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1

Thermochemistry of Uranium Compounds: XVI, Calorimetric Determination of the Standard Molar Enthalpy of Formation at 298.15 K, Low-Temperature Heat Capacity, and High-Temperature Enthalpy Increments of UO sub 2 (OH) Sub 2 /Center DOT/ H sub 2 O (Schoepite).  

National Technical Information Service (NTIS)

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 ...

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

1987-01-01

2

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

3

Determination of the calorimetric energy in extensive air showers  

Microsoft Academic Search

The contribution of different components of an air shower to the total energy deposit in the atmosphere, for different angles and primary particles, was studied using the CORSIKA air shower simulation code. The amount of missing energy, parameterized in terms of the calorimetric energy, was calculated. The results show that this parameterization varies less than 1% with angle or observation

Henrique M. J. Barbosa; Fernando Catalani; Jose A. Chinellato; Carola Dobrigkeit

2004-01-01

4

Calorimetric measurements of 163holmium decay as tools to determine the electron neutrino mass  

NASA Astrophysics Data System (ADS)

We compute the spectrum of ``calorimetric'' energy in the electron capture decay of 163Ho. A calorimetric experiment would yield an excellent determination of the (163Ho, 163Dy) mass difference. The proximity of the spectral endpoint to an atomic resonance makes the fraction of events that are sensitive to a non-zero neutrino mass superior in 163Ho decay than in tritium decay. On leave of absence from Istituto di Fisica dell'Università, Rome, Italy.

de Rújula, A.; Lusignoli, M.

1982-12-01

5

Determination of the calorimetric energy in extensive air showers  

NASA Astrophysics Data System (ADS)

The contribution of different components of an air shower to the total energy deposit in the atmosphere, for different angles and primary particles, was studied using the CORSIKA air shower simulation code. The amount of missing energy, parameterized in terms of the calorimetric energy, was calculated. The results show that this parameterization varies less than 1% with angle or observation level. The dependence with the primary mass is less than 5% and, with the high energy hadronic interaction model, less than 2%. The systematic error introduced by the use of just one parameterization of the missing energy correction function, for an equal mixture of proton and iron at 45°, was calculated to be below 3%. We estimate the statistical error due to shower-to-shower fluctuations to be about 1%.

Barbosa, H. M. J.; Catalani, F.; Chinellato, J. A.; Dobrigkeit, C.

2004-11-01

6

Calorimetric determination of fragility in glass forming liquids: Tf vs. T g-onset methods.  

PubMed

The calorimetric determination of the fragility m-index is compared using the T f and T g-onset methods for typical metallic and molecular glass forming systems of Pd39Ni10Cu30P21, glycerol, triacetin and propylene carbonate. The results are evaluated by referring to the standard m-values determined from the kinetic measurements of the viscosity or structural relaxation time in the supercooled liquid regimes. The m-indexes derived from the T f method are found to generally agree well with the kinetic measurements for all the systems. However, a large deviation is shown between the m-indexes calculated with the T g-onset method and the kinetic results for the fragile liquids of triacetin and propylene carbonate, indicating the calorimetric determination of the fragility m-indexes in terms of the T f method produces less uncertainty. PMID:24965151

Chen, Zeming; Li, Zijing; Zhang, Yaqi; Liu, Riping; Tian, Yongjun; Wang, Li-Min

2014-06-01

7

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

8

Calorimetric determination of dissolution enthalpy with a novel flow-through method.  

PubMed

A new calorimetric flow-through system for determining the enthalpies of dissolution with small amount of solids (<1mg) was developed. The system was designed to be used as an add-on cell with a 4 ml twin heat conduction calorimeter 2277 TAM but the principle is adoptable also for other heat conduction calorimeters. The system was tested with two salts (NaCl, KCl), sucrose and different polymorphic forms of theophylline at 25 degrees C and 40 degrees C by using water as the solvent. The system gave more accurate and precise results at 25 degrees C. The precision was not affected by the extent of the dissolution enthalpy. The accuracy was dependent on the calibration utilized but even the normal electrical calibration gave acceptable values. The results obtained at 40 degrees C were also acceptable but not as good as at 25 degrees C due to heat leaks. The effect of heat leaks can be minimized by heating the inflowing solvent outside the calorimeter prior to entering the flow-through cell. PMID:20674217

Lehto, Vesa-Pekka; Tenho, Mikko; Hämäläinen, Olli-Pekka; Salonen, Jarno

2010-12-01

9

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

10

Electronic calorimetric computer  

NASA Technical Reports Server (NTRS)

Electronic calorimetric computer calculates nuclear reactor thermal power output to a nominal accuracy of 1 percent. Heat balance is determined by an electronic approach. The thermal power is calculated using the inlet and outlet temperatures and the volume of cooling water and is displayed by a digital readout system.

Heckelman, J. D.

1968-01-01

11

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

NASA Technical Reports Server (NTRS)

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

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

1990-01-01

12

Calorimetric determination of the thermoneutral potential for Li\\/BrCl in SOCl2 (BCX) cells  

Microsoft Academic Search

Proliferation of lithium cells into large modular battery packs are projected for future space applications. Assuring battery design safety while maintaining high energy density requires accurate and precise knowledge of the thermal parameters of the battery cell. Specifically, the thermoneutral potential was determined using heat conduction calorimetry on Li\\/BrCl in SOCl2 (BCX) DD-cells and compared to measurements obtained on Li\\/SOCl2

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

1991-01-01

13

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

14

Calorimetric determination of the thermoneutral potential for Li/BrCl in SOCl2 (BCX) cells  

NASA Technical Reports Server (NTRS)

Proliferation of lithium cells into large modular battery packs are projected for future space applications. Assuring battery design safety while maintaining high energy density requires accurate and precise knowledge of the thermal parameters of the battery cell. Specifically, the thermoneutral potential was determined using heat conduction calorimetry on Li/BrCl in SOCl2 (BCX) DD-cells and compared to measurements obtained on Li/SOCl2 D-cells. Over 20 to 60 C, the Li/BCX cells were found to have a thermoneutral potential significantly higher (near 4.0 volts) than that for the Li/SOCl2 cells tested. The higher heat generation measured during discharge reflects the higher electrochemical polarization observed with the BCX cells.

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

1991-01-01

15

Calorimetric determination of the thermoneutral potential for Li/BrCl in SOCl2 (BCX) cells  

NASA Astrophysics Data System (ADS)

Proliferation of lithium cells into large modular battery packs are projected for future space applications. Assuring battery design safety while maintaining high energy density requires accurate and precise knowledge of the thermal parameters of the battery cell. Specifically, the thermoneutral potential was determined using heat conduction calorimetry on Li/BrCl in SOCl2 (BCX) DD-cells and compared to measurements obtained on Li/SOCl2 D-cells. Over 20 to 60 C, the Li/BCX cells were found to have a thermoneutral potential significantly higher (near 4.0 volts) than that for the Li/SOCl2 cells tested. The higher heat generation measured during discharge reflects the higher electrochemical polarization observed with the BCX cells.

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

1991-05-01

16

Calorimetric determination of energetics of solid solutions of UO 2+ x with CaO and Y 2O 3  

NASA Astrophysics Data System (ADS)

Quantitative study of thermodynamic properties of solid solutions of UO 2+ x with divalent and trivalent oxides is important for predicting the behavior of oxide fuel. Although early literature work measured vapor pressure in some of these solid solutions, direct calorimetric measurements of enthalpies of formation have been hampered by the refractory nature of such oxides. First measurements of the enthalpies of formation in the systems UO 2+ x-CaO and UO 2+ x-YO 1.5, obtained by high-temperature oxide melt solution calorimetry, are reported. Both systems show significantly negative (exothermic) heats of formation from binary oxides (UO 2, plus O 2 and CaO or YO 1.5, as well as from UO 2 plus UO 3 and CaO or YO 1.5), consistent with reported free energy measurements in the urania-yttria system. The energetic contributions of oxygen content (oxidation of U 4+) and of charge balanced ionic substitution as well as defect clustering are discussed. Behavior of urania-yttria is compared to that of corresponding systems in which the tetravalent ion is Ce, Zr, or Hf. The substantial additional stability in the solid solutions compared to pure UO 2+ x may retard, in both thermodynamic and kinetic sense, the oxidation and leaching of spent fuel to form aqueous U 6+ and solid uranyl phases.

Mazeina, Lena; Navrotsky, Alexandra; Greenblatt, Martha

2008-02-01

17

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

SciTech Connect

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

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

1994-10-01

18

The VLT-FLAMES Tarantula Survey. XVI. The optical and NIR extinction laws in 30 Doradus and the photometric determination of the effective temperatures of OB stars  

NASA Astrophysics Data System (ADS)

Context. The commonly used extinction laws of Cardelli et al. (1989, ApJ, 345, 245) have limitations that, among other issues, hamper the determination of the effective temperatures of O and early B stars from optical and near-infrared (NIR) photometry. Aims: We aim to develop a new family of extinction laws for 30 Doradus, check their general applicability within that region and elsewhere, and apply them to test the feasibility of using optical and NIR photometry to determine the effective temperature of OB stars. Methods: We use spectroscopy and NIR photometry from the VLT-FLAMES Tarantula Survey and optical photometry from HST/WFC3 of 30 Doradus and we analyze them with the software code CHORIZOS using different assumptions, such as the family of extinction laws. Results: We derive a new family of optical and NIR extinction laws for 30 Doradus and confirm its applicability to extinguished Galactic O-type systems. We conclude that by using the new extinction laws it is possible to measure the effective temperatures of OB stars with moderate uncertainties and only a small bias, at least up to E(4405-5495) ~ 1.5 mag. Appendices are available in electronic form at http://www.aanda.org

Maíz Apellániz, J.; Evans, C. J.; Barbá, R. H.; Gräfener, G.; Bestenlehner, J. M.; Crowther, P. A.; García, M.; Herrero, A.; Sana, H.; Simón-Díaz, S.; Taylor, W. D.; van Loon, J. Th.; Vink, J. S.; Walborn, N. R.

2014-04-01

19

Calorimetric gas sensor  

DOEpatents

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

Ricco, Antonio J. (Albuquerque, NM); Hughes, Robert C. (Cedar Crest, NM); Smith, James H. (Albuquerque, NM); Moreno, Daniel J. (Albuquerque, NM); Manginell, Ronald P. (Albuquerque, NM); Senturia, Stephen D. (Brookline, MA); Huber, Robert J. (Bountiful, UT)

1998-01-01

20

Calorimetric gas sensor  

DOEpatents

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

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

1998-11-10

21

Inhibition of collagen XVI expression reduces glioma cell invasiveness.  

PubMed

Glioblastomas are characterized by an intense local invasiveness that limits surgical resection. One mechanism by which glioma cells enforce their migration into brain tissue is reorganization of tumour associated extracellular matrix (ECM). Collagen XVI is a minor component of connective tissues. However, in glioblastoma tissue it is dramatically upregulated compared to the ECM of normal cortex. The aim of this study is to delineate tumour cell invasion and underlying mechanisms involving collagen XVI by using a siRNA mediated collagen XVI knockdown model in U87MG human glioblastoma cells. Knockdown of collagen XVI resulted in decreased invasiveness in Boyden chamber assays, and in a reduction of focal adhesion contact numbers per cell. Gene expression was upregulated for protocadherin 18 and downregulated for kindlin-1 and -2. Proliferation was not affected while flow cytometric analysis demonstrated reduced ?1-integrin activation in collagen XVI knockdown cells. We suggest that in glioblastoma tissue collagen XVI may impair the cell-cell interaction in favour of enhancement of invasion. The modification of the ?1-integrin activation pattern through collagen XVI might be a molecular mechanism to further augment the invasive phenotype of glioma cells. Elucidating the underlying mechanisms of glioma cell invasion promoted by collagen XVI may provide novel cancer therapeutic approaches in neurooncology. PMID:21471710

Bauer, Richard; Ratzinger, Sabine; Wales, Lynn; Bosserhoff, Anja; Senner, Volker; Grifka, Joachim; Grässel, Susanne

2011-01-01

22

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

23

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2010 CFR

...false Standard XVI-Student activities. 36... BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE...physical activities, student government, and cultural affairs. The activity program...program. (a) All student activities...

2009-04-01

24

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2010 CFR

...false Standard XVI-Student activities. 36... BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE...physical activities, student government, and cultural affairs. The activity program...program. (a) All student activities...

2010-04-01

25

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

26

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

27

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

28

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

29

Immobilized enzymes – A simple calorimetric method for the determination of the catalytic activity 1 Presented at the Twelfth Ulm-Freiberg Conference, Freiberg, Germany, 19–21 March 1997 1  

Microsoft Academic Search

The results communicated in this paper show that rapid and reliable information about the activity of immobilized enzymes follows from calorimetric measurements. The study was done using spherical and plain carriers as well as different enzymes (urease, glucose-oxidase, invertase). The enzyme thermistor developed by Danielsson et al. was used as a measuring system. This measuring system was applied to investigate

Hagen Graebner; Ulrike Georgi; Regina Hüttl; Gert Wolf

1998-01-01

30

A calorimetric system for metabolic studies of newborn babies.  

PubMed

This paper describes a closed circuit calorimetric system designed to determine the amount of energy required for synthesis of new tissue in a newborn baby. This amount can be estimated from the difference between indirect and direct calorimetric measurements. The system allows the simultaneous measurement of oxygen consumption, carbon dioxide production, evaporative water loss and heat loss through convection and radiation in newborn babies under 2.5 kg bodyweight. The babies are exposed to a well defined climate, they can be observed continuously and are fed via a nasogastric tube during the experiment, which may last 24 h or more. Special features of the system are the compensation methods for O2 and CO2 measurements and the double gradient layer for the measurement of dry heat loss. The overall accuracy of the system is of the order of 0.1 W. The value obtained for the energy cost of growth is in close agreement with Hommes' theoretical estimate. PMID:3987209

Dane, H J; Holland, W P; Sauer, P J; Visser, H K

1985-02-01

31

Calorimetric Investigation of Deuterated Palladium Electrodes.  

National Technical Information Service (NTIS)

Calorimetric experiments were conducted to verify the caloric claims by Fleischmann and Pons. A twin-cell heat conduction calorimeter was used, rather than the quasiadiabatic instrumentation of the original investigation. Under similar electrochemical con...

C. W. Walker E. J. Plichta S. Gilman S. Slane T. R. Jow

1991-01-01

32

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

33

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

34

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

35

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

36

Calorimetric equipment for measuring magnetic losses  

Microsoft Academic Search

The above calorimetric equipment with an “adiabatic” sheathing eliminates almost completely the heat exchange between the calorimeter and the ambient medium. The equipment is suitable for measuring losses in toroidal magnetically soft samples (with an external diameter not exceeding 60 mm), when they are magnetized with alternating currents of several megahertz.

V. V. Kogen-Dalin; Khusein Nigm

1965-01-01

37

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

38

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

39

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

Federal Register 2010, 2011, 2012, 2013

...Social Security Ruling, SSR 13-2p.; Titles II and XVI: Evaluating Cases Involving...SSR rescinds and replaces SSR 82-60, Titles II and XVI: Evaluation of Drug Addiction...Security. POLICY INTERPRETATION RULING TITLES II AND XVI: EVALUATING CASES...

2013-02-20

40

Calorimetric measurement and modelling of the equivalent series of capacitors  

NASA Astrophysics Data System (ADS)

The equivalent series resistance of polypropylene capacitors has been determined under rated voltage, in the range 1 kHz 1 MHz, between 220 K and 370 K by a calorimetric technique. The original feature of this determination of capacitor losses lies in the use of the isothermal calorimetry and in the measurement of an electrical power and not of a temperature increase. The frequency dependence of the equivalent series resistance, at various temperatures, enables to separate the losses in the conducting material from those in the dielectric and to get their respective variations as a function of frequency and temperature. These variations of the equivalent series resistance with frequency at a given temperature have been reproduced by using an equivalent circuit composed of resistors, inductors and capacitors. This model has been verified for non-sinusoidal waveforms such as those met with in a filtering circuit and is used to evaluate by simulation the losses of the capacitor.

Seguin, B.; Gosse, J. P.; Ferrieux, J. P.

1999-12-01

41

Calorimetric thermobarometry of experimentally shocked quartz  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

42

Nanoclay modified polycarbonate blend nanocomposites: Calorimetric and mechanical properties  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

43

Unilateral NMR study of a XVI century wall painted.  

PubMed

Wall paintings in the XVI century Serra Chapel in the "Chiesa di Nostra Signora del Sacro Cuore" Rome, have been studied using unilateral NMR. In order to map the distribution of moisture content in the wall painted, a large number of Hahn echo measurements, covering large areas of the wall painting were performed. Because the intensity of the Hahn echo is proportional to the amount of moisture in the area under study, the experimental data were transformed into 2D gradient colour maps which allowed an easy visualization of the moisture content of the wall. The state of conservation of the wall painting was monitored using T2 measurements specially with regards to outcropping salt. PMID:17433740

Proietti, N; Capitani, D; Rossi, E; Cozzolino, S; Segre, A L

2007-06-01

44

An investigation of FeXVI emission lines in solar and stellar extreme-ultraviolet and soft X-ray spectra  

NASA Astrophysics Data System (ADS)

New fully relativistic calculations of radiative rates and electron impact excitation cross-sections for FeXVI are used to determine theoretical emission-line ratios applicable to the 251-361 and 32-77Å portions of the extreme-ultraviolet (EUV) and soft X-ray spectral regions, respectively. A comparison of the EUV results with observations from the Solar Extreme-Ultraviolet Research Telescope and Spectrograph (SERTS) reveals excellent agreement between theory and experiment. However, for emission lines in the 32-49Å portion of the soft X-ray spectral region, there are large discrepancies between theory and measurement for both a solar flare spectrum obtained with the X-Ray Spectrometer/Spectrograph Telescope (XSST) and for observations of Capella from the Low-Energy Transmission Grating Spectrometer (LETGS) on the Chandra X-ray Observatory. These are probably due to blending in the solar flare and Capella data from both first-order lines and from shorter wavelength transitions detected in second and third order. By contrast, there is very good agreement between our theoretical results and the XSST and LETGS observations in the 50-77Å wavelength range, contrary to previous results. In particular, there is no evidence that the FeXVI emission from the XSST flare arises from plasma at a much higher temperature than that expected for FeXVI in ionization equilibrium, as suggested by earlier work.

Keenan, F. P.; Drake, J. J.; Aggarwal, K. M.

2007-11-01

45

Calorimetric study of melts in the system KCl–K 2TaF 7  

Microsoft Academic Search

Enthalpy increment measurements on melts in the system KCl–K2TaF7 were carried out by drop calorimetry at temperatures between 298 and 1053, 1093 and 1133K and selected compositions. The heat capacities of melted mixtures and enthalpies of mixing were determined using the experimental data. Calorimetric experiments showed nonideality of the melts in several properties. The molar relative enthalpy and molar heat

I. Nerád; E. Mikšíková

2010-01-01

46

A calorimetric study of fatigue induced microstructural changes in aluminum alloy 7050  

Microsoft Academic Search

Differential scanning calorimetry (DSC) was used to detect microstructural changes resulting from strain-controlled fatigue of aluminum alloy 7050. Two starting conditions were investigated: a GP zone T6X temper and an overaged T73651. The calorimetric signature of the microstructure was determined for samples that had been cycled either to failure or to preselected percentages of their expected lifetime at various strain

J. M. Papazian; R. J. Deiasi; P. N. Adler

1980-01-01

47

A calorimetric study of fatigue induced microstructural changes in aluminum alloy 7050  

Microsoft Academic Search

Differential scanning calorimetry (DSC) was used to detect microstructural changes resulting from strain-controlled fatigue\\u000a of aluminum alloy 7050. Two starting conditions were investigated: a GP zone T6X temper and an overaged T73651. The calorimetric\\u000a signature of the microstructure was determined for samples that had been cycled either to failure or to preselected percentages\\u000a of their expected lifetime at various strain

J. M. Papazian; R. J. DeIasi; P. N. Adler

1980-01-01

48

Calorimetric studies of solid wastes, sewage sludge, wastewaters and their effects on soil biodegradation processes  

Microsoft Academic Search

Calorimetric studies of solid wastes, sewage sludge, wastewaters and their environmental effects focus on three main research\\u000a areas. The first research area involves determination of selected thermal and physical parameters characterizing the above\\u000a substances, such as specific heat, thermal conductivity and others. The second area covers processes of total or gradual destruction\\u000a of the examined substances at a fixed composition

J. Dziejowski; I. Bia?obrzewski

2011-01-01

49

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

NASA Technical Reports Server (NTRS)

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

Kauder, Lonny R.

2008-01-01

50

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

51

A calorimetric study of fatigue induced microstructural changes in aluminum alloy 7050  

NASA Astrophysics Data System (ADS)

Differential scanning calorimetry (DSC) was used to detect microstructural changes resulting from strain-controlled fatigue of aluminum alloy 7050. Two starting conditions were investigated: a GP zone T6X temper and an overaged T73651. The calorimetric signature of the microstructure was determined for samples that had been cycled either to failure or to preselected percentages of their expected lifetime at various strain amplitudes. Thermodynamic and kinetic analyses of the calorimetric results revealed a pronounced effect of plastic strain during fatigue on the reaction enthalpy and reaction kinetics of the GP zone dissolution peak of T6X, and a lesser effect on the ?' dissolution peak of T73651. No microstructural changes after fatigue to failure in the nominally elastic strain regime were detected by DSC. The calorimetric results were uniform throughout the cross-section of the fatigue specimens. Based upon these results, it is concluded that approximately 75 pct of the GP zones initially present can be affected during low cycle fatigue, and that overaging of the GP zone microstructure does not occur. The results from the T73651 temper show that low cycle fatigue affects this overaged microstructure in a different manner. Reversion or disordering of ?' does not occur, but some overaging was detected. It is suggested that the ?' precipitate in this alloy is not shearable.

Papazian, J. M.; Deiasi, R. J.; Adler, P. N.

1980-12-01

52

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

53

Calorimetric study of aligned liquid crystal + aerosil  

NASA Astrophysics Data System (ADS)

A high-resolution ac-calorimetric study was performed on magnetically aligned colloidal dispersions of 8CB and aerosil spanning the weakly first-order I-N and second order N-SmA phase transitions. Stable aligned samples were prepared by repeated cycling between the isotropic and nematic phase in the presence of a 2 T magnetic field. Zero-field measurements were carried out on six aligned conjugate density samples ranging from 0.03 to 0.15 g cm-3 (mass of aerosil per volume of liquid crystal). For comparison, two unaligned samples from the same batch (0.05 and 0.13 g cm-3) were also studied. The unaligned samples reproduce very closely previous studies on this system. The magnetically aligned samples, exhibits lower transition temperatures for the same aerosil density sample and a shift to higher aerosil density of the non-monotonic Tc evolution. The clear differences between aligned and unaligned sample indicate the ``memory'' of the magnetic field even after heating deep into the isotropic phase. The origin of this ``memory'' remains unexplained.

Cruceanu, F.; Iannacchione, G. S.; Liang, D.; Leheny, R. L.

2006-03-01

54

Calorimetric and relaxation properties of xylitol-water mixtures  

NASA Astrophysics Data System (ADS)

We present the first broadband dielectric spectroscopy (BDS) and differential scanning calorimetry study of supercooled xylitol-water mixtures in the whole concentration range and in wide frequency (10-2-106 Hz) and temperature (120-365 K) ranges. The calorimetric glass transition, Tg, decreases from 247 K for pure xylitol to about 181 K at a water concentration of approximately 37 wt. %. At water concentrations in the range 29-35 wt. % a plentiful calorimetric behaviour is observed. In addition to the glass transition, almost simultaneous crystallization and melting events occurring around 230-240 K. At higher water concentrations ice is formed during cooling and the glass transition temperature increases to a steady value of about 200 K for all higher water concentrations. This Tg corresponds to an unfrozen xylitol-water solution containing 20 wt. % water. In addition to the true glass transition we also observed a glass transition-like feature at 220 K for all the ice containing samples. However, this feature is more likely due to ice dissolution [A. Inaba and O. Andersson, Thermochim. Acta, 461, 44 (2007)]. In the case of the BDS measurements the presence of water clearly has an effect on both the cooperative ?-relaxation and the secondary ?-relaxation. The ?-relaxation shows a non-Arrhenius temperature dependence and becomes faster with increasing concentration of water. The fragility of the solutions, determined by the temperature dependence of the ?-relaxation close to the dynamic glass transition, decreases with increasing water content up to about 26 wt. % water, where ice starts to form. This decrease in fragility with increasing water content is most likely caused by the increasing density of hydrogen bonds, forming a network-like structure in the deeply supercooled regime. The intensity of the secondary ?-relaxation of xylitol decreases noticeably already at a water content of 2 wt. %, and at a water content above 5 wt. % it has been replaced by a considerably stronger water (w) relaxation at about the same frequency. However, the similarities in time scale and activation energy between the w-relaxation and the ?-relaxation of xylitol at water contents below 13 wt. % suggest that the w-relaxation is governed, in some way, by the ?-relaxation of xylitol, since clusters of water molecules are rare at these water concentrations. At higher water concentrations the intensity and relaxation rate of the w-relaxation increase rapidly with increasing water content (up to the concentration where ice starts to form), most likely due to a rapid increase of small water clusters where an increasing number of water molecules interacting with other water molecules.

Elamin, Khalid; Sjöström, Johan; Jansson, Helén; Swenson, Jan

2012-03-01

55

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

56

Electron impact excitation rates for transitions in beryllium-like P XII, S XIII, Cl XIV, Ar XV and K XVI  

NASA Astrophysics Data System (ADS)

The R-matrix electron excitation rates determined by Berrington et al. (1985) for C III, O V, Ne VII, and Si XI and by Dufton et al. (1983) for Ca XVII are used to interpolate the rates for Be-like P XII, S XIII, Cl XIV, Ar XV, and K XVI. The results are presented in a series of tables and briefly characterized. The accuracy of the present findings is estimated as + or - 10 percent within 0.8 dex of log Tmax, where Tmax is the temperature of maximum fractional abundance for ionization equilibrium. The applicability of the results to the diagnostics of astrophysical and laboratory plasmas is indicated.

Keenan, F. P.

1988-01-01

57

TECHNICAL DESIGN NOTE A differential formulation of the T-History calorimetric method  

NASA Astrophysics Data System (ADS)

We present a differential formulation of the T-History calorimetric method in order to achieve thermodynamic consistency with phase transitions theory and to include the important experimental effect of the speed of the thermal process in calorimetric calculations. To illustrate the applicability of the new formulation, we show some numerical results which give an acceptable description of calorimetric measures.

Moreno-Alvarez, L.; Herrera, J. N.; Meneses-Fabian, C.

2010-12-01

58

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.

59

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

60

A Temporal Map in Geostationary Orbit: The Cover Etching on the EchoStar XVI Artifact  

NASA Astrophysics Data System (ADS)

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.; Paglen, Trevor

2012-10-01

61

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

62

Calorimetric determination of enthalpy changes for the proton ionization of 3-[N-morpholino]propanesulfonic acid (MOPS), 4-[N-morpholino]butanesulfonic acid (MOBS) and 3-[N-morpholino]-2-hydroxypropanesulfonic acid (MOPSO) in water–methanol mixtures  

Microsoft Academic Search

Proton ionization enthalpies for three structurally related biological buffers, each with two ionizable protons, were determined using solution calorimetry. These buffers are 3-[N-morpholino]propanesulfonic acid (MOPS), 4-[N-morpholino]butanesulfonic acid (MOBS) and 3-[N-morpholino]-2-hydroxypropanesulfonic acid (MOPSO). Enthalpies were obtained in water–methanol mixtures with methanol mole fraction (Xm) from 0 to 0.360. The first ionization enthalpy (?H1) of all buffers was small (±1.2kJmol?1) at all

F. H. Jumean; N. M. Abdo; M. I. Khamis

2011-01-01

63

Calorimetric Method of Sensitivity Calibration for Far-Infrared Detectors.  

National Technical Information Service (NTIS)

A calorimetric method for measuring the absolute spectral sensitivity of a far-infrared (100 micrometers to 5 mm) detector was developed. The method uses a liquid-helium-cooled integrating-sphere calorimeter capable of measuring a radiative power of the o...

M. Daehler

1976-01-01

64

Thermodynamic properties of chlorite and berthierine derived from calorimetric measurements  

NASA Astrophysics Data System (ADS)

In the context of the deep waste disposal, we have investigated the respective stabilities of two iron-bearing clay minerals: berthierine ISGS from Illinois [USA; (Al0.975FeIII0.182FeII1.422Mg0.157Li0.035Mn0.002)(Si1.332Al0.668)O5(OH)4] and chlorite CCa-2 from Flagstaff Hill, California [USA; (Si2.633Al1.367)(Al1.116FeIII0.215Mg2.952FeII1.712Mn0.012Ca0.011)O10(OH)8]. For berthierine, the complete thermodynamic dataset was determined at 1 bar and from 2 to 310 K, using calorimetric methods. The standard enthalpies of formation were obtained by solution-reaction calorimetry at 298.15 K, and the heat capacities were measured by heat-pulse calorimetry. For chlorite, the standard enthalpy of formation is measured by solution-reaction calorimetry at 298.15 K. This is completing the entropy and heat capacity obtained previously by Gailhanou et al. (Geochim Cosmochim Acta 73:4738-4749, 2009) between 2 and 520 K, by using low-temperature adiabatic calorimetry and differential scanning calorimetry. For both minerals, the standard entropies and the Gibbs free energies of formation at 298.15 K were then calculated. An assessment of the measured properties could be carried out with respect to literature data. Eventually, the thermodynamic dataset allowed realizing theoretical calculations concerning the berthierine to chlorite transition. The latter showed that, from a thermodynamic viewpoint, the main factor controlling this transition is probably the composition of the berthierine and chlorite minerals and the nature of the secondary minerals rather than temperature.

Blanc, Philippe; Gailhanou, Hélène; Rogez, Jacques; Mikaelian, Georges; Kawaji, Hitoshi; Warmont, Fabienne; Gaboreau, Stéphane; Grangeon, Sylvain; Grenèche, Jean-Marc; Vieillard, Philippe; Fialips, Claire I.; Giffaut, Eric; Gaucher, Eric C.; Claret, F.

2014-05-01

65

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

Federal Register 2010, 2011, 2012, 2013

...SSA-2012-0071] Social Security Ruling, SSR 13-1p; Titles II and XVI: Agency Processes for Addressing Allegations of Unfairness, Prejudice, Partiality, Bias, Misconduct, or Discrimination by Administrative Law Judges (ALJs); Correction AGENCY: Social...

2013-02-12

66

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

Code of Federal Regulations, 2013 CFR

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

2013-04-01

67

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

68

Molecular energetics of alkyl pyrrolecarboxylates: calorimetric and computational study.  

PubMed

The pyrrole subunit plays an important role in material science as the building block of polypyrroles, an important representative class of conducting polymers, which found widely applications in the area of new materials due to their chemical, thermal, and electrical properties associated with their easiness and low cost of production, making them especially promising for commercial applications. The energetic characterization of this kind of molecules provides information concerning stability, reactivity, and biodegrability of chemical compounds in environment being, for example, helpful in choosing the most adequate method for their elimination by converting the waste into harmless compounds or even decreasing the production of toxic substances in industrial processes. This work reports a combination of calorimetric and computational determinations of several alkyl pyrrolecarboxylates (alkyl = methyl or ethyl) whose main purpose is the calculation of their standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, at T = 298.15 K. Experimentally, for methyl 1-pyrrolecarboxylate (M1PC), methyl 2-pyrrolecarboxylate (M2PC), and ethyl 2-pyrrolecarboxylate (E2PC), these values were derived from the standard (p° = 0.1 MPa) molar enthalpies of formation, in the condensed phase, ?fHm° (cr,l), at T = 298.15 K, obtained by static bomb combustion calorimetry, and from the standard molar enthalpies of phase transition, ?cr,l(g)Hm°, at T = 298.15 K, determined by high-temperature Calvet microcalorimetry. Standard ab initio molecular calculations, at the G3(MP2)//B3LYP level, were performed, and the standard enthalpies of formation of these three compounds were estimated. A very good agreement between the calculated and the experimental data was obtained. Thereby, we have extended these calculations to other alkyl pyrrolecarboxylates, namely, ethyl 1-pyrrolecarboxylate (E1PC), methyl 3-pyrrolecarboxylate (M3PC), and ethyl 3-pyrrolecarboxylate (E3PC), whose study was not performed experimentally. The computational analysis, at the B3LYP/6-31G(d) level of theory, of the six molecules allowed a detailed inspection and a better knowledge about their molecular structure and geometrical parameters. PMID:23682652

Santos, Ana Filipa L O M; Ribeiro da Silva, Manuel A V

2013-06-20

69

UV and soft X-ray lines from Fe XVI observed in solar and stellar spectra  

Microsoft Academic Search

The ion Fe XVI is abundant in solar active regions and flares. Strong spectral lines from this ion have been observed over a wide wavelength range. The transitions 3s-3p and 3p-3d fall between 250 and 365Å and lines from transitions between n=3 to n=4, n=3 to n=5 fall between 30 and 80Å. In this paper, we present distorted wave results

M. Cornille; J. Dubau; H. E. Mason; C. Blancard; W. A. Brown

1997-01-01

70

On board LIBS analysis of marine sediments collected during the XVI Italian campaign in Antarctica  

Microsoft Academic Search

The Laser-induced Breakdown Spectroscopy technique was applied on board the R\\/V Italica during the XVI Antarctic campaign (2000–2001) to carry out elemental chemical analysis of marine sediments collected using different sampling systems. To this end, a compact system has been built, which was suitable to operate also in the presence of mechanical vibrations, induced by the ship motion. Qualitative and

R. Barbini; F Colao; V Lazic; R Fantoni; A Palucci; M Angelone

2002-01-01

71

ELECTROCHEMICAL CALORIMETRIC STUDIES OF THE COLD FUSION EFFECT  

Microsoft Academic Search

Several types of calorimetric cell designs were used in attempts to measure excess enthalpy during the electrolysis of LiOD\\/D2O using palladium cathodes. Control experiments were run by using light water in place of D2O or by using platinum cathodes in place of palladium. Initial experiments using thin palladium cathodes of an unknown purity gave no significant differences between the Pd\\/D2O

M. H. Miles; D. E. Stilwell

72

Energy associated with dislocations: A calorimetric study using synthetic quartz  

Microsoft Academic Search

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,

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

1995-01-01

73

A Calorimetric Micro-Sensor for Methane Detection  

Microsoft Academic Search

In this work, a miniaturized pellistor for methane detection based on conventional IC fabrication is proposed and analysed. This integrated device should have several advantages over the standard design i.e. increased reproducibility, possibility to integrate read-out electronics on the same chip, reduced power consumption and possibility of making portable devices. The calorimetric sensor consists of a Ti-W heater (working temperature

Sebastian Sosin; Carmen Moldovan; Elena Manea

74

The Iron Project and the RMAX Project: Transitions in Fe XV, Fe XVI, and Astrophysical Applications  

NASA Astrophysics Data System (ADS)

While the Iron Project is involved in scattering and radiative atomic processes of iron and iron-peak elements, the Rmax Project aims at the X-ray spectroscopy of astrophysical objects. Under the Iron Project, the oscillator strengths and radiative decay rates for fine structure transitions going up to n=10 and l=9 are obtained for magenesium like Fe XV and sodium like Fe XVI. They correspond to 98 levels for Fe XVI and 504 levels for Fe XV. We have employed relativistic Breit-Pauli R-matrix method for the allowed electric dipole (E1) transitions and Breit-Pauli atomic structure calculations for forbidden (E2, E3, M1, M2) transitions for these ions. The results have been benchmarked against the ab initio coupled cluster method which includes relativistic effects. Very good agreement is found for Fe XVI. The application of the Iron Project and the RmaX Project data to laboratory and astrophysical sources is demonstrated for time-resolved spectroscopy of X-ray lines of He-like Fe and Ni, especially for the astrophysical diagnostic lines.

Montenegro, Maximiliano; Nahar, Sultana; Pradhan, Anil; Sur, Chiranjib; Oelgoetz, Justin

2007-06-01

75

The Iron Project and the RMAX Project: Transitions in Fe XV, Fe XVI, and Astrophysical Applications  

NASA Astrophysics Data System (ADS)

While the Iron Project is involved in scattering and radiative atomic processes of iron and iron-peak elements, the Rmax Project aims at the X-ray spectroscopy of astrophysical objects. Under the Iron Project, the oscillator strengths and radiative decay rates for fine structure transitions going up to n=10 and l=9 are obtained for magenesium like Fe XV and sodium like Fe XVI. They correspond to 98 levels for Fe XVI and 504 levels for Fe XV. We have employed relativistic Breit-Pauli R-matrix method for the allowed electric dipole (E1) transitions and Breit-Pauli atomic structure calculations for forbidden (E2, E3, M1, M2) transitions for these ions. The results have been benchmarked against the ab initio coupled cluster method which includes relativistic effects. Very good agreement is found for Fe XVI. The application of the Iron Project and the RmaX Project data to laboratory and astrophysical sources is demonstrated for time-resolved spectroscopy of X-ray lines of He-like Fe and Ni, especially for the astrophysical diagnostic lines.

Montenegro, Maximiliano; Nahar, Sultana; Pradhan, Anil; Sur, Chiranjib; Oelgoetz, Justin

2007-04-01

76

Theoretical Wavelengths of Fe XVI L-shell Transitions and Comparison with Laboratory Measurements and Chandra Observations of Capella  

NASA Astrophysics Data System (ADS)

We have used the relativistic multi-reference Møller-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 Å. This wavelength is within 0.0042 Å 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.; Diaz, F.; Ishikawa, Y.

2012-02-01

77

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

78

Calorimetric Studies on Sulphur Containing Compounds.  

National Technical Information Service (NTIS)

Heats of combustion of seven sulphur containing compounds have been determined using an oxygen bomb calorimeter, adiabatic-type. The data have been used to compute the respective heats of formation at 298 + or - 1 K and the energies of resonance and hydro...

M. Safdar

1984-01-01

79

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

80

Calorimetric studies of curium complexation. 2. Amino carboxylates  

SciTech Connect

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 of Cm(III) are greater than those for Eu(III). However, the entropy values for the complexing of both cations are similar. These results are comparable to the previously reported data for EDTA. 13 references, 2 figures, 3 tables.

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

1987-07-15

81

A calorimetric study on interactions of colchicine with human serum albumin  

NASA Astrophysics Data System (ADS)

Interaction of colchicine (COL) with human serum albumin (HSA) in buffer solutions (pH 7.2) has been investigated by isothermal titration calorimetry (ITC) combined with circular dichroism (CD) and UV-vis spectra. Heats of the interactions have been determined at 298.15 K. Based on the calorimetric data and reasonable suppositions for the bio-macromolecule - ligand binding process, the equilibrium constants, standard changes of enthalpy, entropy and Gibbs free energy of the processes are obtained. The results show that there are two classes of ligand binding sites. The first-class binding is mainly driven by entropy, while the second-class binding is synergistically driven by entropy and enthalpy. Circular dichroism (CD) and UV-vis spectra show that COL can change the secondary structure of HSA molecule.

Zhao, Qiang; Xu, Xiang-Yu; Sun, Xiang-Jun; Liu, Min; Sun, De-Zhi; Li, Lin-Wei

2009-08-01

82

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

83

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

84

Calorimetric investigations on the effect of position of functional groups on surfactant adsorption  

SciTech Connect

The effect of the positions of sulfonate and of methyl groups on the aromatic ring of isomerically pure alkylxylenesulfonates on their adsorption investigated in this study using microcalorimetry and electrokinetic measurements is found to be marked. It was observed that the position of the sulfonate with respect to the alkyl chain is more critical than that of the methyl groups in determining the adsorption behavior. The surfactant with the sulfonate in the para position with respect to the alkyl chain adsorbed more than that with the sulfonate in the meta position. Steric constraint to the packing of the molecules is proposed to be the main reason for the differences in the adsorption of these surfactants. Zeta potential measurements showed no difference in the charge characteristics of the surfactants. Calorimetric results suggest enthalpy to be the main driving force for adsorption at low surfactant concentrations while the adsorption is entropy driven at higher surfactant concentrations.

Sivakumar, A.; Somasundaran, P. (Columbia Univ., New York, NY (United States). Langmuir Center for Colloids and Interfaces); Thach, S. (ARCO Exploration and Technology Co., Plano, TX (United States))

1993-09-01

85

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

86

A paper-based calorimetric microfluidics platform for bio-chemical sensing.  

PubMed

In this report, a paper-based micro-calorimetric biochemical detection method is presented. Calorimetric detection of biochemical reactions is demonstrated as an extension of current colorimetric and electrochemical detection mechanisms of paper-based biochemical analytical systems. Reaction and/or binding temperature of glucose/glucose oxidase, DNA/hydrogen peroxide, and biotin/streptavidin, are measured by the paper-based micro-calorimeter. Commercially available glucose calibration samples of 0.05, 0.15 and 0.3% wt/vol concentration are used for comparing the device performance with a commercially available glucose meter (electrochemical detection). The calorimetric glucose detection demonstrates a measurement error less than 2%. The calorimetric detection results of DNA concentrations from 0.9 to 7.3mg/mL and temperature changes in biotin and streptavidin reaction are presented to demonstrate the feasibility of integrating the calorimetric detection method with paper based microfluidic devices. PMID:24713542

Davaji, Benyamin; Lee, Chung Hoon

2014-09-15

87

Empirical free energy calculation: comparison to calorimetric data.  

PubMed Central

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

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

1997-01-01

88

Calorimetric calibration of head coil SAR estimates displayed on a clinical MR scanner  

NASA Astrophysics Data System (ADS)

Calorimetric measurements were performed to determine the average specific absorption rates (SAR) resulting from MRI head examinations. The data were compared with average head coil SAR estimates displayed by the MR scanner in order to refine the imaging protocols used in imaging patients with implanted deep brain stimulators (DBS). The experiments were performed using transmit-receive (TR) head coil on clinical 1.5 T General Electric MR scanners running 11.0 M4 revision software. The average applied SAR was derived from temperature increases measured inside a head phantom, due to deposition of RF energy during MRI scanning with a spin echo imaging sequence. The measurements were repeated for varied levels of RF transmit gain (TG) and analyzed with a range of entered patient weights. The measurements demonstrate that the ratio of the actual average head SAR to the scanner-displayed value (coil correction factor) decreases for decreasing TG or for increasing patient weight and may vary between 0.3 and 2.1. An additional retrospective patient study, however, shows that not all combinations of TG and patient weight are encountered clinically and, instead, TG generally increases with the patient weight. As a result, a much narrower range of coil correction factors (e.g., typically 0.5-1.0) will be encountered in practice. The calorimetric method described in this work could aid the physicians and technologists in refinement of the model-dependent SAR estimates displayed by the MR scanner, and in selection of imaging parameters for MR head examinations within allowable SAR safety levels.

Gorny, Krzysztof R.; Bernstein, Matt A.; Felmlee, Joel P.; Ward, Heidi A.; McGee, Kiaran P.; Lanners, Diana M.; Lee, Kendall H.

2008-05-01

89

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

90

Fine-Structure Resolved Dielectronic Recombination Rates for the N = 3 Excited Configurations of Fe XVI--Fe XIX  

NASA Astrophysics Data System (ADS)

Spectroscopic analysis of X-ray emission lines from hot astrophysical plasmas, such as solar and cosmic X-ray sources, is a powerful tool in the determination of elemental abundances and temperature and density diagnostics of the emitting gas. This same analysis can be used to model high-temperature laboratory plasmas associated with magnetic and inertial confinement fusion as well as with the study of X-ray laser research. Accurate determination of atomic rates is crucial for a reliable analysis. Dielectronic recombination is the dominant recombination process for incompletely ionized plasmas. The rate coefficients for dielectronic recombination of several ionization stages of the astrophysically abundant element iron (Fe xvi-Fe xi x) are presented at the fine-structure levels of the n = 3 excited states at several temperatures. The rate coefficients are calculated for a Maxwellian electron distribution in a low-density corona approximation. The dielectronic recombination process involves a large number of doubly excited states of the recombined ions and computations of many radiative as well as autoionization rates from these states. In this calculation we include doubly excited states that are formed by the free electron captured up to very high Rydberg states and detailed calculations of all possible dipole allowed radiative transitions and all dipole as well as nondipole autoionization transitions. Transitions to excited states of the recombining ion from all open autoionization channels, which have a significant effect in reducing the rate coefficients (as presented in the works of Jacobs et al.), are also included in our calculations. These calculations were carried out in the isolated resonance approximation using the Hartree-Fock method with relativistic corrections (as described by Cowan). The dielectronic recombination rate coefficients were evaluated at many temperatures encompassing the range around the temperature of maximum abundance. These J-resolved data will be extremely useful for accurate ionization balance calculations for astrophysical as well as laboratory iron plasmas.

Dasgupta, Arati

1995-12-01

91

Descobrint el vulcanisme quaternari de la Garrotxa: De les observacions precientífiques als primers estudis geològics (s. XVI-XIX)  

Microsoft Academic Search

Una revisió crítica dels escrits anteriors a 1830 sobre la regió volcànica de la Garrotxa permet fer algunes precisions sobre el procés del descobriment i les primeres investigacions del vulcanisme quaternari de la comarca. Ja des del segle XVI es parlava d'unes suposades erupcions relacionades amb el terratrèmol de 1427 i s'havien descrit els productes del vulcanisme i les seves

Enric Aragonès i Valls

2007-01-01

92

Synthesis of nitrate sodalite: An in situ scanning calorimetric study  

NASA Astrophysics Data System (ADS)

The formation of nitrate sodalite, an important constituent of the resilient heels at DOE nuclear waste storage sites, was closely followed by oven synthesis, in situ calorimetry as a function of heating rate from 0.01 to 0.1 °C/min and X-ray diffraction. A transition sequence of amorphous-zeolite A-sodalite-cancrinite was confirmed. For in situ synthesis calorimetry, the heat flow peaks related to zeolite A formation are shifted to higher temperatures as heating rate increases. Although the end products are mostly nitrate sodalite, no calorimetric signals associated with zeolite A to sodalite conversion are detected. This suggests that the enthalpy of formation of zeolite A and sodalite are very similar and the zeolite A to sodalite conversion enthalpy is small. This conclusion is in accord with previous measurements by oxide melt solution calorimetry.

Liu, Qingyuan; Navrotsky, Alexandra

2007-04-01

93

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

94

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

National Technical Information Service (NTIS)

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 insen...

J. H. Klems G. O. Kelley

1995-01-01

95

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

96

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

97

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

98

Laser calorimetric absorptance testing of samples with varying geometry  

NASA Astrophysics Data System (ADS)

During the 1990s the International Standard for absorptance testing of optical coatings was developed. Based on the method of laser calorimetry and after years of theoretical and empirical work, ISO 115511 was revised and published in its current version in 2003. Laser calorimetry is based on the measurement and evaluation of the temperature increase caused by absorption in the sample exposed to laser radiation. In dependence on the thermal diffusivity of the sample, a temperature distribution develops in the irradiated sample. Therefore, finding a correlation of temperature increase and absorption becomes a complex task. This challenge was met by keeping the sample geometry to a standard size and simulating the thermal distribution for a number of optical materials. By this, LZH developed a calorimetric test set-up that offers fully calibrated absorptance values for sample diameters of 25 mm (or 1 inch) with a total error of below 13 % and a relative measurement error of below 5%. However, this technique is limited to the mentioned sample geometry. This work presents a new approach to adjust the measurement configuration to numerous sample sizes of standard circular laser components. Finite element analysis and experimental verification is presented for exemplary values of the samples diameters. Based on a new sample mount concept, this procedure allows utilizing all flexibility in test wavelength and angle of incidence, combined with the sensitivity level sufficient for current optical materials.

Balasa, I.; Jensen, L.; Ristau, D.

2013-11-01

99

Neutron induced capture and fission discrimination using calorimetric shape decomposition  

NASA Astrophysics Data System (ADS)

The neutron capture and fission cross-sections of 233U have been measured at the neutron time-of-flight facility n_TOF at CERN in the energy range from 1 eV to 1 keV using a high performance 4? BaF2 Total Absorption Calorimeter (TAC) as a detection device. In order to separate the contributions of neutron capture and neutron induced fission in the TAC, a methodology called Calorimetric Shape Decomposition (CSD) was developed. The CSD methodology is based on the study of the TAC's energy response for all competing reactions, allowing to discriminate between ? s originating from neutron induced fission and those from neutron capture reactions without the need for fission tagging or any additional detection system. In this article, the concept behind the CSD is explained in detail together with the necessary analysis to obtain the TAC's response to neutron capture and neutron induced fission. The discrimination between capture and fission contributions is shown for several neutron energies. A comparison between the 233U neutron capture and fission yield extraction with ENDF/B-VII v1. library data is also provided.

Carrapiço, C.; Berthoumieux, E.; Dridi, W.; Gonçalves, I. F.; Gunsing, F.; Lampoudis, C.; Vaz, P.; n TOF Collaboration

100

Calorimetric analysis of gelatine-glycosaminoglycans blend system.  

PubMed

Gelatine is one of the most valuable natural polymers used for drug delivery applications. Gelatine-GAGs based composite system has been shown to act as good scaffolds for tissue engineering. The objective of the present study is to investigate the calorimetric properties of microporous gelatine-GAGs based blend, which were modified by co-crosslinking with a naturally occurring crosslinking agent genipin. The melting temperature (T(m)), enthalpy change (?H(m)) and heat capacity change (?C(p)) were systematically calculated over the experimentally observed systems using differential scanning calorimeter (DSC). The thermoporometry results suggest that the concentration of the glycosaminoglycans plays an important role in the pore size distribution of the blend matrices. The circular dichroism (CD) spectroscopy study, scanning electron microscopy (SEM) studies provide the valuable information about the structural features of the biodegradable blend that can be utilized for various biomedical applications. The results provide new insights into the thermal stability of blend and suggest potential strategies for its manipulation. PMID:21600914

Kanungo, Ivy; Chellappa, Nisha; Fathima, N Nishad; Rao, J Raghava

2011-10-01

101

Differential scanning calorimetric studies of nickel titanium rotary endodontic instruments.  

PubMed

Differential scanning calorimetric (DSC) analyses were performed between -130 degrees and 100 degrees C on specimens prepared from nickel-titanium (NiTi) rotary endodontic instruments: ProFile (n = 5), Lightspeed (n = 4), and Quantec (n = 3). The ProFile and Lightspeed instruments were in the as-received condition, whereas the Quantec instruments were randomly selected from a dental clinic and had unknown history. The DSC plots showed that the ProFile and Lightspeed instruments analyzed had the superelastic NiTi property, with an austenite-finish (Af) temperature of approximately 25 degrees C. Differences in DSC plots for the ProFile instruments and the starting wire blanks (n = 2) were attributed to the manufacturing process. The phase transformation behavior when the specimens were heated and cooled between -130 degrees and 100 degrees C, the temperature ranges for the phase transformations, and the resulting enthalpy changes were similar to those previously reported for nickel-titanium orthodontic wires having superelastic characteristics or shape memory behavior in the oral environment. The experiments demonstrated that DSC is a powerful tool for materials characterization of these rotary instruments, providing direct information not readily available from other analytical techniques about the NiTi phases present, which are fundamentally responsible for their clinical behavior. PMID:12184415

Brantley, W A; Svec, T A; Iijima, M; Powers, J M; Grentzer, T H

2002-08-01

102

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

2013-03-10

103

Application of Calorimetric Low Temperature Detectors (CLTD's) for Precise Stopping Power Measurements of Heavy Ions in Matter  

NASA Astrophysics Data System (ADS)

Calorimetric low temperature detectors (CLTD's) have been included in a B-ToF setup, that has already been used several times to perform energy loss measurements at the accelerator laboratory of the University of Jyväskylä. The new experimental setup enabled a precise determination of stopping power data for 0.05-1 MeV/u ^{131} Xe ions in carbon, nickel and gold. The results are presented and compared to data from literature and theoretical predictions. As a by-product, due to the excellent energy resolution of CLTD's for heavy ions at low energies, an observation of channeling effects in very thin polycrystalline targets and a determination of the channeling energy loss for 0.1-0.5 MeV/u ^{131} Xe-ions in Ni- and Au-absorbers was possible.

Echler, A.; Egelhof, P.; Grabitz, P.; Kettunen, H.; Kraft-Bermuth, S.; Laitinen, M.; Müller, K.; Rossi, M.; Trzaska, W. H.; Virtanen, A.

2014-01-01

104

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

PubMed

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 exothermic behavior and self-accelerating decomposition in the laboratory. In essence, methyl ethyl ketone peroxide (MEKPO) is highly reactive and exothermically unstable. In recent years, it has undergone many thermal explosions and runaway reaction incidents in the manufacturing process. Differential scanning calorimetry (DSC), vent sizing package 2 (VSP2), and thermal activity monitor (TAM) were employed to analyze thermokinetic parameters and safety index. The intent of the analyses was to facilitate the use of various auto-alarm equipments to detect over-pressure, over-temperature, and hazardous materials leaks for a wide spectrum of operations. Results indicated that MEKPO decomposition is detected at low temperatures (30-40 degrees C), and the rate of decomposition was shown to exponentially increase with temperature and pressure. Determining time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), maximum temperature (T(max)), exothermic onset temperature (T(0)), and heat of decomposition (DeltaH(d)) was essential for identifying early-stage runaway reactions effectively for industries. PMID:19619941

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

2009-11-15

105

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

SciTech Connect

A model for phase equilibria of coal derived liquids is to be extended to include calorimetric properties as well. To accomplish this satisfactorily, the proposed work includes three tasks (1) Refinement of the characterization procedure to include distribution of sulfur, oxygen, and nitrogen heteroatoms in coal liquids; (2) Measurement of high temperature (upto 400 C) and high pressure (upto 1000 psi) VLE data for binary systems of selected model compounds; and (3) Development of the thermodynamic model. Solutions have been found for the two problems encountered in the VLE apparatus. The equilibrium cell has been fitted with a new level sensing system. After extensive research, a substitute sealant material for the plug valves has been discovered. The work on chromatographic characterization of coal liquids is continuing. The Varex detector and the Gilson fraction collector have arrived and with that all the hardware necessary for the separation is available. The Perkin-Elmer PLGel 100 A, 5 micron column together with guard column and accessories, and THF solvent have been received. We are currently making calibration runs using PL-polymer standards with O-dichlorobenzene as an internal standard. Two analytical methods have been identified for specific analysis of the fractions. The main technique will be elemental analysis with a Perkin Elmer elemental analyzer. In addition, the functional groups and their composition in the sample will be determined using the Mattson Polaris FTIR spectrometer with a horizontal ATR sampler.

Kabadi, V.N.

1991-01-01

106

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

107

Effect of Heat Generation of Ultrasound Transducer on Ultrasonic Power Measured by Calorimetric Method  

NASA Astrophysics Data System (ADS)

Ultrasonic power is one of the key quantities closely related to the safety of medical ultrasonic equipment. An ultrasonic power standard is required for establishment of safety. Generally, an ultrasonic power standard below approximately 20 W is established by the radiation force balance (RFB) method as the most accurate measurement method. However, RFB is not suitable for high ultrasonic power because of thermal damage to the absorbing target. Consequently, an alternative method to RFB is required. We have been developing a measurement technique for high ultrasonic power by the calorimetric method. In this study, we examined the effect of heat generation of an ultrasound transducer on ultrasonic power measured by the calorimetric method. As a result, an excessively high ultrasonic power was measured owing to the effect of heat generation from internal loss in the transducer. A reference ultrasound transducer with low heat generation is required for a high ultrasonic power standard established by the calorimetric method.

Uchida, Takeyoshi; Kikuchi, Tsuneo

2013-07-01

108

75 FR 62676 - Disability Determinations by State Agency Disability Examiners  

Federal Register 2010, 2011, 2012, 2013

...Determinations by State Agency Disability Examiners AGENCY: Social Security Administration...II and XVI of the Social Security Act (Act...the approval of a State agency medical or...are also experts in Social Security disability...other opinions of State agency medical...

2010-10-13

109

Calorimetric behaviors of hydroxylamine and its salts caused by Fe(III)  

Microsoft Academic Search

The objective of this study is to obtain information on the calorimetric behaviors of aqueous solutions of hydroxylamine (HA), hydroxylamine chloride (HACl), and hydroxylamine nitrate(HAN) caused by different Fe(III) states (free Fe(III) from Fe(NH4)(SO4)2, Fe(CN)63?, and Fe(EDTA)?). The calorimetric data were obtained with a small-scaled reaction calorimeter, Super-CRC.In the mixing with Fe(III), HA showed the highest reactivity among three substrates.

Mieko Kumasaki; Yasuhiro Fujimoto; Takayuki Ando

2003-01-01

110

Calorimetric Measurement of Negative Surface Energy in Superconductors of the Second Kind.  

National Technical Information Service (NTIS)

The experimental details of this study are covered in the Ph.D. Thesis of Robert R. Riche entitled: 'A Calorimetric Study of the Effects of Surface Energy in a type II Superconductor.' The entropy of the mixed state of type II superconductors has been inv...

D. C. Hopkins

1968-01-01

111

Detection of dichlorvos residue by flow injection calorimetric biosensor based on immobilized chicken liver esterase  

Microsoft Academic Search

A flow injection calorimetric biosensor for dichlorvos residue detection is developed. This biosensor consists of a peristaltic pump, an injection valve, a thermoelectric thermostat, two cells (an enzyme reaction cell and a reference cell), a thermopile sensor and a computer. The reaction temperature of mix solution is stabilized at 40°C by the thermostat when the solution is pumped by the

Yi-Hua Zheng; Tse-Chao Hua; Da-Wen Sun; Jian-Jun Xiao; Fei Xu; Fang-Fang Wang

2006-01-01

112

A Differential Scanning Calorimetric Study of Newcastle Disease Virus: Identification of Proteins Involved in Thermal Transitions  

Microsoft Academic Search

The irreversible thermal denaturation of Newcastle disease virus was investigated using different techniques including high-sensitivity differential scanning calorimetry, thermal gel analysis intrinsic fluorescence, and neuraminidase activity assays. Application of a successive annealing procedure to the scanning calorimetric endotherm of Newcastle disease virus furnished four elementary thermal transitions below the overall endotherm; these were further identified as coming from the denaturation

Valery L. Shnyrov; Galina G. Zhadan; César Cobaleda; Ana Sagrera; Isabel Muñoz-Barroso; Enrique Villar

1997-01-01

113

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

Microsoft Academic Search

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

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

1991-01-01

114

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

Microsoft Academic Search

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

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

1991-01-01

115

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

116

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

117

A calorimetric technique for measuring total emissivity of solid materials and coatings at low temperatures  

Microsoft Academic Search

A calorimetric method for measuring total emissivity of solid materials and coatings at low temperatures is reported. This method has the advantage of greater rapidity in taking data, and allows one to perform measurements on samples nearly in thermal equilibrium. Moreover, by recording the thermal expansion of the foil, rather than measuring its temperature directly, some of the systematic errors

D. Giulietti; A. Gozzini; M. Lucchesi; R. Stampacchia

1979-01-01

118

Micro-calorimetric sensor for vapor phase explosive detection with optimized heat profile  

Microsoft Academic Search

A heater design, used in a micro-calorimetric sensor, has been optimized for temperature uniformity in order to increase the sensitivity and reliability of detection of trace amounts of explosives. In this abstract the design, fabrication and characterization is described. The performance of the novel heater design is characterized by measuring the temperature coefficient of resistivity (TCR) values and by mapping

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

2010-01-01

119

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

National Technical Information Service (NTIS)

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...

V. N. Kabadi

1992-01-01

120

Observation of nuclear recoil events from neutron scattering in low temperature calorimetric detectors  

Microsoft Academic Search

Energy spectra are obtained for low temperature calorimetric detectors exposed to a neutron source to produce nuclear recoil events simulating those which would occur in a ``dark matter'' detector. The targets used were a 4 g Si crystal and a 32 g LiF crystal, fitted with Ge temperature sensors to observe the particle scattering events as thermal pulses at a

P. F. Smith; G. J. Homer; S. F. J. Read; D. J. White; J. D. Lewin; N. J. C. Spooner

1991-01-01

121

The multidomain structure of ceruloplasmin from calorimetric and limited proteolysis studies.  

PubMed

Differential scanning calorimetry has been used to investigate the thermal stability of three different ceruloplasmins (from sheep, chicken, and turtle) in their native state and after limited proteolysis. The three undegraded proteins showed a similar structural organization in three calorimetric domains, although their temperature of unfolding varied from 57.8 degrees C (turtle) to 71.2 degrees C (sheep) to 82.1 degrees C (chicken). The spectroscopic and the catalytic properties were totally lost at temperatures corresponding to the unfolding of the less thermostable domain in the case of sheep and chicken ceruloplasmins and to the unfolding of the most thermostable domain in the turtle protein. Trypsin, but not plasmin, digestion caused a significant decrease of the thermal stability of sheep and chicken ceruloplasmins. Turtle ceruloplasmin was insensitive to both proteases. Comparing the thermodynamic parameters of the sheep protein in its undegraded and cleaved states revealed a mismatch between the three calorimetric domains and the 3-fold internal replication of the primary structure, which is evident in the highly homologous, fully sequenced human protein. Copper removal caused the rearrangement of the molecule in only two calorimetric domains, suggesting a role of the metal atoms in organizing a new calorimetric domain, which was tentatively assigned to the less thermostable cooperative unit of the native protein. PMID:2250007

Bonaccorsi di Patti, M C; Musci, G; Giartosio, A; D'Alessio, S; Calabrese, L

1990-12-01

122

Design and simulations for a calorimetric micro-sensor for methane detection  

Microsoft Academic Search

This work consists of two sections: design and simulations of a calorimetric methane sensor. In the first part, the technology steps and the masks are presented. The sensor is built on a suspended membrane released using front side sacrificial etch or back side anisotropic etch. The sensitive element is a platinum temperature sensor covered with a layer of doped porous

S. Sosin; C. Moldovan; R. Iosub

2004-01-01

123

Calorimetrically measured enthalpies for the reaction of Hf with H(D){sub 2} (g)  

SciTech Connect

The enthalpy for the direct reaction of H{sub 2} (g) with Hf has been measured by calorimetry for the first time at both moderate, 334 K, and elevated, 919 K, temperatures. The enthalpy for the reaction: 1/2 H{sub 2} (g) + 1(b{minus}a)HfH{sub a}({alpha}) {r_arrow} 1/(b{minus}a)HfH{sub b}({delta}) is {minus}70 {+-} 2.0 kJ/mol H at 334 K over a range of H contents from (H/Hf) = 0.5 to 1.5 with similar values found for D. The quantities {alpha} and {delta} are the coexisting phases and a and b are the corresponding (H/Hf) ratios, respectively. The magnitude of the enthalpy decreases from (H/Hf) = 0 to 0.5 and is then stable from 0.5 to 1.7. The value of {Delta}H{degree}{sub f} (HfH{sub 1.5}) = {minus}107.5 kJ/mol and {Delta}H{degree}{sub f} (HfH{sub 2.0}) = {minus}142.0 kJ/mol. In the elevated temperature range, calorimetric and equilibrium hydrogen pressure were determined over the range of H contents from 0 to 1.6. The enthalpy for the plateau reaction is {minus}74.5 kJ/mol H and after the two-phase region, {vert_bar}{Delta}H{sub H}{vert_bar} increases with the increase of (H/Hf) passing through a maximum at about (H/Hf) = 1.3.

Luo, W. [Univ. of Vermont, Burlington, VT (United States). Dept. of Chemistry]|[Duracell Worldwide Technology Center, Needham, MA (United States); Flanagan, T.B.; Clewley, J.D. [Univ. of Vermont, Burlington, VT (United States); Dantzer, P. [CNRS-URA, Orsay (France)

1993-12-01

124

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

125

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

126

Comparison of three gamma ray isotopic determination codes: FRAM, MGA, and TRIFID.  

National Technical Information Service (NTIS)

The determination of the isotopic distribution of plutonium and the americium concentration is required for the assay of nuclear material by calorimetry or neutron coincidence counting. The isotopic information is used in calorimetric assay to compute the...

T. L. Cremers J. E. Malcom C. A. Bonner

1994-01-01

127

Kinetics of Solid-State Reactions in Al-Li-Cu-Mg-Zr Alloys from Calorimetric Studies  

NASA Astrophysics Data System (ADS)

Differential scanning calorimetric (DSC) studies at different heating rates have been carried out to examine the solid-state reactions in 1441 and 8090 Al-Li-Cu-Mg-Zr alloys of water-quenched (WQ) and retrogressed tempers. The DSC peaks indicating the reactions sequence such as formation of GPB zones, precipitations of ?' phase, dissolution of GPB zones and ?' precipitates, and precipitations of S', T 1, T 2, and ? phases have been identified. From the heat flow associated with the peaks of the thermograms, the fraction transformation ( Y), the rate of transformation ( dY/ dt), the activation energy ( Q*), the frequency factor ( k 0), and the transformation function f( Y) for all the reactions of the 1441 and 8090 alloys have been determined. The appearance of separate peaks of GPB zone formation and ?' precipitation in the 1441 alloy of retrogressed tempers has enabled determination of the kinetic parameters, which is otherwise not possible from the thermograms of the WQ state due to peak overlapping, by varying heating rate method. The kinetic parameters determined from the DSC data of all the reactions of the alloys are in good agreement with the previously published data.

Ghosh, K. S.; Das, K.; Chatterjee, U. K.

2007-09-01

128

The Development of High-Resolution Calorimetric X-Ray Detectors for Compton Scattering Experiments  

Microsoft Academic Search

Compton scattering is a means of probing electron momentum distributions and can be used to evaluate calculations of electron wavefunctions in solids. The need for improved resolution in Compton experiments performed with high energy x-rays has motivated the development of a high resolution spectrometer. Calorimetric x-ray detectors, produced at Goddard Space Flight Center for x-rays around 6 KeV, have been

Caroline Kilbourne Stahle

1992-01-01

129

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

130

Calorimetric investigations on thermoregulation and growth of wax moth larvae Galleria mellonella  

Microsoft Academic Search

Laboratory cultures of larvae of the wax moth Galleria mellonella show drastically increased temperatures a few days after the start of cultures. To examine this phenomenon, we performed direct calorimetric measurements on isolated eggs and larvae of different larval stages. Fourth and fifth instar larvae have significantly increased mass-specific heat production rates (up to 160 mW g?1). These high heat

Erik Schmolz; Olaf Schulz

1995-01-01

131

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

Microsoft Academic Search

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

Teresa L Cremers; Thomas E Sampson

2010-01-01

132

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

133

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

134

Adsorption of arsenic ions on Brazilian sepiolite: effect of contact time, pH, concentration, and calorimetric investigation.  

PubMed

The original sepiolite clay mineral has been collected from Amazon region, Brazil. The compound 2-aminomethylpyridine (AMP) was anchored onto Amazon sepiolite surface by heterogeneous route. The natural (SPT) and modified (SPT(AMP)) sepiolite samples were characterized by elemental analysis, SEM, N(2) adsorption, and nuclear magnetic nuclei of (29)Si and (13)C. The well-defined peaks obtained in the (13)C NMR spectrum in the 0-160 ppm region confirmed the attachment of organic functional groups as pendant chains bonded into the porous clay. The ability of these materials to remove As(V) from aqueous solution was followed by a series of adsorption isotherms at room temperature and pH 4.0. The maximum number of moles adsorbed was determined to be 7.26×10(-2) and 11.70×10(-2) mmol g(-1) for SPT and SPT(AMP), respectively. In order to evaluate the clay samples as adsorbents in dynamic system, a glass column was fulfilled with clay samples (1.0 g) and it was fed with 2.0×10(-2) mmol dm(-3) As(V) at pH 4.0. The energetic effects caused by metal cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such As(V)-nitrogen interactions. PMID:20307889

Guerra, Denis L; Batista, Adriano C; da Costa, Paulo C Corrêa; Viana, Rúbia R; Airoldi, Claudio

2010-06-01

135

Development of a new type of high pressure calorimetric cell, mechanically agitated and equipped with a dynamic pressure control system: Application to the characterization of gas hydrates  

NASA Astrophysics Data System (ADS)

A novel prototype of calorimetric cell has been developed allowing experiments under pressure with an in situ agitation system and a dynamic control of the pressure inside the cell. The use of such a system opens a wide range of potential practical applications for determining properties of complex fluids in both pressurized and agitated conditions. The technical details of this prototype and its calibration procedure are described, and an application devoted to the determination of phase equilibrium and phase change enthalpy of gas hydrates is presented. Our results, obtained with a good precision and reproducibility, were found in fairly good agreement with those found in literature, illustrate the various interests to use this novel apparatus.

Plantier, F.; Marlin, L.; Missima, D.; Torré, J.-P.

2013-12-01

136

Development of a new type of high pressure calorimetric cell, mechanically agitated and equipped with a dynamic pressure control system: application to the characterization of gas hydrates.  

PubMed

A novel prototype of calorimetric cell has been developed allowing experiments under pressure with an in situ agitation system and a dynamic control of the pressure inside the cell. The use of such a system opens a wide range of potential practical applications for determining properties of complex fluids in both pressurized and agitated conditions. The technical details of this prototype and its calibration procedure are described, and an application devoted to the determination of phase equilibrium and phase change enthalpy of gas hydrates is presented. Our results, obtained with a good precision and reproducibility, were found in fairly good agreement with those found in literature, illustrate the various interests to use this novel apparatus. PMID:24387468

Plantier, F; Marlin, L; Missima, D; Torré, J-P

2013-12-01

137

Calorimetric evaluation of commercial Ni-MH cells and charges  

NASA Technical Reports Server (NTRS)

The test objectives are to evaluate the electrical and thermal performance of commercial Ni-MH cells and to evaluate the effectiveness of commercial charge control circuits. The ultimate design objectives are to determine which cell designs are most suitable for scale-up and to guide the design of future Shuttle and Station based battery chargers.

Darcy, Eric C.; Hughes, Brent M.

1995-01-01

138

Elastic and Irreversible Energies of a Two-Stage Martensitic Transformation in NiTi Utilizing Calorimetric Measurements  

NASA Astrophysics Data System (ADS)

Elastic energy and irreversible energy are quantified based on calorimetric measurements. We analyze energetics for each stage of the stress-free, thermally induced two-stage phase transformation A ? R ? B19' in an aged Ni-rich NiTi shape memory alloy. Heating/cooling rates are imposed from 1 K/min up to 100 K/min. We compare energetic analysis after multiple thermal cycles to virgin ( i.e., first-cycle) material. Fundamental thermodynamic formulations are applied from two perspectives: the free energy change d G, and the rate of change of free energy expressed as d G/d f m. Two measures of irreversible contributions are defined: the difference between the forward and reverse transformation heats, and the product of the entropy and the thermal hysteresis. Higher values are determined for the former. For scan rates of 10 K/min and greater, the energetic values become relatively stable. Substantial variations are evident at 1, 5, and 10 K/min. The scan rate impacts the elastic strain energy and irreversible energy of the B19' markedly compared with the R-phase transition. The findings are rationalized considering morphologic changes at the lower scan rates and the impacts on elastic and irreversible energies.

Lanba, Asheesh; Hamilton, Reginald F.

2014-06-01

139

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

140

Calorimetric study of polyethylene terephthalate)\\/poly(butylene terephthalate) blends  

Microsoft Academic Search

Poly(ethylene terephthalate)\\/poly(butylene terephthalate) blends [xPET\\/(l-x)PBT] were prepared by ultraquenching of the melt between two metal rolls rotating in a liquid nitrogen bath. Both DSC and WAXS studies indicate that immediately after preparation, the blends are amorphous regardless of the composition. Two glass transition temperatures are found for the as-quenched 0.5 PET\\/0.5 PBT blend. The activation energies determined from the dependence

I. Avramov; N. Avramova

1991-01-01

141

Calorimetric and emf studies on liquid Li-Sn alloys  

Microsoft Academic Search

By means of high temperature calorimetry the mixing enthalpies ?H of liquid Li-Sn alloys have been measured; however, due to experimental problems they were determined only forx\\u000a Li = 0.01 to 0.5 andx\\u000a Li = 0.87 to 0.99. The range of temperatures studied was 691 to 938 K. High compound forming tendency in Li-Sn is reflected\\u000a by a triangular-shaped relation

Zbigniew Moser; Wladyslaw Gasior; Ferdinand Sommer; Günter Schwitzgebel; Bruno Predel

1986-01-01

142

HIGH-ACCURACY MR-MP PERTURBATION THEORY ENERGY AND RADIATIVE RATES CALCULATIONS FOR CORE-EXCITED TRANSITIONS IN Fe XVI  

SciTech Connect

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 1s {sup 2}2s{sup k} 2p{sup m} 3l {sup p} nl' {sup 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.

Diaz, F.; Vilkas, M. J.; Ishikawa, Y. [Department of Chemistry and the Chemical Physics Program, University of Puerto Rico, P.O. Box 23346, San Juan, PR 00931-3346 (Puerto Rico); Beiersdorfer, P., E-mail: beiersdorfer1@llnl.gov [Physics Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

2013-07-01

143

Calorimetric investigation of deuterated palladium electrodes. Technical report, Apr-Sep 89  

SciTech Connect

Calorimetric experiments were conducted to verify the caloric claims by Fleischmann and Pons. A twin-cell heat conduction calorimeter was used, rather than the quasiadiabatic instrumentation of the original investigation. Under similar electrochemical conditions, the output of heat powers from experimental cells of Pd in 0.1 M LiOD/D2O and that from control cells of Pd in 0.1 M LiOH/H2O and Pt in 0.1 M LiOD/D2O were all in close agreement with input heat powers using simple theory. These results show no anomalous excess heat, as claimed.

Jow, T.R.; Slane, S.; Plichta, E.J.; Walker, C.W.; Gilman, S.

1991-05-01

144

Nanowell-patterned TiO2 microcantilevers for calorimetric chemical sensing  

NASA Astrophysics Data System (ADS)

A sensitive calorimetric sensor using a TiO2 microcantilever with nanowells patterned on one of its sides is described. This single material cantilever is sensitive to temperature change without relying on the metal deposition-based bimetallic effect. The thermomechanical sensitivity originates from the structure dependent variations in both the elastic modulus and thermal expansion coefficient due to the presence of ordered nanowells. These cantilever beams offer an alternate and efficient chemical sensing route for vapor phase analytes using photothermal spectroscopy. Selective and sensitive detection of organophosphorus compounds, as well as their photocatalytic decomposition under ultraviolet light exposure are demonstrated.

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

2014-04-01

145

Comment on "Binding of alkaloid harmalol to DNA: Photophysical and calorimetric approach".  

PubMed

The present manuscript is a comment on the article entitled "Binding of alkaloid harmalol to DNA: Photophysical and calorimetric approach" by Sarita Sarkar and Kakali Bhadra (2014) [1]. In their article, the authors reported the chemical structure as well as the absorption spectra of harmalol at different pH. On the bases of the previous publications and our own present results, the assignment of the number of the acid-base species and the corresponding pKa values, as well as the chemical structure for each species are erroneous. These facts have strong effect on the conclusions reached by the authors, in terms of the interaction with DNA. PMID:24836518

Alomar, Maria L; Micaela Gonzalez, M; Erra-Balsells, Rosa; Cabrerizo, Franco M

2014-07-01

146

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

Microsoft Academic Search

Calorimetric and fluorescence techniques were used to characterize the binding of aminoglycosides-neomycin, paromomycin, and ribostamycin, with 5?-dA12-x-dT12-x-dT12-3? 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 Tm for triplex decreases with increasing pH value in the presence of neomycin, while the Tm for the duplex remains unchanged. (2)

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

2010-01-01

147

Calorimetric study of blends of poly(butylene terephthalate) and liquid crystalline copolyester  

Microsoft Academic Search

A calorimetric study of blends of poly(ethylene terephthalate-co-p-oxybenzoate), PET\\/PHB, with poly(butylene terephthalate),\\u000a PBT has been carried out in the form of as-spun and drawn fibres. DSC melting and crystallization results show that PBT is\\u000a compatible with LCP and the crystallization of PBT decreases by the addition of LCP in the matrix. The crystallization behaviour\\u000a of blend fibres is investigated as

S. Mehta; B. L. Deopura

1993-01-01

148

A reaction calorimetric investigation of the hydrogenation of a substituted pyrazine  

SciTech Connect

Reaction calorimetry was the primary tool in investigations of the liquid-phase hydrogenation of a substituted pyrazine compound carried out over supported Pd catalysts. In addition to providing information about gas-liquid mass transfer limitations, calorimetric measurements provided a kinetic analysis of how product selectivity in this consecutive reaction network may be tuned by changing reaction conditions. Concentration profiles developed from fitting the heat flow data to a first-order model were compared with analytical measurements of concentration, demonstrating the utility of combining independent measurements of reaction progress as a means of assessing the validity of a kinetic model. 15 refs., 5 figs., 3 tabs.

Landau, R.N.; Singh, U.; Gortsema, F. [Merck & Company, Inc., Rahway, NJ (United States)] [and others] [Merck & Company, Inc., Rahway, NJ (United States); and others

1995-11-01

149

Calorimetric determination of thermal parameters of the Li\\/BrCl in SOCl2 (BCX) chemistry  

Microsoft Academic Search

The heat capacity of a Li-BCX DD-cell was found to be dependent on its state of charge by drop calorimetry measurements. The method of drop calorimetry involves measuring the energy (Joules) gained or lost from a sample that is transferred from a bath at temperature A to one at temperature B. The thermoneutral potential is defined as the cell potential

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

1990-01-01

150

Calorimetric determination of inhibition of ice crystal growth by antifreeze protein in hydroxyethyl starch solutions.  

PubMed Central

Differential scanning calorimetry and cryomicroscopy were used to investigate the effects of type I antifreeze protein (AFP) from winter flounder on 58% solutions of hydroxyethyl starch. The glass, devitrification, and melt transitions noted during rewarming were unaffected by 100 micrograms/ml AFP. Isothermal annealing experiments were undertaken to detect the effects of AFP-induced inhibition of ice crystal growth using calorimetry. A premelt endothermic peak was detected during warming after the annealing procedure. Increasing the duration or the temperature of the annealing for the temperature range from -28 and -18 degrees C resulted in a gradual increase in the enthalpy of the premelt endotherm. This transition was unaffected by 100 micrograms/ml AFP. Annealing between -18 and -10 degrees C resulted in a gradual decrease in the premelt peak enthalpy. This process was inhibited by 100 micrograms/ml AFP. Cryomicroscopic examination of the samples revealed that AFP inhibited ice recrystallization during isothermal annealing at -10 degrees C. Annealing at lower temperatures resulted in minimal ice recrystallization and no visible effect of AFP. Thus, the 100 micrograms/ml AFP to have a detectable influence on thermal events in the calorimeter, conditions must be used that result in significant ice growth without AFP and visible inhibition of this process by AFP. Images FIGURE 8

Hansen, T N; Carpenter, J F

1993-01-01

151

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

152

Calorimetric studies of freeze-induced dehydration of phospholipids.  

PubMed Central

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.

Bronshteyn, V L; Steponkus, P L

1993-01-01

153

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

154

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

PubMed

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

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

2014-01-01

155

Calorimetric method for measuring high ultrasonic power using water as a heating material  

NASA Astrophysics Data System (ADS)

The present study shows the calorimetric method for measuring high ultrasonic power using water as the heating material. In recent years, at the National Metrology Institute of Japan (NMIJ), an ultrasonic power primary standard of from 1 mW to 15 W has been established by the radiation force balance (RFB) method. Conventionally, the RFB method is widely used for ultrasonic power measurement, but this method is not suitable for very high power measurement due to thermal damages to the absorbing targets. High power ultrasonic standards, however, are being required by medical HITU measurements and in the sonochemistry industry. In order to meet these requirements, we have started to develop an ultrasonic power standard between 15 W and 200 W. Our final goal is an ultrasonic power standard of up to 500 W. The calorimetric method is an alternative ultrasonic power measurement method to the RFB method. We have adopted this method and use water as the heating material. Water has excellent features as a standard material, because the physical properties of water are well known. In the present study, we present an experimental system and the results for an ultrasonic power standard of up to 100 W. The measured ultrasonic power agreed well with the NMIJ primary standard up to 25 W.

Kikuchi, T.; Uchida, T.

2011-02-01

156

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

PubMed Central

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

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

2014-01-01

157

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

SciTech Connect

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, and 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 appropriate equation of state to represent compressibility of the liquid phase. To accomplish this satisfactorily, the proposed work includes three tasks: (1) Refinement of the characterization procedure to include distribution of sulfur, oxygen and nitrogen heteroatoms in coal liquids; (2) Measurement of high temperature (up to 400 C) and high pressure (up to 1000 psi) VLE data for binary systems of selected model compounds; and (3) Development of the thermodynamic model. The final product will include a computer program which with measurable properties of coal liquids as input, will give results for phase coexistence properties and excess enthalpies in the liquid phase. Data compilation of low pressure excess enthalpy data for binary systems of polyatomic compounds has been completed. Systems with temperature ranges and literature references are given in Table 1. Literature search is currently under way for high pressure excess enthalpy data on these systems. Current work involves completing the UNIFAC binary interaction parameter matrix, by regressing the unavailable parameters from experimental VLE and excess enthalpy data. 92 refs., 1 tab.

Kabadi, V.N.

1990-01-01

158

74 FR 7625 - Social Security Ruling, SSR 09-2p.; Title XVI: Determining Childhood Disability-Documenting a...  

Federal Register 2010, 2011, 2012, 2013

...social or emotional development...their level of academic skills and related...or a formal intelligence or language...development or academic skills and...as teacher-student ratio. This...Educational Performance. The first...development) or academic skills...

2009-02-18

159

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

160

Calorimetric Study of Yttrium and Rare-Earth Iron Garnets Between 0.4 And 4.5 Deg K.  

National Technical Information Service (NTIS)

Presented are the results of a calorimetric study on iron-garnet polycrystalline samples of Y, Eu, Tm, Sm, and Yb between 0.4 and 4.2K in zero magnetic field. Results for another sample of YIG between 0.7 and 4.2K in magnetic fields up to 13 kOe are also ...

A. J. Henderson D. G. Onn H. Meyer J. P. Remeika

1969-01-01

161

Biophysical studies on the base specificity and energetics of the DNA interaction of photoactive dye thionine: Spectroscopic and calorimetric approach  

Microsoft Academic Search

In this study absorbance, fluorescence, circular dichroic spectroscopy, viscosity, thermal melting and calorimetric techniques were employed to understand the binding of the phenothiazinium dye, thionine, with deoxyribonucleic acids of varying base composition. Strong hypochromic and bathochromic effects and quenching of fluorescence were observed that showed strong binding of thionine to the DNAs. The binding parameters evaluated from Scatchard analysis through

Puja Paul; Maidul Hossain; Ram C. Yadav; Gopinatha Suresh Kumar

2010-01-01

162

Differential scanning calorimetric (DSC) measurements on the roe of rainbow trout ( Oncorhynchus mykiss): influence of maturation and technological treatment  

Microsoft Academic Search

The roe of rainbow trout was investigated with respect to the effects of maturation and technological steps on the differential scanning calorimetric (DSC) curves of yolk proteins. The DSC curves were markedly effected during the first phase of maturation, while on the whole almost no changes were visible in the later stage. DSC curves measured on yolk proteins of rainbow

Reinhard Schubring

2004-01-01

163

Comment on 'Water bath calorimetric study of excess heat generation in resonant transfer plasmas' [J. Appl. Phys. 96, 3095 (2004)  

SciTech Connect

We show that Phillips et al. [J. Appl. Phys. 96, 3095 (2004)] have not made convincing calorimetric tests of the model of energy generation by Mills et al. [Int. J. Hydrogen Energy 25, 1171 (2000)]. In addition, we contend that the other experiments discussed by Phillips et al. are misinterpreted as providing support for the energy generation model.

Phelps, A.V. [JILA, University of Colorado, Boulder, Colorado 80309-0440 (United States)

2005-09-15

164

Idebenone loaded solid lipid nanoparticles: Calorimetric studies on surfactant and drug loading effects.  

PubMed

In this study we prepared solid lipid nanoparticles (SLN), by the phase inversion temperature (PIT) method, using cetyl palmitate as solid lipid and three different non-ionic emulsifiers of the polyoxyethylene ethers family (ceteth-20, isoceteth-20, oleth-20). These SLN were loaded with different amount of idebenone (IDE), an antioxidant drug useful in the treatment of neurodegenerative diseases and skin oxidative damages. The differential scanning calorimetry (DSC) was employed to evaluate the effects of the different emulsifiers and the different amounts of drug loaded on the thermotropic behavior of SLN and to investigate how the drug was arranged into these nanoparticles. The IDE seemed to be located into different regions of the SLN depending on its concentration and on the surfactant used. The results of this study suggest that the calorimetric studies performed on SLN could provide valuable information to optimize SLN design and drug release from these carriers. PMID:24845103

Sarpietro, Maria Grazia; Accolla, Maria Lorena; Puglisi, Giovanni; Castelli, Francesco; Montenegro, Lucia

2014-08-25

165

Biodegradable composites filled with halloysite nanonotubes: Calorimetric investigations and structural issues  

NASA Astrophysics Data System (ADS)

Halloysite nanotubes were dispersed in a commercially biodegradable blends by melt compounding. Bionanocomposites based on a film-grade commercial blend of poly(hydroxybutirate)-co-valerate PHBV and poly(butylene adipate-co-therephthalate) PBAT and containg up to 10% by weigth of tubular clays (HNTs) were prepared by using a twin-screw lab extruder and filmed by a film-blowing equipment. Film samples were subjected to thermal and structural investigations. Calorimetric analysis showed that signals shape is clearly affected by the heating and cooling rate, respectively. Structural investigations performed by X-Ray diffraction tests satisfactorily allowed to interpret thermal behavior highlighting the occurrence of different crystalline modifications, depending on the scanning thermal rate, the inclusion of filler and its chemical functionalization.

Russo, Pietro; Vetrano, Barbara; Acierno, Domenico

2012-07-01

166

Emittance characterization of thermal control paints, coatings and surfaces using a calorimetric technique  

NASA Astrophysics Data System (ADS)

Thermal control surfaces are used in every spacecraft thermal management system to dissipate heat through radiant heat transfer. This paper describes the thermal performance of several thermal control paints, coatings, and surfaces, as characterized by a calorimetric vacuum emissometer. The emissometer is designed to measure the functional emittance of a surface based on heat transfer from an underlying substrate to the surface and from the surface or near surface to a surrounding cold wall. Emittance measurements were made between 200 and 350 K. Polished aluminum, used here as a standard, was found to have a total hemispherical emittance of 0.06, as expected. A velvet black paint, also used here as a standard, was found to have an emittance of 0.94 at room temperature. Other surfaces of interest included a polyurethane-based black paint designated Z-306, a highly polished 316L stainless steel, and an atomic oxygen beam-textured carbon-carbon composite.

Jaworske, Donald A.

1994-12-01

167

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

168

Emittance characterization of thermal control paints, coatings and surfaces using a calorimetric technique  

NASA Technical Reports Server (NTRS)

Thermal control surfaces are used in every spacecraft thermal management system to dissipate heat through radiant heat transfer. This paper describes the thermal performance of several thermal control paints, coatings, and surfaces, as characterized by a calorimetric vacuum emissometer. The emissometer is designed to measure the functional emittance of a surface based on heat transfer from an underlying substrate to the surface and from the surface or near surface to a surrounding cold wall. Emittance measurements were made between 200 and 350 K. Polished aluminum, used here as a standard, was found to have a total hemispherical emittance of 0.06, as expected. A velvet black paint, also used here as a standard, was found to have an emittance of 0.94 at room temperature. Other surfaces of interest included a polyurethane-based black paint designated Z-306, a highly polished 316L stainless steel, and an atomic oxygen beam-textured carbon-carbon composite.

Jaworske, Donald A.

1994-01-01

169

Calorimetric study of phase transitions in a liquid-crystal-based microemulsion  

NASA Astrophysics Data System (ADS)

A lyotropic inverse micelle phase composed of water, thermotropic liquid-crystal octylcyanobiphenyl (8CB), and surfactant (DDAB) was studied by using high-resolution calorimetry on several mixtures with 3%, 8%, and 15% micelle concentration. Calorimetric results show strong depression of the isotropic to nematic (I-N) phase-transition temperature. Broad heat-capacity anomalies show the existence of a wide coexistence range of isotropic, nematic, and smectic-A phases, which mimics the behavior of a new nearly stable thermodynamic phase. An observation of the rather sharp almost bulklike nematic to smectic-A (N-A) transition at low-temperatures indicates that our heat capacity results are consistent with the phase separation scenario in which significant number of micelles is expelled during I-N conversion leaving almost pure nematic phase at lower temperatures. It was found that micelles get almost completely remixed on heating the mixture back to the isotropic phase.

Kutnjak, Zdravko; Cordoyiannis, George; Nounesis, George; Lebar, Andrija; Zalar, Boštjan; Žumer, Slobodan

2005-06-01

170

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

SciTech Connect

The objective of this project is to develop a thermodynamic model for phase equilibria and calorimetric properties of coal derived fluids. Through efforts of a previous project, a model for phase equilibria of coal derived liquids is already available. In this project, this model is to be extended to include calorimetric properties as well. The modification involves the use of the modified UNIFAC correlation with suitably regressed parameters, combined with an appropriate equation of state to represent compressibility of the liquid phase. To accomplish this satisfactorily, the proposed work includes three tasks: (1) Refinement of the characterization procedure to include distribution of sulfur, oxygen and nitrogen heteroatoms in coal liquids. This is to be accomplished by size exclusion chromatography of coal liquid samples, followed by elemental and FTIR analysis of separated fractions. (2) Measurement of high temperature (up to 400C) and high pressure (up to 1000 psi) VLE data for binary systems of selected model compounds. The VLE apparatus assembled as a part of the previous project will be used for this purpose, and (3) Development of the thermodynamic model. The final product will include a computer program which with measurable properties of coal liquids as input, will give results for phase coexistence properties and excess enthalpies in the liquid phase. The high temperature, high pressure VLE apparatus has been calibrated and tested. Some preliminary data are currently being measured to assure that the apparatus gives reproducible data. Once this is completed, binary VLE data on model compound systems will be measured. In this report we give a full report of the VLE apparatus. 5 figs.

Kabadi, V.N.

1991-01-01

171

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

SciTech Connect

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 appropriate equation of state to represent compressibility of the liquid phase. To accomplish this satisfactorily, the proposed work includes three tasks: (1) Refinement of the characterization procedure to include distribution of sulfur, oxygen and nitrogen heteroatoms in coal liquids; (2) Measurement of high temperature (up to 400 C) and high pressure (up to 1000 psi) VLE data for binary systems of selected model compounds; and (3) Development of the thermodynamic model. The final product will include a computer program which with measurable properties of coal liquids as input, will give results for phase coexistence properties and excess enthalpies in the liquid phase. Literature search for excess enthalpy data in binary and multi-component systems of compounds similar to the ones that constitute coal derived fluids is under way. These compounds include alkyl substituted mono and polyaromatics, hydroaromatics, pyridines, phenols, furans, thiophenes, pyrolles, carbazoles, etc. The high temperature high pressure apparatus designed and built as a part of the previous DOE project is being prepared for measurement of binary vapor-liquid equilibrium data. Two problems were encountered during the calibrations and start-up of the apparatus. The measurement of VLE data is therefore delayed. Current work involves development of the procedure for size exclusions chromatography of four coal liquid samples. 1 fig.

Kabadi, V.N.

1989-01-01

172

Reversibility and isotope effect of the calorimetric glass --> liquid transition of low-density amorphous ice.  

PubMed

We here report differential scanning calorimetry (DSC) scans recorded by repeatedly heating the H(2)O (D(2)O) low density amorph (LDA) which was made by isothermal decompression of very high-density amorphous ice (VHDA) at 140 K from 1.1 to 0.006 GPa. These DSC scans show a glass --> liquid transition endotherm with an onset temperature (T(g)) of approximately 137 (140) K at a heating rate of 30 K min(-1) accompanied by an increase in heat capacity of approximately 1.7 (1.5) J K(-1) mol(-1). We establish the reversibility of this effect by thermally cycling between its glassy state below 137 K and its highly viscous liquid state at 149 K. All calorimetric signatures, including H/D isotope effect, are highly similar to the signatures in hyperquenched glassy water (HGW). We argue that the observation of almost identical calorimetric traces for HGW and LDA implies that there is no need to reassign HGWs T(g) to higher temperatures provided that the viscous liquid state connected to both LDA and HGW behaves as an ideally "strong" liquid in the Angell classification. We furthermore show that LDA prepared by isothermal decompression of VHDA is more crystallization-resistant than LDA made from high-density amorphous ice (HDA) by isobaric warming. We suggest that the former route via VHDA removes "nanocrystalline remnants" in LDA which are still present in the latter after pressure-amorphization of hexagonal ice to HDA at 77 K. PMID:20066356

Elsaesser, Michael S; Winkel, Katrin; Mayer, Erwin; Loerting, Thomas

2010-01-21

173

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

174

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

NASA Technical Reports Server (NTRS)

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

Perez, Raul M.; Conroy, Bruce L.

1991-01-01

175

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

SciTech Connect

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

Giaddui, Tawfik; Cui Yunfeng; Galvin, James; Yu Yan; Xiao Ying [Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States)

2013-06-15

176

Precipitation of guinier- preston zones in aluminum- magnesium; a calorimetric analysis of liquid-Quenched and solid-Quenched alloys  

Microsoft Academic Search

A calorimetric analysis of precipitation in liquid-quenched (LQ; rapidly solidified) and solid-quenched (SQ; quenched after solution heat treatment) AlMg alloys was made. Nonisothermal annealing (constant heating rate) experiments (differential scanning calorimetry) were performed using specimens of various compositions (12 to 17 at. Pct Mg) aged at fixed temperatures (293 to 353 K) during variable times (up to 3 years). Constraints

M. van Rooyen; J. A. Sinte Maartensdijk; E. J. Mittemeijer

1988-01-01

177

Precipitation of guinier- preston zones in aluminum- magnesium; a calorimetric analysis of liquid-Quenched and solid-Quenched alloys  

Microsoft Academic Search

A calorimetric analysis of precipitation in liquid-quenched (LQ; rapidly solidified) and solid-quenched (SQ; quenched after\\u000a solution heat treatment) AlMg alloys was made. Nonisothermal annealing (constant heating rate) experiments (differential scanning\\u000a calorimetry) were performed using specimens of various compositions (12 to 17 at. Pct Mg) aged at fixed temperatures (293\\u000a to 353 K) during variable times (up to 3 years). Constraints

M. van Rooyen; J. A. Sinte Maartensdijk; E. J. Mittemeijer

1988-01-01

178

Differential scanning calorimetric evaluation of human meibomian gland secretions and model lipid mixtures: transition temperatures and cooperativity of melting  

PubMed Central

Meibomian gland secretions (or meibum) are produced by holocrine meibomian glands and are secreted in melted form onto the ocular surface of humans and animals to form a protective tear film lipid layer (TFLL). Its protective effect strongly depends on the composition and, hence, thermotropic behavior of meibum. The goal of our study was to quantitatively evaluate the melting characteristics of human meibum and model lipid mixtures using differential scanning microcalorimetry. Standard calorimetric parameters, e.g. changes in calorimetric enthalpy, transition temperatures T(m), cooperativity of melting etc. were assessed. We found that thermotropic behavior of meibum resembled that of relatively simple mixtures of unsaturated wax esters, but showed a lower change in calorimetric enthalpy, which can be indicative of a looser packing of lipids in meibum compared with pure standards and their simple mixtures. The cooperativity of melting of meibomian lipids was comparable to that of an equimolar mixture of four oleic-acid based wax esters. We demonstrated that the phase transitions in meibum start at about 10 to 15 °C and end at 35-36 °C, with T(m) being about 30 °C. The highly asymmetrical shape of the thermotropic peak of meibum is important for the physiology and biophysics of TFLL.

Lu, Hua; Wojtowicz, Jadwiga C.; Butovich, Igor A.

2013-01-01

179

Magnetic structure in cool stars. XVI - Emissions from the outer atmosphere of M-type dwarfs  

NASA Technical Reports Server (NTRS)

Consideration is given to emission from the outer atmospheres of M-type dwarfs in several spectral lines originating from the chromosphere, the transition-region, and the soft X-ray emission from the corona. It is shown that M-type dwarfs systematically deviate from relations between flux densities in soft X-rays and chromospheric and transition-region emission lines. The quantitative relation between the equivalent width of H-alpha and the Ca II, H, and K emission index is determined. It is suggested that the emission in the Balmer spectrum may result from back heating by coronal soft X-rays.

Rutten, R. G. M.; Zwaan, C.; Schrijver, C. J.; Duncan, D. K.; Mewe, R.

1989-01-01

180

Determination of apparent activation energy of concrete by isothermal calorimetry  

Microsoft Academic Search

In recent works at our laboratory, instrumentations have been developed to carry out calorimetric tests on concrete in isothermal conditions, which give much information. The objective of this article is, on the basis of this technique, to study the validity of the Arrhenius law and to determine the evolution of apparent activation energy of the concrete. This parameter is necessary

H. Kada-Benameur; E. Wirquin; B. Duthoit

2000-01-01

181

Thyroid hormone-induced differential synthesis of water-insoluble proteins in epidermal cell cultures from the hind limb of Rana catesbeiana tadpoles in stages XII-XV and XVI-XIX.  

PubMed

Hind limb epidermal cell cultures from stage XII-XV and XVI-XIX tadpoles of the American bullfrog Rana catesbeiana were maintained for 36 and 120 hr in medium containing either fetal calf serum or thyroid hormone (3,3',5-triiodothyronine, T3; 3 x 10(-10) mol/ml). T3 induces the precocious synthesis (within the first 36 hr) of a 59-kDa keratin associated with epidermal stratification in cultures from stages XII-XV. In epidermal cell cultures from stages XVI-XIX, T3 produces an overall pattern of water-insoluble proteins, including keratins, which is strikingly similar to temporally differentiated cultures (120 hr). A 73-kDa protein is among the water-insoluble proteins precociously synthesized by 36-hr-old cultures from stages XVI-XIX treated with T3. This protein, which is not immunoprecipitated by antibodies raised against keratins, corresponds in Mr and pI to a mammalian differentiation-specific desmosomal plaque protein. Immunoprecipitation of keratins from 120-hr-old cultures shows that many of the water-insoluble proteins synthesized are, indeed, keratins. Further, quantitation, by laser densitometry, of immunoprecipitated keratins from 120-hr cultures demonstrates that greater amounts of keratins, particularly the 65 and 59 kDa which are associated with a differentiated epidermis, are present in stages XVI-XIX. This study indicates that epidermal cell cultures from stages XVI-XIX respond more quickly to the differentiating effects of T3. PMID:1697275

Ketola-Pirie, C A; Atkinson, B G

1990-08-01

182

Representative payment under titles II, VIII and XVI of the Social Security Act. Final rule.  

PubMed

We are amending our rules governing how we investigate representative payee applicants. Under these rules, any payee who previously satisfied the payee investigation criteria, including a face-to-face interview, and currently serves as a payee generally need not appear for another face-to-face interview when subsequently applying to become a payee unless we determine within our discretion, that a new face-to-face interview is necessary. The payee applicant would still be required to satisfy the rest of the investigation process as set forth in the regulations. Reducing the number of subsequent face-to-face interviews of payee applicants will streamline our representative payee application process, allowing payee applicants to become qualified more quickly when they already serve as a payee. This rule also will expedite payment of benefits in certain representative payee situations and reduce the burden on our field office employees by eliminating the necessity of interviewing such payee applicants. PMID:19112702

2008-11-10

183

Calorimetric studies and lessons on fires and explosions of a chemical plant producing CHP and DCPO.  

PubMed

Cumene hydroperoxide (CHP) has been used in producing phenol, dicumyl peroxide (DCPO) and as an initiator for synthesizing acrylonitrile-butadiene-styrene (ABS) resin by copolymerization in Taiwan. Four incidents of fire and explosion induced by thermal runaway reactions were occurred in a same plant producing CHP, DCPO and bis-(tert-butylperoxy isopropyl) benzene peroxide (BIBP). The fourth fire and explosion occurred in the CHP reactor that resulted in a catastrophic damage in reaction region and even spread throughout storage area. Descriptions on the occurrences of these incidents were assessed by the features of processes, reaction schemes and unexpected side reactions. Calorimetric data on thermokinetics and pressure were used for explaining the practical consequences or which the worst cases encountered in this kind of plant. Acceptable risk associated with emergency relief system design is vital for a plant producing organic peroxide. These basic data for designing an inherently safer plant can be conducted from adiabatic calorimetry. An encouraging deduction has been drawn here, these incidents may be avoided by the implementation of API RP 520, API RP 521, DIERS technology, OSHA 1910.119 and AIChE's CCPS recommended PSM elements. PMID:22459975

Hsu, Jing-Ming; Su, Mao-Sheng; Huang, Chiao-Ying; Duh, Yih-Shing

2012-05-30

184

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

185

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

186

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

187

Binding of the anticancer alkaloid sanguinarine with tRNA(phe): spectroscopic and calorimetric studies.  

PubMed

The interaction of the natural plant alkaloid and anticancer agent sanguinarine with tRNA(phe) has been investigated by spectroscopic and calorimetric techniques. Sanguinarine iminium binds to tRNA(phe) cooperatively; alkanolamine does not bind but in presence of large tRNA(phe) concentration, a conversion from alkanolamine to iminium occurs resulting in concomitant binding of the latter. The binding affinity of the iminium to tRNA(phe) obtained from isothermal titration calorimetry was of the order of 10(5)?M(-1), which is close to that evaluated from spectroscopy. The binding was driven largely by negative enthalpy and a smaller but favourable positive entropy change. The binding was dependent on the [Na(+)] concentration, but had a larger non-electrostatic contribution to the Gibbs energy. A small heat capacity value and the enthalpy-entropy compensation in the energetics of the interaction characterized the binding of the iminium form to tRNA(phe). This study confirms that the tRNA(phe) binding moiety is the iminium form of sanguinarine. PMID:22702734

Hossain, Maidul; Kabir, Ayesha; Suresh Kumar, Gopinatha

2012-01-01

188

Characterization of commercial Li-ion batteries using electrochemical-calorimetric measurements  

NASA Astrophysics Data System (ADS)

Commercial Li-ion cells of Type 18650 dimensions and prismatic designs from different manufacturers have been tested to evaluate their performance and to study their thermal behavior using electrochemical-calorimetric methods. All cells tested in this work showed good performance and cyclability under normal operating conditions. The measured heat effect for the cells were exothermic during discharge and partially endothermic during charge. Cell impedance was measured for selected cells and showed some dependence on the state of charge or depth of discharge, with significant increase at the end of discharge due to concentration polarization. The entropy coefficient (d Eeq/d T) for the A&T (18650) and Panasonic (CGR 18650) cells were measured using potentiometric methods at different depths of discharge (DOD). The measured values for both cells showed some dependence on the DOD with some perturbation near 4.0 V, where the measured d Eeq/d T for Panasonic cell had an unexpected positive value. This was found to be consistent with the measured endothermic heat effect during discharge for the Panasonic cell near Eeq=4.0 V. This may be related to a phase change in the LiCoO 2 cathode material, as reported in the literature, and to structural transformation in the graphite used as anode material, in the Panasonic cell.

Al Hallaj, S.; Prakash, J.; Selman, J. R.

189

DNA energy landscapes via calorimetric detection of microstate ensembles of metastable macrostates and triplet repeat diseases  

PubMed Central

Biopolymers exhibit rough energy landscapes, thereby allowing biological processes to access a broad range of kinetic and thermodynamic states. In contrast to proteins, the energy landscapes of nucleic acids have been the subject of relatively few experimental investigations. In this study, we use calorimetric and spectroscopic observables to detect, resolve, and selectively enrich energetically discrete ensembles of microstates within metastable DNA structures. Our results are consistent with metastable, “native” DNA states being composed of an ensemble of discrete and kinetically stable microstates of differential stabilities, rather than exclusively being a single, discrete thermodynamic species. This conceptual construct is important for understanding the linkage between biopolymer conformational/configurational space and biological function, such as in protein folding, allosteric control of enzyme activity, RNA and DNA folding and function, DNA structure and biological regulation, etc. For the specific DNA sequences and structures studied here, the demonstration of discrete, kinetically stable microstates potentially has biological consequences for understanding the development and onset of DNA expansion and triplet repeat diseases.

Volker, Jens; Klump, Horst H.; Breslauer, Kenneth J.

2008-01-01

190

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

NASA Technical Reports Server (NTRS)

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

1993-01-01

191

Thermodynamic model for the analysis of calorimetric data of oligomeric proteins.  

PubMed

The thermodynamic parameters for the process of protein unfolding can be obtained through differential scanning calorimetry. However, the unfolding process may not be a two-state one. Between the native and the unfolded state, there may be association or dissociation processes or the formation of an intermediate state. As a consequence of this, the precise interpretation of the calorimetric data should be done with a specific thermodynamic model. In this work, we present two general models for the unfolding process of an oligomeric protein: N n right harpoon over left harpoon nN right harpoon over left harpoon nD (model A) and N n right harpoon over left harpoon I n right harpoon over left harpoon nD (model B). In model A, the first step represents the dissociation of the oligomer into the monomeric native species, and the second step represents the denaturation process. In model B, the first step represents the conformational change of the oligomer, and the second step represents the dissociation of this species with the concomitant unfolding process. A canonical ensemble was employed to describe these systems, by considering that the total protein concentration remains constant. In the present work, we show and analyze the behavior of these systems in different conditions and how this analysis could help with the identification of the unfolding mechanism experimentally observed. PMID:18939789

Burgos, Inés; Dassie, Sergio A; Fidelio, Gerardo D

2008-11-13

192

DNA energy landscapes via calorimetric detection of microstate ensembles of metastable macrostates and triplet repeat diseases.  

PubMed

Biopolymers exhibit rough energy landscapes, thereby allowing biological processes to access a broad range of kinetic and thermodynamic states. In contrast to proteins, the energy landscapes of nucleic acids have been the subject of relatively few experimental investigations. In this study, we use calorimetric and spectroscopic observables to detect, resolve, and selectively enrich energetically discrete ensembles of microstates within metastable DNA structures. Our results are consistent with metastable, "native" DNA states being composed of an ensemble of discrete and kinetically stable microstates of differential stabilities, rather than exclusively being a single, discrete thermodynamic species. This conceptual construct is important for understanding the linkage between biopolymer conformational/configurational space and biological function, such as in protein folding, allosteric control of enzyme activity, RNA and DNA folding and function, DNA structure and biological regulation, etc. For the specific DNA sequences and structures studied here, the demonstration of discrete, kinetically stable microstates potentially has biological consequences for understanding the development and onset of DNA expansion and triplet repeat diseases. PMID:19015511

Völker, Jens; Klump, Horst H; Breslauer, Kenneth J

2008-11-25

193

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

NASA Astrophysics Data System (ADS)

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.; Kashuri, K.; Iannacchione, G. S.; Zastavker, Y. V.

2009-04-01

194

Differential scanning calorimetric studies of nickel-titanium rotary endodontic instruments after simulated clinical use.  

PubMed

Differential scanning calorimetric (DSC) analyses have been performed between -130 degrees and 100 degrees C on single-segment specimens obtained from ProFile and Lightspeed nickel-titanium rotary endodontic instruments in the as-received condition and after one, three, and six periods of simulated clinical use in extracted teeth. The DSC analyses showed that both brands of instruments were always in the superelastic condition, although the enthalpy values for the transformation from martensitic NiTi to austenitic NiTi were much smaller for the Lightspeed instruments. Simulated clinical use had no evident effect upon this transformation for both brands, which is attributed to insufficient mechanical deformation of the instruments. There were substantial differences in the enthalpy change associated with the transformation from martensitic NiTi to austenitic NiTi for test segments from different positions along the shafts of the instruments and for as-received instruments from two different batches that were analyzed in this study and a previous study. These differences are attributed to variations in work hardening along the shaft during instrument fabrication and to processing differences during production of the two batches of each instrument brand. PMID:12470023

Brantley, W A; Svec, T A; Iijima, M; Powers, J M; Grentzer, T H

2002-11-01

195

Calorimetric evidence for two distinct molecular packing arrangements in stable glasses of indomethacin.  

PubMed

Indomethacin glasses of varying stabilities were prepared by physical vapor deposition onto substrates at 265 K. Enthalpy relaxation and the mobility onset temperature were assessed with differential scanning calorimetry (DSC). Quasi-isothermal temperature-modulated DSC was used to measure the reversing heat capacity during annealing above the glass transition temperature Tg. At deposition rates near 8 A/s, scanning DSC shows two enthalpy relaxation peaks and quasi-isothermal DSC shows a two-step change in the reversing heat capacity. We attribute these features to two distinct local packing structures in the vapor-deposited glass, and this interpretation is supported by the strong correlation between the two calorimetric signatures of the glass to liquid transformation. At lower deposition rates, a larger fraction of the sample is prepared in the more stable local packing. The transformation of the vapor-deposited glasses into the supercooled liquid above Tg is exceedingly slow, as much as 4500 times slower than the structural relaxation time of the liquid. PMID:19154147

Kearns, Kenneth L; Swallen, Stephen F; Ediger, M D; Sun, Ye; Yu, Lian

2009-02-12

196

A calorimetric study on diflunisal release from poly(lactide-co-glycolide) microspheres by monitoring the drug effect on dipalmitoylphosphatidylcholine liposomes: temperature and drug loading influence.  

PubMed

Diflunisal release from poly-Lactide-co-Glycolide (50:50, 34,000 MW) microspheres loaded with two different amounts of drug (2.5 +/- 0.5% and 10 +/- 0.5% w/w) was monitored by following the effects exerted by the drug on the thermotropic behavior of dipalmitoylphosphatidylcholine unilamellar vesicles at different temperatures. The effects of the drug released from the microspheres on the thermotropic behavior of lipid aqueous dispersion containing different molar ratios of drug was detected by differential scanning calorimetry and was compared with the effects exerted by the free Diflunisal. Diflunisal affects mainly the temperature (Tm) of the transition characteristic of phospholipid vesicles as model biomembrane, causing a shift toward lower values. This shift was modulated by the drug molar fraction with respect to the lipid concentration in the aqueous dispersion. Afterward, calorimetric measurements were performed on suspensions of blank liposomes added to weighed amounts of unloaded and differently Diflunisal-loaded microspheres as well as free powdered Diflunisal after incubation for increasing times at three different temperatures (25, 37, and 50 degrees C). The Tm shifts of the lipid bilayer, caused by the drug released from polymeric system as well as by the free drug during incubation periods, were compared with that caused by free drug increasing molar fractions dispersed directly on the membrane, employed as a calibration curve to obtain the fraction of drug released. This in vitro study suggests that the kinetic process involved in drug release is influenced by the amount of drug loaded in the microspheres as well as by the temperature acting on drug solubility and membrane disorder. This drug release model, monitored by the calorimetric technique shows that a) the poly-Lactide-co-Glycolide microspheres are a good delivery system able to sustain the drug release; b) the differential scanning calorimetry technique applied on the drug interaction with biomembranes constitutes a good tool to follow the drug release; 3) this model, representing an innovative alternative in vitro model, should be used to determine the different kinetics involved in the drug transfer from a drug delivery system to a membrane as uptake site. PMID:10895419

Castelli, F; Giunchedi, P; La Camera, O; Conte, U

2000-01-01

197

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

198

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

NASA Astrophysics Data System (ADS)

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

Hovis, G. L.

2013-12-01

199

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

USGS Publications Warehouse

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

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

1986-01-01

200

The Development of High-Resolution Calorimetric X-Ray Detectors for Compton Scattering Experiments.  

NASA Astrophysics Data System (ADS)

Compton scattering is a means of probing electron momentum distributions and can be used to evaluate calculations of electron wavefunctions in solids. The need for improved resolution in Compton experiments performed with high energy x-rays has motivated the development of a high resolution spectrometer. Calorimetric x-ray detectors, produced at Goddard Space Flight Center for x-rays around 6 KeV, have been adapted for use in Compton scattering research using synchrotron radiation near 40 KeV. Such detectors are operated below 0.1 K and work by measuring the temperature increase which results from the absorption of a single x-ray photon. Seeking to optimize detector efficiency and response at high energies, a number of materials were investigated as candidates for the overlayer which is affixed to a device in order to absorb the x-rays and transfer their energy to phonons. Mercury-telluride and superconducting foils of rhenium, tantalum, and tin were studied, each producing a detector response very different from the others and from that expected from the Debye heat capacity of the material. Experiments with creating quasiparticle recombination sites on the superconductors to assist the thermalization process produced no measurable change in detector response. Using tin absorbers, a resolution of 90 eV at 32 KeV was achieved. The apparatus was brought to a wiggler beam line at the Stanford Synchrotron Radiation Laboratory, where Compton profiles of silicon for the (100) and (111) directions were measured. The difference between directional profiles was consistent with the previously measured anisotropy, but no new insights into the electronic structure of silicon were provided, owing to the low number of total counts and to a degradation in resolution experienced during operation at the synchrotron. This experiment illustrated the feasibility of using such a system for Compton scattering research. It is expected that future improvements to the detectors and to the supporting apparatus will make higher resolution measurements possible. A better understanding of the physics of the thermalization of x-rays in superconductors is required. The dissertation discusses some simple models to explain the observed performance of the superconducting absorbers and outlines a plan for further investigation.

Stahle, Caroline Kilbourne

201

Biophysical studies on the base specificity and energetics of the DNA interaction of photoactive dye thionine: spectroscopic and calorimetric approach.  

PubMed

In this study absorbance, fluorescence, circular dichroic spectroscopy, viscosity, thermal melting and calorimetric techniques were employed to understand the binding of the phenothiazinium dye, thionine, with deoxyribonucleic acids of varying base composition. Strong hypochromic and bathochromic effects and quenching of fluorescence were observed that showed strong binding of thionine to the DNAs. The binding parameters evaluated from Scatchard analysis through McGhee-von Hippel analysis showed that the binding was non-cooperative and affinities of the order of 10(5)M(-)(1). The results of ferrocyanide fluorescence quenching studies and viscosity experiments, taken together suggested the intercalation of thionine while thermal melting, differential scanning calorimetry and circular dichroic studies provided evidence for the thermal stabilization and conformational perturbations associated with the binding. The thermodynamic parameters elucidated through sensitive isothermal titration calorimetric studies suggested that the binding was exothermic, characterized by negative enthalpy and large positive entropy changes and that the non-electrostatic contributions play a significant role for thionine association to DNA. The heat capacity changes obtained from the temperature dependence of enthalpy changes gave negative values suggesting substantial hydrophobic contribution in the DNA binding process of thionine. Further, an observation of enthalpy-entropy compensation in the DNA binding also suggested the involvement of multiplicity of non covalent interactions in the binding process. The base specificity of the complexation and energetics of the interaction of thionine to DNA are obtained for the first time from this study. PMID:20231052

Paul, Puja; Hossain, Maidul; Yadav, Ram C; Kumar, Gopinatha Suresh

2010-05-01

202

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

203

Calorimetrically measured enthalpies for the reaction of H[sub 2](D[sub 2]) (g) with Ti and Ti-Ni alloys at 323 K  

SciTech Connect

Reaction enthalpies have been measured calorimetrically at 323 K for the reaction 1/2H[sub 2] (g) + Ti ([alpha], hcp) [yields] TiH[sup 1.5] and for the partial molar solution of H[sub 2] in the [delta] phase. The magnitude of the enthalpy decreases from 68 at H/Ti = 0 to 65 kJ/mol H at H/Ti = 1.5. The enthalpy continues to slowly fall in magnitude with the increase of H content, and then, for (H/Ti) > 1.9, it falls more precipitously. [Delta]H[sub f][sup 0](TiH[sup 1.5]) = [minus]98.4 kJ and [Delta]H[sub f][sup 0](TiH[sub 2]) = [minus]130.3 kJ evaluated at 323 K. No differences in enthalpies were found between H and D. The results are discussed in terms of the existing solvus data for this system, which are important for the quantitative understanding of hydride-induced fracture. Enthalpies of reaction with H[sub 2] have been determined for several Ti-Ni alloys which lie in the (Ti([alpha]) + Ti[sub 2]Ni) two-phase field. The reaction with H[sub 2] initially occurs with the Ti phase and then with the Ti[sub 2]Ni phase. The enthalpies are similar for the Ti phase as for pure Ti, indicating that this phase is relatively pure Ti. Reaction with the Ti[sub 2]Ni phase shows a plateau region with an enthalpy of reaction with 1/2H[sub 2] of about [minus]30 kJ/mol H.

Luo, W. (Brookhaven National Lab., Upton, NY (United States)); Clewley, J.D.; Flanagan, T.B. (Univ. of Vermont, Burlington, VT (United States))

1993-10-01

204

Emission-Line Spectra of Ar IX-Ar XVI in the Soft X-Ray Region 20-50 Å  

NASA Astrophysics Data System (ADS)

As part of a larger project to complete a comprehensive catalog of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, we present observations of argon lines in the extreme-ultraviolet region. Our database includes wavelength measurements with standard errors, relative intensities, and line assignments for Ar IX-Ar XVI between 20 and 50 Å. The experimental data are complemented with a full set of calculations using the Hebrew University Lawrence Livermore Atomic Code (HULLAC). Despite differences in calculated and measured wavelengths, we find the calculated lines to be of great utility in analyzing our laboratory spectra. The calculated line intensities are generally sufficient to identify the strongest transitions in each charge state. We note, however, an underestimation by theory of the strength of the 3s-->2p lines relative to the 3d-->2p lines in Ar IX, Ar X, and Ar XI. The laboratory data are compared with Chandra observations of Procyon, resulting in the identification of an Ar IX line that was previously thought to be from S IX.

Lepson, J. K.; Beiersdorfer, P.; Behar, E.; Kahn, S. M.

2003-06-01

205

THE IRON PROJECT AND THE RMAX PROJECT: Radiative and CollisionalProcesses of Iron Ions - Fe I, Fe II, Fe XVI, Fe XVII  

NASA Astrophysics Data System (ADS)

Results from work in progress under the Iron Project and Rmax Project on electron impact excitation and radiative processes of photo-excitations, photoionization and electron-ion recombination will be reported. Whereas the Iron Project is involved in scattering and radiative atomic processes of iron and iron-peak elements, and the Rmax Project aims particularly at the X-ray spectroscopy of astrophysical objects. We will present (i) collision strengths of Fe II at low energies using an accurate wavefunction needed for spectral analysis of infrared region, (ii) oscillator strengths and radiative decay rates for allowed and forbidden transitions in Fe I and Fe II, (iii) photoionization and electron-ion recombination of ground state of Fe XVI for over a large energy/temperature range up to and including K-shell ionization and core excitations as observed in X-ray spectra, and (iv) photoionization cross sections of large number fine structure levels (n<=10 and 0 <= 10) needed for astrophysical and modeling work. Relativistic approach in the Breit-Pauli approximation is being employed to study these atomic processes.

Montenegro, Maximiliano; Nahar, Sultana; Pradhan, Anil; Sur, Chiranjib

2008-05-01

206

An assessment by calorimetric calculations of the potential thermal benefit of warming and humidification of insufflated carbon dioxide.  

PubMed

Heat transfer from a patient to warm and humidify insufflated carbon dioxide (CO2) during laparoscopic surgery may contribute to perioperative hypothermia. The magnitude of this effect was calculated using calorimetric calculations. Warming to 37°C and humidifying to 100%, each 100?L of insufflated CO2 would prevent a heat transfer of 3220 calories, which would result in a decrease of temperature by 0.06°C in a 70 kg patient after total body distribution of heat. We conclude that the thermal benefit of warming and humidifying insufflated CO2 is minor, particularly in comparison with other effective and inexpensive perioperative technologies, some of which are not always used out could easily be used. The decision to use heating and humidification of insufflated CO2 should be based on its other risks, benefits, and costs. PMID:24710263

Roth, Jonathan V; Sea, Stephanie

2014-06-01

207

SEM observations and differential scanning calorimetric studies of new and sterilized nickel-titanium rotary endodontic instruments.  

PubMed

Scanning electron microscopy (SEM) and differential scanning calorimetric (DSC) studies were utilized to investigate surface and microstructure of two brands of rotary nickel-titanium (NiTi) endodontic instruments, in the as-received condition and after subjection to 1, 6, and 11 sterilization cycles. A total of 66 ProFile (n = 33) and Flexmaster (n = 33) files were examined. SEM observations indicated the presence of surface imperfections and adherent material in all new and sterilized instruments and an increase in surface roughness of the instruments that underwent multiple sterilizations. DSC measurements showed that the specimens of both brands, in the as-received condition and after 11 sterilizations, were completely austenite in the oral environment temperature, suggesting that they are capable of superelastic behavior in appropriate clinical conditions. PMID:16793479

Alexandrou, Georgia B; Chrissafis, Konstantinos; Vasiliadis, Leonidas P; Pavlidou, Eleni; Polychroniadis, E K

2006-07-01

208

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

209

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 calorimetry…

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

2007-01-01

210

Comparison between self-field AC losses of a single-phase Bi-2223 cable measured by electric and calorimetric methods  

NASA Astrophysics Data System (ADS)

High- Tc power cables based on Bi-2223 tapes are under development worldwide. An important parameter for design and cost optimization is the AC loss expected during 50/60 Hz operation. Its measurement can be affected by several experimental problems that may alter the results. For this purpose, the 50 Hz losses of a 1.5 m long conductor, made by helically winding four layers of Bi-2223 tapes, were measured simultaneously by electrical and calorimetric methods in a wide range of currents up to 2 kA in order to investigate the reasons for possible discrepancies. The present, specifically designed, calorimetric system is not based on temperature distribution analysis but on the measurement of the gas boil-off rate of the liquid nitrogen bath.

Cereda, E.; Coletta, G.; Crotti, G.; Gherardi, L.; Ottoboni, G.; Zannella, S.

1998-12-01

211

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

212

Calorimetric measurements of the effect of nickel and stabrite coatings and resistive cores on AC loss in accelerator cables under fixed pressure  

Microsoft Academic Search

Calorimetric measurements of AC loss on long three- and four-layer stacks of Rutherford cable have been made with the applied field both normal to (face-on, FO, orientation) and parallel to the plane of the cable. Cables studied had bare-Cu, Ni-plated, and stabrite-coated strands; the latter were provided with metallic or insulating interlayers (cores) of, respectively, unalloyed Ti, stainless steel, and

M. D. Sumption; E. W. Collings; R. M. Scanlan

1997-01-01

213

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

214

Backbone nuclear relaxation characteristics and calorimetric investigation of the human Grb7-SH2/erbB2 peptide complex  

PubMed Central

Grb7 is a member of the Grb7 family of proteins, which also includes Grb10 and Grb14. All three proteins have been found to be overexpressed in certain cancers and cancer cell lines. In particular, Grb7 (along with the receptor tyrosine kinase erbB2) is overexpressed in 20%–30% of breast cancers. Grb7 binds to erbB2 and may be involved in cell signaling pathways that promote the formation of metastases and inflammatory responses. In a prior study, we reported the solution structure of the Grb7-SH2/erbB2 peptide complex. In this study, T1, T2, and steady-state NOE measurements were performed on the Grb7-SH2 domain, and the backbone relaxation behavior of the domain is discussed with respect to the potential function of an insert region present in all three members of this protein family. Isothermal titration calorimetry (ITC) studies were completed measuring the thermodynamic parameters of the binding of a 10-residue phosphorylated peptide representative of erbB2 to the SH2 domain. These measurements are compared to calorimetric studies performed on other SH2 domain/phosphorylated peptide complexes available in the literature.

Ivancic, Monika; Spuches, Anne M.; Guth, Ethan C.; Daugherty, Margaret A.; Wilcox, Dean E.; Lyons, Barbara A.

2005-01-01

215

Photophysical and calorimetric investigation on the structural reorganization of poly(A) by phenothiazinium dyes azure A and azure B.  

PubMed

Poly(A) has significant relevance to mRNA stability, protein synthesis and cancer biology. The ability of two phenothiazinium dyes azure A (AA) and azure B (AB) to bind single-stranded poly(A) was studied by spectroscopic and calorimetric techniques. Strong binding of the dyes and the higher affinity of AA over AB were ascertained from absorbance and fluorescence experiments. Significant perturbation of the circular dichroism spectrum of poly(A) in the presence of these molecules with formation of induced CD bands in the 300-700 nm region was observed. Strong emission polarization of the bound dyes and strong energy transfer from the adenine base pairs of poly(A) suggested intercalative binding to poly(A). Intercalative binding was confirmed from fluorescence quenching experiments and was predominantly entropy driven as evidenced from isothermal titration calorimetry data. The negative values of heat capacity indicated involvement of hydrophobic forces and enthalpy-entropy compensation suggested noncovalent interactions in the complexation for both the dyes. Poly(A) formed a self-assembled structure on the binding of both the dyes that was more favored under higher salt conditions. New insights in terms of spectroscopic and thermodynamic aspects into the self-structure formation of poly(A) by two new phenothiazinium dyes that may lead to structural and functional damage of mRNA are revealed from these studies. PMID:24953877

Paul, Puja; Suresh Kumar, Gopinatha

2014-07-16

216

High-resolution calorimetric study of the nematic to smectic- A transition in aligned liquid crystal-aerosil gels  

NASA Astrophysics Data System (ADS)

High-resolution ac calorimetry has been used to study the nematic to smectic- A (N-SmA) phase transition in the liquid crystal octylcyanobiphenyl (8CB) confined in aligned colloidal aerosil gels. A stable and robust nematic alignment was achieved by repeated thermal cycling of the samples in the presence of a strong uniform magnetic field. In some ways (such as transition temperature and integrated enthalpy), the dependence of the specific heat peak associated with the N-SmA transition on the aerosil density for aligned gels is consistent with that observed in unaligned (random) gel samples. However, a power-law analysis reveals that the behavior of the critical exponent ? is quite different. For random gels, ? varies gradually with aerosil density, whereas we find that ? for aligned gels shifts abruptly to an XY -like value for the lowest aerosil density studied and remains essentially constant as the sil density increases. This aerosil density independence of ? is consistent with the critical behavior of the smectic correlation lengths obtained from an x-ray scattering study of 8CB in aligned aerosil gels. The combined calorimetric and x-ray results indicate that the role of quenched randomness in aligned gels of 8CB+sils differs significantly from that in random gels.

Cruceanu, F.; Liang, D.; Leheny, R. L.; Garland, C. W.; Iannacchione, G. S.

2009-01-01

217

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

218

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

PubMed

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

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

2012-03-01

219

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

220

Dilatometric and calorimetric study of the graphitisation of high chromium cast iron  

Microsoft Academic Search

This study is devoted to the graphite formation in cast iron with high chromium content (8%) and especially to the determination of the conditions for secondary graphite formation using suitable thermal treatments. The solidification of the studied iron was examined by differential thermal analysis (DTA). The effect of high temperature treatments were examined using both differential calorimetry and dilatometry. Primary

L. Terziev; J. Lecomte-Beckers; V. Bojinov; R. Petrov; J. P. Breyer

221

Calorimetric study of ternary binder of calcium aluminate cement, Portland-limestone cement and FGD gypsum  

Microsoft Academic Search

To use flue gas desulfurization (FGD) gypsum and limestone as supplement of cement, conduction calorimetry was applied to\\u000a investigate the early hydration of ternary binder of calcium aluminate cement (CAC), Portland-limestone cement (PLC), and\\u000a FGD gypsum, supplemented with the determination of setting times and X-ray diffraction (XRD) analysis. Different exothermal\\u000a profiles were presented in two groups of pastes, in which

Wenbin Lou; Baohong Guan; Zhongbiao Wu

2010-01-01

222

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

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

223

Precipitation of guinier- preston zones in aluminum- magnesium; a calorimetric analysis of liquid-Quenched and solid-Quenched alloys  

NASA Astrophysics Data System (ADS)

A calorimetric analysis of precipitation in liquid-quenched (LQ; rapidly solidified) and solid-quenched (SQ; quenched after solution heat treatment) AlMg alloys was made. Nonisothermal annealing (constant heating rate) experiments (differential scanning calorimetry) were performed using specimens of various compositions (12 to 17 at. Pct Mg) aged at fixed temperatures (293 to 353 K) during variable times (up to 3 years). Constraints to be imposed on the heating rates to be applied were discussed. Attention was paid in particular to the formation on aging and dissolution on subsequent annealing of Guinier-Preston (GP) zones. Quantitative analysis of the heat of dissolution of GP-zones led to estimates for the GP-zone solvus and the enthalpy of formation of GP-zones. The kinetics of formation and dissolution of GP-zones can be interpreted in terms of nucleation and excess-vacancy enhanced diffusion of magnesium. Rates of formation and dissolution of GP-zones are higher for SQ-alloys than for LQ-alloys, which is caused by a higher amount of excess vacancies retained after drastic SQ as compared to LQ by melt spinning where cooling in the last part of the quench can be relatively slow. The activation energy of GP-zone dissolution is generally smaller than that of GP-zone formation, which is interpreted in terms of a precipitation model where vacancy voids/loops, formed during quenching and/or in the beginning of aging, become unstable at temperatures where the GP-zones dissolve. As compared to the precipitation of GP-zones, the precipitation of ?'/? particles showed an “opposite” kinetic behavior: it starts earlier in the LQ-alloys than in the SQ-alloys, which is ascribed to heterogeneous nucleation at structural heterogeneities (as grain boundaries) present with a higher density in the LQ-alloys.

van Rooyen, M.; Maartensdijk, J. A. Sinte; Mittemeijer, E. J.

1988-10-01

224

Calorimetric studies of melanotransferrin (p97) and its interaction with iron.  

PubMed

The mammalian molecule melanotransferrin (mTf), also called p97, is a member of the transferrin family of molecules. It exists in both secreted and glycosylphosphatidylinositol-anchored forms and is thought to play a role in angiogenesis and in transporting iron across the blood brain barrier. The binding affinity of iron to this molecule has not been formally established. Here, the binding of ferric ion (chelated with a 2-fold molar ratio of nitrilotriacetate) to mTf has been studied using isothermal titration calorimetry and differential scanning calorimetry. One iron-binding site was determined for mTf with similar binding characteristics to other transferrins. In the absence of bicarbonate, binding occurs quickly with an apparent association constant of 2.6 x 10(7) M(-1) at 25 degrees C. The presence of bicarbonate introduces kinetic effects that prevent direct determination of the apparent binding constant by isothermal titration calorimetry. Differential scanning calorimetry thermograms of mTf unfolding in the presence and absence of iron were therefore used to determine the apparent binding constant in the bicarbonate-containing system; at pH 7.5 and 25 degrees C, iron binding occurs in a 1:1 ratio with a K(app) of 4.4 x 10(17) M(-1). This affinity is intermediate between the high and low affinity lobes of transferrin and suggests that mTf is likely to play a significant role in iron transport where the high affinity lobe of transferrin is occupied or where transferrin is in proportionally low concentrations. PMID:15705575

Creagh, A Louise; Tiong, Jacqueline W C; Tian, Mei Mei; Haynes, Charles A; Jefferies, Wilfred A

2005-04-22

225

Calorimetric measurement of absolute terahertz power at the sub-microwatt level.  

PubMed

We developed a calorimeter for determining absolute terahertz (THz) power. The calorimeter is based on a DC substitution method using an isothermal temperature-control technique. A neutral-density optical filter glass was used as a volume absorber, and its THz absorption was evaluated by a time-domain spectrometer. Highly sensitive measurement of the absolute THz power was experimentally achieved in the range from the submicrowatt to microwatt level at room temperature. Power measurement of a continuous-wave THz source using a photomixer was demonstrated. This calorimeter is expected to demonstrate the traceability of THz power at a submicrowatt level. PMID:24690850

Iida, Hitoshi; Kinoshita, Moto; Amemiya, Kuniaki; Shimada, Yozo

2014-03-15

226

Conformational stability of bovine holo and apo adrenodoxin--a scanning calorimetric study.  

PubMed Central

Holo and apo adrenodoxin were studied by differential scanning calorimetry, absorption spectroscopy, limited proteolysis, and size-exclusion chromatography. To determine the conformational stability of adrenodoxin, a method was found that prevents the irreversible destruction of the iron-sulfur center. The approach makes use of a buffer solution that contains sodium sulfide and mercaptoethanol. The thermal transition of adrenodoxin takes place at Ttrs = 46-57 degrees C, depending on the Na2S concentration with a denaturation enthalpy of delta H = 300-380 kJ/mol. From delta H versus Ttrs a heat capacity change was determined as delta Cp = 7.5 +/- 1.2 kJ/mol/K. The apo protein is less stable than the holo protein as judged by the lower denaturation enthalpy (delta H = 93 +/- 14 kJ/mol at Ttrs = 37.4 +/- 3.3 degrees C) and the higher proteolytic susceptibility. The importance of the iron-sulfur cluster for the conformational stability of adrenodoxin and some conditions for refolding of the thermally denatured protein are discussed.

Burova, T. V.; Bernhardt, R.; Pfeil, W.

1995-01-01

227

Comparative calorimetric and spectroscopic studies of the effects of cholesterol and epicholesterol on the thermotropic phase behaviour of dipalmitoylphosphatidylcholine bilayer membranes.  

PubMed

We carried out comparative differential scanning calorimetric and Fourier transform infrared spectroscopic studies of the effects of cholesterol (Chol) and epicholesterol (EChol) on the thermotropic phase behaviour and organization of dipalmitoylphosphatidylcholine (DPPC) bilayers. EChol is an epimer of Chol in which the axially oriented hydroxyl group of C3 of Chol is replaced by an equatorially oriented hydroxyl group, resulting in a different orientation of the hydroxyl group relative to sterol fused ring system. Our calorimetric studies indicate that the incorporation of EChol is more effective than Chol is in reducing the enthalpy of the pretransition of DPPC. EChol is also initially more effective than Chol in reducing the enthalpies of both the sharp and broad components of the main phase transition of DPPC. However, at higher EChol concentrations (~30-50 mol%), EChol becomes less effective than Chol in reducing the enthalpy and cooperativity of the main phase transition, such that at sterol concentrations of 50 mol%, EChol does not completely abolish the cooperative hydrocarbon chain-melting phase transition of DPPC, while Chol does. However, EChol does not appear to form a calorimetrically detectable crystallite phase at higher sterol concentrations, suggesting that EChol, unlike Chol, may form dimers or lower order aggregates at higher sterol concentrations. Our spectroscopic studies demonstrate that EChol incorporation produces more ordered gel and comparably ordered liquid-crystalline bilayers compared to Chol, which are characterized by increased hydrogen bonding in the glycerol backbone region of the DPPC bilayer. These and other results indicate that monomeric EChol is less miscible in DPPC bilayers than is Chol at higher sterol concentrations, but perturbs their organization to a greater extent at lower sterol concentrations, probably due primarily to the larger effective cross-sectional area of the EChol molecule. Nevertheless, EChol does appear to produce a lamellar liquid-ordered phase in DPPC bilayers. PMID:18539134

Mannock, David A; Lee, Maria Y T; Lewis, Ruthven N A H; McElhaney, Ronald N

2008-10-01

228

Comparative Study of the Phenomena of Precipitation in Al-Zn-Mg Alloy by the Differential Scanning Calorimetric and the Dilatometry and Interpretation of Dilatometric Effects  

NASA Astrophysics Data System (ADS)

Our aim is to contribute to comprehension of the phenomena of precipitation in the Al-Zn-Mg alloys. For this, we have made a comparative study of the transformations of phases using the differential scanning calorimetric and the dilatometry. This last technique is relatively new in the case of Al-Zn-Mg alloys. It consists of two opposite effects (contraction and expansion) observed on the dilatometric curves. These effects translate two opposite metallurgical phenomena which are generally the precipitation and the dissolution.

Hadjadj, L.; Amira, R.; Bouchear, M.

2012-07-01

229

Calorimetric and transport properties of Zircalloy 2, Zircalloy 4, and Inconel 625  

NASA Astrophysics Data System (ADS)

This paper presents the measurements and the results on thermal and electrical transport properties of three nuclear reactor cladding materials: Zircalloy 2, Zircalloy 4, and Inconel 625. Study of these materials constituted a part of the IAEA coordinated research program aimed at the generation and establishment of a reliable and complete database of the thermal properties of reactor materials. Measured properties include thermal diffusivity, specific heat, and electrical resistivity. Thermal diffusivity was measured by the laser pulse technique. Specific heat and electrical resistivity were measured using a millisecond-resolution direct electrical pulse heating technique. Thermal conductivity was computed from the experimentally determined thermal difusivity and specific heat functions and the room temperature density values. Measurements were performed in the 20 to 1500°C temperature range, depending on the material and property concerned.

Magli?, K. D.; Perovi?, N. Lj.; Stanimirovi?, A. M.

1994-07-01

230

Calorimetric and transport properties of Zircalloy 2, Zircalloy 4, and Inconel 625  

SciTech Connect

This paper presents the measurements and the results on thermal and electrical transport properties of three nuclear reactor cladding materials: Zircalloy 2, Zircalloy 4, and Inconel 625. Study of these materials constituted a part of the IAEA coordinated research program aimed at the generation and establishment of a reliable and complete database of the thermal properties of reactor materials. Measured properties include thermal diffusivity, specific heat, and electrical resistivity. Thermal diffusivity was measured by the laser pulse technique. Specific heat and electrical resistivity were measured using a millisecond-resolution direct electrical pulse heating technique. Thermal conductivity was computed from the experimentally determined thermal diffusivity and specific heat functions and the room temperature density values. Measurements were performed in the 20 to 1500{degrees}C temperature range, depending on the material and property concerned.

Maglic, K.D.; Perovic, N.Lj.; Stanimirovic, A.M. [Institute of Nuclear Sciences, Belgrade (Yugoslavia)

1994-07-01

231

Differential Scanning Calorimetric (DSC) Analysis of Rotary Nickel-Titanium (NiTi) Endodontic File (RNEF)  

NASA Astrophysics Data System (ADS)

To determine the variation of A f along the axial length of rotary nickel-titanium endodontic files (RNEF). Three commercial brands of 4% taper RNEF: GTX (#20, 25 mm, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), K3 (#25, 25 mm) and TF (Twisted File #25, 27 mm) (Sybron Kerr, Orange, CA, USA) were cut into segments at 4 mm increment from the working tip. Regional specimens were measured for differential heat-flow over thermal cycling, generally with continuous heating or cooling (5 °C/min) and 5 min hold at set temperatures (start, finish temperatures): GTX: -55, 90 °C; K3: -55, 45 °C; TF: -55, 60 °C; using differential scanning calorimeter. This experiment demonstrated regional differences in A f along the axial length of GTX and K3 files. Similar variation was not obvious in the TF samples. A contributory effect of regional difference in strain-hardening due to grinding and machining during manufacturing is proposed.

Wu, Ray Chun Tung; Chung, C. Y.

2012-12-01

232

Calorimetric study of the entropy relation in the NaCl-KCl system  

PubMed Central

The heat capacity of one Na-rich and two K-rich samples of the NaCl–KCl (halite–sylvite) crystalline solution was investigated between 5 and 300 K. It deviated positively from ideal behaviour with a maximum at 40 K. The thereby produced excess entropy at 298.15 K was described by a symmetric Margules mixing model yielding WmS = 8.73 J/mol/K. Using enthalpy of mixing data from the literature and our data on the entropy, the solvus was calculated for a pressure of 105 Pa and compared with the directly determined solvus. The difference between them can be attributed to the effect of Na–K short range ordering (clustering).

Benisek, Artur; Dachs, Edgar

2013-01-01

233

Effect of Cholesterol and Ergosterol on the Compressibility and Volume Fluctuations of Phospholipid-Sterol Bilayers in the Critical Point Region: A Molecular Acoustic and Calorimetric Study  

PubMed Central

Although sterol-phospholipid interactions have been of interest for many years now, a complete thermodynamic profile of these systems is still missing. To contribute to a better understanding of the thermodynamic functions of these systems, we determined isothermal compressibility coefficient data for dipalmitoylphosphocholine (DPPC) and DPPC-containing cholesterol and ergosterol vesicles by means of molecular acoustics (ultrasound velocimetry and densimetry) and differential scanning and pressure perturbation calorimetric techniques. A particular focus was on the influence of the differential structural properties of the two sterols on the thermodynamic properties of lipid bilayers, and on the nature of the critical point region of phospholipid-sterol systems by determining thermodynamic fluctuation parameters. Contrary to significant changes in conformational and dynamical properties of the DPPC-sterol membranes, no marked differences were found in the various thermodynamic properties studied, including the adiabatic (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\beta}_{{\\mathrm{S}}}^{{\\mathrm{lipid}}}\\end{equation*}\\end{document}) and isothermal (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\beta}_{{\\mathrm{T}}}^{{\\mathrm{lipid}}}\\end{equation*}\\end{document}) compressibility, as well as the volume fluctuations. Differences in \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\beta}_{{\\mathrm{T}}}^{{\\mathrm{lipid}}}\\end{equation*}\\end{document} and \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\beta}_{{\\mathrm{S}}}^{{\\mathrm{lipid}}}\\end{equation*}\\end{document} become dramatic in the gel-fluid transition region only, due to a significant degree of slow relaxational processes in the microsecond time range in the transition region. Our data show no evidence for the existence of a typical critical point phenomenon in the concentration and temperature range where a critical point in the DPPC-sterol phase diagram is expected to appear. Hence, on a macroscopic level, it seems more appropriate to describe the sterol-phospholipid binary mixtures in the liquid-ordered/liquid-disordered coexistence region as a phase region consisting essentially of small nanodomains only. Such small-domain dimensions, with a series of particular properties such as increased line energy, spontaneous curvature, and limited lifetime, seem also to be typical of raftlike domains in cell membranes.

Krivanek, Roland; Okoro, Linus; Winter, Roland

2008-01-01

234

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

235

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

National Technical Information Service (NTIS)

The use of U/TEVA(reg sign) Spec columns as an alternative to solvent extraction for separation of uranium prior to its determination by various techniques (calorimetric, phosphorescence, and mass spectroscopy) was investigated. U/TEVA(reg sign) Spec colu...

C. J. Miller J. R. Del Mastro

1994-01-01

236

Calorimetric, optical and catalytic activity studies of europium chloride-polyvinyl alcohol composite system  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol (PVA) films doped with europium chloride (EuCl3) have been prepared by casting from their aqueous solutions. The phase transitions and thermal decomposition behavior of the prepared samples were investigated by thermal analysis and the interactions between the host PVA and Eu3+ were examined by FTIR spectroscopy. The optical absorption was recorded at room temperature in the range of 190-1000 nm. From the absorption edge studies, the values of the Urbach energy (Ee) were found to be 0.56 eV in case of the pure polymer; however, its value increased to be in the range of 1.21-1.75 eV. These energy values indicate that the model based on electronic transitions between localized states is not preferable and transitions are made between band tails. Optical parameters such as refractive index and complex dielectric constant have been determined. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model. Color properties of the prepared samples are discussed in the framework of CIE L*u*v* color space. The prepared samples have been used as catalysts in the photocatalytic degradation of p-nitrophenol (PNP) in aqueous solution under UV light irradiation using H2O2 as oxidizing agent. The catalytic activity of the Eu-polymer towards the photodegradation of PNP greatly increased after doping with Eu3+ ions. The highest catalytic activity was noticed at the optimum pH value of 5.5.

Mahmoud, Khaled H.; El-Bahy, Zeinhom M.; Hanafy, Ahmed I.

2011-09-01

237

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

SciTech Connect

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

Ktari, L. [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Abdelhedi, M. [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Laboratoire Leon Brouillon LLB, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France); Bouhlel, N. [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Dammak, M., E-mail: meddammak@yahoo.fr [Laboratoire de l'Etat Solide (LES), Faculte des Sciences de Sfax, 3000 Sfax (Tunisia); Cousson, A. [Laboratoire Leon Brouillon LLB, CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France)

2009-08-05

238

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

239

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

240

Determination of drug load in porous silicon microparticles by calorimetry  

NASA Astrophysics Data System (ADS)

Different kind of drugs can be loaded into the porous silicon microparticles for oral dosing. In cases where the drug is in its crystalline form in the pores, the amount of the loaded drug can be determined accurately using a calorimetric method, thermoporometry. Even if the drug substance is not in crystalline form a sophisticated estimation can be given. In this work ibuprofen, antipyrine, and ranitidine have been studied. Ibuprofen and antipyrine were easily detected and quantified, but ranitidine, which does not penetrate into the PSi microparticles in its crystalline form, could only be qualitatively determined. The possibility to quantify this kind of drug substance is also discussed.

Salonen, J.; Paski, J.; Vähä-Heikkilä, K.; Heikkilä, T.; Björkqvist, M.; Lehto, V.-P.

2005-06-01

241

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

242

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

NASA Astrophysics Data System (ADS)

The thermodynamic properties of three aluminous 2:1 clay minerals were acquired at 1.013 bars and at temperatures between 5 and 500 K using various calorimetric methods. Calorimetric measurements were performed on hydrated and dehydrated <2 ?m clay fractions of smectite MX-80 (Wyoming), illite IMt-2 (Silver Hill) and beidellite SBId-1 (Black Jack Mine). After purification, the mineralogical analyses gave the following structural formulae: NaKCa(SiAl)(AlMgFe0.1733+Fe0.0352+)O(OH)2,KNa(SiAl)(AlMgFe0.2923+Fe0.0842+)O(OH)2 and CaK(SiAl)(AlMgFe0.1123+)O(OH)2 for smectite MX-80, illite IMt-2 and beidellite SBId-1, respectively. Heat capacities were measured by low temperature adiabatic calorimetry and differential scanning calorimetry, from 5 to 500 K. Standard enthalpies of formation were obtained from solution-reaction calorimetry at 298.15 K. The standard Gibbs free energies of formation of the clay minerals were also calculated, together with the equilibrium constants at 25 °C, for anhydrous and hydrated minerals. A comparison between these experimental data and estimated values obtained from prediction models available in the literature, enabled the calculation method that appears to be the most relevant to be selected, at least for aluminous 2:1 clay minerals.

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

2012-07-01

243

Dynamic fuzzy c-means (dFCM) clustering and its application to calorimetric data reconstruction in high-energy physics  

NASA Astrophysics Data System (ADS)

In high-energy physics experiments, calorimetric data reconstruction requires a suitable clustering technique in order to obtain accurate information about the shower characteristics such as the position of the shower and energy deposition. Fuzzy clustering techniques have high potential in this regard, as they assign data points to more than one cluster, thereby acting as a tool to distinguish between overlapping clusters. Fuzzy c-means (FCM) is one such clustering technique that can be applied to calorimetric data reconstruction. However, it has a drawback: it cannot easily identify and distinguish clusters that are not uniformly spread. A version of the FCM algorithm called dynamic fuzzy c-means (dFCM) allows clusters to be generated and eliminated as required, with the ability to resolve non-uniformly distributed clusters. Both the FCM and dFCM algorithms have been studied and successfully applied to simulated data of a sampling tungsten-silicon calorimeter. It is seen that the FCM technique works reasonably well, and at the same time, the use of the dFCM technique improves the performance.

Sandhir, Radha Pyari; Muhuri, Sanjib; Nayak, Tapan K.

2012-07-01

244

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) [Knoxville, TN; Doktycz, Mitchel J. (Knoxville, TN) [Knoxville, TN

2000-01-01

245

Calorimetric and computational study of thiacyclohexane 1-oxide and thiacyclohexane 1,1-dioxide (thiane sulfoxide and thiane sulfone). Enthalpies of formation and the energy of the S=O bond.  

PubMed

A rotating-bomb combustion calorimeter specifically designed for the study of sulfur-containing compounds [J. Chem. Thermodyn. 1999, 31, 635] has been used for the determination of the enthalpy of formation of thiane sulfone, 4, Delta(f)H(o) m(g) = -394.8 +/- 1.5 kJ x mol(-1). This value stands in stark contrast with the enthalpy of formation reported for thiane itself, Delta(f)H(o) m(g) = -63.5 +/- 1.0 kJ x mol(-1), and gives evidence of the increased electronegativity of the sulfur atom in the sulfonyl group, which leads to significantly stronger C-SO2 bonds. Given the known enthalpy of formation of atomic oxygen in the gas phase, Delta(f)H(o) m(O,g) = +249.18 kJ x mol(-1), and the reported bond dissociation energy for the S=O bond in alkyl sulfones, BDE(S=O) = +470.0 kJ x mol(-1), it was possible to estimate the enthalpy of formation of thiane sulfoxide, 5, a hygroscopic compound not easy to use in experimental calorimetric measurements, Delta(f)H(o) m(5) = -174.0 kJ x mol(-1). The experimental enthalpy of formation of both 4 and 5 were closely reproduced by theoretical calculations at the G2(MP2)+ level, Delta(f)H(o) m(4) = -395.0 kJ x mol(-1) and Delta(f)H(o) m(5) = -178.0 kJ x mol(-1). Finally, calculated G2(MP2)+ values for the bond dissociation energy of the S=O bond in cyclic sulfoxide 5 and sulfone 4 are +363.7 and +466.2 kJ x mol(-1), respectively. PMID:12608789

Roux, María Victoria; Temprado, Manuel; Jiménez, Pilar; Dávalos, Juan Zenón; Notario, Rafael; Guzmán-Mejía, Ramón; Juaristi, Eusebio

2003-03-01

246

Calorimetric, x-ray diffraction, and spectroscopic studies of the thermotropic phase behavior and organization of tetramyristoyl cardiolipin membranes.  

PubMed

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

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

2007-05-01

247

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

PubMed Central

The thermotropic phase behavior and organization of aqueous dispersions of the quadruple-chained, anionic phospholipid tetramyristoyl diphosphatidylglycerol or tetramyristoyl cardiolipin (TMCL) was studied by differential scanning calorimetry, x-ray diffraction, 31P NMR, and Fourier-transform infrared (FTIR) spectroscopy. At physiological pH and ionic strength, our calorimetric studies indicate that fully equilibrated aqueous dispersions of TMCL exhibit two thermotropic phase transitions upon heating. The lower temperature transition is much less cooperative but of relatively high enthalpy and exhibits marked cooling hysteresis, whereas the higher temperature transition is much more cooperative and also exhibits a relatively high enthalpy but with no appreciable cooling hysteresis. Also, the properties of these two-phase transitions are sensitive to the ionic strength of the dispersing buffer. Our spectroscopic and x-ray diffraction data indicate that the lower temperature transition corresponds to a lamellar subgel (Lc?) to gel (L?) phase transition and the higher temperature endotherm to a L? to lamellar liquid-crystalline (L?) phase transition. At the Lc?/L? phase transition, there is a fivefold increase of the thickness of the interlamellar aqueous space from ?11 Å to ?50 Å, and this value decreases slightly at the L?/L? phase transition. The bilayer thickness (i.e., the mean phosphate-phosphate distance across the bilayer) increases from 42.8 Å to 43.5 Å at the Lc?/L? phase transition, consistent with the loss of the hydrocarbon chain tilt of ?12°, and decreases to 37.8 Å at the L?/L? phase transition. The calculated cross-sectional areas of the TMCL molecules are ?79 Å2 and ?83 Å2 in the Lc? and L? phases, respectively, and we estimate a value of ?100 Å2 in the L? phase. The combination of x-ray and FTIR spectroscopic data indicate that in the Lc? phase, TMCL molecules possess tilted all-trans hydrocarbon chains packed into an orthorhombic subcell in which the zig-zag planes of the chains are parallel, while in the L? phase the untilted, all-trans hydrocarbon chains possess rotational mobility and are packed into a hexagonal subcell, as are the conformationally disordered hydrocarbon chains in the L? phase. Our FTIR spectroscopic results demonstrate that the four carbonyl groups of the TMCL molecule become progressively more hydrated as one proceeds from the Lc? to the L? and then to the L? phase, while the two phosphate moieties of the polar headgroup are comparably well hydrated in all three phases. Our 31P-NMR results indicate that although the polar headgroup retains some mobility in the Lc? phase, its motion is much more restricted in the L? and especially in the L? phase than that of other phospholipids. We can explain most of our experimental results on the basis of the relatively small size of the polar headgroup of TMCL relative to other phospholipids and the covalent attachment of the two phosphate moieties to a single glycerol moiety, which results in a partially immobilized polar headgroup that is more exposed to the solvent than in other glycerophospholipids. Finally, we discuss the biological relevance of the unique properties of TMCL to the structure and function of cardiolipin-containing biological membranes.

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

2007-01-01

248

Calorimetric, FTIR and 1H NMR measurements in combination with DFT calculations for monitoring solid-state changes of dynamics of sibutramine hydrochloride.  

PubMed

Two forms of sibutramine hydrochloride, monohydrate and anhydrous, have been investigated by calorimetric methods, Fourier transform infrared (FTIR) absorption and (1) H nuclear magnetic resonance (NMR) measurements as well as by density functional theory (DFT) of vibrational frequencies and infrared intensities, calculations of steric hindrances and Monte Carlo simulations. The results of FTIR spectra combined with DFT calculations permitted identification of the bands corresponding to the dynamics and vibrations of water molecules. NMR study and Monte Carlo simulations revealed the occurrence of reorientation jumps of the methyl groups in sibutramine cation and also revealed that the reorientation of isopropyl group is possible only in sibutramine monohydrate hydrochloride. The hydration of sibutramine hydrochloride causes a change in the conformation of sibutramine cation. PMID:22826266

Pajzderska, Aleksandra; Chudoba, Dorota M; Mielcarek, Jadwiga; W?sicki, Jan

2012-10-01

249

Search for low-mass weakly interacting massive particles using voltage-assisted calorimetric ionization detection in the SuperCDMS experiment.  

PubMed

SuperCDMS is an experiment designed to directly detect weakly interacting massive particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this Letter, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage-assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for ten live days at the Soudan Underground Laboratory. A low energy threshold of 170??eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6??GeV/c2. PMID:24580434

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

2014-01-31

250

Magnetic and calorimetric investigations of inverse magnetocaloric effect in Pr0.46Sr0.54MnO3  

NASA Astrophysics Data System (ADS)

We investigated magnetic entropy change (?Sm) in the A-type antiferromagnet Pr0.46Sr0.54MnO3 by magnetic and differential scanning calorimetry (DSC) methods. The field-induced antiferromagnetic to ferromagnetic transition is first-order in nature and is accompanied by a large change in the latent heat as evidenced by the DSC data. The ?Sm shows an inverse magnetocaloric effect (?Sm=+9 J kg-1 K-1 for ?H=7 T) around the Neel temperature (TN=210+/-2 K) by magnetic measurement, which closely agrees with the calorimetric results. It is suggested that the large positive ?Sm results from a field-induced structural transition that accompanies the destruction of antiferromagnetism.

Naik, V. B.; Barik, S. K.; Mahendiran, R.; Raveau, B.

2011-03-01

251

Dielectric, Dilatometric and AC Calorimetric Studies of a New Phase Transition in (CH3NH3)NaSO4\\cdot6H2O  

NASA Astrophysics Data System (ADS)

Dielectric, dilatometric and AC calorimetric properties of (CH3NH3)NaSO4\\cdot6H2O in addition to a preliminary X-ray examination were investigated. The crystal at room temperature belongs to 6mm with the unit cell parameters: a{=}7.25 Å, c{=}12.93 Å and Z{=}2. It was found that the crystal undergoes a phase transition of the second order at -133.8°C (Tc). The dielectric constant along the a axis shows an anomalous break at Tc, while the dielectric constant along the c axis does not show a remarkable anomaly near Tc. Both the anomalous linear thermal expansion coefficient and the relative specific heat observed in the critical temperature region were discussed shortly.

Miyazaki, Akio; Sakata, Ken; Komukae, Masaru; Osaka, Toshio; Makita, Yasuharu

1989-10-01

252

Spectral-based calorimetric calibration of a 3CCD color camera for fast and accurate characterization and calibration of LCD displays  

NASA Astrophysics Data System (ADS)

LCD displays exhibit significant amount of variability in their tone-responses, color responses and backlight-modulation responses. LCD display characterization and calibration using a spectrometer or a color meter, however, leads to two basic deficiencies: (a) It can only generate calibration data based on a single spot on the display (usually at panel center); and (b) It generally takes a significant amount of time to do the required measurement. As a result, a fast and efficient system for a full LCD display characterization and calibration is required. Herein, a system based on a 3CCD calorimetrically-calibrated camera is presented which can be used for full characterization and calibration of LCD displays. The camera can provide full tri-stimulus measurements in real time. To achieve high-degree of accuracy, colorimetric calibration of camera is carried out based on spectral method.

Safaee-Rad, Reza; Aleksic, Milivoje

2011-02-01

253

Thermodynamic property determination in low gravity  

NASA Technical Reports Server (NTRS)

Techniques for determining heat capacities and other properties of molten metals were investigated and critically evaluated. Precisely determining heat capacities calorimetrically in space poses several problems. The weight of a drop calorimeter block along with the necessity of obtaining a large number of data points tend to make traditional approaches appear infeasible. However, for many substances exhibiting sufficiently high thermal conductivities and with known emissivities, it appears possible to investigate their properties by observing the rate of cooling of a levitated sphere which is initially at a uniform temperature above the melting point. A special advantage of the levitation method is that considerable supercooling is expected, making the study of the heat capacities of molten metals both above and below their melting points possible.

Margrave, J. L.

1977-01-01

254

A calorimetrically based method to convert toxic compounds into poly-3-hydroxybutyrate and to determine the efficiency and velocity of conversion.  

PubMed

A fed-batch method for converting toxic substrates into poly-3-hydroxybutyrate is presented. The method involves a series of batch-growth processes, regulated by adding small amounts of carbon substrate, during the course of which the concentration of the nitrogen source decreases and controls the distribution of the substrate-carbon assimilated. The addition of carbon substrate is controlled, and the small changes that occur in the growth pattern are interpreted using high-resolution reaction calorimetry. The method was tested with Ralstonia eutropha DSM 4058 growing on phenol, and Variovorax paradoxus DSM 4065 growing on sodium benzoate. The maximum carbon conversion efficiencies (CCEs) obtained, 23% and 27% respectively, were compared with the theoretically possible values. PMID:11330720

Maskow, T; Babel, W

2001-03-01

255

Calorimetric studies of the A1 to L10 transformation in binary FePt thin films with compositions in the range of 47.5-54.4 at. % Fe  

Microsoft Academic Search

Differential scanning calorimetry, in conjunction with x-ray and electron diffraction, is used to investigate the A1 to L10 ordering transformation in binary FePt films with compositions in the range of 47.5-54.4 at. % Fe. The kinetic ordering temperature, taken as the calorimetric peak temperature at a heating rate of 40 °C\\/min, decreases from 447 to 357 °C in this composition

K. Barmak; J. Kim; D. C. Berry; W. N. Hanani; K. Wierman; E. B. Svedberg; J. K. Howard

2005-01-01

256

Calorimetric and spectroscopic studies of the thermotropic phase behavior of lipid bilayer model membranes composed of a homologous series of linear saturated phosphatidylserines.  

PubMed Central

The thermotropic phase behavior of lipid bilayer model membranes composed of the even-numbered, N-saturated 1,2-diacyl phosphatidylserines was studied by differential scanning calorimetry and by Fourier-transform infrared and (31)P-nuclear magnetic resonance spectroscopy. At pH 7.0, 0.1 M NaCl and in the absence of divalent cations, aqueous dispersions of these lipids, which have not been incubated at low temperature, exhibit a single calorimetrically detectable phase transition that is fully reversible, highly cooperative, and relatively energetic, and the transition temperatures and enthalpies increase progressively with increases in hydrocarbon chain length. Our spectroscopic observations confirm that this thermal event is a lamellar gel (L(beta))-to-lamellar liquid crystalline (L(alpha)) phase transition. However, after low temperature incubation, the L(beta)/L(alpha) phase transition of dilauroyl phosphatidylserine is replaced by a higher temperature, more enthalpic, and less cooperative phase transition, and an additional lower temperature, less enthalpic, and less cooperative phase transition appears in the longer chain phosphatidylserines. Our spectroscopic results indicate that this change in thermotropic phase behavior when incubated at low temperatures results from the conversion of the L(beta) phase to a highly ordered lamellar crystalline (L(c)) phase. Upon heating, the L(c) phase of dilauroyl phosphatidylserine converts directly to the L(alpha) phase at a temperature slightly higher than that of its original L(beta)/L(alpha) phase transition. Calorimetrically, this process is manifested by a less cooperative but considerably more energetic, higher-temperature phase transition, which replaces the weaker L(beta)/L(alpha) phase transition alluded to above. However, with the longer chain compounds, the L(c) phase first converts to the L(beta) phase at temperatures some 10-25 degrees C below that at which the L(beta) phase converts to the L(alpha) phase. Our results also suggest that shorter chain homologues form L(c) phases that are structurally related to, but more ordered than, those formed by the longer chain homologues, but that these L(c) phases are less ordered than those formed by other phospholipids. These studies also suggest that polar/apolar interfaces of the phosphatidylserine bilayers are more hydrated than those of other glycerolipid bilayers, possibly because of interactions between the polar headgroup and carbonyl groups of the fatty acyl chains.

Lewis, R N; McElhaney, R N

2000-01-01

257

Calorimetric study of the nematic to smectic- A and smectic- A to smectic- C phase transitions in liquid-crystal-aerosil dispersions  

NASA Astrophysics Data System (ADS)

A high-resolution calorimetric study has been carried out on nanocolloidal dispersions of aerosils in the liquid crystal 4-n -pentylphenylthiol- 4'-n -octyloxybenzoate (8¯S5) as a function of aerosil concentration and temperature spanning the smectic- C to nematic phases. Over this temperature range, this liquid crystal possesses two continuous XY phase transitions: a fluctuation-dominated nematic to smectic- A transition with ???XY=-0.013 and a mean-field smectic- A to smectic- C transition. The effective critical character of the N-SmA transition remains unchanged over the entire range of the introduced quenched random disorder while the peak height and enthalpy can be well described by considering a cutoff length scale to the quasicritical fluctuations. The robust nature of the N-SmA transition in this system contrasts with cyanobiphenyl-aerosil systems and may be due to the mesogens being nonpolar and having a long nematic range. The character of the SmA-SmC transition changes gradually with increasing disorder but remains mean field like. The heat capacity maximum at the SmA-SmC transition scales as ?S-0.5 with an apparent evolution from tricritical to a simple mean-field step behavior. These results may be generally understood as a stiffening of the liquid crystal (both the nematic elasticity as well as the smectic layer compression modulus B ) with silica density.

Roshi, A.; Iannacchione, G. S.; Clegg, P. S.; Birgeneau, R. J.; Neubert, M. E.

2005-11-01

258

Crystal structure, differential scanning calorimetric, infrared spectroscopy and theoretical studies of C(NH2)2(NH)*CH2=CHCOOH noncentrosymmetric crystal.  

PubMed

The X-ray and vibrational spectroscopic analysis of a new molecular complex of guanidine and acrylic acid are reported. The crystal of C(NH(2))(2)(NH)(*)CH(2)=CHCOOH belongs to Pna2(1) space group of orthorhombic system with Z=4, a=9.9242(34) Å, b, c=8.3951(14) Å. In the crystal structure the macroscopic symmetry center is absent. The differential scanning calorimetric (DSC) experiment of powder sample indicates on continuous phase transition at 235.8K. The room temperature infrared spectrum of guanidine*acrylic acid powder sample has been measured. The spectrum is discussed on the basis of crystallographic data. The IR spectra for the powder sample were also measured at low temperatures (12-300 K). The temperature relationships of band position for obtained spectra are analyzed. Additionally, the results of theoretical calculation of vibrational spectra, equilibrium structure, HOMO, LUMO and first order hyperpolarizability are presented. PMID:23299021

Drozd, M; Dudzic, D; Pietraszko, A

2013-03-15

259

A practical method to determine the heating and cooling curves of x-ray tube assemblies  

SciTech Connect

A practical method to determine the heating and cooling curves of x-ray tube assemblies with rotating anode x-ray tube is proposed. Available procedures to obtain these curves as described in the literature are performed during operation of the equipment, and the precision of the method depends on the knowledge of the total energy applied in the system. In the present work we describe procedures which use a calorimetric system and do not require the operation of the x-ray equipment. The method was applied successfully to a x-ray tube assembly that was under test in our laboratory.

Bottaro, M.; Moralles, M.; Viana, V.; Donatiello, G. L.; Silva, E. P. [Instituto de Eletrotecnica e Energia da Universidade de Sao Paulo, Av. Prof. Luciano Gualberto, 1289, CEP 05508-010, Sao Paulo, SP (Brazil); Instituto de Pesquisas Energeticas e Nucleares, Av. Prof. Lineu Prestes, 2.242, CEP 05508-000 Sao Paulo, SP (Brazil); Instituto de Eletrotecnica e Energia da Universidade de Sao Paulo, Av. Prof. Luciano Gualberto, 1289, CEP 05508-010, Sao Paulo, SP (Brazil)

2007-10-15

260

A comparative calorimetric study of the effects of cholesterol and the plant sterols campesterol and brassicasterol on the thermotropic phase behavior of dipalmitoylphosphatidylcholine bilayer membranes.  

PubMed

We present a comparative differential scanning calorimetric study of the effects of the animal sterol cholesterol (Chol) and the plant sterols campesterol (Camp) and brassicasterol (Bras) on the thermotropic phase behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers. Camp and Bras differ from Chol in having a C24 methyl group and, additionally for Bras, a C22 trans-double bond. Camp and especially Bras decrease the temperature, cooperativity and enthalpy of the DPPC pretransition more than Chol, although these effects are attenuated at higher sterol levels. This indicates that they destabilize gel-state DPPC bilayers to a greater extent, but are less soluble, than Chol. Not surprisingly, all three sterols have similar effects on the sterol-poor sharp component of the DPPC main phase transition. However, Camp and especially Bras less effectively increase the temperature and decrease the cooperativity and enthalpy of the broad component of the main transition than Chol. This indicates that at higher sterol concentrations, Camp and Bras are less miscible and less effective than Chol at ordering the hydrocarbon chains of the sterol-enriched fluid DPPC bilayers. Overall, these alkyl side chain modifications generally reduce the ability of Chol to produce its characteristic effects on DPPC bilayer physical properties. These differences are likely due to the less extended and more bent conformations of the alkyl side chains of Camp and Bras, producing sterols with a greater effective cross-sectional area and reduced length than Chol. Hence, the structure of Chol is likely optimized for maximum solubility in, as opposed to maximum ordering of, phospholipid bilayers. PMID:24704414

Benesch, Matthew G K; McElhaney, Ronald N

2014-07-01

261

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

2010-01-01

262

Thermodynamic, structural, and dynamic properties of supercooled water confined in mesoporous MCM-41 studied with calorimetric, neutron diffraction, and neutron spin echo measurements  

NASA Astrophysics Data System (ADS)

Thermodynamic, structural, and dynamic properties of heavy water (D2O) confined in mesoporous silica glass MCM-41 C10, C12, and C14 were investigated by differential scanning calorimetry, neutron diffraction, and neutron spin echo (NSE) measurements, respectively. The DSC data showed that no crystallization of D2O confined in C10 occurs in a temperature range between 298 and 180 K, and that crystalline ice is formed at 204 and 221 K for C12 and C14, respectively. For C10, the neutron radial distribution functions of confined D2O suggested a structural change in the supercooled state between 223 and 173 K. For C10 sample, it has been found that the tetrahedral-like water structure is partially enhanced in the central part of pores at 173 K. For all the samples, the intermediate scattering functions from the NSE measurements are fitted by the Kohlrausch-Williams-Watts stretched exponential function which implies that confined supercooled D2O exhibits a wide distribution of relaxation times. For C10, C12, and C14 samples, between 298 and 240 K, the relaxation times of supercooled D2O follow remarkably well the Vogel-Fulcher-Tamman equation; for C10 sample, below 240 K, the relaxation times of nonfreezing D2O show an Arrhenius type behavior. From the present experimental results on calorimetric, structural, and dynamic properties, it has been concluded that supercooled D2O confined in MCM-41 C10 experiences a transition from high-density to low-density hydrogen-bonded structure at around 229 K.

Yoshida, Koji; Yamaguchi, Toshio; Kittaka, Shigeharu; Bellissent-Funel, Marie-Claire; Fouquet, Peter

2008-08-01

263

Thermodynamic, structural, and dynamic properties of supercooled water confined in mesoporous MCM-41 studied with calorimetric, neutron diffraction, and neutron spin echo measurements.  

PubMed

Thermodynamic, structural, and dynamic properties of heavy water (D(2)O) confined in mesoporous silica glass MCM-41 C10, C12, and C14 were investigated by differential scanning calorimetry, neutron diffraction, and neutron spin echo (NSE) measurements, respectively. The DSC data showed that no crystallization of D(2)O confined in C10 occurs in a temperature range between 298 and 180 K, and that crystalline ice is formed at 204 and 221 K for C12 and C14, respectively. For C10, the neutron radial distribution functions of confined D(2)O suggested a structural change in the supercooled state between 223 and 173 K. For C10 sample, it has been found that the tetrahedral-like water structure is partially enhanced in the central part of pores at 173 K. For all the samples, the intermediate scattering functions from the NSE measurements are fitted by the Kohlrausch-Williams-Watts stretched exponential function which implies that confined supercooled D(2)O exhibits a wide distribution of relaxation times. For C10, C12, and C14 samples, between 298 and 240 K, the relaxation times of supercooled D(2)O follow remarkably well the Vogel-Fulcher-Tamman equation; for C10 sample, below 240 K, the relaxation times of nonfreezing D(2)O show an Arrhenius type behavior. From the present experimental results on calorimetric, structural, and dynamic properties, it has been concluded that supercooled D(2)O confined in MCM-41 C10 experiences a transition from high-density to low-density hydrogen-bonded structure at around 229 K. PMID:18698916

Yoshida, Koji; Yamaguchi, Toshio; Kittaka, Shigeharu; Bellissent-Funel, Marie-Claire; Fouquet, Peter

2008-08-01

264

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

265

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

266

Effects of methoxy and formyl substituents on the energetics and reactivity of ?-naphthalenes: A calorimetric and computational study.  

PubMed

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

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

2014-07-01

267

Calorimetric study of MgSiO3 garnet and pyroxene - Heat capacities, transition enthalpies, and equilibrium phase relations in MgSiO3 at high pressures and temperatures  

Microsoft Academic Search

Enthalpy of the MgSiO3 pyroxene-tetragonal garnet transition was measured by high-temperature solution calorimetry, giving 30.80 + 3.11 kJ\\/mol at 983 K. Heat capacities of MgSiO3 pyroxene and tetragonal garnet were also measured by differential scanning calorimetry from temperatures of 150 to 700 K. Using these calorimetric data and published thermodynamic data, equilibrium phase boundaries of high-pressure transitions in MgSiO3 were

Hitoshi Yusa; Masaki Akaogi; Eiji Ito

1993-01-01

268

Spectrophotometric and Calorimetric Studies of Np(V) Complexation with Sulfate at 10-70oC  

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 Np(V)/sulfate complex and determine the equilibrium constants and enthalpy of complexation at 10-70 C. Results show that the complexation of Np(V) with sulfate is weak but slightly enhanced by the increase in temperature. The complexation is endothermic and becomes more endothermic with the increase in temperature. The enhanced complexation at elevated temperatures is due to the increasingly larger entropy of complexation that exceeds the increase in enthalpy, suggesting that the complexation of Np(V) with sulfate is entropy-driven.

Rao, Linfeng; Tian, Guoxin; Xia, Yuanxian; Friese, Judah I.

2008-06-16

269

Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei XVI: A 13 Year Study of Spectral Variability in NGC 5548  

NASA Technical Reports Server (NTRS)

We present the final installment of an intensive 13 year study of variations of the optical continuum and broad H beta emission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements and 1248 H beta measurements. The H beta variations follow the continuum variations closely, with a typical time delay of about 20 days. However, a year-by-year analysis shows that the magnitude of emission-line time delay is correlated with the mean continuum flux. We argue that the data are consistent with the simple model prediction between the size of the broad-line region and the ionizing luminosity, r is proportional to L(sup 1/2)(sub ion). Moreover, the apparently linear nature of the correlation between the H beta response time and the nonstellar optical continuum F(sub opt) arises as a consequence of the changing shape of the continuum as it varies, specifically F(sub opt) is proportional to F(sup 0.56)(sub UV).

Peterson, B. M.; Berlind, P.; Bertram, R.; Bischoff, K.; Bochkarev, N. G.; Burenkov, A. N.; Calkins, M.; Carrasco, L.; Chavushyan, V. H.

2002-01-01

270

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

271

Isothermal Calorimetric Observations of the Affect of Welding on Compatibility of Stainless Steels with High-Test Hydrogen Peroxide Propellant  

NASA Technical Reports Server (NTRS)

Compatibility is determined by the surface area, the chemical constituency and the surface finish of a material. In this investigation exposed area is obviously not a factor as the welded samples had a slightly smaller surface than the unwelded, but were more reactive. The chemical makeup of welded CRES 316L and welded CRES 304L have been observed in the literature to change from the parent material as chromium and iron are segregated in zones. In particular, the ratio of chromium to iron in CRES 316L increased from 0.260 to 0.79 in the heat affected zone (HAZ) of the weld and to 1.52 in the weld bead itself. In CRES 304L the ratio of chromium to iron increased from 0.280 to 0.44 in the HAZ and to 0.33 in the weld bead. It is possible that the increased reactivity of the welded samples and of those welded without purge gas is due to this segregation phenomenon. Likewise the reactivity increased in keeping with the greater roughness of the welded and welded without purge gas samples. Therefore enhanced roughness may also be responsible for the increased reactivity.

Gostowski, Rudy C.

2002-01-01

272

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

2011-01-01

273

Radiation-driven winds of hot luminous stars XVI. Expanding atmospheres of massive and very massive stars and the evolution of dense stellar clusters  

NASA Astrophysics Data System (ADS)

Context. Starbursts play an essential role in the evolution of galaxies. In these environments, massive stars, with their short lifetimes, are of particular importance. The stellar winds of massive stars significantly influence not only on their surroundings, but the associated mass loss also profoundly affects the evolution of the stars themselves. The evolution of the dense cores of massive starburst clusters is also affected by dynamical processes induced by N-body interactions, in addition to the evolution of each star, and the formation of very massive stars with masses up to several thousand solar masses may be decisive for the evolution of the cluster. The interpretation of the corresponding observations relies mainly on the theoretical modeling of such starbursts, which is a major challenge. Aims: The primary objective is to introduce an advanced diagnostic method of O-type stellar atmospheres with winds, including an assessment of the accuracy of the determinations of abundances, stellar and wind parameters. Moreover, observational results are interpreted in the framework of our stationary, one-dimensional theory of line driven winds. Possible effects caused by non-homogeneous time dependent structures are also discussed. Methods: We combine consistent models of expanding atmospheres with stellar evolutionary calculations of massive and very massive (up to several 1000 solar masses) single stars with regard to the evolution of dense stellar clusters. Essential in this context are accurate dynamic parameters of the winds of very massive stars. Because the atmospheric mass outflow has substantial influence on the radiation field and the atomic occupation numbers, and the radiation field and the occupation numbers in turn directly influence the radiative acceleration and thus the strength and velocity of the outflow, the determination of the hydrodynamic structures requires a highly consistent treatment of the statistical equilibrium and the hydrodynamic and radiative processes in the expanding atmospheres. Results: We present computed mass loss rates, terminal wind velocities, and spectral energy distributions of massive and very massive stars of different metallicities, calculated from atmospheric models with an improved level of consistency. These computations have important implications for (i) the primordial chemical enrichment of Population III very massive stars; (ii) the age determination of globular clusters; and (iii) the formation of intermediate mass black holes in dense stellar clusters with respect to the importance of stellar wind mass loss for the evolution of their progenitor stars. Conclusions: Stellar evolutionary calculations, using the mass loss rates of very massive stars obtained in the present paper, show that very massive stars with a low metallicity lose only a very small amount of their mass; thus it is unlikely that very massive population III stars cause a significant helium enrichment of the interstellar medium. Solar-metallicity stars have higher mass-loss rates, but these are not so high to exclude very massive stars of solar metallicity, formed by dynamical processes in dense clusters, from ending their life massive enough to form intermediate-mass black holes.

Pauldrach, A. W. A.; Vanbeveren, D.; Hoffmann, T. L.

2012-02-01

274

High-speed measurement of single-electron circuits at low temperatures with bolometric and calorimetric applications  

NASA Astrophysics Data System (ADS)

This thesis consists primarily of the description of two single-electron circuits that I fabricated and measured utilizing radio-frequency techniques. A short summary of the background material necessary for understanding this area of condensed matter experiment is included as well as a discussion of the utility of these devices as charge-sensing or energy-sensing circuit elements. In the first measurement, by configuring a radio-frequency single-electron transistor as a mixer, we demonstrate a unique implementation of this device, that achieves good charge sensitivity with large bandwidth about a tunable center frequency. In our implementation we achieve a measurement bandwidth of 16 MHz, with a tunable center frequency from 0 to 1.2 GHz, demonstrated with the transistor operating at 300 mK. Ultimately this device is limited in center frequency by the RC time of the transistor's center island, which for our device is ˜1.6 GHz, close to the measured value. The measurement bandwidth is determined by the quality factor of the readout tank circuit. In the second measurement, we detect the energy-selective diffusion of electrons through a tunnel junction to perform a new type of passive, low-power dissipation thermometry. The thermometer is based on a novel, three-junction single electron transistor, which is made with a superconducting nanoscale metal island, coupled to two tunnel junctions and a capacitive gate in the standard single-electron transistor configuration, and in addition a third tunnel junction couples the transistor island to a normal metal thin-film volume, which serves as a calorimeter. Passive diffusion of electrons from the calorimeter through the third junction changes the transistor conductance, providing a thermometric signal. This device dissipates minimal power in the calorimeter, removing a stringent limit on the minimum temperatures and energy sensitivities achievable in nanoscale calorimeters and bolometers. High speed measurements were made possible by embedding the transistor in a radiofrequency impedance-matching circuit, and heat could be applied to the calorimeter in nanosecond to millisecond pulses. Measured and simulated results are presented, and potential applications to minimal back-action calorimeters and bolometers are discussed.

Swenson, Loren

275

78 FR 72744 - Agency Information Collection Activities: Proposed Request and Comment Request  

Federal Register 2010, 2011, 2012, 2013

...disability benefits under Title II or Title XVI to determine if the individuals' disabilities...their impairments, and we consider Title XVI children eligible for payment if they have...The respondents are Title II or Title XVI disability recipients or their...

2013-12-03

276

Micro-machined calorimetric biosensors  

DOEpatents

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

Doktycz, Mitchel J. (Knoxville, TN); Britton, Jr., Charles L. (Alcoa, TN); Smith, Stephen F. (Loudon, TN); Oden, Patrick I. (Plano, TX); Bryan, William L. (Knoxville, TN); Moore, James A. (Powell, TN); Thundat, Thomas G. (Knoxville, TN); Warmack, Robert J. (Knoxville, TN)

2002-01-01

277

Forschungszentrum jülich hosts icans-xvi  

Microsoft Academic Search

Organized by Forschungszentrum Jülich, the International Collaboration on Advanced Neutron Sources (ICANS) held its 16th meeting in the “Zeughaus” (historic arsenal) in the city of Neuss from May 12-15, 2003. The organizers welcomed colleagues from the member laboratories JAERI and KEK of Japan, from the U.S. National Laboratories in Argonne, Brookhaven, Los Alamos, and Oak Ridge, as well as from

Harald Conrad

2003-01-01

278

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

SciTech Connect

The aim of this project is to elucidate the mechanisms of adsorption and surface precipitation of flooding surfactants on reservoir minerals. Effect of surfactant structure, surfactant combinations and other inorganic and polymeric species will be determined using solids of relevant mineralogy. A multi-pronged approach consisting of micro & nano spectroscopy, microcalorimetry, electrokinetics, surface tension and wettability win be used to achieve the goals. The results of this study should help in controlling surfactant loss in chemical flooding and also in developing optimum structures and conditions for efficient chemical flooding processes. Adsorption of selected individual surfactants on oxide minerals was studied. The aim was to determine the effect of structure on surfactant adsorption at the solid-liquid as well as at the liquid-air interface. Nonionic polyethoxylated alkyl phenols and anionic meta xylene sulfonates (MXS) were the surfactants studied. Electrokinetic behavior was also determined along with adsorption in order to determine the role of electrostatic forces in determining the adsorption. In addition, the effect of varying the number of ethylene oxide groups on the adsorption of polyethoxylated alkyl phenols on silica was determined since the ethoxyl groups offer unique opportunities to control adsorption as well as wettability. Effect of pH was studied both because it is a parameter with first order effect and also because pH effects can help in developing mechanisms.

Somasundaran, P.

1993-05-01

279

Complete Thermodynamic Characterization of the Multiple Protonation Equilibria of the Aminoglycoside Antibiotic Paromomycin: A Calorimetric and Natural Abundance 15N NMR Study  

Microsoft Academic Search

The binding of aminoglycoside antibiotics to a broad range of macromolecular targets is coupled to protonation of one or more of the amino groups that typify this class of drugs. Determining how and to what extent this linkage influences the energetics of the aminoglycoside-macromolecule binding reaction requires a detailed understanding of the thermodynamics associated with the protonation equilibria of the

Christopher M. Barbieri; Daniel S. Pilch

2006-01-01

280

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

PubMed Central

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

Sartor, G; Hallbrucker, A; Mayer, E

1995-01-01

281

Surfactant loss control in chemical flooding: Spectroscopic and calorimetric study of adsorption and precipitation on reservoir minerals. Quarterly technical progress report, April 1, 1993--June 30, 1993  

SciTech Connect

The aim of this contract is to elucidate the mechanisms underlying adsorption and surface precipitation of flooding surfactants on reservoir minerals. The results of this study should help in controlling surfactant loss in chemical flooding and also in developing optimum structures and conditions for efficient chemical flooding processes. Adsorption of single surfactants on silica and alumina as well as the solution behavior of surfactant mixtures was studied during this quarter. The adsorption of surfactants at the solid-liquid interface was correlated with changes in interfacial behavior such as wettability and zeta potential. Surface tension was used to study interactions between surfactant mixtures in solution. Mixed micellization of sodium dodecyl sulfate and dodecyl phenoxy polyethoxylated alcohol was found to be non-ideal. Regular solution theory adequately describes the interactions. The adsorption isotherm of a cationic surfactant, tetradecyl trimethyl ammonium chloride (TTAC), on alumina was determined at two values of pH. Changes in the settling rate of alumina suspensions after TTAC adsorption were also followed to describe the evolution of the adsorbed layer. At high surface coverage it was observed that the alumina surface became hydrophilic suggesting the formation of a TTAC bilayer at the surface. Wettability of silica after adsorption of nonyl phenyl polyethoxylated alcohols (with number of polyethylene oxide groups varying from 10-40) was measured using flotation to determine the orientation of the adsorbed layer. Effect of number of ethylene oxide groups was also determined. The amount of silica floated after the nonionic surfactant adsorption was same irrespective of the ethylene oxide chain length.

Somasundaran, P.

1993-08-31

282

Equimolar mixture of 2,2,2-trifluoroethanol and 4-chloro-1-butanol is a stronger inducer of molten globule state: isothermal titration calorimetric and spectroscopic studies.  

PubMed

A mixture of 4-chloro-1-butanol and 2,2,2-Trifluoroethanol (TFE) has been used to generate Molten globule (MG) state of structurally homologous but functionally different proteins bovine alpha-lactalbumin and hen egg-white lysozyme. The thermal denaturation was done using UV-Visible spectroscopy. From UV-Visible profile, thermal transition was not observed beyond a particular concentration. There was an indication of molten globule state in case of alpha-lactalbumin from circular dichroism experiments. By intrinsic tryptophan fluorescence, acrylamide and potassium iodide quenching, 8-anilino-naphthalene sulfonic acid (ANS) binding and energy transfer studies the presence of molten globule state was confirmed. Quantitative characterization of MG state and determining the binding thermodynamics of ANS to the MG state was done using Isothermal Titration Calorimetry (ITC). Results show that alpha-lactalbumin exists in MG state at a particular concentration but lysozyme does not show features of MG state. PMID:17786546

Thoppil, Anu A; Kishore, Nand

2007-10-01

283

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

NASA Astrophysics Data System (ADS)

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 Crystallogr., Sect. B 34 (1978) 2507]. Intramolecular hydrogen bonding (intra H-bond) interactions are dominant in both structures. The IR and Raman spectral features of the solutions and of three polycrystalline o-NA polymorphs are specific for intramolecular resonance assisted H-bonds (RAHB's). The DFT calculations facilitated the almost complete assignments of bands to normal vibrations and the analysis of the measured spectra. The manifestations of weak inter H-bonds in the ? and ? crystals and in the vibrational spectra of all polymorphs are observed as well; the strongest inter H-bonds occur in the ? polymorph. The differences in lowest electronic transition energies of three ?, ? and ? layers explain their different colours: the yellowish-green of the ? form and the orange ones of the ?- and ?- phases. The least stable ? form is probably an amorphous one with the weakest inter H-bonds. The differences in relative orientations of the -NH 2, -NO 2 groups and phenyl rings in the ?- and ?-phases indicate that the o-NA polymorphism has conformational character.

Zych, Tomasz; Misiaszek, Tomasz; Szostak, M. Magdalena

2007-11-01

284

Calorimetric study of proton tunneling in solid 5-bromo-9- hydroxyphenalenone and deuteration-induced phase transitions in its deuteroxy analog  

NASA Astrophysics Data System (ADS)

The heat capacities of 5-bromo-9-hydroxyphenalenone (BHP) and its deuteroxy derivative (BDP) were measured at temperatures between 2 and 310 K. The heat capacity of BHP is a smooth function of temperature and that of BDP has two peaks at 21.3 and 33.9 K. By analyzing the data on BHP, a tunnel splitting of (64+/-2) cm-1 associated with the quantum mechanical motion of the hydrogen atom in the intramolecular O-H-O hydrogen bond was derived along with the Debye temperature 60.8 K and two Einstein temperatures 131.4 (nondegenerate) and 210.4 K (doubly degenerate). The enthalpy change of 225 J mol-1 and entropy change of 6.8 J K-1 mol-1 were determined for the total thermal effects associated with the two phase transitions in BDP. The value of the transition entropy is consistent with the twofold disorder in the high temperature phase. The tunneling energy and transition enthalpy satisfy an inequality demanded, on the assumption that the potential energies experienced by the proton and deuteron are the same, by the occurrence in BDP and nonoccurrence in BHP of the phase transitions.

Matsuo, Takasuke; Kohno, Kenichi; Inaba, Akira; Mochida, Tomoyuki; Izuoka, Akira; Sugawara, Tadashi

1998-06-01

285

The influence of cosolvents on hydrophilic and hydrophobic interactions. Calorimetric studies of parent and alkylated cyclomaltooligosaccharides in concentrated aqueous solutions of ethanol or urea.  

PubMed

Heats of dilution in water and in aqueous 7 mol kg(-1) urea and 3 mol kg(-1) ethanol of binary solutions containing cyclomaltohexaose, cyclomaltoheptaose, cyclomaltooctaose, 2-hydroxypropyl-cyclomaltohexaose (HP?CD), 2-hydroxypropyl-cyclomaltoheptaose (HP?CD), methyl-cyclomaltohexaose (Me?CD), methyl-cyclomaltoheptaose (Me?CD) and 2-hydroxypropyl-cyclomaltooctaose (HP?CD) have been determined at 298.15K by flow microcalorimetry. The purpose of this study is to gain information about the influence of urea and ethanol, which have different effects on water structure, on hydrophilic and hydrophobic interactions. The pairwise interaction coefficients of the virial expansion of the excess enthalpies were evaluated and compared to those previously obtained for binary solutions of cyclomaltohexaose and cyclomaltoheptaose. The particular behaviour of cyclomaltooligosaccharides in water is put in evidence with respect to that shown by simple oligosaccharides. The values of the interaction coefficients greatly change in dependence of the solvent medium. They are negative in water for unsubstituted cyclomaltooligosaccharides, and positive for the alkyl-substituted ones, thus marking the major role of the hydrophobic interactions. In concentrated aqueous ethanol, coefficients are negative, while they are positive in concentrated aqueous urea. Urea solvates the hydroxyl group provoking the attenuation of hydrophilic and hydrophobic interactions. Instead, the presence of the cosolvent ethanol, which lowers the relative permittivity of the medium, enhances the strength of hydrophilic interactions. PMID:18550036

Castronuovo, Giuseppina; Niccoli, Marcella

2008-11-01

286

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

287

Physicochemical determinants in the cellular responses to nanostructured amorphous silicas.  

PubMed

Amorphous silicas, opposite to crystalline polymorphs, have been regarded so far as nonpathogenic, but few studies have addressed the toxicity of the wide array of amorphous silica forms. With the advent of nanotoxicology, there has been a rising concern about the safety of silica nanoparticles to be used in nanomedicine. Here, we report a study on the toxicity of amorphous nanostructured silicas obtained with two different preparation procedures (pyrolysis vs. precipitation), the pyrogenic in two very different particle sizes, in order to assess the role of size and origin on surface properties and on the cell damage, oxidative stress, and inflammatory response elicited in murine alveolar macrophages. A quartz dust was employed as positive control and monodispersed silica spheres as negative control. Pyrogenic silicas were remarkably more active than the precipitated one as to cytotoxicity, reactive oxygen species production, lipid peroxidation, nitric oxide synthesis, and production of tumor necrosis factor-?, when compared both per mass and per unit surface. Between the two pyrogenic silicas, the larger one was the more active. Silanols density is the major difference in surface composition among the three silicas, being much larger than the precipitated one as indicated by joint calorimetric and infrared spectroscopy analysis. We assume here that full hydroxylation of a silica surface, with consequent stable coverage by water molecules, reduces/inhibits toxic behavior. The preparation route appears thus determinant in yielding potentially toxic materials, although the smallest size does not always correspond to an increased toxicity. PMID:22491428

Gazzano, Elena; Ghiazza, Mara; Polimeni, Manuela; Bolis, Vera; Fenoglio, Ivana; Attanasio, Angelo; Mazzucco, Gianna; Fubini, Bice; Ghigo, Dario

2012-07-01

288

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

2013-11-01

289

Selectivity of Ni(II) and Zn(II) binding to Sporosarcina pasteurii UreE, a metallochaperone in the urease assembly: a calorimetric and crystallographic study.  

PubMed

Urease is a nickel-dependent enzyme that plays a critical role in the biogeochemical nitrogen cycle by catalyzing the hydrolysis of urea to ammonia and carbamate. This enzyme, initially synthesized in the apo form, needs to be activated by incorporation of two nickel ions into the active site, a process driven by the dimeric metallochaperone UreE. Previous studies reported that this protein can bind different metal ions in vitro, beside the cognate Ni(II). This study explores the metal selectivity and affinity of UreE from Sporosarcina pasteurii (Sp, formerly known as Bacillus pasteurii) for cognate [Ni(II)] and noncognate [Zn(II)] metal ions. In particular, the thermodynamic parameters of SpUreE Ni(II) and Zn(II) binding have been determined using isothermal titration calorimetry. These experiments show that two Ni(II) ions bind to the protein dimer with positive cooperativity. The high-affinity site involves the conserved solvent-exposed His(100) and the C-terminal His(145), whereas the low-affinity site comprises also the C-terminal His(147). Zn(II) binding to the protein, occurring in the same protein regions and with similar affinity as compared to Ni(II), causes metal-driven dimerization of the protein dimer. The crystal structure of the protein obtained in the presence of equimolar amounts of both metal ions indicates that the high-affinity metal binding site binds Ni(II) preferentially over Zn(II). The ability of the protein to select Ni(II) over Zn(II) was confirmed by competition experiments in solution as well as by analysis of X-ray anomalous dispersion data. Overall, the thermodynamics and structural parameters that modulate the metal ion specificity of the different binding sites on the protein surface of SpUreE have been established. PMID:24126709

Zambelli, Barbara; Banaszak, Katarzyna; Merloni, Anna; Kiliszek, Agnieszka; Rypniewski, Wojciech; Ciurli, Stefano

2013-12-01

290

Macromolecular Prodrugs. XVI. Colon-Targeted Delivery—Comparison of the Rate of Release of Naproxen from Dextran Ester Prodrugs in Homogenates of Various Segments of the Pig Gastrointestinal (GI) Tract  

Microsoft Academic Search

We have determined initial rates of naproxen formation from dextran-naproxen ester prodrugs incubated in homogenates of various segments of the pig GI tract. Drug liberation proceeded 15–17 times faster in cecum and colon homogenates than in aqueous pH 7.4 buffer or homogenates of the small intestine. The degree of conjugate substitution did not affect the liberation rates, whereas enhanced drug

Claus Larsen; Elin Harboe; Marianne Johansen; Henning Peter Olesen

1989-01-01

291

Determining Densities  

NSDL National Science Digital Library

Students 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. The second is the water displacement method, used to determine the volumes of irregularly shaped objects. After the densities are determined, students create x-y scatter graphs of mass versus volume, which reveal that objects with densities less than water (floaters) lie above the graph's diagonal (representing the density of water), and those with densities greater than water (sinkers) lie below the diagonal.

Engineering K-Phd Program

292

Determining Concentration  

NSDL National Science Digital Library

Students quantify the percent of light reflected from solutions containing varying concentrations of red dye using LEGO© MINDSTORMS© NXT bricks and light sensors. They begin by analyzing a set of standard solutions with known concentrations of food coloring, and plot data to graphically determine the relationship between percent reflected light and dye concentration. Then they identify dye concentrations for two unknown solution samples based on how much light they reflect. Students gain an understanding of light scattering applications and how to determine properties of unknown samples based on a set of standard samples.

Applying Mechatronics to Promote Science (AMPS) GK-12 Program,

293

Cycles determination  

Microsoft Academic Search

Cycle determination, i.e. research and detection of quasi monochromatic signals, is certainly not an easy task. Indeed, there are numerous mathematical, or less mathematical, methods proposed for this purpose. However, pitfalls in applications are nearly as numerous as the proposed methods. This is due to the fact that the main procedures require mathematical properties which are not fulfilled in reality

J. De Prins; C. Bovy; G. Cornélissen; R. Gillard

1972-01-01

294

Calorimetric Thermometry of Meteoritic Troilite: Early Reconnaissance  

Microsoft Academic Search

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

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

1993-01-01

295

Calorimetric Study of Thermal Denaturation of ?-Lactoglobulin  

Microsoft Academic Search

Effects of pH and milk constituents (milk ultrafiltrate and ~:-casein) on de- naturation of fl-lactoglobulin were investi- gated by a dynamic method based on dif- ferential scanning calorimetry. The appar- ent reaction order of \\/Ltactoglobulin de- naturation by the dynamic method was 2.0 over the pH range of 4.0 to 9.0, which is in fair agreement with results by other

Kwan Hwa Park; Daryl B. Lund

1984-01-01

296

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

297

Spectroscopic and calorimetric investigation of short and intermediate-range structures and energetics of amorphous SiCO, SiCN, and SiBCN polymer-derived ceramics  

NASA Astrophysics Data System (ADS)

Polymer-derived ceramics (PDCs) are a new class of amorphous ceramics in the Si-B-C-N system that are synthesized by the pyrolysis of silicon-based organic polymers. PDCs are lightweight and are resistant to creep, crystallization, and oxidation at temperatures near 1800 K making them ideal for a variety of high temperature applications. In spite of being X-ray amorphous, these materials display structural heterogeneity at the nanometer length scale. Their structure and resulting properties can be drastically altered by the utilization of preceramic polymers with differing chemistry and architectures. Fundamental understanding of the atomic structure is critical in deciphering the structure-property relationships and ultimately in controlling their properties for specific engineering applications. The short-range atomic structure has been extensively investigated using a variety of techniques, however, the structures at length scales beyond next-nearest neighbors remained highly controversial. Here we report the results of a spectroscopic and calorimetric study of short and intermediate -range structure and energetic of SiOC and SiBCN PDCs derived from a wide variety of precursors. SiOC PDCs with different carbon contents were synthesized from polysiloxane precurors and their structures were studied using high-resolution 13C and 29Si nuclear magnetic resonance (NMR) spectroscopy. The results suggest that these PDCs consists of a continuous mass fractal backbone of corner-shared SiC xO4-x tetrahedral units with "voids" occupied by sp 2-hybridized graphitic carbon. The oxygen-rich SiCxO 4-x units are located at the interior of this backbone with a mass fractal dimension of ~ 2.5, while the carbon-rich units occupy the two-dimensional interface between the backbone and the free carbon nanodomains. Such fractal topology is expected to give rise to unusual mechanical and transport properties characteristic of fractal percolation networks. For example, elastic moduli and transport properties such as electrical conductivity and viscosity may show power-law dependence on composition near and above the percolation threshold of the SiOC network or that of the free-carbon phase. Si(B)CN PDCs with different carbon contents were synthesized by pyrolysis of poly(boro)silylcarbodiimides and poly(boro)silazane precursors and their structure and energetics were studied using multi-nuclear, one- and two- dimensional NMR spectroscopy and oxide melt solution calorimetry. The structure of the polysilylcarbodiimide-derived SiCN PDCs at lower carbon content and pyrolysis temperatures (800 oC) consists of amorphous nanodomains of sp2 carbon and silicon nitride with an interfacial bonding between N, C and Si atoms that is stabilized by the presence of hydrogen. The interfacial Si-C and N-C bonds are destroyed with concomitant hydrogen loss upon increasing the pyrolysis temperature to 1100 oC. Calorimetry results demonstrate that the mixed bonding in the interfacial regions play a key role in the thermodynamic stabilization of these PDCs. The size of the carbon domains increases with increasing carbon content until a continuous amorphous carbon matrix is formed with 55-60 wt % C. The polyborosilylcarbodiimide-derived SiBCN ceramics contain carbon and silicon nitride nanodomains with the BN domains being present predominantly at the interface. In contrast, the structure of the polyborosilazane-derived ceramics consists of significant amount of mixed bonding in the nearest-neighbor coordination environments of Si and B atoms leading to the formation of SiC xN4-x tetrahedral units and BCN2 triangular units. The interfacial region between the SiCN and C nanodomains is occupied by the BCN phase. These results demonstrate that the chemistry of the polymeric precursors exerts major influence on the microstructure and bonding in their derived ceramics.

Widgeon, Scarlett J.

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, 2011 CFR

...inter-school competition. (d) Until comparable competitive opportunities are provided to all students, regardless of sex, no student shall be barred from participation in interscholastic competition in noncontact sports except on the basis of...

2011-04-01

300

Planck intermediate results. XVI. Profile likelihoods for cosmological parameters  

NASA Astrophysics Data System (ADS)

We explore the 2013 Planck likelihood function with a high-precision multi-dimensional minimizer (Minuit). This allows a refinement of the ?CDM best-fit solution with respect to previously-released results, and the construction of frequentist confidence intervals using profile likelihoods. The agreement with the cosmological results from the Bayesian framework is excellent, demonstrating the robustness of the Planck results to the statistical methodology. We investigate the inclusion of neutrino masses, where more significant differences may appear due to the non-Gaussian nature of the posterior mass distribution. By applying the Feldman-Cousins prescription, we again obtain results very similar to those of the Bayesian methodology. However, the profile-likelihood analysis of the cosmic microwave background (CMB) combination (Planck+WP+highL) reveals a minimum well within the unphysical negative-mass region. We show that inclusion of the Planck CMB-lensing information regularizes this issue, and provide a robust frequentist upper limit ? m? ? 0.26 eV (95% confidence) from the CMB+lensing+BAO data combination.

2014-06-01

301

Determination of ideal-gas enthalpies of formation for key compounds:  

SciTech Connect

The results of a study aimed at improvement of group-contribution methodology for estimation of thermodynamic properties of organic and organosilicon 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 the condensed phase, vapor-pressure measurements, and differential scanning calorimetric (d.s.c.) heat-capacity measurements. Ideal-gas enthalpies of formation of ({plus minus})-butan-2-ol, tetradecan-1-ol, hexan-1,6-diol, methacrylamide, benzoyl formic acid, naphthalene-2,6-dicarboxylic acid dimethyl ester, and tetraethylsilane are reported. A crystalline-phase enthalpy of formation at 298.15 K was determined for naphthalene-2,6-dicarboxylic acid, which decomposed at 695 K before melting. The combustion calorimetry of tetraethylsilane used the proven fluorine-additivity methodology. Critical temperature and critical density were determined for tetraethylsilane with differential scanning calorimeter and the critical pressure was derived. Group-additivity parameters useful in the application of group- contribution correlations are derived. 112 refs., 13 figs., 19 tabs.

Steele, W.V.; Chirico, R.D.; Nguyen, A.; Hossenlopp, I.A.; Smith, N.K.

1991-10-01

302

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

303

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

304

Viscous heating effects in silicate melts: an experimental determination.  

NASA Astrophysics Data System (ADS)

Viscous heating can play an important role in the transition from effusive, low-mass flow rate to explosive, high- mass flow rate eruptions. Recent results from numerical models that calculate the fluid dynamics of explosive volcanic eruptions show that the heat generated by viscous friction produces a local increase in temperature near the tube walls. Consequently a decrease in viscosity and a strong stratification in the viscosity profile (which can trigger the onset of a sustained, steady, high mass flow rate phase of an explosive eruption, as well as for the transition from effusive to explosive behaviour) is obtained. Here we present the first experimental proof of the possibility of increasing the temperature of silicate melts by 10s of K due to dissipated mechanical energy by using a newly developed high-temperature, high-load apparatus. To study the rheology of silicate melts, we performed a viscosity study on a synthetic silicate melt (viscosity standard) and a natural calc-alkaline obsidian. The samples were placed between the two pistons of the apparatus and heated up to the desired temperature above the calorimetric glass transition temperature and the temperature was determined with 3 equi-spaced thermocouples inside the samples. After allowing the system to reach thermal equilibrium (~ 8 hours) in a parallel plate type experiment, pressure was applied (up to 110 MPa) and held up to several 10s of seconds. The temperature increase due to viscous dissipation inside the sample is a function of applied force, time and composition (up to 14 K in 8 sec at 110 MPa). In the raw data (viscosity versus time, assuming no viscous heating effect) an apparent onset of Non-Newtonian flow behaviour is observed at stress and strain rates consistent to prior data from fibre-elongation studies. However if the data are corrected for the effect of temperature on viscosity, the "apparent" onset of Non-Newtonian flow behaviour is not observed. In these deformations the viscous heating effect intercedes and generates the apparent onset of strain-rate dependence .

Hess, K.; Cordonnier, B.; Lavallée, Y.; Dingwell, D.

2006-12-01

305

Genomics of sex determination.  

PubMed

Sex determination is a major switch in the evolutionary history of angiosperm, resulting 11% monoecious and dioecious species. The genomic sequences of papaya sex chromosomes unveiled the molecular basis of recombination suppression in the sex determination region, and candidate genes for sex determination. Identification and analyses of sex determination genes in cucurbits and maize demonstrated conservation of sex determination mechanism in one lineage and divergence between the two systems. Epigenetic control and hormonal influence of sex determination were elucidated in both plants and animals. Intensive investigation of potential sex determination genes in model species will improve our understanding of sex determination gene network. Such network will in turn accelerate the identification of sex determination genes in dioecious species with sex chromosomes, which are burdensome due to no recombination in sex determining regions. The sex determination genes in dioecious species are crucial for understanding the origin of dioecy and sex chromosomes, particularly in their early stage of evolution. PMID:24682067

Zhang, Jisen; Boualem, Adnane; Bendahmane, Abdelhafid; Ming, Ray

2014-04-01

306

77 FR 2478 - Fisheries of the Exclusive Economic Zone Off Alaska; Groundfish of the Gulf of Alaska; Amendment 88  

Federal Register 2010, 2011, 2012, 2013

...xvi) Which members may That is determined by the rockfish harvest the rockfish cooperative contract signed by its cooperative's CQ? members. Any violations of this contract by one cooperative member may be...

2012-01-18

307

Calorimetric and spectroscopic study of quasi-one-dimensional Haldane magnets (Y{sub 1-x}Nd{sub x}){sub 2}BaNiO{sub 5} (x = 1, 0.75, 0.50, 0.25)  

SciTech Connect

The temperature dependences of the heat capacity and optical transmission spectra of quasi-one-dimensional Haldane magnets (Y{sub 1-x}Nd{sub x}){sub 2}BaNiO{sub 5} (x = 1, 0.75, 0.50, 0.25) have been studied. All the compounds studied undergoes antiferromagnetic ordering. In the ordered state, the internal magnetic field produces splitting of the ground-state Kramers doublet of Nd{sup 3+} ion. The temperature dependences of the magnitude of splitting, as determined from spectroscopic data, were used to calculate the Schottky anomaly on the heat capacity curve. Nonequivalent centers related to neodymium ions have been found in compounds with x = 0.75, 0.50, and 0.25.

Popova, E. A., E-mail: eapopova@yahoo.co [Moscow State Institute of Electronics and Mathematics (Technical University) (Russian Federation); Vasil'ev, A. N. [Moscow State University, Department of Physics (Russian Federation); Klimin, S. A. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation); Narozhnyi, M. V.; Popova, M. N., E-mail: popova@isan.troitsk.r [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation)

2010-08-15

308

Crystal Structure Determination of New Antimitotic Agent Bis(p-fluorobenzyl)trisulfide  

PubMed Central

The purpose of this research was to investigate the physical characteristics and crystalline structure of bis(p-fluorobenzyl)trisulfide, a new anti-tumor agent. Methods used included X-ray single crystal diffraction, X-ray powder diffraction (XRPD), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetric (DSC) and thermogravimetric (TG) analyses. The findings obtained with X-ray single crystal diffraction showed that a monoclinic unit cell was a?=?12.266(1) Å, b?=?4.7757(4) Å, c?=?25.510(1) Å, ??=?104.25(1)°; cell volume?=?1,448.4(2) Å3, Z?=?4, and space group C2/c. The XRPD studies of the four crystalline samples, obtained by recrystallization from four different solvents, indicated that they had the same diffraction patterns. The diffraction pattern stimulated from the crystal structure data is in excellent agreement with the experimental results. In addition, the identical FT-IR spectra of the four crystalline samples revealed absorption bands corresponding to S–S and C–S stretching as well as the characteristic aromatic substitution. Five percent weight loss at 163.3 °C was observed when TG was used to study the decomposition process in the temperature range of 20–200 °C. DSC also allowed for the determination of onset temperatures at 60.4(1)–60.7(3) °C and peak temperatures at 62.1(3)–62.4(3) °C for the four crystalline samples studied. The results verified that the single crystal structure shared the same crystal form with the four crystalline samples investigated.

Hu, Xiurong; Gu, Jianming; Chen, Linshen; Xu, Weiming; Mo, Xiaopeng; Xu, Wanhong; Wang, Xiaobo; Xu, Xiao

2008-01-01

309

Method for determining sumoylation  

US Patent & Trademark Office Database

The present invention relates to a method for determining SUMOylation and utilizing said SUMOylation patterns for identifying specific interaction between different binding partners. In another aspect, the present invention relates to systems allowing the determination of SUMOylation and for determining specific interaction between binding partners. Furthermore, the present invention relates to vectors and proteins relating to SUMOylation.

2013-10-08

310

CALORIMETER-BASED ADJUSTMENT OF MULTIPLICITY DETERMINED 240PU EFF KNOWN-A ANALYSIS FOR THE ASSAY OF PLUTONIUM  

SciTech Connect

In nuclear material processing facilities, it is often necessary to balance the competing demands of accuracy and throughput. While passive neutron multiplicity counting is the preferred method for relatively fast assays of plutonium, the presence of low-Z impurities (fluorine, beryllium, etc.) rapidly erodes the assay precision of passive neutron counting techniques, frequently resulting in unacceptably large total measurement uncertainties. Conversely, while calorimeters are immune to these impurity effects, the long count times required for high accuracy can be a hindrance to efficiency. The higher uncertainties in passive neutron measurements of impure material are driven by the resulting large (>>2) {alpha}-values, defined as the ({alpha},n):spontaneous fission neutron emission ratio. To counter impurity impacts for high-{alpha} materials, a known-{alpha} approach may be adopted. In this method, {alpha} is determined for a single item using a combination of gamma-ray and calorimetric measurements. Because calorimetry is based on heat output, rather than a statistical distribution of emitted neutrons, an {alpha}-value determined in this way is far more accurate than one determined from passive neutron counts. This fixed {alpha} value can be used in conventional multiplicity analysis for any plutonium-bearing item having the same chemical composition and isotopic distribution as the original. With the results of single calorimeter/passive neutron/gamma-ray measurement, these subsequent items can then be assayed with high precision and accuracy in a relatively short time, despite the presence of impurities. A calorimeter-based known-{alpha} multiplicity analysis technique is especially useful when requiring rapid, high accuracy, high precision measurements of multiple plutonium bearing items having a common source. The technique has therefore found numerous applications at the Savannah River Site. In each case, a plutonium (or mixed U/Pu) bearing item is divided into multiple containers. A single item from that batch is then selected for both neutron and calorimetric measurements; all remaining items undergo a neutron measurement only. Using the technique mentioned above, the 'true' {alpha} value determined from the first (calorimeter and passive neutron measured) item is used in multiplicity analysis for all other items in the batch. The justification for using this {alpha} value in subsequent calculations is the assumption that the chemical composition and isotopic distribution of all batch items are the same, giving a constant ({alpha},n):spontaneous fission ratio. This analysis method has been successfully applied to the KIS Facility, significantly improving measurement uncertainties and reducing processing times for numerous items. Comprehensive plans were later developed to extend the use of this method to other applications, including the K-Area Shuffler and the H-Area Pu-Blending Project. While only the feasibility study for the Shuffler has been completed, implementation of the method in the H-Area Pu-Blending Project is currently in progress and has been successfully applied to multiple items. This report serves to document the details of this method in order to serve as a reference for future applications. Also contained herein are specific examples of the application of known-{alpha} multiplicity analysis.

Dubose, F.

2012-02-21

311

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

312

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

2009-01-21

313

Determinants of Education Achievement.  

ERIC Educational Resources Information Center

A model is tested of the determinants of educational attainment among peasants on Mexico's Yucatan Peninsula, involving family background, personal characteristics (including IQ), and years of schooling available. Results indicate that the model explains much of the variance in educational attainment, and that IQ is only a minor determinant. (RW)

Lave, Charles; And Others

1981-01-01

314

Determinants of Privatization Prices  

Microsoft Academic Search

Generating government revenue is a common objective in privatization. This paper asks: what determines privatization prices? Pursuing this query helps resolve the current controversies about the bearing of speed and the role for government actions prior to privatization. The data, gathered from primary sources, encompass 361 privatized Mexican companies in 49 four-digit industry codes. The determinants of auction privatization prices

Florencio Lopez-de-Silanes

1996-01-01

315

Statistical initial orbit determination  

Microsoft Academic Search

The computation of a meaningful initial orbital element set based on angles- only data is abandoned as a futile endeavor. Rather, for the ballistic missile initial orbit determination problem in particular, the concept of 'launch folders' is extended. This allows one to decouple the observational data from the initial orbit determination problem per se. The observational data is only used

Laurence G. Taff; Barry Belkin; G. A. Schweiter; K. Sommar

1991-01-01

316

Statistical initial orbit determination  

Microsoft Academic Search

For the ballistic missile initial orbit determination problem in particular, the concept of 'launch folders' is extended. This allows to decouple the observational data from the initial orbit determination problem per se. The observational data is only used to select among the possible orbital element sets in the group of folders. Monte Carlo simulations using up to 7200 orbital element

L. G. Taff; B. Belkin; G. A. Schweiter; K. Sommar

1992-01-01

317

Determiners: A Relational Perspective  

Microsoft Academic Search

In this paper we examine from a semantic point of view a class of ex- pressions variously referred to as determiners, quantifiers, or articles. Our treatment of the meaning of these expressions reflects an idea which has its origin in the work of Montague (1970), Lewis (1972), Geach (1972), and Cresswell (1973): determiners are to be interpreted as two-place relations

Frans Zwarts; Nederlands Instituut; Rijksuniversiteit Groningen

318

ATR confinement leakage determination  

SciTech Connect

The air leakage rate from the Advanced Test Reactor (ATR) confinement is an important parameter in estimating hypothesized accidental releases of radiation to the environment. The leakage rate must be determined periodically to assure that the confinement has not degraded with time and such determination is one of the technical safety requirements of ATR operation. This paper reviews the methods of confinement leakage determination and presents an analysis of leakage determination under windy conditions, which can complicate the interpretation of the determined leakage rates. The paper also presents results of analyses of building air exchange under windy conditions. High wind can enhance air exchange and this could increase the release rates of radioisotopes following an accident.

Kuan, P.; Buescher, B.J.

1998-06-01

319

Calorimetric study of Skyrmionic chiral magnet MnSi  

NASA Astrophysics Data System (ADS)

We present the analysis of specific internal energy as a function of magnetic fields in ordered, intermediate and paramagnetic phases of MnSi. Signatures of the formation of Skyrmion lattice, in conical order region, is identified by a hump-like structure in region-I. Gradual melting of blue phase, with magnetic fields, is demonstrated.

Samatham, S. Shanmukharao; Ganesan, V.

2014-04-01

320

Calorimetric measurements on as-sb-se glasses  

Microsoft Academic Search

As-Sb-Se system, with composiiionr reprermied by (As. Sb),,b,, and hs,Sb,jSe,5~ I arc reported and discussed. The values of (he %lass iraniiiion ternperiiturr (T8j, rhc crystal1ir;itmn temperatorc (T j anti ihr. peak temperature of crystallisatvm (Tp) arc found 10 be independcot or particlc me From thc heating rate dependence of 5 and Tp vducs oi the activation cnergy lor glas, transition,

Sudha MAHADEVAN; A. Giridhar; A. K. SINGH

1986-01-01

321

Thermodynamic properties for polycyclic systems by non-calorimetric methods  

SciTech Connect

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

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

1993-03-01

322

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

323

Calorimetric study of carbon partitioning from martensite into austenite steel  

NASA Astrophysics Data System (ADS)

Quenching and partitioning (Q&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&P microstructures. Two exothermic events were observed when heating a Q&P sample from room temperature to 600°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; Föjer, Cecilia; Penning, Jan; Clarke, Amy J.; Speer, John G.

2010-09-01

324

Calorimetric thermometry of meteoritic troilite: Preliminary thermometer relationships  

NASA Technical Reports Server (NTRS)

Thermodynamic properties of the alpha/beta phase transformation in terrestrial troilite (FeS), as measured by differential scanning calorimetry (DSC), vary systematically with prior thermal history of the troilite, as imposed under laboratory conditions. Both the transition temperature and enthalpy change for the alpha/beta transformation decrease with increasing maximum temperature of prior heat treatment. DSC measurements on troilite from various meteorites indicate clear differences in the alpha/beta thermodynamic properties that are consistent with differences in the natural thermal histories of the meteorites.

Allton, Judith H.; Wentworth, Susan J.; Gooding, James L.

1994-01-01

325

Differential scanning calorimetric studies of Philippines natural grade ?-carrageenan  

Microsoft Academic Search

Using differential scanning calorimetry, the gel-sol transition temperatures were compared for KCl-precipitated ?-carrageenan and Philippines natural grade (PNG) ?-carrageenan. The latter contains cellulose, which is associated with the carrageenan in seaweed. This leads to lower gel-sol transition temperatures. More heat absorption (-?Hm = 79 kJ\\/mol) is required for the formation of junction zones for the PNG ?-carrageenan than the KCl-precipitated

R. Tanaka; T. Hatakeyama; H. Hatakeyama; G. O. Phillips

1996-01-01

326

A calorimetric study of precipitation in aluminum alloy 2219  

NASA Astrophysics Data System (ADS)

Precipitate microstructures in aluminum alloy 2219 were characterized using transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The DSC signatures of individual precipitate phases were established by comparing the DSC and TEM results from samples that had been aged such that only one precipitate phase was present. These signatures were then used to analyze the commercial tempers. It was found that DSC could readily distinguish between the T3, T4, T6, T8 and O tempers but could not distinguish amongst T81, T851 and T87. Small amounts of plastic deformation between solution treatment and aging had a significant effect on the thermograms. Aging experiments at 130 and 190 °C showed that the aging sequence and DSC response of this alloy were similar to those of pure Al-Cu when the increased copper content is taken into account. Further aging experiments at temperatures between room temperature and 130 °C showed pronounced changes of the GP zone dissolution peak as a function of aging conditions. These changes were found to be related to the effect of GP zone size on the metastable phase boundary and on the GP zone dissolution kinetics.

Papazian, John M.

1981-02-01

327

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

2013-06-15

328

Calorimetric study on interaction of dioxygen with alumina supported palladium  

Microsoft Academic Search

Pd\\/Al2O3 samples of various palladium loadings were prepared with the incipient-wetness method. With an increase in the palladium loading, the average diameter (d) of palladium crystallites on these samples was estimated from chemisorption of hydrogen to vary from 10 to 80 Å. Also, the phenomena of oxidizing these dispersed palladium crystallites with dioxygen were studied by a simultaneous TG-DSC instrument.

Yung-Shen Ho; Chen-Bin Wang; Chuin-Tih Yeh

1996-01-01

329

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

330

Spacecraft Attitude Determination Methods  

NASA Technical Reports Server (NTRS)

This document is presentation in viewgraph form, which outlines the methods of determining spacecraft attitude. The presentation reviews several parameterizations relating to spacecraft attitude, such as Euler's Theorem, Rodriques parameters, and Euler-Rodriques parameters or Quaternion. Onboard attitude determination is the norm, using either single frame or filtering methods. The presentation reviews several mathematical representations of attitude. The mechanisms for determining attitude on board the Hubble Space Telescope, the Tropical Rainfall and Measuring Mission and the Solar Anomalous and Magnetospheric Particle Explorer are reviewed. Wahba's problem, Procrustes Problem, and some solutions are also summarized.

Markley, F. Landis; Bauer, Frank H. (Technical Monitor)

2000-01-01

331

Temperature determination using pyrometry  

DOEpatents

A method for determining the temperature of a surface upon which a coating is grown using optical pyrometry by correcting Kirchhoff's law for errors in the emissivity or reflectance measurements associated with the growth of the coating and subsequent changes in the surface thermal emission and heat transfer characteristics. By a calibration process that can be carried out in situ in the chamber where the coating process occurs, an error calibration parameter can be determined that allows more precise determination of the temperature of the surface using optical pyrometry systems. The calibration process needs only to be carried out when the physical characteristics of the coating chamber change.

Breiland, William G. (Albuquerque, NM); Gurary, Alexander I. (Bridgewater, NJ); Boguslavskiy, Vadim (Princeton, NJ)

2002-01-01

332

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)] [Univ. of Vermont, Burlington, VT (United States)

1996-10-01

333

GPS Based Attitude Determination.  

National Technical Information Service (NTIS)

This final technical report describes the research performed by the Colorado Center for Astrodynamics Research for the Naval Research Laboratory (NRL) on GPS Based Attitude Determination for spacecraft over the period 01 September 1993 - 31 August 1995. T...

P. Axelrad

1995-01-01

334

Glucose Determination Apparatus.  

National Technical Information Service (NTIS)

The patent describes an electrochemical apparatus especially applicable for clinical use in determining glucose concentrations in solutions. The invention monitors the reaction of glucose oxidase on a buffered solution of glucose in the presence of a quin...

D. L. Williams

1971-01-01

335

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

336

Training Requirements Determination.  

National Technical Information Service (NTIS)

This thesis describes the process that is currently utilized by the Navy in determining training requirements for initial skill (A School) and skill progression (C School) training. The thesis presents an overall view of the Department of Defense Planning...

T. W. Coward R. L. Thomas P. B. Opsal

1981-01-01

337

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

338

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

339

Determination of DTL Configurations.  

National Technical Information Service (NTIS)

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 SUPERFI...

R. A. Tennant J. D. Schneider

1985-01-01

340

Determinants of fetal growth  

Microsoft Academic Search

Fetal growth is the end product of a variety of genetic, maternal, fetal, and placental factors. Maternal size is a dominant\\u000a determinant of birth weight. Specific nutrients and their availability modify the expression of genetically determined metabolic\\u000a and transfer systems. Hormones and growth factors of maternal, fetal, and placental origin regulate nutrient transfer and\\u000a fetal organ development. Fetal development is

David A. Sacks

2004-01-01

341

Solids mass flow determination  

DOEpatents

Method and apparatus for determining the mass flow rate of solids mixed with a transport fluid to form a flowing mixture. A temperature differential is established between the solids and fluid. The temperature of the transport fluid prior to mixing, the temperature of the solids prior to mixing, and the equilibrium temperature of the mixture are monitored and correlated in a heat balance with the heat capacities of the solids and fluid to determine the solids mass flow rate.

Macko, Joseph E. (Hempfield Township, Westmoreland County, PA)

1981-01-01

342

Genetic of gonadal determination.  

PubMed

Fetal sexual differentiation results from complex subsequent intracellular signaling and hormonal events that interact together in a definite timing. This process contributes to the setting of gonad determination, internal and external genitalia resulting in a female or male phenotype. Here, we review our current knowledge of gonadal determination drawing on insights from knock-out and transgenic mouse models and analysis of patients with disorders of sex development (DSD). PMID:24793987

Morel, Yves; Roucher, Florence; Mallet, Delphine; Plotton, Ingrid

2014-05-01

343

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

344

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  

SciTech Connect

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 enthalpy of solution the enthalpy of formation of Am(OH){sub 3} has been calculated to be {minus}1371.2{plus_minus}7.9 kj{center_dot}mol{sup {minus}1}, which represents the first experimental determination of an enthalpy of formation of any actinide hydroxide. The free energy of formation and solubility product constant of Am(OH){sub 3} (K{sub sp} = 7 {times} 10{sup {minus}31}) have been calculated from our enthalpy of formation and entropy estimates and are compared with literature measurements under near-equilibrium conditions. Since many properties of the tripositive lanthanide and actinide ions (e.g., hydrolysis, complex-ion formation, and thermochemistry) change in a regular manner, these properties can be interpreted systematically in terms of ionic size. This paper compares the thermochemistry of Am(OH){sub 3} with thermochemical studies of lanthanide hydroxides. A combined structural and acid-base model is used to explain the systematic differences in enthalpies of solution between the oxides and hydroxides of the 4f{sup n} and 5f{sup n} subgroups and to predict solubility-product constants for the actinide(III) hydroxides of Pu through Cf.

Morss, L.R.; Williams, C.W.

1993-12-31

345

Ultrasonic determination of recrystallization  

NASA Technical Reports Server (NTRS)

Ultrasonic attenuation was measured for cold worked Nickel 200 samples annealed at increasing temperatures. Localized dislocation density variations, crystalline order and colume percent of recrystallized phase were determined over the anneal temperature range using transmission electron microscopy, X-ray diffraction, and metallurgy. The exponent of the frequency dependence of the attenuation was found to be a key variable relating ultrasonic attenuation to the thermal kinetics of the recrystallization process. Identification of this key variable allows for the ultrasonic determination of onset, degree, and completion of recrystallization.

Generazio, E. R.

1986-01-01

346

Sex determination in amphibians.  

PubMed

The heterogametic sex is male in all mammals, whereas it is female in almost all birds. By contrast, there are two heterogametic types (XX/XY and ZZ/ZW) for genetic sex determination in amphibians. Though the original heterogametic sex was female in amphibians, the two heterogametic types were probably interchangeable, suggesting that sex chromosomes evolved several times in this lineage. Indeed, the frog Rana rugosa has the XX/XY and ZZ/ZW sex-determining systems within a single species, depending on the local population in Japan. The XY and ZW geographic forms with differentiated sex chromosomes probably have a common origin as undifferentiated sex chromosomes resulted from the hybridization between the primary populations of West Japan and Kanto forms. It is clear that the sex chromosomes are still undergoing evolution in this species group. Regardless of the presence of a sex-determining gene in amphibians, the gonadal sex of some species can be changed by sex steroids. Namely, sex steroids can induce the sex reversal, with estrogens inducing the male-to-female sex reversal, whereas androgens have the opposite effect. In R. rugosa, gonadal activity of CYP19 (P450 aromatase) is correlated with the feminization of gonads. Of particular interest is that high levels of CYP19 expression are observed in indifferent gonads at time before sex determination. Increases in the expression of CYP19 in female gonads and CYP17 (P450 17alpha-hydroxylase/C17-20 lyase) in male gonads suggest that the former plays an important role in phenotypic female determination, whereas the latter is needed for male determination. Thus, steroids could be the key factor for sex determination in R. rugosa. In addition to the role of sex steroids in gonadal sex determination in this species, Foxl2 and Sox3 are capable of promoting CYP19 expression. Since both the genes are autosomal, another factor up-regulating CYP19 expression must be recruited. The factor, which may be located on the X or W chromosome, intervenes directly or indirectly, in the transcriptional regulation of the CYP19 gene for feminization in amphibians. A factor up-regulating CYP17 expression remains to be identified. PMID:18996493

Nakamura, Masahisa

2009-05-01

347

Determining TOC in Waters  

ERIC Educational Resources Information Center

The instrumental method for detecting total organic carbon (TOC) in water samples is detailed. The method's limitations are discussed and certain precautions that must be taken are emphasized. The subject of TOC versus COD and BOD is investigated and TOC is determined to be a valid indication of biological demand. (BT)

Kehoe, Thomas J.

1977-01-01

348

Determinants of project success  

NASA Technical Reports Server (NTRS)

The interactions of numerous project characteristics, with particular reference to project performance, were studied. Determinants of success are identified along with the accompanying implications for client organization, parent organization, project organization, and future research. Variables are selected which are found to have the greatest impact on project outcome, and the methodology and analytic techniques to be employed in identification of those variables are discussed.

Murphy, D. C.; Baker, B. N.; Fisher, D.

1974-01-01

349

[Noninvasive cardiac output determinations].  

PubMed

The thermodilution determination of cardiac output (CO) by pulmonary arterial catheterization is considered to be the gold standard. However, a diversity of complications associated with the insertion and use of a catheter has made for the design of CO-measuring devices in a mini- or noninvasive mode. This prospective controlled study has been conducted to compare various CO determination techniques by the shape of the arterial curve (ART), as shown by the use of a transesophageal Doppler ultrasonic sensor (TEDUS) determining the blood flow velocity in the descending thoracic aorta by the Fick's backward equation with partial CO2 recirculation, by measuring thoracic bioimpedance (Tbio) by bolus thermodilution as the reference method (CO BT). In all the study examined, the mean CO values are lower than those in the reference method. In addition, there was a wide scatter of the CO values calculated by alternative methods. The mean difference and its standard deviation are 1.27 +/- 2.26 (ART); 0.87 +/- 1.57 (TEDUS); 1.01 +/- 1.46 (Fick); and 1.46 +/- 1.70 (Tbio). The errors of the methods, as compared to CO BT have the following values: APT, 27% (24-31% conference interval (CI)); TEDUS, 19% (17-21% CI); Fick, 20% (19-22%); Tbio, 25% (22-27%). By taking into account the findings, it should be stated that there is not any accurate mini- or noninvasive CO determination method that could completely substitute for the classical thermodilution technique. PMID:18051495

Subbotin, V V; Sitnikov, A V; Il'in, S A; Ovezov, A M; Chernogaeva, N V

2007-01-01

350

Sex determination in amphibians  

Microsoft Academic Search

The heterogametic sex is male in all mammals, whereas it is female in almost all birds. By contrast, there are two heterogametic types (XX\\/XY and ZZ\\/ZW) for genetic sex determination in amphibians. Though the original heterogametic sex was female in amphibians, the two heterogametic types were probably interchangeable, suggesting that sex chromosomes evolved several times in this lineage. Indeed, the

Masahisa Nakamura

2009-01-01

351

METHOD OF WEIGHT DETERMINATION  

Microsoft Academic Search

An accurate method for measuring the weight of large masses of material ; such as oil, molten metals, rubber, water, and other liquids during processing is ; patented. A short-lived radioisotope is added to the material, whose weight is ; to be determined, and uniformly dispersed in the material. A sample is taken ; from the material and weighed, and

1963-01-01

352

Satellite orbit determination  

Microsoft Academic Search

Statistical methods for determining satellite trajectories after being put into orbit, after changes in the trajectory and at regular intervals during orbital lifetime are outlined. The least squares method, a differential Gauss-Newton correction algorithm, and interpretation of the results are introduced.

P. Legendre

1984-01-01

353

Determinants of superstition  

Microsoft Academic Search

Although superstition is a common phenomenon in our modern society, only a few studies have explored empirically on what it depends. This paper investigates the factors which determine superstition, reporting some preliminary empirical results. The findings indicate that socio-demographic and socio-economic conditions matter. There seems to be a certain concurrence between churches and superstitious beliefs, the correlation between superstition and

Benno Torgler

2007-01-01

354

What Determines Firm Size?  

Microsoft Academic Search

Motivated by theories of the firm, which we classify as technological' or organizational,' we analyze the determinants of firm size across industries and across countries in a sample of 15 European countries. We find that, on average, firms facing larger markets are larger. At the industry level, we find firms in the utility sector are large, perhaps because they enjoy

Krishna B. Kumar; Raghuram G. Rajan; Luigi Zingales

1999-01-01

355

Determining the Hubble Constant  

NSDL National Science Digital Library

Students will graph distance/velocity data of real galaxies to arrive at their own value of the Hubble constant (H). Once they have calculated their own value of H, they will use it to determine distances to real galaxies with known recessional velocities.

Copeland, Cush

2012-07-11

356

Ultrasonic Determination Of Recrystallization  

NASA Technical Reports Server (NTRS)

State of recrystallization identified. Measurement of ultrasonic attenuation shows promise as means of detecting recrystallization in metal. Technique applicable to real-time acoustic monitoring of thermomechanical treatments. Starting with work-hardened material, one ultrasonically determines effect of annealing, using correlation between ultrasonic attenuation and temperature.

Generazio, Edward R.

1988-01-01

357

Gender determination in populus  

SciTech Connect

Gender, the expression of maleness or femaleness, in dioecious plants has been associated with changes in morphology, physiology, ecological position, and commercial importance of several species, including members of the Salicaceae family. Various mechanisms have been proposed to explain the expression of gender in Salicaceae, including sex chromosomes, simple Mendelian genes, quantitative genes, environment, and genotype-by-environment interactions. Published reports would favor a genetic basis for gender. The objective of this study was to identify molecular markers associated with gender in a segregating family of hybrid poplars. Bulked segregant analysis and chi-squared analysis were used to test for the occurrence of sex chromosomes, individual loci, and chromosome ratios (i.e., ploidy levels) as the mechanisms for gender determination. Examination of 2488 PCR based RAPD markers from 1219 primers revealed nine polymorphic bands between male and female bulked samples. However, linkage analysis indicated that none of these markers were significantly associated with gender. Chisquared results for difference in male-to-female ratios between diploid and triploid genotypes also revealed no significant differences. These findings suggest gender is not controlled via sex chromosomes, simple Mendelian loci or ratios of autosome to gender-determining loci. It is possible that gender is determined genetically by regions of the genome not sampled by the tested markers or by a complex of loci operating in an additive threshold manner or in an epistatic manner. It is also possible that gender is determined environmentally at an early zygote stage, canalizing gender expression.

McLetchie, D.N. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Biological Sciences; Tuskan, G.A. [Oak Ridge National Lab., TN (United States)

1994-12-31

358

Spectrophotometric determination of hydrazine.  

PubMed

Hydrazine is determined spectrophotometrically by forming the derivative 2,4-dinitrophenylhydrazine from 2,4-dinitrochlorobenzene. The formed dinitro derivative undergoes condensation reaction to form the hydrazone with p-dimethylaminobenzaldehyde (p-DAB). The resulting yellow colored product is stable in acidic medium and has a maximum absorption at 458 nm. The colour system obeys Beer's law in the range 0-7 microg of hydrazine in an overall volume of 25 mL. The molar absorptivity is calculated to be 8.1 x 10(4) L mol(-1)cm(-1) with a correlation coefficient of 0.998. The relative standard deviation is 1.7% (n=10) at 6 microg of hydrazine. Interferences due to foreign ions have been studied and the method has been applied for the determination of hydrazine in boiler feed water. PMID:18371842

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

2008-03-15

359

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

360

Fatigue sensitivity determination procedure  

US Patent & Trademark Office Database

A method for determining the sensitivity of the fatigue life of a structural component with respect to specific design parameters includes obtaining the stress profile for a structural component under random process establishing a relationship between the stress profile and the fatigue life of the structural component, developing the sensitivity of the fatigue life with respect to design parameters, optimizing the design of the structural component based upon the design parameters to which the fatigue life is most sensitive.

2004-03-09

361

POLAROGRAPHIC DETERMINATION OF RUTHENIUM  

Microsoft Academic Search

A method for the polarographic determination of ruthenium is discussed ; using basic sodium gluconate as the supporting electrolyte. The half-wave ; potential is --0.67v veisus the saturtred calomel electrode for 0.1 F sodium ; gluconate at pH 14. For these conditions the diffusion current constant, I, is ; 1.18 (maximum rather than average current). This constant is applicable for

D. T. Sawyer; R. J. Kula; A. L. Budd

1962-01-01

362

Interplanetary orbit determination  

NASA Technical Reports Server (NTRS)

The logistical aspects of orbit determination (OD) in the interplanetary phase of the Mariner Mars 1971 mission are described and the working arrangements for the OD personnel, both within the Navigation Team and with outside groups are given. Various types of data used in the OD process are presented along with sources of the data. Functional descriptions of the individual elements of the OD software and brief sketches of their modes of operation are provided.

Zielenbach, J. W.; Acton, C. H.; Born, G. H.; Breckenridge, W. G.; Chao, C. C.; Duxbury, T. C.; Green, D. W.; Jerath, N.; Jordan, J. F.; Mottinger, N. A.

1973-01-01

363

Standardization in allergen determination  

Microsoft Academic Search

An overview is given of sensitization and allergic reaction on food, along with minimal eliciting doses for selected allergens\\u000a (milk, egg, peanut), followed by the legislative situation in the European Community, the USA, Canada, Australia\\/New Zealand\\u000a and Japan. The main focus of the paper discusses methods for food allergen determination (chromatography, DNA-based, antibody-based)\\u000a and their limitations. Special emphasis is given

Markus Lacorn; Ulrike Immer

2010-01-01

364

Determination of a bottleneck  

US Patent & Trademark Office Database

A bottleneck determination method and system are disclosed. Sequential processes are defined and certain attributes for each process are quantified. These attributes may include a beginstock amount, a production amount, and a spoilage amount. Using the attributes, calculations are performed, and the results of these calculations are used to select processes that may be bottlenecks. Further calculations are performed with regard to this selected group, and the results of these further calculations are used to select a bottleneck process.

2010-05-04

365

REDUCED PROTECTIVE CLOTHING DETERMINATIONS  

SciTech Connect

This technical basis document defines conditions where reduced protective clothing can be allowed, defines reduced protective clothing, and documents the regulatory review that determines the process is compliant with the Tank Farm Radiological Control Manual (TFRCM) and Title 10, Part 835, of the Code of Federal Regulations (10CFR835). The criteria, standards, and requirements contained in this document apply only to Tank Farm Contractor (TFC) facilities.

BROWN, R.L.

2003-06-13

366

Gender determination using cheiloscopy  

PubMed Central

Background: Although lip prints have been used as an evidence for human identification in forensic science, there exists a doubt about its role in gender determination. Aims: The present study was designed for documenting common patterns, as well as their variation in the study population, with objective of evaluating uniqueness of the lip print pattern among the study population, as well as to evaluate the possibility of gender determination. Study Design: Two hundred and thirty five lip prints were collected from volunteers among out patients of Darshan Dental College and Hospital, as well as community dental care camps of rural areas around Udaipur. Materials and Methods: Lip prints were recorded with transparent overlay and transferred on to a bond paper. It was then photographed using a Canon EOS 55OD 16 mega pixel digital camera. Software Picasa 3.6 and Microsoft Picture Manager were used to digitally enhance the quality and magnify the image bearing the groove pattern. Lip prints were later analyzed. Statistical Analysis: Pearson chi square test was adopted for statistical analysis and probability (P value) was calculated. Conclusion: In our study, none of the lip prints were identical, thus confirming the role of lip prints in individual identification. Dots, reticular and complex patterns were significant in gender determination.

Padmavathi, B. N.; Makkad, Ramanpal Singh; Rajan, S. Y.; Kolli, Gopi Krishna

2013-01-01

367

(Determinating of the surface reactivity of coal powders). Final report. [4t-butylpyridine; 2,6-di-t-butylpyridine; 3,5-di-t-butylphenol; 2,6-di-t-butylphenol  

SciTech Connect

Techniques have been developed for study of the chemistry of the surface sites of coal powders. Conclusions of this study are as follows: (1) The surface of coal powders is heavily populated with acidic and basic sites with acid strengths on the order of phenol and with basic sites on the order of pyridine. (2) The surface population of acidic and basic sites is measurable by adsorption of t-butyl substituted organic acids and bases from solvents such as iso-octane, for the t-butyl group blocks penetration into the coal. (3) Flow calorimetric studies of the adsorption of t-butylated acid-base probes onto powdered coal allow accurate determination of the heats of adsorption and desorption. (4) Acid-base probes without the t-butyl group penetrate so deeply into coal powder particles that their desorption is quite incomplete. (5) Vacuum-oven drying of powdered coal reduces several-fold the amount of surface available for adsorption of acid-base probes. (6) The outer surface area of coal powders can be determined quantitatively by adsorption of t-butylated acid-base probes. The surface areas agree with those determined by gas adsorption with gases which do not hydrogen bond. (7) The adsorption of carbon dioxide into coal or any other polymer capable of acid-base interactions is shown to be a swelling phenomenon, unrelated to porosity. (8) Electrophoresis of coal powders in organic acids or bases is found to be a quick and easy way to determine if the surface has acidic or basic sites. (9) Electrophoresis of coal powders in acetonitrile provides a method of determining whether the surface of coal is predominantly acidic or basic; acidic coals are charged negatively and basic coals are charged positively. 11 refs., 5 figs., 12 tabs.

Fowkes, F.M.

1985-12-13

368

Satellite altitude determination uncertainties  

NASA Technical Reports Server (NTRS)

Satellite altitude determination uncertainties will be discussed from the standpoint of the GEOS-C satellite, from the longer range viewpoint afforded by the Geopause concept. Data are focused on methods for short-arc tracking which are essentially geometric in nature. One uses combinations of lasers and collocated cameras. The other method relies only on lasers, using three or more to obtain the position fix. Two typical locales are looked at, the Caribbean area, and a region associated with tracking sites at Goddard, Bermuda and Canada which encompasses a portion of the Gulf Stream in which meanders develop.

Siry, J. W.

1972-01-01

369

Determining nonmethane hydrocarbon  

NASA Astrophysics Data System (ADS)

In May 1987, an intercomparison exercise for the determination of nonmethane hydrocarbon gases in the marine atmosphere was conducted. A preliminary account of the results was presented at the 1987 AGU Fall Meeting (see the abstract “Non-Methane Hydrocarbons in the Remote Marine Atmsophere: Results of an Intercomparison Exercise,” in Eos, November 3, 1987, p. 1220).It has subsequently become evident that miscalculations occurred (in the conversion of units) that resulted in incorrect mixing ratios for some data sets as presented. A corrected report is in progress and will be published as soon as possible.

Carsey, Thomas P.

370

Mass determination of neutrinos  

NASA Technical Reports Server (NTRS)

A time-energy correlation method has been developed to determine the signature of a nonzero neutrino mass in a small sample of neutrinos detected from a distant source. The method is applied to the Kamiokande II (Hirata et al., 1987) and IMB (Bionta et al., 1987) observations of neutrino bursts from SN 1987A. Using the Kamiokande II data, the neutrino rest mass is estimated at 2.8 + 2.0, - 1.4 eV and the initial neutrino pulse is found to be less than 0.3 sec full width, followed by an emission tail lasting at least 10 sec.

Chiu, Hong-Yee

1988-01-01

371

Determining residential firewood consumption  

SciTech Connect

Household firewood use has become increasingly popular in the United States over the past few years. Significant problems remain in estimating firewood consumption. Methods of determining the amount of wood consumed vary from state to state. Units used for measuring firewood vary, but the cord remains the researcher's favorite. Factors used for converting other units, such as pickup truck loads to cords also vary. People who do not use firewood are less likely to respond to mailed surveys, resulting in potential overestimates of statewide consumption. This paper identifies some problems associated with estimating household firewood consumption and recommends methods of dealing with them.

Marsinko, A.P.C.; Phillips, D.R.; Cordell, H.K.

1984-07-01

372

ICESat Precision Orbit Determination  

NASA Astrophysics Data System (ADS)

Following the successful launch of the Ice, Cloud and land Elevation Satellite (ICESat) on January 13, 2003, 00:45 UTC, the GPS receiver on ICESat was turned on successfully on Jan. 17, 2003. High quality GPS data were collected since then to support Precision Orbit Determination (POD) activities. ICESat carries Geoscience Laser Altimeter System (GLAS) to measure ice-sheet topography and associated temporal changes, as well as cloud and atmospheric properties. To accomplish the ICESat science objectives, the position of the GLAS instrument in space should be determined with an accuracy of 5 cm and 20 cm in radial and horizontal components, respectively. This knowledge is acquired by the POD activities using the data collected by the GPS receiver on ICESat and the ground-based satellite laser ranging (SLR) data. It has been shown from pre-launch POD studies that the gravity model error is the dominant source of ICESat orbit errors. The predicted radial orbit errors at the ICESat orbit (600 km altitude) based on pre-launch gravity models, such as TEG-4 and EGM-96, are 7-15 cm. Performance of these gravity models and the recent gravity models from GRACE on ICESat POD were evaluated. The radial orbit accuracy is approaching 1-2 cm level with the GRACE gravity model. This paper also summarizes POD activities at Center for Space Research (CSR), which is responsible to generate ICESat POD products.

Rim, H.; Yoon, S.; Webb, C. E.; Kim, Y.; Schutz, B. E.

2003-12-01

373

Determination of Survivable Fires  

NASA Technical Reports Server (NTRS)

At NASA, there exists no standardized design or testing protocol for spacecraft fire suppression systems (either handheld or total flooding designs). An extinguisher's efficacy in safely suppressing any reasonable or conceivable fire is the primary benchmark. That concept, however, leads to the question of what a reasonable or conceivable fire is. While there exists the temptation to over-size' the fire extinguisher, weight and volume considerations on spacecraft will always (justifiably) push for the minimum size extinguisher required. This paper attempts to address the question of extinguisher size by examining how large a fire a crew member could successfully survive and extinguish in the confines of a spacecraft. The hazards to the crew and equipment during an accidental fire include excessive pressure rise resulting in a catastrophic rupture of the vehicle skin, excessive temperatures that burn or incapacitate the crew (due to hyperthermia), carbon dioxide build-up or other accumulation of other combustion products (e.g. carbon monoxide). Estimates of these quantities are determined as a function of fire size and mass of material burned. This then becomes the basis for determining the maximum size of a target fire for future fire extinguisher testing.

Dietrich, D. L.; Niehaus, J. E.; Ruff, G. A.; Urban, D. L.; Takahashi, F.; Easton, J. W.; Abbott, A. A.; Graf, J. C.

2012-01-01

374

Gears: Determining Angular Velocity  

NSDL National Science Digital Library

Students work as engineers and learn to conduct controlled experiments by changing one experimental variable at a time to study its effect on the experiment outcome. Specifically, they conduct experiments to determine the angular velocity for a gear train with varying gear ratios and lengths. Student groups assemble LEGO® MINDSTORMS® NXT robots with variously sized gears in a gear train and then design programs using the NXT software to cause the motor to rotate all the gears in the gear train. They use the LEGO data logging program and light sensors to set up experiments. They run the program with the motor and the light sensor at the same time and analyze the resulting plot in order to determine the angular velocity using the provided physics-based equations. Finally, students manipulate the gear train with different gears and different lengths in order to analyze all these factors and figure out which manipulation has a higher angular velocity. They use the equations for circumference of a circle and angular velocity; and convert units between radians and degrees.

AMPS GK-12 Program,

375

Determinants of Food Allergy  

PubMed Central

SUMMARY Much has been learned by identifying the molecules that can be recognized by IgE from patients with allergies. Increasingly, by correlating patterns of sensitization with clinical features, it has become possible to distinguish molecules responsible for primary sensitization (complete allergens) from those that are more likely cross-reactive targets. In the case of animal allergens, evolutionary distance seems to be an important factor in determining allergenicity. However, until more is understood regarding the mechanistic details of primary sensitization, including the participation of molecules that stimulate innate immune responses and the repertoire of T-cell antigens, molecules that may or may not themselves be important B-cell antigens, we will not be able to explain fundamental questions, such as why peanut allergy is more severe than soy allergy or why tick exposure is associated with clinically relevant sensitization to a carbohydrate epitope.

Masilamani, Madhan; Commins, Scott; Shreffler, Wayne

2012-01-01

376

Complexometric Determination of Calcium  

NASA Astrophysics Data System (ADS)

Ethylenediaminetetraacetate (EDTA) complexes with numerous mineral ions, including calcium and magnesium. This reaction can be used to determine the amount of these minerals in a sample by a complexometric titration. Endpoints in the titration are detected using indicators that change color when they complex with mineral ions. Calmagite and eriochrome black T (EBT) are such indicators that change from blue to pink when they complex with calcium and magnesium. In the titration of a mineral-containing solution with EDTA, the solution turns from pink to blue at the endpoint with either indicator. The pH affects a complexometric EDTA titration in several ways, and must be carefully controlled. A major application of EDTA titration is testing the hardness of water, for which the method described is an official one (Standard Methods for the Examination of Water and Wastewater, Method 2340C; AOAC Method 920.196).

Nielsen, S. Suzanne

377

Orbit Determination Toolbox  

NASA Technical Reports Server (NTRS)

The Orbit Determination Toolbox is an orbit determination (OD) analysis tool based on MATLAB and Java that provides a flexible way to do early mission analysis. The toolbox is primarily intended for advanced mission analysis such as might be performed in concept exploration, proposal, early design phase, or rapid design center environments. The emphasis is on flexibility, but it has enough fidelity to produce credible results. Insight into all flight dynamics source code is provided. MATLAB is the primary user interface and is used for piecing together measurement and dynamic models. The Java Astrodynamics Toolbox is used as an engine for things that might be slow or inefficient in MATLAB, such as high-fidelity trajectory propagation, lunar and planetary ephemeris look-ups, precession, nutation, polar motion calculations, ephemeris file parsing, and the like. The primary analysis functions are sequential filter/smoother and batch least-squares commands that incorporate Monte-Carlo data simulation, linear covariance analysis, measurement processing, and plotting capabilities at the generic level. These functions have a user interface that is based on that of the MATLAB ODE suite. To perform a specific analysis, users write MATLAB functions that implement truth and design system models. The user provides his or her models as inputs to the filter commands. The software provides a capability to publish and subscribe to a software bus that is compliant with the NASA Goddard Mission Services Evolution Center (GMSEC) standards, to exchange data with other flight dynamics tools to simplify the flight dynamics design cycle. Using the publish and subscribe approach allows for analysts in a rapid design center environment to seamlessly incorporate changes in spacecraft and mission design into navigation analysis and vice versa.

Carpenter, James R.; Berry, Kevin; Gregpru. Late; Speckman, Keith; Hur-Diaz, Sun; Surka, Derek; Gaylor, Dave

2010-01-01

378

Significant Radionuclides Determination  

SciTech Connect

The purpose of this calculation is to identify radionuclides that are significant to offsite doses from potential preclosure events for spent nuclear fuel (SNF) and high-level radioactive waste expected to be received at the potential Monitored Geologic Repository (MGR). In this calculation, high-level radioactive waste is included in references to DOE SNF. A previous document, ''DOE SNF DBE Offsite Dose Calculations'' (CRWMS M&O 1999b), calculated the source terms and offsite doses for Department of Energy (DOE) and Naval SNF for use in design basis event analyses. This calculation reproduces only DOE SNF work (i.e., no naval SNF work is included in this calculation) created in ''DOE SNF DBE Offsite Dose Calculations'' and expands the calculation to include DOE SNF expected to produce a high dose consequence (even though the quantity of the SNF is expected to be small) and SNF owned by commercial nuclear power producers. The calculation does not address any specific off-normal/DBE event scenarios for receiving, handling, or packaging of SNF. The results of this calculation are developed for comparative analysis to establish the important radionuclides and do not represent the final source terms to be used for license application. This calculation will be used as input to preclosure safety analyses and is performed in accordance with procedure AP-3.12Q, ''Calculations'', and is subject to the requirements of DOE/RW-0333P, ''Quality Assurance Requirements and Description'' (DOE 2000) as determined by the activity evaluation contained in ''Technical Work Plan for: Preclosure Safety Analysis, TWP-MGR-SE-000010'' (CRWMS M&O 2000b) in accordance with procedure AP-2.21Q, ''Quality Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities''.

Jo A. Ziegler

2001-07-31

379

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

380

Determinants of expression variability.  

PubMed

The amount of tissue-specific expression variability (EV) across individuals is an essential characteristic of a gene and believed to have evolved, in part, under functional constraints. However, the determinants and functional implications of EV are only beginning to be investigated. Our analyses based on multiple expression profiles in 41 primary human tissues show that a gene's EV is significantly correlated with a number of features pertaining to the genomic, epigenomic, regulatory, polymorphic, functional, structural and network characteristics of the gene. We found that (i) EV of a gene is encoded, in part, by its genomic context and is further influenced by the epigenome; (ii) strong promoters induce less variable expression; (iii) less variable gene loci evolve under purifying selection against copy number polymorphisms; (iv) genes that encode inherently disordered or highly interacting proteins exhibit lower variability; and (v) genes with less variable expression are enriched for house-keeping functions, while genes with highly variable expression tend to function in development and extra-cellular response and are associated with human diseases. Thus, our analysis reveals a number of potential mediators as well as functional and evolutionary correlates of EV, and provides new insights into the inherent variability in eukaryotic gene expression. PMID:24435799

Alemu, Elfalem Y; Carl, Joseph W; Corrada Bravo, Héctor; Hannenhalli, Sridhar

2014-04-01

381

Determinants of expression variability  

PubMed Central

The amount of tissue-specific expression variability (EV) across individuals is an essential characteristic of a gene and believed to have evolved, in part, under functional constraints. However, the determinants and functional implications of EV are only beginning to be investigated. Our analyses based on multiple expression profiles in 41 primary human tissues show that a gene’s EV is significantly correlated with a number of features pertaining to the genomic, epigenomic, regulatory, polymorphic, functional, structural and network characteristics of the gene. We found that (i) EV of a gene is encoded, in part, by its genomic context and is further influenced by the epigenome; (ii) strong promoters induce less variable expression; (iii) less variable gene loci evolve under purifying selection against copy number polymorphisms; (iv) genes that encode inherently disordered or highly interacting proteins exhibit lower variability; and (v) genes with less variable expression are enriched for house-keeping functions, while genes with highly variable expression tend to function in development and extra-cellular response and are associated with human diseases. Thus, our analysis reveals a number of potential mediators as well as functional and evolutionary correlates of EV, and provides new insights into the inherent variability in eukaryotic gene expression.

Alemu, Elfalem Y.; Carl, Joseph W.; Corrada Bravo, Hector; Hannenhalli, Sridhar

2014-01-01

382

Indirect shearwave determination  

SciTech Connect

A method is described of estimating parameters of shear waves included in acoustic waves arriving sequentially at points spaced vertically along the length of a borehole. The method consists of the steps of: (a) generating acoustic energy in the borehole, (b) receiving the acoustic energy at each of the points after refraction, reflection and direct transmission through and along a formation adjacent the borehole, (c) establishing a window of known length with a known movement between adjacent receiving points, (d) positioning the window along the composite wave relative to the estimated arrival of a selected guided acoustic wave, (e) multiplying the energy received at each point by the window, (f) generating the Fourier transform of that portion of received guided wave energy multiplied by the window, to produce complex signals in the frequency domain, (g) determining the cross-spectral magnitude and phase for pairs of signals from adjacent receiving points, (h) computing the phase velocity ..cap alpha.. from the phase at each frequency, (i) scanning the cross-spectral magnitudes for a peak in a selected frequency range and identifying the frequency at which the peak occurs, (j) selecting from the phase velocity ..cap alpha.. versus frequency a value of guided wave phase velocity ..cap alpha../sub S/ at the identified frequency, (k) estimating the ratio of Lame constants ..mu../sub 2/ and lambda/sub 1/ in accordance with the expression.

Ingram, J.D.; Murray, J.L.

1986-03-11

383

VSOP-2 Orbit Determination  

NASA Astrophysics Data System (ADS)

Precise orbit determination (POD) is a key factor to enable phase referencing observations with Astro-G. A POD accuracy of 30 cm is required for efficient X-band phase referencing observations, accuracy of 6 cm for K-band observations, and accuracy of 3 cm for Q-band observations. For the POD, Astro-G will be equipped with a GPS/Galileo receiver and a SLR (Satellite Laser Ranging) retroreflector array. Four POD antennas will be equipped on four sides of the satellite body, to cover all directions. The SLR will be used as a complement to the GPS at middle-to-high altitude. Because the refroreflector array should always face to the Earth direction, it will be set up on the Ka-link antenna gimbal. The most significant perturbing force for the Astro-G is solar radiation pressure (SRP). The reflectivity of each surface component should be preliminary measured in detail to model the SRP. The estimated achievable POD accuracy at apogee is 10 ˜ 30 cm in nominal case. Phase referencing observations in K- or Q-band can be performed if the enough amount of SLR tracking data can be obtained at high altitudes.

Takeuchi, H.; VSOP-2 Orbit Determination Sub-Working Group

2009-08-01

384

Social determinants of disease.  

PubMed

The primary purpose for identifying psychosocial risk factors is to prevent disease and disease complications. For 30 years, we have been doing research in this field and have been successful in identifying such risk factors as Type A behavior, social isolation, stressful life events, and various psychological patterns. However, our success in using this information to help prevent disease has been much more limited. One reason for this limited success is that we have focused virtually all of our attention on the study of individuals and almost no attention on the social environment within which people live. There are two major limitations of such a one-to-one approach: it is difficult for people to change their behavior and their life situation and even if some people do change, others enter the "at risk" population because no action has been taken to change those forces in society that stimulated the problem in the first place. In discussing the social determinants of disease, it is important that we develop a new approach that permits us to study not only individuals but also the social environment. An example of this approach is provided by researchers who were successful in preventing infectious diseases. The work of these researchers focused not on clinical entities or on individuals but on the environment. This resulted in a disease classification system that included concepts such as air-borne, food-borne, water-borne, and vector-borne diseases. We have no such system for the study of non-infectious diseases. Considerable data already are available to help us to think about such a new classification system.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3662409

Syme, S L

1987-01-01

385

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

386

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

387

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.

388

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

389

The ACS Virgo Cluster Survey XVI. Selection Procedure and Catalogs of Globular Cluster Candidates  

NASA Astrophysics Data System (ADS)

We present catalogs of globular cluster candidates for the 100 galaxies of the Advanced Camera for Surveys Virgo Cluster Survey, a large program to carry out imaging of early-type members of the Virgo Cluster using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. We describe the procedure used to select bona fide globular cluster candidates out of the full list of detections based on model-based clustering methods with the use of expected contamination catalogs constructed using blank field observations and which are customized for each galaxy. We also present the catalogs of expected contaminants for each of our target galaxies. For each detected source we measure its position, magnitudes in the F475W (? Sloan g) and F850LP (? Sloan z) bandpasses, and half-light radii by fitting point-spread function convolved King models to the observed light distribution. These measurements are presented for 20,375 sources, of which 12,763 are likely to be globular clusters. Finally, we detail the calculation of the aperture corrections adopted for the globular cluster photometry. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Jordán, Andrés; Peng, Eric W.; Blakeslee, John P.; Côté, Patrick; Eyheramendy, Susana; Ferrarese, Laura; Mei, Simona; Tonry, John L.; West, Michael J.

2009-01-01

390

LIBROS DE MÚSICA PARA EL NUEVO MUNDO EN EL SIGLO XVI  

Microsoft Academic Search

En el Archivo General de Indias de Sevilla se conserva el expediente de un pleito que enfrentó a Alonso Pérez, copista y clérigo de Medina del Campo, y a Francisco Fernández de Córdoba, conocido impresor de Valladolid, en activo entre 1541 y 1570. Cada uno de los litigantes pretendía los derechos de publicación de los cantorales para las Indias, en

Emilio Ros-Fábregas

2001-01-01

391

Follow-Up Study of 1986 Harper Career Alumni. Volume XVI, No. 9.  

ERIC Educational Resources Information Center

As part of an ongoing evaluation of the career programs at Illinois' William Rainey Harper College (WRHC), a follow-up study of 1986 program graduates was conducted and results were compared with previous years. Questionnaires were sent to 491 students who earned 48 or more hours during the 1985-86 academic year at WRHC. Study findings, based on a…

Lucas, John A.

392

Newsletter for Research in Mental Health and Behavioral Sciences, Volume XVI, Number 3.  

National Technical Information Service (NTIS)

A comparison of personality characteristics, body image and social attitudes of organ transplant donors and nondonors, as well as a description of changes in human tissue donation attitudes are included in this issue. Personal values of alcoholics and add...

1974-01-01

393

Follow-Up Study of Former Students of the Data Processing Program. Volume XVI, No. 3.  

ERIC Educational Resources Information Center

In spring 1987, a follow-up survey was conducted of former William Rainey Harper College (WRHC) students who had taken five or more data processing courses at the college between 1980 and 1986. The survey focused on the students' employment status and educational intent while attending WRHC, their present employment situation, and their evaluation…

Rilki, Ernest; Lucas, John A.

394

Infrared technology XVI; Proceedings of the Meeting, San Diego, CA, July 11-13, 1990  

NASA Astrophysics Data System (ADS)

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, Irving J.

1990-11-01

395

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.

396

Diffuse idiopathic skeletal hyperostosis in the Medici, Grand Dukes of Florence (XVI century)  

PubMed Central

Diffuse idiopathic skeletal hyperostosis (DISH) is a common systemic disorder characterised by the ossification of the anterior longitudinal spinal ligament involving at least three contiguous vertebrae and by diffuse extraspinal enthesopathies. The condition is associated with the male sex and with advanced age; its aetiology is uncertain, but seems to be related to obesity and diabetes. The most recent studies in archaeological series demonstrated a relation between high social status and the incidence of DISH. The present study examines two cases of DISH found amongst the members of the Medici family buried in the Basilica of San Lorenzo in Florence. The skeletons of the Grand Dukes Cosimo I (1519–1574) and his son Ferdinand I (1549–1609) showed the typical features of the condition. This result is related to the obesity of the Grand Dukes, attested by the written and artistic sources, and to the protein-based alimentation demonstrated by a paleonutritional study, thus furnishing further evidence to the significance of DISH as a life style.

Giusiani, Sara; Fornaciari, Antonio; Villari, Natale; Vitiello, Angelica; Fornaciari, Gino

2009-01-01

397

Vinyl ethers containing an epoxy group. XVI. Reaction of glycidol vinyloxyethyl ether with acetals  

SciTech Connect

In order to obtain branched acetals with epoxide groups (prospective monomers and intermediates) the authors investigated the reaction of acetaldehyde diethyl and di(1,1,3-trihydrotetrafluoropropyl) acetals with glycidol vinyloxyethyl ether. The addition of acetals to vinyl epoxy ethers was realized, and the first representative of compounds of this type, i.e., 9-glycidyloxy-6-ethoxy-4-methyl-3,7-dioxanonane, was obtained. It was also impossible to add a fluoroacetal to butyl vinyl ether (0.08-1.00 wt. % of catalyst CF/sub 3/COOH, BF/sub 3//times/ OEt/sub 2/, 20-80/degree/C, 0.5-3 h).

Nedolya, N.A.; Khil'ko, M.Ya.; Trofimov, B.A.; Sigalov, M.V.

1988-10-10

398

Scientia Paedagogica Experimentalis. International Journal of Experimental Research in Education. XVI, 1.  

ERIC Educational Resources Information Center

Seven papers on experimental research topics in education, written by educators of various nationalities, are compiled in this volume. The first paper, written in French with an English summary, explores the ability of the teacher to exercise an indirect influence over student behavior and the systematic training of certain teacher behaviors to…

Verbist, R., Ed.; And Others

1979-01-01

399

The Iron Project and the RMAX Project: Transitions in Fe XV, Fe XVI, and Astrophysical Applications  

Microsoft Academic Search

While the Iron Project is involved in scattering and radiative atomic processes of iron and iron-peak elements, the Rmax Project aims at the X-ray spectroscopy of astrophysical objects. Under the Iron Project, the oscillator strengths and radiative decay rates for fine structure transitions going up to n=10 and l=9 are obtained for magenesium like Fe XV and sodium like Fe

Maximiliano Montenegro; Sultana Nahar; Anil Pradhan; Chiranjib Sur; Justin Oelgoetz

2007-01-01

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

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

Federal Register 2010, 2011, 2012, 2013

...basis. E. Work-Related Stress 1. Working involves many factors and demands that can...experience stress related to the demands of...08 based on either BMI. 4. An inconsistency...a specific work-related activity; for...

2011-09-12

402

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

403

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

404

Investigations on fungicides. XVI. Natural resistance of plant roots to fungal pathogens.  

PubMed

Uninoculated roots of pea (Pisum sativum) and French bean (Phaseolus vulgaris) have been shown to exude a number of antifungal compounds when grown in a non-sterile aqueous aerated medium. These have been identified and their possible importance in relation to disease resistance is discussed. PMID:19280789

Burden, R S; Rogers, P M; Wain, R L

1974-09-01

405

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

406

Amino acids and peptides. XVI. Synthesis of a tetrapeptide sequence (A9-A12) of glucagon  

Microsoft Academic Search

A synthesis of the tetrapeptide sequence As-Ag of glucagon is described that employs various blocking groups, coupling procedures, and routes. The threonyl-phenylalanyl-threonyl-seryl sequence A5-A8 in the hyperglycemic hormone, glucagon (Foa and Galansino, 1962), has been prepared by three dif- ferent groups within the past four years (Beyerman and Bontekoe, 1964; Schroder and Gibian, 1962; Wunsch and Wendleberger, 1964). In connection

EARLE R. CALEY; LOWELL W. SHANK; BRIAN O. HANDFORD

1968-01-01

407

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

408

Newsletter for Research in Mental Health and Behavioral Sciences, Volume XVI, Number 2.  

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 specific patients and the prog...

1974-01-01

409

Project VASSEL XVI. Comparison of Predicted and Measured Propagation Loss vs Range.  

National Technical Information Service (NTIS)

This report develops a methodology for analytically comparing underwater sound propagation loss measurements with predictions made by a propagation loss model. The method is employed to compare measurements during an at sea experiment (VASSEL XV/FIXWEX) w...

J. E. Fairchild

1969-01-01

410

The Extragalactic Distance Scale Key Project. XVI. Cepheid Variables in an Inner Field of M101  

NASA Technical Reports Server (NTRS)

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.

Stetson, P. B.; Saha, A.; Ferrarese, L.; Rawson, D. M.; Ford, H. C.; Freedman, W. L.; Graham, J. A.; Harding, P.; Han, M.; Hill, R. J.; Hoessel, J. G.; Huchra, J. P.; Hughes, S. M.; Illingworth, G. D.; Kennicutt, R. C., Jr.; Madore, B. F.; Mould, J. R.; Phelps, R. L.; Sakai, S.; Silbermann, N. A.; Turner, A.

1998-01-01

411

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

412

Cryogenic laser calorimetry for impurity analysis  

NASA Technical Reports Server (NTRS)

The results of a one-year effort to determine the applicability of laser-calorimetric spectroscopy to the study of deep-level impurities in silicon are presented. Critical considerations for impurity analysis by laser-calorimetric spectroscopy are discussed, the design and performance of a cryogenic laser calorimeter is described, and measurements of background absorption in high-purity silicon are presented.

Swimm, R. T.

1985-01-01

413

Indirect polarographic determination of arsenic.  

PubMed

A method for determination of arsenic(V) in the range between 1 x 10(-7) and 1.2 x 10(-6)M has been developed. These levels are reached by means of the multiplication factor yielded by use of 12-molybdoarsenic acid and the great sensitivity of polarographic determination of the Mo(VI) in the heteropoly acid. The procedure has been successfully applied to determination of arsenic in copper alloys, after selective extraction of phosphorus. PMID:18964945

Barrado, E; Castrillejo, Y; Del Real, E; Pardo, R; Batanero, P S

1990-03-01

414

Determination of Rogowski Coil Constant  

Microsoft Academic Search

Method of determination of Rogowski coil (RC) constant at 50 Hz frequency is described in the article. The RC constant determining dependence between output voltage and measured current is checked and also a phase displacement of these two quantities is measured. Analysis of measurement uncertainties is also presented.

K. Draxler; R. Styblikova

2006-01-01

415

Uncertainty determination in QXAFS measurements  

NASA Astrophysics Data System (ADS)

Measured uncertainties in QEXAFS measurements are determined using an oversampling technique. The output of an ionization chamber is read through a current amplifier using a sampling analog to digital converter. By oversampling the data, uncertainties are determined simultaneously with data collection. .

Quintana, J. P. G.

2000-06-01

416

Method of Determining Insect Infestation.  

National Technical Information Service (NTIS)

This invention relates to a method of determining the degree of insect infestation in foodstuffs by determining the uric acid content of a sample by measuring the intensity of its fluorescence in an acetate buffer and comparing uric acid content with know...

L. W. Smith

1981-01-01

417

Kinematic Precise Orbit Determination for Gravity Field Determination  

Microsoft Academic Search

In this paper we first present approaches and results in precise orbit determination (POD) for satellites in Low Earth Orbit\\u000a (LEO) based on one or two frequency GPS measurements and, secondly, we focus on the relations between kinematic POD and gravity\\u000a field determination. Using GPS measurements of the CHAMP satellite we show that it is possible to estimate kinematic positions

D. Švehla; M. Rothacher

418

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

419

Method of determining glass durability  

DOEpatents

A process 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.

Jantzen, Carol Maryanne (Aiken, SC); Pickett, John Butler (Aiken, SC); Brown, Kevin George (Augusta, GA); Edwards, Thomas Barry (Aiken, SC)

1998-01-01

420

Variationally determined multipole Cauchy moments  

SciTech Connect

The hydrodynamic variational method for obtaining dynamic multipole polarizabilities is extended to determine multipole Cauchy moments. The hydrodynamic functional is replaced by an equivalent series of functionals, obtained by expanding the first-order functions in power series of the applied frequency. As an application of the method, multipole Cauchy moments for the ground states of atomic hydrogen and helium are determined by solving variationally the set of functionals. The resulting moments are then used to construct Pade approximants, from which long-range dispersion coefficients are determined.

Bartolotti, L.J.

1980-10-15

421

Thermodynamics of Molecular Interactions in Coal Liquids: Progress Report for the Period July-December 1986.  

National Technical Information Service (NTIS)

The objects of this study were to determine the thermodynamics associated with the interactions among the components of a model coal liquid by calorimetric techniques, to determine the vapor-liquid equilibria of mixtures of the model compounds and, based ...

D. J. Eatough L. D. Hansen J. J. Christensen E. A. Lewis

1986-01-01

422

Method for Determining Artillery Position  

NASA Technical Reports Server (NTRS)

A method is described for determinig artillery positions. Two groups of four closely spaced microphones are placed at known positions, and radio bearings are determined by projectile flight time differences of muzzle blasts. The advantages of the method are discussed.

Fischer, Johannes; Meuser, Wilfried

1988-01-01

423

Functionality Determination of Binder Prepolymers.  

National Technical Information Service (NTIS)

This report is the seventh Quarterly Progress Report discussing research aimed at the development of accurate and reasonably fast test procedures to determine the functionality and functionality distribution of prepolymers of interest to the Air Force. Fu...

A. H. Muenker B. E. Hudson

1968-01-01

424

What Determines Gender in Humans?  

NSDL National Science Digital Library

In this activity students examine karyotypes from five individuals to try to identify which chromosomes determine gender in humans. This activity is also a good illustration of meiotic non-disjunction.

Cooper, Scott

425

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

426

Atmospheric Turbulence Field Parameters Determination.  

National Technical Information Service (NTIS)

A Newton-Raphson least squares percentage error method is developed for the determination of atmospheric turbulence field parameters. A correction function is proposed to deemphasize the effects of data points with low statistical confidence. The method i...

D. J. Golden J. N. Garrison R. L. Neulieb

1972-01-01

427

Indirect complexometric determination of chromate.  

PubMed

Chromate is determined indirectly, by precipitation as silver chromate, dissolution of the precipitate in potassium tetracyanonickelate, and titration of the liberated nickel with EDTA, with Murexide as indicator. PMID:18961382

de Sousa, A

1973-10-01

428

Determinants of heart rate variability  

Microsoft Academic Search

Objectives. This study sought to examine clinical determinants of heart rate variability and to report normative reference values for eight heart rate variability measures.Background. Although the clinical implications of heart rate variability have been described, clinical determinants and normative values of heart rate variability measures have not been studied systematically in a large community-based population.Methods. The first 2 h of

Hisako Tsuji; Ferdinand J. Venditti; Emily S. Manders; Jane C. Evans; Martin G. Larson; Charles L. Feldman; Daniel Levy

1996-01-01

429

Gender determination of avian embryo  

SciTech Connect

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

430

Sex determination in flowering plants.  

PubMed Central

In many ways, plants offer unique systems through which to study sex determination. Because the production of unisexual flowers has evolved independently in many plant species, different and novel mechanisms may be operational. Hence, there is probably not one unifying mechanism that explains sex determination in plants. Advances in our understanding of sex determination will come from the analysis of the genetics, molecular biology, and biochemistry of genes controlling sexual determination in plants. Several excellent model systems for bisexual floral development (Arabidopsis and Antirrhinum), monoecy (maize), and dioecy (Silene, asparagus, and mercury) are available for such analyses. The important questions that remain concern the mechanism of action of sex determination genes and their interrelationship, if any, with homeotic genes that determine the sexual identity of floral organ primordia. At the physiological level, the connection between hormone signaling and sexuality is not well understood, although significant correlations have been discovered. Finally, once the genes that regulate these processes are identified, cloned, and studied, new strategies for the manipulation of sexuality in plants should be forthcoming.

Dellaporta, S L; Calderon-Urrea, A

1993-01-01

431

Molecular genetics of sex determination.  

PubMed

In humans, the choice between male or female development is genetically determined. Sex determination take place when the bipotential embryonic gonad becomes either testis or ovary. This process is directed by genes that have been discovered by genetic analysis of sex-reversed patients and confirmed by knockout experiments in mice. The testis-determining pathway is better known than the ovary pathway. SRY, a gene located on the Y chromosome, triggers a complex genetic cascade leading to testicular differentiation. In this cascade, two genes play a crucial role in male differentiation, SOX9 and FGF9, which contribute to testicular cord formation. However, only a minority of 46,XY sex-reversed patients can be explained by mutations in known genes such as SRY, SOX9, WTI, and SF1, suggesting that other genes influencing sex determination are yet to be discovered. In females, some rare genes that induce ovarian failure or female-to-male sex reversal have been found through gene-targeted inactivation in mice or positional cloning of mutations in humans and goats. In both sexes, genetic analysis of sex-reversed individuals (XX males, XX and XY hermaphrodites, and XY with complete or partial dysgenesis) remains an approach of choice to isolate new genes involved in sex determination. PMID:12428196

Cotinot, Corinne; Pailhoux, Eric; Jaubert, Francis; Fellous, Marc

2002-08-01

432

Lunar Prospector Orbit Determination Results  

NASA Technical Reports Server (NTRS)

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 correction maneuvers during the translunar cruise followed by three lunar orbit insertion burns. This paper will detail the cislunar orbit determination accuracy and the real-time assessment of the cislunar trajectory correction and lunar orbit insertion maneuvers. The non-spherical gravity model of the Moon is the primary influence on the mapping orbit determination accuracy. During the first two months of the mission, the GLGM-2 lunar potential model was used. After one month in the mapping orbit, a new potential model was developed that incorporated LP Doppler data. This paper will compare and contrast the mapping orbit determination accuracy using these two models. LP orbit support also includes a new enhancement - a web page to disseminate all definitive and predictive trajectory and mission planning information. The web site provides definitive mapping orbit ephemerides including moon latitude and longitude, and four week predictive products including: ephemeris, moon latitude/longitude, earth shadow, moon shadow, and ground station view periods. This paper will discuss the specifics of this web site.

Beckman, Mark; Concha, Marco

1998-01-01

433

A Predictive Framework for Determining How Journalists Determine News.  

ERIC Educational Resources Information Center

To determine how to articulate a concrete definition of the substance of the journalist's occupation, this paper offers a propositional framework of news value based on Kurt Lewin's gatekeeper model. First, the paper follows the established suggestion that news decisions are best studied from a gatekeeping perspective or that "news is whatever…

Gaudino, James L.