love: A leadership perception of Benedict XVI's challenge to Catholic education  

Microsoft Academic Search

This qualitative study presents a renewed definition of Catholic education based on the theological notion of love-caritas-agape which Benedict XVI describes in the encyclical Deus Caritas Est (2005). The traits of love illustrated in the first part of the encyclical have been developed within a model of education enriched by the contributions of contemporary scholars as Bernard Lonergan (philosophy of

Stefano Del Bove

2008-01-01

77

Sensitivity and systematics of calorimetric neutrino mass experiments  

SciTech Connect

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.

Nucciotti, A.; Cremonesi, O.; Ferri, E. [Dipartimento di Fisica, Universita di Milano Bicocca and INFN Sezione di Milano-Bicocca Piazza della Scienza, 3, 20126 Milano (Italy)

2009-12-16

78

Application of a downstream calorimetric probe to reactive plasma  

SciTech Connect

We explore the application of calorimetric probe located downstream from the plasma zone. By positioning the probe in a downstream location, the probe signal can be correlated with the integral energy flux carried by the effluent species as they propagate downstream from the plasma zone. Because the integral energy flux channeled downstream depends on the plasma conditions, it is possible to infer the plasma conditions from the probe response even though the probe is located away from the plasma zone. A calorimetric probe, based on resistance-temperature detector principle, adequate for fluorine plasma exposure is constructed. Probe operation is demonstrated for NF{sub 3}-Ar plasmas.

Chen, I.-S.; Neuner, Jeffery W.; Chen, Philip S.H.; Welch, James J.; DiMeo, Frank Jr. [ATMI, 7 Commerce Drive, Danbury, Connecticut 06810 (United States)

2005-12-05

79

20 CFR 416.903 - Who makes disability and blindness determinations.  

Code of Federal Regulations, 2013 CFR

...will evaluate only the mental impairment, and a physician will evaluate the nonmental impairment. (f) Determinations for childhood impairments. In making a determination under title XVI with respect to the disability of a child to whom...

2013-04-01

80

Absolute calorimetric calibration of low energy brachytherapy sources  

NASA Astrophysics Data System (ADS)

In the past decade there has been a dramatic increase in the use of permanent radioactive source implants in the treatment of prostate cancer. A small radioactive source encapsulated in a titanium shell is used in this type of treatment. The radioisotopes used are generally 125I or 103Pd. Both of these isotopes have relatively short half-lives, 59.4 days and 16.99 days, respectively, and have low-energy emissions and a low dose rate. These factors make these sources well suited for this application, but the calibration of these sources poses significant metrological challenges. The current standard calibration technique involves the measurement of ionization in air to determine the source air-kerma strength. While this has proved to be an improvement over previous techniques, the method has been shown to be metrologically impure and may not be the ideal means of calbrating these sources. Calorimetric methods have long been viewed to be the most fundamental means of determining source strength for a radiation source. This is because calorimetry provides a direct measurement of source energy. However, due to the low energy and low power of the sources described above, current calorimetric methods are inadequate. This thesis presents work oriented toward developing novel methods to provide direct and absolute measurements of source power for low-energy low dose rate brachytherapy sources. The method is the first use of an actively temperature-controlled radiation absorber using the electrical substitution method to determine total contained source power of these sources. The instrument described operates at cryogenic temperatures. The method employed provides a direct measurement of source power. The work presented here is focused upon building a metrological foundation upon which to establish power-based calibrations of clinical-strength sources. To that end instrument performance has been assessed for these source strengths. The intent is to establish the limits of the current instrument to direct further work in this field. It has been found that for sources with powers above approximately 2 muW the instrument is able to determine the source power in agreement to within less than 7% of what is expected based upon the current source strength standard. For lower power sources, the agreement is still within the uncertainty of the power measurement, but the calorimeter noise dominates. Thus, to provide absolute calibration of lower power sources additional measures must be taken. The conclusion of this thesis describes these measures and how they will improve the factors that limit the current instrument. The results of the work presented in this thesis establish the methodology of active radiometric calorimetey for the absolute calibration of radioactive sources. The method is an improvement over previous techniques in that there is no reliance upon the thermal properties of the materials used or the heat flow pathways on the source measurements. The initial work presented here will help to shape future refinements of this technique to allow lower power sources to be calibrated with high precision and high accuracy.

Stump, Kurt E.

81

Calorimetric measurements of energy transfer efficiency and melting efficiency in CO2 laser beam welding  

NASA Astrophysics Data System (ADS)

The previous calorimetric studies of weld melting efficiency and arc efficiency in the GTAW and PAW processes have naturally led us to speculate as to the magnitude of the efficiencies in the LBW process which to data have also not been adequately investigated. Most welding engineers that have had experience with the LBW process are acutely aware that the metals' absorptivity, the surface finish, and the laser wavelength, all play an important role in affecting the energy transfer efficiency, but the extent of their influence and our understanding of the influence of other process variables is not well understood. In addition, it is widely thought that only the LBW or EBW processes can be selected for applications where thermal damage and distortion from the welding process must be kept to a minimum. For these reasons, we have looked forward to performing these calorimetric experiments since they potentially can answer such important questions as: whether or not the melting efficiency of the LBW process is superior to that obtainable with conventional GTAW and PAW welding processes. This study was prompted by poor production yields on switching device due to cracking of the ceramic header after final closure welding with the CO2 LBW process. This calorimetric study was begun in hopes of determining if allowed variations in production process control variables were responsible for increases in heat input and the resulting thermal stresses. By measuring the net heat input to the workpiece with the calorimeter and by measuring the laser output energy and the weld fusion zone size it was possible to determine the magnitudes of both the energy transfer efficiency and the melting efficiency as well as observe their dependence on the process variables.

Fuerschbach, P. W.

82

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

Federal Register 2010, 2011, 2012, 2013

...Security Ruling, SSR 13-2p; Titles II and XVI: Evaluating Cases Involving Drug Addiction and Alcoholism (DAA); Correction...first column, question 8. ``What evidence do we need in cases involving DAA?'', a., italicize the subheading...

2013-03-22

83

20 CFR 416.572 - Are title II and title VIII benefits subject to adjustment to recover title XVI overpayments?  

Code of Federal Regulations, 2013 CFR

...416.572 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL...title XVI overpayments from benefits payable to you under title II or title VIII of the Social Security Act. (2) Benefits payable. For...

2013-04-01

84

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

... Section 408.930 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS...under title II or title XVI of the Social Security Act. (2) Benefits payable. For purposes of...

2013-04-01

85

78 FR 22361 - Social Security Ruling, SSR 13-1p; Titles II and XVI: Agency Processes for Addressing Allegations...  

Federal Register 2010, 2011, 2012, 2013

...II and XVI: Agency Processes for Addressing Allegations of Unfairness, Prejudice, Partiality, Bias, Misconduct, or Discrimination by Administrative Law Judges (ALJs); Correction AGENCY: Social Security Administration. ACTION: Notice of Social...

2013-04-15

86

78 FR 8217 - Social Security Ruling, SSR 13-1p; Titles II and XVI: Agency Processes for Addressing Allegations...  

Federal Register 2010, 2011, 2012, 2013

...II and XVI: Agency Processes for Addressing Allegations of Unfairness, Prejudice, Partiality, Bias, Misconduct, or Discrimination by Administrative Law Judges (ALJs); Correction AGENCY: Social Security Administration. ACTION: Notice of Social...

2013-02-05

87

78 FR 9987 - Social Security Ruling, SSR 13-1p; Titles II and XVI: Agency Processes for Addressing Allegations...  

Federal Register 2010, 2011, 2012, 2013

...II and XVI: Agency Processes for Addressing Allegations of Unfairness, Prejudice, Partiality, Bias, Misconduct, or Discrimination by Administrative Law Judges (ALJs); Correction AGENCY: Social Security Administration. ACTION: Notice of Social...

2013-02-12

88

Calorimetric Low Temperature Detectors for Heavy Ion Physics  

Microsoft Academic Search

Calorimetric low temperature detectors have the potential to become powerful tools for applications in many fields of heavy ion physics. A brief overview of heavy ion physics at present and at the next generation heavy ion facilities is given with a special emphasis on the conditions for heavy ion detection and the potential advantage of cryogenic detectors for applications in

P. Egelhof; S. Kraft-Bermuth

89

Isoperibolic Calorimetric Cell with Electronic Integrator Circuit for Temperature Measurement  

Microsoft Academic Search

An isoperibolic calorimetric cell, formed with double plastic insulation, is connected to a conventional Dewar glass. The cell has a lid on which are placed an electronic thermometer and an electric resistor to provide the cell with specific quantities of electrical work.The thermometer, built with an LM35 integrator circuit, presents an output potential signal which is proportional to the temperature

Paola Martínez; Liliana Giraldo; Edgar Vargas; Juan Carlos Moreno

2005-01-01

90

Calorimetric insights into the synthesis of templated materials  

Microsoft Academic Search

Major recent advancesIn situ calorimetric studies of zeolite synthesis have been performed under conditions where the growing templated zeolite remains in contact with its aqueous solution. Nanoparticles form first, then aggregate to form the zeolite. As surface area decreases, hydroxyl ions begin to desorb from the shrinking surface of the growing crystals, raising the pH, causing a shift from exothermic

Alexandra Navrotsky

2005-01-01

91

Energy associated with dislocations: A calorimetric study using synthetic quartz  

NASA Astrophysics Data System (ADS)

High temperature oxide melt solution calorimetry was used to study the energy associated with dislocations in quartz by comparing undeformed and deformed single crystals of synthetic quartz. Samples were deformed at 698 K, 1000 1500 MPa at a strain rate of 10-5 sec-1. Two sets of calorimetric measurements were made: (i) using a Pt capsule as a container for powdered sample, and (ii) using pellets made from sample powder without any container. For the first set of measurements, the undeformed sample with a dislocation density of enthalpy is sum of heat content H 973- H 295 and enthalpy of solution in molten lead borate at 973 K of 39.22 ± 1.00 kJ mol-1, while the sample deformed in the dislocation creep regime with a dislocation density of 6 × 1010 to 1 × 1011 cm-2 gave an enthalpy of 38.59 ± 0.78 kJ mol-1. For the second set of measurements the measured enthalpy of the undeformed sample was 38.87 ± 0.31 kJ mol-1, and that of a deformed sample with a dislocation density of 3 × 1010 to 1 × 1011 cm-2 was 38.24 ± 0.58 kJ mol-1. The present study and previous theoretical calculations and estimates are consistent and suggest that the energy associated with dislocations in quartz is ˜ 0.6 ± 0.6 kJ mol-1 for a dislocation density of ˜ 1011 cm-2; a precise value is difficult to determine because of the overlapping errors. These results indicate that for geologically realistic dislocation densities, the maximum excess energy due to dislocations would be ˜ 0.5 kJ mol-1 for most minerals; the exact value would depend on the Burgers vector as well as the shear modulus.

Liu, M.; Yund, R. A.; Tullis, J.; Topor, L.; Navrotsky, A.

1995-03-01

92

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

SciTech Connect

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.

Steele, W.V.; Chirico, R.D.; Collier, W.B.; Strube, M.M. [IIT Research Inst., Chicago, IL (United States)]|[National Inst. for Petroleum and Energy Bartlesville, OK (United States)

1989-12-31

93

Calorimetric studies of curium complexation. 2. Amino carboxylates  

Microsoft Academic Search

Calorimetric titrations using the long-lived isotope of curium (curium-248) have been conducted with nitrilotriacetate, trans-1,2-cyclohexanedinitrilotetraacetate, and trimethylenedinitrilotetraacetate. The data plus the stability constants measured previously allowed calculations of the thermodynamic parameters of the 1:1 complexation. Similar titrations were conducted with europium to provide comparison of the lanthanide and actinide trivalent ion behaviors. The enthalpy values for the amino polycarboxylate complexing

G. R. Choppin; E. N. Rizkalla; J. C. Sullivan

1987-01-01

94

Calorimetric low temperature detectors for mass identification of heavy ions  

Microsoft Academic Search

The energy sensitive detection of heavy ions with calorimetric low temperature detectors (CLTDs) is investigated for the energy range E=0.1-1 MeV\\/u, commonly used for accelerator mass spectrometry (AMS). Such measurements complement earlier investigations [1, 2] at higher energies (E=5-300 MeV\\/u) where an energy resolution of DeltaE\\/E=1-2×10-3 was obtained for various ion species. The detectors used consist of sapphire absorbers and

S. Kraft; A. Bleile; P. Egelhof; R. Golser; O. Kisselev; W. Kutschera; H. J. Meier; A. Priller; A. Shrivastava; P. Steier; C. Vockenhuber; M. Weber

2002-01-01

95

Calorimetric studies of isothermal curing of phase separating epoxy networks  

Microsoft Academic Search

To get a better understanding of the curing process of multi-component thermosets differential scanning calorimetric (DSC) and temperature modulated DSC (TMDSC) measurements were performed during isothermal curing of semi-interpenetrating polymer networks (semi-IPNs) with amounts of 10 or 20wt.% of linear polymer and of the corresponding pure networks at temperatures between 333 and 393K. The network component consists of diglycidylether of

W. Jenninger; J. E. K. Schawe; I. Alig

2000-01-01

96

THEORETICAL WAVELENGTHS OF Fe XVI L-SHELL TRANSITIONS AND COMPARISON WITH LABORATORY MEASUREMENTS AND CHANDRA OBSERVATIONS OF CAPELLA  

SciTech Connect

We have used the relativistic multi-reference Moller-Plesset perturbation theory to calculate the energy levels of Fe XVI, including those of the autoionizing levels with a hole state in the L shell. Comparison of the resulting L-shell transition wavelengths with those from recent laboratory measurements shows remarkable agreement, i.e., agreement within the experimental uncertainties. Our calculation allows us to predict the wavelength of the second strongest 2p-3d Fe XVI line, which has not yet been directly observed in the laboratory, to be 15.266 A. This wavelength is within 0.0042 A of the strong Fe XVII line commonly labeled 3D. Relying on the high accuracy of our calculations, we have reassigned two previously identified lines and predict a different location than previously thought for the strongest Fe XVI magnetic quadrupole transition. Inspection of the spectra of Capella recorded with the transmission grating spectrometers on the Chandra X-ray Observatory yields features corresponding to the predicted location of the innershell excited Fe XVI lines. These features have not been identified before. Our analysis shows that these features are most likely from Fe XVI.

Beiersdorfer, P. [Physics Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Diaz, F.; Ishikawa, Y. [Department of Chemistry and the Chemical Physics Program, University of Puerto Rico, San Juan, PR 00931 (United States)

2012-02-01

97

Radioactivity measurements of metallic [sup 192]Ir sources by calorimetric methods  

SciTech Connect

The necessity of establishing the traceability of dose measurement in brachytherapy [sup 192]Ir sources is realized by physicians and researchers in the medical field. Standard sources of various shapes such as [open quotes]hairpin,[close quotes] [open quotes]single pin,[close quotes] [open quotes]thin wire,[close quotes] and [open quotes]seed[close quotes] for calibrating ionization chambers in hospitals are being demanded. Nominal activities of not only these source products but also the standard sources have been so far specified by [open quotes]apparent[close quotes] values. Determination of [open quotes]absolute[close quotes] activity by an established means such as 4pi-beta-gamma coincidence counting is not practical because quantitative dissolution of metallic iridium is very difficult. We tried to determine the [open quotes]absolute[close quotes] activity by a calorimetric method in a fully nondestructive way.

Genka, Tsuguo; Iwamoto, Seikichi; Takeuchi, Norio (Japan Atomic Energy Research Institute, Ibaraki-ken (Japan))

1992-01-01

98

Collagen XVI induces formation of focal contacts on intestinal myofibroblasts isolated from the normal and inflamed intestinal tract.  

PubMed

In Crohn's disease (CD) the stress-shield of intestinal subepithelial myofibroblasts (ISEMF) provided by intact tissue is disturbed due to inflammation and thus, cells start with remodelling activities. This is characterized by increased numbers of collagen-producing ISEMF causing an uncontrolled, irreversible wound-healing response to the chronic inflammation of the gastrointestinal tract. Reconstitution of the original ECM leads ISEMF to exit this cycle. In contrast, during fibrosis, ISEMF persist. It is known that ISEMF produce and deposit collagen types I, III, IV and V; however synthesis and the role of fibrillar peripheral molecules like collagen type XVI have not been addressed yet. Here, we have analyzed the distribution of collagen XVI in the normal and inflamed bowel wall, its gene and protein expression by ISEMF of different inflammation stages, the cell-matrix interactions in different phases of the inflammatory process and their effect on cell spreading, proliferation and migration. Collagen XVI is deposited in the submucosa of the intestinal wall where it co-localizes with fibrillin-1 and integrin alpha1. ISEMF reveal increasing gene and protein expression of collagen XVI concurrent to increasing inflammation. ISEMF reveal more mature focal adhesion contacts when seeded on collagen XVI resulting in an extensive cell spreading. This involves recruitment of alpha1beta1 integrin, which shows increased cell surface expression on ISEMF in late stages of inflammation. We assume that collagen XVI promotes persistence of ISEMF in the normal and, even stronger in the inflamed bowel wall by stabilizing focal adhesion contacts via cell-matrix interaction preferentially through recruitment of alpha1ss1 integrin into the tips of the focal adhesion contacts. PMID:19931388

Ratzinger, Sabine; Eble, Johannes A; Pasoldt, Anja; Opolka, Alfred; Rogler, Gerhard; Grifka, Joachim; Grässel, Susanne

2009-11-18

99

A comprehensive set of UV and x-ray radiative transition rates for Fe XVI  

NASA Astrophysics Data System (ADS)

Sodium-like Fe XVI is observed in collisionally ionized plasmas such as stellar coronae and coronal line regions of active galactic nuclei including black hole-accretion disc environments. Given its recombination edge from neon-like Fe XVII at ~\\!25 Å, the Fe XVI bound-bound transitions lie in the soft x-ray and EUV (extreme ultraviolet) range. We present a comprehensive set of theoretical transition rates for radiative dipole allowed E1 transitions including fine structure for levels with nell(SLJ)<=10, ell<=9 using the relativistic Breit-Pauli R-matrix (BPRM) method. In addition, forbidden transitions of electric quadrupole (E2), electric octupole (E3), magnetic dipole (M1) and magnetic quadrupole (M2) type are presented for levels up to 5g(SLJ) from relativistic atomic structure calculations in the Breit-Pauli approximation using code SUPERSTRUCTURE. Some of the computed levels are autoionizing, and oscillator strengths among those are also provided. BPRM results have been benchmarked with the relativistic coupled cluster method and the atomic structure Dirac-Fock code GRASP. Levels computed with the electron collision BPRM codes in bound state mode were identified with a procedure based on the analysis of quantum defects and asymptotic wavefunctions. The total number of Fe XVI levels considered is 96, with 822 E1 transitions. Tabulated values are presented for the oscillator strengths f, line strengths S and Einstein radiative decay rates A. This extensive dataset should enable spectral modelings up to highly excited levels, including recombination-cascade matrices.

Nahar, S. N.; Eissner, W.; Sur, C.; Pradhan, A. K.

2009-03-01

100

Thermodynamic model for calorimetric and phase coexistence properties of coal derived fluids  

Microsoft Academic Search

The objective of this project is to develop a thermodynamic model for phase equilibria and calorimetric properties of coal derived fluids. A model for phase equilibria of coal derived liquids is already available. This model is to be extended to include calorimetric properties. The modification involves the use of the modified UNIFAC correlation with suitably regressed parameters, combined with an

Kabadi

1989-01-01

101

A no-calorimetric method for measuring SAR in MRI  

NASA Astrophysics Data System (ADS)

During an MR procedure, the patient absorbs a portion of the transmitted RF energy, which may result in tissue heating and other adverse effects, such as alterations in visual, auditory and neural functions. The Specific Absorption Rate (SAR), in W/kg, is the RF power absorbed per unit mass of tissue and is one of the most important parameters related with thermal effects and acts as a guideline for MRI safety. Strict limits to the SAR levels are imposed by patient safety international regulations (CEI - EN 60601 - 2 - 33) and SAR measurements are required in order to verify its respect. The recommended methods for mean SAR measurement are quite problematic and often require a maintenance man intervention and long stop machine. For example, in the CEI recommended pulse energy method, the presence of a maintenance man is required in order to correctly connect the required instrumentation; furthermore, the procedure is complex and requires remarkable processing and calculus. Simpler are the calorimetric methods, also if in this case long acquisition times are required in order to have significant temperature variations and accurate heat capacity knowledge (CEI - EN 60601 - 2 - 33). The phase transition method is a new no-calorimetric method to measure SAR in MRI which has the advantages to be very simple and to overcome all the typical calorimetric method problems. It does not require in gantry temperature measurements, any specific heat or heat capacity knowledge, but only mass and time measurement. On the other hand, it is necessary to establish if all deposited power SAR can be considered acquired and measured. In this paper, that will be shown.

Romano, Rocco; Acernese, Fausto; Barone, Fabrizio

2011-03-01

102

Calorimetric measurements of inward-flowing fraction for complex glazing and shading systems  

SciTech Connect

This paper presents a calorimetric measurement of layer-specific inward-flowing fractions of absorbed solar energy for a number of geometric configurations common in fenestrations with shading. The inward-flowing fractions are found to be relatively insensitive to exterior conditions. Results for an interior venetian blind over double glazing agree with thermal model calculations in literature, and are the first layer-specific verification of these calculations. It is argued that a data base of these inward-flowing fractions for a suitably broad class of geometries will make possible the determination of solar heat gain coefficient from noncalorimetric measurements of solar-optical properties of complex fenestration components, a procedure termed solar-thermal separation.

Klems, J.H.; Kelley, G.O.

1995-05-01

103

Calorimetric study on the effect of 60Co ?-rays on the growth of microorganisms  

NASA Astrophysics Data System (ADS)

Using a calorimeter equipped with 24 sample units, the heat evolution from growing Saccharomyces cerevisiae, Escherichia coli and spores of Bacillus pumilus and Bacillus stearothermophilus was detected in the form of growth thermograms. Irradiation with 60Co ?-rays affected the growth pattern, which was used for a quantitative analysis of the effect on microorganisms. Irradiation of B. pumilus and B. stearothermophilus spores led to dose-dependent delays in growth, indicating a bactericidal effect. In case of 60Co ?-irradiated S. cerevisiae, a dose-dependent reduction of the growth rate constant was observed together with the retardation in growth, indicating a combination of bactericidal and bacteriostatic effects. An equation to determine the number of survivors on the basis of the retardation in growth t? and the growth rate constant /? was developed, which proved the opportunity to use the calorimetric technique in predictive microbiology.

Wirkner, Sandra; Takahashi, Katsutada; Furuta, Masakazu; Hayashi, Toshio

2002-03-01

104

Interaction of methotrexate, folates, and pyridine nucleotides with dihydrofolate reductase: calorimetric and spectroscopic binding studies.  

PubMed Central

The thermodynamic parameters, deltaG, deltaH, and deltaS characterizing the tight binding of methotrexate, folates, and pyridine nucleotides to chicken liver dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) have been determined from calorimetric and fluorescence measurements. At 25 degrees the binding of NADPH and NADP+ is characterized by small negative enthalpies and large positive entropies whereas the binding of the folates and methotrexate is accompanied by large negative enthalpies and small negative entropies. In addition, the enthalpy of methotrexate-enzyme interaction demonstrates a proton transfer associated with binding; this is not the case with folate and dihydrofolate, thus confirming the conclusions drawn from the observed difference spectra characteristic of the interaction of methotrexate and substrates with the enzyme. The implications of these results are discussed in terms of the nature of the binding process, conformational changes in the enzyme, and the nature of the active site region.

Subramanian, S; Kaufman, B T

1978-01-01

105

Low-temperature calorimetric evaluation of aluminum-lithium alloys  

NASA Astrophysics Data System (ADS)

Low temperature calorimetric measurements have been made on a series of binary aluminum alloys containing 1-10 at. % lithium. The heat capacity data are analyzed in terms of an electronic and a lattice contribution. Accordingly, the low level of lithium addition yields appreciable changes in the electronic density-of-states at Fermi level and the characteristic Debye temperature of lattice. These results reflect certain degrees of electron localization between aluminum and lithium atoms, providing a fundamental basis for solid solution strengthening in the lightweight materials with great potential in aerospace applications.

Wang, C. R.; Neeleshwar, S.; Chen, Y. Y.; Ho, J. C.

2003-12-01

106

Calorimetric analysis of fungal degraded wood  

SciTech Connect

Endothermic transition and gross heat of combustion of aspenwood subjected to degradation by Lenzites trabea and Polyporus versicolor were determined by using differential scanning calorimetry (DSC) and an adiabatic O bomb. Endothermic peak areas of undegraded and fungi-degraded wood differed from each other at all levels of weight loss. The regression analysis of the DSC data vs. weight loss revealed a significant relations, although not highly correlated, for P. versicolor-degraded specimens and a nonsignificant relation for L. trabea-degraded specimens; weight loss and gross heat of combustion values of degraded specimens were significantly correlated.

Blankenhorn, P.R.; Baldwin, R.C.; Merrill, W. Jr.; Ottone, S.P.

1980-01-01

107

Novel micro-calorimetric spectroscopy for mine detection  

SciTech Connect

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.

Datskos, P.G. [Oak Ridge National Lab., TN (United States)]|[Univ. of Tennessee, Knoxville, TN (United States); Rajic, S.; Egert, C.M.; Datskou, I. [Oak Ridge National Lab., TN (United States)

1998-03-01

108

Low-temperature calorimetric properties of zinc ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Calorimetric measurements between 1 and 40 K by a thermal relaxation technique have been made on zinc ferrite nanoparticles prepared from an aerogel process. The expected ?-type heat-capacity peak near 10 K, which corresponds to a long-range antiferromagnetic transition in the bulk form of this material, is greatly suppressed. Broad peaks begin to prevail after the sample is annealed at 500 or 800 °C, but ball milling of the nanoparticles leads to almost complete disappearance of the low-temperature ordering. In all cases, calorimetrically based magnetic entropy at 40 K accounts for only a fraction of 2R ln(2S+1) with S=5/2 for Fe3+. These results are corroborated by magnetic data, which also indicate magnetic ordering at high temperatures. Such observations can be understood by considering the relative distribution of Fe3+ between two nonequivalent (A and B) sites in the spinel-type lattice. In particular, the as-prepared fine particles show large Fe3+ occupancy of the A sites, whereas these ions prefer the B sites in bulk zinc ferrite. Meanwhile, the lattice heat capacity is enhanced, yielding effective Debye temperatures of 225, 285, 345, and 360 K for the as-prepared, 500 °C-annealed, 800 °C-annealed, and ball milled sample, respectively, in contrast to 425 K for the bulk material.

Ho, J. C.; Hamdeh, H. H.; Chen, Y. Y.; Lin, S. H.; Yao, Y. D.; Willey, R. J.; Oliver, S. A.

1995-10-01

109

REVOLUCIÓN CIENTÍFICA, TECNOLÓGICA Y ENERGÉTICA: LA INFLUENCIA SOBRE EL PENSAMIENTO ECONÓMICO DE LOS SIGLOS XVI Y XVII 1  

Microsoft Academic Search

This work places some of the economic writings of the XVI and XVII centuries in the context of the technological and scientific revolutions of the period and those preceding it, the transition phase from feudalism into capitalism. It also discusses the change in focus by the aut- hors, from theological, logical and ethic subjects to the \\

SINCLAIR MALLET; GUY GUERRA; CONTI MACEDO; TANIA MARÍA DE CASTRO; CARVALHO NETO

2006-01-01

110

Calorimetric approach for 3D dosimetry of high intensity therapeutic electron beams  

NASA Astrophysics Data System (ADS)

The technique of High Dose Rate Intra-Operative Radiation Therapy (HDR-IORT) consists in the delivery of irradiation immediately after the removal of a cancerous mass, where the same incision is used to focalize the radiation to the tumour bed. Given its particular characteristics, IORT requires dose measurements that are different from those requested in external radiotherapy treatments. The main reason lies in the fact that in this case a single high dose must be delivered to a target volume whose extension and depth will be determined directly during the operation. Because of this peculiar characteristics, until now there is not a dosimetric system able to detect the electron beam giving at once a realtime response and an extensive spatial measure of the absorbed dose. Within the framework of a research project of the INFN (Italian National Institute of Nuclear Physics), we proposed a new system to overcome the problems, Dosiort. The final set-up is a solid phantom having a density approximately 1 g/cm3 with sensitive layers of scintillating fibres at fixed positions in a calorimetric configuration for the containment of electrons of energy 4-12 MeV. The prototype will be able to define the physical and geometrical characteristics of the electron beam (energy, isotropy, homogeneity, etc) and to measure the parameters needed to select the energy, the intensity and the Monitor Units (MU) for the exposition: percentage Depth Dose; beam profiles; isodose curves; values of dose per MU. In this work we present the results obtained by using two orthogonal layers of the calorimetric phantom Dosiort, in particular we report the measurement of the dynamic range of the read-out system and the first qualitative study of the results which can be extracted from the measurements taken in a test beam.

Lamanna, E.; Fiorillo, A. S.; Vena, R.; Berdondini, A.; Bettuzzi, M.; Brancaccio, R.; Casali, F.; Morigi, M. P.; Bilokon, H.; Barca, G.; Castrovillari, F.; Siaka, Y. F. T.

2009-12-01

111

Calorimetric particle detectors with superconducting transition edge thermometers  

NASA Astrophysics Data System (ADS)

The cryogenic detector group at the MPI, Munchen, in collaboration with the Technische Universitat Munchen, is developing calorimetric detectors utilizing large absorber crystals coupled to superconducting transition edge thermometers. At low temperature, high energy resolution results from the low detector heat capacity and the strong temperature dependence of the resistance of the thermometer at the normal/superconducting phase transition. The transition edge thermometer is a thin film at very low Tc superconductor deposited directly on the absorber. Results from two detectors yielding excellent energy resolution are presented. One of these detectors was fabricated with an Ir strip thermometer, and the other with an Ir/Au proximity effect bilayer. Detailed studies have resulted in a model which will be used to optimize future detectors.

Dummer, D.

1993-03-01

112

ac-Calorimetric Measurements of Transverse Thermal Conductivity  

NASA Astrophysics Data System (ADS)

We are developing an ac-calorimetric technique, heating one surface of a thin sample with oscillating power and measuring the temperature oscillations on the opposite surface, to measure the thermal conductivity of solids. While the temperature oscillations are inversely proportional to the heat capacity at low frequencies, at higher frequencies the response is limited by the transverse thermal diffusivity. Because of the response times of thermometers and the fact that the magnitude of the temperature oscillation varies inversely with frequency, this technique is most useful for materials with low thermal conductivities, such as the interlayer conductivity in layered materials. We will show results on ``standard'' materials (teflon, sapphire) as well as the layered organic semiconductors, rubrene and TIPS-pentacene.

Zhang, Hao; Brill, Joseph

2013-03-01

113

20 CFR 416.573 - How much will we withhold from your title II and title VIII benefits to recover a title XVI...  

Code of Federal Regulations, 2013 CFR

...your title II and title VIII benefits to recover a title XVI overpayment...Section 416.573 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL...AND DISABLED Payment of Benefits, Overpayments, and...

2013-04-01

114

Experimental M1 transition rates in K XI, K XV, and K XVI  

NASA Astrophysics Data System (ADS)

Transition probabilities of three magnetic dipole (M1) transitions in multiply charged ions of potassium have been measured using the Livermore electron beam ion trap EBIT-2. Our results for the atomic level lifetimes are 4.44+/-0.10 ms for K XI (F-like) 2s22p5 2Po1/2, 4.47+/-0.10 ms for K XV (B-like) 2s22p 2Po3/2, and 7.6+/-0.5 ms for K XVI (Be-like) 2s2p 3Po2. The results confirm the accuracy of most predictions to within 3% of ground-state and 7% of excited-state transitions.

Träbert, E.; Beiersdorfer, P.; Brown, G. V.; Chen, H.; Pinnington, E. H.; Thorn, D. B.

2001-09-01

115

Calorimetric AC loss measurement of MgB2 superconducting tape in an alternating transport current and direct magnetic field  

NASA Astrophysics Data System (ADS)

Applications of MgB2 superconductors in electrical engineering have been widely reported, and various studies have been made to define their alternating current (AC) losses. However, studies on the transport losses with an applied transverse DC magnetic field have not been conducted, even though this is one of the favored conditions in applications of practical MgB2 tapes. Methods and techniques used to characterize and measure these losses have so far been grouped into ‘electrical’ and ‘calorimetric’ approaches with external conditions set to resemble the application conditions. In this paper, we present a new approach to mounting the sample and employ the calorimetric method to accurately determine the losses in the concurrent application of AC transport current and DC magnetic fields that are likely to be experienced in practical devices such as generators and motors. This technique provides great simplification compared to the pickup coil and lock-in amplifier methods and is applied to a long length (˜10 cm) superconducting tape. The AC loss data at 20 and 30 K will be presented in an applied transport current of 50 Hz under external DC magnetic fields. The results are found to be higher than the theoretical predictions because of the metallic fraction of the tape that contributes quite significantly to the total losses. The data, however, will allow minimization of losses in practical MgB2 coils and will be used in the verification of numerical coil models.

See, K. W.; Xu, X.; Horvat, J.; Cook, C. D.; Dou, S. X.

2012-11-01

116

Calorimetric measurements of the ''equivalent series resistance'' of low-loss, high repetition rate pulse discharge capacitors  

SciTech Connect

In high repetition rate pulsed circuits, component losses are a major design consideration. Accurate means of calculating the dissipation loss is essential for determining efficiency and in designing cooling systems for removal of associated heat. In high voltage systems, dielectric loss can be a major contributor to power dissipation. Total energy dissipation in a capacitor is the sum of dielectric, tab, corona, lead connections, and skin effect losses. Dielectric loss is also dependent on temperature, voltage, and frequency which adds to the complexity of determining an accurate value. The total loss component can be described by the ''equivalent series resistance'' or ESR. In this paper we will review the most common electrical methods used to measure the ESR and particulars that must be considered with these techniques. Finally we will describe calorimetric methods of ESR determination that are accurate regardless of frequency and voltage and the ESR values of a variety of commercially available pulsed discharge capacitors.

McDuff, G.G.; Rust, K.R.

1986-01-01

117

Genetic comparison of the head of Henri IV and the presumptive blood from Louis XVI (both Kings of France).  

PubMed

A mummified head was identified in 2010 as belonging to Henri IV, King of France. A putative blood sample from the King Louis XVI preserved into a pyrographically decorated gourd was analyzed in 2011. Both kings are in a direct male-line descent, separated by seven generations. We have retrieved the hypervariable region 1 of the mitochondrial DNA as well as a partial Y-chromosome profile from Henri IV. Five STR loci match the alleles found in Louis XVI, while another locus shows an allele that is just one mutation step apart. Taking into consideration that the partial Y-chromosome profile is extremely rare in modern human databases, we concluded that both males could be paternally related. The likelihood ratio of the two samples belonging to males separated by seven generations (as opposed to unrelated males) was estimated as 246.3, with a 95% confidence interval between 44.2 and 9729. Historically speaking, this forensic DNA data would confirm the identity of the previous Louis XVI sample, and give another positive argument for the authenticity of the head of Henri IV. PMID:23283403

Charlier, Philippe; Olalde, Iñigo; Solé, Neus; Ramírez, Oscar; Babelon, Jean-Pierre; Galland, Bruno; Calafell, Francesc; Lalueza-Fox, Carles

2012-12-30

118

The Calorimetric Glass Transition of Polystyrene Ultrathin Films  

NASA Astrophysics Data System (ADS)

The glass transition temperature (Tg) for nanoconfined materials have been widely studied since the early 1990s. For supported polystyrene ultrathin films, Tg differs from bulk value. Recent work has attributed nanoconstrained Tg effects to artifact. In this study, we attempted to resolve this controversy and measure Tg for single polystyrene ultrathin films using Flash DSC. Films have been prepared in two ways: spincast films placed on a layer of inert oil or grease and films directly spincast on the back of the calorimetric chip. For the films on oil or on grease, the 160 nm thick films show no Tg depression. On the other hand, thinner films on oil and on grease show a Tg depression which decreases with increasing cooling rate. The depression reverts to the bulk values over the course of a day at 160 ^oC due to dewetting and thickening. For directly spincast films, no Tg depression is observed, consistent with results from other nanocalorimetry work. Our results are consistent with literature results that Tg decreases with decreasing substrate surface energy, and they also demonstrate that the Tg depression observed is not due to degradation or to plasticization effects.

Gao, Siyang; Koh, Yung P.; Simon, Sindee S.

2013-03-01

119

XVI European Charcot Foundation Lecture: Nutrition and environment, can MS be prevented?  

PubMed Central

Multiple sclerosis is a relatively common debilitating neurologic disease that affects people in early adulthood. While the characteristic pathology of MS has been well described, the etiology of the disease is not well understood, despite decades of research and the identification of strong genetic and environmental candidates for susceptibility. A question central to all diseases, but posed specifically for MS at the XVI European Charcot Foundation Lecture, was ‘Can MS be prevented?’ To address this question, we have evaluated the available data regarding nutritional and environmental factors that may be related to MS susceptibility and suggest the extent to which a potential intervention may reduce disease burden. It is our opinion that intervention, particularly supplementation with vitamin D, could have a dramatic impact on disease prevalence. Understanding that any intervention or behavioral modification will surely act in the context of genetic susceptibility and unidentified stochastic events, it is likely that not all MS is ‘preventable’. Epidemiologic observation has provided key insights into environmental and nutritional factors that may alter one’s susceptibility to MS, however, there are still many questions in unraveling the etiology of this complex disease.

Simon, Kelly Claire; Munger, Kassandra L; Ascherio, Alberto

2012-01-01

120

Neutron detection by measuring capture gammas in a calorimetric approach  

NASA Astrophysics Data System (ADS)

The neutron capture detector (NCD) is introduced as a novel detection scheme for thermal and epithermal neutrons that could provide large-area neutron counters by using common detector materials and proven technologies. The NCD is based on the fact that neutron captures are usually followed by prompt gamma cascades, where the sum energy of the gammas equals to the total excitation energy of typically 6–9 MeV. This large sum energy is measured in a calorimetric approach and taken as the signature of a neutron capture event. An NCD consists of a neutron converter, comprising of constituents with large elemental neutron capture cross-section like cadmium or gadolinium, which is embedded in common scintillator material. The scintillator must be large and dense enough to absorb with reasonable probability a portion of the sum energy that exceeds the energy of gammas emitted by common (natural, medical, industrial) radiation sources. An energy window, advantageously complemented with a multiplicity filter, then discriminates neutron capture signals against background. The paper presents experimental results obtained at the cold-neutron beam of the BER II research reactor, Helmholtz-Zentrum Berlin, and at other neutron sources with a prototype NCD, consisting of four BGO crystals with embedded cadmium sheets, and with a benchmark configuration consisting of two separate NaI(Tl) detectors. The detector responses are in excellent agreement with predictions of a simulation model developed for optimizing NCD configurations. NCDs could be deployed as neutron detectors in radiation portal monitors (RPMs). Advanced modular scintillation detector systems could even combine neutron and gamma sensitivity with excellent background suppression at minimum overall expense.

Pausch, Guntram; Herbach, Claus-Michael; Kong, Yong; Lentering, Ralf; Plettner, Cristina; Roemer, Katja; Scherwinski, Falko; Stein, Juergen; Schotanus, Paul; Wilpert, Thomas

2011-10-01

121

Religion and the Catholic church's view on (heart) transplantation: a recent statement of Pope Benedict XVI and its practical impact.  

PubMed

Heart transplantation is performed on approximately 4,000 patients per year worldwide and is considered the last resort for treatment of end-stage heart diseases. Due to persistent organ shortage, resources are limited, waiting periods are extensive, and patients still die while being on a waiting list for transplantation. The role of all churches and the support of the representatives of the churches are critical for the spiritual wellbeing of patients awaiting heart transplantation as well as for prospective individual organ donors and their families. The supportive role of the Roman Catholic Church and the recent statement of Pope Benedict XVI on organ donation are discussed. PMID:19784776

Schwarz, Ernst R; Rosanio, Salvatore

2011-09-01

122

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

SciTech Connect

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.

Perry, R.B. [Argonne National Lab., IL (United States). Electronics and Computing Technologies Div.; Zucker, M.S. [Brookhaven National Lab., Upton, NY (United States)

1994-06-01

123

Ti 4+ in silicate melts: Energetics from high-temperature calorimetric studies and implications for melt structure  

NASA Astrophysics Data System (ADS)

The drop solution calorimetric method was used to determine the enthalpy of solution of rutile ( ?Hsol) in silicate melts. High-temperature (1760 K) in situ calorimetric data show that ?Hsol is a strong function of melt composition. For potassium endmember melts, potassium disilicate, and trisilicate, ?Hsol increases (from 28-48 kJ/mol) as TiO 2 concentration increases. For calcium disilicate melts ?Hsol is constant (69 kJ/mol). For mixed potassium-calcium compositions, ?Hsol is more exothermic than for the calcium endmember but remains constant at 43.9 kJ/mol. The enthalpy of solution of rutile at 1760 K and the enthalpy of mixing at 978 K derived from lead borate solution calorimetry for Ti-bearing potassium aluminosilicate glasses have been used to model the homogeneous equilibria among Ti species in the potassium-bearing melts. The energetics of Ti speciation were used to predict quantitatively the excess heat capacity of titanium-bearing silicate melts previously observed by Lange and Navrotsky (1993), suggesting that heat capacities, mixing properties, and rutile solubility are all controlled by the temperature and composition dependence of the same set of homogenous equilibria among titanium species in the melts. Though knowing the exact microscopic nature of these species is not necessary for macroscopic thermodynamic modeling, the model is consistent with a gradual variation with composition and temperature in mid-range order involving five-coordinated titanyl groups and alkali atoms as proposed by Farges et al. (1996a,b,c).

Gan, Hao; Wilding, Martin C.; Navrotsky, Alexandra

1996-11-01

124

Calorimetric apparatus for alternating current loss measurements on high-temperature superconductors  

Microsoft Academic Search

The use of high-temperature superconductors in electric power components requires the knowledge of their alternating current (ac) losses. Methods are therefore needed to characterize the conductors with respect to their ac losses under applicationlike conditions. In this article we describe a calorimetric setup for ac loss measurements on long length high-temperature superconductors carrying ac transport currents in ac external magnetic

N. Magnusson; S. Hörnfeldt

1998-01-01

125

Rheological and calorimetric properties of recycled bisphenol A poly(carbonate)  

Microsoft Academic Search

Mechanical recycling of engineering polycarbonate wastes provides an interesting way to decrease the impact on environment, if the degradation due to successive processing is properly characterized. We analyzed polycarbonate (PC) degradation generated by eight successive recycling, using rheological, calorimetric and colorimetric tools at each step. From the first to the fifth recycling, an increase of storage modulus E? (at T=30 °C

J. F. Feller; A. Bourmaud

2003-01-01

126

Differential scanning calorimetric analysis for monitoring the oxidation of heated oils  

Microsoft Academic Search

A simple and reliable differential scanning calorimetric (DSC) method was developed for monitoring the oxidation in heated oils. Three different types of edible oils, namely, corn oil (CO), refined, bleached and deodorised palm olein (RBDPO) and soybean oil (SO) were used in this study. The DSC method was based on the cooling thermogram of oil samples at a scanning rate

C. P Tan; Y. B Che Man

1999-01-01

127

A Simple Calorimetric Experiment That Highlights Aspects of Global Heat Retention and Global Warming  

Microsoft Academic Search

This report outlines a simple calorimetric experiment for the general chemistry laboratory that illustrates a classic prin- ciple of chemical thermodynamics and, in a somewhat novel way, gives students an introduction to some broad features associated with global heat retention and global warming. The earth has had a robust greenhouse warming effect for mil- lions of years; otherwise the planet

Joel D. Burley; Harold S. Johnston

2007-01-01

128

A high pressure calorimetric experiment to validate the liquid-liquid critical point hypothesis in water  

Microsoft Academic Search

An experimental proposal to test the existence of a liquid-liquid critical point in water, based on high pressure calorimetric measurements, is presented on this paper. Considering the existence of an intramolecular correlation in the water molecule we show how the response of the specific heat at high pressure is different depending on the existence, or not, of the second critical

Manuel I. Marques

2007-01-01

129

Thermal explosion analysis of methyl ethyl ketone peroxide by non-isothermal and isothermal calorimetric applications  

Microsoft Academic Search

In the past, process incidents attributed to organic peroxides (OPs) that involved near misses, over-pressures, runaway reactions, and thermal explosions occurred because of poor training, human error, incorrect kinetic assumptions, insufficient change management, and inadequate chemical knowledge in the manufacturing process. Calorimetric applications were employed broadly to test organic peroxides on a small-scale because of their thermal hazards, such as

Jen-Hao Chi; Sheng-Hung Wu; Chi-Min Shu

2009-01-01

130

Calorimetric control for high cell density cultivation of a recombinant Escherichia coli strain  

Microsoft Academic Search

In order to achieve maximum productivity of recombinant proteins in Escherichia coli high cell density cultivation (HCDC) strategies have been the subject of many studies. The aim of this work was the application of calorimetric methods to HCDC. The specific growth rate of a recombinant E. coli strain producing green fluorescent protein (GFP) was controlled during fed-batch cultivations by estimating

Richard Biener; Anne Steinkämper; Johannes Hofmann

2010-01-01

131

Energetics of carbohydrate binding to Momordica charantia (bitter gourd) lectin: an isothermal titration calorimetric study.  

PubMed

Physico-chemical and carbohydrate binding studies have been carried out on the Momordica charantia (bitter gourd) seed lectin (MCL). The lectin activity is maximal in the pH range 7.4-11.0, but decreases steeply below pH 7.0. The lectin activity is mostly unaffected in the temperature range 4-50 degrees C, but a sharp decrease is seen between 50 and 60 degrees C, which could be correlated to changes in the structure of the protein as seen by circular dichroism and fluorescence spectroscopy. Isothermal titration calorimetric studies show that the tetrameric MCL binds two sugar molecules and the binding constants (Kb), determined at 288.15 K, for various saccharides were found to vary between 7.3 x 10(3) and 1.52 x 10(4)M(-1). The binding reactions for all the saccharides investigated were essentially enthalpy driven, with the binding enthalpies (DeltaHb) at 288.15 K being in the range of -50.99 and -43.39 kJ mol(-1), whereas the contribution to the binding reaction from the entropy of binding was negative, with values of binding entropy (DeltaSb) ranging between -99.2 and -72.0 J mol(-1)K(-1) at 288.15 K. Changes in heat capacity (DeltaCp) for the binding of disaccharides, lactose and lactulose, were significantly larger in magnitude than those obtained for the monosaccharides, methyl-beta-D-galactopyranoside, and methyl-alpha-D-galactopyranoside, and could be correlated reasonably well with the surface areas of these ligands. Enthalpy-entropy compensation was observed for all the sugars studied, suggesting that water structure plays an important role in the overall binding reaction. CD spectroscopy indicates that carbohydrate binding does not lead to significant changes in the secondary and tertiary structures of MCL, suggesting that the carbohydrate binding sites on this lectin are mostly preformed. PMID:15820223

Sultan, Nabil Ali Mohammed; Swamy, Musti J

2005-05-01

132

[Menarche, menstrual and sociodemographic characteristics of Puerto Rican female athletes in the XV and XVI Central American and Caribbean Games].  

PubMed

This investigation described maturation, menstrual and socio-demographic characteristics of 65 Puerto Rican women athletes that were interviewed during the XVI Central American and Caribbean Games (CACG), Mexico City in 1990. The results were compared with those of Puerto Rican women athletes (n = 52) at the XV CACG, Santiago Dominican Republic, 1986. The quantitative variables (age, age at initiation of training, years of training, age at menarche, birth order, and family size) were not statistically different (t-independent, p > or = 0.05). The observed frequencies for the qualitative variables (menstrual characteristics, degree of certainty in the recall of age of menarche, use of oral contraceptives, and marital status) were very similar. In conclusion: the women at the XVI CAC in Mexico demonstrated similar maturational, menstrual and socio-demographic characteristics to the those athletes evaluated four years earlier in Santiago and based on their long history of training, both samples were representative of athletically mature athletes. The findings were very similar to those reported for olympic athletes and such data expands the available information on Puerto Rican women athletes. PMID:8272482

Rivera, M A; Mendez Zamora, I; Matos, R M; Rivera, A

1993-09-01

133

LA PROBLEMÁTICA DE LA CLASIFICACIÓN DE LA CONSONANCIA EN EL SIGLO XVI Y LA TEORÍA DE LA CONSONANCIA DE FRANCISCO SALINAS  

Microsoft Academic Search

A mediados del siglo XVI nos encontramos con una clasificación de los intervalos consonantes más o menos admitida por todos los teóricos del momento: son consonancias perfectas la octava, la quinta y la cuarta, mientras que son consonancias imperfectas las terceras y las sextas. Zarlino incluso desarrolla un marco metafísico (el numero senario) de explicación de la consonancia que intenta

Amaya Sara García Pérez

2003-01-01

134

Analysis of Methods of Determining Losses of Fuel Due to Mechanical Incompleteness of Combustion.  

National Technical Information Service (NTIS)

Consideration is given to the effectiveness of various optical, calorimetric, mechanical, and chemical methods for determining the magnitude of losses due to mechanical incompleteness of combustion in furnace devices.

L. V. Kulagin K. F. Dobrikov S. S. Okhotnikov

1966-01-01

135

Identifying the critical point of the weakly first-order itinerant magnet DyCo2 with complementary magnetization and calorimetric measurements  

NASA Astrophysics Data System (ADS)

We examine the character of the itinerant magnetic transition of DyCo2 by different calorimetric methods, thereby separating the heat capacity and latent heat contributions to the entropy—allowing direct comparison to other itinerant electron metamagnetic systems. The heat capacity exhibits a large ?-like peak at the ferrimagnetic ordering phase transition, a signature that is remarkably similar to La(Fe,Si)13, where it is attributed to giant spin fluctuations. Using calorimetric measurements, we also determine the point at which the phase transition ceases to be first order: the critical magnetic field, ?0Hcrit = 0.4 ± 0.1 T and temperature Tcrit = 138.5 ± 0.5 K, and we compare these values to those obtained from analysis of magnetization by application of the Shimizu inequality for itinerant electron metamagnetism. Good agreement is found between these independent measurements, thus establishing the phase diagram and critical point with some confidence. In addition, we find that the often-used Banerjee criterion may not be suitable for determination of first order behavior in itinerant magnet systems.

Morrison, K.; Dupas, A.; Mudryk, Y.; Pecharsky, V. K.; Gschneidner, K. A.; Caplin, A. D.; Cohen, L. F.

2013-04-01

136

Calorimetric effects during the ? ? ? transformation in Fe-Ni-Ti metastable alloys  

NASA Astrophysics Data System (ADS)

A calorimetric study of the reverse ? ? ? transformation has been carried out in five metastable Fe-Ni-Ti alloys. The amount of the ? phase in the initial samples is more than 50%. The exothermic processes of the decomposition of the ? and ? phases exceed the endothermic reactions of formation of the reverted austenite upon heating to the midpoint of the temperature interval of the reverse ? ? ? transformation. In the middle part of the interval in which the maximum rate of the transformation is recorded by the magnetometric method, the calorimetric curve does not exhibit thermal effects. This disagreement indicates the complex character of the transformation. At the finishing stage of the ? ? ? transformation, there is clearly detected an endothermic reaction.

Zemtsova, N. D.; Eremina, M. A.; Zavalishin, V. A.

2012-05-01

137

Positron annihilation and differential scanning calorimetric study of poly(trimethylene terephthalate)\\/EPDM blends  

Microsoft Academic Search

The blends of poly(trimethylene terephthalate) (PTT) and ethylene propylene diene monomer (EPDM) with different composition have been studied by positron lifetime technique (PLT) and differential scanning calorimetric (DSC) measurements. The DSC results for the blends of 50\\/50 and 40\\/60 show clear two glass transition temperatures indicating two-phase system. No melting point depression was observed for the blend system, which strongly

H. B. Ravikumar; C. Ranganathaiah; G. N. Kumaraswamy; S. Thomas

2005-01-01

138

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

Microsoft Academic Search

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

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

1992-01-01

139

Temperature-modulated differential scanning calorimetric measurements on nascent ultra-high molecular mass polyethylene  

Microsoft Academic Search

Temperature-modulated differential scanning calorimetric (TMDSC) measurements on nascent ultra-high molecular mass polyethylene (UHMMPE) in scanning as well as quasi-isothermal mode are presented. From these measurements, a special irreversible relaxation process in the pre-melting region can be separated, which only occur on the first heating of the nascent material. The frequency dependence of this process yield a characteristic time constant of

G. W. H. Höhne; L. Kurelec

2001-01-01

140

Test results of an apparatus for calorimetric measurement of AC losses in superconductors  

Microsoft Academic Search

A description is given of a novel method to measure calorimetrically AC losses in superconducting samples. The boil-off gas is stored below the liquid helium level in a measuring tube. Losses in the range of 1 mW up to 100 mW can be measured with an accuracy of 3%. Results of measurements of AC losses in superconducting wires are presented.

J. A. Eikelboom

1992-01-01

141

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

SciTech Connect

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.

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

1999-04-05

142

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

SciTech Connect

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.

Cremers, Teresa L [Los Alamos National Laboratory; Sampson, Thomas E [Los Alamos National Laboratory

2010-01-01

143

Calorimetric and spectroscopic studies of aminoglycoside binding to AT-rich DNA triple helices.  

PubMed

Calorimetric and fluorescence techniques were used to characterize the binding of aminoglycosides-neomycin, paromomycin, and ribostamycin, with 5'-dA(12)-x-dT(12)-x-dT(12)-3' intramolecular DNA triplex (x = hexaethylene glycol) and poly(dA).2poly(dT) triplex. Our results demonstrate the following features: (1) UV thermal analysis reveals that the T(m) for triplex decreases with increasing pH value in the presence of neomycin, while the T(m) for the duplex remains unchanged. (2) The binding affinity of neomycin decreases with increased pH, although there is an increase in observed binding enthalpy. (3) ITC studies conducted in two buffers (sodium cacodylate and MOPS) yield the number of protonated drug amino groups (Deltan) as 0.29 and 0.40 for neomycin and paromomycin interaction with 5'-dA(12)-x-dT(12)-x-dT(12)-3', respectively. (4) The specific heat capacity change (DeltaC(p)) determined by ITC studies is negative, with more negative values at lower salt concentrations. From 100 mM to 250 mM KCl, the DeltaC(p) ranges from -402 to -60 cal/(mol K) for neomycin. At pH 5.5, a more positive DeltaC(p) is observed, with a value of -98 cal/(mol K) at 100 mM KCl. DeltaC(p) is not significantly affected by ionic strength. (5) Salt dependence studies reveal that there are at least three amino groups of neomycin participating in the electrostatic interactions with the triplex. (6) FID studies using thiazole orange were used to derive the AC(50) (aminoglycoside concentration needed to displace 50% of the dye from the triplex) values. Neomycin shows a seven fold higher affinity than paromomycin and eleven fold higher affinity than ribostamycin at pH 6.8. (7) Modeling studies, consistent with UV and ITC results, show the importance of an additional positive charge in triplex recognition by neomycin. The modeling and thermodynamic studies indicate that neomycin binding to the DNA triplex depends upon significant contributions from charge as well as shape complementarity of the drug to the DNA triplex Watson-Hoogsteen groove. PMID:20167243

Xi, Hongjuan; Kumar, Sunil; Dosen-Micovic, Ljiljana; Arya, Dev P

2010-02-16

144

Binding of lanthanum and gadolinium ions to concanavalin A studied calorimetrically at 25 degrees C.  

PubMed

The interaction between Concanavalin A (ConA) and the lanthanide ions La3+ and Gd3+ has been studied calorimetrically at 25 degrees C. The measurements were carried out at a pH of 4.5, where the protein exists prevailingly as a dimer. Calorimetry allows the direct determination of the binding enthalpy and the evaluation of both the apparent association constant, and the apparent free energy and entropy. Three groups of data were collected. The first concerns the interaction of the 'native' protein, i.e., fully metallized with Mn2+ and Ca2+, with the lanthanides. The second concerns the interaction of the completely demetallized protein with La3+ and Gd3+. Finally, the affinity of each complex was tested for the specific sugar alpha-methylmannopyranoside. The analysis of the thermodynamic parameters obtained, led to the following conclusions: 1) a specific site, named S3, exists on the protein for the lanthanides, distinct from the S1 site of the transition metal and from the S2 site, specific for calcium. There is only one S3 site per protomer when the protein has Mn2+ in S1 and Ca2+ in S2. Moreover, there is no appreciable competition for S1 and S2 from the lanthanides. The 'native' protein, metallized with La3+ or Gd3+, is a fully functional protein. 2) The demetallized protein (ApoCon A) has at least two sites per protomer for the lanthanides. The hypothesis is that, besides the S3 site, the lanthanides, in the absence of Mn2+, can also occupy the S1, but not the S2, site. The protein metallized only with gadolinium ion is completely inactive toward the interaction with the mannoside. The same happens when, along with gadolinium, only calcium or manganese is present. Hence, in the absence of the transition metal in S1 or of calcium in S2, the protein is not in the conformation suitable to interact with its specific substrate. PMID:2637041

Barone, G; Castronuovo, G; Del Vecchio, P; Elia, V; Guarrata, P

1989-12-01

145

Calorimetric method for arensic in coal. [Microgram amounts  

Microsoft Academic Search

A chemical method of determining microgram quantities of arsenic in coal was investigated by the Bureau of Mines to supplement a semiquantitative spectrographic method of determining arsenic in coal ash. In accordance with a method recommended by the International Organization for Standardization, 1-gram samples of coal are decomposed by wet oxidation with boiling sulfuric acid (HâSOâ) and nitric acid (HNOâ)

R. F. Abernethy; F. H. Gibson

1968-01-01

146

Measurement and Modeling of Inner-Shell Satellites of Na-like Fe XVI between 14.5 ?A and 18 ?A  

SciTech Connect

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.

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

2007-09-10

147

Wavelengths, classifications, and ionization energies in the isoelectronic sequences from Yb II and Yb III through Bi XV and Bi XVI  

Microsoft Academic Search

Spectral observations are reported for transitions to the ground term and first excited term of the one-electron configurations in the 4f¹⁴5p⁶nl isoelectronic sequence from Yb II through Bi XV. Resonance lines are reported for the isoelectronic sequence Yb III through Bi XVI in which the ground state is 4f¹⁴5p⁶ ¹Sâ and the upper levels are the J = 1 levels

Victor Kaufman; Jack Sugar

1976-01-01

148

Complexation of manganese(II) by cyclohexano-15-crown-5 in propylene carbonate: Calorimetric and X-ray crystallographic investigation  

SciTech Connect

Calorimetric titrimetry reveals that cyclohexano-15-crown-5 (C15C5) forms a 1:1 complex with Mn(II) ions (2.5 mM) in propylene carbonate (PC) solution to which was added levels of water up to 134 mM. The reaction proceeds with a strong driving force (log K = 4.7-5.0) and is enthalpically driven overall, but the magnitude of the enthalpy change decreases with increasing water concentration in the case of the Mn(II) nitrate salt. A minor anion effect occurs in which the trifluoromethansulfonate ion gives slightly more negative values of {Delta}H and T{Delta}S than the nitrate ion. Values of log K, however, do not change appreciably with increasing water concentration, nor are they dependent on the anion. The crystal structure of Mn(C15C5)(CF{sub 3}SO{sub 3}){sub 2} was determined, showing that the Mn(II) ion is coordinated by a pentagonal bipyramid of oxygen atoms provided by the equatorial crown {Angstrom}, b=14.145(1) {Angstrom}, c = 13,420(1) {Angstrom} {beta} = 100.31(2){degrees}, V = 5028 {Angstrom}{sup 3}, Z = 8, t = 26 {degrees}C. For 2178 reflections with I > {sigma}(I), and 325 parameters, R(F) = 0.050 and R{sub w}(F) = 0.054.

Deng, Yanpei; Burns, J.H.; Moyer, B.A. [Oak Ridge National Lab., TN (United States)

1995-01-04

149

Calorimetric Low Temperature Detectors for High Resolution X-ray Spectroscopy on Stored Highly Stripped Heavy Ions  

SciTech Connect

The precise determination of the Lamb shift in heavy hydrogen-like ions provides a sensitive test of QED in very strong Coulomb fields, not accessible otherwise, and has also the potential to deduce nuclear charge radii. A brief overview on the present status of such experiments, performed at the storage ring ESR at GSI Darmstadt, is given. For the investigation of the Lyman-{alpha} transitions in Au{sup 78+} or U{sup 91+} ions with improved accuracy, a high-resolution calorimetric low-temperature detector for hard x-rays (E {le} 100 keV) has been recently developed. The detector modules consist of arrays of silicon thermistors and of x-ray absorbers made of high-Z material to optimize the absorption efficiency. The detectors are housed in a specially designed {sup 3}He/{sup 4}He dilution refrigerator which fits to the geometry of the ESR target. The detector performance presently achieved is already close to fulfilling the demands of the Lamb shift experiment. For a prototype detector an energy resolution of {Delta}E{sub FWHM} = 75 eV is obtained for 60-keV x-rays.

Bleile, A.; Egelhof, P.; Kluge, H.J.; Liebisch, U.; McCammon, D.; Meier, H.J.; Sebastian, O.; Stahle, C.K.; Stoehlker, T.; Weber, M.

2000-12-31

150

Calorimetric investigation of the magnetocaloric effect in Ni45Co5Mn37.5In12.5  

NASA Astrophysics Data System (ADS)

A calorimetric investigation of a Ni45Co5Mn37.5In12.5 single crystal has been carried out by combining differential scanning calorimetry (DSC) and heat capacity (C) measurements. The martensitic transition showing a first-order character spread over a wide temperature range, a specific measuring technique of C(T) has been developed. This method—based on a time-resolved analysis of successive heating pulses—was found to yield an entropy change at the transition (?Str) that is very close to that derived from DSC. To investigate the magnetocaloric effect, both the isothermal entropy change ?ST and the adiabatic temperature change ?Tad were derived from heat capacity curves recorded in a series of magnetic fields up to 7 T. The maximum values of ?ST(T, B) were observed to be in accordance with those determined from the Maxwell equation. Furthermore, maximum values of ?Tad(T, B) resulting from the application of 2 T, 5 T and 7 T were found to be equal to -2.3 K, -6.1 K and -9.4 K, respectively.

Guillou, F.; Courtois, P.; Porcar, L.; Plaindoux, P.; Bourgault, D.; Hardy, V.

2012-06-01

151

High-accuracy MR-MP Perturbation Theory Energy and Radiative Rates Calculations for Core-excited Transitions in Fe XVI  

NASA Astrophysics Data System (ADS)

Accurate theoretical energy level, lifetime, and transition probability calculations of core-excited Fe XVI were performed employing the relativistic Multireference Møller-Plesset perturbation theory. In these computations the term energies of the highly excited n <= 5 states arising from the configuration 1s 22sk 2pm 3l p nl' q , where k + m + p + q = 9, l <= 3 and p + q <= 2 are considered, including those of the autoionizing levels with a hole-state in the L-shell. All even and odd parity states of sodium-like iron ion were included for a total of 1784 levels. Comparison of the calculated L-shell transition wavelengths with those from laboratory measurements shows excellent agreement. Therefore, our calculation may be used to predict the wavelengths of as of yet unobserved Fe XVI, such as the second strongest 2p-3d Fe XVI line, which has not been directly observed in the laboratory and which blends with one of the prominent Fe XVII lines.

Díaz, F.; Vilkas, M. J.; Ishikawa, Y.; Beiersdorfer, P.

2013-07-01

152

OVERVIEW OF CALORIMETRIC ASSAY OF PLUTONIUM IN THE UNITED STATES  

SciTech Connect

Calorimetry is a primary measurement technique for assay of quantities of plutonium in the United States. It is the most accurate NDA technique for many forms of plutonium-bearing materials. This paper provides an overview of the use of calorimetry in combination with high-resolution gamma-ray spectroscopy for accurate plutonium mass determinations.

Rudy, C. R. (Clifford R.)

2001-01-01

153

A calorimetric study of the thermodynamic properties of potassium molybdate  

NASA Astrophysics Data System (ADS)

The low-temperature heat capacity of K2MoO4 was measured by adiabatic calorimetry. The smoothed heat capacity values, entropies, reduced Gibbs energies, and enthalpies were calculated over the temperature range 0-330 K. The standard thermodynamic functions determined at 298.15 K were C {/p °} (298.15 K) = 143.1 ± 0.2 J/(mol K), S°(298.15 K) = 199.3 ± 0.4 J/(mol K), H°(298.15 K)- H°(0) = 28.41 ± 0.03 kJ/mol, and ?°(298.15 K) = 104.0 ± 0.4 J/(mol K). The thermal behavior of potassium molybdate at elevated temperatures was studied by differential scanning calorimetry. The parameters of polymorphic transitions and fusion of potassium molybdate were determined.

Gavrichev, K. S.; Ryumin, M. A.; Tyurin, A. V.; Gurevich, V. M.; Komissarova, L. N.; Khoroshilov, A. V.; Sharpataya, G. A.

2009-03-01

154

Differential scanning calorimetric studies of a Bacillus halodurans ?-amylase  

Microsoft Academic Search

The thermal unfolding of Amy 34, a recombinant ?-amylase from Bacillus halodurans, has been investigated using differential scanning calorimetry (DSC). The denaturation of Amy 34 involves irreversible processes with an apparent denaturation temperature (Tm) of 70.8 °C at pH 9.0, with four transitions, as determined using multiple Gaussian curves. The Tm increased by 5 °C in the presence of 100-fold

Suhaila O. Hashim; Rajni-Hatti Kaul; Maria Andersson; Francis J. Mulaa; Bo Mattiasson

2005-01-01

155

Calorimetric study of the conformational relaxation times in polystyrene  

Microsoft Academic Search

The temperature dependence of the relaxation times of the structural relaxation process of polystyrene is determined by temperature-modulated\\u000a differential scanning calorimetry (TMDSC) and by conventional differential scanning calorimetry (DSC) in the latter by modelling\\u000a the experimental heat capacity curves measured in heating scans after different thermal histories. The good agreement between\\u000a both measuring techniques in the temperature interval just above

M. Salmerón; C. Torregrosa; A. Vidaurre; J. M. Meseguer Dueñas; M. Monleón Pradas; J. L. Gómez Ribelles

1999-01-01

156

Calorimetric studies of removal of nonsteroidal anti-inflammatory drugs diclofenac and dipyrone from water  

Microsoft Academic Search

Chitosan microspheres were applied to remove the pollutants diclofenac and dipyrone from water. Adsorption studies were adjusted\\u000a to Langmuir equation. The maximum number of adsorbed moles gave 5.25 × 10?4 and 4.83 × 10?4 mol of diclofenac and dipyrone, respectively, per gram of chitosan microspheres. The interactions in solid\\/liquid interface\\u000a were calorimetrically followed and gave endothermic values: +22.1 ± 1.3 and +48.7 ± 1.5 kJ mol?1, respectively, for the same sequence.

Thiago O. Carvalho; Ana E. B. Matias; Lilian R. Braga; Sheila M. Evangelista; Alexandre G. S. Prado

157

Solid-liquid phase diagrams of binary aromatic hydrocarbon mixtures from calorimetric studies  

SciTech Connect

The authors describe solid-liquid phase diagrams of binary mixtures of aromatic hydrocarbons obtained from calorimetric studies. The sample of the binary solid mixture is heated at a constant rate until the solid is completely melted. During that process, the heat flux needed is monitored. By examination of the curves of the heat flux versus temperature, the solid-liquid phase diagrams can be constructed. Three binary systems (fluorene-dibenzofuran, dibenzothiophene-dibenzofuran, fluorene-dibenzothiophene) have been studied. It turns out that the fluorene-dibenzofuran system forms a solid solution at any composition, while dibenzothiphene-dibenzofuran and fluorene-dibenzothiophene systems have immiscibility gaps in the solid phases.

Sediawan, W.B.; Gupta, S.; McLaughlin, E. (Louisiana State Univ., Baton Rouge, LA (USA). Dept. of Chemical Engineering)

1989-04-01

158

Analysis of Specific Heat Data for Zinc. Resolution of the Calorimetric and Elastic Theta0 Discrepancy  

Microsoft Academic Search

The low-temperature heat capacity of zinc (in the normal state) has been expressed by Cv=?T+?T3+?T5 over the range from 0.15°K to about 8°K. The new parameters obtained are: ?=1.56×10—4 cal\\/deg2 mole, ?=1.39×10—5 cal\\/deg4 mole, and ?=2.44×10—7 cal\\/deg6 mole. The calorimetric Debye temperature, &THgr;0C, is found to be 322°K which is in reasonable agreement with the elastic value, &THgr;0E, of 328°K.

C. W. Garland; J. Silverman

1961-01-01

159

Calorimetric measurements of the ternary Ag–Au–Sn system  

Microsoft Academic Search

Using a Calvet type calorimeter, the enthalpy of mixing in the ternary system Ag–Au–Sn was determined at 873 and at 1023K. The investigations were carried out at three cross-sections with constant molar ratios of Ag:Sn=1:1, 1:2, and 1:9 at 873K, and at four cross-sections with constant molar ratios of Ag:Sn=2:1, 1:1, 1:2, and 1:9 with Au added in the concentration

Z. Li; M. Dallegri; S. Knott

2008-01-01

160

Calorimetric study on magnetism of ErCo2  

NASA Astrophysics Data System (ADS)

Specific heat of ErCo2 was measured in the temperature range 13 to 300 K. A sharp peak was observed at 32 K associated with a first order phase transition. The crystal field contribution to the specific heat was evaluated and crystal parameters were determined in both ferrimagnetic and paramagnetic regions. The saturation value of the magnetic entropy is quite close to R ln(2J + 1) = 23.1 (J/K mol), indicating negligibly small contribution of the Co moment. An entropy discontinuity at Tc can be understood by a sudden change of the ground state degeneracy.

Imai, H.; Wada, H.; Shiga, M.

1995-02-01

161

Cooling history of water-rich tube pumice: a calorimetric determination  

NASA Astrophysics Data System (ADS)

8.7Ma tube pumice from the Ramadas caldera is remarkable for its preservation and for the kinematics preserved within it. Ramadas tube pumice offers potential insights into the physical conditions surrounding the eruptions that generate such pyroclasts. For these reasons it has been chosen for neutron tomographic investigation (Hess et al., this meeting). The thermal history accompanying explosive eruptions is one of their most poorly constrained attributes. In principle, many possible thermal paths exist for these violent and explosive events. Pristine volcanic glass preserved in the eruptive products of such eruptions provides, in principle, information on the physicochemical conditions of such events. Relaxational geospeedometry in particular, can be used to obtain cooling history data for volcanic glass. 8.7Ma tube pumice of the Ramadas has been successfully subjected to enthalpy relaxational geospeedometry. Scanning calorimetry reveals a very low glass transition temperature of ca. 375°C. This value is consistent with the high water contents preserved in this tube pumice (2.9-4.3 wt.%) and suggests a relatively slow cooling across the glass transition of ca. 0.001K/sec. Estimates of bubble relaxation following elongational flow are being made in order to compare the potential timespan for post-fragmentation annealing. The issue of whether the fragmentation conditions correspond to significantly higher temperatures, or to those recorded here, will be explored.

Dingwell, D. B.; Richard, D.; Marti, J.

2009-12-01

162

Calorimetric determination of the heat of combustion of spent Green River shale at 978 K  

SciTech Connect

A Calvet-type calorimeter was used to measure heats of combustion of spent Colorado oil shales. For Green River shale, the samples were members of a sink-float series spanning oil yields from 87 to 340 L . tonne/sup -1/. Shale samples (30-200 mg) are dropped into the calorimeter at high temperature, and a peak in the thermopile signal records the total enthalpy change of the sample between room temperature and the final temperature. Duplicate samples from the above sink-float series were first retorted at 773 K and then dropped separately into nitrogen and oxygen at 978 K. The resulting heats are subtracted to give the heat of combustion, and the results are compared to values from classical bomb calorimetry. The agreement shows that the heats of combustion of the organic component are well understood but that question remain on the reactions of the mineral components.

Mraw, S.C.; Keweshan, C.F.

1987-08-01

163

Calorimetric method for the determination of Curie temperatures of magnetic nanoparticles in dispersion  

Microsoft Academic Search

MnxZn1-xFe2O4-based magnetic fluids with x = 0.1-0.9 are synthesized by coprecipitation. The samples are heated in a radio frequency (rf) magnetic field using an rf generator at different powers, and the temperature is measured as function of time using an optical thermometer. The heating effect of the dispersed magnetic nanoparticles is proportional to the imaginary part of the dynamic magnetic

V. Nica; H. M. Sauer; J. Embs; R. Hempelmann

2008-01-01

164

Calorimetric Study of Kinetic Glass Transition in Metallic Glasses  

SciTech Connect

Differential scanning calorimetry (DSC) experiments were carried out for a bulk metallic glass (BMG), Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10.0}Be{sub 22.5}, below and above the glass transition temperature T{sub g}. The T{sub g} values were determined from the DSC curves. A wide range of heating rate, q = dT/dt = 0.1-100 K/min, was adopted for the experiment, and the q dependence of the apparent T{sub g} was investigated. As q was decreased, the value of T{sub g} decreased rapidly, then more slowly, and seemed to approach a constant value at low q. The experimental result of this kinetic glass transition phenomenon was analyzed on the basis of the relaxation process occurring in the transition temperature range.

Hiki, Y. [Faculty of Science, Tokyo Institute of Technology, 39-3-303 Motoyoyogi, Shibuya-ku, Tokyo 151-0062 (Japan); Takahashi, H. [Institute of Applied Beam Science, Graduate School of Science and Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi 316-8511 (Japan)

2008-02-21

165

2- and 3-acetylpyrroles: a combined calorimetric and computational study.  

PubMed

A combined experimental and computational study on the thermochemistry of 2- and 3-acetylpyrroles was performed. The enthalpies of combustion and sublimation were measured by static bomb combustion calorimetry and Knudsen effusion mass-loss technique, respectively, and the standard (p(o) = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, were determined. Additionally, the gas-phase enthalpies of formation were estimated by G3(MP2)//B3LYP calculations, using several gas-phase working reactions, and were compared with the experimental ones. N-H bond dissociation enthalpies, gas-phase acidities and basicities, proton and electron affinities and ionization enthalpies were also calculated. Experimental and theoretical results are in good agreement and show that 2-acetylpyrrole is thermodynamically more stable than the 3-isomer. The substituent effects of the acetyl group in pyrrole, thiophene and pyridine rings were also analyzed. PMID:19320446

Santos, Ana Filipa L O M; Gomes, José R B; da Silva, Manuel A V Ribeiro

2009-04-16

166

Thermochemistry of 2- and 3-acetylthiophenes: calorimetric and computational study.  

PubMed

The relative stabilities of 2- and 3-acetylthiophenes have been evaluated by experimental thermochemistry and the results compared to high-level ab initio calculations. The enthalpies of combustion, vaporization, and sublimation were measured by rotating-bomb combustion calorimetry, Calvet microcalorimetry, correlation gas chromatography, and Knudsen effusion techniques and the gas-phase enthalpies of formation, at T = 298.15 K, were determined. Standard ab initio molecular orbital calculations at the G2 and G3 levels were performed, and a theoretical study on the molecular and electronic structures of the compounds studied has been conducted. Calculated enthalpies of formation using atomization and isodesmic reactions are compared with the experimental data. Experimental and theoretical results show that 2-acetylthiophene is thermodynamically more stable than the 3-isomer. A comparison of the substituent effect of the acetyl group in benzene and thiophene rings has been carried out. PMID:17918809

Roux, María Victoria; Temprado, Manuel; Jiménez, Pilar; Notario, Rafael; Chickos, James S; Santos, Ana Filipa L O M; da Silva, Manuel A V Ribeiro

2007-10-05

167

Measurement And Modeling Of Fe VIII To Fe XVI M-shell Emission In The Extreme Ultraviolet  

NASA Astrophysics Data System (ADS)

The solar EUV emission near 200 Å is presently being studied with high resolution with the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS), which focuses on the emission between 90 and 270 Å, and with the EUV Imaging Spectrometer on Hinode, which focuses on the region 180 to 204 Å and 250 to 290 Å. The Solar EUV Experiment on the TIMED spacecraft also observes this spectral band but with greatly reduced resolution. The spectrum in this region is dominated by emission from moderate charge states of iron. The interpretation of the data relies on accurate and complete plasma emission models, notably CHIANTI. We have performed a series of laboratory measurements of the 3-3 emission from M-shell iron ions. The measurements cover the range 170 - 250 Å and are made at an electron density of about 1011 cm-3. Emission from Fe VIII through Fe XVI has been identified. Excellent agreement with CHIANTI predictions is found. A few weak transitions are noted in the laboratory data that are predicted by CHIANTI to be vanishingly small and should not have been observed. These are tentatively attributed to transitions in Fe XV. A comparison with observations from CHIPS is also presented. This work was supported in part by NASA's Solar and Heliospheric Physics Supporting Research and Technology Program. Work at UC-LLNL was performed under the auspices of the DOE by under Contract W-7405-Eng-48.

Beiersdorfer, Peter; Lepson, J. K.; Hurwitz, M.

2007-05-01

168

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

PubMed Central

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.

Gentili, Rodolfo; Gentili, Elio; Sgorbati, Sergio

2009-01-01

169

Calorimetric studies of freeze-induced dehydration of phospholipids.  

PubMed

Differential scanning calorimetry (DSC) was used to determine the amount of water that freezes in an aqueous suspension of multilamellar dipalmitoylphosphatidylcholine (DPPC) liposomes. The studies were performed with dehydrated suspensions (12-20 wt% water) and suspensions containing an excess of water (30-70 wt% water). For suspensions that contained > or = 18 wt% water, two ice-formation events were observed during cooling. The first was attributed to heterogeneous nucleation of extraliposomal ice; the second was attributed to homogeneous nucleation of ice within the liposomes. In suspensions with an initial water concentration between 13 and 16 wt%, ice formation occurred only after homogeneous nucleation at temperatures below -40 degrees C. In suspensions containing < 13 wt% water, ice formation during cooling was undetectable by DSC, however, an endotherm resulting from ice melting during warming was observed in suspensions containing > or = 12 wt% water. In suspensions containing < 12 wt% water, an endotherm corresponding to the melting of ice was not observed during warming. The amount of ice that formed in the suspensions was determined by using an improved procedure to calculate the partial area of the endotherm resulting from the melting of ice during warming. The results show that a substantial proportion of water associated with the polar headgroup of phosphatidylcholine can be removed by freeze-induced dehydration, but the amount of ice depends on the thermal history of the samples. For example, after cooling to -100 degrees C at rates > or = 10 degrees C/min, a portion of water in the suspension remains supercooled because of a decrease in the diffusion rate of water with decreasing temperature. A portion of this supercooled water can be frozen during subsequent freeze-induced dehydration of the liposomes under isothermal conditions at subfreezing storage temperature Ts. During isothermal storage at Ts > or = -40 degrees C, the amount of unfrozen water decreased with decreasing Ts and increasing time of storage. After 30 min of storage at Ts = -40 degrees C and subsequent cooling to -100 degrees C, the amount of water associated with the polar headgroups was < 0.1 g/g of DPPC. At temperatures > -50 degrees C, the amount of unfrozen water associated with the polar headgroups of DPPC decreased with decreasing temperature in a manner predicted from the desorption isotherm of DPPC. However, at lower temperatures, the amount of unfrozen water remained constant, in large part, because the unfrozen water underwent a liquid-to-glass transformation at a temperature between -50 degrees and -140 degrees C. PMID:8298015

Bronshteyn, V L; Steponkus, P L

1993-11-01

170

Thermodynamic properties by non-calorimetric methods: Progress report  

NASA Astrophysics Data System (ADS)

This project for the Office of Energy Research focuses on the noncalorimetric determination of thermodynamic properties of polynuclear aromatic molecules through the extension of existing correlation methodologies and through molecular spectroscopy with statistical mechanics. This report highlights progress during the first third of the contract period. Important advances include: derivation of group-contribution parameters for estimation of thermodynamic properties for polycyclic hydrocarbon and nitrogen-containing compounds; calculation of thermodynamic properties for eight key monocyclic compounds based on new and literature spectra were completed for the derivation of 'ring- correction' property estimation parameters; design and construction of a long pathlength, far-infrared sample cell for the collection of vapor-phase spectra of low vapor-pressure compounds; development of a method to predict the vibrational frequencies of two- and three-ring polycyclic molecules to an accuracy sufficient for identifying the fundamental vibrations in experimental spectra; and development of a method to calculate the kinetic energy expansions as a function of the coordinate for the ring-puckering, ring-twisting (in-phase), and ring-twisting (out-of-phase) vibrations of 9,10-dihydroanthracene and related molecules.

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

171

Calorimetric and structural studies of tetrabutylammonium bromide ionic clathrate hydrates.  

PubMed

In the present work, characteristic properties of tetrabutylammonium bromide (TBAB) ionic clathrate hydrates structures were studied by single-crystal X-ray structure analysis. The structures of three different tetragonal TBAB ionic clathrate hydrates that were formed in our experiments were based on the same water lattice of tetragonal structure I (TS-I) differing in the ways of including bromide anions and arranging tetrabutylammonium cations. We demonstrated that (1) Br(-) can be included into the water lattice, replacing two water molecules, (2) the butyl group of the cation can be inserted not only in large T and P cavities but also in small D cavities of the water lattice TS-I, and (3) one of the reasons for polytypism of ionic clathrate hydrates on the basis of TS-I is the occurrence of alternative modes of arrangements of four-compartment cavities in adjacent layers of the water framework. The compositions of three TBAB ionic clathrate hydrates TBAB·38.1H2O, TBAB·32.5H2O, and TBAB·26.4H2O were determined by chemical analysis, and their enthalpies of fusion were measured by differential scanning calorimetry (DSC). From the obtained results, the enthalpies of the TBAB hydrate formation from TBAB and water were calculated thermodynamically. PMID:23947486

Rodionova, Tatyana V; Komarov, Vladislav Yu; Villevald, Galina V; Karpova, Tamara D; Kuratieva, Natalia V; Manakov, Andrey Yu

2013-08-30

172

Calorimetric glass transition explained by hierarchical dynamic facilitation  

PubMed Central

The glass transition refers to the nonequilibrium process by which an equilibrium liquid is transformed to a nonequilibrium disordered solid, or vice versa. Associated response functions, such as heat capacities, are markedly different on cooling than on heating, and the response to melting a glass depends markedly on the cooling protocol by which the glass was formed. This paper shows how this irreversible behavior can be interpreted quantitatively in terms of an East-model picture of localized excitations (or soft spots) in which molecules can move with a specific direction, and from which excitations with the same directionality of motion can appear or disappear in adjacent regions. As a result of these facilitated dynamics, excitations become correlated in a hierarchical fashion. These correlations are manifested in the dynamic heterogeneity of the supercooled liquid phase. Although equilibrium thermodynamics is virtually featureless, a nonequilibrium glass phase emerges when the model is driven out of equilibrium with a finite cooling rate. The correlation length of this emergent phase is large and increases with decreasing cooling rate. A spatially and temporally resolved fictive temperature encodes memory of its preparation. Parameters characterizing the model can be determined from reversible transport data, and with these parameters, predictions of the model agree well with irreversible differential scanning calorimetry.

Keys, Aaron S.; Garrahan, Juan P.; Chandler, David

2013-01-01

173

MEASUREMENT OF THE Fe VIII-Fe XVI 3-3 EMISSION IN THE EXTREME ULTRAVIOLET AND COMPARISON WITH CHIANTI  

SciTech Connect

Laboratory measurements of the n = 3 to n = 3 emission from M-shell iron ions are presented and compared to synthetic spectra from the CHIANTI spectral model. The measurements cover the range 170-290 Angstrom-Sign and are made at an electron density of about 10{sup 11} cm{sup -3}. Emission from Fe VIII through Fe XVI has been identified. Excellent agreement with CHIANTI predictions is found for most lines. Twenty weaker features are noted in the laboratory data that are either absent in CHIANTI or have recently been added and correspond to lines that have not been verified by experimental measurements. A few of these lines may have already been observed (but not yet identified) in the Sun. The features are attributed to emission from various charge states of iron, notably Fe IX and Fe XIII, and two features have been identified as transitions in Fe VIII, i.e., the 3p{sup 6}3d {sup 2}D{sub 5/2}-3p {sup 5}3d{sup 2} {sup 2}P{sub 3/2} and the 3p {sup 6}3d {sup 2}D{sub 3/2}-3p {sup 5}3d{sup 2} {sup 2}P{sub 1/2} transitions at 225.25 {+-} 0.12 and 226.35 {+-} 0.10 Angstrom-Sign , respectively. Seven lines in Fe XI, Fe XII, and Fe XIII between 200 and 205 Angstrom-Sign are noted for which the wavelengths in the CHIANTI database disagree with those in the current database of the National Institute of Standards and Technology. Our measurements of five of these lines appear to agree with the assignments used in CHIANTI.

Beiersdorfer, P.; Lepson, J. K. [Space Sciences Laboratory, University of California, Berkeley, CA 96720 (United States)

2012-08-01

174

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

NASA Astrophysics Data System (ADS)

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 ? 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.

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

2000-10-01

175

Acidity of Hydrocarbons. XVI. Equilibrium Acidities of Hydrocarbon Acids in Cyclohexylamine.  

National Technical Information Service (NTIS)

Equilibrium constants were determined in cyclohexylamine for reactions A(-)M(+) + BH reversibly yields AH + B(-)M(+) in which AH and BH are hydrocarbons whose corresponding carbanions show usable spectral differences and M is lithium or cesium. The soluti...

A. Streitwieser J. I. Brauman J. H. Hammons A. H. Pudjaatmaka

1964-01-01

176

Calorimetric electron telescope mission. Search for dark matter and nearby sources  

NASA Astrophysics Data System (ADS)

We are developing the CALorimetric Electron Telescope, CALET, mission for the Japanese Experiment Module—Exposed Facility, JEM-EF, of the International Space Station, ISS. Major scientific objective is a search for nearby cosmic ray sources and dark matter by carrying out a precise measurement of the electrons in 1 GeV-20 TeV and the gamma-rays in 20 MeV-several TeV. CALET has, moreover, a capability to measure cosmic ray H, He and heavy ions up to 1000 TeV. It will also have a function to monitor the solar activity and the gamma-ray bursts. The phase A study has started on a schedule of the launch in early 2014 by the H-II Transfer Vehicle, HTV, for a 5-year observation.

Torii, Shoji; CALET Collaboration

2011-02-01

177

A solution calorimetric study on stability of superconducting YBa2Cu3O6.91  

NASA Astrophysics Data System (ADS)

The enthalpies of solution of 90K superconducting YBa2Cu3O6.91 in 1N HCl aqueous solution has been measured calorimetrically at 298K. In combination with auxilliary values from literatures, the standard enthalpies of formation of YBa2Cu3O6.91 has been derived. The value of ?fHm°(YBa2Cu3O6.91) is estimated 3027 +/- ? kJ/mol (? is from the auxilliary values and experimental error and is less than 5). By use of entropy value of YBa2Cu3O6.91. we found an increase in the stability of the compound relative to the parent oxides (Y2O3, BaO and CuO) from 300K up to 1156K. These results explain why the superconducting YBC oxide has a tendency to decompose above 1200K in the thermodynamic view point.

Kang, Seong-Gu; Choy, Jin-Ho; Jung, Duk-Young; Won Choi, Q.

1991-12-01

178

Total hemispherical emittance measured at high temperatures by the calorimetric method  

SciTech Connect

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.

DiFilippo, F. [Case Western Reserve Univ., Cleveland, OH (United States); Mirtich, M.J.; Banks, B.A. [Lewis Research Center, Cleveland, OH (United States); Stidham, C.; Kussmaul, M. [Cleveland State Univ., OH (United States)

1994-09-01

179

Calorimetric and dynamic light-scattering investigation of cationic surfactant--DNA complexes.  

PubMed

By means of combined calorimetric and dynamic light-scattering measurements, we have investigated the conformational behavior of DNA chains after thermal melting in the presence of a cationic surfactant at different concentrations, up to a surfactant-to-phosphate group molar ratio close to unity. Both the specific heat capacity, C(ex)(p) and the hydrodynamic radius R of the DNA chains provide support for the existence of two structural arrangements with different thermal stabilities, coexisting in the bulk solution. Although a component remains an elongated unfolded DNA chain originated in the thermal denaturation, the second component, consisting of DNA-surfactant complexes, assumes a compact structure with an average size of about 80 nm, whose thermal denaturation occurs at temperatures higher than 100 degrees C. PMID:17134241

Marchetti, S; Onori, G; Cametti, C

2006-12-01

180

Evidence of Landau tricritical behaviour in TGSe by calorimetric measurements: effect of a weak uniaxial stress  

NASA Astrophysics Data System (ADS)

The paraelectric-ferroelectric phase transition of a single crystal of triglycine selenate TGSe, whose first- or second-order character is controversial, has been studied using a high sensitivity calorimetric technique. The specific heat of a highly pure TGSe has been measured and no evidence of latent heat has been found. The anomalous part of the specific heat shows Landau tricritical behaviour. Experimental data have been fitted to a 2-6 Landau potential, whose coefficients have also been obtained. A weak uniaxial stress applied along the ferroelectric axis (10 bar) decreases the anomalous part of the specific heat. This effect is different for cooling and heating runs. The equilibrium data are those obtained on heating that fit to a 2-4-6 Landau potential, which indicates that the transition shifts to second order with the effect of uniaxial stress.

Romero, F. J.; Gallardo, M. C.; Jiménez, J.; Czarnecka, A.; Koralewski, M.; del Cerro, J.

2004-11-01

181

Simulation work on calorimetric energy resolution for the TAC-PF Detector  

NASA Astrophysics Data System (ADS)

According to the Turkish Accelerator Center (TAC) project, a tau-charm factory is proposed based on colliding a 1 GeV electron beam against a 3.5 GeV positron beam. The Particle Factory (TAC-PF) detector will be constructed for the detection of the producing particles from this collision. PbWO4 and CsI(Tl) crystals are considered for the construction of the electromagnetic calorimeter. The photons generated from incident particles in the crystal material are detected by Avalanche photodiodes (APD) or PIN photodiodes placed at the end of the crystal. In this work, the contribution to the calorimetric energy resolution from both the shower fluctuations in the crystal and photoelectron statistics in the detectors have been simulated for PbWO4-APD and PbWO4-PIN combinations.

Tapan, Ilhan; Kocak, Fatma

2012-12-01

182

Monoclinic to tetragonal transformations in hafnia and zirconia: A combined calorimetric and density functional study  

NASA Astrophysics Data System (ADS)

We use a combination of density functional theory and calorimetric measurements to investigate the monoclinic to tetragonal transition in hafnia and zirconia. We measure the transition enthalpies to be 8.4±0.7kJ/mol in hafnia and, as previously reported, 5.272±0.544kJ/mol in zirconia. Calculated values are 10.21 and 7.50 kJ/mol for hafnia and zirconia, respectively. We formulate a theoretical model of the phase transition consistent with the martnesitic character of the transformations. The transition barriers of 20.3 and 16.3 kJ/mol are estimated for hafnia and zirconia, respectively. We report the phonon spectra of monoclinic and tetragonal phases of both oxides and identify the Raman and IR active modes. The theoretical results compare well with available experiments. We present a comprehensive theoretical comparison of thermodynamic properties of zirconia and hafnia including the temperature dependence of specific heat.

Luo, Xuhui; Zhou, Wei; Ushakov, Sergey V.; Navrotsky, Alexandra; Demkov, Alexander A.

2009-10-01

183

Electrochemical and calorimetric investigations of some thermodynamic properties of EuCl3 and EuCl2 dissolved in alkali chloride melts  

NASA Astrophysics Data System (ADS)

The electroreduction of EuCl3 in alkali chloride melts (NaCl KCl, KCl, CsCl) was studied in the temperature range 973 1123 K by different electrochemical methods. It was determined that electrochemical reduction of Eu(III) in alkali chloride molten salts occurs via two successive reversible stages involving transfer of one and two electrons. The formal standard potentials of EEu(II)/Eu?, EEu(III)/Eu? and formal redox potentials of EEu(III)/Eu(II)? were determined from open-circuit potentiometry and linear sweep voltammetry data. The thermodynamics of formation dilute solutions of europium di-and tri-chloride in alkali chloride melts was determined. The relative partial molar enthalpies of mixing EuCl2 with alkali chloride melts when dilute solutions are formed have been measured previously by direct calorimetry in a Calvet type calorimeter using of ampoule break-off technique. It was shown that the values determined from electrochemical measurements are in a good agreement with those data obtained by calorimetric method.

Kuznetsov, S. A.; Rycerz, L.; Gaune-Escard, M.

2005-09-01

184

Complexation of manganese(II) by cyclohexano-15-crown-5 in propylene carbonate: Calorimetric and X-ray crystallographic investigation  

Microsoft Academic Search

Calorimetric titrimetry reveals that cyclohexano-15-crown-5 (C15C5) forms a 1:1 complex with Mn(II) ions (2.5 mM) in propylene carbonate (PC) solution to which was added levels of water up to 134 mM. The reaction proceeds with a strong driving force (log K = 4.7-5.0) and is enthalpically driven overall, but the magnitude of the enthalpy change decreases with increasing water concentration

Yanpei Deng; John H. Burns; Bruce A. Moyer

1995-01-01

185

The dynamic shear response of the Zr base bulk metallic glass around the calorimetric glass transition temperature  

Microsoft Academic Search

The dynamic shear response of a bulk Zr55Cu25Ni5Al10Nb5 metallic glass has been investigated in the vicinity of calorimetric glass transition temperature, Tg. Similar to other glass formers, the Zr base bulk metallic glass exhibits typical features of the dynamic glass transition. The intermediate fragility index, m, indicates that the Zr base alloy belongs to the category of relatively strong glass

Q. Wang; J. M. Pelletier; H. Xu; L. Xia; X. H. Tan; Y. D. Dong

2005-01-01

186

Calorimetric Electron Telescope (CALET) to observe cosmic-ray electrons and gamma-rays on the International Space Station  

Microsoft Academic Search

We have proposed to make observations of high energy cosmic rays with CALET (CALorimetric Electron Telescope) on the International Space Station. Our main objective is to observe electrons up to 20TeV to investigate origin and propagation of electrons in the Galaxy. Acceleration in nearby supernovae can lead to contributions to the electron spectrum in energies up to tens of TeV.

Tadahisa Tamura; Shoji Torii

2010-01-01

187

Temperature-modulated differential scanning calorimetric measurements on pre-melting behavior of nascent ultrahigh molecular mass polyethylene  

Microsoft Academic Search

Temperature-modulated differential scanning calorimetric (TMDSC) measurements on nascent ultrahigh molecular mass polyethylene (UHMMPE) in scanning as well as quasi-isothermal mode are presented. From these measurements different processes, which contribute to the modulated heat flow in the pre-melting region, both exothermic and endothermic in character, can be separated. One of them only occur on the first heating of the nascent material.

Günther W. H Höhne; Lada Kurelec; Sanjay Rastogi; Piet J Lemstra

2003-01-01

188

Calorimetric Study of the Diastereomeric Interactions of Enantiomeric Iso-octyl-benzoyloxybenzoate Solutes with a Chiral Liquid Crystal  

Microsoft Academic Search

Precision differential scanning calorimetric (DSC) analysis of the effect of doping cholesteryl nonanoate with the enantiomers of 4-(4-n-hexyloxybenzoyloxy)-isooctyl benzoate (R811 and S811) has been performed. Depressions of the enthalpies of both phase transitions, from crystalline to cholesteric and from cholesteric to isotropic phases, were found to be ? 1.5 times greater for the samples of cholesteryl nonanoate doped with left-handed

Y. K. Yarovoy; Vibha Patel; M. M. Labes

1998-01-01

189

Calorimetric measurements of acidity of templated and non-templated HZSM-5 zeolites and their correlation with catalytic activity  

Microsoft Academic Search

HZSM-5 zeolites with and without template having SiO2\\/Al2O3 ratio ?28 have been synthesised. The acidity of the samples was measured by stepwise temperature programmed desorption of ammonia and calorimetric measurement of ammonia adsorption. The difference in catalytic activity of these samples for aniline alkylation and cumene cracking have been discussed from the point of view of total acidity and relative

Sankarasubbier Narayanan; Asima Sultana; Paul Meriaudeau; Claude Naccache; Aline Auroux; Carine Viornery

1996-01-01

190

Anaerobic metabolism in aerobic mammalian cells: information from the ratio of calorimetric heat flux and respirometric oxygen flux.  

PubMed

Calorimetric and respirometric studies of cultured cells show that both neoplastic and non-neoplastic cell types maintain an anaerobic contribution to their total heat flux. In many mammalian cells this can be explained quantitatively by lactate production observed under fully aerobic conditions. Uncoupling and enhanced futile substrate cycling increase the ratio of heat flux to oxygen flux, the calorimetric-respirometric (CR) ratio. The interpretation of calorimetric and respirometric measurements requires an energy balance approach in which experimentally measured CR ratios are compared with thermochemically derived oxycaloric equivalents. The oxycaloric equivalent is the enthalpy change per mole of oxygen consumed, and equals -470 kJ/mol O2 in the aerobic catabolism of glucose, assuming that catabolism is 100% dissipative (the net efficiency of metabolic heat transformation is zero). CR ratios more negative than -470 kJ/mol O2 have been reported in well-oxygenated cell cultures and are discussed in terms of integrated aerobic and anaerobic metabolism. PMID:2184896

Gnaiger, E; Kemp, R B

1990-04-26

191

Determination by the enzyme thermistor of cellobiose formed on degradation of cellulose  

SciTech Connect

A calorimetric assay procedure for the determination of cellobiose was developed. The cellobiose is hydrolyzed by beta-glucosidase and the glucose formed is measured calorimetrically by an enzyme thermistor containing coimmobilized glucose oxidase and catalase. The system was optimized with regard to the arrangement of the enzymes, the pH-dependence of the separated enzymic steps, and of the total system. By placing the Beta-glucosidase in a precolumn that could be switched in and out of the flow through the enzyme thermistor, both cellobiose and glucose present in the sample could be determined. The performance with saturated solutions and crude samples from cellulose degradation experiments was investigated.

Danielsson, B.; Rieke, E.; Mattiasson, B.; Winquist, F.; Mosbach, K.

1981-01-01

192

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

NASA Astrophysics Data System (ADS)

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.

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

1993-07-01

193

Calorimetric observation combined with the detection of particle emissions during the electrolysis of heavy water  

NASA Astrophysics Data System (ADS)

Several calorimetric measurements on electrolysis processes for monitoring the ``cold fusion'' event are represented in this work. A Calvet microcalorimeter with its auxiliaries such as amplifier, recorder, computer etc. was used here for measuring the output power generated during these processes. And at the same time, the total electric input power was recorded for comparing with differences between the out power (or the power measured by the calorimeter) and the electric power minus the equivalent of the D2O (or H2O) formation enthalpy (1.54 (voltage) x I (current)) continuously. After a period of cell operation, over about two weeks, a steady production of ``Excess Heat'' could be demonstrated on the recordings. In particular, there are sporadic power ``excursions'' or ``burst'' monitored in uncertain time. There results could not incontestably show that the cold fusion event has been monitored. Because, at the same time, the neutrons, tritiums, and other particles produced during the processes had not been found out by some types of films being able to detect different kinds of particles yet.

Zhang, Zhong L.; Yan, Bao Z.; Wang, Ming G.; Gu, Jin; Tan, Fu

1991-05-01

194

Calorimetric investigation of the structural relaxation of amorphous materials: evaluating validity of the methodologies.  

PubMed

Although the potential advantages of the amorphous solid state is widely recognized among pharmaceutical researchers, its industrial applications have been mainly limited to freeze-dried injectable formulations where the amorphous form is naturally produced. Applications in oral dosage forms have been limited due, at least in part, to the poor state of knowledge regarding physical properties and stability of amorphous materials. Relaxation behavior is perhaps one of the most important physical characteristics of amorphous materials because relaxation kinetics are closely related to physical and chemical stability. Although recent developments in calorimetry methodology have facilitated detailed characterization of relaxation behavior, some experimental difficulties remain, and quantitative analysis of structural relaxation is still under development. This review focuses on the calorimetric investigation of the structural relaxation of drugs and excipients, and discusses the difficulties in the experimental evaluation of the relaxation time by those methods. We also present an original investigation of the impact of increases in relaxation time during an annealing experiment on the values of relaxation time, tau, and stretched exponential constant, beta, obtained from analysis of the experiment according to the Kohlraush-Williams-Watts kinetic model. Using results from a numerical simulation, we find that the values of tau and beta obtained from the data analysis are too large and too small, respectively, but the value of stretched relaxation time, tau(beta), remains reliable. The time dependence of the relaxation time is likely to play an important role in the non-Arrhenius behavior of pharmaceutical glasses. PMID:15793805

Kawakami, Kohsaku; Pikal, Michael J

2005-05-01

195

Thermal transport across incommensurate phases in potassium selenate: photo-pyroelectric and calorimetric measurements.  

PubMed

The thermal transport properties-thermal diffusivity, thermal conductivity and specific heat capacity-of potassium selenate crystal have been measured through the successive phase transitions, following the photo-pyroelectric thermal wave technique. The variation of thermal conductivity with temperature through the incommensurate (IC) phase of this crystal is measured. The enhancement in thermal conductivity in the IC phase is explained in terms of heat conduction by phase modes, and the maxima in thermal conductivity during transitions is due to enhancement in the phonon mean free path and the corresponding reduction in phonon scattering. The anisotropy in thermal conductivity and its variation with temperature are reported. The variation of the specific heat with temperature through the high temperature structural transition at 745 K is measured, following the differential scanning calorimetric method. By combining the results of photo-pyroelectric thermal wave methods and differential scanning calorimetry, the variation of the specific heat capacity with temperature through all the four phases of K(2)SeO(4) is reported. The results are discussed in terms of phonon mode softening during transitions and phonon scattering by phase modes in the IC phase. PMID:21715826

Philip, J; Manjusha, M V

2008-12-15

196

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

SciTech Connect

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.

Miroshnikova, Y. A.; Elsenbeck, M.; Zastavker, Y. V. [Franklin W. Olin College of Engineering, Needham, MA (United States); Kashuri, K; Iannacchione, G. S. [Worcester Polytechnic Institute, Worcester, MA (United States)

2009-04-19

197

A ternary feldspar-mixing model based on calorimetric data: development and application  

NASA Astrophysics Data System (ADS)

A mixing model for high structural state ternary feldspars in the NaAlSi3O8-KAlSi3O8-CaAl2Si2O8 system is presented based exclusively on calorimetric and volumetric measurements. Comparisons with existing mixing models, which are based on phase-equilibrium experiments, reveal distinct differences. The incorporation of K into Ca-rich plagioclase and of Ca into K-rich alkali feldspar is more strongly limited by our calorimetry-based model, whereas the stability field of Na-rich feldspars is broadened. Natural feldspar assemblages from well-studied magmatic and high-grade metamorphic rocks (i.e. a teschenite sill in Scotland, the Klokken syenogabbro in Greenland, and a granulite-facies metapelite in Sri Lanka) were used to test the mixing models. It was found that the new model largely eliminates discrepancies between observed and predicted feldspar compositions that were present in earlier attempts. The reasons for the problems associated with phase-equilibrium based mixing models are discussed.

Benisek, Artur; Dachs, Edgar; Kroll, Herbert

2010-09-01

198

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

SciTech Connect

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.

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

1981-11-01

199

Europium(III) tetrakis(?-diketonate) complex as an ionic liquid: a calorimetric and spectroscopic study.  

PubMed

An intrinsic photoluminescent ionic liquid based on europium(III) tetrakis(?-diketonate) complex with a tetraalkylphosphonium as counterion was synthesized. Calorimetric measurements showed a melting point at 63 °C, which allows the ionic liquid classification. When cooling the material from the liquid state, metastable supercooled ionic liquid is obtained, as seen from NMR spectroscopy as well. Eu(III) photoluminescence is clearly observed while the absorption spectra of the ligand is dominant, showing the antenna effect. This was confirmed with submicrosecond time scale luminescence spectroscopy, where a rise of Eu(III) emission is observed with the correspondent decay of the ligand excited state. Temperature effects in the photoluminescence are also shown, being prominent above the melting point where the intensity decreases with Arrhenius behavior. Eu(III) luminescence decays also show features characteristic of energy migration between homologue Eu(III) species. Solvent effects were also studied by NMR and Luminescence spectroscopies, highlighting that the nucleophilicity of organic solvents such as n-alcohols leads to a coordination with Eu(III), which ultimately compromises the stability of the complex. PMID:23477603

Pereira, Cláudia C L; Dias, Sofia; Coutinho, Isabel; Leal, J P; Branco, Luís C; Laia, César A T

2013-03-11

200

An IR and Calorimetric Investigation of the Structural, Crystal-Chemical and Thermodynamic Properties of Hydrogrossular  

NASA Astrophysics Data System (ADS)

The garnet class of phases is extremely broad in terms of composition and structural properties. Garnet is found in nature and various synthetic garnet phases have a number of important technical applications. There exist the rock-forming silicate garnets that are so widespread geologically. An additional class is given by the so-called "hydrogarnets" in which the tetrahedral site (Wyckoff position 24d) is empty. At relatively low temperatures there is complete solid solution between Ca3Al2Si3O12 and Ca3Al2H12O12, for example. The substitution mechanism can be written as O4H4 \\lrarr SiO4. The latter, pure OH-containing end-member, which has not been found in nature, is termed katoite/hydrogrossular. Its structure has been investigated by various workers by X-ray and neutron diffraction and by proton NMR, IR and Raman spectroscopic methods. At ambient conditions the structure has the "standard" garnet cubic symmetry of Ia-3d. At high pressures, and possibly at low temperatures, a different structure may occur. We measured the low temperature IR spectra and heat capacity of katoite in order to understand its structural, crystal-chemical and thermophysical properties. A sample of Ca3Al2H12O12 was synthesized hydrothermally in Au capsules at 250 °C and 3 kb water pressure. X-ray powder measurements show that about 98-99% katoite was obtained. Powder IR spectra were recorded between 298 K and 10 K. The measured spectra are considerably different in the high wavenumber region, where O-H stretching modes occur, between 298 K and 10 K. At room temperature the IR-active O-H band located around 3662 cm-1 is broad and it narrows and shifts to higher wavenumbers and also develops structure below about 80 K. Concomitantly, additional weak intensity O-H bands located around 3600 cm-1 begin to appear and they become sharper and increase in intensity with further decreases in temperature down to 10 K. The spectra indicate that the vibrational behavior of individual OH groups and their collective interactions measurably affect the lattice dynamic (i.e. thermodynamic) behavior. The low temperature heat capacity behavior was investigated with a commercially designed relaxation calorimeter between 5 and 300 K on a mg-sized sample. The heat capacity data are well behaved at T < 300 K and show a monotonic decrease in magnitude with decreasing temperature. A standard third-law entropy value of So = 421.7 ± 1.6 J/mol·K was calculated. Using this new calorimetric-based So value and published standard enthalpy of formation data for katoite, a calorimetric-based Gibbs free energy of formation at 298 K can be obtained as ?G°f = -5021.2 kJ/mol. The Cp data show no evidence for any phase transition as possibly expected by the change in OH-mode behavior with decreasing temperature. We have no explanation for the appearance of the additional modes. It is worth noting that the katoite crystal structure in terms of lattice dynamic or thermodynamic behavior should be thought of having OH groups and not O4H4 clusters or polyhedral units as is often written in the literature. The single crystallographic OH group in katoite shows very weak, if any, hydrogen bonding and the H atoms have large amplitudes of vibration. The weak H bonding controls the nature of low energy OH-related vibrations and this leads to its large So value.

Geiger, C. A.; Dachs, E.

2012-04-01

201

High-resolution differential scanning calorimetric analysis of the subunits of Escherichia coli aspartate transcarbamoylase.  

PubMed

The thermal denaturation of the catalytic (c3) and regulatory (r2) subunits of Escherichia coli aspartate transcarbamoylase (c6r6) in the absence and presence of various ligands has been studied by means of highly sensitive differential scanning calorimetry. The denaturation of both types of subunit is irreversible as judged by the facts that the proteins coagulate when heated and that no endotherm is observed when previously scanned protein is rescanned. Despite this apparent irreversibility, there is empirical justification for analyzing the calorimetric data in terms of equilibrium thermodynamics as embodied in the van't Hoff equation. The observed curves of excess apparent specific heat vs. temperature are asymmetric and can be expressed within experimental uncertainty as the sums of sequential two-state steps, a minimum of two steps being required for r2 and three for c3. As previously reported [Vickers, K. P., Donovan, J. W., & Schachman, H. K. (1978) J. Biol. Chem. 253, 8493-8498], the addition of the effectors ATP and CTP raises the denaturation temperature of r2 and lowers that of c3 while the addition of the bisubstrate analogue N-(phosphonoacetyl)-L-aspartate raises the denaturation temperature of c3 and lowers that of r2. These effects vary with ligand concentration in the manner expected from the van't Hoff equation, indicating that they are simply manifestations of Le Chatelier's principle rather than being due to "stabilization" or "destabilization" of the proteins. The denaturational enthalpy is increased in those cases of ligand binding in which the denaturation temperature is increased, because of the contribution from the enthalpy of dissociation of the ligand. PMID:3910085

Edge, V; Allewell, N M; Sturtevant, J M

1985-10-01

202

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

PubMed Central

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.

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

1994-01-01

203

Calorimetric study of blend miscibility of polymers confined in ultra-thin films  

NASA Astrophysics Data System (ADS)

Miscibility in blends of polystyrene and poly(phenylene oxide) (PS/PPO) confined in thin films (down to 6 nm) was investigated using a recently developed sensitive differential alternating current (AC) chip calorimeter. Comparison of composition dependence of glass transition in thin films with common models should provide information on miscibility. This study focuses on the blend system polystyrene and poly(phenylene oxide) (PS/PPO) because it is thought as a miscible model system in the whole composition range. Furthermore, its local dynamic heterogeneity is already identified by dynamic mechanic thermal analysis (DMTA) and solid state NMR techniques. For this blend, we find that even for the thinnest films (6 nm, corresponding to about half of PPO's radius of gyration Rg) only one glass transition is observed. The composition dependence of Tg is well described by the Fox, Couchman or Gordon-Taylor mixing law that are used for the miscible bulk blends. Although there is a contradicting result on whether Tg decreases with decreasing film thickness between our calorimetric measurements and Kim's elipsometric measurements on the same blend (Kim et al. Macromolecules 2002, 35, 311-313), the conclusion that the good miscibility between PS and PPO remains in ultrathin films holds for both studies. Finally, we show that our chip calorimeter is also sensitive enough to study the inter-layer diffusion in ultrathin films. PS chain in a thin PS/PPO double layer that is prepared by spin coating PPO and PS thin film in tandem will gradually diffuse into the PPO layer when heated above Tg of PS, forming a PSxPPO100-x blend. However, above the PSxPPO100-x blend, there exists an intractable pure PS like layer (˜30 nm in our case) that does not diffuse into the blend beneath even staying at its liquid state over 10 hours.

Jiang, W.; Du, M.; Gu, Q.; Jiang, J.; Huth, H.; Zhou, D.; Xue, G.; Schick, C.

2010-10-01

204

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

SciTech Connect

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.

Kabadi, V.N.

1992-10-01

205

Numerical analysis of the AC loss in a high-TC superconducting cable measured by calorimetric method  

NASA Astrophysics Data System (ADS)

We calculated the AC property in a high-TC superconducting (HTS) cable fabricated by Furukawa Electric Industries Ltd (FEI) by using an electric-circuit (EC) model. The AC loss of the HTS cable is measured by a calorimetric method by FEI. The measured AC loss and the calculated one are almost equal. According to the calculated results, the layer’s currents are uniform on the low transport current. On the high transport current, the layer’s current distribution indicates a drift-current phenomenon.

Noji, H.; Ikeda, K.; Uto, K.; Hamada, T.

2005-09-01

206

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

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

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

2006-10-01

207

Differential-scanning-calorimetric study of the irreversible thermal denaturation of 8 kDa cytotoxin from the sea anemone Radianthus macrodactylus.  

PubMed Central

A differential-scanning-calorimetric study of the thermal denaturation of a sea-anemone (Radianthus macrodactylus) 8 kDa cytolytic toxin was carried out. The calorimetric traces were found to be irreversible and scan-rate-dependent under the experimental conditions employed. Scan-rate-dependent thermograms were explained in terms of a two-state kinetic model N k -->D, where k is a first-order kinetic constant that changes with temperature as given by the Arrhenius equation, N is the native state of the toxin, and D the denatured one.

Zhadan, G G; Shnyrov, V L

1994-01-01

208

Study of the dichromate-catalysed hydrogen peroxide decomposition: Comparison of different batch mode reactors for the kinetics determination  

Microsoft Academic Search

This paper deals with an experimental batch mode study of a chemical homogeneous reaction: the dichromate-catalysed hydrogen peroxide decomposition. The thermodynamic properties and the kinetic parameters of the reaction are simultaneously determined using a calorimetric approach. Various batch-operating modes (adiabatic, isoperibolic, or differential thermal analysis) are compared and it is shown that the determined parameters do not depend on the

Nader Frikha; Eric Schaer; Jean-Léon Houzelot

2005-01-01

209

Urea-induced dissociation and unfolding of dodecameric glutamine synthetase from Escherichia coli: calorimetric and spectral studies.  

PubMed Central

Urea-induced dissociation and unfolding of manganese.glutamine synthetase (Mn.GS) have been studied at 37 degrees C (pH 7) by spectroscopic and calorimetric methods. In 0 to approximately 2 M urea, Mn.GS retains its dodecameric structure and full catalytic activity. Mn.GS is dissociated into subunits in 6 M urea, as evidenced by a 12-fold decrease in 90 degrees light scattering and a monomer molecular weight of 51,800 in sedimentation equilibrium studies. The light scattering decrease in 4 M urea parallels the time course of Trp exposure but occurs more rapidly than changes in secondary structure and Tyr exposure. Early and late kinetic steps appear to involve predominantly disruption of intra-ring and inter-ring subunit contacts, respectively, in the layered hexagonal structure of Mn.GS. The enthalpies for transferring Mn.GS into urea solutions have been measured by titration calorimetry. After correcting for the enthalpy of binding urea to the protein, the enthalpy of dissociation and unfolding of Mn.GS is 14 +/- 4 cal/g. A net proton uptake of approximately 50 H+/dodecamer accompanies unfolding reactions. The calorimetric data are consistent with urea binding to multiple, independent sites in Mn.GS and the number of binding sites increasing approximately 9-fold during the protein unfolding.

Zolkiewski, M.; Nosworthy, N. J.; Ginsburg, A.

1995-01-01

210

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

NASA Astrophysics Data System (ADS)

The measurement of calorimetric spectra following atomic weak decays, beta ( ?) 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 ?s 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 ?-decay of 187Re and the EC of 163Ho. We show results obtained with detectors optimized for 187Re and for 163Ho 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 163Ho ions already shows excellent results. An energy resolution of 12 eV FWHM and a rise time of 90 ns were measured.

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

2012-06-01

211

A differential scanning calorimetry method to determine the isothermal crystallization kinetics of cocoa butter  

Microsoft Academic Search

This research aimed to reduce the variability on the data obtained from differential scanning calorimetric (DSC) analysis of the isothermal crystallization kinetics of cocoa butter.To enable transformation of the DSC crystallization peak to a sigmoid crystallization curve, the DSC peak area has to be integrated. Usually, the start and end points of the crystallization peak are determined visually. The result

Imogen Foubert; Peter A. Vanrolleghem; Koen Dewettinck

2003-01-01

212

Calorimetric Measurements of Energy Release in Nb-Ti-50 Superconducting Alloy in Irradiation by 8.5 GeV Protons.  

National Technical Information Service (NTIS)

The calorimetric method of measurements of energy release in the Nb-Ti-50 alloy caused by irradiation by 8.5 GeV proton beam is described. The results of measurements at helium temperatures for sample 2 mm thick are given. The obtained value of energy rel...

I. N. Goncharov V. M. Drobin N. M. Osipova S. I. Yakovlev L. N. Zaitsev

1979-01-01

213

Dielectric, calorimetric and elastic anomalies associated with the first order I4/mcm \\leftrightarrow Pbcm phase transition in (Ca, Sr)TiO3 perovskites  

NASA Astrophysics Data System (ADS)

Conduction calorimetry has been used to determine with high precision the latent heat and variation in heat capacity which accompany the first order I4/mcm \\leftrightarrow Pbcm phase transition in perovskites with compositions (Ca1-xSrx)TiO3, x = 0.65, 0.68, 0.74 (CST65, CST68, CST74). In CST65 (CST68), the latent heat is dissipated/absorbed over a temperature interval of ~11 K (~6 K), which is centred on ~292 K (~258 K) during cooling and ~302 K (~270 K) during heating. The magnitude of the latent heat diminishes with increasing SrTiO3 content and was not detected in CST74. Integration of the latent heat and excess heat capacity yields small excess entropies, which are consistent with the structural changes being displacive rather than order-disorder in origin. Resonant ultrasound spectroscopy measurements on the same CST65 sample as used for dielectric and calorimetric measurements through the same temperature intervals have allowed quantitative correlations to be made with the bulk modulus, shear modulus and acoustic dissipation parameter, Q-1. The dielectric anomaly and changes in Q-1 can be understood as being linear combinations of the properties of the separate I4/mcm and Pbcm phases in proportion to their volume fractions across the two-phase field. A change of only ~0.5-1 GPa has been detected in the bulk modulus but the shear modulus softens by ~5-8 GPa as the transition interval is approached from above and below. This shear mode softening presumably reflects clustering and/or phonon softening in both the I4/mcm and Pbcm structures. This pattern of structure-property relations could be typical of first order transitions in perovskites where there is no group/subgroup relationship between the high and low symmetry phases.

Manchado, J.; Romero, F. J.; Gallardo, M. C.; del Cerro, J.; Darling, T. W.; Taylor, P. A.; Buckley, A.; Carpenter, M. A.

2009-07-01

214

CALORIMETRIC DETERMINATION OF ABSORBED DOSE AND GFe +++ OF THE FRICKE DOSIMETER WITH 10Mev AND 20Mev ELECTRONS  

Microsoft Academic Search

The construction and operation details of a local absorbed dose ; microcalorimeter are presented. This calorimeter measures the absorbed dose rate ; at any desired point within an irradiated medium. The measurement is specific to ; a sufficiently limited region (2.0 cm in dia, 0.3 cm deep) that the measurement ; is essentially at a point and no integration or

J. Geisselsoder; K. Koepke; J. S. Laughlin

1963-01-01

215

A calorimetric approach to the study of the interactions of cytidine-3'-phosphate with bovine seminal ribonuclease.  

PubMed

A calorimetric study at 25 degrees C is reported on the interaction between allosteric bovine seminal ribonuclease and cytidine-3'-phosphate. The results are compared with those obtained under identical experimental conditions for the interaction of pancreatic ribonuclease A and the same nucleotide. The analysis of the data provides evidence that the binding sites of seminal ribonuclease for cytidine-3'-phosphate are not equivalent, in agreement with previous equilibrium dialysis studies. A model with two sites with different affinities toward the nucleotide, the site with higher affinity resembling the binding site of pancreatic ribonuclease, is proposed. The values calculated for the thermodynamic parameters provide an insight of the forces involved in the interaction of the two enzymes with the nucleotide. PMID:2752098

Ambrosino, R; Barone, G; Castronuovo, G; Cultrera, O; Di Donato, A; Elia, V

1989-08-01

216

Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Thermal Properties of Organic Hydrocarbons  

ERIC Educational Resources Information Center

|In first-year general chemistry undergraduate courses, thermodynamics and thermal properties such as melting points and changes in enthalpy ([Delta]H) and entropy ([Delta]S) of phase changes are frequently discussed. Typically, classical calorimetric methods of analysis are used to determine [Delta]H of reactions. Differential scanning…

D'Amelia, Ronald; Franks, Thomas; Nirode, William F.

2007-01-01

217

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)

Certain distributions of relaxation times can be described in terms of a non-exponential response parameter, ?, of value between 0 and 1. Both ? and the relaxation time, ?0, of a material depend upon the probe used for studying its dynamics and the value of ? is qualitatively related to the non-Arrhenius variation of viscosity and ?0. A solute adds to the diversity of an intermolecular environment and is therefore expected to reduce ?, i.e., to increase the distribution and to change ?0. We argue that the calorimetric value ?cal 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 ? determined from other properties, and report a study of ?cal of two sets of binary mixtures, each containing a different molecule of ~2 nm size. We find that ?cal changes monotonically with the composition, i.e., solute molecules modify the nano-scale composition and may increase or decrease ?0, but do not always decrease ?cal. (Plots of ?cal against the composition do not show a minimum.) We also analyze the data from the literature, and find that (i) ?cal of an orientationally disordered crystal is less than that of its liquid, (ii) ?cal varies with the isomer's nature, and chiral centers in a molecule decrease ?cal, and (iii) ?cal decreases when a sample's thickness is decreased to the nm-scale. After examining the difference between ?cal and ? determined from other properties we discuss the consequences of our findings for theories of non-exponential response, and suggest that studies of ?cal may be more revealing of structure-freezing than studies of the non-Arrhenius behavior. On the basis of previous reports that ? --> 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 ? < 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.

Johari, G. P.; Khouri, J.

2013-03-01

218

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

PubMed

Certain distributions of relaxation times can be described in terms of a non-exponential response parameter, ?, of value between 0 and 1. Both ? and the relaxation time, ?0, of a material depend upon the probe used for studying its dynamics and the value of ? is qualitatively related to the non-Arrhenius variation of viscosity and ?0. A solute adds to the diversity of an intermolecular environment and is therefore expected to reduce ?, i.e., to increase the distribution and to change ?0. We argue that the calorimetric value ?(cal) 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 ? determined from other properties, and report a study of ?(cal) of two sets of binary mixtures, each containing a different molecule of ?2 nm size. We find that ?(cal) changes monotonically with the composition, i.e., solute molecules modify the nano-scale composition and may increase or decrease ?0, but do not always decrease ?(cal). (Plots of ?(cal) against the composition do not show a minimum.) We also analyze the data from the literature, and find that (i) ?(cal) of an orientationally disordered crystal is less than that of its liquid, (ii) ?(cal) varies with the isomer's nature, and chiral centers in a molecule decrease ?(cal), and (iii) ?(cal) decreases when a sample's thickness is decreased to the nm-scale. After examining the difference between ?(cal) and ? determined from other properties we discuss the consequences of our findings for theories of non-exponential response, and suggest that studies of ?(cal) may be more revealing of structure-freezing than studies of the non-Arrhenius behavior. On the basis of previous reports that ? ? 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 ? < 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 ? T(g), and in the glassy state. PMID:23556762

Johari, G P; Khouri, J

2013-03-28

219

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

SciTech Connect

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.

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

2004-12-01

220

Thermodynamic investigation of a solid–solid phase change material: 2Amino2-methyl-1,3-propanediol by calorimetric methods  

Microsoft Academic Search

An important solid–solid phase change heat storage material (PCM) 2-amino-2-methyl-1,3-propanediol was investigated by calorimetric methods. The molar heat capacities of the compound were measured in the temperature range from 78 to 405K by means of a small sample automated adiabatic calorimeter. A solid–solid and solid–liquid phase transitions were found at T=351.598K and 380.633K, respectively, from the experimental Cp–T curve. The

Tong Bo; Tan Zhi-Cheng; Liu Rui-Bin; Meng Chang-Gong; Zhang Jing-Nan

2010-01-01

221

Effect of Core Width, Placement, and Condition on Calorimetrically Measured AC Loss and Interstrand Contact Resistance of Stainless-Steel-Cored Rutherford Cables  

Microsoft Academic Search

Calorimetric measurements of AC loss were made on Nb3Sn Rutherford cables furnished with cores of widths 4.5, 5.2, and 10.8 mm in the face-on (FO) and edge-on (EO) orientations of the applied AC field. The resulting FO-measured effective interstrand contact resistances, Rperp,e,f,f., were compared with that of the uncored cable after which it was noted that although the uncored Rperp,e,f,f.

E. W. Collings; M. D. Sumption; E. Barzi; D. Turrioni; R. Yamada; A. V. Zlobin; Y. Ilyin; A. Nijhuis

2008-01-01

222

Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Heat Capacity of Metals and Demonstration of Law of Dulong and Petit  

ERIC Educational Resources Information Center

|Today's general chemistry students are introduced to many of the principles and concepts of thermodynamics. In first-year general chemistry undergraduate courses, thermodynamic properties such as heat capacity are frequently discussed. Classical calorimetric methods of analysis and thermal equilibrium experiments are used to determine heat…

D'Amelia, Ronald P.; Stracuzzi, Vincent; Nirode, William F.

2008-01-01

223

The Determination of Photon Flux for Energies between 150 and 300 Mev  

Microsoft Academic Search

A calorimetric method of determining photon flux is described. Absolute calibration was performed with an improved Pb block calorimeter using thermistors as temperature-sensitive elements. Five-minute irradiations were employed with a maximum of 33 milliwatts emerging from a 0.5-in. collimator placed at 115 cm from the betatron target. A secondary standard was developed for the purpose of determining bremsstrahlung flux. This

P. D. Edwards; D. W. Kerst

1953-01-01

224

The phase equilibrium between sillimanite and andalusite as determined from lattice vibrations  

Microsoft Academic Search

The thermodynamic equilibrium between sillimanite and andalusite has been determined from the measured phonon spectra. The corresponding aluminium silicate triple point is found to be in the range T=420° C-440° C and P=3.0–3.2 kbars. From the comparison of calorimetrically determined specific heat functions with those calculated from lattice vibrations additional effects of lattice faults of sillimanite are found to increase

E. Salje; Chr. Werneke

1982-01-01

225

Predicting shear viscosity during volcanic processes at the glass transition: a calorimetric calibration  

Microsoft Academic Search

The viscosity of volcanic melts at the glass transition has been determined for 11 compositions ranging from basanite to rhyolite. Determination of the temperature dependence of viscosity, together with the cooling rate dependence of the glass transition, permits the calibration of the value of the viscosity at the glass transition at a given cooling rate for each melt. Temperature-dependent viscosities

Joachim Gottsmann; Daniele Giordano; Donald B. Dingwell

2002-01-01

226

Calorimetric study of the superconducting and normal state properties of Ca(Fe1-xCox)2As2  

NASA Astrophysics Data System (ADS)

We present a calorimetric study on single crystals of Ca(Fe1-xCox)2As2 (x = 0, 0.032, 0.051, 0.056, 0.063, and 0.146). The combined first order spin-density wave/structural transition occurs in the parent CaFe2As2 compound at 168 K and gradually shifts to lower temperature for low doping levels (x = 0.032 and x = 0.051). It is completely suppressed upon higher doping x >= 0.056. Simultaneously, superconductivity appears at lower temperature with a transition temperature around Tc ~ 14.1 K for Ca(Fe0.937Co0.063)2As2. The phase diagram of Ca(Fe0.937Co0.063)2As2 has been derived and the upper critical field is found to be ?0H(c)2 = 11.5 T and ?0H(ab)c2 = 19.4 T for the c and ab directions, respectively.

Abdel-Hafiez, M.; Harnagea, L.; Singh, S.; Stockert, U.; Wurmehl, S.; Leps, N.; Klingeler, R.; Wolter, A. U. B.; Büchner, B.

2012-12-01

227

Observation and modelling of main-sequence star chromospheres - XVI. Rotation of dK5 stars  

NASA Astrophysics Data System (ADS)

Using two different spectrographs, High Accuracy Radial velocity Planet Search (HARPS) (European Southern Observatory) and SOPHIE (Observatoire de Haute Provence), we have measured v sin i for a sample of dK5 stars. These are the first measurements of v sin i for most of the stars studied here. We measured v sin i to an accuracy of 0.3 km s-1 and a detection limit of about 0.5-1 km s-1. All our targets have similar (R - I)c colour. This is an advantage and facilitates the determination of the narrowest line profiles for v sin i ˜ 0. In our total sample, we detected rotation for 22 stars (three dK5e and 19 dK5 stars), and we did not detect rotation in a further 22 stars. This result shows that there are many dK5 slow rotators, and many more than for dM1 stars. We also report on a newly discovered dK5e star, McC 522, which is also the fastest rotator in our sample. We determine radii and effective temperatures for all our target stars. The effective temperatures were derived using the (R - I)c colour and empirical far-red colour-effective temperature correlations, and the radii were derived from the standard formulae relating Mbol, bolometric correction and Teff. We find that the distribution of P/sin i (the projected rotation period) is rather homogeneous, i.e. the distribution of the 22 detected stars as a function of P/sin i is approximately flat and does not show any maximum, unlike for dM1 stars, a close spectral type. We find that the distribution in v sin i is bimodal, as in dM1 stars, with fast dK5e rotators and slower dK5 rotators. Based on observations available at Observatoire de Haute Provence and the European Southern Observatory data bases and on Hipparcos parallax measurements.

Houdebine, E. R.

2011-09-01

228

Analysis and localization of losses in an induction machine using a calorimetric method  

SciTech Connect

In this paper the authors determine the loss distribution in a 11 kW, fan-cooled, slip-ring, induction machine. They use a simple thermal model which splits the machine into elementary blocks. The parameters of this model are determined by temperature measurements yielded during typical tests. The authors then use the model to analyze and localize the losses under several operating conditions.

Chillet, C.; Isnard, R.; Hadi, A.W.; Brunello, M. (Lab. d'Electrotechnique de Grenoble, URA CNRS 355, BP 46, 38402 St. Martin D'Heres Cedex (FR))

1990-01-01

229

Simulation of solid thermal explosion and liquid thermal explosion of dicumyl peroxide using calorimetric technique  

Microsoft Academic Search

Dicumyl peroxide (DCPO), is produced by cumene hydroperoxide (CHP) process, is utilized as an initiator for polymerization, a prevailing source of free radicals, a hardener, and a linking agent. DCPO has caused several thermal explosion and runaway reaction accidents in reaction and storage zone in Taiwan because of its unstable reactive property. Differential scanning calorimetry (DSC) was used to determine

Sun-Ju Shen; Sheng-Hung Wu; Jen-Hao Chi; Chen-Chung Lin; Jao-Jia Horng; Chi-Min Shu

2011-01-01

230

Crystallization of Polymers Studied by Temperature Modulated Calorimetric Measurements at Different Frequencies  

Microsoft Academic Search

Quasi-isothermal temperature modulated DSC (TMDSC) were performed during crystallization to determine heat capacity as function of time and frequency. Non-reversible and reversible phenomena in the crystallization region of polymers were distinguished. TMDSC yields new information about the dynamics of local processes at the surface of polymer crystals, like reversible melting. The fraction of material involved in reversible melting, which is

C. Schick; M. Merzlyakov; A. Minakov; A. Wurm

2000-01-01

231

A standard calorimetric apparatus for calibrating chemical detectors in systems containing second-generation electron accelerators  

Microsoft Academic Search

The primary sensor is a differential local absorbed-dose calorimeter, which is a form of integral heat-flux one. The flux it measures is independent of the heat source distribution in the absorber and is determined only by the heat production rate there [4]. The absorbed energy D may have various distributions over the depth r in the graphite phantom for various

V. V. Aleikin; V. V. Generalova; A. A. Gromov; Mo N. Gurskii

1988-01-01

232

Thermal and calorimetric investigations on crystalline hydrates of barium hydroxide and their deuterated analogues  

Microsoft Academic Search

The thermal decompositions of Ba(OH)2 · 8H2O, Ba(OH)2 · 8D2O, Ba(OH)2 · H2O and Ba(OH)2 · D2O were studied and the phase transitions were identified by DSC and DTA methods. The corresponding enthalpy changes were determined and compared with those calculated from the thermodynamic data. A decrease of the thermal stability was demonstrated for the deuterated crystal hydrates in comparison

M. Maneva-Petrova; D. Nikolova

1986-01-01

233

Calorimetric studies of interactions between simple peptides and electrolytes in water at 298.15 K  

Microsoft Academic Search

The standard molar enthalpies of solution at infinite dilution ?solHm? of glyclyglycine, glycylglycylglycine and DL-alanyl-DL-alanine in aqueous solutions of sodium chloride and sodium iodide have been determined by calorimetry at the temperature 298.15 K. The results obtained were used to calculate the heterotactic enthalpic interaction coefficients hxy of peptide with the salts in water. The effect of the ion type

Bo?enna Nowicka; Henryk Piekarski

2002-01-01

234

Synthesis of crystalline americium hydroxide, Am(OH)(sub 3), and determination of its enthalpy of formation; estimation of the solubility-product constants of actinide(III) hydroxides.  

National Technical Information Service (NTIS)

This paper reports a new synthesis of pure, microcrystalline Am(OH)(sub 3), its characterization by x-ray powder diffraction and infrared spectroscopy, and the calorimetric determination of its enthalpy of solution in dilute hydrochloric acid. From the en...

L. R. Morss C. W. Williams

1993-01-01

235

Innovation Abstracts, Volume XVI, 1994.  

ERIC Educational Resources Information Center

|This volume of 30 one- to two-page abstracts highlights a variety of innovative approaches to teaching and learning in the community college. Topics covered in the abstracts include: (1) music in the biology classroom; (2) pairing English as a second language and freshman composition students in writing activities; (3) moot court exercises in…

Roueche, Suanne D., Ed.

1994-01-01

236

PREFACE: Sensors & their Applications XVI  

NASA Astrophysics Data System (ADS)

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

Kyriacou, Panicos; O'Riordan, Alan

2011-08-01

237

ALLELOPATHIC PLANTS. XVI. ARTEMISIA SPECIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

The allelopathic effects of Artemisia annua, A. californica, A. princeps var. orientalis, A. tridentata, and A. vulgaris are reviewed. Naturally produced allelopathic compounds that reach target species via natural methods of dissemination (air, soil, and rain) are emphasized. Possible modes of ac...

238

Water sorption/desorption--near IR and calorimetric study of crystalline and amorphous raffinose.  

PubMed

Mass loss at elevated RH is an established method for determining the occurrence of crystallisation of an amorphous material. Through the combination of near infrared spectroscopy and gravimetric vapour sorption, it has been possible to show the transition of raffinose from its spray-dried amorphous form to a crystalline form without this characteristic mass loss. It has also been possible to observe changes in the crystalline material for a period of 30 h subsequent to exposure to elevated relative humidity by near infrared spectroscopy that are not associated with changes in mass, but are related to repacking of hydrate molecules. Drying of the crystalline pentahydrate in the DVS-NIR was seen to show changes in the NIR peak related to -OH. From this, NIR peaks were tentatively ascribed as relating to a penta-, tetra-, tri- and a di-hydrate form, but the sample returned to the amorphous response by the time the water content fell to the equivalent of the monohydrate, indicating that crystallinity had been lost. These observations would be compatible with the hypothesis that lower hydrates of raffinose exist. Due to the absence of mass loss in association with crystallisation, it was found that the enthalpy of crystallisation of amorphous raffinose, as determined by isothermal microcalorimetry, is similar to the enthalpy of fusion determined by differential scanning calorimetry. Finally, it was observed that the early part of the response in the isothermal microcalorimeter was related to mobility of molecules when Tg was above T. This mobility was able to give the bulk morphology of a crystal before the sample developed long range order and crystalline properties. PMID:11564541

Hogan, S E; Buckton, G

2001-10-01

239

Phase transitions in bis-triphenyllead (or tin) diacetylenes. Raman and calorimetric study  

NASA Astrophysics Data System (ADS)

Crystals formed by (C 6H 5) 3-X-C ? C-C ? C-X-(C 6H 5) 3, where X is Pb or Sn, and an equimolecular amount of CH 2Cl 2 or CHCl 3 molecules, have been studied. Phase transition temperatures and enthalpies have been determined by DSC. Raman scattering spectra have been recorded: they show that all four compounds belong to the same space group Pa3 in their high- T phases: they suggest that the low- T space group is P2 12 12 1, implying that the diacetylene interchange group is D 2 at all temperatures.

Bertault, M.; Schott, M.; Peretti, P.; Ranson, P.

1984-02-01

240

Thermochemistry of 2- and 3-thiopheneacetic acids: calorimetric and computational study.  

PubMed

The enthalpies of formation in the condensed and gas states, Delta f H m degrees (cd) and Delta f H m degrees (g), of 2- and 3-thiopheneacetic acids were derived from their respective enthalpies of combustion in oxygen, measured by a rotating bomb calorimeter, and the variation of vapor pressure with temperature determined by the Knudsen effusion technique. Theoretical calculations at the G3 level were performed, and a study on molecular and electronic structure of the compounds has been carried out. Calculated Delta f H m degrees (g) values using atomization and isodesmic reactions are compared with the experimental data. Experimental and theoretical results show that the 3-thiopheneacetic acid is thermodynamically more stable than the 2-isomer. PMID:18816026

Temprado, Manuel; Roux, María Victoria; Jiménez, Pilar; Foces-Foces, Concepción; Notario, Rafael

2008-09-25

241

Isolation of lactoferrin from milk of different species: calorimetric and antimicrobial studies.  

PubMed

Lactoferrin (LF) is an iron-binding glycoprotein found in different biological fluids of mammals and in neutrophils. It has been proposed to be involved in many functions, including protection from pathogens. In this work, purification of lactoferrin using an ion-exchange chromatography (SP-Sepharose) was attempted for the milk of the following animals: sheep (Ovis aries), goat (Capra hircus), camel (Camelus bactrianus), alpaca (Lama pacos), elephant (Elephas maximus) and grey seal (Halichoerus grypus), as well as human (Homo sapiens). Lactoferrin was identified in all the milks apart from that from grey seal. The thermal stability of the purified lactoferrins, in their native and iron-saturated forms, was studied by differential scanning calorimetry (DSC). Maximum temperature, onset temperature and enthalpy change of denaturation were higher when lactoferrins were saturated with iron than in their native form, indicating an increase in the stability of the protein structure upon iron-binding. Human lactoferrin was found to be the most heat-resistant and the other lactoferrins presented different degrees of thermoresistance, that of elephant being the least resistant. The antimicrobial activity of the different isolated lactoferrins was investigated against Escherichia coli 0157:H7. The minimal inhibitory concentrations (MICs) were determined by measuring the absorbance at 620 nm. The minimum bactericidal concentrations (MBCs) were also measured and it was found that camel lactoferrin was the most active lactoferrin against E. coli 0157:H7, whereas alpaca and human lactoferrins were the least active. PMID:18387837

Conesa, Celia; Sánchez, Lourdes; Rota, Carmen; Pérez, María-Dolores; Calvo, Miguel; Farnaud, Sebastien; Evans, Robert W

2008-02-21

242

Structure-energy relationship in barbituric acid: a calorimetric, computational, and crystallographic study.  

PubMed

This paper reports the value of the standard (p(o) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K for barbituric acid. The enthalpies of combustion and sublimation were measured by static bomb combustion calorimetry and transference (transpiration) method in a saturated N2 stream and a gas-phase enthalpy of formation value of -(534.3 +/- 1.7) kJ x mol(-1) was determined at T = 298.15 K. G3-calculated enthalpies of formation are in very good agreement with the experimental value. The behavior of the sample as a function of the temperature was studied by differential scanning calorimetry, and a new polymorph of barbituric acid at high temperature was found. In the solid state, two anhydrous forms are known displaying two out of the six hydrogen-bonding patterns observed in the alkyl/alkenyl derivatives retrieved from the Cambridge Crystallographic Database. The stability of these motifs has been analyzed by theoretical calculations. X-ray powder diffraction technique was used to establish to which polymorphic form corresponds to the commercial sample used in this study and to characterize the new form at high temperature. PMID:18646743

Roux, María Victoria; Temprado, Manuel; Notario, Rafael; Foces-Foces, Concepción; Emel'yanenko, Vladimir N; Verevkin, Sergey P

2008-07-23

243

Calorimetric studies of Cu-Li, Li-Sn, and Cu-Li-Sn  

PubMed Central

Integral molar enthalpies of mixing were determined by drop calorimetry for Cu–Li–Sn at 1073 K along five sections xCu/xSn ? 1:1, xCu/xSn ? 2:3, xCu/xSn ? 1:4, xLi/xSn ? 1:1, and xLi/xSn ? 1:4. The integral and partial molar mixing enthalpies of Cu–Li and Li–Sn were measured at the same temperature, for Li–Sn in addition at 773 K. All binary data could be described by Redlich–Kister-polynomials. Cu–Li shows an endothermic mixing effect with a maximum in the integral molar mixing enthalpy of ?5300 J · mol?1 at xCu = 0.5, Li–Sn an exothermic minimum of ? ?37,000 J · mol?1 at xSn ? 0.2. For Li–Sn no significant temperature dependence between 773 K and 1073 K could be deduced. Our measured ternary data were fitted on the basis of an extended Redlich–Kister–Muggianu model for substitutional solutions. Additionally, a comparison of these results to the extrapolation model of Chou is given.

Furtauer, S.; Tserenjav, E.; Yakymovych, A.; Flandorfer, H.

2013-01-01

244

Thermodynamic properties of autunite, uranyl hydrogen phosphate, and uranyl orthophosphate from solubility and calorimetric measurements  

SciTech Connect

In this study, we use solubility and oxide melt solution calorimetry measurements to determine the thermodynamic properties of the uranyl phosphate phases autunite (abbreviated: CaUP), uranyl hydrogen phosphate (HUP), and uranyl orthophosphate (UP). Solubility measurements from both supersaturated and undersaturated conditions, as well as under different pH conditions, rigorously demonstrate attainment of equilibrium and yield well-constrained solubility product values of -48.36 (-0.03 /+ 0.03), -13.17 (-0.11 / +0.07), and -49.36 (-0.04 / +0.02) for CaUP, HUP, and UP, respectively. We use the solubility data to calculate standard state Gibbs free energies of formation for all phases (-7630.61 ± 9.69, -3072.27 ± 4.76, and -6138.95 ± 12.24 kJ mol-1 for CaUP, HUP, and UP, respectively), and calorimetry data to calculate standard state enthalpies of formation of -3223.22 ± 4.00 and -7001.01 ± 15.10 kJ mol-1 for HUP and UP, respectively. Combining these results allows us also to calculate the standard state entropies of formation of -506.54 ± 10.48 and -2893.12 ± 19.44 kJ mol-1 K-1 for HUP and UP phases, respectively. The results from this study are part of a combined effort to develop reliable and internally consistent thermodynamic data for environmentally relevant uranyl minerals. Data such as these are required in order to optimize and quantitatively assess the effect of phosphate amendment remediation technologies for uranium contaminated systems.

Gorman-Lewis, Drew; Shareva, Tatiana; kubatko, Karrie-Ann; burns, Peter; Wellman, Dawn M.; McNamara, Bruce K.; szymanowski, jennifer; Navrotsky, Alexandra; Fein, Jeremy B.

2009-10-01

245

Concurrent calorimetric and interferometric studies of steady-state natural convection from miniaturized horizontal single plate-fin systems and plate-fin arrays  

NASA Astrophysics Data System (ADS)

Concurrent calorimetric and interferometric studies have been conducted to investigate the effect that reduction of the base-plate dimensions has on the steady-state performance of the rate of natural convection heat transfer from miniaturized horizontal single plate-fin systems and plate-fin arrays. The effect was studied through comparison of the present results with those of earlier relevant calorimetric, interferometric, or numerical studies. Results shown that a reduction of the base-plate area by 74% increased natural convection coefficient by 1.5 times to 26.0 W m-2 K-1 for single fin systems and by 1.8 times to 18 W m-2 K-1 for fin arrays in the range of the base-plate temperature excess of 20-50°C. A simple correlation for the Nusselt number of miniaturized horizontal plate-fin arrays is proposed in the range of Rayleigh number divided by the number of fins to the 2.7 power from 2 × 10 to 5 × 105.

Harahap, Filino; Lesmana, Herry; Sambegoro, Poetro Lebdo

2010-10-01

246

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

PubMed Central

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.

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

1997-01-01

247

Ground calorimetric studies using the REMS ground temperature sensor and the Curiosity rover  

NASA Astrophysics Data System (ADS)

The REMS instrument, on board the Curiosity rover, has an infrared ground temperature sensor that allows monitoring the diurnal evolution of the ground temperature every day at the different sites visited by the rover during its operation on Gale crater. The amplitude of the diurnal ground temperature oscillation depends on the local column of dust, as well as on the thermal inertia (I) of the ground. The rover has a hot Radiosotope Thermal Generator (RTG) of which the temperature is monitored by engineering sensors. This element is an unavoidable extra source of heat that irradiates the ground where the rover stands. Whenever the rover moves and samples a new site the sensed temperature shows a significant drop that ranges between 3 and 15 K depending on the location and time of the day. This drop is the increment of temperature (?T) caused by the heat (q) emited by the RTG source alone, and thus the soil heat capacity (C) can be obtained by rating these magnitudes and allowing the rover to perform in situ ground calorimetry in a simple way: - The heat emited by the RTG can be evaluated using the Stefan Boltzman law (q=?T4) - The soil heat capacity scales with the square of the termal inertial ( C ~ I2) Orbitally determined inertias in the region of the rover [Fergason et al., 2012 ] range from 250 (J/m2K s1/2 ) to 410 (J/m2K s1/2). Thus in the area explored by the rover I may vary a factor 2, which leads to a factor 4 increment in C and thus the final ground offset induced by the RTG extra heating is expected to be significantly greater for soils of higher thermal inertia. Once the rover stands at a fixed position the ground is heated up as the ground responses in time to the irradiated heat until a new equilibrium temperature is reached. Soils with low thermal inertia respond faster to the RTG heating source (around 40 minutes) whereas high thermal inertia soils respond more slowly (around 75 minutes). This method shall be improved for future calorimetry campaigns during the two years of nominal operation of the rover curiosity on Mars.

Zorzano, María-Paz; Martín-Torres, Francisco Javier; Newman, Claire; de la Torre, Manuel; Hamilton, Victoria; Sebastian, Eduardo; Javier Gómez-Elvira, REMS Team; the MSL Science Team

2013-04-01

248

Enthalpies and entropies of proton and cadmium adsorption onto Bacillus subtilis bacterial cells from calorimetric measurements  

NASA Astrophysics Data System (ADS)

We used titration calorimetry to measure the bulk heats of proton and Cd adsorption onto a common Gram positive soil bacterium Bacillus subtilis at 25.0 °C. Using the 4-site non-electrostatic model of Fein et al. [Fein, J.B., Boily, J.-F., Yee, N., Gorman-Lewis, D., Turner, B.F., 2005. Potentiometric titrations of Bacillus subtilis cells to low pH and a comparison of modeling approaches. Geochim. Cosmochim. Acta69 (5), 1123 1132.] to describe the bacterial surface reactivity to protons, our bulk enthalpy measurements can be used to determine the following site-specific enthalpies of proton adsorption for Sites 1 4, respectively: -3.5 ± 0.2, -4.2 ± 0.2, -15.4 ± 0.9, and -35 ± 2 kJ/mol, and these values yield the following third law entropies of proton adsorption onto Sites 1 4, respectively: +51 ± 4, +78 ± 4, +79 ± 5, and +60 ± 20 J/mol K. An alternative data analysis using a 2-site Langmuir Freundlich model to describe proton binding to the bacterial surface (Fein et al., 2005) resulted in the following site-specific enthalpies of proton adsorption for Sites 1 and 2, respectively: -3.6 ± 0.2 and -35.1 ± 0.3 kJ/mol. The thermodynamic values for Sites 1 3 for the non-electrostatic model and Site 1 of the Langmuir Freundlich model of proton adsorption onto the bacterial surface are similar to those associated with multifunctional organic acid anions, such as citrate, suggesting that the protonation state of a bacterial surface site can influence the energetics of protonation of neighboring sites. Our bulk Cd enthalpy data, interpreted using the 2-site non-electrostatic Cd adsorption model of Borrok et al. [Borrok, D., Fein, J.B., Tischler, M., O’Loughlin, E., Meyer, H., Liss, M., Kemner, K.M., 2004b. The effect of acidic solutions and growth conditions on the adsorptive properties of bacterial surfaces. Chem. Geol.209 (1 2), 107 119.] to account for Cd adsorption onto B. subtilis, yield the following site-specific enthalpies of Cd adsorption onto bacterial surface Sites 2 and 3, respectively: -0.2 ± 0.4 and +14.4 ± 0.9 kJ/mol, and the following third law entropies of Cd adsorption onto Sites 2 and 3, respectively: +57 ± 4 and +128 ± 5 J/mol K. The calculated enthalpies of Cd adsorption are typical of those associated with Cd complexation with anionic oxygen ligands, and the entropies are indicative of inner sphere complexation by multiple ligands. The experimental approach described in this study not only yields constraints on the molecular-scale mechanisms involved in proton and Cd adsorption reactions, but also provides new thermodynamic data that enable quantitative estimates of the temperature dependence of proton and Cd adsorption reactions.

Gorman-Lewis, Drew; Fein, Jeremy B.; Jensen, Mark P.

2006-10-01

249

Micromechanical calorimetric sensor  

DOEpatents

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.

Thundat, Thomas G. (Knoxville, TN); Doktycz, Mitchel J. (Knoxville, TN)

2000-01-01

250

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

SciTech Connect

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}.

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

1999-02-10

251

Thioglycolic acid grafted onto silica gel and its properties in relation to extracting cations from ethanolic solution determined by calorimetric technique  

Microsoft Academic Search

Thioglycolic acid was immobilized onto silica gel surface using 3-aminopropyltrimethoxysilane as precursor silylating agent to yield silica. The amount of thioglycolic acid immobilized was 1.03 mmol per gram of silica. This new surface displayed a chelating moiety containing nitrogen, sulfur, and oxygen basic centers which are potentially capable of extracting cations from ethanolic solution, such as MCl3 (M=Fe, Cr, and Mo).

Luiza N. H Arakaki; José G. P Esp??nola; Maria G da Fonseca; Severino F de Oliveira; Antonio N de Sousa; Tomaz Arakaki; Claudio Airoldi

2004-01-01

252

Superconductivity in the misfit compound of (LaSe)1.14(NbSe2): STM/S, calorimetric and magnetization studies  

NASA Astrophysics Data System (ADS)

(LaSe)1.14(NbSe2) is a low temperature superconductor with Tc around 1.2 K belonging to the family of the lamellar chalcogenides. Electron transfer from the LaSe to the NbSe2 slab results in a natural layered system of the insulating LaSe and (super) conducting NbSe2 sheets. In our previous investigations of the anisotropic transport [P. Szabó et al., Phys. Rev. Lett. 86, 5990 (2001)] indications have been found that this system behaves as a stack of Josephson-coupled superconducting NbSe2 sheets separated by insulating LaSe layers. We test this hypothesis by STM/S measurements at subkelvin temperatures and in magnetic fields. Superconducting energy gap obtained by STM opens at the same temperature and field where the interlayer resistivity starts to increase before drop to zero value. Before any conclusions are made homogeneity of the superconducting parameters is to be tested. STM indicates large areas without any gap but calorimetric measurements have shown the bulk superconductivity and magnetization revealed extremely low pinning.

Samuely, P.; Szabo, P.; Kacmarcik, J.; Pribulova, Z.; Samuely, T.; Rodrigo, J. G.; Marcenat, C.; Klein, T.; Cario, L.

2013-03-01

253

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

PubMed

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

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

2012-02-17

254

Solid–solute phase equilibria in aqueous solution. XVI. Thermodynamic properties of malachite and azurite—predominance diagrams for the system Cu 2 + – H 2 O– CO 2  

Microsoft Academic Search

The thermodynamic properties of the copper carbonates malachite, Cu 2(OH)2 CO 3, and azurite, Cu 3(OH) 2(CO 3)2, have been obtained from solubility measurements as a function of temperature as well as ionic strength of aqueous perchlorate media. First, solubility constants have been determined from T= 288.15 K toT= 338.15 K at constant ionic strength, I= 1.00 mol · kg?1NaClO

Wolfgang Preis; Heinz Gamsjäger

2002-01-01

255

Calorimetric and computational study of 2H-1, 4-benzoxazin-3(4H)-one and of related species  

NASA Astrophysics Data System (ADS)

The standard molar enthalpy of formation in the gas phase of 2H-1,4-benzoxazin-3(4H)-one was derived from the standard energy of combustion determined by static bomb combustion calorimetry in oxygen atmosphere and from the standard sublimation enthalpy determined by Calvet microcalorimetry. In addition, we report the results of a systematic theoretical study of the keto and enol tautomers in benzoxazinones and diones using density functional theory. The keto tautomers are computed to be more stable than the enols. Tautomerization energies are reported.

Agostinha, M.; Matos, R.; Miranda, Margarida S.; Morais, Victor M. F.; Liebman, Joel F.

256

Development of alternate cut-flower rose greenhouse temperature set-points based on calorimetric plant tissue evaluation  

Microsoft Academic Search

Energy utilization for heating is one of the most expensive greenhouse climate control operations. The temperature set-point is determined by many interrelated environmental, physiological, and economic factors but is fundamentally driven by the required growth rate of the plant or crop for quality and profitability. Temperatures are maintained to maximize production and affect timing of harvest of greenhouse-grown crops. In

Michael Raviv; Shlomit Medina; Ceasara Wendin; J. Heinrich Lieth

2010-01-01

257

The neutral oxygen donor in complexes of lead and cadmium: A differential pulse polarographic, potentiometric and calorimetric study  

Microsoft Academic Search

Differential pulse polarography has been used to determine the formation constants of PbII with ethylenediamine (en) at ionic strength 0.1 M and 5, 25 and 50°C. The equilibria between Pb2+ and the ligands en and OH? are established rapidly on the polarographic time scale for all complexes studied, so that one peak is observed, that for the metal ion and

Ignacy Cukrowski; Fabrizio Marsicano; Robert D. Hancock; Pulane T. Tshetlho; Willem A. L. Van Otterlo

1995-01-01

258

Calorimetric studies of interactions of some peptides with electrolytes, urea and ethanol in water at 298.15 K  

Microsoft Academic Search

The standard molar enthalpies of solution at infinite dilution $$ \\\\Updelta_{\\\\text{sol}} H_{\\\\text{m}}^{\\\\infty } $$ of glycylglycine, dl-alanyl-dl-alanine and glycylglycylglycine in aqueous solutions of potassium chloride and ethanol as well as of glycylglycine and glycylglycylglycine\\u000a in the solutions containing urea and water have been determined by calorimetry at the temperature 298.15 K. Changes of solution\\u000a enthalpy, expressed in a form so-called heterotactic

Henryk PiekarskiBo; Bo?enna Nowicka

2010-01-01

259

In vitro activity of gallium maltolate against Staphylococci in logarithmic, stationary, and biofilm growth phases: comparison of conventional and calorimetric susceptibility testing methods.  

PubMed

Ga(3+) is a semimetal element that competes for the iron-binding sites of transporters and enzymes. We investigated the activity of gallium maltolate (GaM), an organic gallium salt with high solubility, against laboratory and clinical strains of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), methicillin-susceptible Staphylococcus epidermidis (MSSE), and methicillin-resistant S. epidermidis (MRSE) in logarithmic or stationary phase and in biofilms. The MICs of GaM were higher for S. aureus (375 to 2000 microg/ml) than S. epidermidis (94 to 200 microg/ml). Minimal biofilm inhibitory concentrations were 3,000 to >or=6,000 microg/ml (S. aureus) and 94 to 3,000 microg/ml (S. epidermidis). In time-kill studies, GaM exhibited a slow and dose-dependent killing, with maximal action at 24 h against S. aureus of 1.9 log(10) CFU/ml (MSSA) and 3.3 log(10) CFU/ml (MRSA) at 3x MIC and 2.9 log(10) CFU/ml (MSSE) and 4.0 log(10) CFU/ml (MRSE) against S. epidermidis at 10x MIC. In calorimetric studies, growth-related heat production was inhibited by GaM at subinhibitory concentrations; and the minimal heat inhibition concentrations were 188 to 4,500 microg/ml (MSSA), 94 to 1,500 microg/ml (MRSA), and 94 to 375 microg/ml (MSSE and MRSE), which correlated well with the MICs. Thus, calorimetry was a fast, accurate, and simple method useful for investigation of antimicrobial activity at subinhibitory concentrations. In conclusion, GaM exhibited activity against staphylococci in different growth phases, including in stationary phase and biofilms, but high concentrations were required. These data support the potential topical use of GaM, including its use for the treatment of wound infections, MRSA decolonization, and coating of implants. PMID:19805560

Baldoni, Daniela; Steinhuber, Andrea; Zimmerli, Werner; Trampuz, Andrej

2009-10-05

260

Calorimetrically measured enthalpies for the reaction of H[sub 2] (g) with Zr and Zr alloys  

SciTech Connect

The enthalpy for the direct reaction of H[sub 2] (g) with Zr has been measured by calorimetry at moderate, 323 K, and elevated, 928 K, temperatures over a large range of H contents. The elevated temperature enthalpies were determined for solution in the [alpha] phase, for the ([alpha] + [beta]) phases, the [beta] phase, the ([beta] + [gamma]) phases, and the [gamma] phase. Simultaneously, the equilibrium pressures were measured. A combination of [Delta]G[sub H] = 1/2RT ln p[sub H[sub 2

Dantzer, P. (CNRS-URA, Orsay (France)); Luo, W. (Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science); Flanagan, T.B.; Clewley, J.D. (Univ. of Vermont, Burlington, VT (United States))

1993-07-01

261

First stars. XVI. HST/STIS abundances of heavy elements in the uranium-rich metal-poor star CS 31082-001  

NASA Astrophysics Data System (ADS)

Context. The origin and site(s) of the r-process nucleosynthesis is(are) still not known with certainty, but complete, detailed r-element abundances offer our best clues. The few extremely metal-poor (EMP) stars with large r-element excesses allow us to study the r-process signatures in great detail, with minimal interference from later stages of Galactic evolution. CS 31082-001 is an outstanding example of the information that can be gathered from these exceptional stars. Aims: Here we aim to complement our previous abundance determinations for third-peak r-process elements with new and improved results for elements of the first and second r-process peaks from near-UV HST/STIS and optical UVES spectra. These results should provide new insight into the nucleosynthesis of the elements beyond iron. Methods: The spectra were analyzed by a consistent approach based on an OSMARCS LTE model atmosphere and the Turbospectrum spectrum synthesis code to derive abundances of heavy elements in CS 31082-001, and using updated oscillator strengths from the recent literature. Synthetic spectra were computed for all lines of the elements of interest to check for proper line intensities and possible blends in these crowded spectra. Our new abundances were combined with the best previous results to provide reliable mean abundances for the first and second-peak r-process elements. Results: We present new abundances for 23 neutron-capture elements, 6 of which - Ge, Mo, Lu, Ta, W, and Re - have not been reported before. This makes CS 31082-001 the most completely studied r-II star, with abundances for a total of 37 neutron-capture elements. We also present the first NLTE+3D abundance of lead in this star, further constraining the nature of the r-process. Based on observations made with the NASA/ESA Hubble Space Telescope (HST) through the Space Telescope Science Institute, operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555; and with the ESO Very Large Telescope at Paranal Observatory, Chile; Progr. ID 165.N-0276.Appendix A is available in electronic form at http://www.aanda.org

Siqueira Mello, C.; Spite, M.; Barbuy, B.; Spite, F.; Caffau, E.; Hill, V.; Wanajo, S.; Primas, F.; Plez, B.; Cayrel, R.; Andersen, J.; Nordström, B.; Sneden, C.; Beers, T. C.; Bonifacio, P.; François, P.; Molaro, P.

2013-02-01

262

Caltech Faint Galaxy Redshift Survey. XVI. The Luminosity Function for Galaxies in the Region of the Hubble Deep Field-North to z=1.5  

NASA Astrophysics Data System (ADS)

We have carried out a study of the luminosity function (LF) of galaxies in the region of the Hubble Deep Field-North using our very complete redshift catalog. We divide the sample into five redshift bins covering the range 0.01determinations. We then fix ? to obtain values of L* for each galaxy spectral grouping as a function of redshift. We find that galaxies with strong absorption lines become brighter with z with Q~0.6 at all rest-frame bands studied here, where Q=?log[L*(z)]/?z, while galaxies with detectable emission lines (i.e., star-forming galaxies) show a smaller change in L* with redshift at all bands, Q~0.3, with Q becoming significantly larger at rest-frame 2400 Å. Passive evolution models of galaxies are in reasonable agreement with these results for absorption-line-dominated galaxies, while plausible star formation histories can reproduce the behavior of the emission-line galaxies. We find a constant comoving number density and stellar mass in galaxies out to z~1.05. By stretching all the correction factors applied to the galaxy counts in the highest redshift bin to their maximum possible values, we can just barely achieve this between z=1.05 and 1.3. The major epoch(s) of star formation and of galaxy formation must have occurred even earlier. The UV luminosity density, an indicator of the star formation rate, has increased by a factor of ~4 over the period z=0-1. Based in large part on observations obtained at the W. M. Keck Observatory, which is operated jointly by the California Institute of Technology, the University of California, and NASA.

Cohen, Judith G.

2002-03-01

263

Application of the finite element simulation method to the adiabatic and potentiometric corrections of calorimetric titration data.  

PubMed

A general numerical analysis procedure is described which has been applied to an automated differential pH-thermal titration apparatus operated isoperibolically to obtain thermal corrections for heat loss. It is based on the Direct Byte (D-B) finite element computer simulation technique (FEST) applied to the heat conduction behavior of the instrument with time. Thermal constants of the numerical model are determined, and the results of the correction for titration data obtained from acid-base runs show that a constant upper baseline is achieved using this technique for both fast and slow reactions to an accuracy of 2%. The method is equally valid for endothermic and exothermic reactions. PMID:3998381

Davids, N; Berger, R L; Marini, M A

1985-03-01

264

Calorimetric and computational study of 1,4-dithiacyclohexane 1,1-dioxide (1,4-dithiane sulfone).  

PubMed

This work reports the enthalpies of formation in the condensed and gas state of 1,4-dithiacyclohexane 1,1-dioxide (1,4-dithiane sulfone, 5), derived from the enthalpy of combustion in oxygen, measured by a rotating bomb calorimeter and the variation of vapor pressures with temperatures determined by the Knudsen effusion technique. The theoretically estimated enthalpy of formation was calculated from high-level ab initio molecular orbital calculations at the G2(MP2) level. The theoretical calculations appear to be in very good agreement with experiment. A comparison of the conversion of thiane sulfone 3 to 1,3-dithiane sulfone 4 and 1,4-dithiane sulfone 5 clearly shows the 1,3 isomer to be 6.7 kJ mol(-1) less stable, probably owing to diminished electrostatic repulsion between the sulfur heteroatoms in 1,4-sulfone 5. PMID:16555808

Roux, María Victoria; Temprado, Manuel; Jiménez, Pilar; Notario, Rafael; Guzman-Mejía, Ramón; Juaristi, Eusebio

2006-03-31

265

Calorimetric and thermal decomposition kinetic study of Tb(Tyr)(Gly) 3 Cl 3 ·3H 2 O  

Microsoft Academic Search

The solid-state ternary complex of terbium chloride with L-tyrosine and glycine, [Tb(Tyr)(Gly)3Cl3·3H2O], was synthesized and characterized. Using a solution-reaction isoperibol calorimeter, the enthalpy of reaction for the following reaction, TbCl3·6H2O(s)+Tyr(s)+3Gly(s)=Tb(Tyr)(Gly)3Cl3·3H2O(s)+3H2O(l), was determined to be (5.1±0.6) kJ mol-1. The standard enthalpy of formation of Tb(Tyr)(Gly)3Cl3-3H2O at T=298.15 K has been derived as -(4267.3±2.3) kJ mol-1. The thermal decomposition kinetics of the

Z. H. Zhang; Z. J. Ku; H. R. Li; Y. Liu; S. S. Qu

2005-01-01

266

Spectrophotometric and Calorimetric Studies of U(VI) Complexation with Sulfate at 25-70oC  

SciTech Connect

Sulfate, one of the inorganic constituents in the groundwater of nuclear waste repository, could affect the migration of radioactive materials by forming complexes. Spectrophotometric and microcalorimetric titrations were performed to identify the U(VI)/sulfate complexes and determine the equilibrium constants and enthalpy of complexation at 25-70 C. Results show that U(VI) forms moderately strong complexes with sulfate, i.e., UO{sub 2}SO{sub 4}(aq) and UO{sub 2}(SO{sub 4}){sub 2}{sup 2-}, in this temperature range and the complexes become stronger as the temperature is increased: 2-fold and 10-fold increases in the stability constants of UO{sub 2}SO{sub 4}(aq) and UO{sub 2}(SO{sub 4}{sub 2}{sup 2-}), respectively, when the temperature is increased from 25 C to 70 C. The complexation is endothermic and entropy-driven, showing typical characteristics of inner-sphere complexation and 'hard acid'/'hard base' interactions. The thermodynamic trends are discussed in terms of dehydration of both the cation (UO{sub 2}{sup 2+}) and the anion (SO{sub 4}{sup 2-}) as well as the effect of temperature on the structure of water.

Tian, Guoxin; Rao, Linfeng

2008-10-30

267

A calorimetric study of energy conversion efficiency of a sonochemical reactor at 500 kHz for organic solvents.  

PubMed

It would seem that the economic viability is yet to be established for a great number of sonochemical processes, owning to their perfectible ultrasonic equipments. Industrial scale sonoreactors may become more important as a result of mastering the parameters with influence on their energy balance. This work related the solvent type to the energy efficiency as the first step of a complex study aiming to assess the energy balance of sonochemical reactors at 500 kHz. Quantitative measurements of ultrasonic power for water and 10 pure organic solvents were performed by calorimetry for a cylindrically shaped sonochemical reactor with a bottom mounted vibrating plate. It was found that the ultrasonic power is strongly related to the solvent, the energy conversion for organic liquids is half from that of water and there is a drop in energy efficiency for filling levels up to 250 mm organic solvents. Surface tension, viscosity and vapor pressure influence the energy conversion for organic solvents, but it is difficult explain these findings based on physical properties of solvents alone. The apparent intensity of the atomization process shows a good agreement with the experimentally determined values for energy conversion for water and the solvent group studied here. This study revealed that to attain the same ultrasonic power level, more electrical energy is need for organic solvents as compared to water. The energy balance equation has been defined based on these findings by considering an energy term for atomization. PMID:20655791

Toma, Maricela; Fukutomi, Satoshi; Asakura, Yoshiyuki; Koda, Shinobu

2010-05-24

268

Oxygen flow calorimeter for determining the heating value of kilogram size samples of municipal solid waste  

SciTech Connect

A calorimeter to determine the enthalpies of combustion of kilogram size samples of minimally processed municipal solid municipal waste (MSW) in flowing oxygen near atmospheric pressure is discussed. The organic fraction of 25 gram pellets of highly processed MSW was burned in pure oxygen to CO/sub 2/ and H/sub 2/O in a small prototype calorimeter. The carbon content of the ash and the uncertainty in the amount of CO in the combustion products contribute calorimetric errors of 0.1 percent or less to the enthalpy of combustion. Large pellets of relatively unprocessed MSW have been successfully burned in a prototype kilogram size combustor at a rate of 15 minutes per kilogram with CO/CO/sub 2/ ratios not greater than 0.1 percent. The design of the kilogram size calorimeter was completed and construction was begun.

Domalski, E.S.; Churney, K.L.; Ledford, A.E.; Ryan, R.V.; Reilly, M.L.

1982-02-01

269

Surfactant loss control in chemical flooding: Spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Quarterly technical progress report, January 1, 1994--March 31, 1994.  

National Technical Information Service (NTIS)

Since surfactants are often present as mixtures, effort is being made to understand the synergetic and competitive forces involving determining adsorption of surfactants from their mixtures. Adsorption of tetradecyl trimethyl ammonium chloride (TTAC) and ...

P. Somasundaran

1994-01-01

270

Calorimetric determination of enthalpy changes for proton ionization of N-[2-hydroxyethyl]piperazine- N?-[2-ethane sulfonic acid] (HEPES) and N-[2-hydroxyethyl]piperazine- N?-[2-hydroxypropane sulfonic acid] (HEPPSO) in water–methanol mixtures  

Microsoft Academic Search

Enthalpies for the two proton ionizations of the biochemical buffers N-[2-hydroxyethyl]piperazine-N?-[2-ethane sulfonic acid] (HEPES) and N-[2-hydroxyethyl]piperazine-N?-[2-hydroxypropane sulfonic acid] (HEPPSO) were obtained in water–methanol mixtures with methanol mole fraction (Xm) from 0 to 0.360. With increasing methanol, the ionization enthalpy for the first proton (?H1) of HEPES increased steadily from 8.4 to 15.3kJmol?1 whereas that for HEPPSO rose to a maximum

F. H. Jumean; N. M. Abdo

2006-01-01

271

Surfactant loss control in chemical flooding: Spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Quarterly technical progress report, October 1, 1993December 31, 1993  

Microsoft Academic Search

The aim of this contract is to elucidate the mechanisms underlying adsorption and surface precipitation of flooding surfactants on reservoir minerals. Effect of surfactant structure, surfactant combinations and other inorganic and polymeric species and solids of relevant mineralogy will also be determined. A multi-pronged approach consisting of micro & nano spectroscopy, microcalorimetry, electrokinetics, surface tension and wettability win be used

Somasundaran

1994-01-01

272

Dioxouranium(VI)-carboxylate complexes. A calorimetric and potentiometric investigation of interaction with oxalate at infinite dilution and in NaCl aqueous solution at I=1.0 mol L(-1) and T=25 degrees C.  

PubMed

In this paper we investigated the interactions between dioxouranium(VI) and oxalate using (H(+)-glass electrode) potentiometry and titration calorimetry. Potentiometric measurements were carried out in NaCl aqueous solutions and at T=25 degrees C in a wide range of experimental conditions (concentrations, ligand/metal molar ratio, pH, titrants) at low ionic strength values (I< or =0.090mol L(-1), without supporting electrolyte) and at I=1.0mol L(-1); different procedures were employed for the acquisition of experimental data and careful analysis of these data performed. In all cases the speciation model that best fits experimental data takes into account the formation of the binary mononuclear species UO(2)(ox)(0), UO(2)(ox)(2)(2-), UO(2)(ox)(3)(4-) widely reported in literature, the ternary hydroxyl mononuclear species UO(2)(ox)OH(-), UO(2)(ox)(OH)(2)(2-), UO(2)(ox)(2)OH(3-), UO(2)(ox)(3)OH(5-), the protonated ternary mononuclear species UO(2)(ox)(3)H(3-) and the binuclear species (UO(2))(2)(ox)(5)(6-). Calorimetric measurements were carried out following similar procedures and in the same experimental conditions as employed for the potentiometric measurements at I=1.0mol L(-1) in NaCl. The stability of UO(2)(2+)-oxalate(2-) complexes is fairly high and their main contribution to stability is entropic in nature. Some linear empirical relationships were found which make it possible to calculate (i) the contribution of a single bond: DeltaG(sb) degrees =-16.6+/-0.2kJ mol(-1) and TDeltaS(sb) degrees =16.2+/-0.5kJ mol(-1); (ii) chelate stabilisation per ring: DeltaG(r) degrees =-1.30+/-0.04kJ mol(-1) and TDeltaS(r) degrees =1.27+/-0.23kJ mol(-1) and (iii) the mean stability of negatively charged Na(+)-ion pair complexes: log(T)K=(0.46+/-0.02).|z| (z=charge of complex species), DeltaG degrees =-(2.60+/-0.1).|z|kJ mol(-1) and TDeltaS degrees =2.5+/-0.5kJ mol(-1). Both potentiometric and calorimetric results provide evidence of the penta-coordination of the species UO(2)(ox)(3)(4-). SIT parameters were calculated from the data at I=0 and I=1.02mol kg(-1). Comparisons are made with literature data. An insoluble dioxouranium(VI) ternary complex was synthesised (at I=1.0mol L(-1) in NaCl) and characterised by thermoanalysis and elemental analysis. PMID:19071399

Crea, Francesco; De Robertis, Alessandro; De Stefano, Concetta; Sammartano, Silvio

2006-07-07

273

Calorimetric studies of the heats of protonation of the metal in cis-M(CO)[sub 2](bidentate phosphine)[sub 2] complexes of chromium, molybdenum, and tungsten  

SciTech Connect

Titration calorimetry has been used to determine the heats of protonation ([Delta]H[sub HM]) of cis-M(CO)[sub 2](L-L)[sub 2] complexes (M = Cr, Mo, W; L-L = dppm, dppe, dppp, arphos, dmpe) with CF[sub 3]SO[sub 3]H in 1,2 dichloroethane solvent at 25C. Spectroscopic studies show that protonation occurs at the metal center to form [M(H)(CO)[sub 2](L-L)[sub 2

Sowa, J.R. Jr.; Bonanno, J.B.; Zanotti, V.; Angelici, R.J. (Iowa State Univ., Ames (United States))

1992-04-15

274

Polymorphism of 2-nitroaniline studied by calorimetric (DSC), structural (X-ray diffraction) and spectroscopic (FT-IR, Raman, UV–Vis) methods  

Microsoft Academic Search

The separation and growth methods of three ortho-nitroaniline (o-NA) polymorphs were found. The irreversible character of the ??? and ??? phase transitions was revealed by differential scanning calorimetry (DSC) measurements and microscopic hot stage observations. The X-ray structure of the ?-form was determined and compared with the ? phase structure solved by Daneshwar et al. [N.N. Daneshwar et al. Acta

Tomasz Zych; Tomasz Misiaszek; M. Magdalena Szostak

2007-01-01

275

Dielectric, calorimetric and elastic anomalies associated with the first order I4\\/mcm \\\\leftrightarrow Pbcm phase transition in (Ca, Sr)TiO3 perovskites  

Microsoft Academic Search

Conduction calorimetry has been used to determine with high precision the latent heat and variation in heat capacity which accompany the first order I4\\/mcm \\\\leftrightarrow Pbcm phase transition in perovskites with compositions (Ca1-xSrx)TiO3, x = 0.65, 0.68, 0.74 (CST65, CST68, CST74). In CST65 (CST68), the latent heat is dissipated\\/absorbed over a temperature interval of ~11 K (~6 K), which is

J. Manchado; F. J. Romero; M. C. Gallardo; J. del Cerro; T. W. Darling; P. A. Taylor; A. Buckley; M. A. Carpenter

2009-01-01

276

Determining thermodynamic properties of molecular interactions from single crystal studies.  

PubMed

The concept of single crystals of macromolecules as thermodynamic systems is not a common one. However, it should be possible to derive thermodynamic properties from single crystal structures, if the process of crystallization follows thermodynamic rules. We review here an example of how the stabilizing potentials of molecular interactions can be measured from studying the properties of DNA crystals. In this example, we describe an assay based on the four-stranded DNA junction to determine the stabilizing potentials of halogen bonds, a class of electrostatic interactions, analogous to hydrogen bonds, that are becoming increasing recognized as important for conferring specificity in protein-ligand complexes. The system demonstrates how crystallographic studies, when coupled with calorimetric methods, allow the geometries at the atomic level to be directly correlated with the stabilizing energies of molecular interactions. The approach can be generally applied to study the effects of DNA sequence and modifications of the thermodynamic stability of the Holliday junction and, by inference, on recombination and recombination dependent processes. PMID:23933330

Vander Zanden, Crystal M; Carter, Megan; Ho, Pui Shing

2013-08-06

277

Surfactant loss control in chemical flooding: Spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Quarterly technical progress report. October 1, 1994--December 31, 1994  

SciTech Connect

The aim of this research is to elucidate the mechanisms underling adsorption and surface precipitation of flooding surfactants on reservoir minerals. The adsorption and desorption behaviors of tetradecyltrimethyl ammonium chloride (TTAC) and pentadecylethoxylated nonylphenol (NP-15) mixtures as reported earlier were rather complex and to better understand the interactions involved fluorescence spectroscopy and ultrafiltration were used during this report period to probe the microstructure of the adsorbed layer and to determine individual surfactant monomer concentration respectively. It was observed that pyrene was solubilized in mixed aggregates (hemimicelles) of a 1:1 TTAC:NP-15 mixture at the alumina-water interface over a wider concentration range than for TTAC alone. It was also observed that the adsorbed aggregate of a 1:1 TTAC:NP-15 mixture is as hydrophobic as the mixed micelle in solution. This is contrary to what was observed for the adsorption of TTAC alone: pyrene was preferentially solubilized in the TTAC micelles rather than the adsorbed aggregate. The preference of pyrene for the mixed adsorbed aggregates over individual aggregates is relevant to the application of surfactant mixtures in enhanced oil recovery and solubilization. The adsorption/desorption behavior of surfactants is directly related to the monomer concentration of the surfactant, hence it is important to monitor changes in monomer concentration during the adsorption and desorption processes. Ultrafiltration techniques were used to monitor the monomer concentration in solution and at the interface to determine the partitioning of the surfactants to the solid-liquid interface.

Somasundaran, P.

1995-03-01

278

Calorimetric, Viscosimetric, and Light Scattering Studies of the Aggregation of, and the Solubilization of Water by, Triton X-35 in n-Heptane.  

PubMed

The behavior of a nonionic surfactant TX-35 in solution in n-heptane in the presence and absence of added water has been examined using the microcalorimetric, viscosimetric, and quasielastic light scattering experimental methods. In this paper, we were interested in the aggregation process of the poly(oxyethylene) glycol alkylphenyl ether in n-heptane and in the solubilization of water in the reverse micelle of the surfactant (micellar solubilization). The analysis of the differential molar enthalpies of dilution of TX-35 in dried n-heptane has shown the occurrence of a gradual exothermic aggregation process on a very wide range of concentration which takes place at particular concentration so-called "operational CMC". This operational CMC value has been confirmed by viscosities measurements. The differential molar enthalpies of hydration of TX-35 were also measured and found to be exothermic. The maximal hydration ratio (w0) was found to be equal to 3.2 mol H2O per mole of TX-35 before the point of phase separation. The measurements of the variation of the amount of water contained in TX-35 solutions at different concentrations in n-heptane also show the occurence of a gradual aggregation process and confirm the value of the maximal hydration ratio already determined by microcalorimetry. In the absence of added water, from the quasielastic light scattering experiments, a mean diameter of the aggregates close to 45 Å has been determine, while in the presence of water, a mean diameter of 61 Å was detected and remained unchanged with increasing the hydration ratio indicating that the size of the aggregate is more influenced by the presence of water than by the amount. In the presence of water, it is relevant to discuss aggregates of lamellar or filament shape. Copyright 1999 Academic Press. PMID:9885255

Lagerge; Grimberg-Michaud; Guerfi; Partyka

1999-01-15

279

Protection of liposomes against fusion during drying by oligosaccharides is not predicted by the calorimetric glass transition temperatures of the dry sugars  

PubMed Central

Sugars play an important role in the desiccation tolerance of most anhydrobiotic organisms. It has been shown in previous studies that different structural families of oligosaccharides have different efficacies to interact with phospholipid headgroups and protect membranes from solute leakage during drying. Here, we have compared three families of linear oligosaccharides (fructans (inulins), malto-oligosaccharides, manno-oligosaccharides) for their chain-length dependent protection of egg phosphatidylcholine liposomes against membrane fusion. We found increased protection with chain length up to a degree of polymerization (DP) of 5 for malto-oligosaccharides, and a decrease for inulins and manno-oligosaccharides. Differential scanning calorimetry measurements showed that for all sugars the glass transition temperature (Tg) increased with DP, although to different degrees for the different oligosaccharide families. Higher Tg values resulted in reduced membrane fusion only for malto-oligosaccharides below DP5. Contrary to expectation, for inulins, manno-oligosaccharides and malto-oligosaccharides of a DP above five, fusion increased with increasing Tg, indicating that other physical parameters are more important in determining the ability of different sugars to protect membranes against fusion during drying. Further research will be necessary to experimentally define such parameters.

Rennecke, Petra; Oliver, Ann E.

2007-01-01

280

Surfactant loss control in chemical flooding: Spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Annual report, September 30, 1992--September 30, 1993  

SciTech Connect

The aim of this research project is to investigate mechanisms underlying adsorption and surface precipitation of flooding surfactants on reservoir minerals. Effects of surfactant structure, surfactant combinations, various inorganic and polymeric species, and solids mineralogy will be determined. A multi-pronged approach consisting of micro & nano spectroscopy, microcalorimetry, electrokinetics, surface tension and wettability; is used in this study. The results obtained should help in controlling surfactant loss in chemical flooding and in developing optimum structures and conditions for efficient chemical flooding processes. During the first year of this three year contract, adsorption of single surfactants and select surfactant mixtures was studied at the solid-liquid and gas-liquid interfaces. Surfactants studied include alkyl xylene sulfonates, polyethoxylated alkyl phenols, octaethylene glycol mono n-decyl ether, and tetradecyl trimethyl ammonium chloride. Adsorption of surfactant mixtures of varying composition was also investigated. The microstructure of the adsorbed layer was characterized using fluorescence spectroscopy. Changes interfacial properties such as wettability, electrokinetics and stability of reservoir minerals were correlated with the amount of reagent adsorbed. Strong effects of the structure of the surfactant and position of functional groups were revealed.

Somasundaran, P.

1994-07-01

281

Surfactant loss control in chemical flooding spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Annual report, September 30, 1992--September 30 1995  

SciTech Connect

The aim of this research project was to investigate mechanisms governing adsorption and surface precipitation of flooding surfactants on reservoir minerals. Effects of surfactant structure, surfactant combinations, various inorganic and polymeric species, and solids mineralogy have been determined. A multi-pronged approach consisting of micro & nano spectroscopy, electrokinetics, surface tension and wettability is used in this study. The results obtained should help in controlling surfactant loss in chemical flooding and in developing optimum structures and conditions for efficient chemical flooding processes. During the three years contract period, adsorption of single surfactants and select surfactant mixtures was studied at the solid-liquid and gas-liquid interfaces. Alkyl xylene sulfonates, polyethoxylated alkyl phenols, octaethylene glycol mono n-decyl ether, and tetradecyl trimethyl ammonium chloride were the surfactants studied. Adsorption of surfactant mixtures of varying composition was also investigated. The microstructure of the adsorbed layer was characterized using fluorescence spectroscopy. Changes in interfacial properties such as wettability, electrokinetics and stability of reservoir minerals were correlated with the amounts of reagent adsorbed. Strong effects of the structure of the surfactant and position of functional groups were revealed. Changes of microstructure upon dilution (desorption) were also studied. Presence of the nonionic surfactants in mixed aggregate leads to shielding of the charge of ionic surfactants which in turn promotes aggregation but reduced electrostatic attraction between the charged surfactant and the mineral surface. Strong consequences of surfactant interactions in solution on adsorption as well as correlations between monomer concentration in mixtures and adsorption were revealed.

Casteel, J. [Bartlesville Project Office, OK (United States)

1996-07-01

282

Calorimetric and computational study of 3-buten-1-ol and 3-butyn-1-ol. Estimation of the enthalpies of formation of 1-alkenols and 1-alkynols.  

PubMed

The enthalpies of combustion and vaporization of 3-buten-1-ol and 3-butyn-1-ol have been measured by static bomb combustion calorimetry and correlation gas chromatography techniques, respectively, and the gas-phase enthalpies of formation, Delta(f)H degrees (m)(g), have been determined, the values being -147.3 +/- 1.8 and 16.7 +/- 1.6 kJ mol(-1), for 3-buten-1-ol and 3-butyn-1-ol, respectively. High level calculations at the G2 and G3 levels have also been carried out. Relationships between the enthalpies of formation of 1-alkanols, 1-alkenols and 1-alkynols and with the corresponding hydrocarbons have been discussed. From the calculated contributions to Delta(f)H degrees (m)(g) for the substitutions of CH(3) by CH(2)OH, CH(3)CH(2) by CH(2)=CH and CH(3)CH(2) by CH triple bond C, we have estimated the Delta(f)H degrees (m)(g) values for 3-buten-1-ol and 3-butyn-1-ol, in excellent agreement with the experimental ones. Delta(f)H degrees (m)(g) values for 1-alkenols and 1-alkynols up to 10 carbon atoms have also been estimated. PMID:16834161

Vélez, Ederley; Quijano, Jairo; Gaviria, Jair; Roux, María Victoria; Jiménez, Pilar; Temprado, Manuel; Martín-Valcárcel, Gloria; Pérez-Parajón, Juan; Notario, Rafael

2005-09-01

283

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

PubMed

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

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

2008-10-17

284

Virulence Determination  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter reviews the in vitro and in vivo assays that are available for determination of pathogenic potential of Listeria monocytogenes bacteria, highlighting the value of using multiplex PCR for rapid and accurate assessment of listerial virulence....

285

Cyst-based toxicity tests XVI--sensitivity comparison of the solid phase Heterocypris incongruens microbiotest with the Hyalella azteca and Chironomus riparius contact assays on freshwater sediments from Peninsula Harbour (Ontario, Canada).  

PubMed

In view of the complexity and costs of "traditional" whole sediment assays, a "culture/maintenance free" direct contact microbiotest has been developed with the freshwater ostracod Heterocypris incongruens. The new Toxkit assay (named Ostracodtoxkit) has been applied to 33 sediment samples from Peninsula Harbour, located in Lake Superior of the Great Lakes water basin in Ontario, Canada. The microbiotest was applied in parallel to direct contact tests with the amphipod Hyalella azteca and the midge larva Chironomus riparius, to compare its relative sensitivity with that of the two "conventional" assays. The study was undertaken in the framework of remediation action plans for specific areas of concern, to enable decision making by the Canadian authorities for the restoration of impacted aquatic environments. Most sediments were found non-toxic (<20% mortality) to both the conventional test species and the ostracod. For the large majority of samples, a very good correspondence was found between the two crustacean test species for the intensity of the toxic signal "mortality", as reflected by a 0.71 (p<0.05) correlation coefficient. Growth inhibition, which is determined in the ostracod microbiotest as a sublethal effect criterion, allowed the earmarking of some sediment samples, which were apparently more toxic for the amphipod than to the ostracod. For 20% of the samples, substantially higher mortality scores were noted with the ostracod assay than with the midge larvae tests and the overall correlation coefficient between these two tests was lower (r=0.60,p<0.05). The results obtained in the present study corroborate those of previous research on sediments collected from various rivers in Flanders, Belgium, and confirm the potential of the new ostracod microbiotest as a reliable and sensitive low cost alternative for traditional whole sediment assays. PMID:12729691

Belgis, Z Chial; Persoone, Guido; Blaise, Christian

2003-07-01

286

Principer foer Kalorimetriska Bestaemningar av Vaermevaerden (Basic Principles for the Determination of Calorific Values),  

National Technical Information Service (NTIS)

Calorimetric measurements are based on the first law of thermodynamics and Newton's law of cooling. The classification of calorimeters is based on the thermal flow characteristics between the calorimeter proper and its environment (the thermostat or jacke...

M. Mansson

1988-01-01

287

Thermodynamic properties of the forsterite-fayalite (Mg2SiO4-Fe2SiO4) solid solution. determination of heat of formation  

NASA Astrophysics Data System (ADS)

A high temperature calorimetric solution method involving the use of a sodium and lithium metaborate (NaBO2+LiBO2) molten bath at 1,180 K, has been developed in order to measure the enthalpy of formation of the forsterite-fayalite (Mg2SiO4-Fe2SiO4) system. The samples used for these measurements have been obtained by synthesis. They have been carefully controlled by chemical and X-ray analysis and Mössbauer spectroscopy. The results obtained for forsterite and fayalite agree closely with the data commonly found in the literature. Owing to the uncertainty of the experimental results, it is not possible to determine conclusively whether an enthalpy of mixing exists in this system.

Thierry, P.; Chatillon-Colinet, C.; Mathieu, J. C.; Regnard, J. R.; Amossé, J.

1981-02-01

288

Calorimetric particle detectors with superconducting absorber materials  

NASA Astrophysics Data System (ADS)

Massive superconducting absorbers of molybdenum and vanadium are used as low temperature calorimeter particle detectors. The high temperature resolution of the thermometry system, consisting of a superconducting phase transition thermometer monitored with a DC Squid, enables the detection of alpha particles with large single crystals. With a 35 g molybdenum single crystal, an energy resolution of 10 percent Full Width Half Maximum (FWHM) on 5.8 MeV alpha particles is obtained. The observed temperature rise of 1.2 mK is a factor of eight less than expected from the calculated heat capacity. Using a 15g vanadium single crystal, the energy resolution in 5.8 MeV alpha particles is 1.2 percent FWHM. In this case, the pulse height is a factor of five smaller than expected from the calculated heat capacity. A possible reason for the large deviations from the expected heat capacity is the presence of hydrogen dissolved in these transition metals, another reason might be the presence of surface impurities or defects.

Forster, G.; Ferger, P.; Feilitzsch, F. V.; Moessbauer, R. L.; Azgui, F.; Igalson, J.

1991-11-01

289

The CDF level 2 calorimetric trigger upgrade  

SciTech Connect

CDF II upgraded the calorimeter trigger to cope with the higher detector occupancy due to the increased Tevatron instantaneous luminosity ({approx} 2.8 x 10{sup 32} cm{sup -2} s{sup -1}). While the original system was implemented in custom hardware and provided to the L2 trigger a limited-quality jet clustering performed using a reduced resolution measurement of the transverse energy in the calorimeter trigger towers, the upgraded system provides offline-quality jet reconstruction of the full resolution calorimeter data. This allows to keep better under control the dependence of the trigger rates on the instantaneous luminosity and to improve the efficiency and purity of the trigger selections. The upgraded calorimeter trigger uses the general purpose VME board Pulsar, developed at CDF II and already widely used to upgrade the L2 tracking and L2 decision systems. A battery of Pulsars is used to merge and send the calorimeter data to the L2 CPUs, where software-implemented algorithms perform offline-like clustering. In this paper we review the design and the performance of the upgraded system.

Bhatti, A.; /Rockefeller U.; Canepa, A.; /Pennsylvania U.; Casarsa, M.; /INFN, Pisa /Pisa U. /Pisa, Scuola Normale Superiore; Convery, M.; /Fermilab; Cortiana, G.; /Padua U. /INFN, Padua; Dell'Orso, M.; /INFN, Pisa /Pisa U. /Pisa, Scuola Normale Superiore; Donati, S.; /INFN, Pisa /Pisa U. /Pisa, Scuola Normale Superiore; Flanagan, G.; /Purdue U.; Frisch, H.; /Chicago U., EFI; Fukun, T.; /Chicago U., EFI; Krop, D.; /Chicago U., EFI /INFN, Pisa /Pisa U. /Pisa, Scuola Normale Superiore

2009-01-01

290

Calorimetric and computational study of indanones.  

PubMed

Condensed phase standard (p degrees = 0.1 MPa) molar enthalpies of formation for 1-indanone, 2-indanone, and 1,3-indandione were derived from the standard molar enthalpies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpies of sublimation for 1-indanone and 2-indanone, at T = 298.15 K, were measured both by correlation-gas chromatography and by Calvet microcalorimetry leading to a mean value for each compound. For 1,3-indandione, the standard molar enthalpy of sublimation was derived from the vapor pressure dependence on temperature. The following enthalpies of formation in gas phase, at T = 298.15 K, were then derived: 1-indanone, -64.0 +/- 3.8 kJ mol(-1); 2-indanone, -56.6 +/- 4.8 kJ mol(-1); 1,3-indandione, -165.0 +/- 2.6 kJ mol(-1). The vaporization and fusion enthalpies of the indanones studied are also reported. In addition, theoretical calculations using the density functional theory with the B3LYP and MPW1B95 energy functionals and the 6-311G** and cc-pVTZ basis sets have been performed for these molecules and the corresponding one-ring species to obtain the most stable geometries and to access their energetic stabilities. PMID:17929782

Matos, M Agostinha R; Miranda, Margarida S; Monte, Manuel J S; Santos, Luís M N B F; Morais, Victor M F; Chickos, James S; Umnahanant, Patamaporn; Liebman, Joel F

2007-10-11

291

Determining Densities  

NSDL National Science Digital Library

Students will use two different methods to determine the densities of a variety of materials and objects. The first method involves direct measurement of the volumes of objects that have simple geometric shapes, while the second uses the water displacement method to determine the volumes of irregularly-shaped objects. After the densities are determined, students will create x-y scatter graphs of mass versus volume, and these graphs will reveal that objects with densities less than water (floaters) lie above the graphâs diagonal, and those with densities greater than water (sinkers) lie below the diagonal. Pre-requisite Knowledge: * Students should be able to use rulers to measure lengths to the nearest millimeter, triple beam balances to measure masses to at least the nearest 0.1 gram, and graduated cylinders to measure liquids to at least the nearest 1 milliliter. * Students should be able to calculate the volumes of rectangular, cylindrical, and spherical solids. * Students should be able to graph points on an x-y coordinate grid.

Hebrank, Mary R.

2004-01-01

292

Preparation of ethylenediamine-anchored cellulose and determination of thermochemical data for the interaction between cations and basic centers at the solid/liquid interface.  

PubMed

Cellulose was first modified with thionyl chloride, giving 99% substitution at C6, and then reacted with ethylene-1,2-diamine to produce 6-(2'-aminoethylamino)-6-deoxy-cellulose. From the 8.5% of nitrogen incorporated in the polysaccharide backbone, the amount of ethylene-1,2-diamine anchored per gram of modified cellulose was determined to be 3.03+/-0.01mmol. This chemically immobilized surface was characterized by FTIR, TG, (13)C NMR, and SEM techniques. The available basic nitrogen centers covalently bonded to the biopolymer skeleton were studied for copper, cobalt, nickel, and zinc adsorption from aqueous solutions and the respective thermal adsorption effects were determined by calorimetric titration. The ability to adsorb cations gave a capacity order of Co(2+)>Cu(2+)>Zn(2+)>Ni(2+) with affinities of 1.91+/-0.07, 1.32+/-0.07, 1.31+/-0.02, and 1.08+/-0.04mmol/g, respectively. The net thermal effects obtained from calorimetric titration measurements were adjusted to a modified Langmuir equation and the enthalpy of the interaction was calculated to give the following exothermic values: -20.8+/-0.05, -11.72+/-0.03, -7.32+/-0.01, and -6.27+/-0.02kJ/mol for Co(2+), Cu(2+), Zn(2+), and Ni(2+), respectively. With the exception of the entropic value for copper, the other thermodynamic data for these systems are favorable for cation adsorption from aqueous solutions at the solid/liquid interface, suggesting the use of this anchored biopolymer for cation removal from the environment. PMID:17022956

da Silva Filho, Edson C; de Melo, Júlio C P; Airoldi, Claudio

2006-10-04

293

A Low-Temperature Calorimetric Study of Forsterite-Fayalite (Mg2SiO4-Fe2SiO4) Solid Solutions: An Analysis of Vibrational, Magnetic and Electronic Contributions to the Heat Capacity and Entropy of Mixing  

NASA Astrophysics Data System (ADS)

Orthosilicate olivine in the system Mg2SiO4-Fe2SiO4 (forsterite-fayalite) is a major phase in the solar system. It occurs in several types of meteorites and also on different planets and their moons. On Earth, Fe-Mg olivine is the most abundant phase of Earth's upper mantle and is an important mineral in mafic und ultramafic igneous and metamorphic rocks. Knowledge of its thermodynamic properties is crucial for undertaking many mineralogical, petrological and geophysical investigations. The heat capacities (Cp) of a series of synthetic forsterite (Fo)-fayalite (Fa) olivines have been measured between 5 and 300 K on milligram-sized samples using a new calorimetric method - heat pulse calorimetry. Sharp, ?-type Cp-anomalies are observed in the Fe-rich compositions Fa, Fo10Fa90, Fo20Fa80, Fo30Fa70 and Fo40Fa60. The corresponding Neel temperatures TN decrease linearly from 64.5 K in Fa to 32.8 K in Fo40Fa60 following the relationship TN = 79.02*XFa - 14.07. Fo50Fa50 and Mg-richer olivines show weak broad features in the Cp data around 15-20 K that decrease in magnitude with increasing Fo content in olivine. In order to obtain and separate electronic, magnetic and vibrational heat capacity contributions, Cel, Cmag, and Cvib from the experimental Cp's (Ctot), we used a single- parameter phonon dispersion model to calculate Cvib for the solid-solution members. The Cel + Cmag (i.e., Ctot - Cvib) contributions were fit to expressions describing a Schottky-type electronic anomaly and a paramagnetic-antiferromagnetic transition. For Fo50Fa50 and Mg-richer olivines, our analysis of Ctot shows that also these compositions have a Cmag contribution with a maximum around 25 K. Decomposition of the excess heat capacity (?Cp^{xs}) into corresponding electronic, magnetic and vibrational contributions yields the largest absolute values for ?C^{mag,xs}. Excess entropies of mixing, ?S^{xs}, were also calculated from the Cp data. ?S^{mag,xs} at 298.15 K is weakly negative for the solid solution (approx. -2 J/Kmol, because positive and negative Cp contributions as a function of temperature largely cancel each other between 0 and 300 K. ?C^{el,xs} is positive for all temperatures and compositions, ?S^{el,xs} thus gives a positive contribution with a maximum of 0.8 J/Kmol for Fo50Fa50. ?S^{vib,xs} is also slightly positive for most members (maximum of 1.2 J/Kmol for Fo40Fa60). The resulting overall excess entropy, ?S^{xs} = ?S^{vib,xs} + ?S^{el,xs} + ?S^{mag,xs}, at 298.15 K along the Fo-Fa join is zero within 2?-uncertainty.

Dachs, E.; Geiger, C. A.; von Seckendorff, V.; Grodzicki, M.

2006-12-01

294

Speckle Interferometry at the U.S. Naval Observatory. XVI.  

NASA Astrophysics Data System (ADS)

The results of 1031 speckle-interferometric observations of double stars, made with the 26 inch refractor of the U.S. Naval Observatory, are presented. Each speckle-interferometric observation of a system represents a combination of over two thousand short-exposure images. These observations are averaged into 457 mean relative positions and range in separation from 0farcs15 to 16farcs94, with a median separation of 3farcs03. The range in V-band magnitudes for the primary (secondary) of observed targets is 3.1-12.9 (3.2-13.3). This is the sixteenth in a series of papers presenting measurements obtained with this system and covers the period 2009 January 12 through 2009 December 17. Included in these data are 12 older measurements whose positions were previously deemed possibly aberrant, but are no longer classified this way following a confirming observation. Also, 10 pairs with a single observation are herein confirmed. This paper also includes the first data obtained using a new ICCD with fiber optic cables.

Mason, Brian D.; Hartkopf, William I.; Wycoff, Gary L.

2011-05-01

295

Stereotactic radiosurgery XVI: a treatment for previously irradiated pituitary adenomas.  

PubMed

We report the use of stereotactic radiosurgery delivered through an adapted linear accelerator [stereotactic multiple arc radiation therapy (SMART)] for pituitary adenomas not cured by conventional therapy. All 21 patients had undergone conventional radiotherapy (45-50 Gy); 18 had also undergone prior surgery. This cohort comprised 13 patients with somatotrope adenomas, four with corticotrope adenomas, one with a lactotrope adenoma, and three with nonfunctioning pituitary adenomas (median follow-up: 33 months, range: 3-72 months). SMART has proven effective, safe, and rapidly acting. We observed an accelerated reduction in GH and IGF-I levels in acromegaly, with normalization of GH and IGF-I levels in 58%. Mean GH fell from 21.1 mU/liter to 7.9 mU/liter (7 ng/ml to 2.6 ng/ml, P < 0.01, median 25 months) faster than our predicted fall to 50% at 2 yr with conventional radiotherapy. Mean IGF-I fell from 624 ng/ml to 384 ng/ml (P < 0.001). Tumor growth was controlled in two of three nonfunctioning pituitary adenomas, and three of four corticotrope adenomas. There were no adverse effects from SMART. Notably there have been no visual sequelae or further loss of anterior pituitary function in this heavily pretreated group. Our data indicate that SMART is an effective complementary therapy for pituitary adenomas that have displayed a suboptimal response to conventional therapy including external irradiation. PMID:14602770

Swords, F M; Allan, C A; Plowman, P N; Sibtain, A; Evanson, J; Chew, S L; Grossman, A B; Besser, G M; Monson, J P

2003-11-01

296

Pope Benedict XVI and the Jews: a relationship under suspicion?  

Microsoft Academic Search

The article deals with the question of whether the view that Benedict's relationship with the Jews needs to be regarded with suspicion is justified. Ratzinger's respective theology is scrutinized. Special attention is given to the contested Good Friday prayer for Jews as well as to the attempt at re-integrating the priests of the Pius X priest community. It cannot be

Hans Hermann Henrix

2010-01-01

297

Regulators of cell division in plant tissues. XVI  

Microsoft Academic Search

[3H]Zeatin was supplied through the transpiration stream to radish (Raphanus sativus L.) seedlings with roots excised. Formation of dihydrozeatin was not detected but numerous other metabolites were formed, including adenine, adenosine, AMP, zeatin riboside and zeatin riboside-5'-monophosphate. However, in labelled seedlings which had been left in water for 15 h, an unknown compound (raphanatin) was the dominant metabolite and accounted

C. W. Parker; D. S. Letham

1973-01-01

298

Higher Education: Handbook of Theory and Research, Volume XVI.  

ERIC Educational Resources Information Center

|This volume contains essays related to various aspects of higher education, focusing on both educational theory and research. The chapters are: (1) "Apologia pro Vita Mia" (Robert Berdahl); (2) "Varieties of Validity: Quality in Qualitative Research" (Yvonna S. Lincoln); (3) "Academic Freedom and Federal Courts in the 1990s: The Legitimation of…

Smart, John C., Ed.

299

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2013 CFR

...School may participate in interscholastic sports and activities on an informal or formal...other schools in setting up a schedule of sports and games. Schools that participate...interscholastic competition in noncontact sports except on the basis of individual...

2013-04-01

300

Planck early results. XVI. The Planck view of nearby galaxies  

Microsoft Academic Search

The all-sky coverage of the Planck Early Release Compact Source Catalogue (ERCSC) provides an unsurpassed survey of galaxies at submillimetre (submm) wavelengths, representing a major improvement in the numbers of galaxies detected, as well as the range of far-IR\\/submm wavelengths over which they have been observed. We here present the first results on the properties of nearby galaxies using these

P. A. R. Ade; N. Aghanim; M. Arnaud; M. Ashdown; J. Aumont; C. Baccigalupi; A. Balbi; A. J. Banday; R. B. Barreiro; J. G. Bartlett; E. Battaner; K. Benabed; A. Benoît; J.-P. Bernard; M. Bersanelli; R. Bhatia; J. J. Bock; A. Bonaldi; J. R. Bond; J. Borrill; M. Bucher; C. Burigana; P. Cabella; J.-F. Cardoso; A. Catalano; L. Cayón; A. Challinor; A. Chamballu; R.-R. Chary; L.-Y. Chiang; P. R. Christensen; D. L. Clements; S. Colombi; F. Couchot; A. Coulais; B. P. Crill; F. Cuttaia; L. Danese; R. D. Davies; R. J. Davis; P. de Bernardis; G. de Gasperis; A. de Rosa; G. de Zotti; J. Delabrouille; J.-M. Delouis; F.-X. Désert; C. Dickinson; H. Dole; S. Donzelli; O. Doré; U. Dörl; M. Douspis; X. Dupac; G. Efstathiou; T. A. Enßlin; F. Finelli; O. Forni; M. Frailis; E. Franceschi; S. Galeotta; K. Ganga; M. Giard; G. Giardino; Y. Giraud-Héraud; J. González-Nuevo; K. M. Górski; S. Gratton; A. Gregorio; A. Gruppuso; F. K. Hansen; D. Harrison; G. Helou; S. Henrot-Versillé; D. Herranz; S. R. Hildebrandt; E. Hivon; M. Hobson; W. A. Holmes; W. Hovest; R. J. Hoyland; K. M. Huffenberger; A. H. Jaffe; W. C. Jones; M. Juvela; E. Keihänen; R. Keskitalo; T. S. Kisner; R. Kneissl; L. Knox; H. Kurki-Suonio; G. Lagache; A. Lähteenmäki; J.-M. Lamarre; A. Lasenby; R. J. Laureijs; C. R. Lawrence; S. Leach; R. Leonardi; M. Linden-Vørnle; M. López-Caniego; P. M. Lubin; J. F. Macías-Pérez; C. J. MacTavish; S. Madden; B. Maffei; D. Maino; N. Mandolesi; R. Mann; M. Maris; E. Martínez-González; S. Masi; S. Matarrese; F. Matthai; P. Mazzotta; A. Melchiorri; L. Mendes; A. Mennella; M.-A. Miville-Deschênes; A. Moneti; L. Montier; G. Morgante; D. Mortlock; D. Munshi; A. Murphy; P. Naselsky; P. Natoli; C. B. Netterfield; H. U. Nørgaard-Nielsen; F. Noviello; D. Novikov; I. Novikov; S. Osborne; F. Pajot; B. Partridge; F. Pasian; G. Patanchon; M. Peel; O. Perdereau; L. Perotto; F. Perrotta; F. Piacentini; M. Piat; S. Plaszczynski; E. Pointecouteau; G. Polenta; N. Ponthieu; T. Poutanen; G. Prézeau; S. Prunet; J.-L. Puget; W. T. Reach; R. Rebolo; M. Reinecke; C. Renault; S. Ricciardi; T. Riller; I. Ristorcelli; G. Rocha; C. Rosset; M. Rowan-Robinson; J. A. Rubiño-Martín; B. Rusholme; M. Sandri; G. Savini; D. Scott; M. D. Seiffert; P. Shellard; G. F. Smoot; J.-L. Starck; F. Stivoli; V. Stolyarov; R. Sudiwala; J.-F. Sygnet; J. A. Tauber; L. Terenzi; L. Toffolatti; M. Tomasi; J.-P. Torre; M. Tristram; J. Tuovinen; M. Türler; G. Umana; L. Valenziano; J. Varis; P. Vielva; F. Villa; N. Vittorio; L. A. Wade; B. D. Wandelt; D. Yvon; A. Zacchei; A. Zonca

2011-01-01

301

Climate determinism or Geomagnetic determinism?  

NASA Astrophysics Data System (ADS)

A number of episodes of sharp geomagnetic field variations (in both intensity and direction), lasting on the order of a century, have been identified in archeomagnetic records from Western Eurasia and have been called "archeomagnetic jerks". These seem to correlate well with multi-decadal cooling episodes detected in the North Atlantic Ocean and Western Europe, suggesting a causal link between both phenomena. A possible mechanism could be a geomagnetic modulation of the cosmic ray flux that would control the nucleation rate of clouds. We wish to underline the remarkable coincidence between archeomagnetic jerks, cooling events in Western Europe and drought periods in tropical and sub-tropical regions of the northern hemisphere. The latter two can be interpreted in terms of global teleconnections among regional climates. It has been suggested that these climatic variations had caused major changes in the history of ancient civilizations, such as in Mesopotamia, which were critically dependent on water supply and particularly vulnerable to lower rainfall amounts. This is one of the foundations of "climate determinism". Our studies, which suggest a geomagnetic origin for at least some of the inferred climatic events, lead us to propose the idea of a "geomagnetic determinism" in the history of humanity.

Gallet, Y.; Genevey, A.; Le Goff, M.; Fluteau, F.; Courtillot, V.

2006-12-01

302

A microcalorimetric sensor for food and cosmetic analyses: l-Malic acid determination.  

PubMed

Enzymatic microcalorimetry has been successfully employed in the reliable determination of the l-malic acid concentration in some foods and cosmetic products. The l-malic acid concentration during the wine-making process is particularly useful in order to control the progress of the malo-lactic fermentation. Total acidity, taste and flavour characteristics of wine depend on the l-malic acid quantity still present. To point out the analytical methodology the dehydration process of l-malic acid, in the presence of Fumarase enzyme, has been used. The new method has been compared with a common spectrophotometric one. By the proposed calorimetric method the l-malic acid concentration in different types of food (white and red wines, fruits and soft beverages) has been determined. In some cosmetic products too the l-malic acid was quantified. The method outlined resulted simple, direct and reliable (good accuracy and precision), in particular it does not require any pre-treatment or clean up of the samples, save the dilution in buffer. PMID:18371803

Antonelli, Marta Letizia; Spadaro, Claudio; Tornelli, Rosalia Fortunata

2007-10-02

303

Experimental determination of the third derivative of G. I. Enthalpic interaction  

NASA Astrophysics Data System (ADS)

The solute (i)-solute interaction in terms of enthalpy, Hi-iE=N(?2HE/?ni2)=(1-xi)(?2HE/?ni?xi), the third derivative of G, was experimentally determined using a Thermal Activity Monitor isothermal titration calorimeter for aqueous solutions of 2-butoxyethanol (BE) and 1-propanol (1P). This was done using both calorimetric reference and sample vessels actively. We simultaneously titrate small and exactly equal amounts of solute i (=BE or 1P) into both cells which contain the binary mixtures at an average mole fraction, xi, which differs by a small amount ?xi. The appropriate amount of titrant ?ni was chosen so that the quotient (?HE/?ni) can be approximated as (?HE/?ni), and so that the scatter of the results is reasonable. ?HE is the thermal response from an individual cell on titration, and we measure directly the difference in the thermal response between the two cells, ?(?HE). The resulting quotient, ?(?HE)/?ni/?xi, can be approximated as (?2HE/?ni?xi) and hence provides a direct experimental avenue for the enthalpy interaction function. We varied the value of ?xi to seek its appropriate size. Since HE contains the first derivative of G with respect to T, the result is the third derivative quantity. Thus we present here a third derivative quantity directly determined experimentally for the first time.

Westh, Peter; Inaba, Akira; Koga, Yoshikata

2008-12-01

304

20 CFR 641.510 - What types of income are included and excluded for participant eligibility determinations?  

Code of Federal Regulations, 2012 CFR

...unemployment compensation, a benefit received under title XVI of...payment made to or on behalf of veterans or former members of the Armed...administered by the Secretary of Veterans Affairs, or 25 percent of a benefit received under title II...

2012-04-01

305

Thermal and Physical Property Determinations for Ionsiv IE-911 Crystalline Silicotitanate and Savannah River Site Waste Simulant Solutions  

SciTech Connect

This document describes physical and thermophysical property determinations that were made in order to resolve questions associated with the decontamination of Savannah River Site (SRS) waste streams using ion exchange on crystalline silicotitanate (CST). The research will aid in the understanding of potential issues associated with cooling of feed streams within SRS waste treatment processes. Toward this end, the thermophysical properties of engineered CST, manufactured under the trade name, Ionsive{reg_sign} IE-911 by UOP, Mobile, AL, were determined. The heating profiles of CST samples from several manufacturers' production runs were observed using differential scanning calorimetric (DSC) measurements. DSC data were obtained over the region of 10 to 215 C to check for the possibility of a phase transition or any other enthalpic event in that temperature region. Finally, the heat capacity, thermal conductivity, density, viscosity, and salting-out point were determined for SRS waste simulants designated as Average, High NO{sub 3}{sup {minus}} and High OH{sup {minus}} simulants.

Bostick, D.T.; Steele, W.V.

1999-08-01

306

Number of free hydroxyl groups on bile Acid phospholipids determines the fluidity and hydration of model membranes.  

PubMed

Interactions of synthetic phospholipids with model membranes determines the drug release capabilities of phospholipid vesicles at diseased sites. We performed 1,6-diphenyl-1,3,5-hexatriene (DPH)-based fluorescence anisotropy, Laurdan-based membrane hydration, and differential scanning calorimetry (DSC) studies to cognize the interactions of three bile acid phospholipids, lithocholic acid-phosphocholine (LCA-PC), deoxycholic acid-phosphocholine (DCA-PC), and cholic acid-phosphocholine (CA-PC) with model membranes. These studies revealed that bile acid phospholipids increases membrane fluidity in DCA-PC > CA-PC > LCA-PC order, indicating that induction of membrane fluidity is contingent on the number and positioning of free hydroxyl groups on bile acids. Similarly, DCA-PC causes maximum membrane perturbations due to the presence of a free hydroxyl group, whereas LCA-PC induces gel phase in membranes due to hydrophobic bile acid acyl chain interactions. These DCA-PC-induced membrane perturbations induce a drastic decrease in phase transition temperature (Tm) as determined by calorimetric studies, whereas doping of LCA-PC causes phase transition broadening without change in Tm. Doping of CA-PC induces membrane perturbations and membrane hydration like DCA-PC but sharpening of phase transition at higher doping suggests self-association of CA-PC molecules. Therefore these differential mode of interactions between bile acid phospholipids and model membranes would help in the future for their use in drug delivery. PMID:24079709

Sreekanth, Vedagopuram; Bajaj, Avinash

2013-09-30

307

DIPPER project 871 determination of ideal-gas enthalpies of formation for key compounds, The 1991 project results  

SciTech Connect

Results of a study aimed at improving group-contribution methodology for estimating thermodynamic properties of organic substances are reported. Specific weaknesses where particular group-contribution terms were unknown, or estimated because of lack of experimental data, are addressed by experimental studies of enthalpies of combustion in condensed phase, vapor-pressure measurements, and differential scanning calorimetric (d.s.c.) heat-capacity measurements. Ideal-gas enthalpies of formation of cyclohexene, phthalan (2,5-dihydrobenzo-3,4-furan), isoxazole, n-octylamine, di-n-octylamine, tri-n-octylamine, phenyl isocyanate, and 1,4,5,6-tetrahydropyrimidine are reported. Two-phase (liquid + vapor) heat capacities were determined for phthalan, isoxazole, the three octylamines, and phenyl isocyanate. Liquid-phase densities along the saturation line were measured for phthalan and isoxazole at 298 to 425 K. The critical temperature and critical density of n-octylamine were determined from d.s.c. results and critical pressure derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, pressures, and densities for cyclohexene (pressure and density only), phthalan, isoxazole, di-n-octylamine, and phenyl isocyanate. Group-additivity parameters or ring-correction terms are derived.

Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Tasker, I.R.

1993-09-01

308

Optimized structure and thermochemical properties of flavonoids determined by the CHIH(medium) DFT model chemistry versus experimental techniques  

NASA Astrophysics Data System (ADS)

The purpose of this work was to evaluate the accuracy of the CHIH(medium) DFT model chemistry (PBEg/CBSB2??//PBEg/CBSB4) in the determination of the optimized structure and thermochemical properties of heterocyclic systems of medium size such as flavonoids, wherefore were selected three of the most abundant flavonoids in vegetable tissues, and which posses the higher antioxidant activity: quercetin, (+)-catechin and cyanidin. As reference systems were employed three cyclic compounds: phenol, catechol and resorcinol. The thermochemical properties evaluated were enthalpy of formation, bond dissociation enthalpy (BDE) and ionization potential (IP), following the scheme of isodesmic reactions. The theoretical results were compared with experimental data generated by X-ray diffraction and calorimetric techniques realized in part by us, whereas other data were taken from the literature. The results obtained in this work reveal that the CHIH(medium) DFT model chemistry represents an accurate computational tool to calculate structural and thermochemical properties in the studied flavonoid and reference compounds. The average absolute deviation of enthalpy of formation for reference compounds was 3.0 kcal/mol, 2.64 kcal/mol for BDE, and 2.97 kcal/mol for IP.

Mendoza-Wilson, Ana MaríA.; Lardizabal-Gutiérrez, Daniel; Torres-Moye, Enrique; Fuentes-Cobas, Luis; Balandrán-Quintana, René R.; Camacho-Dávila, Alejandro; Quintero-Ramos, Armando; Glossman-Mitnik, Daniel

2007-12-01

309

A POTENTIOMETRIC AND CALORIMETRIC STUDY OF THE THERMODYNAMICS OF FORMATION OF SOME OF THE COMPLEXES OF THE d METAL IONS SILVER(I), MERCURY(II), AND CADMIUM(II) WITH THIODIGLYCOL, THIOUREA, AND THE SULPHITE ION  

Microsoft Academic Search

The standard free energy, enthalpy, and entropy changes of complex formation of the d metal ions Ag(I), Hg(H), and Cd(II) with the S-donor-atom ligands thiodiglycol, thiourea, and sulphite were investigated at 298.15 ± 0.05 K. The free-energy changes ?Gi° were calculated from stability constants ?i, which were determined by silver- and mercury-electrode potentiometry, if suitable literature data were not available.

Fabrizio Marsicano; Robert D. Hancock

1976-01-01

310

High-pressure high-temperature stability of ?PbO2-type TiO2 and MgSiO3 majorite: Calorimetric and in situ X-ray diffraction studies  

NASA Astrophysics Data System (ADS)

The rutile-?PbO2 transition in TiO2 has been examined by in situ x-ray diffraction experiments in the pressure range of 4.6-8.5 GPa at temperatures of 500-900°C. Relative change of the two phases with time was observed to determine the equilibrium phase boundary. The determined boundary, P(GPa) = 3.5 + 3.8 × 10-3 T(°C), is quite different from that obtained from synthesis experiments by Dachille et al. By hydrostatic compression experiments of ?PbO2-type TiO2 at pressures to 6 GPa at room temperature, the zero-pressure bulk modulus was determined to be 253 ± 4 GPa, assuming the pressure derivative of 4. Enthalpies of solution of MgSiO3 pyroxene and garnet (majorite) were measured by high temperature solution calorimetry, resulting in the pyroxene-garnet transition enthalpy of 30.80 ± 3.11 kJ/mol at 710°C. Using the present data with the previous thermodynamic data, phase relations in MgSiO3 among pyroxene, garnet, ? (or ?)-Mg2SiO4 plus stishovite, ilmenite, and perovskite have been thermodynamically calculated. The calculated boundaries are generally consistent with the high pressure experimental data. For the pyroxene-garnet and garnet-perovskite transitions, the calculated P-T slopes have small negative and positive values, respectively.

Akaogi, Masaki; Kusaba, Keiji; Susaki, Jun-ichi; Yagi, Takehiko; Matsui, Masanori; Kikegawa, Takumi; Yusa, Hitoshi; Ito, Eiji

311

Phase equilibrium and calorimetric study of the transition of MnTiO 3 from the ilmenite to the lithium niobate structure and implications for the stability field of perovskite  

Microsoft Academic Search

The phase boundary between MnTiO3 I (ilmenite structure) and MnTiO3 II (lithium niobate structure) has been determined by analysis of quench products from reversal experiments in a cubic anvil\\u000a apparatus at 1073–1673 K and 43–75 kbar using mixtures of MnTiO3 I and II as starting materials. Tight brackets of the boundary give P(kbar)=121.2?0.045 T(K). Thermodynamic analysis of this boundary gives

Jaidong Ko; Nancy E. Brown; Alexandra Navrotsky; Charles T. Prewitt; Tibor Gasparik

1989-01-01

312

Core lipid structure is a major determinant of the oxidative resistance of low density lipoprotein.  

PubMed Central

The influence of thermally induced changes in the lipid core structure on the oxidative resistance of discrete, homogeneous low density lipoprotein (LDL) subspecies (d, 1.0297-1.0327 and 1.0327-1.0358 g/ml) has been evaluated. The thermotropic transition of the LDL lipid core at temperatures between 15 degrees C and 37 degrees C, determined by differential scanning calorimetry, exerted significant effects on the kinetics of copper-mediated LDL oxidation expressed in terms of intrinsic antioxidant efficiency (lag time) and diene production rate. Thus, the temperature coefficients of oxidative resistance and maximum oxidation rate showed break points at the core transition temperature. Temperature-induced changes in copper binding were excluded as the molecular basis of such effects, as the saturation of LDL with copper was identical below and above the core transition. At temperatures below the transition, the elevation in lag time indicated a greater resistance to oxidation, reflecting a higher degree of antioxidant protection. This effect can be explained by higher motional constraints and local antioxidant concentrations, the latter resulting from the freezing out of antioxidants from crystalline domains of cholesteryl esters and triglycerides. Below the transition temperature, the conjugated diene production rate was decreased, a finding that correlated positively with the average size of the cooperative units of neutral lipids estimated from the calorimetric transition width. The reduced accessibility and structural hindrance in the cluster organization of the core lipids therefore inhibits peroxidation. Our findings provide evidence for a distinct effect of the dynamic state of the core lipids on the oxidative susceptibility of LDL and are therefore relevant to the atherogenicity of these cholesterol-rich particles.

Schuster, B; Prassl, R; Nigon, F; Chapman, M J; Laggner, P

1995-01-01

313

Determinate Sentencing in California.  

National Technical Information Service (NTIS)

A report on California's Uniform Determinate Sentencing Act is reported to apprise state officials of its intent and results to date. Determinate sentencing was adopted because of the state's skyrocketing crime rate coupled with the abuse of indeterminate...

D. Howard

1978-01-01

314

An in vitro method for the quantitative determination of the antimicrobial efficacy of silver-containing wound dressings.  

PubMed

Treatment with silver-containing wound dressings is becoming an increasingly popular strategy to eliminate growth of opportunistic wound pathogens during the healing process. However, there are concerns over the possible side-effects of silver to the patient; coupled to the cost of silver as an ingredient there is a desire to ensure that wound dressings contain the least quantity of active ingredient to ensure the minimum bactericidal concentration (MBC) of silver is maintained in the wound environment. This requires the ability to determine the efficacy of silver directly within the wound environment; an extremely complicated task that is difficult using classical (plate counting) microbiological assays because these cannot be conducted in situ. Here, we report a quantitative method for determining the efficacy of silver in wound dressings using an isothermal calorimetric method. The growth curves of P. aeruginosa (NCIMB 8628) were recorded in growth medium and in growth medium containing AQUACEL Ag Hydrofiber dressing. It was found that 10 mg of dressing was sufficient to ensure no detectable growth of organism in 2.5 mL of medium inoculated to 10(6) cfu/mL. This corresponded to a silver load of 1.1x10(-6) moles (equivalent to 4.4x10(-4) M, in the volume of medium used in the experiment). Experiments conducted with silver nitrate rather than dressing indicated the MBC of silver against P. aeruginosa was 1x10(-4) M. The results suggested that not all of the silver in the dressing was bioavailable, at least over the lifetime of the experiment. One advantage of this effect would be the lack of excess availability of the silver, which allays fears of potential toxicity to the patient and may provide an extended period of time over which the dressing is bactericidal. PMID:18832021

Gaisford, Simon; Beezer, Anthony E; Bishop, Alistair H; Walker, Michael; Parsons, David

2008-09-11

315

Robust computation of determinant  

NASA Astrophysics Data System (ADS)

This paper is concerned with the numerical computation of the determinant of a matrix. An algorithm for accurately computing the determinant is proposed using accurate matrix factorizations, especially extremely ill-conditioned cases are treated. For the purpose, an accurate algorithm for the inverse LU factorization is used. Then accurate results of the determinant can efficiently be obtained for much wider range of the problems. Numerical results are also presented showing the performance of the proposed algorithm.

Ogita, Takeshi

2012-12-01

316

The Mayans: Climate Determinism or Geomagnetic Determinism?  

NASA Astrophysics Data System (ADS)

Climatic variations since the end of the last ice age have been large enough to influence the fate of ancient civilizations, and deciphering the exact role of climate in the history of old societies is an active and challenging domain of research. This potential influence, which serves as the foundation of `climate determinism,' can be viewed as the response of natural-resource-dependent, agriculture-based communities to climatically driven environmental changes. In some cases, these could have provoked major damage in economic and social organization of the societies, thus paving the way for political disintegration.

Gallet, Yves; Genevey, Agnès

2007-03-01

317

Viking satellite orbit determination  

Microsoft Academic Search

During the summer of 1976, the two Viking spacecraft, each consisting of an orbiter-lander combination, were inserted into orbit about Mars. The paper describes the experiences of the Viking Satellite Orbit Determination Team in determining Mars centered ephemerides of the orbiters and positions of the landers from the two-way Doppler and range data, and synthesizes the different phases of the

C. E. Hildebrand; E. J. Christensen; D. H. Boggs; G. H. Born; H. Hokikian; J. F. Jordan; W. B. Howard

1977-01-01

318

Determinate sentencing in Colorado  

Microsoft Academic Search

In 1980, a study of Colorado's new determinate sentencing law was conducted to discover what changes had occurred. A probability sample of felons convicted before and after the law was selected and comparisons made. Data suggest that no significant change in plea (charge) bargaining practices occurred under determinate sentencing. In addition, no significant differences in commitment rates or lengths of

Herbert C. Covey; Mary Mande

1985-01-01

319

Social Determinants of Health  

Cancer.gov

Social Determinants of Health You will need Adobe Flash Player 8 or later and JavaScript enabled to view this video. You can view the movie here Video of webinar for public health professionals introducing the concept of social determinants of health

320

The thermodynamic characterization of the H-induced amorphization of CeFe{sub 2} and the determination of the energy site distribution using reaction calorimetry  

SciTech Connect

The enthalpy of reaction for the hydrogen-induced amorphization of CeFe{sub 2} has been determined as a function of n = H/CeFe{sub 2}. At 323 K the enthalpy for this amorphization reaction is constant equal to {minus}37 kJ/mol {1/2}H{sub 2} from n = 0 to 1.8; it then declines in magnitude to about {minus}24 kJ/mol {1/2}H{sub 2} at n = 3.0. The hydrogen pressure is too small to measure at 323 K except for n {ge} 2.5. Hydrogen can be partially removed from the amorphized hydride at, e.g., 573 K, permitting the determination of the reaction enthalpy for the reintroduction of the hydrogen into the hypostoichiometric amorphous hydride. Enthalpies could be determined using this technique from about n = 2 to 3. From the relationship between these calorimetrically measured {Delta}H{sub H} values and n for the reintroduction of hydrogen into the hypostoichiometric hydride, i.e., n < 3.0, a part of the energy distribution function for the occupation of the interstices with hydrogen can be determined. The distribution function can be closely described by a Gaussian function with {sigma} = 14 kJ/mol {1/2}H{sub 2} with an average value of {Delta}H{sub H}{sup av} = {minus}54 kJ/mol {1/2}H{sub 2}. If the distribution is indeed a Gaussian, the {Delta}H for the following reaction can be obtained, i.e., CeFe{sub 2}(c) {yields} CeFe{sub 2}(a) {Delta}H(c{yields}a) = 51 kJ/mol CeFe{sub 2}.

Luo, S.; Clewley, J.D.; Flanagan, T.B. [Univ. of Vermont, Burlington, VT (United States)

1996-10-01

321

A Comparison of Multi-Transducer Arrays and Single-Transducer Arrays for the Determination of Multi-Vapor Mixtures  

Microsoft Academic Search

This study provides a comprehensive analysis of multi-transducer (MT) array performance, illustrating quantitatively the advantages of such arrays over their single-transducer (ST) counterparts. Calibrations were performed for 11 vapors with five cantilevers, five capacitive, and five calorimetric sensors coated with five different polymers. Using these data in Monte Carlo simulations coupled with a disjoint principal component regression pattern recognition algorithm

Chunguang Jin; Edward T. Zellers; Petra Kurzawski; Andreas Hierlemann

2007-01-01

322

The Observer Determination  

NASA Astrophysics Data System (ADS)

Quantum measurement requires an observer to prepare a specific measuring device among alternatives where the prepared basis of states, representing the device, is the way the observer interprets quantum reality into his macroscopic word. We redefine that observer role through a new concept: The observer determination, that is, a selection between the measurement options facing the observer. Unlike the measurement itself that is rationalized as dictated by nature, the observer determination can neither be measured nor proven to be true or false. In this paper we propose a mathematical formalism demonstrating how to define the observer determination. Moreover, we present a scheme showing how the apparently subjective observer determination transform into a measurable quantity.

Roth, Yehuda Gavriel

2012-12-01

323

Pole Determination of Asteroids  

NASA Astrophysics Data System (ADS)

By the combined method rotation parameters and shapes of 4 asteroids were determined. The calculation program is developed in MATLAB and shows the 3D shapes of asteroids and their parameters at the same time.

Tungalag, N.; Bayarbat, T.

2012-05-01

324

Determinants of Children's Health.  

National Technical Information Service (NTIS)

The purpose of this research is to investigate empirically the determinants of children's health with particular reference to home and local environmental variables such as family income, parents' schooling, preventive medical care, and health manpower av...

D. Chernichovsky D. Coate L. N. Edwards M. Grossman R. A. Shakotko

1980-01-01

325

Fluoride Determinations in Water.  

National Technical Information Service (NTIS)

The report is a manual for a course designed to provide water fluoride analysis training for individuals directly involved in performing fluoride determinations on drinking waters. The contents include health and engineering aspects of water fluoridation,...

1971-01-01

326

Power Value Determinations. Guidelines.  

National Technical Information Service (NTIS)

Accurate determination of power values is of critical importance to Western in order to assess the present and future impacts of decisions being made today about Western's transmission system and the energy generated and transported on it. The concepts pr...

1986-01-01

327

On Sample Size Determination.  

National Technical Information Service (NTIS)

A frequent request made prior to sampling involves the determination of the appropriate sample size necessary to estimate population characteristics (for example, the arithmetic mean) within a specified accuracy. Although the problem can be simply stated,...

1964-01-01

328

Spectrophotometric Determination of Hydrazine  

Microsoft Academic Search

A simple sensitive and selective method is described for the determination of trace amounts of hydrazine. The method is based on the reduction of nitrate to nitrite. Hydrazine in ammoniacal condition is used as reducing agent with copper(II) as catalyst. The nitrite prepared is determined based on the diazo coupling reaction between p?nitroaniline and N?(1?naphthyl)ethylenediammine dihydrochloride(NEDA). The method obeys Beer's

Mary George; K. S. Nagaraja; N. Balasubramanian

2007-01-01

329

Protein Nitrogen Determination  

NASA Astrophysics Data System (ADS)

The protein content of foods can be determined by numerous methods. The Kjeldahl method and the nitrogen combustion (Dumas) method for protein analysis are based on nitrogen determination. Both methods are official for the purposes of nutrition labeling of foods. While the Kjeldahl method has been used widely for over a hundred years, the recent availability of automated instrumentation for the Dumas method in many cases is replacing use of the Kjeldahl method.

Nielsen, S. Suzanne

330

Calorimetric measurements of optical signals in electrostatic discharge studies  

Microsoft Academic Search

A method based on calorimetry and an instrument are described for the absolute measurement of the energy contained in optical radiation, especially in the optical signatures of electrostatic discharge. The optical emission of a spark gap, comprised of two stainless-steel spheres, was collected by an optical condenser system and focused on the calorimeter sensor. The system was calibrated using a

Zdenek Kucerovsky; William D. Greason; Martin W. Flatley

2002-01-01

331

Calorimetric Study of Several Cuprates with Restricted Dimensionality  

Microsoft Academic Search

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

Masaaki Yamaguchi; Tomoki Furuta; Masayasu Ishikawa

1996-01-01

332

Calorimetric Study of Several Cuprates with Restricted Dimensionality  

NASA Astrophysics Data System (ADS)

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.

Yamaguchi, Masaaki; Furuta, Tomoki; Ishikawa, Masayasu

1996-09-01

333

Reversible Unfolding of ?-Sheets in Membranes: A Calorimetric Study  

PubMed Central

The hexapeptide acetyl-Trp-Leu5 (AcWL5) has the remarkable ability to assemble reversibly and spontaneously into ?-sheets on lipid membranes as a result of monomer partitioning followed by cooperative assembly This system provides a unique opportunity to study the thermodynamics of protein folding in membranes, which we have done using isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC). The results, which may represent the first example of reversible thermal unfolding of peptides in membranes, help to define the contribution of hydrogen bonding to the extreme thermal stability of membrane proteins. ITC revealed that the enthalpy change for partitioning of monomeric, unstructured AcWL5 from water into membranes was zero within experimental error over the temperature range of 5 °C to 75 °C. DSC showed that the ?-sheet aggregates underwent a reversible, endothermic, and very asymmetric thermal transition with a concentration-dependent transition temperature (Tm) in the range of 60 °C to 80 °C. A numerical model of nucleation and growth-dependent assembly of oligomeric ?-sheets, proposed earlier to describe ?-sheet formation in membranes, recreated remarkably well the unusual shape and concentration-dependence of the transition peaks. The enthalpy for thermal unfolding of AcWL5 ?-sheets in the membrane was found to be about 8(±1) kcal mol?1, or about 1.3(±0.2) kcal mol?1 per residue.

Wimley, William C.; White, Stephen H.

2010-01-01

334

Calorimetric and SEM studies of PHB–PET polymeric blends  

Microsoft Academic Search

PHB [poly (3-hydroxybutyrate)], post-consumer soft-drink bottles poly (ethylene terephthalate) PET (herein named PET-R) and\\u000a PHBPET-R (blends of PHB and PET-R in several compositions) samples were evaluated by differential scanning calorimetry (DSC)\\u000a and scanning electronic microscopy (SEM) in order to verify their thermal properties and porosity according to amounts of\\u000a PET-R added the blends. The DSC curve showed that the solvents

D. S. Dias; Marisa S. Crespi; M. Kobelnik; C. A. Ribeiro

2009-01-01

335

Calorimetric study of carbon partitioning from martensite into austenite steel  

SciTech Connect

Quenching and partitioning (Q and P) has been developed as a novel steel heat treatment to produce advanced high-strength microstructures consisting of a martensitic matrix containing significant amounts of retained austenite. Austenite stabilization is hypothesized to result from decarburization of the martensite and transport into the austenite. Differential scanning calorimetry was employed to study Q and P microstructures. Two exothermic events were observed when heating a Q and P sample from room temperature to 600 deg. C. An activation energy suggesting a mechanism controlled by carbon diffusion in bcc iron is obtained for the first peak which is believed to be associated with carbon partitioning. The second peak is believed to be associated with austenite decomposition.

De Moor, Emmanuel [Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, Colorado 80401 (United States); Department of Materials Science and Engineering, Ghent University, Technologiepark 903, B-9052 Zwijnaarde (Belgium); Foejer, Cecilia [ArcelorMittal Research Industry Gent, OCAS NV, ArcelorMittal, J. Kennedylaan 3, B-9060 Zelzate (Belgium); Penning, Jan [Department of Materials Science and Engineering, Ghent University, Technologiepark 903, B-9052 Zwijnaarde (Belgium); Clarke, Amy J. [Materials Science and Technology Division, Los Alamos National Laboratory, Mail Stop G770, Los Alamos, New Mexico 87545 (United States); Speer, John G. [Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, Colorado 80401 (United States)

2010-09-01

336

Thermal Characterization of Li-ion Cells using Calorimetric Techniques.  

National Technical Information Service (NTIS)

The thermal stability of Li-ion cells with intercalating carbon anodes and metal oxide cathodes was measured as a function of state of charge and temperature for two advanced cell chemistries. Cells of the 18650 design with Li(sub x) Ni(sub 0.8) Co(sub 0....

E. P. Roth

2000-01-01

337

Calorimetric Thermometry of Meteoritic Troilite: A Feasibility Study.  

National Technical Information Service (NTIS)

Two solid-state phase transitions in troilite (FeS) can be readily measured by differential scanning calorimetry (DSC) on samples of only a few milligrams. Troilite from the Mundrabilla iron meteorite displays a DSC fingerprint which is distinct from that...

J. H. Allton J. L. Gooding

1993-01-01

338

Calorimetric thermometry of meteoritic troilite: A feasibility study  

NASA Astrophysics Data System (ADS)

Two solid-state phase transitions in troilite (FeS) can be readily measured by differential scanning calorimetry (DSC) on samples of only a few milligrams. Troilite from the Mundrabilla iron meteorite displays a DSC fingerprint which is distinct from that of terrestrial troilite from Del Norte Co., California; their response to subsequent heating also differ significantly. Further work may establish whether troilite thermometry of meteorites is possible using DSC.

Allton, J. H.; Gooding, J. L.

1993-03-01

339

Calorimetric studies of the thermal denaturation of cytochrome c peroxidase  

SciTech Connect

Two endotherms are observed by differential scanning calorimetry during the thermal denaturation of cytochrome c peroxidase at pH 7.0. The transition midpoint temperatures (t/sub m/) were 43.9 +- 1.4 and 63.3 +- 1.6 /sup 0/C, independent of concentration. The two endotherms were observed at all pH values between 4 and 8, with the transition temperatures varying with pH. Precipitation was observed between pH 4 and 6, and only qualitative data are presented for this region. The thermal unfolding of cytochrome c peroxidase was sensitive to the presence and ligation state of the heme. Only a single endotherm was observed for the unfolding of the apoprotein, and this transition was similar to the high-temperature transition in the holoenzyme. Addition of KCN to the holoenzyme increases the midpoint of the high-temperature transition whereas the low-temperature transition was increased upon addition of KF. Binding of the natural substrate ferricytochrome c to the enzyme increases the low-temperature transition by 4.8 +- 1.3 /sup 0/C but has no effect on the high-temperature transition at pH 7. The presence of cytochrome c peroxidase decreases the stability of cytochrome c, and both proteins appear to unfold simultaneously. The results are discussed in terms of the two domains evident in the X-ray crystallographic structure of cytochrome c peroxidase

Kresheck, G.C.; Erman, J.E.

1988-04-05

340

Calorimetric characterization of membrane materials based on polyvinyl alcohol  

Microsoft Academic Search

There is ample scope for modification of polyvinyl alcohol (PVA) to derive diverse range of properties because of the presence\\u000a of hydroxyl group in its chain. In the present work, PVA has been modified to carboxymethylated polyvinyl alcohol (CPVA) —\\u000a a carboxy-functionalized membrane material. Generally the cohesive energy density has incremental influence on the melting\\u000a point and mechanical strength of

G. S. Mukherjee

2009-01-01

341

Absolute calorimetric calibration of low energy brachytherapy sources  

Microsoft Academic Search

In the past decade there has been a dramatic increase in the use of permanent radioactive source implants in the treatment of prostate cancer. A small radioactive source encapsulated in a titanium shell is used in this type of treatment. The radioisotopes used are generally 125I or 103Pd. Both of these isotopes have relatively short half-lives, 59.4 days and 16.99

Kurt E. Stump

2005-01-01

342

Thermal characterization of Li-ion cells using calorimetric techniques  

SciTech Connect

The thermal stability of Li-ion cells with intercalating carbon anodes and metal oxide cathodes was measured as a function of state of charge and temperature for two advanced cell chemistries. Cells of the 18650 design with Li{sub x}CoO{sub 2} cathodes (commercial Sony cells) and Li{sub x}Ni{sub 0.8}Co{sub 0.2}O{sub 2} cathodes were measured for thermal reactivity. Accelerating rate calorimetry (ARC) was used to measure cell thermal runaway as a function of state of charge (SOC), microcalorimetry was used to measure the time dependence of thermal output, and differential scanning calorimetry (DSC) was used to study the thermal reactivity of the individual components. Thermal decomposition of the anode solid electrolyte interphase (SEI) layer occurred at low temperatures and contributes to the initiation of thermal runaway. Low temperature reactions from 40 C--70 C were observed during the ARC runs that were SOC dependent. These reactions measured in the microcalorimeter decayed over time with power-law dependence and were highly sensitive to SOC and temperature. ARC runs of aged and cycled cells showed complete absence of these low-temperature reactions but showed abrupt exothermic spikes between 105--135 C. These results suggest that during aging the anode SEI layer is decomposing from a metastable state to a stable composition that is breaking down at elevated temperatures.

ROTH,EMANUEL P.

2000-05-31

343

Calorimetric studies of the haemoglobin-haptoglobin reaction  

PubMed Central

Haptoglobin binds haemoglobin so firmly that there is practically no dissociation. It would be expected that the heat of the reaction would be relatively large. The development of the microcalorimeter by Benzinger offered the opportunity to measure the heat of reaction. The experiments were carried out in the Beckman 190B Microcalorimeter in two ways: (1) a constant amount of haptoglobin (Kabi; 65mg.) with different amounts of haemoglobin, and (2) a constant amount of haemoglobin (32·5mg.) with different amounts of haptoglobin. The proteins, each in 5ml. of 0·15m-phosphate buffer, pH7·4, were placed in equal-volume calorimeter cells. The heat produced/mg. of haemoglobin was calculated from the slope of the curve for a constant amount of haptoglobin and from the maximum heat for a constant amount of haemoglobin. This heat is about 70kcal./mole at 37°. ?H varies with temperature, being ?70·2 at 37°, ?29·7 at 20° and 7·2 at 4°. From the amount of haptoglobin required to attain maximum heat with 32·5mg. of haemoglobin and the amount of haemoglobin required to attain maximum heat with 65mg. of haptoglobin, it appears that at excess of haptoglobin there is competition between the reactions of 2moles of haptoglobin with 1mole of haemoglobin (or 2 ??-chains) and 1mole of haptoglobin with 1mole of haemoglobin.

Adams, Ernest C.; Weiss, Margaret R.

1969-01-01

344

Calorimetric studies of the in vitro polymerization of brain tubulin.  

PubMed Central

The enthalpy change for chain propagation in the polymerization of bovine tubulin has been studied directly by stopped-flow microcalorimetry at 17 degrees and 25 degrees, and found to be 0 +/- 1 kcal per mol of 6S tubulin dimer at both temperatures. Substantial heat evolution with a half-time of decay of approximately 1 hr was observed w-en tubulin was injected into the calorimeter. This heat was shown to result from contamination of the tublin by small amounts of some material from the crude brain homogenate from which the tubulin was prepared, and to be totally unconnected with microtubule assembly. Model calculations of nucleated polymerization processes reveal that the van't Hoff enthalpy calculated from the temperature dependence of the critical polymerization concentration is a complicated function of the separate enthalpy changes for nucleation and chain propagation. The published values of this quantity for tubulin probably pertain primarily to the nucleation process. It is shown that our observation of a propagation enthalpy change of vanishingly small size is not necessarily inconsistent with the reported van't Hoff enthalpies.

Sutherland, J W; Sturtevant, J M

1976-01-01

345

Calorimetric evolution of the early pozzolanic reaction of natural zeolites  

Microsoft Academic Search

The pozzolanic reaction between natural zeolite tuffs, portlandite and water was investigated over the course of the early\\u000a reaction period up to 3 days. Isothermal conduction calorimetry experiments supplemented by TG\\/DTG and XRD analyses assisted\\u000a in the elucidation of the sequence of reaction processes taking place. The calorimetry experiments clearly showed the dependence\\u000a of the pozzolanic reaction rate and associated heat

R. Snellings; G. Mertens; J. Elsen

2010-01-01

346

Thermal decomposition of hydroxylamine: isoperibolic calorimetric measurements at different conditions.  

PubMed

Thermal decomposition of hydroxylamine, NH2OH, was responsible for two serious accidents. However, its reactive behavior and the synergy of factors affecting its decomposition are not being understood. In this work, the global enthalpy of hydroxylamine decomposition has been measured in the temperature range of 130-150 °C employing isoperibolic calorimetry. Measurements were performed in a metal reactor, employing 30-80 ml solutions containing 1.4-20 g of pure hydroxylamine (2.8-40 g of the supplied reagent). The measurements showed that increased concentration or temperature, results in higher global enthalpies of reaction per unit mass of reactant. At 150 °C, specific enthalpies as high as 8 kJ per gram of hydroxylamine were measured, although in general they were in the range of 3-5 kJ g(-1). The accurate measurement of the generated heat was proven to be a cumbersome task as (a) it is difficult to identify the end of decomposition, which after a fast initial stage, proceeds very slowly, especially at lower temperatures and (b) the environment of gases affects the reaction rate. PMID:23644689

Adamopoulou, Theodora; Papadaki, Maria I; Kounalakis, Manolis; Vazquez-Carreto, Victor; Pineda-Solano, Alba; Wang, Qingsheng; Mannan, M Sam

2013-03-22

347

Calorimetric investigation of structural relaxation of bulk metallic glasses  

NASA Astrophysics Data System (ADS)

Enthalpy and entropy changes on structural relaxation of Mg65Cu25Tb10 glass have been studied after keeping its samples for varying periods of time ta at several temperatures Tas, and after keeping for fixed ta at various Tas. At a fixed Ta, the decrease in the enthalpy and entropy occurred with time according to a non-exponential kinetics. When the sample was kept for the same ta, but at different Tas, the decrease in the enthalpy and entropy showed a peak at a temperature when the sample reached an equilibrium state for that ta. The rate of heat release from the DSC heating scan was analyzed in terms of the model for non-exponential, non-linear enthalpy relaxation. A single set of parameters that fitted the data for un-annealed glass did not fit the data for the highly annealed glass. This is expected in view of the approximations made in the model and the contribution from the Johari-Goldstein (JG) relaxation. It is shown that the distribution of relaxation times leads to memory effect for a glass sample of complex thermal history. This has been investigated by measurement of the enthalpy change on structural relaxation of two bulk metallic glasses, Mg65Cu25Tb10 and Zr46.75Ti8.25Cu7.5Ni10Be27.5 by DSC using two-step annealing temperature procedure. The memory effect was observed as an increase in enthalpy with time and then a decrease.

Aji, Daisman P. B.; Wen, P.; Johari, G. P.

2013-02-01

348

A calorimetric and computational study of aminomethoxybenzoic acids.  

PubMed

The standard (p(0) = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, of five aminomethoxybenzoic acids, at T = 298.15 K, were derived from the standard molar energies of combustion in oxygen, measured by static-bomb combustion calorimetry. Combining these results with literature results of the standard molar enthalpies of sublimation, at T = 298.15 K, the standard molar enthalpies of formation, in the gaseous phase, were derived. Additionally, the enthalpies of formation of the ten possible isomers of aminomethoxybenzoic acid were estimated using accurate Double Hybrid Density Functional Theory (DHDFT) computational methods. The good agreement between the experimental and estimated values of the enthalpies of formation of the five isomers studied experimentally allows us to be confident on the estimated values for the other five isomers. A quantitative evaluation and analysis of the aromatic character of all the studied isomers based on the calculation of Nucleus Independent Chemical Shifts (NICS) was also conducted. PMID:20718458

Almeida, Ana R R P; Matos, M Agostinha R; Morais, Victor M F; Monte, Manuel J S

2010-09-01

349

Laser calorimetric measurement of two-photon absorption  

Microsoft Academic Search

A laser calorimeter has been used to measure two-photon absorption in solids. This new technique provides greater sensitivity than is possible in nonlinear transmission measurements. The two-photon absorption coefficients of CdTe and CdSe at 1.06 ?m using ?16-nsec (FWHM) pulses are 0.13±0.04 and 0.050±0.014 cm\\/MW, respectively.

Michael Bass; Eric W. Van Stryland; A. F. Stewart

1979-01-01

350

Broadband dielectric spectroscopy and calorimetric investigations of D-lyxose.  

PubMed

Using broadband dielectric spectroscopy, we have studied different types of relaxation processes, namely, primary (?), secondary (?), and another sub-T(g) process called ?-process, in the supercooled state of D-lyxose, over a wide frequency (10(-2)-10(9) Hz) and temperature range (120-340 K). In addition, the same sample was analyzed by differential scanning calorimeter. The temperature dependence of the relaxation times as well as the dielectric strength of different processes has been critically examined. It has been observed that the slower secondary relaxation (designated as ?-) process shifts to lower frequencies with increasing applied pressure, but not the faster one. This pressure dependence indicates that the observed slower secondary relaxation (?-) is Johari-Goldstein relaxation process and faster one (?-process) is probably the rotation of hydroxymethyl (-CH(2)OH) side group attached to the sugar ring, that is, of intramolecular origin. PMID:21767829

Singh, Lokendra P; Alegría, A; Colmenero, J

2011-06-30

351

Neutron detection by measuring capture gammas in a calorimetric approach  

Microsoft Academic Search

The neutron capture detector (NCD) is introduced as a novel detection scheme for thermal and epithermal neutrons that could provide large-area neutron counters by using common detector materials and proven technologies. The NCD is based on the fact that neutron captures are usually followed by prompt gamma cascades, where the sum energy of the gammas equals to the total excitation

Guntram Pausch; Claus-Michael Herbach; Yong Kong; Ralf Lentering; Cristina Plettner; Katja Roemer; Falko Scherwinski; Juergen Stein; Paul Schotanus; Thomas Wilpert

2011-01-01

352

Neutron detection by measuring capture gammas in a calorimetric approach  

Microsoft Academic Search

Radiation detector systems for homeland security applications have been usually equipped with 3He tubes to detect the distinguished neutron signature of Special Nuclear Materials (SNMs). The serious shortage of 3He gas, however, recently initiated substantial efforts to develop alternative neutron detectors, particularly for large-area Radiation Portal Monitors (RPMs). Most activities are currently directed to detectors comprising 6Li or 10B —

Claus-Michael Herbach; Guntram Pausch; Achim Kreuels; Yong Kong; Ralf Lentering; Cristina Plettner; Katja Roemer; Falko Scherwinski; Paul Schotanus; Juergen Stein; Nikolai Teofilov; Thomas Wilpert

2010-01-01

353

Calorimetric studies of the elongation of Avena coleoptile segments.  

PubMed

Elongation rate and heat produced by Avena coleoptile segments suspended in sucrose buffer solutions were measured at pH values from 3.5 to 8.5. The caloric efficiency of elongation (CEE) was defined as the ratio of the rate of elongation to the rate of heat production. Elongation and CEE were greatest at intermediate pH values, but heat production (about 1 cal/g.hr) was insensitive to pH within the limits of experimental error (+/-20%). Quantitative agreement was found between the results of previous respiration studies and the rate of heat production in an aerobic atmosphere, which indicates that oxidative metabolism accounts for essentially all energy changes in the cell, so matter flow is a significant component of the bioenergetics of cell function. Indole-3-acetic acid up to 1 mm, produced about a 10-fold increase in elongation rate, a 5-fold increase of the CEE, and a 25% increase in heat production. Above this concentration, sharp drops in both elongation and heat production occurred, without altering the CEE at pH 6.5, but greatly decreasing the CEE at pH 4.5. Elongation and CEE showed marked decreases after 4 hours in an anaerobic atmosphere, but heat production did not exhibit a proportional decrease. These studies indicate that rate of cell elongation in the presence and absence of auxin is not directly proportional to the overall metabolism of the cell. PMID:16659582

Bogie, H E; Kresheck, G C; Harmet, K H

1976-06-01

354

Thermogravimetric and calorimetric studies of water absorbed in polyaniline  

Microsoft Academic Search

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to study the behavior of residual water absorbed by an emeraldine base and a salt of chemically synthesized polyaniline (PANI—EB, PANI-ES). The matrix of PANI is shown to contain water molecules participating in both reversible and irreversible absorption. In its turn, the reversibly absorbed water consists of two components. The

E. S. Matveeva; R. Diaz Calleja; V. P. Parkhutik

1995-01-01

355

Determining Glassware Accuracy  

NSDL National Science Digital Library

The North Carolina Community College System BioNetwork's interactive eLearning tools (IETs) are reusable chunks of training that can be deployed in a variety of courses or training programs. IETs are designed to enhance, not replace hands-on training. Learners are able to enter a hands-on lab experience better prepared and more confident. This particular IET delves into determining glassware accuracy in the lab. Accompanied by a video, this interactive module walks students through determining the most accurate piece of glassware by calculating the standard deviation and percent of error for each.

2011-11-28

356

A robust method for determining the absorbed dose to water in a phantom for low-energy photon radiation  

NASA Astrophysics Data System (ADS)

The application of more and more low-energy photon radiation in brachytherapy—either in the form of low-dose-rate radioactive seeds such as Pd-103 or I-125 or in the form of miniature x-ray tubes—has induced greater interest in determining the absorbed dose to water in water in this energy range. As it seems to be hardly feasible to measure the absorbed dose with calorimetric methods in this low energy range, ionometric methods are the preferred choice. However, the determination of the absorbed dose to water in water by ionometric methods is difficult in this energy range. With decreasing energy, the relative uncertainty of the photon cross sections increases and as the mass energy transfer coefficients show a steep gradient, the spectra of the radiation field must be known precisely. In this work two ionometric methods to determine the absorbed dose to water are evaluated with respect to their sensitivity to the uncertainties of the spectra and of the atomic database. The first is the measurement of the air kerma free in air and the application of an MC-based conversion factor to the absorbed dose to water. The second is the determination of the absorbed dose to water by means of an extrapolation chamber as an integral part of a phantom. In the complementing MC-calculations, two assortments of spectra each of which is based on a separate unfolding procedure were used as well as two kinds of databases: the standard PEGS and the recently implemented NIST database of EGSnrc. Experimental results were obtained by using a parallel-plate graphite extrapolation chamber and a free-air chamber. In the case when the water kerma in a phantom is determined from the measurements of air kerma free in air, differences in the order of 10% were found, according to which the database or the kind of spectrum is used. In contrast to this, for the second method, the differences found were about 0.5%.

Schneider, T.

2011-06-01

357

Apollo 17 Age Determinations  

Microsoft Academic Search

THE Apollo 17 mission landed in a valley in the highland region forming part of the south-eastern rim of the Sea of Serenity (20° 09' 50'' N, 30° 44' 58'' E). An early allocation of a limited number of samples has been made to provide preliminary information on this site and we report here the results of age determinations we

G. Turner; P. H. Cadogan; C. J. Yonge

1973-01-01

358

Exchange-Rate Determination  

Microsoft Academic Search

This volume is intended to provide a survey of thought about exchange-rate determination as it emerged in the decade of the 1970s. This survey differs from many, however, in that the field itself is in a state of rapid change. Understanding the changes and the reasons for them is therefore essential if the reader is to have a basis for

Anne O. Krueger

359

Determinants of Direct Democracy  

Microsoft Academic Search

This paper investigates on the demographic, economic, political and cultural determinants of direct democracy in 87 countries using an index of direct democracy. The test is interesting since there are important variations across these countries in the referendum and initiative use. We apply a number of estimation techniques. We find that per capita income, education and a larger share of

Nadia Fiorino; Roberto Ricciuti

2007-01-01

360

Determinants of supplement usage  

Microsoft Academic Search

Background: As the use of supplements is growing, this study examines the determinants of vitamin and herbal supplement usage. Instead of treating these as all-encompassing categories, they are broken into specific vitamins and herbs and compared to see if users are different. A measure of frequency of vitamin use is also created.Methods: Logistic and ordinal logistic regressions are run on

Dana Fennell

2004-01-01

361

Ulnar Variance Determination  

Microsoft Academic Search

Surgical procedures concerning the distal articular surfaces of the radius and ulna, demand an accurate method of measurement of ulnar variance. A new method, which is a modification of the method described by Palmer (1982), is introduced.100 randomly selected healthy persons were submitted to X-ray of the wrist and the ulnar variance was determined independently by three observers using both

S. S. KRISTENSEN; E. THOMASSEN; F. CHRISTENSEN

1986-01-01

362

Diazepam disposition determinants  

Microsoft Academic Search

Factors influencing diazepam kinetics were assessed in 4 equal groups (n = 11) of young male and female (aged 21 to 37 yr) and elderly male and female (aged 61 to 84 yr) subjects, all of whom were healthy. In all 44, plasma diazepam concentrations were determined by electron-capture gas-liquid chromatography in multiple samples drawn for as long as 9

David J Greenblatt; Marcia Divoll Allen; Jerold S Harmatz; Richard I Shader

1980-01-01

363

Determining Haugh Units  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rapidly determining shell egg quality in an objective manner is not an easy task. Candling is most often utilized as a quick method for assessing egg quality in a non-destructive manner, but it is a highly subjective method. As you have experienced this week, it is almost impossible for multiple p...

364

Collapse of Determinism  

Microsoft Academic Search

MANY readers of Nature will have noted with interest Prof. H. T. H. Piaggio's clear and dispassionate article on the ``Collapse of Determinism''1. Of particular interest is the statement, ``But a third interpretation goes so far as to claim that the existence of causality is disproved'' . This, of course, was the theme of Prof. E. T. Whittaker's Guthrie Lecture2.

Gilbert D. West

1944-01-01

365

Determination of DTL configurations  

SciTech Connect

A computer code (DLT) has been developed for quickly designing and evaluating different drift-tube linac (DLC) configurations. Inputs to the code include the power losses on reference DTL components determined previously by a computer code such as SUPERFISH. The scaling parameters for the new DTL configuration are beta (particle velocity), accelerating gradient, synchronous phase angle, transit-time factor, and the number of cells per DTL tank. Resulting calculations determine cell size, rf power losses, beam energy, and DTL length of the new configuration. A complete new configuration can be generated in a few seconds on an Apple II computer. Accuracy of this code is within 1% of the more sophisticated code PARMILA.

Tennant, R.A.; Schneider, J.D.

1985-01-01

366

Projectile entry angle determination.  

PubMed

Small angles of projectile entry are difficult to determine in two-dimensional targets or in three-dimensional targets where internal deflection has taken place. This results from the fact that small errors in measurement lead to large errors in the calculation of the sine function used in the estimation of the angular projection of a circle onto an inclined plane at angles of less than 20 degrees from the normal. The use of a bullet tip scale, constructed to the dimensions of the entering projectile, allows a significantly more accurate determination of small angles of entry in targets not subject to stretching. A comparison of the relative error inherent in calculating entry angle using the sine function and measuring the angle using the bullet tip scale demonstrates the suitability of using the tip scale at angles less than 20 degrees and the sine function at entry angles greater than 20 degrees. PMID:3944581

Cashman, P J

1986-01-01

367

Radio determination satellite service  

NASA Astrophysics Data System (ADS)

The capabilities and measured performance of a geosynchronous satellite-based service called the radio determination satellite service (RDSS), which operates at radio frequencies allocated by the International Telecommunications Union (ITU) and is licensed in the United States by the Federal Communications Commission (FCC), are discussed. Plans for both improvement in capability and expansion to nearly global coverage are described. Since RDSS can also provide radio navigation, some comparisons of this service with the Global Positioning System (GPS) are made.

Briskman, Robert D.

1990-07-01

368

Critical line length determination  

Microsoft Academic Search

One of the most severe faults for a circuit breaker to interrupt is the short-line fault (SLF). In this paper, digital testing is applied to determine the critical line length, i.e. the short-line fault percentage that stresses the circuit breaker most, for three different circuit breakers. Three arc models have been used for the calculations and three indicators have been

P. H. Schavemaker; L. van der Sluis; A. J. P. de Lange

2000-01-01

369

Determination of Moisture Content  

NASA Astrophysics Data System (ADS)

The moisture (or total solids) content of foods is important to food manufacturers for a variety of reasons. Moisture is an important factor in food quality, preservation, and resistance to deterioration. Determination of moisture content also is necessary to calculate the content of other food constituents on a uniform basis (i.e., dry weight basis). The dry matter that remains after moisture analysis is commonly referred to as total solids.

Nielsen, S. Suzanne

370

Determination of Epsomite-Hexahydrite Equilibria by the Humidity-Buffer Technique at 0.1 MPa with Implications for Phase Equilibria in the System MgSO4-H2O  

NASA Astrophysics Data System (ADS)

Epsomite (MgSO4.7H2O) and hexahydrite (MgSO4.6H2O) are common minerals found in marine evaporite deposits, in saline lakes as precipitates, in weathering zones of coal and metallic deposits, in some soils and their efflorescences, and possibly on the surface of Europa as evaporite deposits. Thermodynamic properties of these two minerals reported in the literature are in poor agreement. In this study, epsomite-hexahydrite equilibria were determined along four humidity-buffer curves at 0.1 MPa and between 25 and 45°C. Results obtained for the reaction epsomite = hexahydrite + H2O, as demonstrated by very tight reversals along each humidity buffer, can be represented by ln K(+/- 0.012) = 20.001 - 7182.07/T, where K is the equilibrium constant, and T is temperature in Kelvin. The derived standard Gibbs free energy of reaction is 10.13 +/- 0.07 kJ/mol, which is essentially the same value as that calculated from vapor pressure measurements reported in the literature. However, this value is at least 0.8 kJ/mol lower than those calculated from the data derived mostly from calorimetric measurements.

Chou, I.-Ming; Seal, Robert R.

2003-11-01

371

Determination of epsomite-hexahydrite equilibria by the humidity-buffer technique at 0.1 MPa with implications for phase equilibria in the system MgSO4-H2O.  

PubMed

Epsomite (MgSO(4).7H(2)O) and hexahydrite (MgSO(4).6H(2)O) are common minerals found in marine evaporite deposits, in saline lakes as precipitates, in weathering zones of coal and metallic deposits, in some soils and their efflorescences, and possibly on the surface of Europa as evaporite deposits. Thermodynamic properties of these two minerals reported in the literature are in poor agreement. In this study, epsomite-hexahydrite equilibria were determined along four humidity-buffer curves at 0.1 MPa and between 25 and 45 degrees C. Results obtained for the reaction epsomite = hexahydrite + H(2)O, as demonstrated by very tight reversals along each humidity buffer, can be represented by ln K(+/- 0.012) = 20.001 - 7182.07/T, where K is the equilibrium constant, and T is temperature in Kelvin. The derived standard Gibbs free energy of reaction is 10.13 +/- 0.07 kJ/mol, which is essentially the same value as that calculated from vapor pressure measurements reported in the literature. However, this value is at least 0.8 kJ/mol lower than those calculated from the data derived mostly from calorimetric measurements. PMID:14678670

Chou, I-Ming; Seal, Robert R

2003-01-01

372

Determination of epsomite-hexahydrite equilibria by the humidity-buffer technique at 0.1 MPa with implications for phase equilibria in the system MgSO4-H2O.  

USGS Publications Warehouse

Epsomite (MgSO(4).7H(2)O) and hexahydrite (MgSO(4).6H(2)O) are common minerals found in marine evaporite deposits, in saline lakes as precipitates, in weathering zones of coal and metallic deposits, in some soils and their efflorescences, and possibly on the surface of Europa as evaporite deposits. Thermodynamic properties of these two minerals reported in the literature are in poor agreement. In this study, epsomite-hexahydrite equilibria were determined along four humidity-buffer curves at 0.1 MPa and between 25 and 45 degrees C. Results obtained for the reaction epsomite = hexahydrite + H(2)O, as demonstrated by very tight reversals along each humidity buffer, can be represented by ln K(+/- 0.012) = 20.001 - 7182.07/T, where K is the equilibrium constant, and T is temperature in Kelvin. The derived standard Gibbs free energy of reaction is 10.13 +/- 0.07 kJ/mol, which is essentially the same value as that calculated from vapor pressure measurements reported in the literature. However, this value is at least 0.8 kJ/mol lower than those calculated from the data derived mostly from calorimetric measurements.

Chou, I. M.; Seal, 2nd. , R. R.

2003-01-01

373

Determining quality of communication  

US Patent & Trademark Office Database

A method, computer-readable medium, and system for providing a quality measurement based on communications within a communication application. Communication attributes that include information associated with a user's communications are obtained. In embodiments, such communication attributes may pertain to communication duration and communication frequency. Upon obtaining communication attributes, a quality measurement may be determined based on the communication attributes. Such a quality measurement provides an indication of the quality of the user's communications. In embodiments, the quality measurement may be stored, communicated to a user, or implemented within a communication application.

Gollapudi; Sreenivas (Cupertino, CA); Halverson; Alan D. (Sunnyvale, CA); Kenthapadi; Krishnaram G. (Mountain View, CA)

2012-03-20

374

Determination of nonaxisymmetric equilibrium  

SciTech Connect

The Princeton Equilibrium Code is modified to determine the equilibrium surfaces for a large aspect ratio toroidal system with helical magnetic fields. The code may easily be made to include any variety of modes. Verification of the code is made by comparison with an analytic solution for l = 3. Previously observed shifting of the magnetic axis with increasing pressure or with a changed externally applied vertical field is obtained. The case l = 0, a bumpy torus, gives convergence only for the lenient convergence tolerance of epsilon/sub b/ = 1.0 x 10-/sup 2/.

Elkin, D.

1980-01-01

375

Determining steam quality  

US Patent & Trademark Office Database

Method and apparatus for determining the quality of wet steam flowing in a steam line utilizing the relationship between critical flow pressure (P.sub.c) and upstream pressure (P.sub.u) to develop a critical pressure ratio P.sub.c /P.sub.u to obtain the steam water mixture inlet enthalpy (H) from empirical curves and the steam quality from the equation: where H.sub.w =specific enthalphy of water, and H.sub.s =specific enthalpy of steam bath both at P.sub.u.

Muldary; Patrick F. (Walnut Creek, CA); Tansev; Erdal (San Francisco, CA)

1979-04-17

376

Determination of CTX equilibria  

SciTech Connect

The method by which we determine the magnetic field equilibrium for CTX in a nonperturbing manner is presented. Measurements of flux conserver image currents are combined with calculations from a numerical model of the equilibrium. Results give equilibria which differ significantly from the minimum energy state, but the equilibria data are well-described by a model where j/B has a linear dependence on the poloidal flux function. The observation of non-disruptive rotating internal kink distortions (with toroidal mode numbers n = 1, 2 and 3) within the equilibria and theoretical MHD thresholds for the onset of these modes corroborate the inferred equilibria.

Knox, S.O.; Barnes, C.W.; Marklin, G.J.; Jarboe, T.R.; Henins, I.; Hoida, H.W.; Wright, B.L.

1985-01-01

377

Ultratrace determination of curium  

SciTech Connect

Development of a method for detection of curium at near single atom levels is being undertaken as a part of the Advanced Concepts Project at Argonne National Laboratory with funding from the US Department of Energy, Office of Arms Control and Nonproliferation. Ultratrace determination of curium, with the ability to quantify the fraction that is curium-242, provides a signature method of detecting clandestine reprocessing of recently irradiated uranium targets. Curium initially present in any of a variety of materials such as air filters, solid or liquid process waste, soil, flora, or fauna can be recovered via current chemical separations processing techniques. Using the ultratrace method being developed, such recovered curium will be quantified with thousand-fold higher sensitivity than the best currently available method which is alpha counting. This high sensitivity arises because, on average, a given trivalent curium (Cm{sup 3+}) ion can emit a very large number of fluorescence photons before alpha decay occurs.

Beitz, J.V.

1995-02-01

378

Dietary determinants of obesity.  

PubMed

Obesity has become a serious public health problem worldwide, and dietary composition can play a role in its prevention and treatment. However, available literature on the impacts of different dietary factors on weight change is inconsistent, or even conflicting. In this review, we briefly summarized the mechanisms and influences of several major dietary determinants of weight change, with a focus on their potential in the prevention of weight gain or regain. We discussed the intake of fat, protein, total carbohydrates, fruits and vegetables, fibre, free sugars, fructose and sugar sweetened beverages, dietary energy density, portion size, eating outside home, glycaemic index and glycaemic load. Popular weight loss diets, including the Atkins diet, Weight Watchers, Ornish diet and Zone diet, are also briefly discussed for their safety and efficacy in the maintenance of weight loss. PMID:20821929

Du, Huaidong; Feskens, Edith

2010-08-01

379

Determining valve position  

SciTech Connect

A method and apparatus for determining the position of a valve for example ball valves, plug valves, gate valves using a source of radiation such as cesium-137 located either on or adjacent to the external surface of the valve or within the valve itself, for example in the ball of a ball valve, and a radiation detector such as a Geiger-Muller tube on the external surface of the valve. Source and detector are aligned and located relative to one another so that the count rate detected is indicative of the valve position. The method is accurate and, for example, allows the position of the ball in a ball valve to be monitored to within /sub +/ or /sub -/1 mm.

Hurst, J.A.; Jackson, P.

1984-08-28

380

76 FR 56263 - Titles II and XVI: Documenting and Evaluating Disability in Young Adults  

Federal Register 2010, 2011, 2012, 2013

...Evaluating Disability in Young Adults AGENCY: Social Security Administration...Notice of Social Security Ruling (SSR...SUMMARY: In accordance with...benefits was provided in Section 301 of the Social Security Disability...

2011-09-12

381

Chinese-Mandarin: Basic Course. Volume XVI: Lessons 168-180.  

ERIC Educational Resources Information Center

|This is the last of 16 volumes of audiolingual classroom instruction in Mandarin Chinese. The course is designed to train native English speakers to Level 3 Foreign Service Institute proficiency in comprehension and speaking, and to Level 2 proficiency in reading and writing Mandarin. Facility in reading, writing, and translating texts written in…

Defense Language Inst., Monterey, CA.

382

Organometallic Chemistry of the Transition Metals. Xvi. Polynuclear Cyclopentadienylmetal Carbonyls of Iron and Cobalt.  

National Technical Information Service (NTIS)

Prolonged heating of (C5H5Fe(CO)2)2 in boiling xylene solution gives dark green, very stable, crystalline tetrameric (C5H5FeCO)4. Ultraviolet irradiation of C5H5Co(CO)2 in hexane solution gives black, crystalline trimeric (C5H5CoCO)3. Evidence is presente...

R. B. King

1966-01-01

383

RECOMBINATION AND ELECTRON IMPACT EXCITATION RATE COEFFICIENTS FOR S XV AND S XVI  

SciTech Connect

Recombination and electron impact excitation of S{sup 14+} and S{sup 15+} ions was measured at the Stockholm refrigerated electron beam ion trap. The collision energy range was 1.4-3 keV, in which we covered the KLL, KLM, KLN, and KLO dielectronic recombination resonances resulting in S{sup 13+} and S{sup 14+} ions. The recombination rates were obtained by detecting the charge state distribution with a newly developed time-of-flight technique. Resonance energies and cross-sections calculated within the relativistic many-body perturbation theory for S{sup 15+} agree well with the experimental data. The temperature-dependent rate coefficients were extracted from the measured rates and compared with calculations from the literature used for studies of collisionally ionized astrophysical plasmas. Good agreement for S{sup 15+} was obtained, while the plasma rates for S{sup 14+} were 23% lower than the current published values. In addition to the time-of-flight spectra, the X-ray spectra, produced mainly by photo-recombination and excitation, were also collected. The combination of these two measurements allowed us to separate the photo-recombination and the excitation spectra, and the excitation rate coefficients for summed intensities with known fractions of S{sup 14+} and S{sup 15+} ions were extracted.

Mahmood, S.; Ali, S.; Orban, I.; Lindroth, E.; Schuch, R. [Department of Physics, Stockholm University, AlbaNova University Center, S-10691 Stockholm (Sweden); Tashenov, S. [Current address: Physikalisches Institut, Universitaet Heidelberg, D-69120 Heidelberg, Germany. (Germany)

2012-08-01

384

Dynamics of glass-forming liquids. XVI. Observation of ultrastable glass transformation via dielectric spectroscopy  

NASA Astrophysics Data System (ADS)

The transformation of vapor-deposited ultrastable glasses of indomethacin (IMC) into the supercooled liquid state near Tg is monitored by means of dielectric spectroscopy. Films with thickness between 400 and 800 nm are deposited on differential interdigitated electrode cells and their loss profiles are measured during isothermal annealing using a dual-channel impedance technique for frequencies between 0.03 and 100 Hz. All dielectric loss spectra observed during the transformation process can be explained by a volume fraction of the supercooled liquid that increases linearly with time. From the early stages of the transformation to the liquid that is formed via complete annealing of the ultrastable glass, the average dielectric relaxation time as well as the distribution of relaxation times of the liquid component are identical to those of the conventional liquid obtained by cooling the melt. The dependence of the transformation rate on the film thickness is consistent with a growth front mechanism for the direct conversion from the ultrastable glass to the equilibrium supercooled liquid. We conclude that the IMC liquid recovered from the ultrastable glass is structurally and dynamically identical to the conventional supercooled state.

Chen, Z.; Sepúlveda, A.; Ediger, M. D.; Richert, R.

2013-03-01

385

Dynamics of glass-forming liquids. XVI. Observation of ultrastable glass transformation via dielectric spectroscopy.  

PubMed

The transformation of vapor-deposited ultrastable glasses of indomethacin (IMC) into the supercooled liquid state near T(g) is monitored by means of dielectric spectroscopy. Films with thickness between 400 and 800 nm are deposited on differential interdigitated electrode cells and their loss profiles are measured during isothermal annealing using a dual-channel impedance technique for frequencies between 0.03 and 100 Hz. All dielectric loss spectra observed during the transformation process can be explained by a volume fraction of the supercooled liquid that increases linearly with time. From the early stages of the transformation to the liquid that is formed via complete annealing of the ultrastable glass, the average dielectric relaxation time as well as the distribution of relaxation times of the liquid component are identical to those of the conventional liquid obtained by cooling the melt. The dependence of the transformation rate on the film thickness is consistent with a growth front mechanism for the direct conversion from the ultrastable glass to the equilibrium supercooled liquid. We conclude that the IMC liquid recovered from the ultrastable glass is structurally and dynamically identical to the conventional supercooled state. PMID:23556770

Chen, Z; Sepúlveda, A; Ediger, M D; Richert, R

2013-03-28

386

Limits to sustained energy intake. XVI. Body temperature and physical activity of female mice during pregnancy.  

PubMed

Lactation is the most energy-demanding phase of mammalian reproduction, and lactation performance may be affected by events during pregnancy. For example, food intake may be limited in late pregnancy by competition for space in the abdomen between the alimentary tract and fetuses. Hence, females may need to compensate their energy budgets during pregnancy by reducing activity and lowering body temperature. We explored the relationships between energy intake, body mass, body temperature and physical activity throughout pregnancy in the MF1 mouse. Food intake and body mass of 26 females were recorded daily throughout pregnancy. Body temperature and physical activity were monitored every minute for 23 h a day by implanted transmitters. Body temperature and physical activity declined as pregnancy advanced, while energy intake and body mass increased. Compared with a pre-mating baseline period, mice increased energy intake by 56% in late pregnancy. Although body temperature declined as pregnancy progressed, this served mostly to reverse an increase between baseline and early pregnancy. Reduced physical activity may compensate the energy budget of pregnant mice but body temperature changes do not. Over the last 3 days of pregnancy, food intake declined. Individual variation in energy intake in the last phase of pregnancy was positively related to litter size at birth. As there was no association between the increase in body mass and the decline in intake, we suggest the decline was not caused by competition for abdominal space. These data suggest overall reproductive performance is probably not constrained by events during pregnancy. PMID:23720802

Gamo, Yuko; Bernard, Amelie; Mitchell, Sharon E; Hambly, Catherine; Al Jothery, Aqeel; Vaanholt, Lobke M; Król, Elzbieta; Speakman, John R

2013-06-15

387

The Extragalactic Distance Scale Key Project. XVI. Cepheid Variables in an Inner Field of M101  

Microsoft Academic Search

We report on the identification of 255 candidate variable stars in a field located some 1.7' from the center of the late-type spiral galaxy M101 = NGC 5457, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Photometric measurements in the F555W and F814W filters-analyzed independently with the DAOPHOT\\/ALLFRAME and DoPHOT

Peter B. Stetson; Abhijit Saha; Laura Ferrarese; Daya M. Rawson; Holland C. Ford; Wendy L. Freedman; Brad K. Gibson; John A. Graham; Paul Harding; Mingsheng Han; Robert J. Hill; John G. Hoessel; John P. Huchra; Shaun M. G. Hughes; Garth D. Illingworth; Daniel D. Kelson; Robert C. Kennicutt Jr.; Barry F. Madore; Jeremy R. Mould; Randy L. Phelps; Shoko Sakai; Nancy A. Silbermann; Anne Turner

1998-01-01

388

Icosahedral Carboranes. Xvi. Polymerization and Crosslinking Mechanism of Poly-M-Carboranylene-Siloxanes.  

National Technical Information Service (NTIS)

The FeCl3 catalyzed bulk polymerization of a bis-(methoxysilyl)-m-carborane and a dichlorosilane resulting in a poly-m-carboranylenesiloxane raw gum (DEXSIL 200) was found to occur in three distinct parts: First, the low temperature polymerization stage w...

H. J. Dietrich R. P. Alexander T. L. Heying H. Kwasnik C. O. Obenland

1970-01-01

389

Chelation in metal intoxication XVI. Influence of chelating agents on chromate poisoned rats  

SciTech Connect

The ability of selective polyaminocarboxylic acids and common drugs to reduce the body burden of chromium and restore Cr induced biochemical alterations in chromate intoxicated rats was investigated. 1,2 Cychlohexylene dinitrilotetraacetic acid (CDTA) and triethylenetetramine hexacetic acid (TTHA) were more effective than p-aminosalicylic acid (PAS) and isoniazid (INH) in enhancing urinary excretion of Cr, lowering hepatic and blood levels of Cr and restoring inhibited activity of hepatic aldolase. The chromate antidotal property of chelators seem to be related to the combination of nitrogen and oxygen as the electron donating centres.

Tandon, S.K.; Srivastava, L.

1985-01-01

390

Spectra of the Si I isoelectronic sequence from Cu XVI to Mo XXIX  

SciTech Connect

Si-like spectra of Cu to Mo have been observed in tokamak-generated plasmas, and Cu to As in laser-produced plasmas. Wavelengths in the range of 86 to 300 A were recorded photographically with a 2.2-m grazing-incidence spectrograph on the tokamak, and a 10.7-m grazing-incidence spectrograph for the laser plasmas. Wavelength accuracy is estimated to be {plus minus}0.005 A. The transition arrays 3{ital s}23{ital p}{sup 2}--3{ital s}3{ital p}3 and 3{ital s}{sup 2}3{ital p}2--3{ital s}{sup 2}3{ital p}3{ital d} were identified. Classifications were established by comparison with Hartree--Fock calculations of wavelengths and relative intensities along isoelectronic sequences. Spectra of Rb and Sr were not observed, but interpolated values of wavelengths for these ions are derived from the rest of the data. Ground configuration intervals known from magnetic dipole transitions are compared with Dirac--Fock calculations to predict unknown values and to correct misidentifications.

Sugar, J.; Kaufman, V. (National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (USA)) Rowan, W.L. (Fusion Research Center, University of Texas, Austin, Texas 78712 (USA))

1990-02-01

391

American Association of Women in Community and Junior Colleges Quarterly; Vol. XVI, Nos. 1-4.  

ERIC Educational Resources Information Center

|The American Association of Women in Community and Junior Colleges (AAWCJC), an affiliated council of the American Association of Community and Junior Colleges (AACJC), produces the "Quarterly" to disseminate information pertinent to the AAWCJC membership and to provide a forum for the discussion of current issues and events. Each issue of the…

AAWCJC Quarterly, 1992

1992-01-01

392

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XVI, LEARNING ABOUT AC GENERATOR (ALTERNATOR) PRINCIPLES (PART I).  

ERIC Educational Resources Information Center

|THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATING PRINCIPLES OF ALTERNATING CURRENT GENERATORS USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE REVIEWING ELECTRICAL FUNDAMENTALS, AND OPERATING PRINCIPLES OF ALTERNATORS. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL PROGRAMED TRAINING FILM "AC GENERATORS…

Human Engineering Inst., Cleveland, OH.

393

At Issue: Benedict XVI, the Lefebvrians, the Jews, and the State of Israel  

Microsoft Academic Search

This article will explore the relations between the Catholic Church and the Jews from the middle of the previous century until the present day. It will focus on how the Catholic Church has dealt with memory of the Shoah and how this has affected the Church's relations with the Jews. It will look at the most recent developments in dialogue

Sergio I. Minerbi

2009-01-01

394

Alternative Foundations: A Dialogue With Modernity and the Papacy of Benedict XVI  

Microsoft Academic Search

Throughout its history, the institution of the Catholic Church has been at odds with the social and political changes of modernity. However, many scholars claim that after Vatican II, the Church began to accept modernity's political regnancy, and subsequently embraced doctrines such as separation of Church and State and religious freedom. In fact, some scholars go so far as to

Angela C. Miceli

2012-01-01

395

The Synod of Bishops: Provenance of Sacramentum Caritatis of Benedict XVI  

Microsoft Academic Search

The Synod of Bishops is now a regular institution within the formal administrative structures within the Catholic Church. After four decades it is a young veteran. However, it is still not widely appreciated, just as the origins of its main documents are scarcely understood and read by very few. The publication of the Apostolic Post-Synodal Exhortation, just before Easter 2007,

Russell Hardiman

2007-01-01

396

Search for new industrial oils: XVI. Umbelliflorae—seed oils rich in petroselinic acid  

Microsoft Academic Search

Seed oils of the order Umbelliflorae, including those from the families Umbelliferae, Garryaceae, Araliaceae, Cornaceae, Davidiaceae,\\u000a Nyssaceae and Alangiaceae, were analyzed for fatty acid composition by gas liquid chromatography (GLC) of their methyl esters.\\u000a The characteristic fatty acid of the order, petroselinic acid, occurred in the Umbelliferae in amounts up to 85%. In the Araliaceae,\\u000a the content was as high

R. Kleiman; G. F. Spencer

1982-01-01

397

Newsletter for Research in Mental Health and Behavioral Sciences, Volume XVI, Number 1.  

National Technical Information Service (NTIS)

This newsletter is published quarterly and is designed to communicate information among researchers in mental health and the behavioral sciences within the Veterans Administration (VA). Brief reports are presented describing patient problems and the effec...

1974-01-01

398

Benedict XVI on Liberal Modernity's Need for the “Theological Virtues” of Faith, Hope, and Love  

Microsoft Academic Search

A careful reading of Caritas in Veritate shows it to be framed and permeated by two principles. The first is that human persons in their consciences and deeds are the principal agents of economic and political life, whether directly in interpersonal relations or mediated through their work in and for institutions. The second is that human persons as citizens are

Rachel A. Amiri; Mary M. Keys

2012-01-01

399

Follow-Up Study of 1986 Nursing Graduates. Volume XVI, No. 12.  

ERIC Educational Resources Information Center

In spring 1987, a follow-up study of nursing program graduates was conducted at William Rainey Harper College (WRHC) to examine employment patterns, further education plans, and graduates' evaluation of particular aspects of their WRHC experience. Questionnaires were mailed to 112 nursing students who graduated with an associate degree in 1986.…

Dincher, J.; Flaherty, A.

400

Oral histories in meteoritics and planetary science—XVI: Donald D. Bogard  

NASA Astrophysics Data System (ADS)

Donald D. Bogard (Don, Fig. 1) became interested in meteorites after seeing the Fayetteville meteorite in an undergraduate astronomy class at the University of Arkansas. During his graduate studies with Paul Kuroda at Arkansas, Don helped discover the Xe decay products of 244Pu. After a postdoctoral period at Caltech, where he learned much from Jerry Wasserburg, Peter Eberhardt, Don Burnett, and Sam Epstein, Don became one of a number of young Ph.D. scientists hired by NASA's Manned Spacecraft Center to set up the Lunar Receiving Laboratory (LRL) and to perform a preliminary examination of Apollo samples. In collaboration with Oliver Schaeffer (SUNY), Joseph Zähringer (Max Planck, Heidelberg), and Raymond Davis (Brookhaven National Laboratory), he built a gas analysis laboratory at JSC, and the noble gas portion of this laboratory remained operational until he retired in 2010. At NASA, Don worked on the lunar regolith, performed pioneering work on cosmic ray produced noble gas isotopes and Ar-Ar dating, the latter for important insights into the thermal and shock history of meteorites and lunar samples. During this work, he discovered that the trapped gases in SNC meteorites were very similar to those of the Martian atmosphere and thus established their Martian origin. Among Don's many administrative accomplishments are helping to establish the Antarctic meteorite and cosmic dust processing programs at JSC and serving as a NASA-HQ discipline scientist, where he advanced peer review and helped create new programs. Don is a recipient of NASA's Scientific Achievement and Exceptional Service Medals and the Meteoritical Society's Leonard Medal.

Sears, Derek W. G.

2012-03-01

401

Comprehensive Framework Study. California Region. Appendix XVI. Shoreline Protection and Development.  

National Technical Information Service (NTIS)

This appendix concerns itself with needs for protection and development of the shoreline zone. The shoreline zone is considered to include the area subject to erosion from sea action and the closely adjoining landward area and comprises a strip generally ...

1971-01-01

402

Recombination and Electron Impact Excitation Rate Coefficients for S XV and S XVI  

NASA Astrophysics Data System (ADS)

Recombination and electron impact excitation of S14+ and S15+ ions was measured at the Stockholm refrigerated electron beam ion trap. The collision energy range was 1.4-3 keV, in which we covered the KLL, KLM, KLN, and KLO dielectronic recombination resonances resulting in S13+ and S14+ ions. The recombination rates were obtained by detecting the charge state distribution with a newly developed time-of-flight technique. Resonance energies and cross-sections calculated within the relativistic many-body perturbation theory for S15+ agree well with the experimental data. The temperature-dependent rate coefficients were extracted from the measured rates and compared with calculations from the literature used for studies of collisionally ionized astrophysical plasmas. Good agreement for S15+ was obtained, while the plasma rates for S14+ were 23% lower than the current published values. In addition to the time-of-flight spectra, the X-ray spectra, produced mainly by photo-recombination and excitation, were also collected. The combination of these two measurements allowed us to separate the photo-recombination and the excitation spectra, and the excitation rate coefficients for summed intensities with known fractions of S14+ and S15+ ions were extracted.

Mahmood, S.; Ali, S.; Orban, I.; Tashenov, S.; Lindroth, E.; Schuch, R.

2012-08-01

403

Meteorology and Food Production - The Theme of the XVI Meteorology Day.  

National Technical Information Service (NTIS)

In Poland that day was also celebrated very solemnly. It provided an occasion to review our achievements in all areas of meteorology. The importance of meteorology in various fields of economic life was explained to school children, the rural population, ...

M. Molga

1985-01-01

404

Infrared technology XVI; Proceedings of the Meeting, San Diego, CA, July 11-13, 1990  

SciTech Connect

Various papers in infrared technology are presented. Individual topics addressed include: Field Observations and Measurement Experiment, GaAs/AlGAs multiquantum-well IR detectors, 256 x 256 PtSi hybrid array for astronomy applications, compact 128 InSb focal plane assembly for thermal imaging, statistical analysis of thermal images generated by line scanning, performance comparison of platinum silicide cameras, atmospheric applications of IR heterodyne laser detection, French activity in IR astronomy from stratospheric balloons, advances in IR technology at Paris Observatory, far-IR photoconductors, applications of IR bidimensional devices in astronomy, far-IR transmission spectra of YBa2Cu3O(7-d) thin films. Also considered are: far-IR multiple-path cell without internal mirrors, optical properties of solid-state laser-type materials in the near-IR, SOFRADIR IR focal plane array production, recent developments on Isocam long-wavelength channel detector, 128 x 128 3-5 micron focal plane arrays at 77-K and 200-K operation, digital test target for display evaluation, IR radiation from rocket plumes, 128 x 128 InGaAs detector array for 1.0-1.7 micron.

Spiro, I.J. (Aerospace Corp., Los Angeles, CA, (United States))

1990-01-01

405

Diffuse idiopathic skeletal hyperostosis in the Medici, Grand Dukes of Florence (XVI century)  

Microsoft Academic Search

Diffuse idiopathic skeletal hyperostosis (DISH) is a common systemic disorder characterised by the ossification of the anterior\\u000a longitudinal spinal ligament involving at least three contiguous vertebrae and by diffuse extraspinal enthesopathies. The\\u000a condition is associated with the male sex and with advanced age; its aetiology is uncertain, but seems to be related to obesity\\u000a and diabetes. The most recent studies

Valentina Giuffra; Sara Giusiani; Antonio Fornaciari; Natale Villari; Angelica Vitiello; Gino Fornaciari

2010-01-01

406

Perceived Positions Determine Crowding  

PubMed Central

Crowding is a fundamental bottleneck in object recognition. In crowding, an object in the periphery becomes unrecognizable when surrounded by clutter or distractor objects. Crowding depends on the positions of target and distractors, both their eccentricity and their relative spacing. In all previous studies, position has been expressed in terms of retinal position. However, in a number of situations retinal and perceived positions can be dissociated. Does retinal or perceived position determine the magnitude of crowding? Here observers performed an orientation judgment on a target Gabor patch surrounded by distractors that drifted toward or away from the target, causing an illusory motion-induced position shift. Distractors in identical physical positions led to worse performance when they drifted towards the target (appearing closer) versus away from the target (appearing further). This difference in crowding corresponded to the difference in perceived positions. Further, the perceptual mislocalization was necessary for the change in crowding, and both the mislocalization and crowding scaled with drift speed. The results show that crowding occurs after perceived positions have been assigned by the visual system. Crowding does not operate in a purely retinal coordinate system; perceived positions need to be taken into account.

Maus, Gerrit W.; Fischer, Jason; Whitney, David

2011-01-01

407

Nanolabel for TNF-? determination  

NASA Astrophysics Data System (ADS)

Tumor necrosis factor-? (TNF-?), also known as cachectin, is one of the most important regulatory cytokines and mediates a variety of cell functions, including the stimulation of nitric oxide (NO) production which has been related to oxidative stress and diseases such as arthritis, diabetes, stroke, and chronic inflammation. Determination of TNF-? concentration in human serum might be helpful in the staging and prognosis of diseases. And it is also very important for the understanding of tumor biological processes, inherent mechanisms, and discovering drugs as well as having a therapeutic potential for the treatment of diseases. So, in this study, sensor systems based on Reflectometric Interference Spectroscopy (RIfS) have been prepared for selectively recognition and binding of TNF-? biomolecules. For this purpose, photosensitive nano structured TNF-? has been synthesized applying AmiNoAcid (monomer) Decorated and Light Underpining Conjugation Approach (ANADOLUCA) method using bis (2-2'-bipyridyl) MATyr-MATyr-ruthenium(II) (MATyr-Ru-MATyr) as a photosensitive monomer. Then, these photosensitive nano structured TNF-? have been used for TNF-? recognition as an alternative and unique sensor method. Also, the affinity constant of RIfS sensor has been calculated. The method has been showed high sensitivity, good precision and accuracy, and suited for the detection of TNF-? from aqueous solution.

Say, R?dvan; Diltemiz, Sibel Emir; Çelik, Suzan; Ersöz, Arzu

2013-06-01

408

Determining satellite close approaches  

NASA Astrophysics Data System (ADS)

This paper presents a numerical method to evaluate close approaches of two satellites. The algorithm is based on a space curve modeling technique originally developed by Overhauser, presented here as an independent derivation. The method to determine minimum spacing between two space objects is based on creating a relative distance waveform, delta(t), versus time. The waveform is produced from either uniform or arbitrarily spaced data points, from which intervals of close approach are obtained by extracting the real roots of a localized cubic polynomial. This method is free of both transcendental equations and the computation of acceleration terms of the two objects of interest. For this study, a close approach truth table is constructed using a 0.1 second sequential step along the orbits, then differencing the two position vectors. The close approach entrance and exit times for an ellipsoidal quadric surface are then located using a piecewise linear interpolator, and serve as a benchmark for comparison. The simulation results show this algorithm produces encounter times almost identical to those in the truth table, with a 99.84 percent reduction in computer runtime. The results, created from real orbital data, include solution sets for three operational uses of close-approach logic. For this study, satellite orbital motion is modeled using first-order secular perturbations caused by mass anomalies.

Alfano, Salvatore; Negron, David, Jr.

1993-06-01

409

Age determination of raccoons  

USGS Publications Warehouse

Age criteria, based on 61 skulls and eye lenses from 103 known-age captives, are described for separating raccoons (Procyon lotor) into eight age-classes as follows: young-of-the-year, 1, 2, 3, 4, 5, 6-7, > 7 years. Criteria studied were eye lens nitrogen, cranial suture closure, tooth wear and incisor cementum layers. Lens nitrogen increased rapidly up to 12 months of age, but at much reduced rate thereafter. Total lens nitrogen was useful only in separating young-of-the-year from adults. The closure sequence for five cranial sutures accurately divided the total known-age sample of males into seven groups, and the adults into five groups. The tooth wear criteria divided the known-age sample into five relative age groups, but aging of individuals by this method was inaccurate. Histological sectioning of known-age teeth was the best method of observing layering in the cementum tissue. The technique of basing estimation of age on cementum ring counts, although subjective, was accurate for aging individuals through their fourth year but tended to underestimate the age of animals over 4 years old. However, suture closure or tooth wear can be used to identify males over 4 years old. In field studies, technical difficulties limit the utility of age estimation by cementum layers. Maximum root thickness of the lower canine was accurate in determining the sex of individuals from 5 months to ,at least 48 months of age.

Grau, G .A.; Sanderson, G .C.; Rogers, J.P.

1970-01-01

410

Terahertz calorimetry: an absolute power meter for terahertz radiation and the absorptivity of the Herschel Space Observatory telescope mirror coating  

Microsoft Academic Search

A new calorimetric absolute power meter has been developed for THz radiation. This broad band THz power meter measures average power at ambient temperature and pressure, does not use a window, and is insensitive to polarization and time structure of THz radiation. The operation of the power meter is based on the calorimetric method: in order to determine the power

Tjeerd O. Klaassen; J. Niels Hovenier; Jacqueline Fischer; Gerd Jakob; Albrecht Poglitsch; Oren Sternberg

2004-01-01

411

Determinants of lemming outbreaks.  

PubMed

Population outbreaks in tundra rodents have intrigued scientists for a century as a result of their spectacular appearances and their general lessons in ecology. One outstanding question that has led to competing hypotheses is why sympatric lemmings and voles differ in regularity and shape of their outbreaks. Lemming outbreaks may be lost for decades while vole populations maintain regular population cycles. Moreover, when lemming populations eventually irrupt, they do so more steeply than the vole populations. Norwegian lemmings exhibited a large-scale outbreak synchronously with gray-sided voles in Finnmark, northern Fennoscandia, during 2006 to 2007 for the first time in two decades. Analyses of spatial variability of this outbreak across altitudinal gradients allowed us to identify determinants of the contrasting lemming and vole dynamics. The steeper lemming outbreak trajectories were caused by breeding and population growth during winter, when nonbreeding vole populations consistently declined. The differently shaped lemming and vole outbreaks appear to result from a particular demographic tactic of lemmings that evolved as an adaptation to the long and cold Arctic-Alpine winters. The lemming outbreak amplitude increased with altitude and vole density, indicating that lemming outbreaks are jointly facilitated by low temperatures and apparent mutualism with voles mediated by shared predators. High sensitivity to variation in climate and predation is likely to be the reasons why lemmings have more erratic population dynamics than sympatric voles. The combination of continued climatic warming and dampened vole cycles is expected to further decrease the frequency, amplitude, and geographic range of lemming outbreaks in tundra ecosystems. PMID:21245340

Ims, Rolf A; Yoccoz, Nigel G; Killengreen, Siw T

2011-01-18

412

Determinants of pediatric injuries.  

PubMed

Injuries are an important health issue for children. Previous research, however, has presented confusing and conflicting results on the determinants of childhood injuries, particularly psychosocial predictors, largely due to methodologic problems. The purpose of this analysis, based on a prospective follow-up study of 532 children, was to identify factors related to injuries encountered in a prepaid group practice during a 12-month period. Using logistic regression, we found four factors independently associated with the risk of at least one treated injury: high activity level, high rate of pediatric utilization for non-injury-related visits during the follow-up period, occurrence of a treated injury during the year preceding the follow-up period, and negative attitude toward medical care providers by the child's mother. In addition, four factors were found to be independent predictors of injuries judged severe enough to always warrant medical care: occurrence of a treated injury in the preceding year, high rate of pediatric utilization for non-injury-related visits during the follow-up period, working more than 15 hours a week outside the home by the child's mother, and more life events reported by the mother for the year preceding the follow-up period. Since family stressors are related specifically to the risk of more severe injuries, which are unlikely to escape medical attention, we conclude that these factors probably are related to the occurrence of common injuries of early childhood and not exclusively to utilization behavior. We therefore suggest that children from families with these characteristics be targeted for injury prevention strategies. PMID:3369398

Horwitz, S M; Morgenstern, H; DiPietro, L; Morrison, C L

1988-06-01

413

Determinants of lemming outbreaks  

PubMed Central

Population outbreaks in tundra rodents have intrigued scientists for a century as a result of their spectacular appearances and their general lessons in ecology. One outstanding question that has led to competing hypotheses is why sympatric lemmings and voles differ in regularity and shape of their outbreaks. Lemming outbreaks may be lost for decades while vole populations maintain regular population cycles. Moreover, when lemming populations eventually irrupt, they do so more steeply than the vole populations. Norwegian lemmings exhibited a large-scale outbreak synchronously with gray-sided voles in Finnmark, northern Fennoscandia, during 2006 to 2007 for the first time in two decades. Analyses of spatial variability of this outbreak across altitudinal gradients allowed us to identify determinants of the contrasting lemming and vole dynamics. The steeper lemming outbreak trajectories were caused by breeding and population growth during winter, when nonbreeding vole populations consistently declined. The differently shaped lemming and vole outbreaks appear to result from a particular demographic tactic of lemmings that evolved as an adaptation to the long and cold Arctic–Alpine winters. The lemming outbreak amplitude increased with altitude and vole density, indicating that lemming outbreaks are jointly facilitated by low temperatures and apparent mutualism with voles mediated by shared predators. High sensitivity to variation in climate and predation is likely to be the reasons why lemmings have more erratic population dynamics than sympatric voles. The combination of continued climatic warming and dampened vole cycles is expected to further decrease the frequency, amplitude, and geographic range of lemming outbreaks in tundra ecosystems.

Ims, Rolf A.; Yoccoz, Nigel G.; Killengreen, Siw T.

2011-01-01

414

Direct determination of the enthalpy of formation of MoB in synthesis from simple substances in an SHS system  

NASA Astrophysics Data System (ADS)

In a calorimetric bomb equipped with an electric microfurnace for heating a sample, self-propagating high-temperature synthesis (SHS) of molybdenum boride is realized in accordance with the reaction Mo (c) +B (amorph.)=MoB (c); the enthalpy of this reaction is measured, and the standard enthalpy of formation of molybdenum boride from metal molybdenum and crystaline boron is calculated: ?f H 0 (MoB,c,?,?)=103.9?1.2kJ/mole.

Lavut, E. G.; Chelovskaya, N. V.; Kashireninov, O. E.

1993-10-01

415

Lunar Prospector Orbit Determination Results.  

National Technical Information Service (NTIS)

The orbit support for Lunar Prospector (LP) consists of three main areas: (1) cislunar orbit determination, (2) rapid maneuver assessment using Doppler residuals, and (3) routine mapping orbit determination. The cislunar phase consisted of two trajectory ...

M. Beckman M. Concha

1998-01-01

416

When is sex environmentally determined?  

Microsoft Academic Search

THERE are several sex determining mechanisms which produce two sexes in a population (dioecy or gonochorism)1-5. In many of these, the offspring's sex is determined at or before conception, as in male or female heterogamety. In several organisms, however, the offspring's sex is determined later than conception, by some environmental influence upon the offspring. We consider here why these environmental

Eric L. Charnov; James Bull

1977-01-01

417

COLORIMETRIC DETERMINATION OF ZIRCONIUM WITH \\  

Microsoft Academic Search

A method of the colorimetric determination of zirconium with ; phenylfluron (2,3,7-trioxide-9-phenylcompound with its maximum light absorption ; at 535 m mu . The compound is soluble in ethanol, butanol, methyl ethyl ketone, ; isoamyl alcohol, butyl formate, and cyclohexanol. The ions which interfere with ; the determination are listed. The method can be adapted for the determination of ;

F. G. Zharovskiy; A. T. Philipenko

1957-01-01

418

DETERMINATION OF CALORIES BY NIR  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although NIR spectroscopy has been used to determine energy content of feeds, little is known about the capability of near-infrared (NIR) spectroscopy for the determination of available energy in foods for human consumption. Recent studies have been conducted to determine the utilizable energy in p...

419

Interactions of water with roasted and ground coffee in the wetting process investigated by a combination of physical determinations.  

PubMed

Three complementary techniques were used in this study to investigate the physical changes during wetting of roasted and ground coffee. Scanning electron microscopy (SEM) was found to provide indirect evidence of the presence of liquid water in the coffee particles. The effect of wetting on coffee closed porosity was studied by helium pycnometry, and finally, particle sizing was used to determine the swelling kinetics of coffee after wetting. Due to the solubilization of compounds, the presence of liquid water could be detected in the coffee cells by SEM. The technique was then used to investigate different water contents; for example, for roasted and ground coffee containing 1 g of water per gram of coffee on a dry basis, liquid water was present in cells only at the periphery of approximately 1.0 mm diameter particles. Coffee closed porosity decreased with increasing water content, as evidenced by pycnometry. For roasted and ground coffee containing 1 g of water per gram of coffee, results showed a closed porosity lower that 0.1 cm3/g ( approximately 20% of the closed porosity measured in dry particles). The decrease of closed porosity may be attributed to both (1) water filling cells' lumen and (2) plasticization of cell wall polymers, resulting in the matrix relaxation and increase of helium accessibility to the pores. Water binding to the matrix polymers was further investigated by calorimetric measurements. The integration of the endothermic peak of freezing water showed that approximately 0.15 g of water/g of coffee is nonfreezable water, that is, water bound to the matrix polymers. Finally, the use of particle sizing showed that the average volume of the coffee particles with 1 g of water/g of coffee increased by up to 20-23% at 10-15 min following wetting. Moisture diffusion coefficients in coffee particles [( approximately 2-3) x 10(-11) m2 s(-1)] were approximated by fitting the swelling curves with a model of diffusion. The observed results may give information about homogeneity and the physical state of water in wetted roasted coffee and thus increase the understanding of the mechanisms of molecular mass transfer during extraction. PMID:17373809

Mateus, Maria-L; Rouvet, Martine; Gumy, Jean-C; Liardon, Rémy

2007-03-21

420

Determining a Soil's Textural Classification  

NSDL National Science Digital Library

In this activity students use screen sieves to determine the percent of sand, silt, and clay in a soil sample. They then use a tertiary soil diagram to determine the generic soil name of their sample. Students will learn to use particle size analysis as a tool to determine a soil's texture and understand the role of sand, silt, and clay sized particles in a soil. The site has a link to obtain the required soil diagram.

421

Uncountable products of determined groups need not be determined  

NASA Astrophysics Data System (ADS)

If H is a dense subgroup of G, we say that H determines G if their groups of characters are topologically isomorphic when equipped with the compact open topology. If every dense subgroup of G determines G, then we say that G is determined. The importance of this property is justified by the recent generalizations of Pontryagin-van Kampen duality to wider classes of topological Abelian groups. Among other results, we show (a) determines the product if and only if I is countable, (b) a compact group is determined if and only if its weight is countable. These answer questions of Comfort, Raczkowski and the third listed author. Generalizations of the above results are also given.

Hernández, Salvador; Macario, Sergio; Trigos-Arrieta, F. Javier

2008-12-01

422

Gender Determination using Fingertip Features  

Microsoft Academic Search

Several previous studies have investigated the gender difference of the fingerprint features. However, regarding to the statistical significance of such differences, inconsistent results have been obtained. To resolve this problem and to develop a method for gender determination, this work proposes and tests three fingertip features for gender determination. Fingerprints were obtained from 115 normal healthy adults and comprised of

Jen-Feng Wang; Chen-Liang Lin; Yung-Hsien Chang; Mark L. Nagurka; Chen-Wen Yen; Chinson Yeh

2008-01-01

423

Determinate Sentencing and Prisoner Attitudes  

Microsoft Academic Search

An experiment was conducted to investigate the possible effects of determinate sentencing. Fifty-eight prisoners were tested on six variables: Cynicism, Optimism, Extrinsic Motivation, Intrinsic Motivation, program involvement, andprogram satisfaction. Some prisoners were retested with instructions to respondas if they had been given a determinate sentence, and a control group was told to respond as if improvements had been made in

Robert J. Homant

1978-01-01

424

Chromatographic determination of plant saponins  

Microsoft Academic Search

The methods used for saponin determination in plant materials are presented. It is emphasised that the biological and spectrophotomeric methods still being used for saponin determination provide, to some extent, valuable results on saponin concentrations in plant material. However, since they are sensitive to the structural variation of individual saponins they should be standardized with saponin mixtures isolated from the

W. A Oleszek

2002-01-01

425

Ultrasonic Determination of Body Composition.  

National Technical Information Service (NTIS)

The object of the study was to determine the feasibility of using ultrasonic techniques to determine the volume of fat, muscle, and bone tissue of the living body. Ultrasonic equipment, including a mechanical scanning and recording device was used to prod...

J. R. Stouffer

1968-01-01

426

Empirical Determinants of Bargaining Power  

Microsoft Academic Search

This paper empirically investigates what determine bargaining power between a lender and a borrower who have continuing transactional relationships. Bargaining power is proxied by which side of the transaction, i.e. the lender or the borrower, usually incurs a shoe-leather cost when they have contact. The proxy is regressed on three types of variables that can potentially determine distribution: (i) lender's

Hirofumi Uchida

2006-01-01

427

Method of determining glass durability  

DOEpatents

A process is described for determining one or more leachate concentrations of one or more components of a glass composition in an aqueous solution of the glass composition by identifying the components of the glass composition, including associated oxides, determining a preliminary glass dissolution estimator, {Delta}G{sub p}, based upon the free energies of hydration for the component reactant species, determining an accelerated glass dissolution function, {Delta}G{sub a}, based upon the free energy associated with weak acid dissociation, {Delta}G{sub a}{sup WA}, and accelerated matrix dissolution at high pH, {Delta}G{sub a}{sup SB} associated with solution strong base formation, and determining a final hydration free energy, {Delta}G{sub f}. This final hydration free energy is then used to determine leachate concentrations for elements of interest using a regression analysis and the formula log{sub 10}(N C{sub i}(g/L))=a{sub i} + b{sub i}{Delta}G{sub f}. The present invention also includes a method to determine whether a particular glass to be produced will be homogeneous or phase separated. The present invention is also directed to methods of monitoring and controlling processes for making glass using these determinations to modify the feedstock materials until a desired glass durability and homogeneity is obtained. 4 figs.

Jantzen, C.M.; Pickett, J.B.; Brown, K.G.; Edwards, T.B.

1998-12-08

428

Erroneous theories of sex determination.  

PubMed Central

Throughout the major part of history, theories of sex determination had to be formulated in the absence of knowledge of ova and spermatozoa. The most persistent theory postulated that males are associated with the right parental side and females with the left side. At the end of the 19th century, sex was thought to be determined by nutrition. Recent findings regarding bilateral asymmetry in human hermaphrodites and of temperature dependent sex determination in reptiles may restore a small degree of credibility to certain theories predating the discovery of sex chromosomes. Images

Mittwoch, U

1985-01-01

429

510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Reproducibility when testing PreservCyt liquid Pap clinical specimens containing target organism has not been determined. ... More results from www.fda.gov/downloads/biologicsbloodvaccines/safetyavailability

430

Determination of the Hubble constant.  

National Technical Information Service (NTIS)

The possibility of an alternative determination of the distance scale of the Universe and the Hubble constant based on the numerical analysis of the hierarchical nature of the large scale Universe (galaxies, clusters and superclusters) is proposed. The re...

V. G. Gurzadyan V. V. Harutyunyan A. A. Kocharyan

1990-01-01

431

Determining the Library User's Need.  

National Technical Information Service (NTIS)

The video discusses steps a library staff can take in order to determine a patron's exact need. It also discusses how to find out specifics, create the right atmosphere, and interview the library user.

1994-01-01

432

Asteroid searching and orbit determination  

NASA Astrophysics Data System (ADS)

This lecture reviews some basic information on asteroids relating to the ASTROD project, as well as the current progress on asteroid searching. The online resources on asteroid orbit determination are also introduced.

Zhu, Jin; Gao, Jian; Guan, Min; Yang, Bin

433

Determination of Rubidium in Seawater.  

National Technical Information Service (NTIS)

Rubidium concentrations in seawater from various locations and depths to 3,900 m were determined using two independent techniques--direct flame photometry and mass spectrometry. Results of these two techniques agree within estimated errors and indicate th...

K. C. Pillai R. C. Smith T. J. Chow T. R. Folsom

1965-01-01

434

Laboratory Determination of Hydraulic Conductivity  

NSDL National Science Digital Library

From D.B. McWhorterand D. K. Sunda's 1977 Ground-Water Hydrology and Hydraulics, this two page excerpt outlines and details Laboratory Determination of Hydraulic Conductivity. Here, visitors will find illustrations and formula to understand the concept.

2008-02-07

435

Determinate Sentencing and Prisoner Attitudes.  

ERIC Educational Resources Information Center

In an experiment to investigate the possible effects of determinate sentencing, 48 prisoners were tested on six variables. Although there was some indirect evidence that the indeterminate sentence is a source of tension, the issue remains open. (Author)

Homant, Robert J.

1978-01-01

436

Determining Regulatory Authority for Antimicrobial ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Decision Tree for Determining whether any Particular Antimicrobial Intervention for Food is Regulated by the Environmental Protection Agency or ... More results from www.fda.gov/food/ingredientspackaginglabeling/packagingfcs

437

Dietary Determinants of Prostate Cancer.  

National Technical Information Service (NTIS)

Prostate Cancer (PCa) accounts for nearly 30% of all newly diagnosed cancers among American men. Epidemiologic studies suggest that dietary factors may be important in the etiology of this disease. The objective of our research is to determine how nutriti...

L. W. Chu

2006-01-01

438

Thorium: Determination by CDTN, Brazil  

NASA Astrophysics Data System (ADS)

One of the tasks of the Radiochemical Sector, CDTN/CNEN, Brazil, is to meet the clients' analytical needs. The Sector has been facing the challenges of determining several elements in diversified matrixes from all over the country since the sixties. It has been giving analytical support to universities, industries, environmental monitoring programs, research institutes. Due to the growing need to determine thorium isotopes through the years it was necessary to work out a routine procedures. Nowadays the determination of thorium consists of a well established routine whose procedures are applied to grouped samples according to their kind, physical state, matrix interference, detection limits and number of samples. This paper describes the methods used by CDTN to determine232Th by neutron activation analysis and230Th and228Th by radiochemical separations and alpha spectrometry in several matrixes.

Menezes, M. A. B. C.; Sabino, C. V. S.

1999-01-01

439

Gender determination of avian embryo  

DOEpatents

Disclosed is a method for gender determination of avian embryos. During the embryo incubation process, the outer hard shells of eggs are drilled and samples of allantoic fluid are removed. The allantoic fluids are directly introduced into an ion mobility spectrometer (IMS) for analysis. The resulting spectra contain the relevant marker peaks in the positive or negative mode which correlate with unique mobilities which are sex-specific. This way, the gender of the embryo can be determined.

Daum, Keith A. (Idaho Falls, ID); Atkinson, David A. (Idaho Falls, ID)

2002-01-01

440

Radiochemical determination of technetium-99  

Microsoft Academic Search

A radiochemical method has been developed for determination of ⁹⁹Tc by which both the chemical yield and the yield-corrected amount of ⁹⁹Tc in a sample may be determined. The chemical yield estimation is based upon counting of low energy internal-conversion electrons from the added isotopic tracer ⁹⁷Tc. Uncertainties in the ⁹⁹Tc and yield estimates depend on the amount of ⁹⁷Tc

J. H. Kaye; J. A. Merrill; R. R. Kinnison; M. S. Rapids; N. E. Ballou

1982-01-01

441

Radium determination in mineral waters  

Microsoft Academic Search

We have determined the Radium concentration in several samples of natural mineral waters. Using a small volume of sample (? 100 ml), Ra isotopes are preconcentrated by adsorption onto a MnO2-impregnated cotton-filter, leached from the column with a hydroxylamine-HCl mixture and coprecipitated with BaSO4. 226Ra concentration has been determined using a low-background proportional counter and also from ?-spectrometry. The results

J. C. Bayés; E. Gómez; F. Garcias; M. Casas; V. Cerdá

1996-01-01

442

Energy determination for RUNJOB experiment  

NASA Astrophysics Data System (ADS)

We summarize various methods of energy determination applicable for RUNJOB experiments and discuss the internal relation of each method with use of a trial model, fire-ball emission decaying isotropically into ? 's (? 0 ? 2? ). Since the energy determination is closely related to the chamber sturcture, we also touch briefly the characteristics of chamber structure used in RUNJOB-program, slightly different from current emulsion chamber available for cosmic ray observation at both mountain and stratosphere levels.

Apanasenko, A. V.

1999-08-01

443

EXPERIMENTAL DETERMINATION OF UNMANNED AIRCRAFT  

Microsoft Academic Search

This paper presents the methodology used in the experimental determination of the inertial properties of an unmanned aerial vehicle (UAV). This UAV is a prototype aircraft made of ply wood, balsa wood and aluminum, with a wingspan of 2,5m. A compound-pendulum is used to determine moments of inertia about transversal, longitudinal and vertical axes. The vertical location of the center

444

Experimental Determination of Dawsonite Stability and Reactivity: Implications for Geological CO2 Sequestration  

SciTech Connect

Over the last decade, a significant research effort has focused on determining the feasibility of sequestering large amounts of CO{sub 2} in deep, permeable geologic formations to reduce carbon dioxide emissions to the atmosphere. Most models indicate that injection of CO{sub 2} into deep sedimentary formations will lead to the formation of various carbonate minerals, including the common phases calcite (CaCO{sub 3}), dolomite (CaMg(CO{sub 3}){sub 2}), magnesite (MgCO{sub 3}), siderite (FeCO{sub 3}), as well as the far less common mineral, dawsonite (NaAlCO{sub 3}(OH){sub 2}). Nevertheless, the equilibrium and kinetics that control the precipitation of stable carbonate minerals are poorly understood and few experiments have been performed to validate computer codes that model CO{sub 2} sequestration. In order to reduce this uncertainty we measured the solubility of synthetic dawsonite according to the equilibrium: NaAlCO{sub 3}(OH){sub 2(cr)} + 2H{sub 2}O{sub 1} {r_equilibrium}Al(OH){sub 4}{sup -} + HCO{sub 3}{sup -} + Na{sup +} + H{sup +}, from under- and oversaturated solutions at 50-200 C in basic media at 1.0 mol {center_dot} kg{sup -1} NaCl. The solubility products (Q{sub s}) obtained were extrapolated to infinite dilution to obtain the solubility constants (K{sub s}{sup o}). Combining the fit of these logK{sub s}{sup o} values and fixing {Delta}C{sub pJ}{sup o} at -185.5J {center_dot} mol{sup -1} {center_dot} K{sup -1} at 25 C, which was derived from the calorimetric data of Ferrante et al. [Ferrante, M.J., Stuve, J.M., and Richardson, D.W., 1976. Thermodynamic data for synthetic dawsonite. U.S. Bureau of Mines Report Investigation, 8129, Washington, D.C., 13p.], the following thermodynamic parameters for the dissolution of dawsonite were calculated at 25 C: {Delta}G{sub r}{sup o} = 102.1 kJ {center_dot} mol{sup -1}, {Delta}H{sub r}{sup o} = 97.0 kJ {center_dot} mol{sup -1} and {Delta}s{sub r}{sup o} = -17.1 J {center_dot} mol{sup -1} {center_dot} K{sup -1}. Subsequently, we were able to derive values for the Gibbs energy of formation {Delta}{sub {line_integral}}G{sup 0}{sub 298.15} = -1782 {+-} 2 kJ {center_dot} mol{sup -1}), enthalpy of formation ({Delta}{sub {line_integral}}H{sup o}{sub 298.15} = -1960 {+-} 7 kJ {center_dot} mol{sup -1}) and entropy (S{sup o}{sub 298.15} = 121 {+-} 2 J {center_dot} mol{sup -1} {center_dot} K{sup -1}) of dawsonite. These results are within the combined experimental uncertainties of the values reported by Ferrante et al. (1976). Predominance diagrams are presented for the dawsonite/boehmite and dawsonite/bayerite equilibria at 100 C in the presence of a saline solution with and without silica-containing minerals.

Benezeth, Pascale [Laboratoire des Mecanismes et Transferts en Geologie, Toulouse, France; Palmer, Donald [ORNL; Anovitz, Lawrence {Larry} M [ORNL; Horita, Juske [ORNL

2007-01-01

445

Cytotoxicity determination without photochemical artifacts.  

PubMed

A study was performed to improve cytotoxicity determinations by eliminating flavin-mediated photosensitization from tests with KB cells, NCI-H69 cells, P-glycoprotein expressing KBC5-8 cells, MRP1-expressing H69AR cells, and A240286S human lung adenocarcinoma cells. Growth inhibition by cis-platin, doxorubicin, etoposide, gemcitabine, taxol, vincristine, vinblastine, and vinorelbine was determined under flavin-protecting conditions using flavin-free culture media with fetal bovine serum as the only source of flavins. As compared to conventional tests, the IC50 values determined under flavin-protecting conditions reflected increased apparent drug cytotoxicities, and were flawlessly reproducible. Flavin-mediated photosensitization should, therefore, be strictly eliminated from in vitro experiments involving cytotoxic and other drugs. PMID:15890237

Heuser, Michael; Kopun, Marijana; Rittgen, Werner; Granzow, Christof

2004-12-08

446

On the role of the functional group in determining the strength of hydrophobic interactions in aqueous solutions of ?-amino acid derivatives  

Microsoft Academic Search

Calorimetric measurements were carried out at 25°C on binary aqueous solutions containing N-acetyl derivatives of the following a-amino acids: glycine, alanine, valine, leucine, norleucine, aspartic acid, glutamic acid, phenylalanine, methionine, asparagine, glutamine, cysteine, histidine, serine. The N-acetyl derivative of the a-amino acid proline was also studied. The results obtained have been used to calculate the pairwise enthalpic interaction coefficients and

Giuseppina Castronuovo; Vittorio Elia; Filomena Velleca

1996-01-01

447

Decoherence, determinism and chaos revisited  

NASA Astrophysics Data System (ADS)

We suggest that the derivation of the free space Maxwell Equations for classical electromagnetism, using a discrete ordered calculus developed by L. H. Kauffman and T. Etter, necessarily pushes the discussion of determinism in natural science down to the level of relativistic quantum mechanics and hence renders the mathematical phenomena studied in deterministic chaos research irrelevant to the question of whether the world investigated by physics is deterministic. We believe that this argument reinforces Suppes' contention that the issue of determinism versus indeterminism should be viewed as a Kantian antinomy incapable of investigation using currently available scientific tools.

Noyes, H. P.

1994-11-01

448

Method for determining communicative value  

US Patent & Trademark Office Database

A method of determining which users are experts and which tags are appropriate without some of the disadvantages of the prior art is described. The level of a user's expertise is determined based on previous tags, the categorization of one or more tags, and the rating of the tags previously left by the user. The appropriateness of a tag is based on previous tagging of information by the user, by the number of times a user has tagged information with the same categorization, and the rating of a user.

Seligmann; Doree Duncan (New York, NY); Singh; Ajita John (Holmdel, NJ); Kelkar; Shreeharsh (Summit, NJ)

2012-07-31

449

Decoherence, determinism and chaos revisited  

SciTech Connect

We suggest that the derivation of the free space Maxwell Equations for classical electromagnetism, using a discrete ordered calculus developed by L.H. Kauffman and T. Etter, necessarily pushes the discussion of determinism in natural science down to the level of relativistic quantum mechanics and hence renders the mathematical phenomena studied in deterministic chaos research irrelevant to the question of whether the world investigated by physics is deterministic. We believe that this argument reinforces Suppes` contention that the issue of determinism versus indeterminism should be viewed as a Kantian antinomy incapable of investigation using currently available scientific tools.

Noyes, H.P.

1994-11-15

450

The Determination of Partial Moments  

Microsoft Academic Search

In statistical decision theory, computations often involve the partial moments of a random variable. Several methods for determining partial moments are discussed, including direct calculation, the use of general formulas which apply to entire families of distributions, and the use of partial moment generating functions. Using these methods, formulas (some involving recursive relationships) are developed for the partial moments of

Robert L. Winkler; Gary M. Roodman; Robert R. Britney

1972-01-01

451

Determination of Uranium by Fluorometry.  

National Technical Information Service (NTIS)

The purpose of this work is to investigate the analytical parameters for the fluorometric determination of uranium applied in the analysis of geological materials. A mixture of 9 parts sodium fluoride, 45.5 parts sodium carbonate and 45.5 parts potassium ...

V. Leenanupan N. Ratanalert

1984-01-01

452

Performing Determinism: Disability Culture Poetry  

Microsoft Academic Search

“Performing Determinism” discusses the performance of disability through poetry: the instability of language, the ability of words to clasp both generic and specific meaning, and the gaps that surround the performances of self. Disability culture acts as a frame for the inquiry, as the essay discusses crip aesthetics, crip critical practice, and the embodiment of language. In the reading of

Petra Kuppers

2007-01-01

453

Determinants of Nuclear Weapons Proliferation  

Microsoft Academic Search

Nuclear weapons proliferation is a topic of intense interest and concern among both academics and policy makers. Diverse opinions exist about the determinants of proliferation and the policy options to alter proliferation incentives. We evaluate a variety of explanations in two stages of nuclear proliferation, the presence of nuclear weapons production programs and the actual possession of nuclear weapons. We

Dong-Joon Jo; Erik Gartzke

2007-01-01

454

Upper Bounds for Regularized Determinants.  

National Technical Information Service (NTIS)

Let E be a holomorphic vector bundle on a compact Kahler manifold X. If the authors fix a metric h on E, they get a Laplace operator delta acting upon smooth sections of E over X. Using the zeta function of delta, one defines its regularized determinant d...

H. Gillet C. Soule

1997-01-01

455

Freedom and Determinism: A Framework  

Microsoft Academic Search

Thoughts about freedom and determinism have engaged philosophers since the days of ancient Greece., On the one hand, we generally regard ourselves as free and autonomous beings who are responsible for the ac-tions that we perform. But this idea of ourselves appears to conflict with a variety of attitudes that we also have about the inevitable workings of the world

Joseph Keim Campbell; Michael O'Rourke; David Shier

456

Using Parallax to Determine Distances  

NSDL National Science Digital Library

This activity is designed to give students a better understanding of what parallax is and to gain some experience in using it. They will devise a method to calculate the distance of objects using observational data, describe how our eyes use parallax to determine the distance of objects, and make estimates of distances using parallax.

457

Determining Salinity by Simple Means.  

ERIC Educational Resources Information Center

This paper describes the construction and use of a simple salinometer. The salinometer is composed, mainly, of a milliammeter and a battery and uses the measurement of current flow to determine the salinity of water. A complete list of materials is given, as are details of construction and operation of the equipment. The use of the salinometer in…

Schlenker, Richard M.

458

Determinants of Fashion Attributes' Importance  

Microsoft Academic Search

What determines the importance of fashion attributes in the purchase of clothing? The present study attempts to answer one question. Can values, demographics, and personality traits be combined in one model to predict the importance of fashion attributes to consumers? It explores a framework that proceeds from demographics (age and gender) and social values to role relaxation to conformity to

Aviv Shoham

2003-01-01

459