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1

A calorimetric method to determine water activity  

NASA Astrophysics Data System (ADS)

A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg-1 to 3 mol kg-1 and seven saturated aqueous salt solutions (LiCl, MgCl2, NaBr, NaCl, KCl, KNO3, and K2SO4) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities.

Björklund, Sebastian; Wadsö, Lars

2011-11-01

2

Calorimetric determination of the enzyme activity immobilised on macroporous glass membranes  

Microsoft Academic Search

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

Hagen Graebner; Regina Hüttl; Gert Wolf

2002-01-01

3

Calorimetric determinations and theoretical calculations of polymorphs of thalidomide  

NASA Astrophysics Data System (ADS)

The analysis of the thermograms of thalidomide obtained for the two reported polymorphs ? and ? by differential scanning calorimetry (DSC) shows some inconsistencies that are discussed in the present work. The conception of a new polymorph form, named ? ?, allowed us to explain the observed thermal behavior more satisfactorily. This new polymorph shows enantiotropy with both ? and ? polymorphs, reflected in the unique endotherm obtained in the DSC-thermograms, when a heating rate of 10 °C/min is applied. Several additional experiments, such as re-melting of both polymorph forms, showed that there is indeed a new polymorph with an endotherm located between the endotherms of ? and ?. IR, Raman, and powder X-ray permit us to characterize the isolated compound, resulting from the re-melting of both polymorph forms. Mechanical calculations were performed to elucidate the conformations of each polymorph, and ab initio quantum chemical calculations were performed to determine the energy of the more stable conformers and the spatial cell energy for both polymorphs ? and ?. These results suggested a possible conformation for the newly discovered polymorph ? ?.

Lara-Ochoa, F.; Pérez, G. Espinosa; Mijangos-Santiago, F.

2007-09-01

4

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

5

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

NASA Astrophysics Data System (ADS)

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

Ornellas, D. L.

1982-04-01

6

Calorimetric determination of fragility in glass forming liquids: T(f) 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

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

8

Thermodynamic study of rhodamine 123-calf thymus DNA interaction: determination of calorimetric enthalpy by optical melting study.  

PubMed

In this paper, the interaction of rhodamine123 (R123) with calf thymus DNA has been studied using molecular modeling and other biophysical methods like UV-vis spectroscopy, fluoremetry, optical melting, isothermal titration calorimetry, and circular dichroic studies. Results showed that the binding energy is about -6 to -8 kcal/mol, and the binding process is favored by both negative enthalpy change and positive entropy change. A new method to determine different thermodynamic properties like calorimetric enthalpy and heat capacity change has been introduced in this paper. The obtained data has been crossed-checked by other methods. After dissecting the free-energy contribution, it was observed that the binding was favored by both negative hydrophobic free energy and negative molecular free energy which compensated for the positive free energies due to the conformational change loss of rotational and transitional freedom of the DNA helix. PMID:25383921

Masum, Abdulla Al; Chakraborty, Maharudra; Pandya, Prateek; Halder, Umesh Chandra; Islam, Md Maidul; Mukhopadhyay, Subrata

2014-11-20

9

Water calorimetric determination of absorbed dose by 280 kVp orthovoltage X-rays.  

PubMed

The absorbed dose to water from 280 kVp orthovoltage X-rays was determined by a water calorimeter and compared with that determined by an ionization chamber. X-ray qualities of three different filtrations were investigated: they were characterized by 0.57, 0.695 and 1.76 mm of copper half value layers (HVL). The absorbed dose determined by the calorimeter is found higher by 7-9% than that by an ionization chamber. This difference was greater by 4% than that observed for a 60Co beam with the same two detectors. PMID:4081114

Kubo, H

1985-11-01

10

The Silver-Nickel Interfacial Enthalpy Determined by Magnetic and Calorimetric Measurements  

Microsoft Academic Search

A new method for the determination of the average interfacial enthalpy, sigma_sp{A -B}{H}, between unlike phases is presented. A differential scanning calorimeter is used to measure the heat released during precipitation of a superparamagnetic phase from a supersaturated solid solution. The volume fraction distribution of the precipitated phase is determined by maximum entropy modeling of the magnetization, measured to ultra-high

Howard Gordon Zolla

1995-01-01

11

Determination of the activation energy spectrum of structural relaxation in metallic glasses using calorimetric and shear modulus relaxation data  

NASA Astrophysics Data System (ADS)

We consider two methods for reconstruction of the activation energy spectra of structural relaxation from calorimetric and shear modulus relaxation data. The methods are based on the assumption that structural relaxation of metallic glasses can be understood as a relaxation change of the concentration of frozen-in defects similar to dumbbell interstitials (interstitialcies) in simple crystals. For three Pd- and Zr-based glasses taken as an example, it is shown that both methods give nearly the same results. We calculated a decrease of the defect concentration and showed that the heat of structural relaxation per defect for all three glasses practically coincides with the theoretical value of the interstitialcy formation enthalpy.

Tsyplakov, A. N.; Mitrofanov, Yu. P.; Makarov, A. S.; Afonin, G. V.; Khonik, V. A.

2014-09-01

12

Use of the BIPM calorimetric and ionometric standards in megavoltage photon beams to determine Wair and Ic  

NASA Astrophysics Data System (ADS)

The BIPM graphite calorimeter standard for absorbed dose to water has been used in conjunction with an ionization chamber of known volume and with Monte Carlo simulations of these arrangements to determine the value for Wair in 60Co radiation and in accelerator photon beams up to 25 MV. The results show no evidence for a variation in Wair at the 0.2% level over this energy range. Taking the constancy of Wair as established, the best estimate is Wair = 34.03 eV with a standard uncertainty of 0.21%. Consistent with this analysis, and assuming the use of the grain density in evaluating the stopping power of graphite, is the value Ic = 81.1 eV for the mean excitation energy for graphite, with standard uncertainty 1.8 eV.

Burns, D. T.; Picard, S.; Kessler, C.; Roger, P.

2014-03-01

13

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

14

[Could phimosis have been the cause of sexual difficulties and delayed fertility of Louis XVI (1754-1793)?].  

PubMed

The great majority of historians agree that the marriage of Louis XVI and Marie-Antoinette was only consumated seven years after the official ceremony. This delay could have been due to a genital malformation (phimosis) of Louis XVI, a strict religious education, a traumatic childhood and the young age of the two spouses, factors that may have inhibited their sexuality. In this article, the authors try to determine whether Louis XVI was able to overcome his sexual difficulties following an operation (circumcision) or as a result of spontaneous cure. PMID:11980007

Androutsos, Georges

2002-02-01

15

PREFACE: Symmetries in Science XVI  

NASA Astrophysics Data System (ADS)

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

2014-10-01

16

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

E-print Network

Context: The commonly used extinction laws of Cardelli et al. (1989) have limitations that, among other issues, hamper the determination of the effective temperatures of O and early B stars from optical+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+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+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 uncertain...

Apellániz, J Maíz; 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

2014-01-01

17

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

18

Gamma-ray measurements for simultaneous calorimetric assay  

SciTech Connect

Gamma-ray measurements obtained in the course of developing a simultaneous calorimetric assay system are described. Gamma-ray measurements of the isotopic composition of six, well-characterized plutonium oxide samples were obtained while the samples were in the calorimeter. These samples represent a range of plutonium masses from 19 to 231 g and two isotopic compositions. The values of effective specific power determined from the gamma-ray measurements agree with the values determined from destructive assay.

Rakel, D.A.

1982-03-02

19

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

20

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

21

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

22

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

23

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

Microsoft Academic Search

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

V. Hoff; S CORRERA

1995-01-01

24

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

PubMed

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

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

2001-03-19

25

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

26

Fast Electron Thermometry for Ultrasensitive Calorimetric Detection  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

27

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

28

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

29

Effect of chilling on calorimetric responses of dormant vegetative apple buds  

Microsoft Academic Search

Chilling exposure is important in apple buds to overcome dormancy. The objective of this work was to determine the effect of different chilling treatments on apple bud calorimetric responses. One-year-old Golden Delicious trees were kept in a controlled temperature chamber at 4°C for up to 1600h. At 200h intervals, five trees were transferred to forcing conditions at 25°C. Isothermal calorimetry

A. A Gardea; E Carvajal-Millán; J. A Orozco; V. M Guerrero; J Llamas

2000-01-01

30

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

31

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

NASA Astrophysics Data System (ADS)

Spacecraft often rely 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.

2009-01-01

32

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

Federal Register 2010, 2011, 2012, 2013

...XVI: Evaluating Cases Involving Drug Addiction and Alcoholism (DAA) AGENCY: Social...for how we consider whether ``drug addiction and alcoholism'' (DAA) is material...Titles II and XVI: Evaluation of Drug Addiction and Alcoholism. This SSR obsoletes...

2013-02-20

33

The CALorimetric Electron Telescope, CALET, Mission  

NASA Astrophysics Data System (ADS)

We are developing the CALorimetric Electron Telescope, CALET, mission for the Japanese Experiment Module Exposed Facility, JEM-EF, of the International Space Station. Major scientific objectives are to search for nearby cosmic ray sources and dark matter by carrying out a precise measurement of the electrons in GeV 20 TeV and the gamma-rays in 20 MeV TeV. CALET has a unique capability to observe electrons and gamma-rays over 1 TeV since the hadron rejection power is more than 105 and the energy resolution better than a few percent over 100 GeV. The detector consists of an Imaging Calorimeter (IMC) with scintillating fiber belts and tungsten plates, a Total Absorption Calorimeter (TASC) with BGO logs, a Silicon Pixel Array (SIA) and a Scintillator Anti-Coincidence System (SACS). CALET has also a capability to measure protons and nuclei in 10 GeV 1000 TeV, and will have a function to monitor solar activity and gamma-ray bursts with additional instruments. The phase A study has started on a schedule of launch in 2013 by H-II Transfer Vehicle (HTV) for 5 years observation.

Torii, Shoji

34

Fructose-selective calorimetric biosensor in flow injection analysis.  

PubMed

A highly selective, interference free biosensor for the measurement of fructose in real syrup samples was developed. The assay is based on the phosphorylation of D(-)fructose to fructose-6-phosphate by hexokinase and subsequent conversion of fructose-6-phosphate to fructose-1,6-biphosphate by fructose-6-phosphate-kinase. The heat liberated in the second reaction is monitored using an enzyme thermistor. The major advantages of this biosensor are rapid and selective measurement of fructose without the need to eliminate glucose and inexpensive FIA-based, mediator-free calorimetric measurement suitable for regular fructose analysis. This method was optimised for parameters, such as pH, ionic strength, interference, operational stability and shelf life. Good and reproducible linearity (0.5-6.0 mM) with a detection limit of 0.12 mM was obtained. Fructose determination in commercial syrup samples and spiked samples confirmed the reliability of this set-up and technique. The biosensor gave reproducible results with good overall stability for continuous measurements over a period of three months besides a useful shelf life of six months. The method could be used for routine fructose monitoring in food samples. PMID:20457296

Bhand, Sunil G; Soundararajan, Srimathi; Surugiu-Wärnmark, Ioana; Milea, Jaqueline Simona; Dey, Estera Szwajcer; Yakovleva, Maria; Danielsson, Bengt

2010-05-23

35

Application of a downstream calorimetric probe to reactive plasma  

SciTech Connect

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

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

2005-12-05

36

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.

37

Thermodynamic properties of anhydrous smectite MX-80, illite IMt-2 and mixed-layer illite smectite ISCz-1 as determined by calorimetric methods. Part I: Heat capacities, heat contents and entropies  

NASA Astrophysics Data System (ADS)

The heat capacities of the anhydrous international reference clay minerals, smectite MX-80, illite IMt-2 and mixed-layer illite-smectite ISCz-1, were measured by low temperature adiabatic calorimetry and differential scanning calorimetry, from 6 to 520 K (at 1 bar). The samples were chemically purified and Na-saturated. Dehydrated clay fractions <2 ?m were studied. The structural formulae of the corresponding clay minerals, obtained after subtracting the remaining impurities, are K0.026NaCa(SiAl) ( AlFe3+0.184MgFe2+0.038Ti) O(OH)2 for smectite MX-80, K0.762Na(SiAl) ( AlFe3+0.292MgFe2+0.084)O(OH)2 for illite IMt-2 and K0.530Na(SiAl)( AlFe3+0.051MgFe2+0.017Ti) O(OH)2for mixed-layer ISCz-1. From the heat capacity values, we determined the molar entropies, standard entropies of formation and heat contents of these minerals. The following values were obtained at 298.15 K and 1 bar: Cp0 (J mol -1 K -1) S0 (J mol -1 K -1) Smectite MX-80 326.13 ± 0.10 280.56 ± 0.16 Illite IMt-2 328.21 ± 0.10 295.05 ± 0.17 Mixed-layer ISCz-1 320.79 ± 0.10 281.62 ± 0.15

Gailhanou, H.; van Miltenburg, J. C.; Rogez, J.; Olives, J.; Amouric, M.; Gaucher, E. C.; Blanc, P.

2007-11-01

38

Metal carbon bond energies for adsorbed hydrocarbons from calorimetric data  

Microsoft Academic Search

Single crystal adsorption calorimetry (SCAC) is a powerful new method for measuring adsorption and reaction energies. Particularly for hydrocarbons, where little or no information is available from either experiment or theory on well-defined surfaces, this method can provide crucially needed information. Assignment of the measured calorimetric heats to the appropriate surface reaction yields directly reaction heats and heats of formation

Heike Gross; Charles T. Campbell; David A. King

2004-01-01

39

Accurate calorimetric power loss measurement for efficient power converters  

Microsoft Academic Search

The calorimetric power loss measurement is introduced for securing both higher accuracy measurement and faster measurement time. To reduce measurement accuracy error, copper leakage loss of wires is taken into consideration. To save measurement time, balancing relation between flow rate and temperature rise is also taken into consideration. Flow rate and temperature rise are largely dependent on sensor resolutions. To

Ryo Kamei; Tae-Woong Kim; Atsuo Kawamura

2011-01-01

40

Sensitivity of calorimetric indicators of soil microbial activity  

Microsoft Academic Search

Calorimetry was applied to develop a comparative study between the basal respiration and the degradation of an external carbon source in several soil samples. The main goals were to search for the connection between these reactions in soils and to test the sensitivity of calorimetric indices for the microbial activity. The soil samples were from the Brazilian Amazon and from

N. Barros; M. Gallego; S. Feijóo

2007-01-01

41

Calorimetric study of melted DNA glass Jessica Valle-Orero  

E-print Network

us to derive quantitative information on the relaxations of the DNA films, in particular to evaluateCalorimetric study of melted DNA glass Jessica Valle-Orero , Jean-Luc Garden , Jacques Richard differential scanning calorimetry (DSC) of the glassy behaviour of films made from DNA fibers. We show

Boyer, Edmond

42

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.

2014-09-01

43

Calorimetric and computational study of the thermochemistry of phenoxyphenols.  

PubMed

Thermodynamic properties of 3- and 4-phenoxyphenol have been determined by using a combination of calorimetric and effusion techniques as well as by high-level ab initio molecular orbital calculations. The standard (p° = 0.1 MPa) molar enthalpies of formation in the condensed and gas states, ?(f)H(m)°(cr or l) and ?(f)H(m)°(g), at T = 298.15 K, of 3- and 4-phenoxyphenol were derived from their energies of combustion in oxygen, measured by a static bomb calorimeter, and from the enthalpies of vaporization or sublimation derived respectively by Calvet microcalorimetry for the 3-phenoxyphenol and by Knudsen effusion technique for the 4-phenoxyphenol. The theoretically estimated gas-phase enthalpies of formation were calculated from high-level ab initio molecular orbital calculations at the G3(MP2)//B3LYP level of theory. Furthermore, this composite approach was also used to obtain information about the gas-phase acidities, gas-phase basicities, proton and electron affinities, adiabatic ionization enthalpies, and, finally, O?H bond dissociation enthalpies. The good agreement between the G3MP2B3-derived values and the experimental gas-phase enthalpies of formation for the 3- and 4-phenoxyphenol gives confidence to the estimate concerning the 2-phenoxyphenol isomer, which was not experimentally studied, and to the estimates concerning the radical and the anion. Additionally, the experimental values of gas-phase enthalpies of formation were also compared with estimates based on the empirical scheme developed by Cox. PMID:21486007

Ribeiro da Silva, Manuel A V; Lobo Ferreira, Ana I M C; Cimas, Álvaro

2011-05-20

44

Calorimetric aspects of adsorption of pesticides 2,4- d , diuron and atrazine on a magadiite surface  

Microsoft Academic Search

H-magadiite was applied to remove the pesticides 2,4-d, diuron, and atrazine from water. The H-magadiite containing herbicides adsorbed were investigated by FTIR, DRX, N2 adsorption and desorption isotherms, and surface area. Calorimetric studies were carried out to determine the heat of interaction\\u000a between pesticides and magadiite. It was possible to ride the cycle of interaction of magadiite–pesticide for a better

Alécio R. Nunes; Aline O. Moura; Alexandre G. S. Prado

45

Calorimetric, thermomechanical, and rheological characterizations of bulk glass-forming Pd40Ni40P20  

NASA Astrophysics Data System (ADS)

Calorimetric, thermomechanical, and rheological properties of undercooled liquid Pd40Ni40P20 were determined within a wide temperature range above the glass transition. The concept of the limiting fictive temperature was applied to the entire set of measurements to compare the different properties adequately. It was found that an equilibrium state of a sample that is defined by its calorimetric glass temperature corresponds to a similar equilibrium state for the specific volume and for the shear viscosity as well. The Kauzmann temperature as one of the most important material characteristics concerning the glass transition could be determined with high accuracy leading to the evaluation of the free volume persistent in the samples. Viscosity values of the liquid extending over a range of about nine orders in magnitude could be described best by the free volume theory evaluated by Cohen and Grest, provided that experimentally obtained parameters were used for the calculations. The comparison between nonequilibrium measurements at isochronous heating and model calculations in the framework of bimolecular reaction kinetics shows that good agreement can be achieved using thermodynamic parameters that have been obtained from equilibrium measurements. However, systematic deviations indicate also the limitations of the model that are related to the intrinsic dynamic heterogeneity of the vitreous state.

Wilde, G.; Görler, G. P.; Willnecker, R.; Fecht, H. J.

2000-02-01

46

Calorimetric Investigation of Hydrogen Bonding of Formamide and Its Methyl Derivatives in Organic Solvents and Water  

NASA Astrophysics Data System (ADS)

Formamide and its derivatives have a large number of practical applications; also they are structural fragments of many biomolecules. Hydrogen bonds strongly affect their physicochemical properties. In the present work a calorimetric study of formamide and its methyl derivatives was carried out. Enthalpies of solution at infinite dilution of formamide, N-methylformamide, and N, N-dimethylformamide in organic solvents at 298.15 K were measured. The relationships between the obtained enthalpies of solvation and the structure of the studied compounds were observed. Hydrogen-bond enthalpies of amides with chlorinated alkanes, ethers, ketones, esters, nitriles, amines, alcohols, and water were determined. The strength of hydrogen bonds of formamide, N-methylformamide, and N, N-dimethylformamide with proton donor solvents is practically equal. Enthalpies of hydrogen bonds of formamide with the proton acceptor solvents are two times larger in magnitude than the enthalpies of N-methylformamide. The process of hydrogen bonding of amides in aliphatic alcohols and water is complicated. The obtained enthalpies of hydrogen bonding in aliphatic alcohols vary considerably from the amide structure due to the competition between solute-solvent and solvent-solvent hydrogen bonds. Fourier transform infrared spectroscopic measurements were carried out to explain the calorimetric data. Hydration enthalpies of methyl derivatives of formamides contain a contribution of the hydrophobic effect. New thermochemical data on the hydrogen bonding of formamides may be useful for predicting the properties of biomacromolecules.

Varfolomeev, Mikhail A.; Rakipov, Ilnaz T.; Solomonov, Boris N.

2013-04-01

47

Micro-calorimetric sensor for trace explosive particle detection  

NASA Astrophysics Data System (ADS)

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

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

2010-04-01

48

Calorimetric studies of curium complexation. 2. Amino carboxylates  

Microsoft Academic Search

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

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

1987-01-01

49

Calorimetric seasonal characterization of culture and pasture soils  

Microsoft Academic Search

Isothermal and Differential Scanning Calorimetry is applied to analyze the evolution of soil using its microorganisms and\\u000a organic matter as bioindicators of soil quality. This study was carried out with two similar soils under different agricultural\\u000a activities: culture and pasture. Sampling and measurements were performed through 1 year in order to check the sensitivity\\u000a of common calorimetric indicators of microbial activity

J. Salgado; M. Villanueva; O. Núñez-Fernández; J. Proupín-Castiñeiras; N. Barros; J. A. Rodríguez-Añón

2009-01-01

50

Calorimetric low temperature detectors for low-energetic heavy ions and their application in accelerator mass spectrometry  

NASA Astrophysics Data System (ADS)

The energy-sensitive detection of heavy ions with calorimetric low temperature detectors was investigated in the energy range of E =0.1-1 MeV/amu, commonly used for accelerator mass spectrometry (AMS). The detectors used consist of sapphire absorbers and superconducting aluminum transition edge thermometers operated at T ˜1.5 K. They were irradiated with various ion beams (C13,A197u,U238) provided by the VERA tandem accelerator in Vienna, Austria. The relative energy resolution obtained was ?E /E=(5-9)×10-3, even for the heaviest ions such as U238. In addition, no evidence for a pulse height defect was observed. This performance allowed for the first time to apply a calorimetric low temperature detector in an AMS experiment. The aim was to precisely determine the isotope ratio of U236/U238 for several samples of natural uranium, U236 being known as a sensitive monitor for neutron fluxes. Replacing a conventionally used detection system at VERA by the calorimetric detector enabled to substantially reduce background from neighboring isotopes and to increase the detection efficiency. Due to the high sensitivity achieved, a value of U236/U238=6.1×10-12 could be obtained, representing the smallest U236/U238 ratio measured at the time. In addition, we contributed to establishing an improved material standard of U236/U238, which can be used as a reference for future AMS measurements.

Kraft-Bermuth, S.; Andrianov, V. A.; Bleile, A.; Echler, A.; Egelhof, P.; Kiseleva, A.; Kiselev, O.; Meier, H. J.; Meier, J. P.; Shrivastava, A.; Weber, M.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.; Vockenhuber, C.

2009-10-01

51

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

...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...made to any State under title I, IV-A, X, XIV or XVI of the Social...

2014-10-01

52

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

Code of Federal Regulations, 2011 CFR

...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...made to any State under title I, IV-A, X, XIV or XVI of the Social...

2011-10-01

53

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

Code of Federal Regulations, 2013 CFR

...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...made to any State under title I, IV-A, X, XIV or XVI of the Social...

2013-10-01

54

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

Code of Federal Regulations, 2010 CFR

...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...made to any State under title I, IV-A, X, XIV or XVI of the Social...

2010-10-01

55

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

Code of Federal Regulations, 2012 CFR

...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...assistance programs under titles I, IV-A, X, XIV and XVI of the Social Security Act...made to any State under title I, IV-A, X, XIV or XVI of the Social...

2012-10-01

56

Laser power precise measurement using calorimetric method  

Microsoft Academic Search

A new double calorimeter designed in order to establish the continuous-wave laser power mesurement standard is described. The double calorimeter consists of a standard thermopile unit with fast response and an electronic cooling calorimeter whose thermal load is borne by the thermopile unit. The characteristics of the two units are studied in detail. Various errors related to determining the effective

T. Honda

1983-01-01

57

Calorimetric investigations of the different castes of honey bees, Apis mellifera carnica  

Microsoft Academic Search

Honey bees of different age and castes were investigated calorimetrically at 20, 25 and 30 °C. Experiments were completed by endoscopic observation of the insects in the visible and the near infrared range and by acoustical monitoring and subsequent frequency analysis of various locomotor activities. Direct calorimetric results of this paper are compared with data of indirect calorimetry from the

L. Fahrenholz; I. Lamprecht; B. Schricker

1992-01-01

58

[Calorimetric evaluation of directly compressed tablets].  

PubMed

The paper studies the effect of the type of the disintegrating substance and the lubricant on the destruction heat of tablet materials and tablets. Destruction heat was determined by means of isoperibolic calorimetry. Tablet materials and tablets contained Avicel PH 101 as the dry binder, 10% of Primojel, Ac-Di-Sol, or Polyplasdone XL as disintegrating substances, and 5% of magnesium strearate or sodium laurylsulfate as the lubricants. The sum of destruction heats of the individual auxiliary substances equalled the found values in tablet materials and tablets. In tablets, in contrast to tablet materials, values of destruction heat higher by 57.9% were found. In the disintegrating substances and lubricants tested, the found values of destruction heats were dependent on the values of destruction heats of the individual auxiliary substances. In the disintegrating substances, a linear dependence of the total destruction heat (CDT) on the destruction heat of the disintegrating substances (DTR) was found, given by the relationship CDT = 0.797.DTR + 17.666 with the correlation coefficient r = 0.986. PMID:11242832

Rehula, M; Lavická, J; Musilová, M

2001-01-01

59

Induction of type XVI collagen expression facilitates proliferation of oral cancer cells.  

PubMed

Type XVI collagen belongs to the family of fibril-associated collagens with interrupted triple helices (FACIT). Recently, high affinity to integrin alpha1beta1 has been shown allowing cells expressing those integrins to attach and spread on recombinant type XVI collagen. Here, we show that type XVI collagen is overexpressed in dysplastic areas of mucosal epithelium from oral squamous cell carcinoma (OSCC) patients. Induction of its expression in OSCC cell lines (COLXVI cells) leads to an increased expression of Kindlin-1. Moreover, we demonstrate a significantly increased Kindlin-1/beta1-integrin interaction. Additionally, we detected a higher number of activated beta1-integrins in COLXVI cells and found a neo-expression of alpha1 integrin subunit on these cells. FACS analysis revealed a significantly higher amount of COLXVI cells in S-phase and G2/M-phase 6h after synchronisation leading to a markedly higher proliferation activity. Blocking beta1-integrins with a specific antibody resulted in reduced proliferation of COLXVI cells. In summary, we demonstrate that overexpression of type XVI collagen in aberrant oral keratinocytes leads to Kindlin-1 induction, increased Kindlin-1/beta1-integrin interaction, integrin activation and subsequently to a proliferative cellular phenotype. PMID:21251976

Ratzinger, Sabine; Grässel, Susanne; Dowejko, Albert; Reichert, Torsten E; Bauer, Richard J

2011-03-01

60

American Press Coverage of the Execution of Louis XVI: A Lesson Strategy for Gauging Opinion.  

ERIC Educational Resources Information Center

In this unit of study high school students read and discuss U.S. newspaper articles reporting the trial and execution of the French king Louis XVI. Students look for key words and phrases that might indicate a subtle favorable or unfavorable opinion. (RM)

Lankiewicz, Donald

1985-01-01

61

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

62

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

Federal Register 2010, 2011, 2012, 2013

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

2013-04-15

63

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

Federal Register 2010, 2011, 2012, 2013

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

2013-02-05

64

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

Federal Register 2010, 2011, 2012, 2013

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

2013-02-12

65

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

Federal Register 2010, 2011, 2012, 2013

...Docket No. SSA-2012-0006] Social Security Ruling, SSR 13-2p; Titles II and XVI: Evaluating Cases Involving Drug Addiction and Alcoholism (DAA); Correction AGENCY: Social Security Administration. ACTION: Notice of Social Security...

2013-03-22

66

Fast electron thermometry towards ultra-sensitive calorimetric detection  

E-print Network

We demonstrate radiofrequency thermometry on a micrometer-sized metallic island below 100 mK. Our device is based on a normal metal-insulator-superconductor tunnel junction coupled to a resonator with transmission readout. In the first generation of the device, we achieve 90 {\\mu}K/Hz^1/2 noise-equivalent temperature with 10 MHz bandwidth. We measure the thermal relaxation time of the electron gas in the island, which we find to be of the order of 100 {\\mu}s. Such a calorimetric detector, upon optimization, can be seamlessly integrated into superconducting circuits, with immediate applications in quantum-thermodynamics experiments down to single quanta of energy.

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

2014-11-04

67

Huwentoxin-XVI, an analgesic, highly reversible mammalian N-type calcium channel antagonist from Chinese tarantula Ornithoctonus huwena.  

PubMed

N-type calcium channels play important roles in the control of neurotransmission release and transmission of pain signals to the central nervous system. Their selective inhibitors are believed to be potential drugs for treating chronic pain. In this study, a novel neurotoxin named Huwentoxin-XVI (HWTX-XVI) specific for N-type calcium channels was purified and characterized from the venom of Chinese tarantula Ornithoctonus huwena. HWTX-XVI is composed of 39 amino acid residues including six cysteines that constitute three disulfide bridges. HWTX-XVI could almost completely block the twitch response of rat vas deferens to low-frequency electrical stimulation. Electrophysiological assay indicated that HWTX-XVI specifically inhibited N-type calcium channels in rat dorsal root ganglion cells (IC50 ?60 nM). The inhibitory effect of HWTX-XVI on N-type calcium channel currents was dose-dependent and similar to that of CTx-GVIA and CTx-MVIIA. However, the three peptides exhibited markedly different degrees of reversibility after block. The toxin had no effect on voltage-gated T-type calcium channels, potassium channels or sodium channels. Intraperitoneal injection of the toxin HWTX-XVI to rats elicited significant analgesic responses to formalin-induced inflammation pain. Toxin treatment also changed withdrawal latency in hot plate tests. Intriguingly, we found that intramuscular injection of the toxin reduced mechanical allodynia induced by incisional injury in Von Frey test. Thus, our findings suggest that the analgesic potency of HWTX-XVI and its greater reversibility could contribute to the design of a novel potential analgesic agent with high potency and low side effects. PMID:24467846

Deng, Meichun; Luo, Xuan; Xiao, Yucheng; Sun, Zhenghua; Jiang, Liping; Liu, Zhonghua; Zeng, Xiongzhi; Chen, Hanchun; Tang, Jianhua; Zeng, Weimin; Songping Liang

2014-04-01

68

Photoionization cross sections for Fe XVI and Fe XVII recombination rate coefficients  

NASA Astrophysics Data System (ADS)

The Breit-Pauli R-matrix codes are utilized in a detailed study of the photoionization of the ground state of Fe XVI (2s(22p^63s) (2S_{1/2}) ). High resolution total and partial cross sections are obtained using 37 Jpi configuration interaction type wavefunctions to represent the residual ion, Fe XVII, after 3s, 2p and 2s photoionization. For the total cross section, the work of Verner et al. and previous Opacity Project calculations are in fair agreement with the present results, while relativistic effects are seen to have a noticeable but not an overly significant effect on the background cross section. The derived partial cross sections are used in a calculation of rates for the recombination of states of Fe XVII to the ground state of Fe XVI.

Donnelly, D.; Bell, K. L.; Darlington, W. G. V.; Reid, R. H. G.; Keenan, F. P.

1999-09-01

69

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

70

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

PubMed

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

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

2014-01-01

71

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

PubMed Central

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

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

2014-01-01

72

Laser calorimetric absorptance testing of samples with varying geometry  

NASA Astrophysics Data System (ADS)

Laser calorimetry is based on the measurement and evaluation of the temperature increase caused by absorption in the sample exposed to laser radiation. A temperature distribution develops in the irradiated sample as a result of dependence on the thermal diffusivity of the sample. Therefore, finding a correlation between the temperature increase and absorption becomes a complex task. This challenge was met by keeping the sample geometry at a standard size and simulating the thermal distribution for a number of optical materials. Using this method, Laser Zentrum Hannover e.V. (LZH) developed a calorimetric test setup that offers fully calibrated absorptance values for sample diameters of 25 mm (or 1 in.) with a total error of below 13% and a relative measurement error of below 5%. However, this technique is limited to the above-mentioned sample geometry. This work presents an approach to adjust the measurement configuration to numerous sample sizes for standard circular laser components. Finite element analysis and experimental verification are presented for exemplary values of the samples' diameters. Based on the different sample mount concept, this procedure allows utilizing flexibility in test wavelength and angle of incidence, combined with the sensitivity level sufficient for current optical materials.

Balasa, Istvan; Jensen, Lars O.; Ristau, Detlev

2014-12-01

73

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

74

Adsorption of methylene blue on raw and MTZ/imogolite hybrid surfaces: effect of concentration and calorimetric investigation.  

PubMed

The synthetic imogolite sample was used for organofunctionalization process with 2-mercaptothiazoline (MTZ). The compound 2-mercaptothiazoline was anchored onto imogolite surface by heterogeneous route. Due to the increment of basic centers attached to the pendant chains the dye adsorption capability of the final chelating material, was found to be higher than is precursor. The ability of these materials to remove methylene blue 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 40.32×10(-2) and 65.13×10(-2) mmol g(-1) for IMO and IMO(MTZ), respectively. The energetic effects caused by dye cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such methylene blue-nitrogen and sulfur interactions. PMID:20674169

Guerra, Denis L; Batista, Adriano C; Viana, Rúbia R; Airoldi, Claudio

2010-11-15

75

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

76

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

PubMed

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

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

2014-02-14

77

Oxindolealanine-62 lysozyme: equilibrium, calorimetric, and kinetic studies of the reaction with N-acetylglucosamine oligosaccharides.  

PubMed

Oxindolealanine-62 lysozyme, formed by reaction with N-bromosuccinimide and purified by using affinity chromatography, was examined in its binding of homologous oligosaccharides of N-acetylglucosamine and in its catalysis of hydrolysis and of transglycosylation of the hexasaccharide of N-acetylglucosamine. Equilibrium binding constants were determined by changes in absorbance or fluorescence associated with ligand binding. Enthalpies of binding were measured calorimetrically. The pattern of variation of delta Go and delta Ho of binding with ligand chain length and pH was different for oxindolealanine-62 lysozyme compared with native lysozyme. These results indicate that the interactions of the ABC region of the active site with substrates are substantially altered by Trp-62 oxidation, more than expected for loss only of the Trp-62 interactions. The partitioning of the glycosyl enzyme intermediate between reaction with a saccharide acceptor (transglycosylation) and reaction with water is unaffected by oxidation of Trp-62. Similarly, the pattern of cleavage of the hexasaccharide, predominantly to tetra- and disaccharide, is unaffected by oxidation of Trp-62. The 2000-fold slower rate of catalytic reaction (relative to free enzyme and substrate) apparently reflects a sterically hindered fit of the substrate into the active site of the modified enzyme and not a special catalytic importance of Trp-62. The geometry of the transition state for oligosaccharide hydrolysis is inferred to be the same for native and oxidized enzymes. PMID:7407080

Shrake, A; Rupley, J A

1980-08-19

78

Energy levels, radiative rates and electron impact excitation rates for transitions in Be-like Cl XIV, K XVI and Ge XXIX  

NASA Astrophysics Data System (ADS)

Results for energy levels, radiative rates and electron impact excitation (effective) collision strengths for transitions in Be-like Cl XIV, K XVI and Ge XXIX are reported. For the calculations of energy levels and radiative rates the general-purpose relativistic atomic structure package is adopted, while for determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code is used. Oscillator strengths, radiative rates and line strengths are listed for all E1, E2, M1 and M2 transitions among the lowest 98 levels of the n?slant 4 configurations. Furthermore, lifetimes are provided for all levels and comparisons made with available theoretical and experimental results. Resonances in the collision strengths are resolved in a fine energy mesh and averaged over a Maxwellian velocity distribution to obtain the effective collision strengths. Results obtained are listed over a wide temperature range up to 107.8 K, depending on the ion.

Aggarwal, Kanti M.; Keenan, Francis P.

2014-12-01

79

Genetic analysis of the presumptive blood from Louis XVI, King of France.  

PubMed

A text on a pyrographically decorated gourd dated to 1793 explains that it contains a handkerchief dipped with the blood of Louis XVI, king of France, after his execution. Biochemical analyses confirmed that the material contained within the gourd was blood. The mitochondrial DNA (mtDNA) hypervariable region 1 (HVR1) and 2 (HVR2), the Y-chromosome STR profile, some autosomal STR markers and a SNP in HERC2 gene associated to blue eyes, were retrieved, and some results independently replicated in two different laboratories. The uncommon mtDNA sequence retrieved can be attributed to a N1b haplotype, while the novel Y-chromosome haplotype belongs to haplogroup G2a. The HERC2 gene showed that the subject analyzed was a heterozygote, which is compatible with a blue-eyed person, as king Louis XVI was. To confirm the identity of the subject, an analysis of the dried heart of his son, Louis XVII, could be undertaken. PMID:20940110

Lalueza-Fox, Carles; Gigli, Elena; Bini, Carla; Calafell, Francesc; Luiselli, Donata; Pelotti, Susi; Pettener, Davide

2011-11-01

80

Astronomical Data Analysis Software and Systems XVI D1.1 ASP Conference Series, Vol. XXX, 2006  

E-print Network

Astronomical Data Analysis Software and Systems XVI D1.1 ASP Conference Series, Vol. XXX, 2006 R, Durham University, South Road, Durham DH1 3LE, UK Malcolm J. Currie CCLRC Rutherford Appleton Laboratory Physics Laboratory, Bristol University, Tyndall Avenue, Bristol, BS8 1TL, UK Abstract. The GAIA 1

Taylor, Mark

81

David Rudd, ed. The Routledge Companion to Children's Literature, Routledge, 2009. xvi + 320 pp. $32.95 (hardcover). ISBN 9780415472715.  

E-print Network

, literature written by children, writings by parents for their own children, oral tradition, poetry, and playsDavid Rudd, ed. The Routledge Companion to Children's Literature, Routledge, 2009. xvi + 320 pp. $32.95 (hardcover). ISBN 9780415472715. Reviewed by Ernest Davis Children's literature has at least

Davis, Ernest

82

Paper to XVI IMEKO World Congress 2000, 25-28 Sept. 2000, Vienna REFRACTION INFLUENCE ANALYSIS AND  

E-print Network

Paper to XVI IMEKO World Congress 2000, 25-28 Sept. 2000, Vienna REFRACTION INFLUENCE ANALYSIS AND INVESTIGATIONS ON AUTOMATED ELIMINATION OF REFRACTION EFFECTS ON GEODETIC MEASUREMENTS B. Böckem1 , P. Flach1 , A of Geodesy and Photogrammetry 2 Institute of Geography Abstract: Refraction effects are generally caused

83

The Hydrogen Bonding of Cytosinewith Guanine:Calorimetric and`H-NMR Analysis  

E-print Network

The Hydrogen Bonding of Cytosinewith Guanine:Calorimetric and`H-NMR Analysis of the Molecular of hydrogen-bondformation between guanine (G) and cytusine (C) in o-dichloro- benzene and in chloroformat 25°C forming hydrogen bonds. Consequently, hydrogen-bond formation in our system is primarily between the bases

Williams, Loren

84

Metal–carbon bond energies for adsorbed hydrocarbons from calorimetric data  

Microsoft Academic Search

Single crystal adsorption calorimetry (SCAC) is a powerful new method for measuring adsorption and reaction energies. Particularly for hydrocarbons, where little or no information is available from either experiment or theory on well-defined surfaces, this method can provide crucially needed information. Assignment of the measured calorimetric heats to the appropriate surface reaction yields directly reaction heats and heats of formation

Heike Gross; Charles T. Campbell; David A. King

2004-01-01

85

First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho  

E-print Network

The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we discuss the implications of this result for the Electron Capture $^{163}$Ho experiment, ECHo, aiming to reach sub-eV sensitivity on the electron neutrino mass by a high precision and high statistics calorimetric measurement of the $^{163}$Ho spectrum.

P. C. -O. Ranitzsch; C. Hassel; M. Wegner; S. Kempf; A. Fleischmann; C. Enss; L. Gastaldo; A. Herlert; K. Johnston

2014-08-30

86

Calorimetric measurements of heat of sorption in polymer films: A molecular modeling and experimental study  

Microsoft Academic Search

We report a combined molecular modeling and experimental effort to predict and measure the heat of sorption of target molecules in a polymer film. The primary focus of this work is to demonstrate and validate the applicability of molecular modeling techniques as a predictive tool to evaluate polymeric sensing films for micro-calorimetric chemical sensor applications. In the current investigation, molecular

A. V. Shevade; M. A. Ryan; M. L. Homer; A. K. Kisor; K. S. Manatt; B. Lin; J.-P. Fleurial; A. M. Manfreda; S.-P. S. Yen

2005-01-01

87

Calorimetric detection of the conical THz radiation from femtosecond laser filaments in air  

E-print Network

1 Calorimetric detection of the conical THz radiation from femtosecond laser filaments in air terahertz (THz) emission from a femtosecond laser filament in air is measured with a bolometric detector and a set of filters, confirming that the main part of the emission lies between 0.5 and 3 THz

Paris-Sud XI, Université de

88

Calorimetric investigations on thermoregula-tion and growth of wax moth larvae (Galleria  

E-print Network

Calorimetric investigations on thermoregula- tion and growth of wax moth larvae (Galleria mellonella) The larvae of the wax moth Galleria mellonella are living in honeybee colonies where they feed on wax, honey, pollen and other organic matter. Mass-invasions of larvae can occur in weak bee colonies

Paris-Sud XI, Université de

89

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

PubMed

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

Sultan, Nabil Ali Mohammed; Swamy, Musti J

2005-05-01

90

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

91

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

92

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

93

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

94

Calorimetric studies of hydrophobic interactions of alkanols in concentrated aqueous solutions of glucose  

Microsoft Academic Search

Calorimetric measurements were carried out at 298K on concentrated aqueous solutions of glucose, ranging from 0 to 5molkg?1, containing alkan-1-ols, alkane-1,2-diols and alkane-?,?-diols from C2 to C7. The purpose of this study is to obtain more information about the influence of glucose on hydrophobic hydration and interactions. The pair-wise interaction coefficients of the virial expansion of the excess enthalpies were

Giuseppina Castronuovo; Vittorio Elia; Marcella Niccoli; Filomena Velleca

2002-01-01

95

Calorimetric method of ac loss measurement in a rotating magnetic field  

Microsoft Academic Search

A method is described for calorimetric ac-loss measurements of high-Tc superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup

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

2010-01-01

96

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

PubMed Central

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) The binding affinity of neomycin decreases with increased pH, although there is an increase in observed binding enthalpy. (3) ITC studies conducted in two buffers (sodium cacodylate and MOPS) yield the number of protonated drug amino groups (?n) as 0.29 and 0.40 for neomycin and paromomycin interaction with 5?-dA12-x-dT12-x-dT12-3?, respectively. (4) The specific heat capacity change (?Cp) determined by ITC studies is negative, with more negative values at lower salt concentrations. From 100 mM to 250 mM KCl, the ?Cp ranges from ?402 to ?60 cal/(mol K) for neomycin. At pH 5.5, a more positive ?Cp is observed, with a value of ?98 cal/(mol K) at 100 mM KCl. ?Cp is not significantly affected by ionic strength. (5) Salt dependence studies reveal that there are at least three amino groups of neomycin participating in the electrostatic interactions with the triplex. (6) FID studies using thiazole orange were used to derive the AC50 (aminoglycoside concentration needed to displace 50% of the dye from the triplex) values. Neomycin shows a seven fold higher affinity than paromomycin and eleven fold higher affinity than ribostamycin at pH 6.8. (7) Modeling studies, consistent with UV and ITC results, show the importance of an additional positive charge in triplex recognition by neomycin. The modeling and thermodynamic studies indicate that neomycin binding to the DNA triplex depends upon significant contributions from charge as well as shape complementarity of the drug to the DNA triplex Watson–Hoogsteen groove. PMID:20167243

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

2013-01-01

97

Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Cl XVI, K XVIII, Ca XIX and Sc XX  

NASA Astrophysics Data System (ADS)

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Cl XVI, K XVIII, Ca XIX and Sc XX. The GRASP (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. To determine the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (DARC) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 107.4 K. Comparisons are made with similar data obtained from the flexible atomic code (FAC) to highlight the importance of resonances, included in calculations with DARC, in the determination of effective collision strengths. Discrepancies between the collision strengths from DARC and FAC, particularly for forbidden transitions, are also discussed. Additionally, theoretical lifetimes are listed for all the 49 levels of the above four ions.

Aggarwal, Kanti M.; Keenan, Francis P.

2012-02-01

98

The calorimetric-respirometric ratio is an on-line marker of enthalpy efficiency of yeast cells growing on a non-fermentable carbon source.  

PubMed

Although on-line calorimetry has been widely used to detect transitions in global metabolic activity during the growth of microorganisms, the relationships between oxygen consumption flux and heat production are poorly documented. In this work, we developed a respirometric and calorimetric approach to determine the enthalpy efficiency of respiration-linked energy transformation of isolated yeast mitochondria and yeast cells under growing and resting conditions. On isolated mitochondria, the analysis of different phosphorylating and non-phosphorylating steady states clearly showed that the simultaneous measurements of heat production and oxygen consumption rates can lead to the determination of both the enthalpy efficiency and the ATP/O yield of oxidative phosphorylation. However, these determinations were made possible only when the net enthalpy change associated with the phosphorylating system was different from zero. On whole yeast cells, it is shown that the simultaneous steady state measurements of the heat production and oxygen consumption rates allow the enthalpy growth efficiency (i.e. the amount of energy conserved as biomass compared to the energy utilised for complete catabolism plus anabolism) to be assessed. This method is based on the comparison between the calorimetric-respirometric ratio (CR ratio) determined under growth versus resting conditions during a purely aerobic metabolism. Therefore, in contrast to the enthalpy balance approach, this method does not rely on the exhaustive and tedious determinations of the metabolites and elemental composition of biomass. Thus, experiments can be performed in the presence of non-limiting amounts of carbon substrate, an approach which has been successfully applied to slow growing cells such as yeast cells expressing wild-type or a mutant rat uncoupling protein-1. PMID:11115644

Dejean, L; Beauvoit, B; Bunoust, O; Fleury, C; Guérin, B; Rigoulet, M

2001-01-19

99

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  

SciTech Connect

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., E-mail: frederic.plantier@univ-pau.fr; Missima, D.; Torré, J.-P. [Univ Pau and Pays Adour, CNRS, TOTAL - UMR 5150 – LFC-R - Laboratoire des Fluides Complexes et leurs Réservoirs, BP 1155 – PAU, F-64013 (France)] [Univ Pau and Pays Adour, CNRS, TOTAL - UMR 5150 – LFC-R - Laboratoire des Fluides Complexes et leurs Réservoirs, BP 1155 – PAU, F-64013 (France); Marlin, L. [Univ Pau and Pays Adour, IPRA FR2952 - Fédération de Recherche- Atelier de Physique Générale, BP 1155 – PAU, F-64013 (France)] [Univ Pau and Pays Adour, IPRA FR2952 - Fédération de Recherche- Atelier de Physique Générale, BP 1155 – PAU, F-64013 (France)

2013-12-15

100

Simultaneous measurements of high-temperature total hemispherical emissivity and thermal conductivity using a steady-state calorimetric technique  

NASA Astrophysics Data System (ADS)

A method was developed to simultaneously measure the total hemispherical emissivity and the thermal conductivity of samples at high temperatures. The inverse problem to determine the emissivity and thermal conductivity from steady-state high-temperature calorimetric experiments was established based on models for these two quantities. The accuracy of the inverse solution was numerically analyzed for various noise levels for samples with various thermophysical properties. The simulation results illustrate that the calculation accuracies for the emissivity and thermal conductivity strongly depend on the proportions of the radiation and conduction heat fluxes in the strip sample arising from the temperature distributions in the sample. Steady-state high-temperature experiments with nickel samples were used to experimentally verify the method. The inverse solution results for the emissivity and thermal conductivity calculated from the measured data agree well with reported data in the literature. This research provides a useful reference for measuring the total hemispherical emissivity and thermal conductivity of conductive samples at high temperatures.

Fu, Tairan; Tan, Peng; Duan, Minghao

2015-01-01

101

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

102

Radioactivity measurements of 153Gd pellet sources by calorimetric methods  

Microsoft Academic Search

The thermal power generation per 37 MBq (1 mCi) of 153Gd is 0.839 muW. The activity of a sealed 153Gd source can be determined by absorbing all radiations within a calorimeter to be converted into the thermal power. Sources are sintered pellets (3 mm diameter, 2 mm thickness) of Gd2O3.Al2O3 which are encapsulated in titanium capsules of 7 mm diameter

Tsuguo Genka; Tsuyoshi Imahashi

1992-01-01

103

[Sanitary control of communicable diseases in Hispanic America in the XVI, XVII, and XVIII centuries].  

PubMed

In each time and each place, man has avoided diseases, has tried to limit diffusion of diseases. The purpose of this article was to present in a general manure the measures taken in Hispano America during colonial times to control communicable diseases. The main problems of health during the XVI, XVII, and XVIII centuries, in Hispano American region were communicable diseases. Practices to avoid them derived from observation, control measures referred to stay away from the contagious places, and to isolate sick persons by means of quarantine, and implied some epidemiologic surveillance. The supply of safe drinking water, sewage disposal systems and sanitary control of food were not habitual practices; garbage, residuals, and waste collection were not opportune, This favored the existence of vectors-insects and animals. Domestic waste did not go away in a timely fashion, it allowed to accumulate excreta and waste near houses. In some places, the were measures related to water supply, excreta disposal, handling of dead bodies, and environmental sanitation. It was believed that with prayers and processions, prevalent diseases could be avoided. Demographic information, data on mortality, births, and morbidity, were irregular and incompletes, some data were compiled in parishes: physicians should inform and notify the governmental medical board, which regulated medicine and public heath who the cared for an action carried out only as and exception. Compiled data had no clear medical or sanitary use. PMID:14723058

Fajardo-Ortiz, Guillermo; Ferrer-Burgos, Yolloxóchitl

2003-01-01

104

An Isothermal Titration Calorimetric Method to Determine the Kinetic Parameters of Enzyme Catalytic Reaction  

E-print Network

Chemistry of Stable and Unstable Species, Peking University, Beijing 100871, China Received June 20, 2001 of enzyme. The molar reaction heat was calculated from the titration peak area divided by substrate moles change the reaction curve, it can be used as a probe to dig out other useful information. In this paper

Luhua, Lai

105

A method for determining crystallization kinetic parameters from one nonisothermal calorimetric experiment  

E-print Network

­4 for the isothermal nucleation and growth process x 1 - exp(-Ktn ) , (1) where x is the volume fraction transformed , (2a) in which (1 - x) is the impingement factor, and nKtn-1 gives the rate law in the absence

Mitchell, Brian S.

106

Calorimetric Determination of the Enthalpies of Formation of Liquid Ni-Zr Alloys  

Microsoft Academic Search

The enthalpies of formation of liquid Ni-Zr alloys have been measured through the composition range 0 zr zr is the mole fraction of Zr. Four independent runs were made at temperatures ranging from 1740 to 1743 K and one at 1838 K.\\u000a The compositional dependence of the enthalpies of formation could be fitted quite well with polynomial representations according\\u000a to

I Arpshofen; R. Liick; B. Predel; J. F Smith

1991-01-01

107

Radioactivity measurements of 153Gd pellet sources by calorimetric methods  

NASA Astrophysics Data System (ADS)

The thermal power generation per 37 MBq (1 mCi) of 153Gd is 0.839 ?W. The activity of a sealed 153Gd source can be determined by absorbing all radiations within a calorimeter to be converted into the thermal power. Sources are sintered pellets (3 mm diameter, 2 mm thickness) of Gd2O3·Al2O3 which are encapsulated in titanium capsules of 7 mm diameter and 10 mm length. A cylindrical radiation absorber made of solid copper having a space in the center for the 153Gd source is used and the temperature rise of the absorber is measured. Uncertainties are added up to ±2.9% for a 3? confidence interval in the final result for the measurement of the activity of an approximately 1.5 GBq (40 mCi) pellet source of 153Gd in a fully nondestructive way.

Genka, Tsuguo; Imahashi, Tsuyoshi

1992-02-01

108

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

SciTech Connect

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

Lee, Dongkyu, E-mail: dongkyu@ualberta.ca; Chae, Inseok; Thundat, Thomas [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada); Kim, Seonghwan [Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Jeon, Sangmin [Department of Chemical Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of)

2014-04-07

109

Calorimetric and structural studies of tetrabutylammonium bromide ionic clathrate hydrates.  

PubMed

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

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

2013-09-12

110

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

111

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%. PMID:24818660

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

2014-01-01

112

Calorimetric method of ac loss measurement in a rotating magnetic field  

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

113

Calorimetric method of ac loss measurement in a rotating magnetic field  

SciTech Connect

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

Ghoshal, P. K. [Oxford Instruments NanoScience, Abingdon, Oxfordshire OX13 5QX (United Kingdom); Coombs, T. A.; Campbell, A. M. [Department of Engineering, Electrical Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

2010-07-15

114

Do methane measurements from a laser detector and an indirect open-circuit respiration calorimetric chamber agree sufficiently closely?  

Microsoft Academic Search

In ruminant production, there is a need for inexpensive, convenient and practical methods for quantifying the amount of enteric methane produced by cows. The current study tested the level of agreement between a recently developed proprietary laser methane detector (LMD) and the indirect open-circuit respiration calorimetric chamber. The test was based on two different methods, these are: Pearson correlation and

M. G. G. Chagunda; T. Yan

2011-01-01

115

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

ERIC Educational Resources Information Center

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

Journal of Science Education and Technology, 2014

2014-01-01

116

'Gold bug' sheds new light on old question Page 1 Vol. XVI, Issue 41 for the Amherst campus of the University of Massachusetts August 24, 2001  

E-print Network

'Gold bug' sheds new light on old question Page 1 Vol. XVI, Issue 41 for the Amherst campus of the University of Massachusetts August 24, 2001 Go `Gold bug' sheds new light on old question Lovley uses pollution cleanup technology to explain gold deposits by Paula Hartman Cohen, News Office Staff Derek Lovley

Lovley, Derek

117

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

118

Total hemispherical emittance measured at high temperatures by the calorimetric method  

SciTech Connect

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

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

1994-09-01

119

a Calorimetric Study of the Precipitation Hardening Mechanisms in AN Al-Cu-Mg-Si Alloy  

NASA Astrophysics Data System (ADS)

The precipitation phenomena and the related hardening in an Al-Cu-Mg-Si alloy were studied by calorimetry, X-ray diffraction analysis and microhardness measurements. The main calorimetric peaks were identified to be due to ???, ?? and Q? phases precipitation. The hardening during aging at room temperature and 160°C, was respectively, explained by atomic clusters and GP zones formation and by GP zones and ???/?? phases coprecipitation. Although the mechanical properties variation during aging at 200°C is simple, the corresponding microstructural evolution is complex: on the basis of the DSC results, the increasing of microhardness values, is mainly due to the coprecipitation of GP zones and ???/?? phases, however, the maximum hardening is explained by the coexistence of ???/?? and ??? phases. Another important conclusion is that during aging at 160°C and 200°C, the ?? phase is essentially developed from GP zones.

Hayoune, Abdelali

2013-08-01

120

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

PubMed

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

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

2014-12-21

121

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

122

Total hemispherical emittance measured at high temperatures by the calorimetric method  

NASA Technical Reports Server (NTRS)

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

Difilippo, Frank; Mirtich, Michael J.; Banks, Bruce A.; Stidham, Curtis; Kussmaul, Michael

1989-01-01

123

Transport and calorimetric studies on CeNi2Al3  

NASA Astrophysics Data System (ADS)

Transport and calorimetric properties of Kondo lattice system CeNi2Al3 are reported. CeNi2Al3 shows good agreement with Grand Kadowaki-Woods relation with degeneracy of the quasi-particle N=6. The nonmagnetic nature of CeNi2Al3 is evident from resistivity measurement even though magnetic elements Ce and Ni are present. Three signatures, deviation from the normal metallic behaviour in resistivity above 140 K, relatively low charge carrier concentration (1021 cm?3) and energy gap Eg~11.6 meV obtained from two band model shed light on the most basic notions related to the semimetal nature of CeNi2Al3.

Y, Sankararao; Shanmukharao Samatham, S.; D, Venkateshwarlu; Gangrade, Mohan; Ganesan, V.

2014-09-01

124

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

Microsoft Academic Search

Concurrent calorimetric and interferometric studies have been conducted to investigate the effect that reduction of the base-plate\\u000a dimensions has on the steady-state performance of the rate of natural convection heat transfer from miniaturized horizontal\\u000a single plate-fin systems and plate-fin arrays. The effect was studied through comparison of the present results with those\\u000a of earlier relevant calorimetric, interferometric, or numerical studies.

Filino Harahap; Herry Lesmana; Poetro Lebdo Sambegoro

2010-01-01

125

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

126

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

127

Effect of Temperature on Xylanase II from Trichoderma reesei QM 9414: A Calorimetric, Catalytic, and Conformational Study  

PubMed Central

The secondary structure of xylanase II from Trichoderma reesei is lost in an apparent irreversible cooperative process as temperature is increased with a midpoint transition of 58.8 ± 0.1°C. The shift of the spectral centre of mass above 50°C is also apparently cooperative with midpoint transition of 56.3 ± 0.2°C, but the existence of two isofluorescent points in the fluorescence emission spectra suggests a non-two-state process. Further corroboration comes from differential scanning calorimetry experiments. At protein concentrations ?0.56?mg·mL?1 the calorimetric transition is reversible and the data were fitted to a non-two-state model and deconvoluted into six transitions, whereas at concentrations greater than 0.56?mg·mL?1 the calorimetric transition is irreversible with an exothermic contribution to the thermogram. The apparent Tm increased linearly with the scan rate according to first order inactivation kinetics. The effect of additives on the calorimetric transition of xylanase is dependent on their nature. The addition of sorbitol transforms reversible transitions into irreversible transitions while stabilizing the protein as the apparent Tm increases linearly with sorbitol concentration. d-Glucono-1,5-lactone, a noncompetitive inhibitor in xylanase kinetics, and soluble xylan change irreversible processes into reversible processes at high protein concentration. PMID:25276420

López, Gloria

2014-01-01

128

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

129

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

130

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

131

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

132

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

133

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

SciTech Connect

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

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

1981-11-01

134

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

135

Determining \\  

Microsoft Academic Search

A loss of passivity in the face of certain frequency dynamics (eg: high frequency dynamics) given an otherwise passive system leads to the notion of a “mixed” system. A “mixed” system is one that has a concept of small gain associated with it over those frequency intervals where passivity is lost. In this paper, a test for determining “mixedness” for

Wynita M. Griggs; Brian D. O. Anderson; Robert N. Shorten

2010-01-01

136

Determinants  

NSDL National Science Digital Library

Created by Lewis Blake and Stephanie Fitchett of the Connected Curriculum Project, the purposes of this module are to explore the properties of determinants of matrices and to develop an important theoretical formula. This is part of a larger collection of material hosted by Duke University.

Blake, Lewis; Fitchett, Stephanie

2010-05-19

137

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

138

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

SciTech Connect

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

Kabadi, V.N.

1992-10-01

139

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. PMID:19361339

Gentili, Rodolfo; Gentili, Elio; Sgorbati, Sergio

2009-01-01

140

Investigation of ferroelectric phase transitions of water in nanoporous silicates in simultaneous electrical noise and calorimetric measurements  

NASA Astrophysics Data System (ADS)

The phase transitions of water in the nanoporous silicate materials SBA-15 and MCM-41 with an ordered system of cylindrical pores have been investigated. Measurements of low-frequency electrical noises (Barkhausen noises) in the frequency range of 1-100 Hz have been performed simultaneously with relative calorimetric measurements. It has been found that the voltage of electrical fluctuations increases approximately 100 times in the temperature range from -30 to -50°C, which is associated with the first-order and second-order ferroelectric phase transitions. It has been assumed that the ferroelectric ice XI can be formed in capillary pores of the materials under investigations.

Bordonskiy, G. S.; Orlov, A. O.

2014-08-01

141

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

PubMed

This paper describes the modelisation of the Elekta XVI Cone Beam Computed Tomography (CBCT) machine components with Geant4 and its validation against calibration data taken for two commonly used machine setups. Preliminary dose maps of simulated CBCTs coming from this modelisation work are presented. This study is the first step of a research project, GHOST, aiming to improve the understanding of late toxicity risk in external beam radiotherapy patients by simulating dose depositions integrated from different sources (imaging, treatment beam) over the entire treatment plan. The second cancer risk will then be derived from different models relating irradiation dose and second cancer risk. PMID:25415354

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

2014-11-21

142

XVI. On the distribution of electric force and rise of temperature in the glow discharge  

Microsoft Academic Search

1. 1. It is suggested that the results of Messrs. Finch and Cowen's experiments upon gaseous combustion and ignition in electric discharges might be explained equally well upon the thermal theory.2. 2. Experiments made to test the accuracy of the two-probe method of' determining the electric force in glow discharges are described. These lead to the conclusion that above a

John M. Holm

1931-01-01

143

Calorimetric determination of the angular dependent phase diagram of an S=1/2 Heisenberg triangular-lattice antiferromagnet  

NASA Astrophysics Data System (ADS)

An antiferromagnetic system on a 2-D triangular lattice leads to geometric topological frustration. This ideal system has been the subject of theoretical investigations. One experimental realization of this system is the compound Cs2CuCl4. Various magnetization, heat capacity, neutron scattering and NMR studies have identified several magnetic transitions when the magnetic field is applied along one of the three principal axes. The current work investigates the evolution of these phases at intermediate angles as the crystal is rotated relative to the magnetic field. These phases were investigated using a novel rotating calorimeter allowing complete coverage of the experimental parameter space. New magnetic phases only existing at intermediate angles have been found.

Hannahs, S. T.; Fortune, N. A.; Park, J.-H.; Takano, Y.; Ono, T.; Tanaka, H.

2014-12-01

144

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

145

Calorimetric and optical microscopic studies on one ferroelectric liquid-crystal compound with the smectic-A/emph> phase  

NASA Astrophysics Data System (ADS)

Detailed calorimetric measurements have been carried out on the chiral and racemic versions of one chiral liquid-crystal compound that exhibits an unusual and new smectic-A* (Sm-A*) phase in the pure chiral compound. Both the smectic-A (Sm-A)-smectic-C (Sm-C) transition in the racemic compound and the Sm-A*-chiral-Sm-C transition in the pure chiral compound display a first-order transition with heat-capacity anomalies qualitatively similar to but quantitatively different from that observed in the ordinary Sm-A-Sm-C transition. Results from optical microscopic studies on the phase diagram of binary mixtures of the dextro and levo versions of the chiral compounds are reported.

Huang, C. C.; Lin, D. S.; Goodby, J. W.; Waugh, M. A.; Stein, S. M.; Chin, E.

1989-10-01

146

Population and habitat on the feudal domain iria at the beginning of the XVIth century Eugen Ghita Populaie i habitat pe domeniul cetii iria la nceputul secolului al XVI lea  

E-print Network

Population and habitat on the feudal domain iria at the beginning of the XVIth century Eugen Ghita domeniul cetii iria la începutul secolului al XVI ­lea Eugen Ghi Abstract: The study ,,Population and habitat on the feudal domain iria at the beginning of the XVIth century Eugen Ghita Populaie i habitat pe

Paris-Sud XI, Université de

147

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

148

Electromagnetic and calorimetric measurements for AC losses of a YBa2Cu3O7-delta coated conductor with Ni-alloy substrate  

Microsoft Academic Search

The AC losses of a rolling-assisted-biaxially-textured-substrate (RABiTS™) processed YBa2Cu3O7-delta (YBCO) coated conductor (Goyal et al 1996 Appl. Supercond. 4 403-27) with Ni-alloy substrate and Cu stabilizer were measured at 77 K by both calorimetric (CM) and electromagnetic (EM) methods. In the CM method, improvements in the measurement were observed when a Cernox temperature sensor was used to measure the temperature

D. N. Nguyen; P. V. P. S. S. Sastry; D. C. Knoll; J. Schwartz

2006-01-01

149

Electromagnetic and calorimetric measurements for AC losses of a YBa2Cu3O7?? coated conductor with Ni-alloy substrate  

Microsoft Academic Search

The AC losses of a rolling-assisted-biaxially-textured-substrate (RABiTS™) processed YBa2Cu3O7?? (YBCO) coated conductor (Goyal et al 1996 Appl. Supercond. 4 403–27) with Ni-alloy substrate and Cu stabilizer were measured at 77 K by both calorimetric (CM) and electromagnetic (EM) methods. In the CM method, improvements in the measurement were observed when a Cernox temperature sensor was used to measure the temperature

D N Nguyen; P V P S S Sastry; D C Knoll; J Schwartz

2006-01-01

150

Isothermal calorimetric investigation of a reversible reaction in rapidly solidified Fe/sub 40/Fi/sub 40/B/sub 20/  

SciTech Connect

A new method is described for isothermal calorimetric measurement of time-dependent reversible reactions in which the rate of heat flow is small compared to the noise and zero drift of the measurement. Results using this method are presented which measure enthalpy changes associated with reversible phase changes in a rapidly solidified Fe/sub 40/Ni/sub 40/B/sub 20/ alloy.

Cost, J.R.; Elliott, R.O.; Stanley, J.T.

1983-01-01

151

Slovenica XVI—XIX ??. ? ?????? ??????? ?????????? ?????????? (??????????) ???????????? (? ????????????????? ?????????????)  

E-print Network

University possesses the necessary materials for research on the history of the Slovene language. SLOVENE: Znanstvena knjižnica Univerze v Tartuju, ki danes obsega ve? kot pet milijonov enot, je bila ustanovljena leta 1802. V njej je med drugim tudi ve? knjig...

Dulichenko, Aleksandr D.

2001-01-01

152

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

153

Detection of nitrite and nitrosocompounds in chemical systems and biological liquids by the calorimetric method  

Microsoft Academic Search

The capacity of nitrite, S-nitrosothiols (RS-NO), dinitrosyl iron complexes (DNICs) with thiolcontaining ligands, and nitrosoamines\\u000a to inhibit catalase has been used for the selective determination of these compounds in purely chemical systems and biological\\u000a liquids: cow milk and colostrum. The limiting sensitivity of the method is 50 nM. A comparison of the results of the determinations\\u000a of RS-NO, DNIC, and

V. Yu. Titov; Yu. M. Petrenko; A. F. Vanin; I. I. Stepuro

2010-01-01

154

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. PMID:15930003

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

2005-01-01

155

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

156

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

157

Calorimetric study of calcium aluminate cement blended with flue gas desulfurization gypsum  

Microsoft Academic Search

The use of by-product gypsum is an important alternative in concrete design. In present experiment, conduction calorimetry\\u000a was applied to investigate the early hydration of calcium aluminate cement (CAC)\\/flue gas desulfurization (FGD) gypsum paste,\\u000a supplemented with the determination of setting times and analysis of hydrates by X-ray diffraction (XRD). It was found that\\u000a different profiles of heat evolution rate were

Baohong Guan; Wenbin Lou; Qingqing Ye; Hailu Fu; Zhongbiao Wu

2009-01-01

158

Comparative spectroscopic, calorimetric, and computational studies of nucleic acid complexes with 2',5"-versus 3',5"-phosphodiester linkages.  

PubMed

We have used a combination of spectroscopic, calorimetric, and computational techniques to characterize the properties of nucleic acid complexes with 2',5''- and 3',5''-phosphodiester linkages. Specifically, we have compared the properties of complexes formed by the association of 3',5'' single-stranded 16-mers of adenylic acid (A16) and thymidylic acid (T16) with the complexes formed by the corresponding single-stranded 16-mers with 2',5''-phosphodiester linkages (A*16 and T*16). Our results reveal the following differential features: (i) the 3',5'' strands form either a duplex or a triplex, depending on the sodium ion concentration, whereas the 2',5'' strands form either a triplex or no complex at all; (ii) the 2',5'' and 3',5'' triplexes exhibit significantly different CD spectra, suggesting that the two triplex states are conformationally nonequivalent; (iii) the 2',5'' triplex has a lower charge density than the 3',5'' triplex; (iv) the thermal stability of the 3',5'' triplex, as expected, is concentration dependent, whereas the thermal stability of the 2',5'' triplex is concentration independent; (v) relative to their component single strands, the 2',5'' triplex is thermodynamically much less stable than the 3',5'' triplex, despite being thermally more stable; (vi) the reduced thermodynamic stability of the 2',5'' triplex relative to the 3',5'' triplex is overwhelmingly enthalpic in origin. In the aggregate, our results reveal and characterize significant differences in the properties of complexes formed by the association of strands with identical base sequences but different phosphodiester linkages. We describe a structural model that is consistent with many of the differential properties observed. We also speculate on how these differential properties may have provided an evolutionary advantage for 3',5'' linkages and how the properties of 2',5'' complexes might be exploited in antisense strategies. PMID:8248146

Jin, R; Chapman, W H; Srinivasan, A R; Olson, W K; Breslow, R; Breslauer, K J

1993-11-15

159

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

PubMed

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

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

2013-01-01

160

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

161

Spectroscopic and calorimetric studies on the binding of alkaloids berberine, palmatine and coralyne to double stranded RNA polynucleotides.  

PubMed

The interaction of two natural protoberberine plant alkaloids berberine and palmatine and a synthetic derivative coralyne to three double stranded ribonucleic acids, poly(A). poly(U), poly(I).poly(C) and poly(C).poly(G) was studied using various biophysical techniques. Absorbance and fluorescence studies showed that the alkaloids bound cooperatively to these RNAs with the binding affinities of the order 10(4) M(-1). Circular dichroic results suggested that the conformation of poly(A). poly(U) was perturbed by all the three alkaloids, that of poly(I).poly(C) by coralyne only and that of poly(C).poly(G) by none. Fluorescence quenching studies gave evidence for partial intercalation of berberine and palmatine and complete intercalation of coralyne to these RNA duplexes. Isothermal titration calorimetric studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the affinity constants derived were in agreement with the overall binding affinity from spectral data. The binding of all the three alkaloids considerably stabilized the melting of poly(A). poly(U) and poly(I).poly(C) and the binding data evaluated from the melting data were in agreement with that obtained from other techniques. The overall binding affinity of the alkaloids to these double stranded RNAs varied in the order, berberine = palmatine < coralyne. The temperature dependence of the enthalpy changes afforded large negative values of heat capacity changes for the binding of palmatine and coralyne to poly(A).poly(U) and of coralyne to poly(I).poly(C), suggesting substantial hydrophobic contribution in the binding process. Further, enthalpy-entropy compensation was also seen in almost all the systems that showed binding. These results further advance our understanding on the binding of small molecules that are specific binders to double stranded RNA sequences. PMID:19132839

Islam, Md Maidul; Chowdhury, Sebanti Roy; Kumar, Gopinatha Suresh

2009-01-29

162

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). PMID:24926102

Benisek, Artur; Dachs, Edgar

2013-01-01

163

[Calorimetric assay of yeast inorganic pyrophosphatase interaction with magnesium and phosphate ions].  

PubMed

The thermodynamic characteristics for the specific binding of one or two Mg2+ by the yeast inorganic pyrophosphatase and for the enzyme interaction with phosphate were determined. Saturation of the first binding site with Mg2+ causes structural rearrangements in the enzyme molecule without changing the temperature of protein denaturation. On the contrast, saturation of the second binding site results in stabilization of the system, i. e. a considerable fall in the entropy and a rise in the temperature of denaturation. Phosphorylation of the enzyme carboxylic group by inorganic phosphate requires saturation of the first binding site with Mg2+ and is not accompanied by changes in the enthalpy of the system. The pyrophosphate synthesis in the presence of the enzyme saturated with Mg2+ in both binding sites is associated with changes in the enthalpy and, possibly, in the entropy of the system. PMID:6124280

Vorob'eva, N N; Nazarova, T I; Bakuleva, N P; Avaeva, S M; Protasevich, I I

1982-05-01

164

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

165

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

PubMed

In this study, we use solubility and drop-solution calorimetry measurements to determine the thermodynamic properties of the uranyl phosphate phases autunite, uranyl hydrogen phosphate, and uranyl orthophosphate. Conducting the solubility measurements from both supersaturated and undersaturated conditions and under different pH conditions rigorously demonstrates attainment of equilibrium and yields well-constrained solubility product values. We use the solubility data and the calorimetry data, respectively, to calculate standard-state Gibbs free energies of formation and standard-state enthalpies of formation for these uranyl phosphate phases. Combining these results allows us also to calculate the standard-state entropy of formation for each mineral phase. The results from this study are part of a combined effort to develop reliable and internally consistent thermodynamic data for environmentally relevant uranyl minerals. Data such as these are required to optimize and quantitatively assess the effect of phosphate amendment remediation technologies for uranium contaminated systems. PMID:19848155

Gorman-Lewis, Drew; Shvareva, Tatiana; Kubatko, Karrie-Ann; Burns, Peter C; Wellman, Dawn M; Mcnamara, Bruce; Szymanowski, Jennifer E S; Navrotsky, Alexandra; Fein, Jeremy B

2009-10-01

166

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

PubMed

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

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

2008-10-16

167

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

168

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

169

Calorimetric study and thermal analysis of [ErY(Ala) 4 (H 2 O) 8 ](ClO 4 ) 6 ( Ala =ALANINE)  

Microsoft Academic Search

A solid complex of rare-earth compounds with alanine, [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry\\u000a and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)4(H2O)8](ClO4)6 was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid\\u000a phase transition was found between 99 and

B. P. Liu; Z. C. Tan; Z. D. Nan; P. Liu; L. X. Sun; F. Xu; X. Z. Lan

2003-01-01

170

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. PMID:23814314

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

2013-01-01

171

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

PubMed

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

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

2008-05-01

172

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

PubMed

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

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

2008-08-14

173

Calorimetric and computational study of 1,3- and 1,4-oxathiane sulfones.  

PubMed

The enthalpies of formation in the condensed and gas states, DeltafH degrees m(cd) and DeltafH degrees m(g), of 1,3- and 1,4-oxathiane sulfones were derived from their respective enthalpies of combustion in oxygen, measured by a rotating bomb calorimeter and the variation of vapor pressures with temperatures determined by the Knudsen effusion technique. Standard ab initio molecular orbital calculations at the G2(MP2) and G3 levels were performed, and a theoretical study on molecular and electronic structure of the compounds has been carried out. Calculated DeltafH degrees m(g) values at the G3 level using atomization reactions agree well with the experimental ones. These experimental and theoretical studies support that the destabilization found in 1,3-oxathiane sulfone, 11.2 kJ mol-1 respecting to 1,4-oxathiane sulfone, is due to the electrostatic repulsion between the negative charges of the axial oxygen of the sulfone and the oxygen of the ring and apparently masks any stabilization originating from the hyperconjugative nO --> sigma*C-SO2 stereoelectronic interaction. PMID:17288369

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

2007-02-16

174

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

175

Effect of lamellarity and size on calorimetric phase transitions in single component phosphatidylcholine vesicles.  

PubMed

Nano-differential scanning calorimetry (nano-DSC) is a powerful tool in the investigation of unilamellar (small unilamellar, SUVs, or large unilamellar, LUVs) vesicles, as well as lipids on supported bilayers, since it measures the main gel-to-liquid phase transition temperature (Tm), enthalpies and entropies. In order to assign these transitions in single component systems, where Tm often occurred as a doublet, nano-DSC, dynamic light scattering and cryo-transmission electron microscopy (cryo-TEM) data were compared. The two Tms were not attributable to decoupled phase transitions between the two leaflets of the bilayer, i.e. nano-DSC measurements were not able to distinguish between the outer and inner leaflets of the vesicle bilayers. Instead, the two Tms were attributed to mixtures of oligolamellar and unilamellar vesicles, as confirmed by cryo-TEM images. Tm for the oligolamellar vesicles was assigned to the peak closest to that of the parent multilamellar vesicle (MLV) peak. The other transition was higher than that of the parent MLVs for 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), and increased in temperature as the vesicle size decreased, while it was lower in temperature than that of the parent MLVs for 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and decreased as the vesicle size decreased. These subtle shifts arose due to small differences in the values of ?H and ?S, since Tm is determined by their ratio (?H/?S). It was not possible to completely eliminate oligolamellar structures for MLVs extruded with the 200nm pore size filter, even after 120 passes, while these structures were eliminated for MLVs extruded through the 50nm pore size filter. PMID:25445167

Drazenovic, Jelena; Wang, Hairong; Roth, Kristina; Zhang, Jiangyue; Ahmed, Selver; Chen, Yanjing; Bothun, Geoffrey; Wunder, Stephanie L

2015-02-01

176

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

SciTech Connect

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

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

2009-10-01

177

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

178

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

179

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

180

Magnetic, Calorimetric, and Transport Studies of Coupling and Interstrand Contact Resistance in Nb3Sn Rutherford Cables with Bimetallic Cores of Stainless Steel Bonded to Copper  

NASA Astrophysics Data System (ADS)

Magnetic and calorimetric techniques were used to measure coupling loss in small-scale (typically 20-strand) Rutherford cables inclosing bimetallic stainless steel-and-copper cores. The effects of two types of core were studied: (i) a double core consisting of two strips of bimetallic Cu/SS with the stainless steel (SS) surfaces facing each other; (ii) a single composite core with Cu sandwiched between two strips of SS — a kind of "thick-core reference". A "no-core reference" cable was also included in the measurement set. In the double-core cable the facing SS strips (with their included surface oxide layer) were intended to inhibit crossover interstrand contact at the same time that side-by-side contact would be enhanced by the diffusion bonding of the outer strip surfaces to the strand during the cable's prolonged heat treatment under a uniaxial pressure of 20 MPa. Coupling loss in this double-core cable was small but measurable and very much less than that of the uncored cable. Coupling loss in the composite core cable was immeasurably small. The losses were expressed quantitatively in terms of interstrand contact resistances (ICR) deduced from the magnetic- and calorimetric coupling-loss results. ICR data were also obtained by direct measurement using the four-terminal transport method.

Sumption, M. D.; Scanlan, R. M.; Illyin, Yu. A.; Nijhuis, A.; Collings, E. W.

2004-06-01

181

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

182

Micromechanical calorimetric sensor  

DOEpatents

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

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

2000-01-01

183

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

184

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

NASA Astrophysics Data System (ADS)

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

Bayer Corporation

2014-10-01

185

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. PMID:17293402

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

2007-01-01

186

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

187

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

188

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

SciTech Connect

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 (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c^2.

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, Priscilla B.; Daal, M.; Di Stefano, P. C.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, Jeter C.; 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.; Redi, P.; Reisetter, A.; Ricci, Y.; Saab, T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, Richard; 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.

2014-01-27

189

Analysis of protein-surfactant interactions--a titration calorimetric and fluorescence spectroscopic investigation of interactions between Humicola insolens cutinase and an anionic surfactant.  

PubMed

We have studied interactions of cutinase (HiC) from Humicula insolens and sodium dodecyl sulphate (SDS) by parallel calorimetric and fluorescence investigations of systems in which the concentration of both components was changed systematically. Results from the two methods exhibit a number of synchronous characteristics, when plotted against the total SDS concentration, [SDS]tot. The molecular origin of several of these anomalies was assigned, and five intervals of [SDS]tot in which different modes of interactions dominated were identified. Going from low to high [SDS]tot, these modes were: binding of (a few) SDS to native HiC, formation of oligomeric protein aggregates, denaturation of HiC and adsorption of SDS on denatured protein. For [SDS]tot>3-6 mM (depending on the protein concentration), the adsorption saturated, and no further protein-detergent interaction could be detected. Two particularly conspicuous anomalies in the calorimetric data were ascribed to respectively denaturation and saturation. It was found that [SDS]tot at these points depended linearly on the (total) protein concentration, [HiC]. We suggest that this reflects the balance between bound and free SDS [SDS]tot=[SDS]aq+[HiC] Nb where [SDS]aq and Nb are, respectively, the aqueous ("free") concentration of SDS and the average number of SDS bound per protein. Interpretation of the results along these lines showed that at 22 degrees C and pH 7.0, HiC denatures with approximately 14 bound surfactant molecules at [SDS]aq=1.0 mM. Saturation is characterized by Nb approximately 39 and [SDS]aq=2.2 mM. The latter value is equal to CMC in the (protein free) buffer. These results are discussed with respect to the SDS-binding capacity of HiC and the origin and location of the saturation point. PMID:16162423

Nielsen, Anders D; Arleth, Lise; Westh, Peter

2005-09-25

190

A calorimetric determination of the enthalpy of formation and a description of the defect structure of the ordered beta-phase /Ni, Cu/ /1-x/ Al/x/  

NASA Technical Reports Server (NTRS)

In order to describe thermodynamically the defect structure of an ordered B-Hume-Rothery phase, the heat of formation of (Ni,Cu)(1-x)Al(x) was measured at 1100 K as a function of concentration in the range x (sub Al) = 0.4 and 0.55 for three substitution rations x (sub Ni)/x (sub Cu) = infinity; 11; 5. The heat of formation of the NiAl beta-phase is strongly negative. For the stoichiometric composition it is -72.2 kJ/g-atom. On both the nickel-rich side and the aluminum-rich side the magnitude of the enthalpy of formation decreases linearly with concentration. Substitution of nickel for copper decreases the magnitude of the enthalpy of formation over the entire homogeneity range for the phase (Ni,Cu)(1-x)Al(x). The curve for the enthalpy of formation as well as the literature values for the chemical potential of aluminum are described with great accuracy by the disorder model of Wagner-Schottky.

Henig, E. T.; Lukas, H. L.

1988-01-01

191

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. PMID:11023908

Lewis, R N; McElhaney, R N

2000-01-01

192

CHAPTER XVI TUNICATES AND LANCELETS  

E-print Network

to the vertebrates and are included with them in the phYlum Chordata to which the higher animals, InclUding man, belong. In modern classifications they are given the rank vf a subphylum of the Chordata. They are

193

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

194

ALLELOPATHIC PLANTS. XVI. ARTEMISIA SPECIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

195

Electromagnetic and calorimetric measurements for AC losses of a YBa2Cu3O7-? coated conductor with Ni-alloy substrate  

NASA Astrophysics Data System (ADS)

The AC losses of a rolling-assisted-biaxially-textured-substrate (RABiTS™) processed YBa2Cu3O7-? (YBCO) coated conductor (Goyal et al 1996 Appl. Supercond. 4 403-27) with Ni-alloy substrate and Cu stabilizer were measured at 77 K by both calorimetric (CM) and electromagnetic (EM) methods. In the CM method, improvements in the measurement were observed when a Cernox temperature sensor was used to measure the temperature rise on the sample instead of a differential thermocouple. The effect of heat transferred from current leads was taken into account to improve the accuracy of the CM results. In the EM method, the magnetization losses of the sample in a perpendicular applied field were measured by an in-plane pick-up coil. The calculation of the calibration factor C of the pick-up coil is discussed. Good agreement between AC loss results obtained from the CM and EM methods confirmed the validity of our measurements and calculations.

Nguyen, D. N.; Sastry, P. V. P. S. S.; Knoll, D. C.; Schwartz, J.

2006-10-01

196

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

PubMed

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

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

2012-04-01

197

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

NASA Astrophysics Data System (ADS)

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

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

198

Spectrophotometric and Calorimetric Studies of Np(V) Complexation with Acetate at Variable Temperatures (T = 283 - 343 K)  

SciTech Connect

Spectrophotometric titrations were performed to identify the Np(V)/acetate complex and determine the equilibrium constants at variable temperatures (T = 283 - 343 K) and at the ionic strength of 1.05 mol {center_dot} kg{sup -1}. The enthalpy of complexation at corresponding temperatures was determined by microcalorimetric titrations. Results show that the complexation of Np(V) with acetate is weak but strengthened as the temperature is increased. The complexation is endothermic and is entropy-driven. The enhancement of the complexation at elevated temperatures is primarily due to the increasingly larger entropy gain when the solvent molecules are released from the highly-ordered solvation spheres of NpO{sub 2}{sup +} and acetate to the bulk solvent where the degree of disorder is higher at higher temperatures.

Rao, Linfeng; Tian, Guoxin; Srinivasan, Thandankorai G.; Zanonato, PierLuigi; Di Bernardo, Plinio

2009-12-21

199

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)=0.1 MPa) 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)kJ mol(-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

200

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

201

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

PubMed

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

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

2006-03-31

202

Calorimetric and computational study of 1,3-dithiacyclohexane 1,1-dioxide (1,3-dithiane sulfone).  

PubMed

The enthalpies of combustion and sublimation of 1,3-dithiacyclohexane 1,1-dioxide (1,3-dithiane sulfone) were measured by a rotating-bomb combustion calorimeter and the Knudsen effusion technique, and the gas-phase enthalpy of formation was determined, Delta(f)H(m)*(g) = -326.3 +/- 2.0 kJ mol(-1). Standard ab initio molecular orbital calculations at the G2(MP2) level were performed, and a theoretical study on molecular and electronic structure of the compound has been carried out. Calculated Delta(f)H(m)*(g) values agree very well with the experimental one. These experimental and theoretical studies support the relevance of the repulsive electrostatic interaction between sulfur atoms in 1,3-dithiane sulfone, that apparently counterbalances any n(S) --> rho(C-SO2)* stabilizing hyperconjugative interaction. PMID:14987027

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

2004-03-01

203

Entropy-driven folding of an RNA helical junction: an isothermal titration calorimetric analysis of the hammerhead ribozyme.  

PubMed

Helical junctions are extremely common motifs in naturally occurring RNAs, but little is known about the thermodynamics that drive their folding. Studies of junction folding face several challenges: non-two-state folding behavior, superposition of secondary and tertiary structural energetics, and drastically opposing enthalpic and entropic contributions to folding. Here we describe a thermodynamic dissection of the folding of the hammerhead ribozyme, a three-way RNA helical junction, by using isothermal titration calorimetry of bimolecular RNA constructs. By using this method, we show that tertiary folding of the hammerhead core occurs with a highly unfavorable enthalpy change, and is therefore entropically driven. Furthermore, the enthalpies and heat capacities of core folding are the same whether supported by monovalent or divalent ions. These properties appear to be general to the core sequence of bimolecular hammerhead constructs. We present a model for the ion-induced folding of the hammerhead core that is similar to those advanced for the folding of much larger RNAs, involving ion-induced collapse to a structured, non-native state accompanied by rearrangement of core residues to produce the native fold. In agreement with previous enzymological and structural studies, our thermodynamic data suggest that the hammerhead structure is stabilized in vitro predominantly by diffusely bound ions. Our approach addresses several significant challenges that accompany the study of junction folding, and should prove useful in defining the thermodynamic determinants of stability in these important RNA motifs. PMID:15134461

Mikulecky, Peter J; Takach, Jennifer C; Feig, Andrew L

2004-05-18

204

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

205

Thermochemistry of 1,3-dithiacyclohexane 1-oxide (1,3-dithiane sulfoxide): calorimetric and computational study.  

PubMed

The enthalpies of combustion and sublimation of 1,3-dithiacyclohexane 1-oxide (1,3-dithiane sulfoxide, 2) were measured by a rotating-bomb combustion calorimeter and the Knudsen effusion technique, and the gas-phase enthalpy of formation was determined, DeltafH degrees m(g) = -98.0 +/- 1.9 kJ mol(-1). This value is not as large (negative) as could have been expected from comparison with thermochemical data available for the thiane/thiane oxide reference system. High-level ab initio molecular orbital calculations at the MP2(FULL)/6-31G(3df,2p) level were performed, and the optimized molecular and electronic structures of 2 afforded valuable information on (1) the relative conformational energies of 2-axial and 2-equatorial--the latter being 7.1 kJ mol(-1) more stable than 2-axial, (2) the possible involvement of nS --> sigma*(C-S(O)) hyperconjugation in 2-equatorial, (3) the lack of computational evidence for sigma(S-C) --> sigma*(S-O) stereoelectronic interaction in 2-equatorial, and (4) the relevance of a repulsive electrostatic interaction between sulfur atoms in 1,3-dithiane sulfoxide, which apparently counterbalances any nS --> sigma*(C-S(O)) stabilizing hyperconjugative interaction and accounts for the lower than expected enthalpy of formation for sulfoxide 2. PMID:15287796

Roux, María Victoria; Temprado, Manuel; Jiménez, Pilar; Dávalos, Juan Z; Notario, Rafael; Martín-Valcárcel, Gloria; Garrido, Leoncio; Guzmán-Mejía, Ramón; Juaristi, Eusebio

2004-08-01

206

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

207

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

208

Calorimetric study of cationic photopolymerization  

NASA Astrophysics Data System (ADS)

The photopolymerization of penta-erythritol tetra-glycidyl ether (initiator Degacure KI-85) was studied by a du Pont 910 type DSC. From our experimental results the following conclusions can be drawn: (1) During the cationic polymerization reaction the lifetime of the initiating centers are long compared to the lifetime of free radicals in case of radical polymerization. (2) The rate of deactivation of the initiating centers increases with increasing temperature.

Czajlik, I.; Hedvig, P.; Ille, A.; Dobó, J.

1996-03-01

209

Enthalpy Determination for Ground Testing Conditions in Plasma Wind Tunnel  

NASA Astrophysics Data System (ADS)

The re-entry in atmosphere is one of the critical flight steps of a spacecraft. The kinetic energy that was accumulated during the entire flight must be dissipated into thermal energy in order to slow down the vehicle. Given the magnitude of the heat load during the re-entry phase, the vehicle must be protected by means of a thermal protection system. This problem can be studied in ground test facilities like the VKI plasmatron where the real flight heat transfer environment can be reproduced. In such a facility, the enthalpy is of prime importance because it is a parameter that enables the flight extrapolation of the test bench results. In this present study, two methods were considered for this purpose. On one hand, experimental measurements were taken with a new calorimetric probe which was designed at the VKI. A new method was also proposed to increase its sensitivity. This first part permits to take several enthalpy measurements at 20000 pa for a wide range of power. On the other hand, a heat flux based method for enthalpy determination was reviewed. Heat transfer measurements, main input of this method, were taken from a water cooled calorimeter and a thermal capacitance. They were then compared in order to assess their reliability. These probes were found to give the same measurements within their uncertainty range. En- thalpy rebuildings were thus performed using the water cooled calorimeter. Finally, a comparison of the calorimetric probe technique and the heat flux method was achieved and a good agreement was found, showing thus the reliability of all the VKI tools for stagnation point characterization.

Krassilchikoff, H.; Chazot, O.

2009-01-01

210

Conformational investigation of alpha,beta-dehydropeptides. XVI. Beta-turn tendency in Ac-Pro-DeltaXaa-NHMe: crystallographic and theoretical studies.  

PubMed

The crystal structures of two diastereomeric alpha,beta-dehydrobutyrine peptides Ac-Pro-(Z)-DeltaAbu-NHMe (I) and Ac-Pro-(E)-DeltaAbu-NHMe (II) have been determined. Both dehydropeptides adopt betaI-turn conformation characterized by the pairs of (phi(i+1), psi(i+1)) and (phi(i+2), psi(i+2)) angles as -66, -19, -97, 11 degrees for I and -59, -27, -119, 29 degrees for II. In each peptide, the betaI turn is stabilized by (i + 3) --> i intramolecular hydrogen bonds with N...O distance of 3.12 A for I and 2.93 A for II. These structures have been compared to the crystal structures of homologous peptides Ac-Pro-DeltaVal-NHMe and Ac-Pro-DeltaAla-NHMe. Theoretical analyses by DFT/B3LYP/6-31 + G** method of conformers formed by these four peptides and by the saturated peptide Ac-Pro-Ala-NHMe revealed that peptides with a (Z) substituent at the C(beta) (i+2) atom of dehydroamino acid, i.e. Ac-Pro-DeltaVal-NHMe and Ac-Pro-(Z)-DeltaAbu-NHMe, predominantly form beta turns, both in vacuo and in polar environment. The tendency to adopt beta-turn conformation is much weaker for the peptides lacking the (Z) substituent, Ac-Pro-(E)-DeltaAbu-NHMe and Ac-Pro-DeltaAla-NHMe. The latter adopts a semi-extended or an extended conformation in every polar environment, including a weakly polar solvent. The saturated peptide Ac-Pro-Ala-NHMe in vacuo prefers a beta-turn conformation, but in polar environment the differences between various conformers are small. The role of pi-electron correlation and intramolecular hydrogen bonds interaction in stabilizing the hairpin structures are discussed. PMID:16733828

Broda, Malgorzata A; Ciszak, Ewa M; Koziol, Anna E; Pietrzynski, Grzegorz; Rzeszotarska, Barbara

2006-08-01

211

Myosin cleft closure determines the energetics of the actomyosin interaction  

PubMed Central

Formation of the strong binding interaction between actin and myosin is essential for force generation in muscle and in cytoskeletal motor systems. To clarify the role of the closure of myosin's actin-binding cleft in the actomyosin interaction, we performed rapid kinetic, spectroscopic, and calorimetric experiments and atomic-level energetic calculations on a variety of myosin isoforms for which atomic structures are available. Surprisingly, we found that the endothermic actin-binding profile of vertebrate skeletal muscle myosin subfragment-1 is unique among studied myosins. We show that the diverse propensity of myosins for cleft closure determines different energetic profiles as well as structural and kinetic pathways of actin binding. Depending on the type of myosin, strong actin binding may occur via induced-fit or conformational preselection mechanisms. However, cleft closure does not directly determine the kinetics and affinity of actin binding. We also show that cleft closure is enthalpically unfavorable, reflecting the development of an internal strain within myosin in order to adopt precise steric complementarity to the actin filament. We propose that cleft closure leads to an increase in the torsional strain of myosin's central ?-sheet that has been proposed to serve as an allosteric energy-transducing spring during force generation.—Takács, B., O'Neall-Hennessey, E., Hetényi, C., Kardos, J., Szent-Györgyi, A. G., Kovács, M. Myosin cleft closure determines the energetics of the actomyosin interaction. PMID:20837775

Takács, Balázs; O'Neall-Hennessey, Elizabeth; Hetényi, Csaba; Kardos, József; Szent-Györgyi, Andrew G.; Kovács, Mihály

2011-01-01

212

Influence of temperature and excitation procedure on the athermal behavior of Nd3+-doped phosphate glass: Thermal lens, interferometric, and calorimetric measurements  

NASA Astrophysics Data System (ADS)

In this work, thermal and optical properties of the commercial Q-98 neodymium-doped phosphate glass have been measured at low temperature, from 50 to 300 K. The time-resolved thermal lens spectrometry together with the optical interferometry and the thermal relaxation calorimetry methods were used to investigate the glass athermal characteristics described by the temperature coefficient of the optical path length change, ds /dT. The thermal diffusivity was also determined, and the temperature coefficients of electronic polarizability, linear thermal expansion, and refractive index were calculated and used to explain ds /dT behavior. ds /dT measured via thermal lens method was found to be zero at 225 K. The results provided a complete characterization of the thermo-optical properties of the Q-98 glass, which may be useful for those using this material for diode-pumped solid-state lasers.

Astrath, N. G. C.; Barboza, M. J.; Medina, A. N.; Bento, A. C.; Baesso, M. L.; Silva, W. F.; Jacinto, C.; Catunda, T.

2009-10-01

213

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

214

Folding of an antibody variable domain in two functional conformations in vitro: calorimetric and spectroscopic study of the anti-ferritin antibody VL domain.  

PubMed

Understanding refolding pathways of recombinant antibody fragments is essential for efficient production of these proteins of high biomedical significance. The recombinant VL domain of mouse anti-human ferritin antibody F11 formed two distinct functional conformations obtained by refolding from bacterial inclusion bodies using two different procedures. Involvement of a dialysis step at pH 2-3 resulted in the VL-1 conformation with fluorescence of the highly conserved Trp-35 residue quenched by the spatially proximal disulfide bond. This conformation was identical to the 'native' VL domain folded in host cells and purified from the cytoplasm. In the absence of the acidic dialysis step, the VL domain adopted a previously unreported conformation, VL-2, that demonstrated prominent fluorescence due to a local structural disorder around Trp-35. Furthermore, VL-2 showed changes in secondary structure and significantly lower stability as determined by differential scanning calorimetry and denaturant-induced unfolding. While more flexible VL-2 binds human ferritin both in solution and after surface adsorption of the antibody domain, the VL-1 conformer needs an adsorption-induced conformational change to allow the access of ferritin to the antigen-binding site. Noteworthy, the two macroscopic conformations constitute kinetically trapped dimers and do not interconvert at elevated temperatures (3 weeks at 37 degrees C or 15 min at 60 degrees C), which indicates a high energetic barrier between them. As a major finding, this paper provides the first description for two stable and functional conformations of an antibody domain. PMID:17962224

Tsybovsky, Yaroslav; Shubenok, Denis V; Kravchuk, Zinaida I; Martsev, Sergey P

2007-10-01

215

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

216

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

PubMed

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

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

2009-04-01

217

The Energetics of Hematite Dissolution in Iron Ore Melts for Assimilation in Commercial Sintering Processes: In Situ High Temperature Calorimetric Studies  

NASA Astrophysics Data System (ADS)

Melting and crystallization of iron ores in mining applications are determined by the thermodynamic properties of the crystals and liquids in equilibrium. Iron ores are widely used for sinter production in Japan, Korea Russia, and Australia. In these sinter production plants, multiple ores can be blended together. Sintering is the second stage of a two step process in which iron ores fines, together with coke and flux material are converted into porous blocks of sinter that are suitable for direct feed into the blast furnace. The chemical and physical changes that occur during sintering are formation of granules, melt formation, assimilation and lastly crystallization. The initial stage involves the formation of granules in which small and intermediate sized particles adhere to larger nuclei via water bridging between adjacent particles. The second stage is known as assimilation; which involves the reaction between melt and un-melted iron ore particles during the sintering step. These ores are typically multi-component systems with numerous phases whose variability complicates industrial processing applications. High temperature calorimetry using molten iron-calcium-silicate solvents has been used to better understand and improve the industrial processing of iron ores, and evaluate the dissolution properties of Fe2O3 in a series of iron-oxide based melts at 1626 K. In the SFCA (silico-ferrite of calcium and aluminium) oxide mixture, the heat of solution of Fe2O3 for the first set of experiments is 52.5 b 10 kJ/mol as Fe2O3 concentration is increased from 59 to 64 mol%. The heat of solution was found to be strongly endothermic and independent of the liquid composition.

Navrotsky, A. A.; Morcos, R.; Ellis, B.

2006-12-01

218

Salt-specific effects observed in calorimetric studies of alkali and tetraalkylammonium salt solutions of poly(thiophen-3-ylacetic acid).  

PubMed

The enthalpies of dilution ?Hdil of aqueous solutions of a conjugated polyelectrolyte, poly(thiophen-3-ylacetic acid), neutralized by lithium, sodium, cesium, tetramethyl-, tetraethyl-, tetrapropyl-, and tetrabutylammonium hydroxides, were determined in the concentration range from cp = 2 × 10(-3) to 1 × 10(-1) monomol dm(-3) and for T = 278.15, 298.15, and 318.15 K. At low concentrations the dilution of the alkali PTAA salts yields an endothermic effect, which is in part a consequence of the hydrolysis. An exception is PTALi at 278.15 K, where ?Hdil < 0. In the case of tetraalkylammonium salts the enthalpies of dilution increase in the order TBA < TPA < TEA < TMA. Only the TBA salt of PTAA yields an exothermic effect upon dilution in the whole temperature range. In the second part of the study we measured the enthalpies of mixing, ?Hmix, of various salts of poly(thiophen-3-ylacetic acid) with LiCl, NaCl, KCl, and CsCl solutions in water. When lithium salt of PTAA is mixed with LiCl ?Hmix is positive. For mixing experiments with other alkali chlorides the effect is exothermic. In addition, the enthalpies of mixing of PTALi with tetramethyl-, tetraethyl-, tetrapropyl-, and tetrabutylammonium chloride were measured at T = 278.15 K, 298.15 K, and 318.15 K. Popular polyelectrolyte theories, such as Manning's limiting law, predict for the heat to be released upon dilution, and consumed upon mixing; the agreement between this purely electrostatic theory and experiments is at best qualitative. The ?Hmix values are correlated with the enthalpies of hydration of the cations of the low molecular mass salts added to the solution. PMID:25491322

Hostnik, Gregor; Vlachy, Vojko; Bondarev, Dmitrij; Vohlídal, Jir Combining Breve Í; Cerar, Janez

2015-01-28

219

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

220

Calorimetric investigation of copper binding in the N-terminal region of the prion protein at low copper loading: evidence for an entropically favorable first binding event.  

PubMed

Although the Cu(2+)-binding sites of the prion protein have been well studied when the protein is fully saturated by Cu(2+), the Cu(2+)-loading mechanism is just beginning to come into view. Because the Cu(2+)-binding modes at low and intermediate Cu(2+) occupancy necessarily represent the highest-affinity binding modes, these are very likely populated under physiological conditions, and it is thus essential to characterize them in order to understand better the biological function of copper-prion interactions. Besides binding-affinity data, almost no other thermodynamic parameters (e.g., ?H and ?S) have been measured, thus leaving undetermined the enthalpic and entropic factors that govern the free energy of Cu(2+) binding to the prion protein. In this study, isothermal titration calorimetry (ITC) was used to quantify the thermodynamic parameters (K, ?G, ?H, and T?S) of Cu(2+) binding to a peptide, PrP(23-28, 57-98), that encompasses the majority of the residues implicated in Cu(2+) binding by full-length PrP. Use of the buffer N-(2-acetomido)-aminoethanesulfonic acid (ACES), which is also a well-characterized Cu(2+) chelator, allowed for the isolation of the two highest affinity binding events. Circular dichroism spectroscopy was used to characterize the different binding modes as a function of added Cu(2+). The Kd values determined by ITC, 7 and 380 nM, are well in line with those reported by others. The first binding event benefits significantly from a positive entropy, whereas the second binding event is enthalpically driven. The thermodynamic values associated with Cu(2+) binding by the A? peptide, which is implicated in Alzheimer's disease, bear striking parallels to those found here for the prion protein. PMID:25541747

Gogineni, Devi Praneetha; Spuches, Anne M; Burns, Colin S

2015-01-20

221

A calorimetric study on the low temperature dynamics of doped ice V and its reversible phase transition to hydrogen ordered ice XIII.  

PubMed

Doped ice V samples made from solutions containing 0.01 M HCl (DCl), HF (DF), or KOH (KOD) in H(2)O (D(2)O) were slow-cooled from 250 to 77 K at 0.5 GPa. The effect of the dopant on the hydrogen disorder --> order transition and formation of hydrogen ordered ice XIII was studied by differential scanning calorimetry (DSC) with samples recovered at 77 K. DSC scans of acid-doped samples are consistent with a reversible ice XIII <--> ice V phase transition at ambient pressure, showing an endothermic peak on heating due to the hydrogen ordered ice XIII --> disordered ice V phase transition, and an exothermic peak on subsequent cooling due to the ice V --> ice XIII phase transition. The equilibrium temperature (T(o)) for the ice V <--> ice XIII phase transition is 112 K for both HCl doped H(2)O and DCl doped D(2)O. From the maximal enthalpy change of 250 J mol(-1) on the ice XIII --> ice V phase transition and T(o) of 112 K, the change in configurational entropy for the ice XIII --> ice V transition is calculated as 2.23 J mol(-1) K(-1) which is 66% of the Pauling entropy. For HCl, the most effective dopant, the influence of HCl concentration on the formation of ice XIII was determined: on decreasing the concentration of HCl from 0.01 to 0.001 M, its effectiveness is only slightly lowered. However, further HCl decrease to 0.0001 M drastically lowered its effectiveness. HF (DF) doping is less effective in inducing formation of ice XIII than HCl (DCl) doping. On heating at a rate of 5 K min(-1), kinetic unfreezing starts in pure ice V at approximately 132 K, whereas in acid doped ice XIII it starts at about 105 K due to acceleration of reorientation of water molecules. KOH doping does not lead to formation of hydrogen ordered ice XIII, a result which is consistent with our powder neutron diffraction study (C. G. Salzmann, P. G. Radaelli, A. Hallbrucker, E. Mayer, J. L. Finney, Science, 2006, 311, 1758). We further conjecture whether or not ice XIII has a stable region in the water/ice phase diagram, and on a metastable triple point where ice XIII, ice V and ice II are in equilibrium. PMID:18936855

Salzmann, Christoph G; Radaelli, Paolo G; Finney, John L; Mayer, Erwin

2008-11-01

222

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

223

Calorimetric measurement of energy of ultrasonic cleaners  

SciTech Connect

The development of a calorimeter that measured the power within an ultrasonic cleaning tank is presented. The principle involved is explained. Several types of calorimeter that were tested are described. Measurement of the power in an ultrasonic cleaner permits: (1) comparing different ultrasonic cleaners; (2) monitoring the performance of a specific cleaner; (3) measuring the distribution of power in a cleaning tank, and (4) evaluating the effects of process variables on the power.

Harding, W.B.

1994-11-01

224

Ch. 5 Determinants Determinant functions  

E-print Network

functions is n-linear. · Definition: D is n-linear. D is alternating if ­ (a) D(A)=0 if two rows a commutative ring with 1. D is a determinant function if D is n- linear, alternating and D(I)=1. (The aim since sum of two 2-linear functions · Alternating. Check (a), (b) above. · This is also unique: #12

Choi, Suhyoung

225

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.

226

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

227

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

228

Determination of the relaxation characteristics of sugar glasses embedded in microfiber substrates.  

PubMed

Recently there has been considerable interest in developing sugar glasses that enable storage of biologics without refrigeration. Microfiber filter papers are good substrates for drying biologics in the presence of sugar glass-formers, providing for an even distribution of samples and an enhanced surface area for drying, but the opaqueness prevents macroscopic observation of the sample and can introduce complexities that impede physical characterization. Because drying kinetics and processing conditions can impact the relaxation dynamics (e.g., ?- and ?-relaxation), which can influence the efficacy of the glass as a stabilizer, methods are needed that can enable a determination of relaxation phenomena of sugar glasses in such complex environments. In this study we present a method which provides verification of the absence of crystallinity following drying on glass fiber filter paper and also enables the determination of relaxation characteristics of amorphous sugar compositions embedded within these filter substrates. Using material pockets to contain the sugar glass-embedded microfiber paper, the ?-relaxation temperature, T?, was determined as a function of the water content in trehalose and sucrose samples using Dynamic Mechanical Analysis (DMA). Results were verified by comparison with previous calorimetric and spectroscopic studies. The data also demonstrated the plasticizing effects of water, as T? was shown to correlate with water content via a Gordon-Taylor-like relationship. Our findings validate a new approach for determining the relaxation characteristics of microfiber embedded sugar glasses, and offer new insights into the relaxation characteristics of glasses prepared by microwave-assisted drying on filter papers. PMID:25280724

Weng, Lindong; Elliott, Gloria D

2014-11-01

229

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

SciTech Connect

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

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

1993-09-01

230

An improved single crystal adsorption calorimeter for determining gas adsorption and reaction energies on complex model catalysts  

NASA Astrophysics Data System (ADS)

A new ultrahigh vacuum microcalorimeter for measuring heats of adsorption and adsorption-induced surface reactions on complex single crystal-based model surfaces is described. It has been specifically designed to study the interaction of gaseous molecules with well-defined model catalysts consisting of metal nanoparticles supported on single crystal surfaces or epitaxial thin oxide films grown on single crystals. The detection principle is based on the previously described measurement of the temperature rise upon adsorption of gaseous molecules by use of a pyroelectric polymer ribbon, which is brought into mechanical/thermal contact with the back side of the thin single crystal. The instrument includes (i) a preparation chamber providing the required equipment to prepare supported model catalysts involving well-defined nanoparticles on clean single crystal surfaces and to characterize them using surface analysis techniques and in situ reflectivity measurements and (ii) the adsorption/reaction chamber containing a molecular beam, a pyroelectric heat detector, and calibration tools for determining the absolute reactant fluxes and adsorption heats. The molecular beam is produced by a differentially pumped source based on a multichannel array capable of providing variable fluxes of both high and low vapor pressure gaseous molecules in the range of 0.005-1.5 × 1015 molecules cm-2 s-1 and is modulated by means of the computer-controlled chopper with the shortest pulse length of 150 ms. The calorimetric measurements of adsorption and reaction heats can be performed in a broad temperature range from 100 to 300 K. A novel vibrational isolation method for the pyroelectric detector is introduced for the reduction of acoustic noise. The detector shows a pulse-to-pulse standard deviation ?15 nJ when heat pulses in the range of 190-3600 nJ are applied to the sample surface with a chopped laser. Particularly for CO adsorption on Pt(111), the energy input of 15 nJ (or 120 nJ cm-2) corresponds to the detection limit for adsorption of less than 1.5 × 1012 CO molecules cm-2 or less than 0.1% of the monolayer coverage (with respect to the 1.5 × 1015 surface Pt atoms cm-2). The absolute accuracy in energy is within ˜7%-9%. As a test of the new calorimeter, the adsorption heats of CO on Pt(111) at different temperatures were measured and compared to previously obtained calorimetric data at 300 K.

Fischer-Wolfarth, Jan-Henrik; Hartmann, Jens; Farmer, Jason A.; Flores-Camacho, J. Manuel; Campbell, Charles T.; Schauermann, Swetlana; Freund, Hans-Joachim

2011-02-01

231

Study the penetration of IR laser radiation in human teeth: determination of the absorbed and scattered parts  

NASA Astrophysics Data System (ADS)

By using the developed by us approaches and instrumentation, we have obtained and presented series of systematized data, which are important for the use of the laser light in infrared (IR) spectral region. The obtained data include: 1) reflectivity of the human tooth dentin; 2) the spatial intensity distribution in the cross-section of the light beam penetrating the tooth's dentin; 3) the absorbed and the diffused parts of the laser light that have been determined separately through combination of optical and calorimetric techniques. The last result is the most important because it permits to calculate the dentin absorption and scattering coefficients. The study is performed for the laser light at two easily generated wavelengths - 1.06 ?m and 1.36 ?m, emitted by the Nd:YAG laser that is well known, commercially available, economical and widely used in many laboratories and medical institutions. The study is made on the basis of fresh in-vitro teeth samples from the persons of Bulgaria, Sofia region.

Uzunova, Pepa; Rabadgiiska, Stanislava; Uzunov, Tzonko; Kisov, Hristo; Kaimakanova, Nadejda; Deneva, Margarita; Dinkov, Emil; Nenchev, Marin

2013-03-01

232

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

233

25 CFR 36.43 - Standard XVI-Student activities.  

...MINIMUM ACADEMIC STANDARDS FOR THE BASIC EDUCATION OF INDIAN CHILDREN AND NATIONAL CRITERIA FOR DORMITORY SITUATIONS Instructional...competitive opportunities are provided to all students, regardless of sex, no student shall be barred from participation in...

2014-04-01

234

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2012 CFR

...MINIMUM ACADEMIC STANDARDS FOR THE BASIC EDUCATION OF INDIAN CHILDREN AND NATIONAL CRITERIA FOR DORMITORY SITUATIONS Instructional...competitive opportunities are provided to all students, regardless of sex, no student shall be barred from participation in...

2012-04-01

235

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2011 CFR

...MINIMUM ACADEMIC STANDARDS FOR THE BASIC EDUCATION OF INDIAN CHILDREN AND NATIONAL CRITERIA FOR DORMITORY SITUATIONS Instructional...competitive opportunities are provided to all students, regardless of sex, no student shall be barred from participation in...

2011-04-01

236

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2010 CFR

...MINIMUM ACADEMIC STANDARDS FOR THE BASIC EDUCATION OF INDIAN CHILDREN AND NATIONAL CRITERIA FOR DORMITORY SITUATIONS Instructional...competitive opportunities are provided to all students, regardless of sex, no student shall be barred from participation in...

2010-04-01

237

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2013 CFR

...MINIMUM ACADEMIC STANDARDS FOR THE BASIC EDUCATION OF INDIAN CHILDREN AND NATIONAL CRITERIA FOR DORMITORY SITUATIONS Instructional...competitive opportunities are provided to all students, regardless of sex, no student shall be barred from participation in...

2013-04-01

238

Chapter XVI Technology package for oat cultivation in Nepal  

Microsoft Academic Search

Summary Oats are a major winter fodder in most of Nepal and can be grown after summer crops, rice and maize, then harvested before the next cereal sowing season. The cool, dry winter is a major season of feed scarcity in Nepal. Only at very high altitudes about 3 000 metres are they sown in spring. The paper describes the

Laxmi P. Sharma; Subarna M. Pradhan

239

CHAPITRE XVI La porte de la voix parle et chante  

E-print Network

'efficacité vocale se traduit par l'émission d'une voix 1) qui porte 2) sans effort. Elle est sans doute une très un geste vocal spécifique : un abaissement laryngé constitue un des importants corrélats. Celui-ci est une véritable signature d'une voix qui porte sans effort. 2) « ... de n'en point prendre

Paris-Sud XI, Université de

240

Life Story of His Holiness the XVI Gyalwa Karmapa  

E-print Network

-lrm ~d th! V ~jra Oro'Nu cerem:>ny and gave empo- werments. His H)\\in'!ss then travelled to ReNJ.lsa.r (mTsho. Pad. Ma) in N')rth west India, which is sacred to Guru Padmasambhava. Many white snakes appe­ ared on the surface of the Rew.'11sar lake... as the sun and moon. From th:! First Karmlpa, DU'l.gsum.mkhyen.Pa, to th~ Fifteenth Karmapa, mKha. Khyab. rDo. rJe, they ha~e performed Dharma activites of H.H. Karmapa rD ).rJe, branched out their Dharma activities principally in Tibet, China...

Rinpoche, Jamgon Kongtrul

1982-01-01

241

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

Microsoft Academic Search

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

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

2011-01-01

242

DDD: Density Distribution Determination  

E-print Network

This paper presents a solution to the problem of determining the distribution of an absorbing substance inside a non-opaque non-scattering body from images or ray samplings. It simultaneously solves the problem of determining ...

Horn, Berthold K.P.

1973-03-08

243

Self-Determination.  

ERIC Educational Resources Information Center

This issue of "Transition Summary" contains articles about self-determination and becoming a good self-advocate, with each article reflecting the experience of someone who has grown up with a disability. "The Many Facets of Self-Determination" (Michael Ward) discusses the concept of self-determination; offers an historical perspective of the…

Transition Summary, 1988

1988-01-01

244

Nephelometric determination of fluorine  

USGS Publications Warehouse

Fluorine in minerals may be determined with the nephelometer to about 1 per cent of the fluorine. The determination is made on an aliquot of the sodium chloride solution of the fluorine, obtained by the Berzelius method of extraction. The fluorine is precipitated as colloidal calcium fluoride in alcoholic solution, gelatin serving as a protective colloid. Arsenates, sulfates, and phosphates, which interfere with the determination, must be removed.

Stevens, R.E.

1936-01-01

245

Equal Exchange: Determining a  

E-print Network

Equal Exchange: Determining a Fair Price for Carbon P E RS P E C T I V E S S E R I E S 20 07 #12;Equal Exchange: Determining a Fair Price for Carbon P e rs P e c t i v e s s e r i e s 20 07 Glenn Hodes. Printed on environmentally friendly paper. #12;editors' introduction Equal Exchange: Determining a Fair

246

Determinism without causality  

NASA Astrophysics Data System (ADS)

Causality has often been confused with the notion of determinism. It is mandatory to separate the two notions in view of the debate about quantum foundations. Quantum theory provides an example of causal non-deterministic theory. Here we introduce a toy operational theory that is deterministic and non-causal, thus proving that the two notions of causality and determinism are totally independent.

D?Ariano, G. M.; Manessi, F.; Perinotti, P.

2014-12-01

247

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

248

Determining Pregnancy in Cattle  

E-print Network

The process of palpating to determine pregnancy in cattle and the equipment used during palpation are described and illustrated in this bulletin. The female reproductive system is discussed, along with the developmental stages of the embryo/fetus....

Beverly, John R.; Sprott, L. R.; Carpenter, Bruce B.

2008-12-16

249

Ulysses orbit determination  

NASA Astrophysics Data System (ADS)

The Ulysses mission ESA spacecraft with ESA and NASA experiments explores the polar regions of the sun by sending a spacecraft on a trajectory out of the ecliptic after a Jupiter flyby. After correcting for launch errors and refining the aimpoint, orbit determination results show the change and general improvement in the Jupiter arrival point. Orbit determination results are further discussed, and future plans are mentioned.

Gordon, H. J.; Luthey, J. L.; McElrath, T. P.; Menon, P. R.

1992-08-01

250

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

251

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

252

A calorimetric study of thermal hysteresis effects in ganglioside micelles  

Microsoft Academic Search

Light, X-ray and neutron scattering measurements clearly showed strong temperature-related variations in micellar mean aggregation\\u000a number, accompanied by dramatic thermal hysteresis effects, for a variety of micelle-forming gangliosides. Gangliosides, sialic-acid-containing\\u000a glycosphingolipids, are amphiphilic molecules of biological origin with a ceramide (a double-tailed hydrophobic part, like\\u000a phospholipids) and an oligosaccharide chain as the headgroup. When temperature is varied in the range

L. Cantù; M. Corti; E. Del Favero; E. Muller; A. Raudino; S. Sonnino

253

Calorimetric studies of small-molecule adsorption to carbon nanotubes  

E-print Network

Isothermal titration calorimetry (ITC) was developed as a technique for qualitatively comparing the heat of absorption of small molecules to single-walled carbon nanotubes (SWCNTs). In agreement with other studies, it was ...

Glab, Kristin Lena

2009-01-01

254

RAPID COMMUNICATION: Calorimetric radar absorptivity measurement using a microwave oven  

NASA Astrophysics Data System (ADS)

The measurement of the microwave absorptivity of materials typically requires expensive and arcane equipment and methods. I show that, for moderately absorbing materials (loss tangent icons/Journals/Common/delta" ALT="delta" ALIGN="TOP"/>icons/Journals/Common/simeq" ALT="simeq" ALIGN="TOP"/>0.005 or higher), useful measurements can be easily made using a thermometer and a normal domestic microwave oven: the heat absorbed for suitably designed sample size and geometry relates directly to the absorptivity. This technique, although not supremely accurate, is quick and inexpensive and may be useful for rapid investigations, educational projects and situations in which samples are awkward to handle. I show that water ice spiked with even only 0.2% ammonia is about three orders of magnitude more absorbing than is pure ice at -80 °C.

Lorenz, Ralph D.

1999-06-01

255

Calorimetric radar absorptivity measurement using a microwave oven  

Microsoft Academic Search

The measurement of the microwave absorptivity of materials typically requires expensive and arcane equipment and methods. I show that, for moderately absorbing materials (loss tangent ' 0:005 or higher), useful measurements can be easily made using a thermometer and a normal domestic microwave oven: the heat absorbed for suitably designed sample size and geometry relates directly to the absorptivity. This

Ralph D Lorenz

256

RAPID COMMUNICATION: Calorimetric radar absorptivity measurement using a microwave oven  

Microsoft Academic Search

The measurement of the microwave absorptivity of materials typically requires expensive and arcane equipment and methods. I show that, for moderately absorbing materials (loss tangent icons\\/Journals\\/Common\\/delta\\

Ralph D. Lorenz

1999-01-01

257

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

258

Calorimetric investigations of phase transitions of sonicated vesicles of dimyristoylphosphatidylcholine.  

PubMed

The process of conversion of large multilamellar vesicles (MLVs) of dimyristoylphosphatidylcholine (DMPC) into the final state of small unilamellar vesicles (SUVs) with an increase in time length of ultrasonic irradiation was investigated by calorimetry and negative-stain electron microscopy. The process was found out to be composed of two stages depending on the primary (near 24 degrees C) and secondary (near 19 degrees C) peaks due to the gel-to-liquid crystal phase (Tm) transition, respectively; a new transition peak for the secondary Tm appears after a maximum broadening of the primary Tm peak is attained. Sonicated vesicles characterized by the primary peak of the broadest shape were observed to be about 200 nm in mean diameter and mostly four or so lamellae, and have an internal aqueous space, in contrast to sonicated SUVs (approx. 40 nm in diameter) characterized by the limiting secondary Tm peak. Thermal data associated with the Tm transition for these two sonicated vesicles were compared with that of the MLV. The enthalpy and entropy changes and cooperative units increased in the order sonicated SUV < sonicated large vesicle < MLV. Furthermore, the enthalpy changes were revealed to fairly differ between the sonicated large vesicle and SUV. Based on the effect of the annealing treatment at -5 degrees C on these vesicles the present result suggested a large contribution of the aggregation state of DMPC molecules to the enthalpy possessed by the vesicles of a gel phase temperature, which is related to the mode of the Tm transitions, primary and secondary. PMID:8334155

Kodama, M; Miyata, T; Takaichi, Y

1993-07-21

259

Calorimetric studies of the thermal denaturation of cytochrome c peroxidase  

SciTech Connect

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

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

1988-04-05

260

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

261

Calorimetric analysis of cryopreservation and freeze-drying formulations.  

PubMed

Differential scanning calorimetry (DSC) is a commonly used thermal analysis technique in cryopreservation and freeze-drying research. It has been used to investigate crystallization, eutectic formation, glass transition, devitrification, recrystallization, melting, polymorphism, molecular relaxation, phase separation, water transport, thermochemistry, and kinetics of complex reactions (e.g., protein denaturation). Such information can be used for the optimization of protective formulations and process protocols. This chapter gives an introduction to beginners who are less familiar with this technique. It covers the instrument and its basic principles, followed by a discussion of the methods as well as examples of specific applications. PMID:25428006

Sun, Wendell Q

2015-01-01

262

Thermal characterization of Li-ion cells using calorimetric techniques  

SciTech Connect

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

ROTH,EMANUEL P.

2000-05-31

263

Calorimetric efficiency measurements of supercapacitors and lithium-ion batteries  

Microsoft Academic Search

This paper presents efficiency measurements for a 125 V\\/63 F supercapacitor module (SC) and a 96 V\\/90 Ah lithium-ion (li-ion) battery system as a function of charge- discharge current frequency. The result would be useful in the design of efficient power flow control in systems using SCs and li-ion batteries as parallel energy storages, and offers a possibility to predict

Antti Virtanen; Hannu Haapala; Saara Hannikainen; Tuomas Muhonen; Heikki Tuusa

2011-01-01

264

Simulated performance of the calorimetric electron telescope (CALET) experiment  

NASA Astrophysics Data System (ADS)

CALET is a detector planned to be on-board the Japanese Experiment Module Exposed Facility (JEM-EF) of the International Space Station. The CALET mission aims at revealing unsolved problems in high energy phenomena of the Universe by carrying out a precise measurement of the high energy electrons in 1 GeV-20 TeV, the gamma-rays in 20 MeV to a few TeV and the nuclei in a few 10 GeV-1000 TeV. The main detector is composed of imaging calorimeter (IMC), total absorption calorimeter (TASC), silicon pixel array (SIA) and anti-coincidence detector (ACD) to detect various kinds of particles in very wide energy range. The total absorber thickness is 31 radiation lengths for electromagnetic particles and 1.4 interaction mean free paths for protons. Monte Carlo simulation study has been carried out for optimization of the detector performance in observing each kind of particles. We obtained following performance about the observation of very high energy (>100 GeV) electrons, which is a main target of the CALET experiment: (1) Effective geometrical factor is about 7000 cm2 sr. (2) Energy resolution is better than a few %. (3) Angular resolution is better than 0.1°. (4) Proton rejection power is ˜105 with the electron detection efficiency better than 95%. We also present the simulated performance of the CALET experiment in observing other particles.

Akaike, Y.; Taira, K.; Kasahara, K.; Torii, S.; Shimizu, Y.; Yoshida, K.; CALET Collaboration

2010-03-01

265

Simulated Performance of the CALorimetric Electron Telescope (CALET) experiment  

NASA Astrophysics Data System (ADS)

CALET is a detector planned to be on board the Japanese Experiment Module Exposed Facility(JEM-EF) of the International Space Station. The CALET mission aims at revealing unresolved problems in high energy phenomena of the Universe by carrying out a precise measurement of high energy gamma-rays in 20 MeV - TeV, electrons in 1 GeV - 20 TeV and hadronic cosmic rays in 10 GeV - 1000 TeV. It is now in a phase A study of the JAXA program. Main detector is composed of an IMaging Calorimeter (IMC), a Total AbSorption Calorimeter (TASC), SIlicon Array (SIA) and Scintillator Anti-Coincidence System (SACS) to observe various kind of particles in very wide energy range. The total absorber thickness is 31 r.l. for electromagnetic particles and 1.6 m.f.p. for protons. Monte Carlo simulation study has being carried out for optimization of the detector performance in observing each kind of particles. We use the EPICS, Electron-Photon Induced Cascade Simulator in a detector, code in which dpmjet3 is adopted as nuclear interaction model. We obtained following performance about the observation of very high energy (< 100 GeV) electrons, which is a main target of the CALET experiment: 1) Proton contamination in the observed electrons is less than 2 % without serious electron loss. 2) Energy resolution is better than a few %. 3) Angular resolution is better than 1 deg. 4) Effective geometrical factor is about 7000 cm2 sr. We will also present the simulated performance of the CALET experiment in observing other particles.

Akaike, Yosui; Kasahara, Katsuaki; Torii, Shoji; Shimizu, Yuki; Taira, Koichi; Yoshida, Kenji

266

Potentiometric determination of the gibbs energies of formation of SrZrO3 and BaZrO3  

NASA Astrophysics Data System (ADS)

The Gibbs free energies of formation of strontium and barium zirconates have been determined in the temperature range 960 to 1210 K using electrochemical cells incorporating the respective alkaline-earth fluoride single crystals as solid electrolytes. Pure strontium and barium monoxides were used in the reference electrodes. During measurements on barium zirconate, the oxygen partial pressure in the gas phase over the electrodes was maintained at a low value of 18.7 Pa to minimize the solubility of barium peroxide in the monoxide phase. Strontium zirconate was found to undergo a phase transition from orthorhombic perovskite (o) with space group Cmcm; D{2h/17} to tetragonal perovskite (t) having the space group 14/ mcm; D {4h/18} at 1123 (/+- 10) K. Barium zirconate does not appear to undergo a phase transition in the temperature range of measurement. It has the cubic perovskite (c) structure. The standard free energies of formation of the zirconates from their component binary oxides AO ( A = Sr, Ba) with rock salt (rs) and ZrO2 with monoclinic (m) structures can be expressed by the following relations: SrO (rs) + ZrO2 (m) ? SrZrO3 (o) ? G° = -74,880 - 14.2 T (/+-200) J mol-1 SrO (rs) + ZrO2 (m) ? SrZrO3 (t) ? G° = -73,645 - 15.37 T (/+-200) J mol-1 BaO (rs) + ZrO2 (m) ? BaZrO4 (c) ? G° = -127,760-1.79 T (/+-250) J mol-1 The results of this study are in reasonable agreement with calorimetric measurements reported in the literature. Systematic trends in the stability of alkaline-earth zirconates having the stoichiometry AZrO3 are discussed.

Jacob, K. T.; Waseda, Y.

1995-08-01

267

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

268

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

269

Determining Haugh Units  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

270

Determining Plausible Forecast Outcomes  

NSDL National Science Digital Library

The content of this lesson will assist the forecaster with the third step of the forecast process, namely, determining plausible forecast outcomes forward in time. The lesson will highlight the role of probabilistic forecast tools to assess the degree of uncertainty in a forecast, as well as suggest an approach for evaluating past and present model performance.

COMET

2010-08-17

271

Determination of Fat Content  

NASA Astrophysics Data System (ADS)

The term "lipid" refers to a group of compounds that are sparingly soluble in water, but show variable solubility in a number of organic solvents (e.g., ethyl ether, petroleum ether, acetone, ethanol, methanol, benzene). The lipid content of a food determined by extraction with one solvent may be quite different from the lipid content as determined with another solvent of different polarity. Fat content is determined often by solvent extraction methods (e.g., Soxhlet, Goldfish, Mojonnier), but it also can be determined by nonsolvent wet extraction methods (e.g., Babcock, Gerber), and by instrumental methods that rely on the physical and chemical properties of lipids (e.g., infrared, density, X-ray absorption). The method of choice depends on a variety of factors, including the nature of the sample (e.g., dry versus moist), the purpose of the analysis (e.g., official nutrition labeling or rapid quality control), and instrumentation available (e.g., Babcock uses simple glassware and equipment; infrared requires an expensive instrument).

Carpenter, Charles

272

What Determines Leadership Style?  

Microsoft Academic Search

This project examines selected traits valued in friends by educated individuals, and it seeks to determine if these valued traits vary by gender, race, and generational cohort. A literature review reveals that variations in leadership attributes are evident among these traits. In order to test the broad applicability of this literature, data were taken from the General Social Survey (GSS).

Apryl Silva

2009-01-01

273

COLORIMETRIC DETERMINATION OF MANGANESE  

E-print Network

colored MnO4- ion, and then determining the percentage of light absorbed by the MnO4 - for a set of reproducible conditions such as degree of dilution, wave length, and light path length. The problems associated with each of these factors are discussed below. Light Absorption When a chemical species absorbs visible

Bertsch George F.

274

Radio determination satellite service  

NASA Astrophysics Data System (ADS)

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

Briskman, Robert D.

1990-07-01

275

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

276

Determinants of Government Efficiency  

Microsoft Academic Search

Summary We compile the first large cross-country panel dataset of public sector performance and efficiency, encompassing 114 countries on all income levels from 1980 to 2004, with about 1,800 country-year observations for the education sector and about 900 observations for health. We regress these indicators on potential economic, institutional, demographic, and geographic determinants. Our most resounding conclusion is that higher

David Hauner; Annette Kyobe

2010-01-01

277

Microcalorimetric and SAXS Determination of PEO-SDS Interactions: The Effect of Cosolutes Formed by Ions  

E-print Network

The effect of different ionic cosolutes (NaCl, Na$_2$SO$_4$, Li$_2$SO$_4$, NaSCN, Na$_2$[Fe(CN)5NO], and Na$_3$[Co(NO)$_6$]) on the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene oxide) (PEO) was examined by small-angle X-ray scattering (SAXS) and isothermal titration calorimetric techniques. The critical aggregation concentration values (cac), the saturation concentration ($C_2$), the integral enthalpy change for aggregate formation ($\\Delta H_{\\mbox{agg}}$(int)) and the standard free energy change of micelle adsorption on the macromolecule chain ( $\\Delta\\Delta G_{\\mbox{agg}}$) were derived from the calorimetric titration curves. In the presence of 1.00 mmol L$^{-1}$ cosolute, no changes in the parameters were observed when compared with those obtained for SDS-PEO interactions in pure water. For NaCl, Na$_2$SO$_4$, Li$_2$SO$_4$, and NaSCN at 10.0 and 100 mmol L$^{-1}$, the cosolute presence lowered cac, increased $C_2$, and the PEO-SDS aggregate became more stable. In the presence of Na$_2$[Fe(CN)5NO], the calorimetric titration curves changed drastically, showing a possible reduction in the PEO-SDS degree of interaction, possibility disrupting the formed nanostructure; however, the SAXS data confirmed, independent of the small energy observed, the presence of aggregates adsorbed on the polymer chain.

Aparecida Mageste Barbosa; Igor José Boggione Santos; Guilherme Max Dias Ferreira; Maria do Carmo Hespanhol da Silva; Alvaro Vianna Novaes de Carvalho Teixeira; Luis Henrique Mendes da Silva

2014-08-30

278

Determination of the Structure and Catalytic Mechanism of Sorghum bicolor Caffeic Acid O-Methyltransferase and the Structural Impact of Three brown midrib12 Mutations.  

PubMed

Using S-adenosyl-methionine as the methyl donor, caffeic acid O-methyltransferase from sorghum (Sorghum bicolor; SbCOMT) methylates the 5-hydroxyl group of its preferred substrate, 5-hydroxyconiferaldehyde. In order to determine the mechanism of SbCOMT and understand the observed reduction in the lignin syringyl-to-guaiacyl ratio of three brown midrib12 mutants that carry COMT gene missense mutations, we determined the apo-form and S-adenosyl-methionine binary complex SbCOMT crystal structures and established the ternary complex structure with 5-hydroxyconiferaldehyde by molecular modeling. These structures revealed many features shared with monocot ryegrass (Lolium perenne) and dicot alfalfa (Medicago sativa) COMTs. SbCOMT steady-state kinetic and calorimetric data suggest a random bi-bi mechanism. Based on our structural, kinetic, and thermodynamic results, we propose that the observed reactivity hierarchy among 4,5-dihydroxy-3-methoxycinnamyl (and 3,4-dihydroxycinnamyl) aldehyde, alcohol, and acid substrates arises from the ability of the aldehyde to stabilize the anionic intermediate that results from deprotonation of the 5-hydroxyl group by histidine-267. Additionally, despite the presence of other phenylpropanoid substrates in vivo, sinapaldehyde is the preferential product, as demonstrated by its low Km for 5-hydroxyconiferaldehyde. Unlike its acid and alcohol substrates, the aldehydes exhibit product inhibition, and we propose that this is due to nonproductive binding of the S-cis-form of the aldehydes inhibiting productive binding of the S-trans-form. The S-cis-aldehydes most likely act only as inhibitors, because the high rotational energy barrier around the 2-propenyl bond prevents S-trans-conversion, unlike alcohol substrates, whose low 2-propenyl bond rotational energy barrier enables rapid S-cis/S-trans-interconversion. PMID:24948836

Green, Abigail R; Lewis, Kevin M; Barr, John T; Jones, Jeffrey P; Lu, Fachuang; Ralph, John; Vermerris, Wilfred; Sattler, Scott E; Kang, ChulHee

2014-06-19

279

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

280

Image based range determination  

NASA Technical Reports Server (NTRS)

Flight vehicles operating at low altitudes such as rotorcraft require range determination schemes for locating the terrain and obstacles. The development of a ranging scheme combining image sequences from vehicle mounted passive imaging sensors and the vehicle motion variables obtained from an on-board inertial navigation system is described. This approach can handle sequences from more than one imaging device. Derivation of the numerical algorithm and the performance results using a laboratory image sequence are given. Other applications of the proposed approach include ranging schemes for autonomous planetary rovers and telerobots.

Menon, P. K. A.; Sridhar, B.

1990-01-01

281

Determining Pregnancy in Cattle.  

E-print Network

jifferenc DETERMINING PREGNANCY IN CATTLE A. M. Sorensen, J r and J. R. Beverly* Economic returns from the beef cattle industry depend largely on the percent calf crop and the weaning weight of calves to be sold. Much has been done in the area... pregnant cows should be culled on the basis of age and condition of the udder, feet, legs and teeth which make them poor breeding stock. The following discussioh describes a way of improv- ing the calf crop percentage through pregnancy de- termination...

Sorensen, A. M. Jr.; Beverly, J. R.

1968-01-01

282

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

USGS Publications Warehouse

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

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

2003-01-01

283

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,

284

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

285

Satellite orbit determination  

NASA Technical Reports Server (NTRS)

A historic account of the activities of the Satellite OD Group during the MM'71 mission is given along with an assessment of the accuracy of the determined orbit of the Mariner 9 spacecraft. Preflight study results are reviewed, and the major error sources described. Tracking and data fitting strategy actually used in the real time operations is itemized, and Deep Space Network data available for orbit fitting during the mission and the auxiliary information used by the navigation team are described. A detailed orbit fitting history of the first four revolutions of the satellite orbit of Mariner 9 is presented, with emphasis on the convergence problems and the delivered solution for the first orbit trim maneuver. Also included are a solution accuracy summary, the history of the spacecraft orbit osculating elements, the results of verifying the radio solutions with TV imaging data, and a summary of the normal points generated for the relativity experiment.

Jordan, J. F.; Boggs, D. H.; Born, G. H.; Christensen, E. J.; Ferrari, A. J.; Green, D. W.; Hylkema, R. K.; Mohan, S. N.; Reinbold, S. J.; Sievers, G. L.

1973-01-01

286

On initial orbit determination  

NASA Technical Reports Server (NTRS)

The classical methods of initial orbit determination are brought together within a larger viewpoint. This new synthesis stresses that all such techniques follow one of three approaches. Either they seek to compute the orbital element set, or its equivalent, by attacking the differential equations of motion (Laplace), the first integrals of the equations of motion (Taff), or the solution itself (Gauss). The particular technique pursued within a given type of approach should depend upon the nature of the observational data, the amount of a priori information one is willing to presume, and the object of the exercise. This might be a binary star system, a moon, a minor planet, or an artificial satellite. The efficacy of some algorithms for each approach is discussed briefly. Unfortunately, none of them work very well. Extensions of these techniques to radars or laser radars are trivial and have provided no new insights into the overall problem.

Taff, L. G.

1984-01-01

287

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. PMID:22244230

Masilamani, Madhan; Commins, Scott; Shreffler, Wayne

2012-01-01

288

Tracer for circulation determinations  

SciTech Connect

An improved tracer particle is described comprising an ion exchange core having a polymer coating thereon, the coated ion exchange core having a reaction site capable of reacting with a compound containing an oxirane group, said coated ion exchange core having been treated with a compound containing an oxirane group to react with said coated ion exchange core causing an increase in mass of the tracer particle. Preferably, the ion exchange core is labelled with a radionuclide. These particles have improved characteristics including improved stability against leaching and improved handling properties. Such particles are useful in circulatory determinations involving the injection of the particles as a suspension in a physiologically acceptable carrier or medium into the circulatory system of animals.

Moore, H.; Santos, S.; Wysong, R. D.

1985-03-19

289

Ultratrace determination of curium  

SciTech Connect

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

Beitz, J.V.

1995-02-01

290

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

291

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

292

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

293

Effect of the composition of film-forming solutions and the temperature and time regimes on the colorimetric characteristics of film coatings  

SciTech Connect

The calorimetric characteristics of film coatings obtained from iron-containing industrial waste are determined by instrumental methods. The relationship between the composition of the film-forming solution, the temperature and time regimes of treatment and the calorimetric characteristics of film coatings such as lightness, brightness, and intensity (purity) of hue is described.

Sytnik, R.D.; Kiuila, I.G.; Ignatyuk, O.A. [Kharkov State Polytechnical Univ., Kharkov (Ukraine)

1995-11-01

294

Direct determination of the enthalpy of formation of MoB in synthesis from simple substances in an SHS system  

NASA Astrophysics Data System (ADS)

In a calorimetric bomb equipped with an electric microfurnace for heating a sample, self-propagating high-temperature synthesis (SHS) of molybdenum boride is realized in accordance with the reaction Mo (c) +B (amorph.)=MoB (c); the enthalpy of this reaction is measured, and the standard enthalpy of formation of molybdenum boride from metal molybdenum and crystaline boron is calculated: ?f H 0 (MoB,c,?,?)=103.9?1.2kJ/mole.

Lavut, E. G.; Chelovskaya, N. V.; Kashireninov, O. E.

1993-10-01

295

Determining a Soil's Textural Classification  

NSDL National Science Digital Library

In this activity students use screen sieves to determine the percent of sand, silt, and clay in a soil sample. They then use a tertiary soil diagram to determine the generic soil name of their sample. Students will learn to use particle size analysis as a tool to determine a soil's texture and understand the role of sand, silt, and clay sized particles in a soil. The site has a link to obtain the required soil diagram.

296

On a class of determinants  

E-print Network

A class of determinants is introduced. Different kind of mathematical objects, such as Fibonacci, Lucas, Tchebychev, Hermite, Laguerre, Legendre polynomials, sums and covergents are represented as determinants from this class. A closed formula in which arbitrary term of a homogenous linear recurrence equation is expressed in terms of the initial conditions and the coefficients is proved.

Janjic, Milan

2009-01-01

297

Mouse Genetics: Determining gene function  

E-print Network

Mouse Genetics: Determining gene function An International Centre for Mouse Genetics Mammalian Genetics Unit #12;Determining gene function · Mutagenesis approaches · Gene-driven, phenotype for Mouse Genetics Mammalian Genetics Unit #12;An International Centre for Mouse Genetics Mammalian Genetics

Goldschmidt, Christina

298

Self-Determination. Feature Issue.  

ERIC Educational Resources Information Center

This theme issue explores the relevance of self-determination for persons with developmental disabilities across the life span, ways in which it is or can be expressed, and obstacles to its exercise. The articles show the futility of enhancing self-determination by teaching choice-making skills if environments offer no opportunities to exercise…

IMPACT, 1994

1994-01-01

299

Interactions of water with roasted and ground coffee in the wetting process investigated by a combination of physical determinations.  

PubMed

Three complementary techniques were used in this study to investigate the physical changes during wetting of roasted and ground coffee. Scanning electron microscopy (SEM) was found to provide indirect evidence of the presence of liquid water in the coffee particles. The effect of wetting on coffee closed porosity was studied by helium pycnometry, and finally, particle sizing was used to determine the swelling kinetics of coffee after wetting. Due to the solubilization of compounds, the presence of liquid water could be detected in the coffee cells by SEM. The technique was then used to investigate different water contents; for example, for roasted and ground coffee containing 1 g of water per gram of coffee on a dry basis, liquid water was present in cells only at the periphery of approximately 1.0 mm diameter particles. Coffee closed porosity decreased with increasing water content, as evidenced by pycnometry. For roasted and ground coffee containing 1 g of water per gram of coffee, results showed a closed porosity lower that 0.1 cm3/g ( approximately 20% of the closed porosity measured in dry particles). The decrease of closed porosity may be attributed to both (1) water filling cells' lumen and (2) plasticization of cell wall polymers, resulting in the matrix relaxation and increase of helium accessibility to the pores. Water binding to the matrix polymers was further investigated by calorimetric measurements. The integration of the endothermic peak of freezing water showed that approximately 0.15 g of water/g of coffee is nonfreezable water, that is, water bound to the matrix polymers. Finally, the use of particle sizing showed that the average volume of the coffee particles with 1 g of water/g of coffee increased by up to 20-23% at 10-15 min following wetting. Moisture diffusion coefficients in coffee particles [( approximately 2-3) x 10(-11) m2 s(-1)] were approximated by fitting the swelling curves with a model of diffusion. The observed results may give information about homogeneity and the physical state of water in wetted roasted coffee and thus increase the understanding of the mechanisms of molecular mass transfer during extraction. PMID:17373809

Mateus, Maria-L; Rouvet, Martine; Gumy, Jean-C; Liardon, Rémy

2007-04-18

300

Evans function and Fredholm determinants  

PubMed Central

We explore the relationship between the Evans function, transmission coefficient and Fredholm determinant for systems of first-order linear differential operators on the real line. The applications we have in mind include linear stability problems associated with travelling wave solutions to nonlinear partial differential equations, for example reaction–diffusion or solitary wave equations. The Evans function and transmission coefficient, which are both finite determinants, are natural tools for both analytic and numerical determination of eigenvalues of such linear operators. However, inverting the eigenvalue problem by the free-state operator generates a natural linear integral eigenvalue problem whose solvability is determined through the corresponding infinite Fredholm determinant. The relationship between all three determinants has received a lot of recent attention. We focus on the case when the underlying Fredholm operator is a trace class perturbation of the identity. Our new results include (i) clarification of the sense in which the Evans function and transmission coefficient are equivalent and (ii) proof of the equivalence of the transmission coefficient and Fredholm determinant, in particular in the case of distinct far fields. PMID:25663806

Karambal, Issa; Malham, Simon J. A.

2015-01-01

301

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

302

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

303

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

304

Determining Cropland Share Rental Arrangements  

E-print Network

Determining Cropland Share Rental Arrangements Kevin C. Dhuyvetter, Terry L. Kastens and Joe L. Outlaw * Many crop producers rely heavily on rented land in their farming operations. The rental arrangements between landowners and producers can...

Dhuyvetter, Kevin C.; Kastens, Terry L.; Outlaw, Joe

1999-06-23

305

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

306

Cotton Gin Dust Explosibility Determinations  

E-print Network

Following the recent Imperial sugar dust explosion in 2008, a comprehensive survey of past dust explosions was conducted by the Occupational Safety and Health Administration (OSHA) to determine potential explosible dusts. After the survey, OSHA...

Vanderlick, Francis Jerome

2014-01-06

307

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.

308

Polarographic determination of extraction constants.  

PubMed

The extraction constant of three organic compounds containing nitrogen as a picrate ion pair in a water-chloroform system were determined by following polarographically the picrate concentration in the aqueous phase as a function of the added amount of reagent. The extraction constants were also determined spectrophotometrically (via batch extraction). The obtained results are in good agreement. The proposed method is applicable for extraction constants with values between 10(3) and 10(9). PMID:3658646

Dingjan, H A; Van Bennekom, W P; Bult, A

1987-08-21

309

Spectrophotometric determination of some dithiocarbamates.  

PubMed

A procedure has been developed for the determination of six dithiocarbamates [sodium dimethyldithiocarbamate (dibam), sodium diethyldithiocarbamate (NaDDC), tetramethylthiuram disulphide (thiram), zinc dimethyldithiocarbamate (ziram), sodium N-methylpiperazinecarbodithioate and potassium morpholine-4-carbodithioate] in microgram quantities by converting them into selenium dithiocarbamate complexes, which are then extracted into chloroform and measured at 430 nm against a reagent blank. The method is sensitive and can be used for the determination of dithiocarbamates in commercial samples and synthetic mixtures. PMID:18965097

Malik, A K; Rao, A L

1990-12-01

310

Sex determination mechanisms in fish  

Microsoft Academic Search

In fish, sex determination (SD) system shows high variation. The SD mechanisms include environmental and genetic regulation.\\u000a The research on SD system and related genes in intensively studied fish species was reviewed. Although some genes have been\\u000a described as sex-related, only DMRT1bY can be considered as a master sex determination gene and none of them has been utilized in aquaculture.

Quanqi Zhang; Xiaohua Sun; Jie Qi; Zhigang Wang; Xinglian Wang; Xubo Wang; Teng Zhai

2009-01-01

311

Gender determination of avian embryo  

DOEpatents

Disclosed is a method for gender determination of avian embryos. During the embryo incubation process, the outer hard shells of eggs are drilled and samples of allantoic fluid are removed. The allantoic fluids are directly introduced into an ion mobility spectrometer (IMS) for analysis. The resulting spectra contain the relevant marker peaks in the positive or negative mode which correlate with unique mobilities which are sex-specific. This way, the gender of the embryo can be determined.

Daum, Keith A. (Idaho Falls, ID); Atkinson, David A. (Idaho Falls, ID)

2002-01-01

312

Mass Determinations of Star Clusters  

E-print Network

Mass determinations are difficult to obtain and still frequently characterised by deceptively large uncertainties. We review below the various mass estimators used for star clusters of all ages and luminosities. We highlight a few recent results related to (i) very massive old star clusters, (ii) the differences and similarities between star clusters and cores of dwarf elliptical galaxies, and (iii) the possible strong biases on mass determination induced by tidal effects.

Georges Meylan

2001-07-03

313

Genetic determinants of human hypertension.  

PubMed Central

Hypertension is a common trait of multifactorial determination imparting an increased risk of myocardial infarction, stroke, and end-stage renal disease. The primary determinants of hypertension, as well as the factors which determine specific morbid sequelae, remain unknown in the vast majority of subjects. Knowledge that a large fraction of the interindividual variation in this trait is genetically determined motivates the application of genetic approaches to the identification of these primary determinants. Success in this effort will afford insights into pathophysiology, permit preclinical identification of subjects with specific inherited susceptibility, and provide opportunities to tailor therapy to specific underlying abnormalities. To date, mutations in three genes have been implicated in the pathogenesis of human hypertension: mutations resulting in ectopic expression of aldosterone synthase enzymatic activity cause a mendelian form of hypertension known as glucocorticoid-remediable aldosteronism; mutations in the beta subunit of the amiloride-sensitive epithelial sodium channel cause constitutive activation of this channel and the mendelian form of hypertension known as Liddle syndrome; finally, common variants at the angiotensinogen locus have been implicated in the pathogenesis of essential hypertension in Caucasian subjects, although the nature of the functional variants and their mechanism of action remain uncertain. These early findings demonstrate the feasibility and utility of the application of genetic analysis to dissection of this trait. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7567973

Lifton, R P

1995-01-01

314

Spherical Dirac GJMS operator determinants  

NASA Astrophysics Data System (ADS)

Motivated by AdS/CFT, the extension is made to spin-half of a scalar calculation of the conformal anomalies and functional determinants of GJMS operators on spheres. The formal aspects are heuristic but sufficient. A Barnes zeta-function representation again proves effective. The determinants are calculated for the two factorizations of the general ?-function (intertwiner) form of the GJMS operator, and shown to be equal, even including any multiplicative anomaly. A comment is made on the general eigenvalue problem and a few numerical results are presented. An alternative approach is detailed for odd dimensions and it is shown that the scalar determinants are expressed in terms of the spinor ones, and vice versa. An explicit, general form is given.

Dowker, J. S.

2015-01-01

315

A process for determining radiohalogens  

SciTech Connect

Techniques for the separation and potential determination of chlorine-36 and iodine-129 were examined. Separation was based upon addition to the carbon-carbon double bond in 1-hexene. These specific organic halides formed an acceptable liquid scintillation counting cocktail with chlorine but not with iodine. The miscibility of 1,2-dichlorohexane should allow a larger mass of sample in a scintillation cocktail, lowering the detection limit of the determination of chlorine-36. Organic halides are also expected to be more receptive to waste treatment than metals such as silver. These techniques offer the potential for determination of chlorine-36 in groundwater samples while producing less mixed waste than current analytical techniques.

Washington, W.J.; Hohorst, F.A.

1993-12-01

316

Determination of radium in water  

USGS Publications Warehouse

Radium isotopes are common radioactive constituents of natural waters. The concentration of radium-226 in potable water is of particular significance because this isotope is generally considered the most hazardous of all radionuclides with respect to ingestion. The approximate concentration of radium-226 is determined after coprecipitating radium with barium sulfate. The short-lived daughters of radium are allowed to grow for 10-12 days, then the alpha activity of the precipitate is measured and compared with that of a precipitate containing a known amount of radium-226. Concentrations of the individual alpha-emitting isotopes of radium-223, radium-224, and radium-226, are determined by coprecipitating radium first with lead sulfate, then with barium chloride, and finally with barium sulfate. This final precipitate is initially free of other alpha-emitting nuclides, thus permitting the isotopic composition to be determined by measuring the growth and decay of the alpha activity of the precipitate.

Barker, Franklin Butt; Johnson, J.O.

1964-01-01

317

Decoherence, determinism and chaos revisited  

NASA Astrophysics Data System (ADS)

We suggest that the derivation of the free space Maxwell Equations for classical electromagnetism, using a discrete ordered calculus developed by L.H. Kauffman and T. Etter, necessarily pushes the discussion of determinism in natural science down to the level of relativistic quantum mechanics and hence renders the mathematical phenomena studied in deterministic chaos research irrelevant to the question of whether the world investigated by physics is deterministic. We believe that this argument reinforces Suppes' contention that the issue of determinism versus indeterminism should be viewed as a Kantian antinomy incapable of investigation using currently available scientific tools.

Noyes, H. P.

318

Determining Readability with a Microcomputer.  

ERIC Educational Resources Information Center

Discusses history of the development of computer software to determine material readability and general design of readability software. Tables present summaries of: (1) parameters used by selected readability scales and their grade level applications; and (2) microcomputer software programs available, including readability techniques included in…

Kennedy, Keith

1985-01-01

319

Determining Salinity by Simple Means.  

ERIC Educational Resources Information Center

This paper describes the construction and use of a simple salinometer. The salinometer is composed, mainly, of a milliammeter and a battery and uses the measurement of current flow to determine the salinity of water. A complete list of materials is given, as are details of construction and operation of the equipment. The use of the salinometer in…

Schlenker, Richard M.

320

Calculator programs determine drilling hydraulics  

Microsoft Academic Search

Two TI-59 programs were prepared for the calculation of drilling hydraulics as set forth in the Hughes Tool Co. publication, Practical Hydraulics. One presents the stepwise determination of drill string pressure drop while the second, to be published in a future issue, calculates jet area, jet velocity and impact force along with bit pressure drop and hydraulic horsepower. Another section

Landry

1987-01-01

321

Self-Determination and Bilingualism  

ERIC Educational Resources Information Center

This article focuses on additive bilingualism for minority group children, more specifically the development of strong literacy skills in English and in the children's language. The personal autonomization language learning (PALL) model is presented. It specifies eight testable hypotheses. Self-determination theory (SDT) is central in the PALL…

Landry, Rodrigue; Allard, Real; Deveau, Kenneth

2009-01-01

322

The Determinants of Cardiac Output  

NSDL National Science Digital Library

Part of the Gross Physiology of the Cardiovascular System site, this 22-minute video presentation explains fundamental but often misunderstood concepts about the determinants of cardiac output, using Dr. Anderson's hydraulic model of the cardiovascular system. It is a useful summary and overview of the concepts presented in greater detail in the online text. A transcript of the video presentation is available.

Anderson, Robert M.

323

Determining Cropland Cash Rental Arrangements  

E-print Network

Determining Cropland Cash Rental Arrangements Kevin C. Dhuyvetter, Terry L. Kastens and Joe L. Outlaw* Many crop producers rely heavily on rented land in their farming operations. Crop land is typically rented in one of three ways: (1) cash rent; (2...

Dhuyvetter, Kevin C.; Kastens, Terry L.; Outlaw, Joe

1999-06-23

324

Determinants of Default Probability Changes?  

Microsoft Academic Search

This paper investigates some common determinants of default probability changes of individual flrms using Standard & Poor's ratings database. We analyze and quantify the re- sponses of hazard rates to changes in various economic variables, namely flnancial markets, business cycle and credit indicators, and examine their persistency. First, we show that in- cluding non-flnancial information largely improves the poor explanatory

F. Couderc

325

Determinants and Polynomial Root Structure  

ERIC Educational Resources Information Center

A little known property of determinants is developed in a manner accessible to beginning undergraduates in linear algebra. Using the language of matrix theory, a classical result by Sylvester that describes when two polynomials have a common root is recaptured. Among results concerning the structure of polynomial roots, polynomials with pairs of…

De Pillis, L. G.

2005-01-01

326

National Mining Association Experimental Determination  

E-print Network

Charcoal Canisters (LAACCs) Concluded that radon fluxes obeyed the Stagnant Film Model (SFM) and that flux with the dissolved Radium-226. A picture of the floating Large Area Activated Charcoal Canister (LAACC) used of determining Radon ­ 222 flux, specifically using Large Area Activated Charcoal Canisters (LAACCs) as described

327

Self-Determination: First Steps.  

ERIC Educational Resources Information Center

The year 1974 marked the first full year in which the Bureau of Indian Affairs (BIA) officially embarked on a policy of advising and assisting American Indian tribes to assume the administration of their own affairs (self-determination). It seeks to strengthen and stabilize tribal governments while continuing to maintain and fulfill its trust…

Thompson, Morris

328

Factors determining desert dune type  

Microsoft Academic Search

While most observers recognize four elemental types of desert dunes (longitudinal, transverse, barchan and star1-3) there is little agreement about which factors determine these types. The angular relationships between the resultant of sand shifting winds and both the crest and principal slipfaces of the elemental types have been discussed qualitatively for many decades. These relationships have been quantified but the

R. J. Wasson; R. Hyde

1983-01-01

329

GEET DUGGAL Algorithms for Determining  

E-print Network

experiments allow us to observe regions of DNA that are spatially close to each other in the nucleus of cellsGEET DUGGAL Algorithms for Determining the Higher Order Three- Dimensional Structure of DNA and its. Analyses from them have shown that the 3D structure of DNA may be closely linked to genome functions

330

Performing Determinism: Disability Culture Poetry  

Microsoft Academic Search

“Performing Determinism” discusses the performance of disability through poetry: the instability of language, the ability of words to clasp both generic and specific meaning, and the gaps that surround the performances of self. Disability culture acts as a frame for the inquiry, as the essay discusses crip aesthetics, crip critical practice, and the embodiment of language. In the reading of

Petra Kuppers

2007-01-01

331

Determination of radium in water  

SciTech Connect

These detailed work instructions (DWIs) are tailored for the analysis of radium-226 and radium-228 in drinking water supplies from ground water and surface water sources and composites derived from them. The instructions have been adapted from several sources, including a draft EPA method. One objective was to minimize the generation of mixed wastes. Quantitative determinations of actinium-228 are made at 911 keV. The minimum detection level (MDL) for the gamma spectrometric measurements at this energy vary with matrix, volume, geometry, detector, background, and counting statistics. The range of MDL`s for current detectors is 0.07 to 0.5 Bq/sample. Quantitative determinations of radium-226 are made by counting the high energy alpha particles which radium-226 progeny emit using liquid scintillation counting (LSC). The minimum detectable activity (MDA) is 3.8 E-3 Bq/sample. The maximum concentration which may be counted on available instruments without dilution is about 2 E + 5 Bq/sample. Typically, this determination of radium in a 2 L sample has a yield of 80%. If radium-228 is determined using a 16 h count after 50 h grow-in, the typical MDL is 1 E-9 to 8 E-9 {mu}Ci/mL (1 to 8 pCi/L). If radium-226 is determined using a 2.5 h count after 150 h grow-in, the typical MDA is about 1 E-10 {mu}Ci/mL (0. 1 pCi/L).

Hohorst, F.A.; Huntley, M.W.; Hartenstein, S.D.

1995-10-01

332

43 CFR 11.81 - Damage determination phase-restoration and compensation determination plan.  

Code of Federal Regulations, 2012 CFR

... true Damage determination phase-restoration and compensation determination plan...81 Damage determination phase—restoration and compensation determination plan...The authorized official shall develop a Restoration and Compensation Determination...

2012-10-01

333

43 CFR 11.81 - Damage determination phase-restoration and compensation determination plan.  

...false Damage determination phase-restoration and compensation determination plan...81 Damage determination phase—restoration and compensation determination plan...The authorized official shall develop a Restoration and Compensation Determination...

2014-10-01

334

43 CFR 11.81 - Damage determination phase-restoration and compensation determination plan.  

Code of Federal Regulations, 2011 CFR

...false Damage determination phase-restoration and compensation determination plan...81 Damage determination phase—restoration and compensation determination plan...The authorized official shall develop a Restoration and Compensation Determination...

2011-10-01

335

43 CFR 11.81 - Damage determination phase-restoration and compensation determination plan.  

Code of Federal Regulations, 2010 CFR

...false Damage determination phase-restoration and compensation determination plan...81 Damage determination phase—restoration and compensation determination plan...The authorized official shall develop a Restoration and Compensation Determination...

2010-10-01

336

43 CFR 11.81 - Damage determination phase-restoration and compensation determination plan.  

Code of Federal Regulations, 2013 CFR

...false Damage determination phase-restoration and compensation determination plan...81 Damage determination phase—restoration and compensation determination plan...The authorized official shall develop a Restoration and Compensation Determination...

2013-10-01

337

Situational determinants of fish consumption  

Microsoft Academic Search

Despite having properties well-suited to “healthy-eating”, fish is a declining product. Consumers’ evaluations of fish are known to differ between consumers and non-consumers, but the precise differences, which might be of use in the development of a marketing campaign, are vague. Analyses suggest that the factors that influence consumer choice are predominantly environmental, and a model of situational determinants of

Sheena Leek; Sarah Maddock; Gordon Foxall

2000-01-01

338

Method for determining gene knockouts  

DOEpatents

A method for determining candidates for gene deletions and additions using a model of a metabolic network associated with an organism, the model includes a plurality of metabolic reactions defining metabolite relationships, the method includes selecting a bioengineering objective for the organism, selecting at least one cellular objective, forming an optimization problem that couples the at least one cellular objective with the bioengineering objective, and solving the optimization problem to yield at least one candidate.

Maranas, Costa D; Burgard, Anthony R; Pharkya, Priti

2013-06-04

339

Method for determining gene knockouts  

DOEpatents

A method for determining candidates for gene deletions and additions using a model of a metabolic network associated with an organism, the model includes a plurality of metabolic reactions defining metabolite relationships, the method includes selecting a bioengineering objective for the organism, selecting at least one cellular objective, forming an optimization problem that couples the at least one cellular objective with the bioengineering objective, and solving the optimization problem to yield at least one candidate.

Maranas, Costas D. (Port Matilda, PA); Burgard, Anthony R. (State College, PA); Pharkya, Priti (State College, PA)

2011-09-27

340

Range determination for scannerless imaging  

DOEpatents

A new method of operating a scannerless range imaging system (e.g., a scannerless laser radar) has been developed. This method is designed to compensate for nonlinear effects which appear in many real-world components. The system operates by determining the phase shift of the laser modulation, which is a physical quantity related physically to the path length between the laser source and the detector, for each pixel of an image.

Muguira, Maritza Rosa (Albuquerque, NM); Sackos, John Theodore (Albuquerque, NM); Bradley, Bart Davis (Albuquerque, NM); Nellums, Robert (Albuquerque, NM)

2000-01-01

341

In-flight thrust determination  

NASA Technical Reports Server (NTRS)

The major aspects of processes that may be used for the determination of in-flight thrust are reviewed. Basic definitions are presented as well as analytical and ground-test methods for gathering data and calculating the thrust of the propulsion system during the flight development program of the aircraft. Test analysis examples include a single-exhaust turbofan, an intermediate-cowl turbofan, and a mixed-flow afterburning turbofan.

Abernethy, Robert B.; Adams, Gary R.; Ascough, John C.; Baer-Riedhart, Jennifer L.; Balkcom, George H.; Biesiadny, Thomas

1986-01-01

342

Colorimetric determination of indolic drugs.  

PubMed

A colorimetric method has been developed for the quantitative determination of the rescinnamine, reserpine upto (-10(-4M)), Yohimbine on complexation with bromothymol blue. The coloured complexes exhibit absorption maxima in the region 415-416 nm. The RSD (Relative Standard Deviation) of the method is 2.02%. The method is simple, easy, rapid and convenient for routine analysis of the indolic drugs. PMID:16431399

Azhar, Iqbal; Mazhar, Farah; Manzar, Qazi Nawab; Hussain, Iftekhar; Shamim, Sumbul

2005-04-01

343

Geostar Radio Determination Satellite System  

NASA Astrophysics Data System (ADS)

The Geostar Radio Determination Satellite System is designed to provide accurate position information and ancillary message passing capability for land mobile, marine, and aeronautical users in the United States and eventually worldwide. The Geostar system is a random access spread spectrum system capable of high positioning accuracy. Geostar can support a large population of users operating inexpensive transceivers. This paper examines the Geostar system positioning technique, error sources, anticipated accuracy, and potential applications.

Richards, Robert T.

344

Determining Internal Connections in Capacitors  

NASA Technical Reports Server (NTRS)

Simple electrical test shows which terminals connected to outer capacitor foil. Test makes it unnecessary to resort to X-ray inspection to distinguish terminals. When outer foil of capacitor is attached to ungrounded signal-generator output lead, oscilloscope displays higher waveform amplitude. When outer foil is joined to grounded signalgenerator output lead, waveform amplitude is lower. Test also used to determine internal connections in multiple-element capacitors.

Ott, F. M.; Hanna, M. F.

1986-01-01

345

Experimental determination of plastic zones  

Microsoft Academic Search

We present four experimental series for the determination of the size and shape of plastic zones due to monotonic and cyclic\\u000a loadings. Specimens contain notches of various geometries but not cracks. This provides the possibility to study the effect\\u000a of notch radius and the repetitions of loading without the disturbing influence of crack closure and the previous loading\\u000a history. Different

E. Czoboly; B. Csizmazia; I. Havas

1996-01-01

346

Meteorological determinants of air quality  

NASA Astrophysics Data System (ADS)

Air quality is the result of complex phenomena, among which the major role is played by human emissions of pollutants. Atmospheric processes act as determinants, e.g., modulating, dumping or amplifying the effects of emissions as an orchestra's director does with musical instruments. In this work, a series of small-scale and meso-scale meteorological determinants of air-quality are presented as they are observed in an area characterized by complex orography (Friuli Venezia Giulia, in the north-eastern side of Italy). In particular, attention is devoted to: i) meso-scale flows favouring the persistence of high concentrations of particulate matter; ii) meso-scale periodic flows (breezes) favouring high values of particulate matter; iii) local-scale thermodynamic behaviour favouring high atmospheric values of nitrogen oxides. The effects of these different classes of determinants are shown through comparisons between anthropic emissions (mainly traffic) and ground-based measurements. The relevance of complex orography (relatively steep relieves near to the sea) is shown for the meso-scale flows and, in particular, for local-scale periodic flows, which favour the increase of high pollutants concentrations mainly in summer, when the breezes regime is particularly relevant. Part of these results have been achieved through the ETS - Alpine Space EU project iMONITRAF!

Turoldo, F.; Del Frate, S.; Gallai, I.; Giaiotti, D. B.; Montanari, F.; Stel, F.; Goi, D.

2010-09-01

347

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.

348

Proceedings SPIE, Ophthalmic Technologies XVI, SPIE vol. 6138 (2006) Plasma-Mediated Transfection of RPE  

E-print Network

methods (liposomes, sonoporation and electroporation) have either low efficiency in- vivo or produce the susceptibility of cellular membranes to electroporation. For synchronous application of electric field technique exceeded that of standard electroporation by a factor 10,000. Safe and effective non-viral DNA

Palanker, Daniel

349

SPIE Proceedings, Laser-Tissue Interactions XVI, vol. 5695, BIOS 2005 Cellular tolerance to pulsed heating  

E-print Network

of 0.3 ms to 5 seconds. Thin layer of cells cultured in a Petri dish was exposed to a pulsed CO2 laser s of heating to 160 o C at pulses of 0.3 ms in duration. The shorter end of this range was limited by vaporization, which occurs during the laser pulse and results in mechanical damage to cells. Dependence

Palanker, Daniel

350

XVI. Non-symbiotic nitrogen-fixing bacteria of two cultivated Soils  

Microsoft Academic Search

In Taupo and Cass soils under tussock grassland in New Zealand, the numbers of bacteria producing typical colonies of the nitrogen-fixing bacterium, Clostridium butyricum, were found to be similar in samples taken from the base of Festuca tussock plants and between well-spaced Festuca tussock plants. Total numbers of clostridia were a little higher in soil from the base of tussock

D. J. Ross

1960-01-01

351

Exito para el XVI Festival Internacional de Teatro Hispano del Teatro Avante  

E-print Network

una brillante producción de Cenizas sobre el mar del dramaturgo colombiano José Assad. La obra fue escrita entre 1988-9, estrenada en Bogotá en 1990 y presentada en el Teatro Colón de Miami Beach, la única del festival puesta fuera del Teatro... musicales de Mike Porcel, los cuales hicieron de esta producción evento sumamente dramático, en el mejor sentido de la palabra. No menos valiente fue la dirección predominantemente de Lilliam Vega, según la propia admisión de Mario Ernesto Sánchez. Esto...

Marrero, Marí a Teresa

2002-04-01

352

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

Federal Register 2010, 2011, 2012, 2013

...how a language disorder contributes to limited attention and problems on a job. 2. We may receive evidence from other medical sources...setting (for example, trips to the grocery store to develop math, sequencing, travel, and social skills)....

2011-09-12

353

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.

354

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. PMID:19669655

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

2009-01-01

355

i6e Anne (Tome XVI). Mars 1936. N 153 LE' LAITREVUE GNRALE DES QUESTIONS LAITIRES  

E-print Network

Mémoires originaux: TALCE-NIEDRA (Dagmara). - La catalase des bactéries d'acide lactique . . . . . 225 M . . .'. . .... 335 .Nécrologie, M. H�NNE- BERG. . 335 l\\f�l\\10IRES ORIGINAUX (1) LB LAIT, 1936 LA CATALASE DES Directeur Dr. A' KIRCHENSTEINS;, On se sert assez souvent de la réaction de la 'catalase pour déter- miner

Boyer, Edmond

356

Student Characteristics as Compared to the Community Profile, Fall, 1986. Volume XVI, No. 8.  

ERIC Educational Resources Information Center

In fall 1986, a study was conducted at Illinois' William Rainey Harper College (WRHC) to provide a student profile for general information purposes, to gather data not available on the college's automated student data file, and to analyze WRHC's market outreach. Surveys were mailed to random samples of 500 credit degree students and 300 continuing…

Flaherty, Toni

357

Student Characteristics as Compared to the Community Profile, Fall 1987. Volume XVI, No. 13.  

ERIC Educational Resources Information Center

In fall 1987, a study was conducted at William Rainey Harper College (WRHC) to develop a profile of WRHC students and assess the college's market outreach. Surveys were mailed to random samples of 500 degree credit students and 300 non-degree credit students. Response rates of 80% for the degree credit students and 78% for the non-degree credit…

Flaherty, Toni

358

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.

359

Intercultural Communication Studies XVI: 3 A Disease That "Has a Woman's Face": The Social Construction  

E-print Network

inequalities in socio-economic status and patriarchal ideology around sexual practices are one of the most important, yet often neglected reasons for the feminization of this disease. The social ideology surrounding patriarchal ideology and consciously produce empowering discourses to help women survive. HIV/AIDS represents

Kvasny, Lynette

360

Micro-Raman identification of the palette of a precious XVI century illuminated Persian codex  

Microsoft Academic Search

A remarkable, richly decorated Persian manuscript dating from 1537 was investigated by Raman microscopy in order to assess the nature of the pigments used. Although the decorated area measures just a few tens of cm2 and doesn’t include any anthropomorphic motif, but consists in a very geometric, lacework-like decoration, it contains very elaborate and precious details. A very rich palette

Silvia Bruni; Franco Cariati; Francesca Casadio; Vittoria Guglielmi

2001-01-01

361

20 CFR 416.1535 - Services in a proceeding under title XVI of the Act.  

Code of Federal Regulations, 2010 CFR

...Act. 416.1535 Section 416.1535 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Representation of Parties § 416.1535 Services in a proceeding under...

2010-04-01

362

36 CFR 223.36 - Volume determination.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Volume determination. 223.36 Section 223...Conditions and Provisions § 223.36 Volume determination. (a) Timber sale contracts may provide for volume determination by scaling,...

2013-07-01

363

36 CFR 223.36 - Volume determination.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Volume determination. 223.36 Section 223...Conditions and Provisions § 223.36 Volume determination. (a) Timber sale contracts may provide for volume determination by scaling,...

2012-07-01

364

36 CFR 223.36 - Volume determination.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Volume determination. 223.36 Section 223...Conditions and Provisions § 223.36 Volume determination. (a) Timber sale contracts may provide for volume determination by scaling,...

2011-07-01

365

36 CFR 223.36 - Volume determination.  

...2014-07-01 2014-07-01 false Volume determination. 223.36 Section 223...Conditions and Provisions § 223.36 Volume determination. (a) Timber sale contracts may provide for volume determination by scaling,...

2014-07-01

366

Calculator programs determine drilling hydraulics  

SciTech Connect

Two TI-59 programs were prepared for the calculation of drilling hydraulics as set forth in the Hughes Tool Co. publication, Practical Hydraulics. One presents the stepwise determination of drill string pressure drop while the second, to be published in a future issue, calculates jet area, jet velocity and impact force along with bit pressure drop and hydraulic horsepower. Another section of the second program considers pump mechanics, calculating the required strokes per minute to attain a specific circulating rate, or the circulation that would result from a specific pump speed. Hydraulic horsepower of the pump is then calculated from this rate and a maximum pump pressure.

Landry, W.E.

1987-05-01

367

Crystal face temperature determination means  

DOEpatents

An optically transparent furnace having a detection apparatus with a pedestal enclosed in an evacuated ampule for growing a crystal thereon is disclosed. Temperature differential is provided by a source heater, a base heater and a cold finger such that material migrates from a polycrystalline source material to grow the crystal. A quartz halogen lamp projects a collimated beam onto the crystal and a reflected beam is analyzed by a double monochromator and photomultiplier detection spectrometer and the detected peak position in the reflected energy spectrum of the reflected beam is interpreted to determine surface temperature of the crystal. 3 figs.

Nason, D.O.; Burger, A.

1994-11-22

368

COBE ground segment attitude determination  

NASA Technical Reports Server (NTRS)

The Cosmic Background Explorer (COBE) spacecraft was launched in November 1989 by NASA to survey the sky for primordial radiation left from the Big Bang explosion. The success of the mission requires an accurate determination of the spacecraft attitude. While the accuracy of the attitude obtained from the attitude sensors is adequate for two of the experiments, the higher accuracy required by the Diffuse Infrared Background Experiment (DIRBE) is obtained by using the DIRBE instrument as a special type of star sensor. Presented here is an overview of the attitude processing algorithms used at the Cosmology Data Analysis Center (CDAC) and the results obtained from the flight data.

Kumar, V. K.; Freedman, I.; Wright, E. L.; Patt, F. S.

1991-01-01

369

Determination of uranium in zircon  

USGS Publications Warehouse

A routine fluorimetric procedure is described for the determination of trace amounts of uranium in zircon. It employs the direct extraction of uranyl nitrate with ethyl acetate using phosphate as a retainer for zirconium. Submicrogram amounts or uranium are separated in the presence of 100,000 times the amount of zirconium. The modified procedure has been worked out using synthetic mixtures of known composition and zircon. Results of analyses have an accuracy of 97-98% of the contained uranium and a standard deviation of less than 2.5%. ?? 1959.

Cuttitta, F.; Daniels, G.J.

1959-01-01

370

Liquid chromatographic determination of water  

DOEpatents

A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present. 1 fig.

Fortier, N.E.; Fritz, J.S.

1990-11-13

371

Shape Determination for Deformed Cavities  

SciTech Connect

A realistic superconducting RF cavity has its shape deformed comparing to its designed shape due to the loose tolerance in the fabrication process and the frequency tuning for its accelerating mode. A PDE-constrained optimization problem is proposed to determine the deformation of the cavity. A reduce space method is used to solve the PDE-constrained optimization problem where design sensitivities were computed using a continuous adjoint approach. A proof-of-concept example is given in which the deformation parameters of a single cavity-cell with two different types of deformation were computed.

Lee, Lie-Quan; Akcelik, Volkan; Chen, Sheng; Ge, Lixin; Li, Zenghai; Ng, Cho; Xiao, Liling; Ko, Kwok; /SLAC; Ghattas, Omar; /Texas U.

2006-10-04

372

Structure determination of enterovirus 71  

SciTech Connect

Enterovirus 71 is a picornavirus that causes hand, foot and mouth disease but may induce fatal neurological illness in infants and young children. Enterovirus 71 crystallized in a body-centered orthorhombic space group with two particles in general orientations in the crystallographic asymmetric unit. Determination of the particle orientations required that the locked rotation function excluded the twofold symmetry axes from the set of icosahedral symmetry operators. This avoided the occurrence of misleading high rotation-function values produced by the alignment of icosahedral and crystallographic twofold axes. Once the orientations and positions of the particles had been established, the structure was solved by molecular replacement and phase extension.

Plevka, Pavel; Perera, Rushika; Cardosa, Jane; Kuhn, Richard J.; Rossmann, Michael G. (Purdue); (Sentinext)

2013-02-20

373

Measuring times to determine positions  

E-print Network

Among the first devices used to measure the time we find the sundials and the water-clocks, as told by Vitruvius in his book on the Architecture. The sundials work because of the shadows cast by a rod or pole, the gnomon, on their basements. Besides being an instrument able to measure the time intervals, the sundial provided information on Earth and heaven to the ancient astronomers. Here we discuss how this device is able to determine the latitude and the north-south direction. The problem of the longitude is also shortly discussed.

Sparavigna, Amelia Carolina

2012-01-01

374

Liquid chromatographic determination of water  

DOEpatents

A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present.

Fortier, Nancy E. (Fairfield, OH); Fritz, James S. (Ames, IA)

1990-11-13

375

Genetic sex determination and extinction.  

PubMed

Genetic factors can affect the probability of extinction either by increasing the effect of detrimental variants or by decreasing the potential for future adaptive responses. In a recent paper, Zayed and Packer demonstrate that low variation at a specific locus, the complementary sex determination (csd) locus in Hymenoptera (ants, bees and wasps), can result in a sharply increased probability of extinction. Their findings illustrate situations in which there is a feedback process between decreased genetic variation at the csd locus owing to genetic drift and decreased population growth, resulting in an extreme type of extinction vortex for these ecologically important organisms. PMID:16701470

Hedrick, Philip W; Gadau, Jürgen; Page, Robert E

2006-02-01

376

Determination of a mutational spectrum  

SciTech Connect

A method is disclosed of resolving (physically separating) mutant DNA from nonmutant DNA. A method is also described of defining or establishing a mutational spectrum or profile of alterations present in nucleic acid sequences from a sample to be analyzed, such as a tissue or body fluid. The present method is based on the fact that it is possible, through the use of DGGE, to separate nucleic acid sequences which differ by only a single base change and on the ability to detect the separate mutant molecules. The present invention, in another aspect, relates to a method for determining a mutational spectrum in a DNA sequence of interest present in a population of cells. The method of the present invention is useful as a diagnostic or analytical tool in forensic science in assessing environmental and/or occupational exposures to potentially genetically toxic materials (also referred to as potential mutagens); in biotechnology, particularly in the study of the relationship between the amino acid sequence of enzymes and other biologically-active proteins or protein-containing substances and their respective functions; and in determining the effects of drugs, cosmetics and other chemicals for which toxicity data must be obtained. 3 figures.

Thilly, W.G.; Keohavong, P.

1991-09-03

377

Local determinants of contour interpolation.  

PubMed

Objects in our visual environment are perceived as integral wholes even when their retinal images are incomplete. We ask whether the perceptual precision of subjective interpolation between isolated image parts depends on the overall proportion of visible image information or rather on its geometrical arrangement. We used Varin-type subjective shapes that provide less physical stimulus information than Kanizsa-type figures because partially occluded solid inducers are replaced by partially occluded concentric arcs. We tested whether perceptual precision varies as a function of contour support, or alternatively, depends on the number of, and the distance between, line endings within the inducers. We measured performance in a probe localization task, where a small target is presented at different distances around a subjective boundary. Sensitivity, captured by the just noticeable position difference between in- and outside probes, crucially depended on the geometric arrangement of line ends in the Varin figures. This is objective evidence that the apparent subjective contour strength does not primarily depend on contour support but is determined by the number and the separation between inducers' line endings. The results suggest that neuronal mechanisms sensitive to highly localized 2D features are crucial for determining the perceived shape of visual objects. PMID:19146236

Maertens, Marianne; Shapley, Robert

2008-01-01

378

Determination of Silicon in Hydrazine  

NASA Technical Reports Server (NTRS)

Inductively coupled plasma-mass spectrometry (ICP-MS) is a highly sensitive technique sometimes used for the trace determination of silicon at a mass-to-charge (m/z) ratio of 28, the most abundant natural isotope of silicon. Unfortunately, ICP-MS is unable to differentiate between other sources of m/z 28 and false positive results for silicon will result when other sources of m/z 28 are present. Nitrogen was a major source of m/z 28 and contributes to the m/z 28 signal when hydrazine sample or nitric acid preservative is introduced into the plasma. Accordingly, this work was performed to develop a sample preparation step coupled with an ICP-MS analysis that minimized non-silicon sources of m/z 28. In the preparatory step of this method, the hydrazine sample was first decomposed predominately to nitrogen gas and water with copper-catalyzed hydrogen peroxide. In the analysis step, ICP-MS was used without nitric acid preservative in samples or standards. Glass, a potential source of silicon contamination, was also avoided where possible. The method was sensitive, accurate, and reliable for the determination of silicon in monopropellant grade hydrazine (MPH) in AF-E-332 elastomer leaching tests. Results for silicon in MPH were comparable to those reported in the literature for other studies.

McClure, Mark B.; Mast, Dion; Greene, Ben; Maes, Miguel J.

2006-01-01

379

Activity Summary: Determine a Blanket Balance  

E-print Network

Activity Summary: Determine a Blanket Balance NUFinancials Purchasing DetermineBlanketBalance This job aid describes how to determine the remaining balance of a Blanket purchase order. You can apply a Blanket Balance NUFinancials Purchasing DetermineBlanketBalance.doc Last Updated 3/7/2014 © 2014

Shull, Kenneth R.

380

Mars Observer orbit determination analysis  

NASA Technical Reports Server (NTRS)

Results are presented of a simulated orbit determination analysis for three phases of the Mars Observer mission (interplanetary cruise, orbit insertion, and mapping), together with a summary of orbital accuracies throughout the Mars Observer mission. The plan for achieving the navigation objectives of the Mars Observer mission is described. These objectives are to navigate the Mars Observer spacecraft to Mars and achieve accurate targeting at Mars; to propulsively maneuver the spacecraft into a 3-day period, capture orbit; to navigate the spacecraft into a 1.96-hr period low-altitude, nearly circular mapping orbit; and to maintain Mars Observer in the mapping orbit throughout the 687 days devoted for scientific data acquisition. Factors that will affect the spacecraft during each of the three phases are discussed.

Esposito, Pasquale; Roth, Duane; Demcak, Stuart

1991-01-01

381

Crystal face temperature determination means  

DOEpatents

An optically transparent furnace (10) having a detection apparatus (29) with a pedestal (12) enclosed in an evacuated ampule (16) for growing a crystal (14) thereon. Temperature differential is provided by a source heater (20), a base heater (24) and a cold finger (26) such that material migrates from a polycrystalline source material (18) to grow the crystal (14). A quartz halogen lamp (32) projects a collimated beam (30) onto the crystal (14) and a reflected beam (34) is analyzed by a double monochromator and photomultiplier detection spectrometer (40) and the detected peak position (48) in the reflected energy spectrum (44) of the reflected beam (34) is interpreted to determine surface temperature of the crystal (14).

Nason, Donald O. (Goleta, CA); Burger, Arnold (Nashville, TN)

1994-01-01

382

Attitude Determination Improvements for GOES  

NASA Technical Reports Server (NTRS)

In this paper, a summary of the basic simulation parameters and results of a new study for the Geostationary Operational Environmental Satellite (GOES) is shown. The study for GOES involves the simulation of minor modifications to the current spacecraft, so that the relative performance of these modifications can be analyzed. The first modification studies requires the placement of a baseline inertial reference unit, such as the Dry Rotor Inertial Reference Unit or the Hemispherical Resonator Gyro onto the spacecraft. The imager/sounder assembly is currently used to obtain landmark and/or star observations in order to compensate for spacecraft motion and external disturbances through ground processing. The study uses the imager/sounder assembly as another attitude sensor for on-board attitude determination. Also the addition of star trackers is used to provide precise attitude knowledge.

Crassidis, John L.; Markley, F. Landis; Kyle, Arthur M.; Kull, Kathie

1996-01-01

383

Prospective errors determine motor learning  

PubMed Central

Diverse features of motor learning have been reported by numerous studies, but no single theoretical framework concurrently accounts for these features. Here, we propose a model for motor learning to explain these features in a unified way by extending a motor primitive framework. The model assumes that the recruitment pattern of motor primitives is determined by the predicted movement error of an upcoming movement (prospective error). To validate this idea, we perform a behavioural experiment to examine the model’s novel prediction: after experiencing an environment in which the movement error is more easily predictable, subsequent motor learning should become faster. The experimental results support our prediction, suggesting that the prospective error might be encoded in the motor primitives. Furthermore, we demonstrate that this model has a strong explanatory power to reproduce a wide variety of motor-learning-related phenomena that have been separately explained by different computational models. PMID:25635628

Takiyama, Ken; Hirashima, Masaya; Nozaki, Daichi

2015-01-01

384

Structure determination of lipid bilayers.  

PubMed Central

A method of determining the phases of X-ray reflections from oriented model membrane systems at low resolution is described. The method involves deconvolution and requires that d less than or equal to 2v where v is the width of the head group region within the bilayer and d is the thickness of the bilayer. The method can be used with a single set of X-ray data and applies to lipid bilayers which have a relatively constant density in the hydrocarbon region. Phases for the first five or six orders of phosphatidylethanolamine and lecithin are derived. A refined analysis based upon deconvolution but using information inherent in the Fourier profile is also described. PMID:698345

Worthington, C R; Kharf, R S

1978-01-01

385

Detecting determinism from point processes  

NASA Astrophysics Data System (ADS)

The detection of a nonrandom structure from experimental data can be crucial for the classification, understanding, and interpretation of the generating process. We here introduce a rank-based nonlinear predictability score to detect determinism from point process data. Thanks to its modular nature, this approach can be adapted to whatever signature in the data one considers indicative of deterministic structure. After validating our approach using point process signals from deterministic and stochastic model dynamics, we show an application to neuronal spike trains recorded in the brain of an epilepsy patient. While we illustrate our approach in the context of temporal point processes, it can be readily applied to spatial point processes as well.

Andrzejak, Ralph G.; Mormann, Florian; Kreuz, Thomas

2014-12-01

386

Nondestructive Determination of Bond Strength  

NASA Technical Reports Server (NTRS)

Although many nondestructive techniques have been applied to detect disbonds in adhesive joints, no absolutely reliable nondestructive method has been developed to detect poor adhesion and evaluate the strength of bonded joints prior to the present work which used nonlinear ultrasonic methods to investigate adhesive bond cure conditions. Previously, a variety of linear and nonlinear ultrasonic methods with water coupling had been used to study aluminum-adhesive-aluminum laminates, prepared under different adhesive curing conditions, for possible bond strength determination. Therefore, in the course of this research effort, a variety of finite-amplitude experimental methods which could possibly differentiate various cure conditions were investigated, including normal and oblique incidence approaches based on nonlinear harmonic generation as well as several non-collinear two-wave interaction approaches. Test samples were mechanically scanned in various ways with respect to the focus of a transmitting transducer operated at several variable excitation frequencies and excitation levels. Even when powerful sample-related resonances were exploited by means of a frequency scanning approach, it was very difficult to isolate the nonlinear characteristics of adhesive bonds. However, a multi-frequency multi-power approach was quite successful and reliable. Ultrasonic tone burst signals at increasing power levels, over a wide frequency range, were transmitted through each bond specimen to determine its excitation dependent nonlinear harmonic resonance behavior. Relative amplitude changes were observed particularly in the higher harmonic spectral data and analyzed using a local displacement and strain analysis in the linear approximation. Two analysis approaches of the excitation-dependent data at specific resonances were found to be quite promising. One of these approaches may represent a very robust algorithm for classifying an adhesive bond as being properly cured or not. Another approach, in addition to differentiation between various cure conditions, may even provide information with respect to the bond strength. Several technical papers were published during the course of this research and a summary is presented in the Ph.D. dissertation of Tobias P. Berndt, a graduate student financially supported by this NASA Grant.

2000-01-01

387

Determinants of human population growth.  

PubMed Central

The 20th century has seen unprecedented growth of the human population on this planet. While at the beginning of the century the Earth had an estimated 1.6 billion inhabitants, this number grew to 6.1 billion by the end of the century, and further significant growth is a near certainty. This paper tries to summarize what factors lie behind this extraordinary expansion of the human population and what population growth we can expect for the future. It discusses the concept of demographic transition and the preconditions for a lasting secular fertility decline. Recent fertility declines in all parts of the world now make it likely that human population growth will come to an end over the course of this century, but in parts of the developing world significant population growth is still to be expected over the coming decades. The slowing of population growth through declining birth rates, together with still increasing life expectancy, will result in a strong ageing of population age structure. Finally, this paper presents a global level systematic analysis of the relationship between population density on the one hand, and growth and fertility rates on the other. This analysis indicates that in addition to the well-studied social and economic determinants, population density also presents a significant factor for the levels and trends of human birth rates. PMID:12396512

Lutz, Wolfgang; Qiang, Ren

2002-01-01

388

Ballistic projectile trajectory determining system  

DOEpatents

A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile. 8 figs.

Karr, T.J.

1997-05-20

389

Ballistic projectile trajectory determining system  

DOEpatents

A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile.

Karr, Thomas J. (Alamo, CA)

1997-01-01

390

Genetic determinants of athletic performance.  

PubMed

An extraordinary revolution in medical research has taken place over the past decade, enabled by the completion of the first human genome sequence in 2001. The Human Genome Project (HGP) has resulted in the 6 billion letter reference human genome sequence and the ultra-high throughput technologies used by medical researchers to identify correlations between positions within the human genome (genotypes) and diseases or traits (phenotypes). Just as every human disease has a genetic component, so too does every human trait. The vast majority of these diseases and traits also have an environmental component that works in conjunction with the body's hardwiring to produce the resultant phenotype- termed "complex genetic traits". A derivative of the HGP has been a deeper understanding not only of diseases but of normal human variability across the population, including aspects of athleticism. The technologies also now exist for consumers to cheaply gain access to variations in the genetic code that are correlated to traits that confer aspects of longevity, memory performance, athleticism and a multitude of others there-through gaining insight into propensities. Communication of propensity to a phenotype such as athletic performance is fraught with technical, legal (e.g., patents), social and ethical issues. That being said, the information is available, has benefit in some cases, and will be utilized in the future. Given that the "genie is out of the bottle" with respect to our ability to deliver this genetic information to individuals, over the past decade our team has worked diligently to craft the appropriate testing and communication paradigms for complex traits. Here we discuss several of the major risks and benefits of this type of testing for athletic performance. It is important to understand the limitations of genetic information in determining the vast majority of traits. PMID:22827596

Stephan, Dietrich A

2012-12-01

391

Quantitative description of temperature induced self-aggregation thermograms determined by differential scanning calorimetry.  

PubMed

A novel thermodynamic approach for the description of differential scanning calorimetry (DSC) experiments on self-aggregating systems is derived and presented. The method is based on a mass action model where temperature dependence of aggregation numbers is considered. The validity of the model was confirmed by describing the aggregation behavior of poly(ethylene oxide)-poly(propylene oxide) block copolymers, which are well-known to exhibit a strong temperature dependence. The quantitative description of the thermograms could be performed without any discrepancy between calorimetric and van 't Hoff enthalpies, and moreover, the aggregation numbers obtained from the best fit of the DSC experiments are in good agreement with those obtained by light scattering experiments corroborating the assumptions done in the derivation of the new model. PMID:23171124

Chiappisi, Leonardo; Lazzara, Giuseppe; Gradzielski, Michael; Milioto, Stefana

2012-12-21

392

Tetracycline determines the conformation of its aptamer at physiological magnesium concentrations.  

PubMed

Synthetic riboswitches are versatile tools for the study and manipulation of biological systems. Yet, the underlying mechanisms governing its structural properties and regulation under physiological conditions are poorly studied. We performed spectroscopic and calorimetric experiments to explore the folding kinetics and thermodynamics of the tetracycline-binding aptamer, which can be employed as synthetic riboswitch, in the range of physiological magnesium concentrations. The dissociation constant of the ligand-aptamer complex was found to strongly depend on the magnesium concentration. At physiological magnesium concentrations, tetracycline induces a significant conformational shift from a compact, but heterogeneous intermediate state toward the completely formed set of tertiary interactions defining the regulation-competent structure. Thus, the switching functionality of the tetracycline-binding aptamer appears to include both a conformational rearrangement toward the regulation-competent structure and its thermodynamic stabilization. PMID:25517161

Reuss, Andreas J; Vogel, Marc; Weigand, Julia E; Suess, Beatrix; Wachtveitl, Josef

2014-12-16

393

3 CFR - Presidential Determination on Sudan  

Code of Federal Regulations, 2011 CFR

... false Presidential Determination on Sudan Presidential Documents Other Presidential...2010 Presidential Determination on Sudan Memorandum for the Secretary of State...to facilitate the referendum in Southern Sudan pursuant to the Comprehensive Peace...

2011-01-01

394

38 CFR 75.116 - Secretary determination.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Secretary determination. 75.116 Section 75.116 Pensions, Bonuses, and Veterans' Relief DEPARTMENT...INFORMATION SECURITY MATTERS Data Breaches § 75.116 Secretary determination. (a) Upon...

2010-07-01

395

48 CFR 25.203 - Preaward determinations.  

Code of Federal Regulations, 2012 CFR

...ACQUISITION REGULATION SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American Act-Construction Materials 25.203 Preaward determinations...contracting officer a determination concerning the inapplicability of the Buy American Act for specifically identified construction...

2012-10-01

396

48 CFR 25.205 - Postaward determinations.  

Code of Federal Regulations, 2013 CFR

...SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American Act-Construction Materials ...determination regarding the inapplicability of the Buy American Act after contract award...determination regarding the inapplicability of the Buy American Act made after contract...

2013-10-01

397

48 CFR 25.205 - Postaward determinations.  

Code of Federal Regulations, 2011 CFR

...SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American Act-Construction Materials ...determination regarding the inapplicability of the Buy American Act after contract award...determination regarding the inapplicability of the Buy American Act made after contract...

2011-10-01

398

48 CFR 25.205 - Postaward determinations.  

Code of Federal Regulations, 2012 CFR

...SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American Act-Construction Materials ...determination regarding the inapplicability of the Buy American Act after contract award...determination regarding the inapplicability of the Buy American Act made after contract...

2012-10-01

399

48 CFR 25.205 - Postaward determinations.  

...SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American-Construction Materials 25...determination regarding the inapplicability of the Buy American statute after contract award...determination regarding the inapplicability of the Buy American statute made after contract...

2014-10-01

400

48 CFR 25.205 - Postaward determinations.  

Code of Federal Regulations, 2010 CFR

...SOCIOECONOMIC PROGRAMS FOREIGN ACQUISITION Buy American Act-Construction Materials ...determination regarding the inapplicability of the Buy American Act after contract award...determination regarding the inapplicability of the Buy American Act made after contract...

2010-10-01

401

48 CFR 370.505 - Responsibility determinations.  

Code of Federal Regulations, 2010 CFR

...SPECIAL PROGRAMS AFFECTING ACQUISITION Acquisitions Under the Buy Indian Act 370.505 Responsibility determinations. (a) The Contracting Officer may award a contract under the Buy Indian Act only if the Contracting Officer determines...

2010-10-01

402

A determinant of generalized Fibonacci numbers  

E-print Network

We evaluate a determinant of generalized Fibonacci numbers, thus providing a common generalization of several determinant evaluation results that have previously appeared in the literature, all of them extending Cassini's identity for Fibonacci numbers.

Krattenthaler, Christian

2012-01-01

403

Two determinants with Fibonacci and Lucas entries  

Microsoft Academic Search

In this short note, we study two families of determinants the entries of which are linear functions of Fibonacci or Lucas numbers. The results are rather simple, and the two determinants only differ by a constant.

Harris Kwong

2007-01-01

404

19 CFR 351.210 - Final determination.  

Code of Federal Regulations, 2010 CFR

...210 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT...determinations, and the effects of final determinations...rates, if any. (d) Effect of affirmative final...the Act). (k) Effect of negative final...

2010-04-01

405

20 CFR 410.627 - Reconsidered determination.  

Code of Federal Regulations, 2010 CFR

... 410.627 Section 410.627 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL COAL MINE HEALTH AND SAFETY...Determinations, Administrative Review, Finality of Decisions, and Representation of Parties § 410.627 Reconsidered determination....

2010-04-01

406

Combining Multiple Indicators to Determine Conservation Status  

E-print Network

Combining Multiple Indicators to Determine Conservation Status Based on Expert Preferences of Resource Management (Planning) Title of Project: Combining multiple indicators to determine conservation on using multiple indicators, and most methods for combining indicators either assume that all indicators

407

Sex Determination in Flies, Fruitflies and Butterflies  

Microsoft Academic Search

Sex determination mechanisms, differing in their modality, are widely represented in all the various animal taxa, even at the intraspecific level. Within the highly diversified Class Insecta, Drosophila has been used to unravel the mechanistic molecular and genetic interactions that are involved in sex determination. Indeed, the molecularly characterized genes of the Drosophila sex determination hierarchy X:A> Sxl> tra> dsxhave

G. Saccone; A. Pane; L. C. Polito

2002-01-01

408

Sex determination: insights from the chicken  

E-print Network

genes have recently emerged. The Z-linked gene, DMRT1, supports the Z-dosage model of avian sex in gonadal sex dif- ferentiation. However, several genes shown to be critical for mammalian sex determination determination. Two novel W-linked genes, ASW and FET1, represent candidate female determinants. BioEssays 26

Meyers, Ron

409

Methods for threshold determination in multiplexed assays  

DOEpatents

Methods for determination of threshold values of signatures comprised in an assay are described. Each signature enables detection of a target. The methods determine a probability density function of negative samples and a corresponding false positive rate curve. A false positive criterion is established and a threshold for that signature is determined as a point at which the false positive rate curve intersects the false positive criterion. A method for quantitative analysis and interpretation of assay results together with a method for determination of a desired limit of detection of a signature in an assay are also described.

Tammero, Lance F. Bentley; Dzenitis, John M; Hindson, Benjamin J

2014-06-24

410

19 CFR 351.205 - Preliminary determination.  

Code of Federal Regulations, 2010 CFR

...Customs Duties INTERNATIONAL TRADE ADMINISTRATION...determinations, and the effects of affirmative...derogation of an international undertaking on...United States Trade Representative...309. (d) Effect of...

2010-04-01

411

Uncertainty of in-flight thrust determination  

NASA Technical Reports Server (NTRS)

Methods for estimating the measurement error or uncertainty of in-flight thrust determination in aircraft employing conventional turbofan/turbojet engines are reviewed. While the term 'in-flight thrust determination' is used synonymously with 'in-flight thrust measurement', in-flight thrust is not directly measured but is determined or calculated using mathematical modeling relationships between in-flight thrust and various direct measurements of physical quantities. The in-flight thrust determination process incorporates both ground testing and flight testing. The present text is divided into the following categories: measurement uncertainty methodoogy and in-flight thrust measurent processes.

Abernethy, Robert B.; Adams, Gary R.; Steurer, John W.; Ascough, John C.; Baer-Riedhart, Jennifer L.; Balkcom, George H.; Biesiadny, Thomas

1986-01-01

412

Thermodynamic properties of anthophyllite and talc: corrections and discussion of calorimetric data  

USGS Publications Warehouse

Arithmetic errors in calculating heat capacity values (Krupka, 1984; Krupka et al, 1985a) for anthophyllite and several errors in the Hess cycles utilized to derive enthalpies of formation of anthophyllite and talc are identified, and revised values are reported. -from Author

Hemingway, B.S.

1991-01-01

413

Crystallization kinetics of poly-(lactic acid) with and without talc: Optical microscopy and calorimetric analysis  

NASA Astrophysics Data System (ADS)

Poly-(lactic acid) or PLA is a biodegradable polymer synthesized from renewable resources. Recently, the discovery of new polymerization routes has allowed increasing the produced volumes. As a consequence, PLA is becoming of great interest for reducing the dependence on petroleum-based plastics. Because of its interesting mechanical properties, PLA is seen as a potential substitute for some usual polymers. However, its relatively slow crystallization kinetics can be a disadvantage with regard to industrial applications. The crystallization kinetics of PLA can be enhanced by adding nucleating agents, which also influences on crystalline morphology and rheological behavior. In the present work, the isothermal quiescent crystallization kinetics of both neat PLA and PLA/talc composite (5 wt% talc) are investigated. The effects of talc on the overall crystallization kinetics and on the crystalline morphology are analyzed using both optical microscopy measurements and thermal analysis by differential scanning calorimetry.

Refaa, Z.; Boutaous, M.; Rousset, F.; Fulchiron, R.; Zinet, M.; Xin, S.; Bourgin, P.

2014-05-01

414

Scanning calorimetric and EPR studies on the thermal stability of actin  

Microsoft Academic Search

The thermal stability of actin isolated from skeletal muscle was studied in monomer and polymerized forms using DSC and EPR spectroscopy. Actin was labelled with the paramagnetic derivative of maleimide at the reactive thiol site Cys-374 in the C-terminal subdomain-1. The unfolding of actin induced by heating in the range 10–70°C resulted in a single transition: the transition temperature was

Dénes Lörinczy; Joseph Belágyi

1995-01-01

415

Dielectric and Calorimetric Studies of PLZT-P(VDF\\/TrFE) Ceramics-Copolymer Composite  

Microsoft Academic Search

Dielectric dynamics in PLZT-P(VDF\\/TrFE) ceramics-copolymer composite has been studied by measurements of the temperature and frequency-dependent linear and third-order nonlinear dielectric constants. A paraelectric-to-ferroelectric phase transition in the crystalline region and a dielectric relaxation, which is a dynamic manifestation of the glassy-to-rubbery state transition in the amorphous phase of the system, were detected. The nature of the paraelectric-to-ferroelectric phase transition

V. BOBNAR; B. VODOPIVEC; Z. KUTNJAK; M. KOSEC; A. LEVSTIK; B. HILCZER

2004-01-01

416

Calorimetric study on mechanically milled aluminum and multiwall carbon nanotube composites  

SciTech Connect

Pure aluminum reinforced with carbon nanotube (CNT) composites have been prepared by high energy attritor milling up to 48 hrs. Differential Scanning Calorimetry (DSC) has been carried out to investigate apparent activation energy and order of the reaction between carbon nanotubes and aluminum by Kissinger equation and Crane equation under non-isothermal conditions. The DSC results clearly reveal that an exothermic reaction occurs before the melting of aluminum. The effect of milling time on the initiation of this exothermic reaction has been studied. The peak temperature of the reaction of carbon nanotubes and aluminum is found to depend on the heating rate during the continuous heating. Apparent activation energy was found to get doubled after milling for 36 hrs compared to 24 hrs milled samples. The mechanism of the reaction kinetics which depends on reaction order is instantaneous nucleation and one dimensional growth for both samples. Formation of Al{sub 4}C{sub 3} was confirmed by X-ray diffraction (XRD) of as-milled powders and after performing DSC of the milled powders. Highlights: {yields} Attritor milling used for processing Al-CNT composites. {yields} Powder morphology as a function of time studied. {yields} Apparent activation energy and order of the reaction calculated for Al{sub 4}C{sub 3} formation. {yields} Apparent activation energy increases two fold with increase in milling time from 24 to 36 hours.

Nayan, Niraj, E-mail: metnayan@gmail.com; Murty, S.V.S.N.; Sharma, S.C.; Kumar, K. Sree; Sinha, P.P.

2011-11-15

417

Calorimetric properties of water and triacylglycerols in fern spores relating to storage at cryogenic temperatures.  

PubMed

Storing spores is a promising method to conserve genetic diversity of ferns ex situ. Inappropriate water contents or damaging effects of triacylglycerol (TAG) crystallization may cause initial damage and deterioration with time in spores placed at -15 degrees C or liquid nitrogen temperatures. We used differential scanning calorimetry (DSC) to monitor enthalpy and temperature of water and TAG phase transitions within spores of five fern species: Pteris vittata, Thelypteris palustris, Dryopteris filix-mas, Polystichum aculeatum, Polystichum setiferum. The analyses suggested that these fern spores contained between 26% and 39% TAG, and were comprised of mostly oleic (P. vittata) or linoleic acid (other species) depending on species. The water contents at which water melting events were first observable ranged from 0.06 (P. vittata) to 0.12 (P. setiferum)gH(2)Og(-1)dry weight, and were highly correlated with water affinity parameters. In spores containing more than 0.09 (P. vittata) to 0.25 (P. setiferum)gH(2)Og(-1)dry weight, some water partitioned into a near pure water fraction that melted at about 0 degrees C. These sharp peaks near 0 degrees C were associated with lethal freezing treatments. The enthalpy of water melting transitions was similar in fern spores, pollen and seeds; however, the unfrozen water content was much lower in fern spores compared to other forms of germplasm. Though there is a narrow range of water contents appropriate for low temperature storage of fern spores, water content can be precisely manipulated to avoid both desiccation and freezing damage. PMID:17553480

Ballesteros, Daniel; Walters, Christina

2007-08-01

418

Differential scanning calorimetric analysis of antifreeze protein activity in the common mealworm, Tenebrio molitor.  

PubMed

Antifreeze proteins (AFP) are able to inhibit the growth of ice-crystals at temperatures below the equilibrium freezing point (Tf) of hemolymph. The analysis of AFP activity has commonly involved the use of direct microscopic observation of a sample following inoculation with ice. The resulting activity, defined as the amount of thermal hysteresis observed between Tf and the subsequent rapid growth of ice, has been reported to range up to 7 degrees C. However, most studies report high level of variation, possibly due to ice-crystal size variability and the presence of non-visible ice nuclei. We describe a new method of analysis of AFP activity using differential scanning calorimetry (DSC). DSC analysis reveals much higher activity, up to 10 degrees C, with less variation observed within a sample, and is not subject to the difficulty of accurate assessment of ice-crystal volume. PMID:3191140

Hansen, T N; Baust, J G

1988-11-23

419

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

ERIC Educational Resources Information Center

In this laboratory experiment, general chemistry students measure the heating curves for three different systems: (i) 500 g of room-temperature water heated by a small desk lamp, (ii) 500 g of an ice-water mixture warmed by conduction with room-temperature surroundings, and (iii) 500 g of an ice-water mixture heated by a small desk lamp and by…

Burley, Joel D.; Johnston, Harold S.

2007-01-01

420

Thermodynamics of IonInduced RNA Folding in the Hammerhead Ribozyme: An Isothermal Titration Calorimetric Study †  

Microsoft Academic Search

The hammerhead ribozyme undergoes a well-defined two-stage conformational folding process, induced by the binding of magnesium ions. In this study, we have used isothermal titration calorimetry to analyze the thermodynamics of magnesium binding and magnesium ion-induced folding of the ribozyme. Binding to the natural sequence ribozyme is strongly exothermic and can be analyzed in terms of sequential interaction at two

Christian Hammann; Alan Cooper; David M. J. Lilley

2001-01-01

421

Effect of anti-inflammatory drugs in phosphatidylcholine membranes: A fluorescence and calorimetric study  

NASA Astrophysics Data System (ADS)

NSAIDs are the most prescribed drugs for inflammation, and their use is associated with severe gastrointestinal toxicity. This work focuses on the interaction of NSAIDs with membranes, specifically, on their ability to affect the lipid dynamic properties, since this may explain the compromising effects on the integrity of gastric barrier. Studies covered the assessment of drug-membrane/water partition coefficient and location by derivative spectroscopy and fluorescence quenching techniques and effects on membrane biophysics by DSC. Results indicate that the NSAIDs studied have membrane destabilizing effects, which could be transposed to similar effects in the stomach's phospholipid layer justifying their toxicity.

Lúcio, M.; Nunes, C.; Gaspar, D.; Go??bska, K.; Wisniewski, M.; Lima, J. L. F. C.; Brezesinski, G.; Reis, S.

2009-03-01

422

Calorimetric Behavior of Phosphatidylcholine/Phosphatidylethanolamine Bilayers is Compatible with the Superlattice Model  

PubMed Central

Differential scanning calorimetry was used to study the phase behavior of binary lipid bilayers consisting of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of varying acyl chain length. A 2-state transition model was used to resolve the individual transition components, and the 2-state transition enthalpy, the relative enthalpy and the transition temperature of each component were plotted as a function of composition. Intriguingly, abrupt changes in these thermodynamic parameters were observed at or close to many “critical” XPE values predicted by the Superlattice model proposing that phospholipids with different headgroups tend to adopt regular rather than random lateral distributions. Statistical analysis indicated that the agreement between the observed and predicted “critical” compositions is highly significant. Accordingly, these data provide strong evidence for that the molecules in PC/PE bilayers tend to adopt regular, superlattice-like lateral arrangements, which could be involved in the regulation of the lipid compositions of biological membranes. PMID:22251448

Cheng, Kwan Hon; Virtanen, Jorma; Somerharju, Pentti

2012-01-01

423

Conductometric and calorimetric studies of the serially diluted and agitated solutions  

Microsoft Academic Search

We systematically analysed the experimental data related to the specific conductivities and heats in excess of several serially\\u000a diluted and agitated solutions (SDA for short). For all of the analysed samples, we found that both the excess conductivity,\\u000a ?E (?S cm?1), and excess heat, Q\\u000a mixE (J kg?1), varied with the age of the sample (up to 2 years of

P. Belon; V. Elia; L. Elia; M. Montanino; E. Napoli; M. Niccoli

2008-01-01

424

Calorimetric investigation of diclofenac drug binding to a panel of moderately glycated serum albumins.  

PubMed

Glycation alters the drug binding properties of serum proteins and could affect free drug concentrations in diabetic patients with elevated glycation levels. We investigated the effect of bovine serum albumin glycation by eight physiologically relevant glycation reagents (glucose, ribose, carboxymethyllysine, acetoin, methylglyoxal, glyceraldehyde, diacetyl and glycolaldehyde) on diclofenac drug binding. We used this non-steroidal anti-inflammatory drug diclofenac as a paradigm for acidic drugs with high serum binding and because of its potential cardiovascular risks in diabetic patients. Isothermal titration calorimetry showed that glycation reduced the binding affinity Ka of serum albumin and diclofenac 2 to 6-fold by reducing structural rigidity of albumin. Glycation affected the number of drug binding sites in a glycation reagent dependent manner and lead to a 25% decrease for most reagent, expect for ribose, with decreased by 60% and for the CML-modification, increased the number of binding sites by 60%. Using isothermal titration calorimetry and differential scanning calorimetry we derived the complete thermodynamic characterization of diclofenac binding to all glycated BSA samples. Our results suggest that glycation in diabetic patients could significantly alter the pharmacokinetics of the widely used over-the-counter NSDAI drug diclofenac and with possibly negative implications for patients. PMID:24751671

Indurthi, Venkata S K; Leclerc, Estelle; Vetter, Stefan W

2014-08-01

425

Calorimetric and dielectric study of organic ferroelectrics, phenazine-chloranilic acid, and its bromo analog  

NASA Astrophysics Data System (ADS)

The heat capacities of single crystals of organic ferroelectric complexes phenazine-chloranilic acid (Phz-H2ca) and phenazine-bromanilic acid (Phz-H2ba) were measured. At temperatures below those of the reported ferroelectric phase transitions, heat capacity anomalies due to successive phase transitions were found in both complexes. Excess entropies involved in the low-temperature successive phase transitions are much larger than those due to the ferroelectric phase transitions. The temperature dependence of the complex dielectric constants showed the existence of multiple dielectric relaxation modes in both complexes and their deuterated analogs (Phz-D2ca and Phz-D2ba). We discuss the possibility of concerted hopping of neighboring protons within a hydrogen-bonded chain while taking into account the one-dimensional nature of the chain.

Amano, Masakazu; Yamamura, Yasuhisa; Sumita, Masato; Yasuzuka, Syuma; Kawaji, Hitoshi; Atake, Tooru; Saito, Kazuya

2009-01-01

426

Calorimetric and dielectric study of organic ferroelectrics, phenazine-chloranilic acid, and its bromo analog.  

PubMed

The heat capacities of single crystals of organic ferroelectric complexes phenazine-chloranilic acid (Phz-H(2)ca) and phenazine-bromanilic acid (Phz-H(2)ba) were measured. At temperatures below those of the reported ferroelectric phase transitions, heat capacity anomalies due to successive phase transitions were found in both complexes. Excess entropies involved in the low-temperature successive phase transitions are much larger than those due to the ferroelectric phase transitions. The temperature dependence of the complex dielectric constants showed the existence of multiple dielectric relaxation modes in both complexes and their deuterated analogs (Phz-D(2)ca and Phz-D(2)ba). We discuss the possibility of concerted hopping of neighboring protons within a hydrogen-bonded chain while taking into account the one-dimensional nature of the chain. PMID:19173527

Amano, Masakazu; Yamamura, Yasuhisa; Sumita, Masato; Yasuzuka, Syuma; Kawaji, Hitoshi; Atake, Tooru; Saito, Kazuya

2009-01-21

427

Functional Energetic Landscape in the Allosteric Regulation of Muscle Pyruvate Kinase I. Calorimetric Study  

PubMed Central

Rabbit muscle pyruvate kinase (RMPK) is an important allosteric enzyme of the glycolytic pathway catalyzing a transfer of the phosphate from phosphoenolpyruvate (PEP) to ADP. The energetic landscape of the allosteric regulatory mechanism of RMPK was characterized by isothermal titration calorimetry (ITC) in the temperature range from 4°C to 45°C. ITC data for RMPK binding to substrates PEP and ADP, for the allosteric inhibitor Phe, as well as for combination of ADP and Phe were globally analyzed. The thermodynamic parameters characterizing the linked-multiple- equilibria system were extracted. Four novel insights were uncovered 1. The binding preference of ADP for either the T- or R-state is temperature dependent; namely, more favorably to the T- and R-state at high and low temperature, respectively. This cross over of affinity towards R and T-state implies that ADP plays a complex role in modulating the allosteric behavior of RMPK. Depending on the temperature, binding of ADP can regulate RMPK activity by favoring the enzyme to either the R- or T-state. 2. The binding of Phe is negatively coupled to that of ADP i.e. Phe and ADP prefer not to bind to the same subunit of RMPK. 3. The release or absorption of protons linked to the various equilibria is specific to the particular reaction. As a consequence, pH will exert a complex effect on these linked equilibria resulting in proton being an allosteric regulatory ligand of RMPK. 4. The R?T equilibrium is accompanied by a significant ?Cp rendering RMPK most sensitive to temperature under physiological conditions. During muscle activity, both pH and temperature fluctuations are known to happen; thus, results of this study are physiologically relevant. PMID:19719244

Herman, Petr; Lee, J. Ching

2009-01-01

428

Calorimetric studies of 7000 series aluminum alloys: II. Comparison of 7075, 7050 and RX720 alloys  

Microsoft Academic Search

Differential scanning calorimetry (DSC) in conjunction with transmission electron microscopy (TEM) are used to characterize\\u000a the matrix precipitate structure of high strength and overaged tempers of three 7000 series aluminum alloys. Excellent consistency\\u000a exists between the DSC results, based on the dissolution behavior of existing precipitates, and TEM observations. Comparison\\u000a is made between matrix precipitate constituency and mechanical properties. A

Philip N. Adler; Richard Deiasi

1977-01-01

429

Gravimetric analysis and differential scanning calorimetric studies on glycerin-induced skin hydration.  

PubMed

A thermal gravimetric analysis (TGA) and a differential scanning calorimetry (DSC) were carried out to characterize the water property and an alteration of lipid phase transition of stratum corneum (SC) by glycerin. In addition, the relationship between steady state skin permeation rate and skin hydration in various concentrations of glycerin was investigated. Water vapor absorption-desorption was studied in the hairless mouse stratum corneum. Dry SC samples were exposed to different conc. of glycerin (0-50%) followed by exposure to dry air and the change in weight property was monitored over time by use of TGA. In DSC study, significant decrease in DeltaH of the lipid transition in 10% glycerin and water treated sample: the heat of lipid transition of normal, water, 10% glycerin treated SC were 6.058, 4.412 and 4.316 mJ/mg, respectively. In 10% glycerin treated SCs, the Tc of water shifts around 129 degrees C, corresponding to the weakly bound secondary water. In 40% glycerin treated SC, the Tc of water shifts to 144 degrees C corresponding to strongly bound primary water. There was a good correlation between the hydration property of the skin and the steady state skin flux with the correlation coefficient (r2=0.94). As the hydration increased, the steady state flux increased. As glycerin concentration increased, hydration property decreased. High diffusivity induced by the hydration effect of glycerin and water could be the major contributing factor for the enhanced skin permeation of nicotinic acid (NA). PMID:18087820

Lee, Ae-Ri Cho; Moon, Hee Kyung

2007-11-01

430

Investigations into the thermal performance of multilayer insulation (300-77 K) Part 1: Calorimetric studies  

NASA Astrophysics Data System (ADS)

The thermal performance of multilayer insulation (MLI), consisting of double aluminized Mylar radiation shields and nylon net thermal spacers, was evaluated using a double guarded cylindrical calorimeter and a tank calorimeter over the temperature range 300-77 K. The degradation in the effective thermal conductivity of MLI was evaluated to be 1.68 using the calorimeters. The optimum number of layers for the MLI was 40 to 50 at a layer density of 25 layers cm -1. The temperature profile and heat flux through the MLI were obtained as a function of vacuum level for different numbers of insulation layers. The temperature profile of the MLI indicates the relative predominance of the conduction and radiation components of heat transfer through the insulation. It is observed that for a given number of layers, the temperature of a specific layer between the cold and warm boundaries decreases with an increase in chamber pressure and vice versa.

Jacob, S.; Kasthurirengan, S.; Karunanithi, R.

431

A calorimetric investigation of fiber\\/matrix reactions in fiber-reinforced aluminum alloy 339  

Microsoft Academic Search

The fiber\\/matrix reaction in aluminum composites reinforced with discontinuous ceramic fibers is critical to the formation of a strong interfacial bond. The reactions at ?500°C in Kaowool- and Saffil-reinforced 339 aluminum casting alloys were measured by differential isothermal calorimetry. The reaction exotherm is superimposed upon an endotherm associated with dissolution of magnesium-containing precipitates in the aluminum matrix. The time constants

George W. Smith; William J. Baxter; Anil K. Sachdev

2000-01-01

432

New Thermodynamic Data for Liquid Aluminum-Magnesium Alloys from emf, Vapor Pressures, and Calorimetric Studies  

Microsoft Academic Search

Experimental thermodynamic studies of liquid Al-Mg alloys have been performed by several methods resulting in: (1) Mg activities\\u000a from galvanic cells with liquid electrolytes at temperatures from\\u000a 910 to 1070 K, at XMg = 0.1 to 0.7 and for the dilute range when XMg = 0.0126 to 0.1430 at 927 K; (2) Mg activities from the emf method with solid

Z. Moser; W. Zakulski; K. Rzyman; W. Gasior; Z. Panek; I. Katayama; T. Matsuda; Y. Fukuda; T. Iida; Z. Zajaczkowski; J. Botor

1998-01-01

433

Heavy metal effects on the metabolic activity of Elliptio complanata: A calorimetric method  

SciTech Connect

The effects of short time exposure to mercury (Hg{sup 2+}), cadmium (Cd{sup 2+}), and copper (Cu{sup 2+}) ions on the metabolic activity of gill tissue from the freshwater bivalve Elliptio complanata were investigated by isothermal calorimetry and respirometry. Metabolic heat rates were altered following exposure of gill tissue to these ions over the concentration range from 10{sup {minus}6} to 10{sup {minus}3} M. The effects of metal ions on metabolic heat rates were metal ion specific and time and concentration dependent. Treatment of tissue with low concentrations of Hg{sup 2+} and Cu{sup 2+} for short times caused stimulation of metabolic heat rates. Longer exposures and higher concentrations caused inhibition. Cadmium was inhibitory under all conditions tested. Treatment of mitochrondria isolated from gill and muscle tissues showed a similar pattern of stimulation of respiratory rate at low concentration and inhibition at higher concentration. Analysis of CO{sub 2} and O{sub 2} from the headspace gasses in the calorimeter ampule showed an enhancement of respiratory quotient (RQ, i.e., R{sub CO{sub 2}}/R{sub O{sub 2}} where R = rate) following addition of 10{sup {minus}3} M Cd{sup 2+} for 30 min. The microcalorimetric method proved to be a useful technique to assess toxicity of heavy metals on the gills of a freshwater bivalve. 12 refs., 7 figs., 3 tabs.

Cheney, M.A. [Rutgers, Univ., New Brunswick, NJ (United States); Criddle, R.S. [Univ. of California, Davis, CA (United States)

1996-03-01

434

Calorimetric studies of quinoa ( Chenopodium quinoa Willd.) seed germination under saline stress conditions  

Microsoft Academic Search

Most crops in saline environments are negatively affected in their rate of growth. This effect is attributed either to osmotic causes or to ion toxicity depending on the plant species, salt composition and salt concentration. Species of the Chenopodiaceae family are considered to be resistant to this type of stress. Two cultivars of quinoa (Chenopodium quinoa Willd.), an ancestral crop

Fanny I. Schabes; E. Elizabeth Sigstad

2005-01-01

435

Calorimetric and computational study of 2- and 3-acetyl-1-methylpyrrole isomers.  

PubMed

This work reports the enthalpies of formation in the condensed and gas phases of 2-acetyl-1-methylpyrrole and 3-acetyl-1-methylpyrrole, derived from the standard (p(o) = 0.1 MPa) molar enthalpies of combustion, in oxygen, Delta(c)H(m)(o), measured by static bomb combustion calorimetry and the standard molar enthalpies of vaporization, Delta(l)(g)H(m)(o), at T = 298.15 K, obtained by high-temperature Calvet microcalorimetry. The theoretically estimated gas-phase enthalpies of formation were calculated from high-level ab initio molecular orbital calculations at the G3(MP2)//B3LYP level; the computed values compare very well with the experimental results obtained in this work and show that the 2-acetyl-1-methylpyrrole is thermodynamically more stable than the 3-isomer. Furthermore, this composite method was also applied in the calculation of bond dissociation enthalpies, gas-phase basicities, proton and electron affinities, and adiabatic ionization enthalpies. PMID:20141148

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

2010-03-01

436

Calorimetric studies of the heat capacity and relaxation of amorphous Si prepared by electron beam evaporation  

Microsoft Academic Search

The heat capacity of a-Si thin film prepared by electron beam evaporation method was measured from 360 to 820 K by a differential scanning calorimeter. For the as-prepared a-Si specimen, two novel irreversible endothermic processes and one irreversible broad exothermic reaction were found. The origins of the endothermic reactions were not known. It is suggested that they may be caused

K. H. Tsang; H. W. Kui; K. P. Chik

1993-01-01

437

Interaction of poly(L-arginine) with negatively charged DPPG membranes: calorimetric and monolayer studies.  

PubMed

The interaction of poly(L-arginine) (PLA) with dipalmitoyl-phosphatidylglycerol (DPPG) bilayer membranes and monolayers was studied by differential scanning calorimetry (DSC), isothermal titration calorimetry (ITC), and monolayer experiments. The binding of PLA affected the main transition temperature of lipid bilayers (T(m)) only marginally. Depending on the PLA chain length, T(m) was slightly increased or decreased. This finding was attributed to the superposition of two counteracting effects on the transition after PLA binding. The main transition enthalpy (DeltaH(m)) was decreased upon PLA binding and the formation of a ripple phase (P(beta)') was suppressed. ITC experiments showed that two distinct processes are involved in binding of PLA to gel phase (L(beta)') membranes. At low peptide content the binding reaction is endothermic, and at high peptide concentration the binding becomes exothermic. However, the enthalpy of binding to fluid (L(alpha)) membranes was exothermic for all peptide-to-lipid ratios. The temperature dependence of PLA binding to fluid palmitoyl-oleoyl-phosphatidylglycerol (POPG) membranes showed a decrease in binding enthalpy with increasing temperature (Delta(R)C(p) < 0), indicating hydrophobic contributions to the free energy of binding. For longer PLA chains, the binding enthalpy for L(alpha) membranes was more exothermic than for shorter chains. Monolayer adsorption experiments showed two consecutive binding processes. At low initial surface pressures (pi(0)) a condensation of the lipid film (Deltapi < 0) is first observed after PLA injection into the subphase, followed by an increase in film pressure (Deltapi > 0) due to insertion of peptide side chains into the monolayer. At higher pi(0) only an increase in film pressure can be observed due to the insertion of the side chains. Deltapi increases with increasing pi(0). The insertion of the peptide into the monolayer is corroborated by the observed shift of pi-A isotherms to higher molecular areas. All presented experiments show that the binding of PLA to DPPG membranes has not only electrostatic but also nonelectrostatic contributions. PMID:19603784

Schwieger, Christian; Blume, Alfred

2009-08-10

438

A scanning calorimetric study of unfolding equilibria in homodimeric chicken gizzard tropomyosins.  

PubMed Central

Using both circular dichroism (CD) and differential scanning calorimetry (DSC), several laboratories find that the thermal unfolding transitions of alpha alpha and beta beta homodimeric coiled coils of rabbit tropomyosin are multistate and display an overall unfolding enthalpy of near 300 kcal (mol dimer)(-1). In contrast, an extant CD study of beta beta and gamma gamma species of chicken gizzard tropomyosin concludes that their unfolding transitions are simple two-state transitions, with much smaller overall enthalpies (98 kcal mol(-1) for beta beta and 162 kcal mol(-1) for gamma gamma). However, these smaller enthalpies have been questioned, because they imply a concentration dependence of the melting temperatures that is far larger than observed by CD. We report here DSC studies of the unfolding of both beta beta and gamma gamma chicken gizzard homodimers. The results show that these transitions are very similar to those in rabbit tropomyosins in that 1) the overall unfolding enthalpy is near 300 kcal mol(-1); 2) the overall delta C(rho) values are significantly positive; 3) the various transitions are multistate, requiring at least two and as many as four domains to fit the DSC data. DSC studies are also reported on these homodimeric species of chicken gizzard tropomyosin with a single interchain disulfide cross-link. These results are also generally similar to those for the correspondingly cross-linked rabbit tropomyosins. PMID:9172766

O'Brien, R; Sturtevant, J M; Wrabl, J; Holtzer, M E; Holtzer, A

1996-01-01

439

Mechanisms of Organic-inorganic Interactions in Soils and Aqueous Environments Elucidated using Calorimetric Techniques  

E-print Network

pozzolanic product, the inhibition increased with NOM content. The effect of organic matter source followed the order fulvic acid> humic acid> lignite. Formation of CSH pozzolanic reaction products decreased by 50-100%, 20-80% and 20-40% in the presence...

Harvey, Omar R.

2011-08-08

440

Calorimetric and Resistive Measurements of Amorphous Splat Cooled La1-Xgax Foils  

E-print Network

epoxied to the substrate and silver painted to the heater and thermometer contacts. The mass of the epoxy and silver paint are less than 200 p,g. The other end of these leads is indi- um soldered to sapphire heat sinks, which in turn are indium... and compared to accepted values from the literature. The Au sample was a small piece of 0.05-in. wire which had been annealed at temperature near the melting point. The In sample was a foil rolled from indium wire and also annealed just below the melting...

SHULL, WH; Naugle, Donald G.; POON, SJ; JOHNSON, WL.

1978-01-01

441

Simultaneous measurement of specific heat and total hemispherical emissivity of metals by the transient calorimetric technique  

SciTech Connect

The specific heat c and total hemispherical emissivity {var_epsilon}{sub h} of iron and constantan have been measured using a simultaneous-measurement method proposed in a previous paper to verify the accuracy of the measurements. Cylindrical specimens, whose geometrical shape is presumed to be more appropriate than those in the previous study are used as the compound specimens necessary for the method. To obtain more accurate results, an expression for the temperature versus time curve has been developed; this expression is highly accurate over the entire temperature range. For iron, the measured c- and {var_epsilon}{sub h}-values are compared with c-values recommended in the CINDAS Data Series and with {var_epsilon}{sub h}-values previously measured by H. Masuda and M. Higano, respectively. For constantan, empirical relations between c and T (temperature) and {var_epsilon}{sub h} and T are obtained. Errors in the present results are analyzed and the total errors in the results are estimated.

Sasaki, Seizi; Masuda, Hidetoshi; Higano, Mitsuo; Sasaki, Hiroshi

1995-02-01

442

Thermochemistry of Bithiophenes and Thienyl Radicals. A Calorimetric and Computational Study  

NASA Astrophysics Data System (ADS)

The relative stabilities of 2,2'- and 3,3'-bithiophenes were evaluated by experimental thermochemistry and the results compared with data obtained from state of the art calculations, which were also extended to 2,3'-bithiophene. The standard (p° = 0.1 MPa) molar enthalpies of formation of crystalline 2,2'-bithiophene and 3,3'-bithiophene were calculated from the standard molar energies of combustion, in oxygen, to yield CO2 (g) and H2SO4·115H2O, measured by rotating-bomb combustion calorimetry at T = 298.15 K. The vapor pressures of these two compounds were measured as a function of temperature by Knudsen effusion mass-loss technique. The standard molar enthalpies of sublimation, at T = 298.15 K, were derived from the Clausius-Clapeyron equation. The experimental values were used to calculate the standard (p° = 0.1 MPa) enthalpies of formation of the title compounds in the gaseous phase; the results were analyzed and interpreted in terms of enthalpic increments and molecular structure. Standard ab initio molecular orbital calculations at the G3(MP2)//B3LYP level were performed. Enthalpies of formation, using homodesmotic reactions, were calculated and compared with experimental data. The computational study was also extended to the isomeric compound 2,3'-bithiophene. Detailed inspections of the molecular and electronic structures of the compounds studied were carried out. Finally, bond dissociation enthalpies (BDE) and enthalpies of formation of thienyl radicals were also computed.

Ribeiro da Silva, Manuel A. V.; Santos, Ana Filipa L. O. M.; Gomes, José R. B.; Roux, María Victoria; Temprado, Manuel; Jiménez, Pilar; Notario, Rafael

2009-09-01

443

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

Microsoft Academic Search

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

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

1994-01-01

444

Thermal properties of two titanium alloy dental implants — Linear behaviour and calorimetric analysis  

Microsoft Academic Search

The purpose of the study is to investigate several thermal properties of two metallic materials based on titanium (Ti6Al4V and Ti10Mo) used in the fabrication of dental implants. Materials and methods: the laboratory equipment on which the tests were performed is a horizontal dilatometer type L75HS. The experiment was conducted on cylindrical samples of implant alloy type Ti6Al4V and on

Norina Forna; Nicanor Cimpoesu; Maricel Agop; Cristina Iordache; Doriana Forna; Constanta Mocanu

2011-01-01

445

Structural and calorimetrical studies of the effect of different aminoglycosides on DPPC liposomes.  

PubMed

The effects of tobramycin, spectinomycin and streptomycin on 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/water vesicle system were studied by using differential scanning calorimetry (DSC) and simultaneous small- and wide-angle X-ray scattering (SWAXS) in the 0-1 lipid/aminoglycoside molar range. The changes in enthalpy between the thermally adjacent phases are decreased, but the pace of decrease is totally different for the three investigated AGs. The alterations in the lamellar arrangement and the chain packing are rather tendentious and are extended by increased AG concentrations depending on the type of the AG. In the case of tobramycin and streptomycin, still sharp Bragg peaks of SAXS curves shift to smaller values of the scattering variable, while spectinomycin results in an entire loss of multilayer correlation representing an increased amount of unbound bilayers. PMID:19118988

Oszlánczi, Agnes; Bóta, Attila; Czabai, Gábor; Klumpp, Erwin

2009-02-15

446

Calorimetric studies of lipid tubule formation from ethanol-water solutions.  

PubMed

We have used differential scanning calorimetry to systematically investigate the thermal formation of hollow cylindrical crystalline microstructures or 'tubules' upon cooling a diacetylenic phosphatidylcholine (1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine) dispersed in varying volume fractions of ethanol/water. Tubule formation is characterized by a large exothermic event, observed upon cooling the lipid in 60-80% ethanol. The enthalpy of the transition was observed to be highest in this window of tubule formation (128-138 J/g) which is significantly higher than previously reported values for the enthalpy of tubule formation in water (90 -95 J/g). The enthalpy associated with the formation of tubules in 70% ethanol was also found to be strongly dependent on the efficiency of tubule formation and decreased as the number density of tubules decreased. A significant decrease in tubule number density could be brought about by increasing the lipid concentration of the 70% ethanol solution. Tubule number density was maximized at lipid concentrations between 0.5 and 2 mg/ml in 70% ethanol. Examination of the C-H stretch region from infrared spectra of the lipid below the phase transition, indicate that the intramolecular chain order-disorder is similar, regardless of the fraction of ethanol. The higher transition enthalpy for the melting of tubules in 60-80% ethanol (compared to water) implies that the high-temperature phase from which the tubules form in ethanol is more disordered than the lamellar liquid crystalline phase from which tubules form in water. PMID:1643105

Rudolph, A S; Testoff, M A; Shashidar, R

1992-07-29

447

Calorimetric studies of amphiphile/oil/water systems for enhanced oil recovery  

SciTech Connect

Better experimental methods and new types of data are needed for the measurement and prediction of the phase behavior of amphiphile/oil/water systems used in various types of enhanced oil recovery (EOR), including both dispersion-based mobility control for ''gas'' flooding (emulsions and foams), and high-capillary number EOR. This paper reports progress in the use of titration calorimetry (both isoperibolic and isothermal) for the measurement of phase diagrams of cosurfactant/n-alkane/water systems. The cosurfactants studied included alcohols and low molecular weight ethoxylated alcohols. Compositions of triconjugate (lower-, middle-, upper-phase systems) were obtained without conventional compositional analyses by thermal detection of compositions at which the number of phases changed from two to three, linear regressions to get the limiting tielines, and calculation of the tietriangle corners from the interceptions of the equations for the limiting tielines. The first measurements of the heats of formation of triconjugate phases in these types of systems are also reported.

Dunn, R.O.; Das, K.; Covatch, G.; Smith, D.H.

1988-05-01

448

Determining a carbohydrate profile for Hansenula polymorpha  

NASA Technical Reports Server (NTRS)

The determination of the levels of carbohydrates in the yeast Hansenula polymorpha required the development of new analytical procedures. Existing fractionation and analytical methods were adapted to deal with the problems involved with the lysis of whole cells. Using these new procedures, the complete carbohydrate profiles of H. polymorpha and selected mutant strains were determined and shown to correlate favourably with previously published results.

Petersen, G. R.

1985-01-01

449

On the determination of meteoroid orbital elements  

Microsoft Academic Search

The classical method of the determination of the orbital elements of meteoroids is based on a sequence of corrections applied to the velocity vector of an observed meteor. The main aim of such an approach is the determination of the meteoroid's motion under the gravitational influence of the Sun but we are able to observe this motion only under the

P. Pecina

1994-01-01

450

Newcastle disease virus vaccine potency determination  

Technology Transfer Automated Retrieval System (TEKTRAN)

Potency of inactivated Newcastle disease virus (NDV) vaccines is determined using vaccination and challenge. If the minimum killed viral antigen necessary for clinical protection can be determined, vaccines meeting or exceeding this dose might be considered of adequate potency. In these studies, c...

451

The determinants of the antibiotic resistance process  

PubMed Central

Background: The use of antibiotic drugs triggers a complex interaction involving many biological, sociological, and psychological determinants. Resistance to antibiotics is a serious worldwide problem which is increasing and has implications for morbidity, mortality, and health care both in hospitals and in the community. Objectives: To analyze current research on the determinants of antibiotic resistance and comprehensively review the main factors in the process of resistance in order to aid our understanding and assessment of this problem. Methods: We conducted a MedLine search using the key words “determinants”, “antibiotic”, and “antibiotic resistance” to identify publications between 1995 and 2007 on the determinants of antibiotic resistance. Publications that did not address the determinants of antibiotic resistance were excluded. Results: The process and determinants of antibiotic resistance are described, beginning with the development of antibiotics, resistance and the mechanisms of resistance, sociocultural determinants of resistance, the consequences of antibiotic resistance, and alternative measures proposed to combat antibiotic resistance. Conclusions: Analysis of the published literature identified the main determinants of antibiotic resistance as irrational use of antibiotics in humans and animal species, insufficient patient education when antibiotics are prescribed, lack of guidelines for treatment and control of infections, lack of scientific information for physicians on the rational use of antibiotics, and lack of official government policy on the rational use of antibiotics in public and private hospitals. PMID:21694883

Franco, Beatriz Espinosa; Altagracia Martínez, Marina; Sánchez Rodríguez, Martha A; Wertheimer, Albert I

2009-01-01

452

CONTINGENCY DESIGNS FOR ATTITUDE DETERMINATION OF TRMM  

E-print Network

, a contingency mode is used to allow for the continuation of the scientific mission. Attitude determination1 CONTINGENCY DESIGNS FOR ATTITUDE DETERMINATION OF TRMM John L. Crassidis, Stephen F. Andrews, F Corporation Greenbelt, MD 20770 Abstract In this paper, several attitude estimation designs are developed

Crassidis, John L.

453

Determinants of customer satisfaction in retail banking  

Microsoft Academic Search

Points out that customer satisfaction and retention are critical for retail banks, and investigates the major determinants of customer satisfaction and future intentions in the retail bank sector. Identifies the determinants which include service quality dimensions (e.g. getting it right the first time), service features (e.g. competitive interest rates), service problems, service recovery and products used. Finds, in particular, that

Terrence Levesque; Gordon H. G. McDougall

1996-01-01

454

Temperature-Dependent Sex Determination in Turtles  

Microsoft Academic Search

The sex of hatchling map turtles is determined by incubation temperature of eggs in the laboratory as well as in nature. Temperature controls sex differentiation rather than causing a differential mortality of sexes. Temperature has no effect on sex determination in a soft-shelled turtle.

J. J. Bull; R. C. Vogt

1979-01-01

455

Wage Determination and Discrimination among Older Workers.  

ERIC Educational Resources Information Center

Analyzed determinants of wage rates of older workers and the large discrepancies existing between wage earned by Whites, non-Whites, men, and women. Human capital and geographic variables were important wage determinants. Differences in variables cannot completely explain the wage differentials of race and sex. (Author)

Quinn, Joseph F.

1979-01-01

456

THE SPECTROPHOTOMETRIC DETERMINATION OF URANIUM WITH DIBENZOYLMETHANE  

Microsoft Academic Search

Description is given of a simple direct spectrophotometric determination ; of uranium with dibenzoylmethane in combination with tributyl phosphate, which is ; selected as the extractant of uranium because of its popularity. The procedure ; was applied to the determination of U in U ores and in monazite. One advantage ; of the method is that change in acidity does

Yoshimi Umezaki

1963-01-01

457

Determinants of Economic Growth: Will Data Tell?  

Microsoft Academic Search

Many factors inhibiting and facilitating economic growth have been suggested. Will international income data tell which matter when all are treated symmetrically a priori? We find that growth determinants emerging from agnostic Bayesian model averaging and classical model selection procedures are sensitive to income differences across datasets. For example, many of the 1975-1996 growth determinants according to World Bank income

Antonio Ciccone; Marek Jarocinski

2007-01-01

458

Dominance Affects Determiner Selection in Language Production  

ERIC Educational Resources Information Center

Janssen and Caramazza (2003) show that when producing diminutives or plurals in Dutch, determiner information about the corresponding (singular) base form is active. This is reflected in a time cost for producing the plural or the diminutive with a gender-marked determiner when these forms and the corresponding singular or base form require…

Spalek, K.; Schriefers, H.J.

2005-01-01

459

Determination of Movement Sense in Mylonites.  

ERIC Educational Resources Information Center

Describes how mylonite samples can be used to determine the sense of shear. Several sample collection techniques are presented. Criteria for shear sense determination are outlined and discussed so that they can be recognized and interpreted by students familiar with the use of a compass and a petrographic microscope. (TW)

Simpson, Carol

1986-01-01

460

TLC determination of functionality in prepolymers  

NASA Technical Reports Server (NTRS)

Application of thin-layer chromatographics provides rapid qualitative determination of functional distribution in experimental prepolymer. Functionality distribution is of fundamental importance for it determines; (1) manner in which given carboxyl-terminated prepolymer will cure and (2) physical properties of resulting product.

Potts, J. E., Jr.; Ashcraft, A. C.

1973-01-01

461

Determinants and impact of sovereign credit ratings  

Microsoft Academic Search

The authors conduct the first systematic analysis of the determinants and impact of the sovereign credit ratings assigned by the two leading U.S. agencies, Moody's Investor Services and Standard and Poor's. Of the large number of criteria used by the two agencies, six factors appear to play an important role in determining a country's credit rating: per capita income, GDP

Richard Cantor; Frank Packer

1996-01-01

462

The Determinants of Credit Spread Changes  

Microsoft Academic Search

Using dealer's quotes and transactions prices on straight industrial bonds, we investigate the determinants of credit spread changes. Variables that should in theory determine credit spread changes have rather limited explanatory power. Further, the residuals from this regression are highly cross-correlated, and principal components analysis implies they are mostly driven by a single common factor. Although we consider several macroeconomic

Pierre Collin-Dufresne; Robert S. Goldstein; J. Spencer Martin

2001-01-01

463

Determinants of Success during Triathalon Competition.  

ERIC Educational Resources Information Center

Eleven male triathletes were studied to determine the relationships between selected metabolic measurements and triathalon performance. Oxygen uptake, pulmonary ventilation, and heart rate were measured during freestyle swimming, cycling, and treadmill running. Economy of effort was an important determinant of performance. (JD)

Dengel, Donald R.; And Others

1989-01-01

464

45 CFR 12a.4 - Suitability determination.  

...OF FEDERAL REAL PROPERTY TO ASSIST THE HOMELESS § 12a.4 Suitability determination...suitable for use as facilities to assist the homeless and report its determination...property for use as a facility to assist the homeless without regard to any particular...

2014-10-01

465

PRECONCENTRATION METHODS FOR TRACE ELEMENT DETERMINATION  

EPA Science Inventory

This research had several objectives. One was to review the literature to determine methods of trace element preconcentration that could be used realistically for sample preparation for trace element determinations in drinking, natural and/or effluent waters. Elements included in...

466

ZWY Sex Determination in Xenopus tropicalis  

EPA Science Inventory

Most vertebrate species with described genetic sex determination are either male (XY) or female (ZW) heterogametic. To date, studies with Xenopus species indicate that members of this genus operate under a ZW sex determination system. We used two different approaches and demonst...

467

Determining Enzyme Activity by Radial Diffusion  

ERIC Educational Resources Information Center

Discusses advantages of radial diffusion assay in determining presence of enzyme and/or rough approximation of amount of enzyme activities. Procedures are included for the preparation of starch-agar plates, and the application and determination of enzyme. Techniques using plant materials (homogenates, tissues, ungerminated embryos, and seedlings)…

Davis, Bill D.

1977-01-01

468

REPRODUCTIONEDITORIAL Focus on determinants of male fertility  

E-print Network

in vitro (e.g. by in vitro fertilization) or in vivo (e.g. by artificial insemination). The latterREPRODUCTIONEDITORIAL Focus on determinants of male fertility E R S Roldan Reproductive Ecology the main determinants of male fertility would allow us to advance our knowledge of male reproductive

Museo Nacional de Ciencias Naturales

469

Framing the Future: Self-Determination  

ERIC Educational Resources Information Center

There is an established and still-growing evidence base that promoting self-determination has positive school and post-school benefits for students with disabilities, and yet efforts to do so remain sporadic, at best. This article examines the evidence that promoting self-determination is critically important for students with disabilities,…

Wehmeyer, Michael L.

2015-01-01

470

Psychosocial Determinants of Childhood and Adolescent Obesity  

Microsoft Academic Search

The purpose of this article was to identify psychosocial determinants of childhood and adolescent obesity. Some of the determinants were considered non-modifiable such as genetics, sex, age, and race. The risk of developing obesity started early on in life, with high birth weight, rapid growth in infancy, maternal smoking during pregnancy, and lack of breastfeeding indicated as positive predictors. Family

Manoj Sharma; Melinda J. Ickes

2008-01-01

471

7 CFR 51.1416 - Optional determinations.  

Code of Federal Regulations, 2010 CFR

...States Standards for Grades of Pecans in the Shell 1 Optional Determinations § 51.1416...minimum sample of at least 500 grams of in-shell pecans shall be used for determination...pieces of kernels shall be separated from shells, center wall, and other...

2010-01-01

472

Climate, Deer, Rodents, and Acorns as Determinants  

E-print Network

Climate, Deer, Rodents, and Acorns as Determinants of Variation in Lyme-Disease Risk Richard S the determinants of Lyme-disease risk (density and Borrelia burgdorferi-infection prevalence of nymphal Ixodes Lyme disease (Dutchess County, New York). We used a model comparison approach to simultaneously test

473

Laurent Determinants and Arrangements of Hyperplane Amoebas  

Microsoft Academic Search

We study amoebas associated with Laurent polynomials and obtain new results regarding the number and structure of the connected components of the complement of the amoeba. We also investigate the associated Laurent determinant. In the case of a hyperplane arrangement we perform explicit computations leading to a closed formula for the Laurent determinant.

Mikael Forsberg; Mikael Passare

2000-01-01

474

Determination Of Ph Including Hemoglobin Correction  

DOEpatents

Methods and apparatuses of determining the pH of a sample. A method can comprise determining an infrared spectrum of the sample, and determining the hemoglobin concentration of the sample. The hemoglobin concentration and the infrared spectrum can then be used to determine the pH of the sample. In some embodiments, the hemoglobin concentration can be used to select an model relating infrared spectra to pH that is applicable at the determined hemoglobin concentration. In other embodiments, a model relating hemoglobin concentration and infrared spectra to pH can be used. An apparatus according to the present invention can comprise an illumination system, adapted to supply radiation to a sample; a collection system, adapted to collect radiation expressed from the sample responsive to the incident radiation; and an analysis system, adapted to relate information about the incident radiation, the expressed radiation, and the hemoglobin concentration of the sample to pH.

Maynard, John D. (Albuquerque, NM); Hendee, Shonn P. (Albuquerque, NM); Rohrscheib, Mark R. (Albuquerque, NM); Nunez, David (Albuquerque, NM); Alam, M. Kathleen (Cedar Crest, NM); Franke, James E. (Franklin, TN); Kemeny, Gabor J. (Madison, WI)

2005-09-13

475

Photometric determination of traces of metals  

SciTech Connect

The first three editions of this widely used classic were published under the title Colorimetric Determination of Traces of Metals, with E.B. Sandell as author. Part I (General Aspects) of the fourth edition was co-authored by E.B. Sandell and H. Onishi and published in 1978. After Sandell's death in 1984, Onishi assumed the monumental task of revising Part II. This book (Part IIA) consists of 21 chapters in which the photometric determinations of the individual metals, aluminium to lithium (including the lanthanoids), are described. Each chapter is divided into three sections: Separations, Methods of Determination, and Applications. The sections on Separations are of general interest and include methods based on precipitation, ion-exchange, chromatography, and liquid-liquid extraction. Molecular absorption and fluorescence techniques are described in the sections on determinations, and the emphasis is on the use of well-established reagents. Several reagents that have been recently introduced for the determination of trace levels of metals are also critically reviewed at the end of each section on methods of determination. Important applications of these methods to the determination of trace metals in complex organic and inorganic materials are described in detail at the end of each chapter.

Onishi, H.

1986-01-01

476

Genetics of sex determination in tilapiine species.  

PubMed

We identified DNA markers linked to sex determining genes in six closely related species of tilapiine fishes. The mode of sex determination differed among species. In Oreochromis karongae and Tilapia mariae the sex-determining locus is on linkage group (LG) 3 and the female is heterogametic (WZ-ZZ system). In O. niloticus and T. zillii the sex-determining locus is on LG1 and the male is heterogametic (XX-XY system). A more complex pattern was observed in O. aureus and O. mossambicus, in which markers on both LG1 and LG3 were associated with sex. We found evidence for sex-linked lethal effects on LG1, as well as interactions between loci in the two linkage groups. Comparison of genetic and physical maps demonstrated a broad region of recombination suppression harboring the sex-determining locus on LG3. Sex-specific recombination suppression was found in the female heterogametic sex. Sequence analysis showed the accumulation of repetitive elements in this region. Phylogenetic analysis suggests that at least two transitions in the mode of sex determination have occurred in this clade. This variation in sex determination mechanisms among closely related species makes tilapias an excellent model system for studying the evolution of sex chromosomes in vertebrates. PMID:18418034

Cnaani, A; Lee, B-Y; Zilberman, N; Ozouf-Costaz, C; Hulata, G; Ron, M; D'Hont, A; Baroiller, J-F; D'Cotta, H; Penman, D J; Tomasino, E; Coutanceau, J-P; Pepey, E; Shirak, A; Kocher, T D

2008-01-01

477

The Fredholm Determinant for a Dirac Operator  

NASA Astrophysics Data System (ADS)

The Fredholm determinant for a Dirac operator appropriate to a particle moving in one spatial dimension is investigated. The operator is written as H = px? 1 + m? 3 + V( x), where px, m, and V( x) are, respectively, the momentum, mass, and potential energy of the particle and the Pauli spin matrices, ? i, constitute a representation of the Dirac matrices. With H0 = px? 1 + m? 3 and z a complex number, the Fredholm determinant is denoted by Det[( z- H)/( z- H0)]. Let M( x) be the 2 × 2 matrix that transfers a spinor solution, ?( x), of the Dirac equation H?( x) = z?( x) from - L to x:?( x) = M( x)?(- L) and let M0( x) be the corresponding matrix for H0. Then it is shown, for eigenfunctions obeying the periodic boundary condition ?( L) = ?(- L), that Det[( z- H)/( z- H0] equals the determinant of the 2 × 2 matrix [1- M( L)]/[1- M0( L)]. The calculation of an infinite determinant is thus reduced to the calculation of a 2 × 2 determinant and for piecewise constant potentials an expression for Det[( z- H)/( z- H0)] may be derived in closed form. The relation between the Fredholm determinant and the finite determinant was conjectured in an earlier work by D. Waxman and K. D. Ivanova-Moser, Ann. Phys.226 (1993), 271.

Waxman, D.

1994-05-01

478

The Molecular Basis Of Male Sex Determination During Temperature-Dependent Sex Determination.  

E-print Network

??The red-eared slider turtle (Trachemys scripta) possesses temperature-dependent sex determination (TSD) in which the incubation temperature of the developing embryo determines gonadal sex. Although a… (more)

Bieser, Kayla

2013-01-01

479

78 FR 48191 - Certain Linear Actuators; Commission Determination Not To Review an Initial Determination...  

Federal Register 2010, 2011, 2012, 2013

...COMMISSION Investigation No. 337-TA-880 Certain Linear Actuators; Commission Determination Not To Review an Initial Determination...within the United States after importation of certain linear actuators by reason of infringement of U.S. Patent No...

2013-08-07

480

Joint torsion equals the determinant invariant.  

E-print Network

A determinant in algebraic $K$-theory is associated to any two almost commuting Fredholm operators. On the other hand, one can calculate a homologically defined invariant known as joint torsion. We answer in the affirmative a conjecture of Richard Carey and Joel Pincus, namely that these two invariants agree. In particular, this implies that joint torsion is norm continuous, depends only on the images of the operators modulo trace class, and satisfies the expected Steinberg relations. Moreover, we show that the determinant invariant of two commuting operators can be computed simply as a determinant on a finite dimensional vector space.

Joseph Migler