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1

Calorimetric Studies on Sulphur Containing Compounds.  

National Technical Information Service (NTIS)

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

M. Safdar

1984-01-01

2

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

National Technical Information Service (NTIS)

Three precise calorimetric methods, viz., low-temperature adiabatic, high-temperatuare drop, and solution-reaction, have been used to determine as a function of temperature the key chemical thermodynamic properties of a pure sample of schoepite, UO sub 2 ...

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

1987-01-01

3

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

SciTech Connect

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

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

1987-08-01

4

Calorimetric Study of the Intermetallic Compounds Ual sub 2 and Pual sub 2 .  

National Technical Information Service (NTIS)

Results of low temperature specific heat measurements are presented on the strongly paramagnetic intermetallic compounds UAl sub 2 and PuAl sub 2 in the temperature intervals 0.9 to 20 exp 0 K, respectively. These compounds are characterized by very narro...

R. J. Trainor M. B. Brodsky G. S. Knapp

1975-01-01

5

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

Microsoft Academic Search

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

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

1999-01-01

6

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

7

Flow calorimetric and thermal gravimetric study of adsorption of thiophenic sulfur compounds on NaY zeolite  

Microsoft Academic Search

A study of adsorption of thiophenic sulfur compounds (thiophene, benzothiophene, dibenzothiophene and 4,6-dimethyl benzothiophene) in normal alkane solvents (octane, dodecane and hexadecane) on NaY zeolite has been performed by using flow calorimetry technique and thermogravimetric analysis. The measured heat of adsorption of sulfur compounds includes the heat from the displacement of the adsorbed solvent molecules by sulfur compounds and it

Ming Jiang; Flora T. T. Ng; Ataur Rahman; Viral Patel

2005-01-01

8

Electronic calorimetric computer  

NASA Technical Reports Server (NTRS)

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

Heckelman, J. D.

1968-01-01

9

Calorimetric gas sensor  

DOEpatents

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

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

1998-01-01

10

Calorimetric gas sensor  

DOEpatents

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

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

1998-11-10

11

Inhibition of collagen XVI expression reduces glioma cell invasiveness.  

PubMed

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

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

2011-01-01

12

EDITORIAL: XVI Brazilian Colloquium on Orbital Dynamics  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

13

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2010 CFR

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

2009-04-01

14

25 CFR 36.43 - Standard XVI-Student activities.  

Code of Federal Regulations, 2010 CFR

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

2010-04-01

15

Thermodynamic properties by non-calorimetric methods. Final report  

SciTech Connect

This research program provided a valuable complement to the experimental programs currently in progress at NIPER for the Advanced Research and Technology Development (AR and TD) and Advanced Exploration and Process Technology (AEPT) divisions of the Department of Energy. These experimental programs are focused on the calorimetric determination of thermodynamic properties of key polynuclear heteroatom-containing aromatic molecules. The project for the Office of Energy Research focused on the non-calorimetric determination of thermodynamic properties through the extension of existing correlation methodologies and through molecular spectroscopy with statistical mechanics. The paper discusses the following studies: Group-contribution approach for polycyclic aromatic hydrocarbons (naphthalene, phenanthrene, anthracene, pyrene, 3-methylphenanthrene, benzoquinolines, biphenyl/hydrogen system); Group-contribution approach for key monocyclic organic compounds; Molecular spectroscopy and statistical mechanics; and Thermophysical property correlations.

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

1992-12-31

16

Calorimetric Investigation of Deuterated Palladium Electrodes.  

National Technical Information Service (NTIS)

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

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

1991-01-01

17

Calorimetric analysis of the plasma proteome.  

PubMed

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

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

2007-11-01

18

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

19

Calorimetric equipment for measuring magnetic losses  

Microsoft Academic Search

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

V. V. Kogen-Dalin; Khusein Nigm

1965-01-01

20

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

Federal Register 2010, 2011, 2012, 2013

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

2011-07-28

21

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

Federal Register 2010, 2011, 2012, 2013

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

2013-02-20

22

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

SciTech Connect

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

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

1999-04-05

23

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

24

Unilateral NMR study of a XVI century wall painted.  

PubMed

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

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

2007-06-01

25

Radiation beam calorimetric power measurement system  

DOEpatents

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

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

1992-01-01

26

Nanowell-patterned TiO2 microcantilevers for calorimetric chemical sensing  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

27

A reaction calorimetric investigation of the hydrogenation of a substituted pyrazine  

SciTech Connect

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

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

1995-11-01

28

Compound  

NASA Astrophysics Data System (ADS)

We have prepared Ce-doped polycrystalline AgSbTe2.01 compounds from high-purity elements by a melt-quench technique followed by spark plasma sintering, and their thermoelectric transport properties have been investigated in the temperature range of 300 K to 625 K. The actual concentration of Ce was much less than the initial composition, but roughly proportional to it. Small additions of Ce shifted the composition of the homogeneity range from the nearly ideal atomic ratio Ag:Sb:Te = 0.98:1.02:2.01 toward Sb rich (Ag poor), and led to the reemergence of Ag2Te impurity in AgSbTe2 compound. The Ce-doped samples possessed lower electrical conductivity compared with the undoped AgSbTe2.01 compound at room temperature, but the carrier mobility and effective mass were essentially constant, indicating intact band structure near the covalent band maximum upon Ce substitution for Sb. Due to the decrease of lattice vibration anharmonicity resulting from Ce substitution for Sb, the lattice conductivity of the Ce-doped samples was about 0.1 W m-1 K-1 higher than that of the AgSbTe2.01 sample, and the magnitude spanned the range from 0.30 W m-1 K-1 to 0.55 W m-1 K-1. A ZT of 1.20 was achieved at about 615 K for the AgSb0.99Ce0.01Te2.01 sample.

Du, B.; Li, H.; Tang, X.

2014-06-01

29

Compound  

NASA Astrophysics Data System (ADS)

Recently, Cu-based chalcogenides such as Cu3SbSe4, Cu2Se, and Cu2SnSe3 have attracted much attention because of their high thermoelectric performance and their common feature of very low thermal conductivity. However, for practical use, materials without toxic elements such as selenium are preferable. In this paper, we report Se-free Cu3SbS4 thermoelectric material and improvement of its figure of merit ( ZT) by chemical substitutions. Substitutions of 3 at.% Ag for Cu and 2 at.% Ge for Sb lead to significant reductions in the thermal conductivity by 37% and 22%, respectively. These substitutions do not sacrifice the power factor, thus resulting in enhancement of the ZT value. The sensitivity of the thermal conductivity to chemical substitutions in these compounds is discussed in terms of the calculated phonon dispersion and previously proposed models for Cu-based chalcogenides. To improve the power factor, we optimize the hole carrier concentration by substitution of Ge for Sb, achieving a power factor of 16 ?W/cm K2 at 573 K, which is better than the best reported for Se-based Cu3SbSe4 compounds.

Suzumura, Akitoshi; Watanabe, Masaki; Nagasako, Naoyuki; Asahi, Ryoji

2014-06-01

30

Calorimetric study of aligned liquid crystal + aerosil  

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

31

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

SciTech Connect

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

Kabadi, V.N.

1990-01-01

32

Molecular energetics of alkyl pyrrolecarboxylates: calorimetric and computational study.  

PubMed

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

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

2013-06-20

33

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

34

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

SciTech Connect

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

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

2012-10-01

35

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

NASA Astrophysics Data System (ADS)

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

Weisberg, Joel M.; Paglen, Trevor

2012-10-01

36

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

Microsoft Academic Search

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

Donald K. Grayson; Françoise Delpech

2003-01-01

37

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

SciTech Connect

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

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

1989-12-31

38

Calorimetric Method of Sensitivity Calibration for Far-Infrared Detectors.  

National Technical Information Service (NTIS)

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

M. Daehler

1976-01-01

39

Determination of the calorimetric energy in extensive air showers  

Microsoft Academic Search

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

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

2004-01-01

40

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

SciTech Connect

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

Kabadi, V.N.

1989-01-01

41

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

Federal Register 2010, 2011, 2012, 2013

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

2013-02-12

42

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

Code of Federal Regulations, 2013 CFR

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

2013-04-01

43

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

44

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

SciTech Connect

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

Kabadi, V.N.

1991-01-01

45

A calorimetric system for metabolic studies of newborn babies.  

PubMed

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

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

1985-02-01

46

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

Microsoft Academic Search

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

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

1997-01-01

47

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

Microsoft Academic Search

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

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

2002-01-01

48

ELECTROCHEMICAL CALORIMETRIC STUDIES OF THE COLD FUSION EFFECT  

Microsoft Academic Search

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

M. H. Miles; D. E. Stilwell

49

Energy associated with dislocations: A calorimetric study using synthetic quartz  

Microsoft Academic Search

High temperature oxide melt solution calorimetry was used to study the energy associated with dislocations in quartz by comparing undeformed and deformed single crystals of synthetic quartz. Samples were deformed at 698 K, 1000–1500 MPa at a strain rate of 10-5 sec-1. Two sets of calorimetric measurements were made: (i) using a Pt capsule as a container for powdered sample,

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

1995-01-01

50

A Calorimetric Micro-Sensor for Methane Detection  

Microsoft Academic Search

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

Sebastian Sosin; Carmen Moldovan; Elena Manea

51

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

NASA Astrophysics Data System (ADS)

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

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

2007-06-01

52

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

NASA Astrophysics Data System (ADS)

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

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

2007-04-01

53

Polynitroaliphatic explosives containing the pentafluorosulfanyl (SF5) group: The selection and study of a model compound  

Microsoft Academic Search

An investigation concerning the effect of the pentafluoro-sulfanyl (SF5) group on the properties of explosive nitro compounds is described. The investigation includes: (a) the preparation of several polynitro SF5 model compounds; (b) the selection of the best model compound (based on overall properties such as melting point, stability, ease of synthesis, etc.); (c) the subjection of this compound to calorimetric

M. E. Sitzmann; W. H. Gilligan; D. L. Ornellas; J. S. Thrasher

1990-01-01

54

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

NASA Astrophysics Data System (ADS)

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

Beiersdorfer, P.; Diaz, F.; Ishikawa, Y.

2012-02-01

55

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

56

A no-calorimetric method for measuring SAR in MRI  

NASA Astrophysics Data System (ADS)

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

Romano, Rocco; Acernese, Fausto; Barone, Fabrizio

2011-03-01

57

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

58

Calorimetric studies of curium complexation. 2. Amino carboxylates  

SciTech Connect

Calorimetric titrations using the long-lived isotope of curium (curium-248) have been conducted with nitrilotriacetate, trans-1,2-cyclohexanedinitrilotetraacetate, and trimethylenedinitrilotetraacetate. The data plus the stability constants measured previously allowed calculations of the thermodynamic parameters of the 1:1 complexation. Similar titrations were conducted with europium to provide comparison of the lanthanide and actinide trivalent ion behaviors. The enthalpy values for the amino polycarboxylate complexing of Cm(III) are greater than those for Eu(III). However, the entropy values for the complexing of both cations are similar. These results are comparable to the previously reported data for EDTA. 13 references, 2 figures, 3 tables.

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

1987-07-15

59

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

60

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

PubMed

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

Davaji, Benyamin; Lee, Chung Hoon

2014-09-15

61

Empirical free energy calculation: comparison to calorimetric data.  

PubMed Central

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

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

1997-01-01

62

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

Microsoft Academic Search

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

Enric Aragonès i Valls

2007-01-01

63

Determination of the calorimetric energy in extensive air showers  

NASA Astrophysics Data System (ADS)

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

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

2004-11-01

64

Synthesis of nitrate sodalite: An in situ scanning calorimetric study  

NASA Astrophysics Data System (ADS)

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

Liu, Qingyuan; Navrotsky, Alexandra

2007-04-01

65

ac-Calorimetric Measurements of Transverse Thermal Conductivity  

NASA Astrophysics Data System (ADS)

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

Zhang, Hao; Brill, Joseph

2013-03-01

66

Calorimetric measurement and modelling of the equivalent series of capacitors  

NASA Astrophysics Data System (ADS)

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

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

1999-12-01

67

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

68

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

69

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

SciTech Connect

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

Kabadi, V.N.

1991-01-01

70

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

71

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

National Technical Information Service (NTIS)

This paper presents a calorimetric measurement of layer-specific inward-flowing fractions of absorbed solar energy for a number of geometric configurations common in fenestrations with shading. The inward-flowing fractions are found to be relatively insen...

J. H. Klems G. O. Kelley

1995-01-01

72

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

NASA Astrophysics Data System (ADS)

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

de Rújula, A.; Lusignoli, M.

1982-12-01

73

Optical Absorptance and Thermomodulation Studies of Several A-15 Compounds.  

National Technical Information Service (NTIS)

The purpose of this work was to investigate the optical properties of several high T/sub c/ compounds in the form of sputtered films. The measurements are used toward this end: optical absorptance (using a calorimetric technique near 4.2K), which yields (...

R. C. McKee

1983-01-01

74

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

75

Calorimetric and relaxation properties of xylitol-water mixtures  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

76

Adiabatic Heat of Hydration Calorimetric Measurements for Reference Saltstone Waste  

SciTech Connect

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

Bollinger, James

2006-01-12

77

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

78

Laser calorimetric absorptance testing of samples with varying geometry  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

79

Neutron induced capture and fission discrimination using calorimetric shape decomposition  

NASA Astrophysics Data System (ADS)

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

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

80

Calorimetric analysis of gelatine-glycosaminoglycans blend system.  

PubMed

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

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

2011-10-01

81

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

PubMed

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

Pinto, Susana S; Diogo, Hermínio P

2008-12-01

82

Differential scanning calorimetric studies of nickel titanium rotary endodontic instruments.  

PubMed

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

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

2002-08-01

83

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

PubMed

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

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

2013-03-10

84

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.

85

Thermodynamic properties of chlorite and berthierine derived from calorimetric measurements  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

86

Neutron detection by measuring capture gammas in a calorimetric approach  

NASA Astrophysics Data System (ADS)

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

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

2011-10-01

87

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

NASA Astrophysics Data System (ADS)

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

Uchida, Takeyoshi; Kikuchi, Tsuneo

2013-07-01

88

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

Microsoft Academic Search

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

Mieko Kumasaki; Yasuhiro Fujimoto; Takayuki Ando

2003-01-01

89

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

National Technical Information Service (NTIS)

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

D. C. Hopkins

1968-01-01

90

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

Microsoft Academic Search

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

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

2006-01-01

91

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

Microsoft Academic Search

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

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

1997-01-01

92

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

Microsoft Academic Search

Several calorimetric measurements on electrolysis processes for monitoring the ‘‘cold fusion’’ event are represented in this work. A Calvet microcalorimeter with its auxiliaries such as amplifier, recorder, computer etc. was used here for measuring the output power generated during these processes. And at the same time, the total electric input power was recorded for comparing with differences between the out

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

1991-01-01

93

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

Microsoft Academic Search

Several calorimetric measurements on electrolysis processes for monitoring the ``cold fusion'' event are represented in this work. A Calvet microcalorimeter with its auxiliaries such as amplifier, recorder, computer etc. was used here for measuring the output power generated during these processes. And at the same time, the total electric input power was recorded for comparing with differences between the out

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

1991-01-01

94

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

Microsoft Academic Search

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

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

2009-01-01

95

Differential scanning calorimetric analysis for monitoring the oxidation of heated oils  

Microsoft Academic Search

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

C. P Tan; Y. B Che Man

1999-01-01

96

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

Microsoft Academic Search

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

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

1979-01-01

97

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

Microsoft Academic Search

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

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

2010-01-01

98

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

National Technical Information Service (NTIS)

The work on this project was initiated on September 1, 1989. The project consisted of three different tasks. 1. A thermodynamic model to predict VLE and calorimetric properties of coal liquids. 2. VLE measurements at high temperature and high pressure for...

V. N. Kabadi

1992-01-01

99

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

Microsoft Academic Search

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

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

1991-01-01

100

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

PubMed

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

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

1990-12-01

101

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

Microsoft Academic Search

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

S. Sosin; C. Moldovan; R. Iosub

2004-01-01

102

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

PubMed

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

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

2010-06-01

103

Thermodynamic properties for polycyclic systems by non-calorimetric methods  

SciTech Connect

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

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

1993-03-01

104

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

105

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

PubMed

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

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

2014-06-01

106

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

Microsoft Academic Search

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

Caroline Kilbourne Stahle

1992-01-01

107

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

Microsoft Academic Search

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

I. Nerád; E. Mikšíková

2010-01-01

108

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

Microsoft Academic Search

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

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

2005-01-01

109

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

Microsoft Academic Search

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

Erik Schmolz; Olaf Schulz

1995-01-01

110

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

Microsoft Academic Search

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

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

1980-01-01

111

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

Microsoft Academic Search

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

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

1980-01-01

112

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

Microsoft Academic Search

Plutonium pure metal products (PMP) are high purity plutonium metal items produced by electrorefining. The plutonium metal is produced as an approximately 3-kg ring. Accountability measurements for the electro-refining runs are typically balance\\/weight factor (incoming impure metal), chemistry (pure metal rings), and calorimetric assay or neutron counting of the crucibles and other wastes. The PMP items are qualified for their

Teresa L Cremers; Thomas E Sampson

2010-01-01

113

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

Microsoft Academic Search

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

J. Dziejowski; I. Bia?obrzewski

2011-01-01

114

Calorimetric and emf studies on liquid Li-Sn alloys  

Microsoft Academic Search

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

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

1986-01-01

115

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

116

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

NASA Astrophysics Data System (ADS)

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

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

1980-12-01

117

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

SciTech Connect

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

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

2007-09-10

118

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

NASA Astrophysics Data System (ADS)

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

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

2007-11-01

119

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

SciTech Connect

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

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

2013-07-01

120

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

SciTech Connect

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

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

1991-05-01

121

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

PubMed

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

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

2014-07-01

122

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

Microsoft Academic Search

Calorimetric and fluorescence techniques were used to characterize the binding of aminoglycosides-neomycin, paromomycin, and ribostamycin, with 5?-dA12-x-dT12-x-dT12-3? intramolecular DNA triplex (x = hexaethylene glycol) and poly(dA)·2poly(dT) triplex. Our results demonstrate the following features: (1) UV thermal analysis reveals that the Tm for triplex decreases with increasing pH value in the presence of neomycin, while the Tm for the duplex remains unchanged. (2)

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

2010-01-01

123

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

Microsoft Academic Search

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

S. Mehta; B. L. Deopura

1993-01-01

124

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

PubMed

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

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

2014-01-01

125

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

126

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

PubMed Central

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

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

2014-01-01

127

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

PubMed

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

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

1974-09-01

128

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

PubMed Central

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

Gentili, Rodolfo; Gentili, Elio; Sgorbati, Sergio

2009-01-01

129

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

National Technical Information Service (NTIS)

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

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

1969-01-01

130

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

Microsoft Academic Search

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

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

2010-01-01

131

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

Microsoft Academic Search

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

Reinhard Schubring

2004-01-01

132

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

SciTech Connect

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

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

2005-09-15

133

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

SciTech Connect

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

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

1988-10-10

134

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

135

A calorimetric study on interactions of colchicine with human serum albumin  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

136

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

NASA Astrophysics Data System (ADS)

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

Jaworske, Donald A.

1994-12-01

137

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

NASA Astrophysics Data System (ADS)

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

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

2010-11-01

138

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

SciTech Connect

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

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

1995-05-01

139

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

140

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

141

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

NASA Astrophysics Data System (ADS)

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

Tapan, Ilhan; Kocak, Fatma

2012-12-01

142

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

NASA Technical Reports Server (NTRS)

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

Jaworske, Donald A.

1994-01-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2005-06-01

144

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

SciTech Connect

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

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

1993-09-01

145

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

NASA Astrophysics Data System (ADS)

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

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

2008-05-01

146

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

147

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

PubMed

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

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

2010-01-21

148

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

NASA Astrophysics Data System (ADS)

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

Keenan, F. P.

1988-01-01

149

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

NASA Astrophysics Data System (ADS)

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

Dasgupta, Arati

1995-12-01

150

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

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

151

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

PubMed Central

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

Lewis, R N; McElhaney, R N

2000-01-01

152

Thermodynamics and selectivity of complexation of lithium and sodium thiocyanates with phosphorus-containing podands and compounds modeling the terminal groups of these podands  

Microsoft Academic Search

A series of model compounds and heptadentate neutral phosphorus-containing podands that differ in the conformational rigidity of the terminal groups and in the coordination properties of the phosphoryl groups were synthesized. The thermodynamic parameters of complexation and the cationic selectivity of organophosphorus compounds and podands with respect to LiNCS and NaNCS were studied by calorimetric titration in acetonitrile at 298

V. P. Solov'ev; V. E. Baulin; N. N. Strakhova; L. V. Govorkova

1994-01-01

153

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

NASA Technical Reports Server (NTRS)

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

Perez, Raul M.; Conroy, Bruce L.

1991-01-01

154

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

155

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

156

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

157

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

PubMed Central

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

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

2013-01-01

158

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

PubMed

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

Ketola-Pirie, C A; Atkinson, B G

1990-08-01

159

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

PubMed

In the past, process incidents attributed to organic peroxides (OPs) that involved near misses, over-pressures, runaway reactions, and thermal explosions occurred because of poor training, human error, incorrect kinetic assumptions, insufficient change management, and inadequate chemical knowledge in the manufacturing process. Calorimetric applications were employed broadly to test organic peroxides on a small-scale because of their thermal hazards, such as exothermic behavior and self-accelerating decomposition in the laboratory. In essence, methyl ethyl ketone peroxide (MEKPO) is highly reactive and exothermically unstable. In recent years, it has undergone many thermal explosions and runaway reaction incidents in the manufacturing process. Differential scanning calorimetry (DSC), vent sizing package 2 (VSP2), and thermal activity monitor (TAM) were employed to analyze thermokinetic parameters and safety index. The intent of the analyses was to facilitate the use of various auto-alarm equipments to detect over-pressure, over-temperature, and hazardous materials leaks for a wide spectrum of operations. Results indicated that MEKPO decomposition is detected at low temperatures (30-40 degrees C), and the rate of decomposition was shown to exponentially increase with temperature and pressure. Determining time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), maximum temperature (T(max)), exothermic onset temperature (T(0)), and heat of decomposition (DeltaH(d)) was essential for identifying early-stage runaway reactions effectively for industries. PMID:19619941

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

2009-11-15

160

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

PubMed

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

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

2012-05-30

161

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

NASA Astrophysics Data System (ADS)

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

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

1991-05-01

162

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

PubMed

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

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

2010-12-01

163

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

164

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

165

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

166

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

NASA Astrophysics Data System (ADS)

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

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

167

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

PubMed Central

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

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

2008-01-01

168

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

PubMed

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

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

2008-11-13

169

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

PubMed

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

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

2008-11-25

170

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

171

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

PubMed

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

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

2002-11-01

172

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

PubMed

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

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

2009-02-12

173

Compound Interest  

NSDL National Science Digital Library

Albert Einstein called compound interest the 8th wonder of the world. Find out why compound interest and the time value of money are so important. What is Interest Click on the following link to read about the different types of interest. Loans and Interest So why learn about compound interest? Using time and interest to your advantage, you can make more money than you have ever dreamed of. See how the time value of ...

Riches, Ms.

2007-10-16

174

Carbocyclic compounds  

US Patent & Trademark Office Database

Novel carbocyclic compounds are described. The compounds generally comprise an acidic group, a basic group, a substituted amino or N-acyl and a group having an optionally hydroxylated alkane moiety. Pharmaceutical compositions comprising the inhibitors of the invention are also described. Methods of inhibiting neuraminidase in samples suspected of containing neuraminidase are also described. Antigenic materials, polymers, antibodies, conjugates of the compounds of the invention with labels, and assay methods for detecting neuraminidase activity are also described.

1998-06-09

175

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

176

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

SciTech Connect

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

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

1993-12-01

177

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

NASA Astrophysics Data System (ADS)

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

Hovis, G. L.

2013-12-01

178

Thermochemical and thermophysical properties of organic nitrogen compounds found in fossil materials: Status report  

SciTech Connect

Thermochemical and thermophysical data on 24 organic nitrogen-containing compounds found in (or formed during the processing of) alternate fossil fuels are reported here. The data are combined to give ideal gas phase thermodynamic properties for 18 of the compounds. Statistical thermodynamic calculations for six of the compounds are given, and a comparison of statistically calculated values (including those previously published) and the calorimetric values obtained here is made. The results are used to determine the thermodynamic equilibrium conditions necessary for the removal of the nitrogen atom from the molecules. The report concludes with a discussion of future research in the area. This report is the first comprehensive compilation of thermochemical and thermophysical property data on organic nitrogen compounds present in the alternate fossil fuels. Removal of these compounds during processing is necessary for the production of stable, environmentally acceptable products. 71 refs., 11 figs., 13 tabs.

Steele, W.V.; Chirico, R.D.; Collier, W.B.; Hossenlopp, I.A.; Nguyen, A.; Strube, M.M.

1986-11-01

179

Polybenzimidazole compounds  

DOEpatents

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

Klaehn, John R. (Idaho Falls, ID); Peterson, Eric S. (Idaho Falls, ID); Orme, Christopher J. (Shelley, ID); Jones, Michael G. (Chubbuck, ID); Wertsching, Alan K. (Idaho Falls, ID); Luther, Thomas A. (Idaho Falls, ID); Trowbridge, Tammy L. (Idaho Falls, ID)

2011-11-22

180

Organosulfur Compounds  

NSDL National Science Digital Library

Quiz questions from the organic chemistry question bank provide students with an excellent opportunity to review key concepts. This set of questions focuses on organosulfur compounds, with a special emphasis on thiols and sulfides.

Reich, Ieva

2007-10-30

181

Polybenzimidazole compounds  

DOEpatents

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

Klaehn, John R. (Idaho Falls, ID); Peterson, Eric S. (Idaho Falls, ID); Wertsching, Alan K. (Idaho Falls, ID); Orme, Christopher J. (Shelley, ID); Luther, Thomas A. (Idaho Falls, ID); Jones, Michael G. (Pocatello, ID)

2010-08-10

182

Therapeutic compounds  

US Patent & Trademark Office Database

The present invention relates to pyrazolopyridines and imidazopyridines which are inhibitors of the kinase PDK1 and are thus useful for the treatment of myeloproliferative disorders or cancer. The compounds are also useful as inhibitors of other kinases such as FGFR3, NTRK3, RP-S6K and WEE1. Furthermore, the present compounds also selectively inhibit microtubule affinity regulating kinase (MARK) and are therefore useful for the treatment or prevention of Alzheimer's disease.

2013-06-04

183

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

NASA Astrophysics Data System (ADS)

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

Stahle, Caroline Kilbourne

184

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

PubMed

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

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

2010-05-01

185

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

186

The heat capacity, thermodynamic functions, and 4 f -electron states of rare-earth compounds: Rare-earth oxides of the A type  

Microsoft Academic Search

The paper deals with possible ways of approximating the contributions of the crystal lattice and 4f-electrons to the total heat capacity of rare-earth (RE) compounds. In estimating the heat capacity of the lattice, use is\\u000a made of the Debye model with due regard for the temperature dependence of the Debye temperature. The calorimetrically identified\\u000a values of the Schottky heat capacity

N. N. Morozov; E. N. Morozov

2000-01-01

187

Compound radiator  

NASA Astrophysics Data System (ADS)

Standard radiator design with a plate facing cold space on one side and the warm spacecraft at the other side suffers from considerable parasitic heat load to the radiator even when the back of the radiator is covered with the best Multi Layer Insulation (MLI) available. In addition, performance of the plate radiator depends crucially on its insulation which might well deteriorate over a long duration mission. In an attempt to address these manifest and potential problems the concept of a compound radiator was worked out. First tests confirm model calculations; the compound radiator marks a very significant improvement over a standard plate radiator.

Thomsen, Knud

1991-12-01

188

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2001-01-01

189

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

NASA Astrophysics Data System (ADS)

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

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

2003-06-01

190

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

191

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

192

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

PubMed

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

Roth, Jonathan V; Sea, Stephanie

2014-06-01

193

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

SciTech Connect

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

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

1986-01-01

194

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

PubMed

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

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

2006-07-01

195

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2003-01-01

196

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2006-01-01

197

Calorimetric study of glass transition in molecular liquids consisting of globular associates: dicyclorohexylmethanol and tricyclohexylmethanol.  

PubMed

Heat capacities of liquids and liquid-quenched glasses (LQGs) of dicyclorohexylmethanol (DCHM) and tricyclohexylmethanol (TCHM) were measured by adiabatic calorimetry. Upon cooling the liquid compounds, they undergo glass transitions around 250 and 265 K, respectively. Temperature dependence of the FT-IR spectrum of TCHM liquid showed the gradual formation of dimers in the supercooled state with decreasing temperature. The magnitude of heat capacity jump at glass transition is discussed through a comparison with other low-molecular mass LQG. Combining the present results with previous heat capacity results on crystalline TCHM, residual entropies of LQG and standard thermodynamic quantities are established for both compounds. PMID:22414072

Yamamura, Yasuhisa; Suzuki, Yu-ta; Sumita, Masato; Saito, Kazuya

2012-04-01

198

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2002-01-01

199

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2010-01-01

200

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2011-01-01

201

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2007-01-01

202

Intermetallic Compounds  

NASA Astrophysics Data System (ADS)

We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- ?V-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 ?.

Takagiwa, Y.; Matsuura, Y.; Kimura, K.

2014-06-01

203

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

SciTech Connect

On September 1, 1989 work was initiated on a project to extend the available vapor-liquid equilibrium (VLE) model for coal fluids to allow satisfactory predictions of excess enthalpies of coal liquids at high pressures. The current project involves measurement of some model compound VLE data and chromatographic characterization of coal liquids for distribution of heteroatoms. After one year, a thermodynamic model for VLE and excess enthalpies of defined mixtures of aromatic compounds has been developed. 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. Some progress has been made on binary VLE measurements and size exclusion chromatography of coal liquids. 11 refs., 5 tabs.

Kabadi, V.N.

1990-10-01

204

Magnesium compounds  

USGS Publications Warehouse

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

Kramer, D. A.

2012-01-01

205

Bismaleimide compounds  

DOEpatents

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

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

1986-01-14

206

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

NASA Astrophysics Data System (ADS)

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

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

1998-12-01

207

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

Microsoft Academic Search

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

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

2008-01-01

208

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

Microsoft Academic Search

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

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

1997-01-01

209

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

210

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

211

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

212

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

PubMed Central

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

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

2005-01-01

213

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

PubMed

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

Paul, Puja; Suresh Kumar, Gopinatha

2014-07-16

214

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

NASA Astrophysics Data System (ADS)

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

Mazeina, Lena; Navrotsky, Alexandra; Greenblatt, Martha

2008-02-01

215

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

NASA Astrophysics Data System (ADS)

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

Lanba, Asheesh; Hamilton, Reginald F.

2014-06-01

216

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

NASA Astrophysics Data System (ADS)

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

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

2009-01-01

217

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

218

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

219

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

220

Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin.  

PubMed

We observed biologically mediated emission of Po from culture solution inoculated sea sediment extract and incubated under natural light/dark cycle condition or dark condition the emitted Po compound would be lipophilic because of effective collection in organic solvent. Sterilization of the culture medium with antibiotics or CuSO4 completely suppressed growth of microorganisms and resulted in no emission of Po, indicating biological activity of microorganisms is responsible for formation and emission of volatile Po compound. Po emission also occurred when seawater was used as a culture medium. Our finding indicates a possibility of biotic source for atmospheric Po in the environment, which has been believed to be originated from abiotic sources. We compared emission behavior of Po and S in the culture experiments, the elements belong to XVI group in the Periodical Table, and consider that their emission mechanisms involved would be different though the emission of both elements is supported by biological activity of microorganisms. One of the chemical forms of S emitted was confirmed to be dimethyl sulfide (DMS) but that of Po is not known. Methylation experiments of Po with methylcobalamin demonstrated a formation and emission of volatile Po compound. The methylation of Po with methylcobalamin might be related to the observed Po emission in the culture experiments. PMID:11478248

Momoshima, N; Song, L X; Osaki, S; Maeda, Y

2001-07-15

221

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

PubMed

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

Maskow, T; Babel, W

2001-03-01

222

Modulated release of triterpenic compounds from a O\\/W\\/O multiple emulsion formulated with dimethicones: infrared spectrophotometric and differential calorimetric approaches  

Microsoft Academic Search

From the use of silicones within O\\/W\\/O multiple emulsions, we can expect, two principal advantages: (1) the silicones with the lowest molecular weight decrease the oily touch; (2) due to the large range of viscosity, this excipient should influence the skin distribution of actives after topical application. The purpose of our work is to highlight these advantages. Multiple emulsions were

C Laugel; P Rafidison; G Potard; L Aguadisch; A Baillet

2000-01-01

223

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

SciTech Connect

On September 1, 1989 work was initiated on a project to extend the available vapor-liquid equilibrium (VLE) model for coal fluids to allow satisfactory predictions of excess enthalpies of coal liquids at high pressures. The available vapor liquid equilibrium model was developed with support from previous grant from DOE-PETC (Grant no. DE-FG22-89PC90541). The current project also involves measurement of some model compound VLE data and chromatographic characterization of coal liquids for distribution of heteroatoms. A computational thermodynamic model for VLE, excess enthalpies and heat capacities of coal derived liquids has been developed. 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 computations are carried out using the method of continuous thermodynamics. Mode is used to derive interesting conclusions on the effect of oxygen, nitrogen, and sulfur heteroatoms on the thermodynamic properties of coal liquids. When compared with limited experimental data available for coal liquids the model shows good agreement. Some progress has been made on binary VLE measurements and size exclusion chromatography of coal liquids.

Kabadi, V.N.

1991-10-01

224

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

SciTech Connect

On September 1, 1989 work was initiated on a project to extend the available vapor-liquid equilibrium (VLE) model for coal fluids to allow satisfactory predictions of excess enthalpies of coal liquids at high pressures. The available vapor liquid equilibrium model was developed with support from previous grant from DOE-PETC (Grant no. DE-FG22-89PC90541). The current project also involves measurement of some model compound VLE data and chromatographic characterization of coal liquids for distribution of heteroatoms. A computational thermodynamic model for VLE, excess enthalpies and heat capacities of coal derived liquids has been developed. 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 computations are carried out using the method of continuous thermodynamics. Mode is used to derive interesting conclusions on the effect of oxygen, nitrogen, and sulfur heteroatoms on the thermodynamic properties of coal liquids. When compared with limited experimental data available for coal liquids the model shows good agreement. Some progress has been made on binary VLE measurements and size exclusion chromatography of coal liquids.

Kabadi, V.N.

1991-10-01

225

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

226

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

NASA Astrophysics Data System (ADS)

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

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

1988-10-01

227

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

PubMed

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

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

2008-10-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

229

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

230

Compounding in Ukraine.  

PubMed

Pharmaceutical compounding in modern Ukraine has a rich history and goes back to ancient times. Today in the Ukraine, there is a revival of compounding practice, the opening of private compounding pharmacies, updating of legislative framework and requirements of the State Pharmacopeia of Ukraine for compounding preparations, and the introduction of Good Pharmaceutical Practice. PMID:23696172

Zdoryk, Oleksandr A; Georgiyants, Victoriya A; Gryzodub, Oleksandr I; Schnatz, Rick

2013-01-01

231

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

232

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

233

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

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

234

Thermoelectric materials and chalcogenide compounds  

US Patent & Trademark Office Database

A thermoelectric material is disclosed. The thermoelectric material is represented by the following formula; (A.sub.1-aA'.sub.a).sub.4-x(B.sub.1-bB'.sub.b).sub.3-y. A is a Group XIII element and A' may be a Group XIII element, a Group XIV element, a rare earth element, a transition metal, or combinations thereof. A and A' are different from each other. B may be S, Se, Te and B' may be a Groups XIV, XV, XVI or combinations thereof. B and B' are different from each other. a is equal to or larger than 0 and less than 1. b is equal to or larger than 0 and less than 1. x is between -1 and 1 and wherein y is between -1 and 1.

2012-10-30

235

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

236

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

237

Micromechanical calorimetric sensor  

DOEpatents

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

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

2000-01-01

238

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

Microsoft Academic Search

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

Hagen Graebner; Ulrike Georgi; Regina Hüttl; Gert Wolf

1998-01-01

239

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

PubMed

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

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

2007-05-01

240

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

PubMed Central

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

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

2007-01-01

241

Decal Removal Compound.  

National Technical Information Service (NTIS)

The patent application describes a decal removal compound which loosens the adhesive which bonds the decal to an aircraft's painted surface without adversely affecting the underlying protective paint system. The compound includes three active solvents, vi...

J. H. Vinson

1975-01-01

242

Compositions comprising modafinil compounds  

US Patent & Trademark Office Database

Particle-forming compositions of modafinil compounds, and aqueous compositions of particles, wherein the particles comprise a modafinil compound, are disclosed, along with methods of their preparation, and their use in the treatment of diseases.

2010-07-06

243

Dinitroso and polynitroso compounds  

PubMed Central

The growing interest in the chemistry of C-nitroso compounds (RN=O; R = alkyl or aryl group) is due in part to the recognition of their participation in various metabolic processes of nitrogen-containing compounds. C-Nitroso compounds have a rich organic chemistry in their own right, displaying interesting intra- and intermolecular dimerization processes and addition reactions with unsaturated compounds. In addition, they have a fascinating coordination chemistry. While most of the attention has been directed towards C-nitroso compounds containing a single –NO moiety, there is an emerging area of research dealing with dinitroso and polynitroso compounds. In this critical review, we present and discuss the synthetic routes and properties of these relatively unexplored dinitroso and polynitroso compounds, and suggest areas of further development involving these compounds. (126 references.)

Gowenlock, Brian G.; Richter-Addo, George B.

2005-01-01

244

Compounds affecting cholesterol absorption  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

245

Photochemistry of uranium compounds  

SciTech Connect

This paper reviews the unclassified progress on the photochemistry of the following uranium compounds: UF/sub 6/, othe uranium halides, classical coordination complexes, uranium alkoxides, organometallic compounds, and uranium borohydride. Uranyl compounds are mentioned briefly. Recommendations for future studies are given. 61 references. (DLC)

Paine, R.T.; Kite, M.S.

1980-01-01

246

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

247

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

PubMed

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

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

2014-01-31

248

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

249

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

NASA Astrophysics Data System (ADS)

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

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

1989-10-01

250

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

251

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

PubMed

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

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

2013-12-01

252

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

NASA Astrophysics Data System (ADS)

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

Safaee-Rad, Reza; Aleksic, Milivoje

2011-02-01

253

[Ubiquitous perfluorinated compounds].  

PubMed

Perfluorinated compounds are derivatives of hydrocarbons, in which all or most of hydrogen atoms are substitiuted by fluorine atoms. These compounds are commonly used in many branches of industry. Perfluorinated compounds are in the limelight because of numerous reports concerning their toxicity and negative effects on human health as well as contradictory information about their cancerogenic effect. The above compounds are used in production of many commonly used products including such brand names as Gore-Tex, Teflon, Stainmaster. The most common ways of penetrating these compounds into a human organism are: via food, inhalation and skin contact. Perfluorooctanesulfonate (PFOS) has been added to the list of persistent organic pollutants (POPs). PMID:21980858

Kucharska, Agnieszka; Góralczyk, Katarzyna; Czaja, Katarzyna; Struci?ski, Pawe?; Hernik, Agnieszka; Korcz, Wojciech; Snopczy?iski, Tomasz; Ludwicki, Jan K

2011-01-01

254

Preparation of uranium compounds  

DOEpatents

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

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

2013-02-19

255

Thermodynamic properties for polycyclic systems by non-calorimetric methods. Progress report, August 1, 1992--September 30, 1993  

SciTech Connect

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

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

1993-03-01

256

Types of Compound Leaves  

NSDL National Science Digital Library

This illustrated guide is designed to help students recognize and learn the different types of compound leaves. The single Web page can be easily printed for use at field sites. Along with a short description, an illustration that identifies a leaflet and petiole is included for four types of compound leaves.

257

Analyzing Cranberry Bioactive Compounds  

Microsoft Academic Search

There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit—the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a

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

2010-01-01

258

Phosphorus-Nitrogen Compounds.  

National Technical Information Service (NTIS)

The chemistry of P-N compounds is characterized by the existence of polymeric compounds. Many derivatives of the six membered ring system (NPCl(sub2)) and of the eight membered system (NPCl(sub 2))(sub 4) are known Therefore, the reaction of PCl(sub 5) wi...

M. Becke-Goehring

1969-01-01

259

Magnetic and thermodynamic properties of Nd T2Ge 2 ( T=Pd, Ag) compounds  

NASA Astrophysics Data System (ADS)

Physical properties of NdPd 2Ge 2 and NdAg 2Ge 2, crystallizing with the tetragonal ThCr 2Si 2-type crystal structure, were investigated by means of magnetic, calorimetric, electrical transport as well as by neutron diffraction measurements. The specific heat studies and neutron diffraction measurements were performed down to 0.30 K and 0.47 K, respectively. Both compounds exhibit antiferromagnetic ordering below TN equal to 1.5 K for NdPd 2Ge 2 and 1.8 K for NdAg 2Ge 2. Neutron diffraction data for the latter germanide indicate antiferromagnetic collinear structure described by the propagation vector k=(0.5, 0, 0.5). The Nd magnetic moments equal to 2.24(5) ? B at 0.47 K are aligned along the a-axis and have the +- sequence within the crystal unit cell. For NdPd 2Ge 2 only very small Bragg peaks of magnetic origin were observed in the neutron diffraction patterns measured below TN, thus hampering determination of the magnetic structure. Both compounds exhibit metallic-like electrical conduction. From the specific heat data the crystal electric field (CEF) levels schemes were determined. Difference between the overall CEF splitting in the two compounds is correlated with their structural parameters.

Gondek, ?.; Penc, B.; Kaczorowski, D.; Baran, S.; Hoser, A.; Gerischer, S.; Szytu?a, A.

2010-04-01

260

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

Microsoft Academic Search

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

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

2005-01-01

261

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

Microsoft Academic Search

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

Sylvie Pimbert; Guy Levesque

1997-01-01

262

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

PubMed

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

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

2000-01-01

263

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

PubMed

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

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

2014-07-01

264

Organic Compounds Database  

NSDL National Science Digital Library

The Colby College Department of Chemistry offers the Organic Compounds Database, which was compiled by Harold Bell of the Virginia Polytechnic Institute. Visitors can search by the compounds melting point, boiling point, index of refraction, molecular weight, formula, absorption wavelength, mass spectral peak, chemical type, and by partial name. Once entered, results are returned with basically the same type of information that can be searched, plus any other critical information. References are provided for the close to 2500 organic compounds included in the database; yet, because the site was last modified in 1995, varying the data may be required to fully authenticate its accuracy.

Bell, Harold M.

2000-01-01

265

Edheads: The Compound Machine  

NSDL National Science Digital Library

This resource is a collection of interactive animations designed to help kids learn how forces and simple machines can work together to create the compound machine. Child-centered animated activities enhance understanding of how compound machines function and how they are differentiated from simple machines. Additionally the site includes a glossary of important terms, lesson plans, a teacher's guide and information about professionals who work with compound machines. This page is part of a larger collection of animated education resources for the elementary level.

2007-09-18

266

Active compound combinations  

US Patent & Trademark Office Database

The invention relates to active compound combinations, in particular within a composition, which comprises (A) an amidine compound of formula (I) and a further fungicidally (B-1), insecticidally (B-2) active or plant growth regulating compound (B-3). Moreover, the invention relates to a method for curatively or preventively controlling the phytopathogenic fungi of plants or reducing the mycotoxin contamination of plant or plant parts, to the use of a combination according to the invention for the treatment of seed, to a method for protecting a seed and not at least to the treated seed. ##STR00001##

2013-09-10

267

Heart testing compound  

DOEpatents

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

Knapp, Jr., Furn F. (Oak Ridge, TN); Goodman, Mark M. (Knoxville, TN)

1985-01-01

268

Research on Intermetallic Compounds.  

National Technical Information Service (NTIS)

Laboratory effort was directed toward producing pure, nonporous samples of selected intermetallic compounds in the molybdenum-aluminum, molybdenum-germanium, molybdenum-selenium, and molybdenum-tellurium systems. Although samples of the desired phases wer...

M. Semchyshen J. Dahl C. Hallada J. Mair

1967-01-01

269

Ultraviolet radiation screening compounds  

Microsoft Academic Search

Amongst the diversity of methods used by organisms to reduce damage caused by ultraviolet (UV) radiation, the synthesis of UV-screening compounds is almost ubiquitous. UV-screening compounds provide a passive method for the reduction of UV-induced damage and they are widely distributed across the microbial, plant and animal kingdoms. They share some common chemical features. It is likely that on early

CHARLES S. COCKELL; JOHN KNOWLAND

1988-01-01

270

Photoswitchable coordination compounds  

Microsoft Academic Search

Photoswitchable compounds represent an attractive class of materials in coordination chemistry. Recent progress dealing with transition metal compounds involving photo-induced changes of the magnetic and\\/or optical properties to long-lived metastable states are covered in the present review article. The basic photophysical phenomena together with representative examples such as nitroprusside derivatives, relevant spin crossover complexes, stilbenoid complexes and finally Prussian blue

Philipp Gütlich; Yann Garcia; Theo Woike

2001-01-01

271

Understanding medication compounding issues.  

PubMed

The potential for contamination of compounded products and the resulting infections are a serious threat to patient safety. Immediate use products are used frequently in the perioperative department, and perioperative nurses should be familiar with the guidelines and practices that aim to reduce the contamination that can occur during the sterile compounding process. Four common themes lead to successful compounding: quality (eg, product identification, purity, stability, compatibility, risk level assessment), the environment (eg, using a segregated compounding area with specialized airflow capabilities, reducing particulate matter, practicing proper hand hygiene, performing gloved fingertip sampling, properly cleaning equipment and work areas), personnel activities (eg, familiarity with types of containers used and how often they can be accessed, following expiration dates and the number of times containers can be accessed), and the control process (eg, process monitoring, quality improvement). If a third-party vendor is contracted to handle compounding for a facility, perioperative personnel should be aware of the responsibilities for the facility and the vendor to ensure a quality compounding program. PMID:24674793

Hicks, Rodney W

2014-04-01

272

Calorimetric and dielectric studies of the (NH4)2MoO2F4 oxyfluoride  

NASA Astrophysics Data System (ADS)

The temperature dependences of the heat capacity, dielectric properties, and response to an external pressure and an electric field for the (NH4)2MoO2F4 oxyfluoride (space group Cmcm, Z = 4) have been studied. A comparative analysis of the data on the entropy of phase transitions, p-T phase diagrams, permittivity, and anomalous heat capacity in combination with the results of previous studies of the related compounds (NH4)2WO2F4 and (ND4)2WO2F4 has made it possible to establish that both [ MO2F4]2- anions and ammonium groups play a substantial role in the mechanism and nature of the structural transformations.

Fokina, V. D.; Bogdanov, E. V.; Pogorel'Tsev, E. I.; Bondarev, V. S.; Flerov, I. N.; Laptash, N. M.

2010-01-01

273

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

NASA Astrophysics Data System (ADS)

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

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

2005-11-01

274

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

PubMed

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

Drozd, M; Dudzic, D; Pietraszko, A

2013-03-15

275

Biodegradation of nitroaromatic compounds.  

PubMed

Nitroaromatic compounds are released into the biosphere almost exclusively from anthropogenic sources. Some compounds are produced by incomplete combustion of fossil fuels; others are used as synthetic intermediates, dyes, pesticides, and explosives. Recent research revealed a number of microbial systems capable of transforming or biodegrading nitroaromatic compounds. Anaerobic bacteria can reduce the nitro group via nitroso and hydroxylamino intermediates to the corresponding amines. Isolates of Desulfovibrio spp. can use nitroaromatic compounds as their source of nitrogen. They can also reduce 2,4,6-trinitrotoluene to 2,4,6-triaminotoluene. Several strains of Clostridium can catalyze a similar reduction and also seem to be able to degrade the molecule to small aliphatic acids. Anaerobic systems have been demonstrated to destroy munitions and pesticides in soil. Fungi can extensively degrade or mineralize a variety of nitroaromatic compounds. For example, Phanerochaete chrysosporium mineralizes 2,4-dinitrotoluene and 2,4,6-trinitrotoluene and shows promise as the basis for bioremediation strategies. The anaerobic bacteria and the fungi mentioned above mostly transform nitroaromatic compounds via fortuitous reactions. In contrast, a number of nitroaromatic compounds can serve as growth substrates for aerobic bacteria. Removal or productive metabolism of nitro groups can be accomplished by four different strategies. (a) Some bacteria can reduce the aromatic ring of dinitro and trinitro compounds by the addition of a hydride ion to form a hydride-Meisenheimer complex, which subsequently rearomatizes with the elimination of nitrite. (b) Monooxygenase enzymes can add a single oxygen atom and eliminate the nitro group from nitrophenols. (c) Dioxygenase enzymes can insert two hydroxyl groups into the aromatic ring and precipitate the spontaneous elimination of the nitro group from a variety of nitroaromatic compounds. (d) Reduction of the nitro group to the corresponding hydroxylamine is the initial reaction in the productive metabolism of nitrobenzene, 4-nitrotoluene, and 4-nitrobenzoate. The hydroxylamines undergo enzyme-catalyzed rearrangements to hydroxylated compounds that are substrates for ring-fission reactions. Potential applications of the above reactions include not only the biodegradation of environmental contaminants, but also biocatalysis and synthesis of valuable organic molecules. PMID:8561470

Spain, J C

1995-01-01

276

Organic compounds in meteorites  

NASA Technical Reports Server (NTRS)

The problem of whether organic compounds originated in meteorites as a primary condensate from a solar gas or whether they were introduced as a secondary product into the meteorite during its residence in a parent body is examined by initially attempting to reconstruct the physical conditions during condensation (temperature, pressure, time) from clues in the inorganic matrix of the meteorite. The condensation behavior of carbon under these conditions is then analyzed on the basis of thermodynamic calculations, and compounds synthesized in model experiments on the condensation of carbon are compared with those actually found in meteorites. Organic compounds in meteorites seem to have formed by catalytic reactions of carbon monoxide, hydrogen, and ammonia in the solar nebula at 360 to 400 K temperature and about 3 to 7.6 microtorr pressure. The onset of these reactions was triggered by the formation of suitable catalysts (magnetite, hydrated silicates) at these temperatures.

Anders, E.; Hayatsu, R.; Studier, M. H.

1973-01-01

277

Sulfur compounds in coal  

NASA Technical Reports Server (NTRS)

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

Attar, A.; Corcoran, W. H.

1977-01-01

278

Metalloid compounds as drugs.  

PubMed

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

Sekhon, B S

2013-07-01

279

Metalloid compounds as drugs  

PubMed Central

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

Sekhon, B. S.

2013-01-01

280

Microoptical compound lens  

DOEpatents

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

Sweatt, William C. (Albuquerque, NM); Gill, David D. (Albuquerque, NM)

2007-10-23

281

Compounding practices in Iran.  

PubMed

This article has been presented by pharmacists of the Razi Hospital Pharmacy, which is located within the Dermatology Center of Tehran University of Medical Sciences in Tehran, Iran, and by members of the staff at the Tehran University of Medical Sciences. Discussed within this article are the legalization and regulation of pharmaceutical compounding in Iran, the restrictions on pharmaceutical compounding, the general equipment used in Iran pharmacies, beyond-use dating/expiration dating, the required pharmacy education, as well as information related specifically to Razi Hospital Pharmacy. PMID:24881113

Goodarzi, Navid; Niknam, Somayeh; Akbarzadeh, Tahmineh; Gholami, Kheirollah

2014-01-01

282

Statin-like compounds  

US Patent & Trademark Office Database

The present invention relates to compounds with structures resembling natural statins isolated from Penicillium sp. (Formula I); where R.sub.1 represents OH, C.sub.6H.sub.5COO, R.sub.6COO and R.sub.6 represents C.sub.1 C.sub.5 alkyl; R.sub.2-4 represents H, C.sub.1 C.sub.5 alkyl C.sub.1 C.sub.5 acyl, R.sub.5 represents H, CH.sub.3; and X represents a compound of (Formula II) or (Formula III) ##STR00001##

2007-12-04

283

Cyclic carbonyl compounds  

US Patent & Trademark Office Database

Certain fluorenone and anthraquinone compounds, each of which is 2-substituted by a carboxyl group or a salt, ester or optionally substituted amide thereof and each of which is optionally substituted in the 5,6-,7- or 8- position, by a second carboxyl group, salt, ester or optionally substituted amide thereof, the substitutent in the 5,6-7- or 8- position of the fluorenone compounds, also being selected from cyano, halogen, nitro, alkyl, alkoxy and acyl, are useful for the relief or prophylaxis of allergic conditions.

1976-02-17

284

Aminopropyl thiophene compounds  

DOEpatents

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

Goodman, Mark M. (Knoxville, TN); Knapp, Jr., Furn F. (Oak Ridge, TN)

1990-01-01

285

Resultative Verb Compounds.  

ERIC Educational Resources Information Center

Demonstrates that structure and interpretation of Resultative Verb Compound (RVC) in the field of Chinese linguistics is neither indiosyncratic nor pragmatically determined as suggested in an earlier study. Rather, RCV formation and interpretation is determined by semantic features of verbs, and these features determine the well-formedness and…

Ross, Claudia

1990-01-01

286

Aminopropyl thiophene compounds  

SciTech Connect

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

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

1990-04-03

287

Noun Compounding in Thai.  

ERIC Educational Resources Information Center

The present study, a slightly revised version of the author's 1968 Ph.D. thesis presented to the University of Chicago, investigates compound formation in Thai. Chapter 1 summarizes the transformational generative theory on which the study is based, discusses the concept that Thai is a "simple" language in comparison with English, and briefly…

Fasold, Ralph William August

288

Urinary Compounds in Autism  

ERIC Educational Resources Information Center

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

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

2004-01-01

289

Compound floating pivot micromechanisms  

SciTech Connect

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

Garcia, Ernest J. (Albuquerque, NM)

2001-04-24

290

Lithiation of Trimethylsilyl Compounds.  

National Technical Information Service (NTIS)

Lithiation of tetramethylsilane by n-butyllithium in the presence of N,N,N',N'-tetramethyl ethylenediamine (TMEDA) has been reported. The authors found that certain methylsilyl compounds can be metalated in the methyl group by t-butyllithium even when the...

G. A. Gornowicz R. West

1968-01-01

291

8-fluoropurine compounds  

DOEpatents

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

Barrio, Jorge R. (Agoura Hills, CA); Satyamurthy, Nagichettiar (Los Angeles, CA); Namavari, Mohammad (Los Angeles, CA); Phelps, Michael E. (Encino, CA)

2001-01-01

292

PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS  

EPA Science Inventory

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

293

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

SciTech Connect

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

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

1993-10-01

294

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

PubMed

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

Benesch, Matthew G K; McElhaney, Ronald N

2014-07-01

295

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

PubMed

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

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

2010-01-01

296

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

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

297

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

PubMed

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

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

2008-08-01

298

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

299

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

SciTech Connect

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

Kabadi, V.N. [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Chemical Engineering] [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Chemical Engineering; Chen, J.C. [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Mechanical Engineering] [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Mechanical Engineering

1996-10-01

300

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

Microsoft Academic Search

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

Hitoshi Yusa; Masaki Akaogi; Eiji Ito

1993-01-01

301

Structures and standard molar enthalpies of formation of a series of Ln(III)-Cu(II) heteronuclear compounds with pyrazine-2,3-dicarboxylic acid  

NASA Astrophysics Data System (ADS)

Fifteen lanthanide-copper heteronuclear compounds, formulated as [CuLn2(pzdc)4(H2O)6]·xH2O (1-6(x=2), 8(x=3), 9-10(x=4); [CuLn2(pzdc)4(H2O)4]·xH2O (7, 12-13, 15(x=4), 14(x=5), 11(x=8) (Ln(III)=La(1); Ce(2); Pr(3); Nd(4); Sm(5); Eu(6); Gd(7); Tb(8); Dy(9); Ho(10); Er(11); Tm(12); Yb(13); Lu(14); Y(15); H2pzdc (C6H4N2O4)=pyrazine-2,3-dicarboxylic acid) have been hydrothermally synthesized. All compounds were characterized by element analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analyses confirm that all compounds are isostructural and feature a 3D brick-like framework structure with {4.62}2{42.62.82}{63}2{65.8}2 topology. Using 1 mol cm-3 HCl(aq) as calorimetric solvent, with an isoperibol solution-reaction calorimeter, the standard molar enthalpies of formation of all compounds were determined by a designed thermochemical cycle. In addition, solid state luminescence properties of compounds 5, 6, 8 and 9 were studied in the solid state.

Yang, Qi; Xie, Gang; Wei, Qing; Chen, Sanping; Gao, Shengli

2014-07-01

302

Organic compounds in meteorites  

NASA Technical Reports Server (NTRS)

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

Lawless, J. G.

1980-01-01

303

Immunomodulating compounds in Basidiomycetes.  

PubMed

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

Mizuno, Masashi; Nishitani, Yosuke

2013-05-01

304

Diphenyl Ether Antimicrobial Compounds.  

National Technical Information Service (NTIS)

The present invention is directed to compounds having the formula: wherein A(sup 1), A(sup 3), A(sup 6), and A(sup 8) independently represent CH or N; A(sup 2) represents N or C--X(sup 1)(sub a)--R(sup 1); A(sup 4) represents N or C--X(sup 2)(sub b)--R(su...

F. Johnson P. J. Tonge T. Sullivan

2005-01-01

305

Immunomodulating compounds in Basidiomycetes  

PubMed Central

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

Mizuno, Masashi; Nishitani, Yosuke

2013-01-01

306

Antitumor compounds from tunicates.  

PubMed

Of the six marine-derived compounds that have reached clinical trials as antitumor agents three-didemnin B, Aplidine, and ecteinascidin 743-are derived from tunicates. Di-demnin B (DB), a cyclic depsipeptide from the compound tunicate Trididemnum solidum, was the first marine-derived compound to enter Phases I and II clinical trials. The Phase II studies, sponsored by the U. S. National Cancer Institute, indicated complete or partial remissions with non-Hodgkins lymphoma, but cardiotoxicity caused didemnin B to be dropped from further study. The closely related dehydrodidemnin B (DDB, Aplidine) was isolated in 1988 from a second colonial tunicate, Aplidium albicans, and spectroscopic studies assigned a structural formula in which a pyruvyl group in DDB replaced the lactyl group in DB and syntheses of DDB have been achieved. Aplidine is more active than DB and lacks DB's cardiotoxicity. It was introduced by PharmaMar into Phase I clinical trials in January 1999. The second family of tunicate-derived antitumor agents are the ecteinascidins (ETs), from the mangrove tunicate Ecteinascidia turbinata. The antitumor extracts of E. turbinata were first described in 1969, but the small amount of ETs in E. turbinata prevented their isolation for over a decade. The structures of ETs have been assigned mainly by spectroscopy. Phase II clinical trials with ET 743 are underway. Future supplies of ET's should be available from aquaculture or synthesis. PMID:10608919

Rinehart, K L

2000-01-01

307

Compound semiconductor SPAD arrays  

NASA Astrophysics Data System (ADS)

Single photon avalanche diodes (SPADs) are revolutionizing ultra-sensitive photodetection applications, providing single photon sensitivity, high quantum efficiency and low dark noise at or near room temperature. When aggregated into arrays, these devices have demonstrated the ability to operate as photon number resolving detectors with wide dynamic range, or as single-photon imaging detectors. SPAD array performance has reached a point where replacing vacuum tube based MCP and PMT photodetectors for most applications is inevitable. Compound semiconductor SPAD arrays offer the unique proposition to tailor performance to match application specific wavelength, speed and radiation hardness requirements. We present a theoretical framework describing performance limits to compound semiconductor SPAD arrays and our latest experimental results detailing the performance of GaAs SPAD arrays. These devices achieve nanosecond rise and fall times, excellent photon number resolving capability, and low dark count rates. Single photon number resolving is demonstrated with 4% single photon detection efficiency at room temperature with dark count rates below 7 Mcps/mm2. Compound semiconductor SPAD arrays have the opportunity to provide orders of magnitude improvement in dark count rate and radiation hardness over silicon SPAD arrays, as well as the ability to detect wavelengths where silicon is blind.

Harmon, Eric S.; Naydenkov, Mikhail; Hyland, James T.

2013-06-01

308

Toxic compounds in honey.  

PubMed

There is a wealth of information about the nutritional and medicinal properties of honey. However, honey may contain compounds that may lead to toxicity. A compound not naturally present in honey, named 5-hydroxymethylfurfural (HMF), may be formed during the heating or preservation processes of honey. HMF has gained much interest, as it is commonly detected in honey samples, especially samples that have been stored for a long time. HMF is a compound that may be mutagenic, carcinogenic and cytotoxic. It has also been reported that honey can be contaminated with heavy metals such as lead, arsenic, mercury and cadmium. Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. In addition, Melicope ternata and Coriaria arborea from New Zealand produce toxic honey that can be fatal. There are reports that honey is not safe to be consumed when it is collected from Datura plants (from Mexico and Hungary), belladonna flowers and Hyoscamus niger plants (from Hungary), Serjania lethalis (from Brazil), Gelsemium sempervirens (from the American Southwest), Kalmia latifolia, Tripetalia paniculata and Ledum palustre. Although the symptoms of poisoning due to honey consumption may differ depending on the source of toxins, most common symptoms generally include dizziness, nausea, vomiting, convulsions, headache, palpitations or even death. It has been suggested that honey should not be considered a completely safe food. Copyright © 2013 John Wiley & Sons, Ltd. PMID:24214851

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

2014-07-01

309

Offset Compound Gear Drive  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

310

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

NASA Astrophysics Data System (ADS)

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

Johari, G. P.; Khouri, J.

2013-03-01

311

Boronated porphyrin compounds  

DOEpatents

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

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

1992-09-22

312

Active compound combinations  

US Patent & Trademark Office Database

The invention relates to active compound combinations, in particular a fungicidal and/or insecticidal composition, comprising Isotianil (3,4-dichloro-N-(2-cyanophenyl)-5-isothiazolecarboxamide) and at least one further insecticide of the tetronic acid derivatives group and optionally one further insecticide of the neonicotinoids. Moreover, the invention relates to a method for curatively or preventively controlling the phytopathogenic fungi and/or microorganisms and/or pests of plants or crops, to the use of a combination according to the invention for the treatment of seed, to a method for protecting a seed and not at least to the treated seed.

2014-02-18

313

Terahertz plastic compound lenses.  

PubMed

We present terahertz (THz) lenses made of highly refracting polymeric compounds which provide a better focusing performance and an increased functionality in comparison to conventional THz lenses. Using mixtures consisting of polypropylene (PP) and alumina as well as PP and zinc sulfide allows a significant increase of the refractive index while simultaneously keeping a low extinction and dispersion. With these new material combinations, lenses with an increased focusing capability are realized. This is evaluated by focal plane measurements using a fiber coupled THz time-domain spectrometer. PMID:23842159

Wichmann, M; Mondol, A S; Kocic, N; Lippert, S; Probst, T; Schwerdtfeger, M; Schumann, S; Hochrein, T; Heidemeyer, P; Bastian, M; Bastian, G; Koch, M

2013-06-20

314

Boronated porphyrin compounds  

DOEpatents

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

Kahl, Stephen B. (Portola Valley, CA); Koo, Myoung-Seo (San Francisco, CA)

1992-01-01

315

Novel Vinblastine and Vincristine Compounds.  

National Technical Information Service (NTIS)

Novel 3', 4'-dehydro- and 4'-deoxo-vincristine and vinblastine compounds are obtained by coupling an indole unit of the catharanthine series and a dihydroindole unit of the vindoline series. Representative compounds of this series showed superior results ...

J. P. Kutney

1977-01-01

316

Special Risks of Pharmacy Compounding  

MedlinePLUS

... Consumer Updates RSS Feed The Special Risks of Pharmacy Compounding Search the Consumer Updates Section Get Consumer ... page: A Troubling Trend What You Can Do Pharmacy compounding is a practice in which a licensed ...

317

Color Classification of Coordination Compounds.  

ERIC Educational Resources Information Center

Proposes that colored compounds be classified by reference to a standard color-order system incorporating a color dictionary. Argues that the colors of new compounds could be incorporated into the characterization process and into computer storage systems. (TW)

Poncini, Laurence; Wimmer, Franz L.

1987-01-01

318

Heterocyclic compounds and uses thereof  

US Patent & Trademark Office Database

Compounds and pharmaceutical compositions that modulate kinase activity, including PI3 kinase activity, and compounds, pharmaceutical compositions, and methods of treatment of diseases and conditions associated with kinase activity, including PI3 kinase activity, are described herein.

2014-07-22

319

Potential Antimalarial Organic Sulfur Compounds.  

National Technical Information Service (NTIS)

In an attempt to develop useful antimalarial medicinal agents, a series of twenty two organic sulfur compounds were synthesized which were analogous in structure to 4,4'-diaminodiphenyl sulfone an effective antimalarial. Fifteen of these compounds were N-...

K. K. Andersen J. Bhattacharyya S. K. Mukhopadhyay

1969-01-01

320

Organoselenium Compounds for Cancer Chemoprevention.  

National Technical Information Service (NTIS)

A compound containing an alkylene selenocyanate or an alkylene isoselenocyanate moiety effective to prevent the occurrence or progression of cancer or a precancerous condition. The compound can be provided and administered in the form of a pharmaceutical ...

L. K. T. Lam N. Ahmed

2005-01-01

321

Formulation of Boronic Acid Compounds.  

National Technical Information Service (NTIS)

The invention relates to the formulation of pharmaceutical compounds. More particularly, the invention provides stable, pharmaceutically acceptable compositions prepared from boronic acid compounds and methods for preparing the compositions. The invention...

L. Plamondon L. Grenier J. Adams S. L. Gupta

2005-01-01

322

Elevational spatial compounding.  

PubMed

Spatial compounding has long been explored to reduce coherent speckle noise in medical ultrasound. By laterally translating a one-dimensional array, partially correlated measurements made at different look directions can be obtained and incoherently averaged. The lateral resolution, however, is limited by the sub-array length used for each independent measurement. To reduce speckle contrast without compromising lateral resolution, a new spatial compounding technique using two-dimensional, anisotropic arrays is proposed. This technique obtains partially correlated measurements by steering the image plane elevationally with small inclinations. Incoherent averaging is then performed by adding image magnitudes. Therefore, contrast resolution is improved only at the price of a slightly wider elevational beam. Note that although anisotropic arrays have limited steering capability in elevation, grating lobes are not considered influential since only small inclinations are needed between measurements. Simulations have been performed to show both the change in spatial resolution and the improvement in contrast resolution. Results indicated minimal increase in the correlation length both laterally and axially. It was also shown that detectability can be significantly enhanced by increasing the number of measurements or increasing the differential inclination between measurements. This technique is therefore effective for reducing speckle noise while maintaining in-plane spatial resolution. Furthermore, it demonstrates a new application of two-dimensional anisotropic arrays in spite of their limited elevational steering capability. PMID:7839557

Li, P C; O'Donnell, M

1994-07-01

323

Dioxin and Related Compounds  

NSDL National Science Digital Library

This substantial new site, provided by the Environmental Protection Agency's National Center for Environmental Assessment, addresses the mechanism of Dioxin contamination and describes NCEA's Dioxin Reassessment efforts. The site provides full descriptions and molecular graphics of "Dioxins and related compounds" (Furans, PCB's), as well as EPA Summaries on Dioxin exposure, Dioxin risk, and dose response. The Dioxin Exposure Initiative seeks to quantitatively link dioxin sources to general population exposures using "source measurements, environmental media and national food surveys, and fate and transport modeling." Further links to EPA Regulations and EPA Analytical Methods round out the site. Note that many of the documents at the site are available in Adobe Acrobat (.pdf) or WordPerfect format.

1994-01-01

324

Turbo compound engine  

SciTech Connect

A turbo compound engine having a first exhaust turbine coupled to an exhaust pipe of an internal combustion engine and a second exhaust turbine coupled to an exhaust port of the first exhaust turbine is described comprising: a first generator drivable by the first exhaust turbine; a second generator drivable by the second exhaust turbine; a motor operatively coupled to an output shaft of the internal combustion engine; speed detecting means for detecting the speed of rotation of the internal combustion engine; and control means for controlling the frequency of electric power, which is the sum of electric power outputs from the first and second generators and supplied to the motor, based on a signal from the speed detecting means, in order to control operation of the motor.

Kawamura, H.

1988-05-24

325

Common Compound Library  

NSDL National Science Digital Library

This database, part of a college-level chemistry course, provides information on hundreds of compounds, elements, and substances encountered in introductory chemistry courses and in everyday life. The informaion includes chemical synonyms, molecular weights, structures, equilibrium constants, thermodynamic properties, and common uses, with properties presented in a variety of common units. Structure information includes flat structural formulas, ball and stick models, electron density/electric potential maps, and Chime "live" structures that can be rotated and queried for bond lengths, bond angles, and torsion angles. The site also includes links to the course website, a glossary, a frequently-asked-questions feature, information on sources used in constructing the database, and many other resources.

Senese, Frederick A.

326

Thermodynamics of organic compounds  

NASA Astrophysics Data System (ADS)

This research program consisted of an integrated and interrelated effort of basic and applied research in chemical thermodynamics and thermochemistry. Knowledge of variation of physical and thermodynamic properties with molecular structure was used to select compounds for study that because of high ring strain or unusual steric effects may have good energy characteristics per unit volume or per unit mass and thus be useful in the synthesis of high energy fuels. These materials were synthesized, and their thermodynamic properties were evaluated. In cooperation with researcher at Wright-Patterson Air Force Base, ramjet fuels currently in use were subjected to careful thermodynamic evaluation by measurements of heat capacity, enthalpy of combustion and vapor pressure. During the last year of this effort, seven kerosene-type fuels produced by British Petroleum and seven jet fuels produced from shale oil were studied.

Gammon, B. E.; Smith, N. K.

1982-11-01

327

[Energies of organic compounds  

SciTech Connect

The enthalpy of reduction of lactones to the corresponding diols has been determined, allowing the enthaipies of formation of the lactones to be determined. Results of this study agree well with data obtained for enthalpies of hydrolysis of the lactones. We have begun the measurement of the enthalpies of reduction of norbornanones, and we have shown that it is possible to determine the difference in energy between the exo and endo forms of the product alcohols by measuring the equilibrium constant as a function of temperature. The study of the enthalpies of hydration of carbonyl compounds has continued, and the enthalpies of hydrolysis of the corresponding ketals is being determined. The study of the enthalpies of hydration of alkenes is nearly completed, and the rearrangement reactions which were uncovered are being investigated.

Wiberg, K.B.

1991-12-31

328

Energies of organic compounds  

SciTech Connect

The enthalpy of reduction of lactones to the corresponding diols has been determined, allowing the enthalpies of formation of the lactones to be determined. The results of this study agree well with the data we have obtained for the enthalpies of hydrolysis of the lactones. We have begun the measurement of the enthalpies of reduction of norbornanones, and we have shown that it is possible to determine the difference in energy between the exo and endo forms of the product alcohols by measuring the equilibrium constant as a function of temperature. The study of the enthalpies of hydration of carbonly compounds has continued, and the enthalpies of hydrolysis of the corresponding ketals is being determined. The study of the enthalpies of hydration of alkenes is nearly completed, and the rearrangement reactions which were uncovered are being investigated.

Not Available

1990-01-01

329

Preliminary Report on the Thermodynamic Properties of Selected Light-Element and Some Related Compounds.  

National Technical Information Service (NTIS)

This report presents improved values for the heats of formation and some other thermodynamic properties of a number of light-element substances -- resulting from recent NBS experimental studies (calorimetric, vaporization, and spectroscopic) and critical ...

C. W. Beckett T. B. Douglas

1967-01-01

330

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

331

Forschungszentrum jülich hosts icans-xvi  

Microsoft Academic Search

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

Harald Conrad

2003-01-01

332

Compounded oral ketamine.  

PubMed

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

McNulty, Jack P; Hahn, Kristian

2012-01-01

333

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

PubMed Central

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

Krivanek, Roland; Okoro, Linus; Winter, Roland

2008-01-01

334

Compound power plant  

SciTech Connect

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

Smith, R.R.

1991-02-05

335

TSTA compound cryopump  

SciTech Connect

The Tritium System Test Assembly (TSTA), at the Los Alamos Scientific Laboratory, is intended to demonstrate realistic fuel supply and cleanup scenarios for future fusion reactors. The vacuum pumps must be capable of handling large quantities of reactor exhaust gases consisting largely of mixtures of hydrogen and helium isotopes. Cryocondensing pumps will not pump helium at 4.2 K; while cryosorption pumps using molecular sieves or charcoal have good helium pumping speed, the adsorbent clogs with condensed hydrogen while pumping mixtures of both. A solution to this problem is a compound design whereby the first stage condenses the hydrogen species and the second, or sorption, stage pumps the helium. The TSTA pump designed at Lawrence Livermore National Laboratory uses argon gas to cryotrap the helium in the helium--hydrogen mixture. The argon is sprayed directly onto the 4.2 K surface at a rate proportional to the helium flow rate, permitting continuous pumping of the helium--hydrogen mixtures in a single-stage pump. However, the possibility of differential desorption as a first stage in the TSTA gas separation cycle required the inclusion of a first-state hydrogen isotope condenser. The design, performance, and operating characteristics are discussed.

Batzer, T.H.; Patrick, R.E.; Call, W.R.

1981-04-01

336

TSTA compound cryopump  

SciTech Connect

The Tritium System Test Assembly (TSTA), at the Los Alamos Scientific Laboratory, is intended to demonstrate realistic fuel supply and cleanup scenarios for future fusion reactors. The vacuum pumps must be capable of handling large quantities of reactor exhaust gases consisting largely of mixtures of hydrogen and helium isotopes. Cryocondensing pumps will not pump helium at 4.2 K; while cryosorption pumps using molecular sieves or charcoal have good helium pumping speed, the adsorbent clogs with condensed hydrogen while pumping mixtures of both. A solution to this problem is a compound design whereby the first stage condenses the hydrogen and the second, or sorption, stage pumps the helium. The TSTA pump designed at Lawrence Livermore National Laboratory uses argon gas to cryotrap the helium in the helium-hydrogen mixture. The argon is sprayed directly onto the 4.2 K surface at a rate proportional to the helium flow rate, permitting continuous pumping of the helium-hydrogen mixtures in a single-stage pump. However, the possibility of differential desorption as a first stage in the TSTA gas separation cycle required the inclusion of a first-stage hydrogen isotope condenser. The design, performance, and operating characteristics are discussed.

Batzer, T.H.; Patrick, R.E.; Call, W.R.

1980-08-18

337

Nitro musk compounds genotoxic activity  

Microsoft Academic Search

s  Five nitro musk compounds are widely used as fragrance ingredients in perfumes, lotions and detergents; as food additives\\u000a in cigarettes and fish baits, and in such technical products as herbicide formulations and explosives. Several studies identified\\u000a nitro musk compounds in aquatic environment samples, human milk and fat samples as highly lipophilic and persistent bioaccumulating\\u000a environmental pollutants. To examine the compounds

Sebastian Kevekordes; Kathrin Grahl; Antonia Zaulig; Hartmut Dunkelberg

1996-01-01

338

Chromatographic determination of phenylarsenic compounds  

Microsoft Academic Search

Gas chromatographic (GC) and liquid chromatographic methods for the investigation of phenylarsenic compounds are presented.\\u000a With gas chromatography using an electron capture detector (ECD), the chemical warfare agents PFIFFIKUS, CLARK I and CLARK\\u000a II can be detected. After derivatization with mercaptans and dimercaptans the sum of diphenylarsenic compounds resp. phenylarsenic\\u000a and phenylarsonic compounds can be detected as the mercapto resp.

R. Haas; Torsten C. Schmidt; Klaus Steinbach; Eberhard von Löw

1998-01-01

339

Method of preparing metallocene compounds  

DOEpatents

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

Rosenblum, Myron (Lexington, MA); Matchett, Stephen A. (Lisle, IL)

1992-01-01

340

Organic Compounds in Carbonaceous Meteorites  

NASA Technical Reports Server (NTRS)

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

Cooper, Grorge

2001-01-01

341

Indole Compounds Useful as Serotonin Selective Agents.  

National Technical Information Service (NTIS)

Novel indole compounds are disclosed. Also disclosed are methods for using the compounds to treat human and animal disease, pharmaceutical compositions of the compounds, and kits including the compounds.

B. Roth C. Morency G. Kumaran H. P. Sard L. Shuster

2005-01-01

342

Thermodynamics of hydrogen trapping in intermetallic compounds: application to LaNi/sub 5//H  

SciTech Connect

It has been observed for several intermetallic compound/H systems that deviations from Sieverts' law of ideal solubility occur which are in the opposite direction from the deviations from ideality which occur in pure metal/H systems. The principal source of nonideality on both types of interstitial solutions arises from the changes of the relative partial molar enthalpy of H/sub 2/ solution, ..delta..H/sub H/, with H content. The variations of ..delta..H/sub H/ with H content are, however, in the opposite directions for intermetallic/H and pure metal/H interstitial solutions. Relative partial molar entropies for solution of H/sub 2/ in the ..cap alpha..-phase of the LaNi/sub 5//H system are given at 298.2/sup 0/K. These have been determined from calorimetric determinations of ..delta..H/sub H/ and measurements of ..delta..G/sub H/ (=RT ln P/sub H/sub 2///sup 1/2/). The partial entropies show unusual extrema as a function of H content. A model based on trapping of H atoms is proposed which explains the variations of ..delta..H/sub H/ and ..delta..S/sub H/. Since the deviations from ideality arising from an increase of ..delta..H/sub H/ with H content seem to be limited to solids with at least two different ordered metal components, e.g., intermetallic compounds, it seems reasonable to assign the trapping sites to interstices which result from an interchange of metal atoms. This interchange may create interstices rich in those nearest-neighbor metal atoms which have the greatest affinity for H.

Flanagan, T.B.; Wulff, C.A.; Bowerman, B.S.

1980-09-01

343

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

USGS Publications Warehouse

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

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

1986-01-01

344

Morphological Dynamics in Compound Processing  

ERIC Educational Resources Information Center

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

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

2008-01-01

345

Polishing compound for plastic surfaces.  

National Technical Information Service (NTIS)

A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. T...

M. S. Stowell

1993-01-01

346

Compounds exhibiting an antibiotic activity  

US Patent & Trademark Office Database

The present invention relates to compounds having antibiotic activity which are obtained from body fluids of mollusks, namely of certain West-African snails, to therapeutic drugs comprising these compounds, and to the use thereof for the preparation of a therapeutic drug for controlling infectious pathogens in humans and animals.

2006-01-03

347

Iridoid compounds from Boschniakia rossica.  

PubMed

Four iridoid compounds were isolated from methanol extract of Boschniakia rossica by repeated column chromatography. Their structures were determined as boschnaloside (1), boschnarol (2), bosnarol methylether (3), and 7-deoxy 8-epiloganic acid (4), respectively. Compound 2, 3, and 4 were isolated for the first time from this plant. PMID:10071965

Yin, Z Z; Kim, H S; Kim, Y H; Lee, J J

1999-02-01

348

Devices for collecting chemical compounds  

DOEpatents

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

Scott, Jill R; Groenewold, Gary S

2013-12-24

349

[Phenolic compounds from Caesalpinia minax].  

PubMed

Fifteen compounds were obtained from the twigs and leaves of Caesalpinia minax. Their structures were identified as apigenin (1), 5,7,3',4'- tetrahydroxy-3-methoxyflavone (2), luteolin-5, 3 '-dimethyl-ether (3), thevetiaflavon (4), apigenin-7-O-beta-D-glucuronide (5), bonducellin (6), 7-hydroxy-3-( 4-hydroxybenzylidene )-chroman-4-one (7), 3-deoxysappanchalcone (8), 5-acetonyl-7-hydroxy-2-methyl chromone (9), 4-(trans)-acetyl-3,6,8-trihydroxy-3-methyl-dihydronaphthalenone (10), 4-(cis)-acetyl-3,6,8-trihydroxy-3-methyl-dihydronaphthalenone (11), vanillic acid (12), omega-hydroxypropioquaiacone (13), syringaresinol (14) and uracil (15). All compounds were isolated from C. minax for the first time. Compounds 1-14 were phenolic compounds and compounds 1-5, 9-13 and 15 were isolated from the genus Caesalpinia for the first time. PMID:23847948

Ma, Rui-Jing; Yang, Xun-Yun; Wang, Ji-Hua; Tang, Hong-Bo; Wang, Li-Qin

2013-04-01

350

Assimilation of Unusual Carbon Compounds  

NASA Astrophysics Data System (ADS)

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

Middelhoven, Wouter J.

351

Benzospiroalkene heterocyclic compounds  

US Patent & Trademark Office Database

Compounds of formula (I): ##STR1## in which: X represents --CH.sub.2 --, --(CH.sub.2).sub.2 --, --CH.dbd.CH--, --O--CH.sub.2 --, --S--CH.sub.2 --, --SO--CH.sub.2 -- or --SO.sub.2 --CH.sub.2 --, Y represents oxygen or sulfur or --NR.sub.6 --, R.sub.1 represents hydrogen or linear or branched (C.sub.1 -C.sub.6) alkyl, R.sub.2 represents hydrogen or halogen, linear or branched (C.sub.1 -C.sub.6) alkyl, (substituted or unsubstituted), hydroxyl, linear or branched (C.sub.1 -C.sub.6) alkoxy or linear or branched (C.sub.1 -C.sub.6) alkylthio, R.sub.3 represents hydrogen or halogen, linear or branched (C.sub.1 -C.sub.6) alkyl (substituted or unsubstituted), hydroxyl, linear or branched (C.sub.1 -C.sub.6) alkoxy or linear or branched (C.sub.1 -C.sub.6)alkylthio, R.sub.4 represents hydrogen (on condition that, in this case, R.sub.1 represents hydrogen), halogen, linear or branched (C.sub.1 -C.sub.6) alkyl (substituted or unsubstituted) or hydroxyl, or alternatively R.sub.1 and R.sub.2, R.sub.2 and R.sub.3, R.sub.3 and R.sub.4 or R.sub.4 and X, together with the carbon atoms which bear them, form a benzene ring, on condition that, in the case where R.sub.1 and R.sub.2 form a benzene ring, X is other than --CH.sub.2 -- or --(CH.sub.2).sub.2 --, R.sub.5 represents hydrogen or amino (substituted or unsubstituted), R.sub.6 has the same meaning as R.sub.1, their isomers and also their. addition salts with a pharmaceutically acceptable acid and medicinal product containing the sarne are useful as partial .alpha..sub.1 and .alpha..sub.2 adrenergic agonist in the treatment of venous disease and migraine.

1995-07-25

352

Membrane rejection of nitrogen compounds  

NASA Technical Reports Server (NTRS)

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

Lee, S.; Lueptow, R. M.

2001-01-01

353

Basics of compounding: basics of compounding with inorganic salts.  

PubMed

Pharmacists involved in compounding must consider a number of factors when determining the actual quantity of an active ingredient to use for a compounded prescription. Many drug substances do not consist of 100% drug or chemical, and adjustments must be made to obtain the required amount of active drug (active pharmaceutical ingredient). This is true with inorganic salts, the topic of this article, along with other factors related to physical and chemical properties of the salts that must also be considered. PMID:23696084

Allen, Loyd V

2011-01-01

354

Enzyme inhibiting compounds and methods  

US Patent & Trademark Office Database

The invention provides compounds, compositions, and methods for studying the Rohmer pathway and for treating bacterial infections or parasitic infections. The parasitic infection can be a protozoan infection, such as malaria. The compounds and compositions can also be used as antibiotics, for example, to kill bacteria or parasites, or to inhibit bacterial or parasite growth. The invention further provides inhibitors of isoprenoid biosynthesis enzymes, and methods of inhibiting the activity of isoprenoid biosynthesis enzymes. The compounds can be, for example, alkynes or allenes that bind to a unique Fe of an Fe4S4 cluster of an isoprenoid biosynthesis enzyme.

2013-12-17

355

Polishing compound for plastic surfaces  

DOEpatents

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

Stowell, M.S.

1993-01-01

356

Compound curvature laser window development  

NASA Technical Reports Server (NTRS)

The NASA Lewis Research Center has developed and implemented a unique process for forming flawless compound curvature laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report summarizes the main aspects of compound curvature laser window development. It is an overview of the methodology and the peculiarities associated with the formulation of these windows. Included in this discussion is new information regarding procedures for compound curvature laser window development.

Verhoff, Vincent G.

1993-01-01

357

Polishing compound for plastic surfaces  

DOEpatents

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

Stowell, Michael S. (New Ellenton, SC)

1995-01-01

358

Polishing compound for plastic surfaces  

DOEpatents

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

Stowell, M.S.

1995-08-22

359

The Magic of Compound Interest  

NSDL National Science Digital Library

The most powerful force in the universe is compound interest - Albert Einstein - Compound interest is the underlying concept that allows your money to grow on its own and that\\'s what leads to a lucrative future. It\\'s the interest you earn off of your original investment plus the interest you\\'ve already accrued. It\\'s interest on interest. And what it can do is amazing. Compound interest\\'s a cyclical monster that feeds itself and keeps growing at an exponential rate. And the best part about compound interest is that young people have the advantage. Young, first-time investors have an upper hand on older, wiser, Wall Street investors and stock market gurus because young people have ...

Gordon, Mr.

2006-10-19

360

Polishing compound for plastic surfaces  

DOEpatents

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

Stowell, M.S.

1991-01-01

361

Nitric Oxide-Releasing Compounds  

NSDL National Science Digital Library

The five WebWare Molecules for December derive from the article Nitrogen-Based Diazeniumdiolates: Versatile Nitric Oxide-Releasing Compounds for Biomedical Research and Potential Clinical Applications by Joseph E. Saavedra and Larry K. Keefer.

362

Adsorbent for Polynuclear Aromatic Compounds.  

National Technical Information Service (NTIS)

This patent application discusses an adsorbent composition comprising powdered charcoal on a support of polyurethane foam, and its use for separation of polynuclear aromatic compounds from mixtures containing them.

D. L. Stalling J. N. Huckins W. A. Smith

1976-01-01

363

Synthesis of Semiconducting Coordination Compounds.  

National Technical Information Service (NTIS)

New methods for the synthesis of superconducting phases are always needed. The authors therefore became interested in preparing superconducting binary compounds directly on wires through the thermal decomposition of volatile hydrides and organometallic co...

G. N. Schrauzer

1977-01-01

364

Cage-Like Silicon Compounds.  

National Technical Information Service (NTIS)

The factors influencing the formation of octaisopropylocta- silsesquioxane have been investigated. This compound can be brominated by means of N-bromosuccinimide. Chemical evidence and n.m.r. spectroscopy show that bromination occurs in the alpha position...

J. H. Bishop R. A. Shaw

1965-01-01

365

New Carbamates and Related Compounds.  

National Technical Information Service (NTIS)

The preparation of 19 N,N-dialkylaminoalkylanilinocarbamate hydrochlorides, N-phenyl-N-(phthalimidoalkyl)carbamoyl halides, and related compounds is reported. Ethyl N-(2-chloroethyl)-N-phenylcarbamate was distilled (80% yield) without decomposition to oxa...

B. H. Alexander C. J. Choi A. S. Prince M. H. Aldridge

1966-01-01

366

Compound Independent and Dependent Events  

NSDL National Science Digital Library

Compare the theoretical and experimental probability of a compound independent event by drawing colored marbles from a bag. Record the results of successive draws with or without replacement of marbles to calculate the experimental probability.

2007-12-12

367

Photoprotective compounds from marine organisms  

Microsoft Academic Search

The substantial loss in the stratospheric ozone layer and consequent increase in solar ultraviolet radiation on the earth’s\\u000a surface have augmented the interest in searching for natural photoprotective compounds in organisms of marine as well as freshwater\\u000a ecosystems. A number of photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin, carotenoids and\\u000a several other UV-absorbing substances of unknown chemical structure

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

2010-01-01

368

Volatile Compounds in Spanish Paprika  

Microsoft Academic Search

The volatile compounds extracted from both sweet and hot samples of commercial Spanish paprika were analyzed by gas chromatography\\/mass spectrometry (GC-MS). Sixty-one peaks were detected in the volatile extracts of which 55 were identified, only 24 were present in all four samples. The substances identified belonged to several chemical classes: phenols, aldehydes, acids, ketones, alcohols, ethers, nitrogen compounds, aromatic hydrocarbons,

Javier Mateo; Mercedes Aguirrezábal; Concepción Dom??nguez; José Mar??a Zumalacárregui

1997-01-01

369

Compound Constructions of Broadcast Networks  

Microsoft Academic Search

Compound methods have been shown to be very e#ective in the construction of broadcastgraphs. Compound methods generate a large broadcast graph by combining multiple copies ofa broadcast graph G using the structure of another broadcast graph H . Node deletion is alsoallowed in some of these methods. The subset of connecting nodes of G has been de#ned assolid h-cover by

Michael J. Dinneen; Jose A. Ventura; Mark C. Wilson; Golbon Zakeri

1999-01-01

370

Magnetic and thermodynamic properties of NdT{sub 2}Ge{sub 2} (T=Pd, Ag) compounds  

SciTech Connect

Physical properties of NdPd{sub 2}Ge{sub 2} and NdAg{sub 2}Ge{sub 2}, crystallizing with the tetragonal ThCr{sub 2}Si{sub 2}-type crystal structure, were investigated by means of magnetic, calorimetric, electrical transport as well as by neutron diffraction measurements. The specific heat studies and neutron diffraction measurements were performed down to 0.30 K and 0.47 K, respectively. Both compounds exhibit antiferromagnetic ordering below T{sub N} equal to 1.5 K for NdPd{sub 2}Ge{sub 2} and 1.8 K for NdAg{sub 2}Ge{sub 2}. Neutron diffraction data for the latter germanide indicate antiferromagnetic collinear structure described by the propagation vector k=(0.5, 0, 0.5). The Nd magnetic moments equal to 2.24(5) mu{sub B} at 0.47 K are aligned along the a-axis and have the +- sequence within the crystal unit cell. For NdPd{sub 2}Ge{sub 2} only very small Bragg peaks of magnetic origin were observed in the neutron diffraction patterns measured below T{sub N}, thus hampering determination of the magnetic structure. Both compounds exhibit metallic-like electrical conduction. From the specific heat data the crystal electric field (CEF) levels schemes were determined. Difference between the overall CEF splitting in the two compounds is correlated with their structural parameters. - Graphical abstract: Low-temperature specific heat of NdAg{sub 2}Ge{sub 2} under external magnetic fields. The lambda-like anomaly originates from onset of magnetic ordering below 1.80 K. Shifting the anomaly position towards the lower temperatures, when raising the magnetic field, hints at antiferromagnetic behaviors.

Gondek, L., E-mail: lgondek@agh.edu.p [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow (Poland); Penc, B. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland); Kaczorowski, D. [W. Trzebiatowski Institute of Low Temperature and Structural Research, Polish Academy of Sciences, PO Box 1410, 50-950 WrocLaw (Poland); Baran, S. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland); Hoser, A.; Gerischer, S. [BENSC, Helmholtz-Zentrum Berlin, Glienicker Str. 100, D-14 109 Berlin (Germany); SzytuLa, A. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow (Poland)

2010-04-15

371

Miniature curved artificial compound eyes  

PubMed Central

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

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

2013-01-01

372

Photoprotective compounds from marine organisms.  

PubMed

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

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

2010-06-01

373

Compounds with High Monoamine Transporter Affinity.  

National Technical Information Service (NTIS)

Featured compounds have high monoamine transport affinity and are characterized by one of the following two general formulas set out above. The compounds bind selectively or non-selectively to monoamine transporters. The compounds are useful to treat vari...

B. K. Madras P. Blundell P. Wang P. C. Meltzer

2005-01-01

374

Associative asymmetry of compound words.  

PubMed

Early verbal-memory researchers assumed participants represent memory of a pair of unrelated items with 2 independent, separately modifiable, directional associations. However, memory for pairs of unrelated words (A-B) exhibits associative symmetry: a near-perfect correlation between accuracy on forward (A??) and backward (??B) cued recall. This was viewed as arguing against the independent-associations hypothesis and in favor of the hypothesis that associations are remembered as holistic units. Here we test the Holistic Representation hypothesis further by examining cued recall of compound words. If we suppose preexisting words are more unitized than novel associations, the Holistic Representation hypothesis predicts compound words (e.g., ROSE BUD) will have a higher forward-backward correlation than novel compounds (e.g., BRIEF TAX). We report the opposite finding: Compound words, as well as noncompound words, exhibited less associative symmetry than novel compounds. This challenges the Holistic Representation account of associative symmetry. Moreover, preexperimental associates (positional family size) influenced associative symmetry-but asymmetrically: Increasing family size of the last constituent increasing decoupled forward and backward recall, but family size of the 1st constituent had no such effect. In short, highly practiced, meaningful associations exhibit associative asymmetry, suggesting associative symmetry is not diagnostic of holistic representations but, rather, is a characteristic of ad hoc associations. With additional learning, symmetric associations may be replaced by directional, independently modifiable associations as verbal associations become embedded within a rich knowledge structure. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:24773284

Caplan, Jeremy B; Boulton, Kathy L; Gagné, Christina L

2014-07-01

375

Cytotoxic Compounds from Brucea mollis  

PubMed Central

Ten compounds, including soulameanone (1), isobruceine B (2), 9-methoxy-canthin-6-one (3), bruceolline F (4), niloticine (5), octatriacontan-1-ol (6), bombiprenone (7), ?-tocopherol (8), inosine (9), and apigenin 7-O-?-D-glucopyranoside (10), were isolated from the leaves, stems, and roots of Brucea mollis Wall. ex Kurz. Their structures were determined using one-and two-dimensional NMR spectroscopy and mass spectrometry. All compounds were evaluated for their cytotoxic activity against KB (human carcinoma of the mouth), LU-1 (human lung adenocarcinoma), LNCaP (human prostate adeno-carcinoma), and HL-60 (human promyelocytic leukemia) cancer cell lines. Compound 2 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values of 0.39, 0.40, 0.34, and 0.23 ?g/mL, respectively. In addition, compounds 3 and 5 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values around 1–4 ?g/mL. Compounds 9-methoxycanthin-6-one (3) and niloticine (5) have been discovered for the first time from the Brucea genus.

Tung, Mai Hung Thanh; ?uc, Ho Viet; Huong, Tran Thu; Duong, Nguyen Thanh; Phuong, Do Thi; Thao, Do Thi; Tai, Bui Huu; Kim, Young Ho; Bach, Tran The; Cuong, Nguyen Manh

2013-01-01

376

Cytotoxic Compounds from Brucea mollis.  

PubMed

Ten compounds, including soulameanone (1), isobruceine B (2), 9-methoxy-canthin-6-one (3), bruceolline F (4), niloticine (5), octatriacontan-1-ol (6), bombiprenone (7), ?-tocopherol (8), inosine (9), and apigenin 7-O-?-D-glucopyranoside (10), were isolated from the leaves, stems, and roots of Brucea mollis Wall. ex Kurz. Their structures were determined using one-and two-dimensional NMR spectroscopy and mass spectrometry. All compounds were evaluated for their cytotoxic activity against KB (human carcinoma of the mouth), LU-1 (human lung adenocarcinoma), LNCaP (human prostate adeno-carcinoma), and HL-60 (human promyelocytic leukemia) cancer cell lines. Compound 2 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values of 0.39, 0.40, 0.34, and 0.23 ?g/mL, respectively. In addition, compounds 3 and 5 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values around 1-4 ?g/mL. Compounds 9-methoxycanthin-6-one (3) and niloticine (5) have been discovered for the first time from the Brucea genus. PMID:24106661

Tung, Mai Hung Thanh; Duc, Ho Viet; Huong, Tran Thu; Duong, Nguyen Thanh; Phuong, Do Thi; Thao, Do Thi; Tai, Bui Huu; Kim, Young Ho; Bach, Tran The; Cuong, Nguyen Manh

2012-01-01

377

Antimutagenic effects of polyphenolic compounds.  

PubMed

Smokers expose themselves to potent carcinogens daily. One of them is the nicotine-derived nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Since estimates are that humans consume 1 g of phenolic compounds/day, we investigated the inhibitory effects of five structurally related polyphenolic compounds on the mutagenicity of NNK in Salmonella typhimurium TA1535. NNK at a concentration of 80 mM was activated by hamster liver microsomes. The antimutagenic efficacies were dose-related between the non-toxic concentrations of 0.1 and 0.5 mmol/dish in the following order: esculetin > ellagic acid > (+)-catechin > propyl gallate > (-)esculin. At the highest non-toxic dose tested (0.5 mmol/dish), these polyphenolics inhibited mutagenesis in TA1535 by 77%, 67%, 62%, 59% and 53%, respectively. The results of this study demonstrated that polyphenolic compounds may inhibit the activation of NNK. PMID:1394114

Teel, R W; Castonguay, A

1992-09-30

378

Gallium-containing anticancer compounds  

PubMed Central

There is an ever pressing need to develop new drugs for the treatment of cancer. Gallium nitrate, a group IIIa metal salt, inhibits the proliferation of tumor cells in vitro and in vivo and has shown activity against non-Hodgkin’s lymphoma and bladder cancer in clinical trials. Gallium can function as an iron mimetic and perturb iron-dependent proliferation and other iron-related processes in tumor cells. Gallium nitrate lacks cross resistance with conventional chemotherapeutic drugs and is not myelosuppressive; it can be used when other drugs have failed or when the blood count is low. Given the therapeutic potential of gallium, newer generations of gallium compounds are now in various phases of preclinical and clinical development. These compounds hold the promise of greater anti-tumor activity against a broader spectrum of cancers. The development of gallium compounds for cancer treatment and their mechanisms of action will be discussed.

Chitambar, Christopher R

2013-01-01

379

Organometallic chemistry of bimetallic compounds  

SciTech Connect

Hydrogenation of alkynes by the heterobimetallic compound C{sub 5}H{sub 5}(CO){sub 2}Re({mu}-H)Pt(H)(PPh{sub 3}){sub 2} is being studied. The compound C{sub 5}Me{sub 5}(CO){sub 2}Re{double bond}Re(CO){sub 2}C{sub 5}Me{sub 5} was synthesized; its chemistry is being studied. Compounds discovered in a reinvestigation of a spurious report of (C{sub 5}Me{sub 5})Co{double bond}Co(C{sub 5}Me{sub 5}), are being studied. The deuterioformylation of alkenes using wide bite angle phosphines will be studied.

Casey, C.P.

1992-07-01

380

Basics of compounding with tars.  

PubMed

Tar has been used throughout history for numerous purposes; from sealing the hulls of ships to sealing roofs of dwellings and even for medical purposes. Produced by destructive distillation, commonly used tars are prepared from coal and wood. Coal tar, juniper tar, and pine tar are used for various medical purposes as described in the article. Also presented are the various characteristics and uses of each tar, along with commercial products and numerous compounding formulas. Techniques used to compound with tars are also presented. PMID:24459787

Allen, Loyd V

2013-01-01

381

Persulfate Oxidation of Gasoline Compounds  

NASA Astrophysics Data System (ADS)

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

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

2009-05-01

382

Infrared Spectroscopy of Deuterated Compounds.  

ERIC Educational Resources Information Center

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

MacCarthy, Patrick

1985-01-01

383

The valuation of compound options  

Microsoft Academic Search

can be generalized to value many corporate liabilities. The compound call option formula derived herein considers a call option on stock which is itself an option on the assets of the lirm. This perspective incorporates leverage effects into option pricing and consequently the variance of the rate of return on the stock is not constant as Black-&holes assumed, but is

Robert Geske

1979-01-01

384

Polyhdroxylated Benzene-Containing Compounds.  

National Technical Information Service (NTIS)

A method for reducing food intake in a subject and a method for reducing the levels of an endocrine in a subject. The methods include administering to the subject in need thereof an effective amount of a compound of the formula: Also disclosed is a liposo...

R. A. Hiipakka S. Liao Y. H. Kao

2003-01-01

385

Bioactive compounds from Peperomia pellucida.  

PubMed

Five new compounds (1-5), including two secolignans, two tetrahydrofuran lignans, and one highly methoxylated dihydronaphthalenone, were isolated from the whole plant of Peperomia pellucida. These compounds were accompanied by the known peperomins A, B, C, and E, 7,8-trans-8,8'-trans-7',8'-cis-7,7'-bis(5-methoxy-3,4-methylenedioxyphenyl)-8-acetoxymethyl-8'-hydroxymethyltetrahydrofuran, 7,8-trans-8,8'-trans-7',8'-cis-7-(5-methoxy-3,4-methylenedioxyphenyl)-7'-(4-hydroxy-3,5-dimethoxyphenyl)-8,8'-diacetoxymethyltetrahydrofuran, sesamin, and isoswertisin. New structures were elucidated mainly by NMR and MS techniques, and anticancer activities evaluated in HL-60, MCF-7, and HeLa cell lines. Compound 1 and peperomin E show growth inhibitory effects on the three cancer cell lines with IC(50) values ranging between 1.4 and 9.1 and between 1.8 and 11.1 microM, respectively. Compound 2 has a weak suppressive activity on HL-60 cells (IC(50) = 10.8 microM), while 7,8-trans-8,8'-trans-7',8'-cis-7,7'-bis(5-methoxy-3,4-methylenedioxyphenyl)-8-acetoxymethyl-8'-hydroxymethyltetrahydrofuran exhibits estrogen-like properties (EC(50) = 3.1 microM) in CV-1 cells transfected with human estrogen receptor (ERalpha). PMID:16499324

Xu, Su; Li, Na; Ning, Meng-Meng; Zhou, Cai-Hong; Yang, Qiao-Rong; Wang, Ming-Wei

2006-02-01

386

Preparation of Potential Antimalarial Compounds.  

National Technical Information Service (NTIS)

Satisfactory procedures were developed and samples were prepared of the following compounds: chloroacetone oxime, 1,4-bis(2-oximinopropyl)piperazine, 1,4-bis(2(7-chloro-4-quinolyamino)propyl) piperazine, 3,5-bis(1-pyrrolidinomethyl)-4-hydroxyacetanilide, ...

D. A. Warner

1966-01-01

387

Atmospheric Freons and Halogenated Compounds.  

National Technical Information Service (NTIS)

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

A. Appleby

1976-01-01

388

Polymeric nanocomposites: compounding and performance.  

PubMed

Polymeric nanocomposites (PNC) are binary mixtures of strongly interacting, inorganic platelets dispersed in a polymeric matrix. For full exfoliation, the thermodynamic miscibility is required. There are three basic methods of organically-modified clay dispersion that might result in PNC: (1) in polymer solution (followed by solvent removal), (2) in a monomer (followed by polymerization), and (3) in molten polymer (compounding). Most commercial PNC are produced by the second method, but it is the third one that has the greatest promise for the plastics industry. Similarly as during the manufacture of polymer blends, the layered silicates must be compatibilized by intercalation with organic salts and/or addition of functionalized macromolecules. Compounding affects the kinetics of dispersion process, but rarely the miscibility. Melt compounding is carried out either in a single-screw (SSE) or a twin-screw extruder (TSE). Furthermore, an extensional flow mixer (EFM) might be attached to an extruder. Two versions of EFM were evaluated: (1) designed for polymer homogenization and blending, and (2) designed for dispersing nano-particles. In this review, the dispersion of organoclay in polystyrene (PS), polyamide-6 (PA-6) or in polypropylene (PP) is discussed. The PNC based on PS or PA-6 contained two components (polymer and organoclay), whereas those based on PP in addition had a compatibilizer mixture of two maleated polypropylenes. Better dispersion was found compounding PNC's in a SSE + EFM than in TSE with or without EFM. The mechanical performance (tensile, flexural and impact) was examined. PMID:18572559

Utracki, L A

2008-04-01

389

Low volatile organic compound paints  

Microsoft Academic Search

Increasingly stringent air emission standards in various states has dictated the elimination of engineering finishes which are derived from high volatile organic compound (VOC) paint chemistries. In July 1989, Allied-Signal, Inc., Kansas City Division, Kansas City, Missouri, voluntarily closed its paint facility, due to non-compliance with local air emission standards. The following details the materials selection and evaluations which led

1991-01-01

390

Cancer prevention with natural compounds.  

PubMed

Botanical and nutritional compounds have been used for the treatment of cancer throughout history. These compounds also may be useful in the prevention of cancer. Population studies suggest that a reduced risk of cancer is associated with high consumption of vegetables and fruits. Thus, the cancer chemopreventive potential of naturally occurring phytochemicals is of great interest. There are numerous reports of cancer chemopreventive activity of dietary botanicals, including cruciferous vegetables such as cabbage and broccoli, Allium vegetables such as garlic and onion, green tea, Citrus fruits, soybeans, tomatoes, berries, and ginger, as well as medicinal plants. Several lead compounds, such as genistein (from soybeans), lycopene (from tomatoes), brassinin (from cruciferous vegetables), sulforaphane (from asparagus), indole-3-carbinol (from broccoli), and resveratrol (from grapes and peanuts) are in preclinical or clinical trials for cancer chemoprevention. Phytochemicals have great potential in cancer prevention because of their safety, low cost, and oral bioavailability. In this review, we discuss potential natural cancer preventive compounds and their mechanisms of action. PMID:20709209

Gullett, Norleena P; Ruhul Amin, A R M; Bayraktar, Soley; Pezzuto, John M; Shin, Dong M; Khuri, Fadlo R; Aggarwal, Bharat B; Surh, Young-Joon; Kucuk, Omer

2010-06-01

391

Thermodynamic Properties of K 2U 4O 12( s) and K 2U 4O 13( s) by EMF and Calorimetric Measurements  

NASA Astrophysics Data System (ADS)

The coexistence of K 2U 4O 12( s) and K 2U 4O 13( s) in the K-U-O system up to 1200 K was established. The EMF measurements over the above phase field were carried out using a calcia-stabilized zirconia solid electrolyte galvanic cell in the temperature range 1053 to 1222 K. The equilibrium oxygen partial pressure above the phase fields was calculated to be ln p(O 2) kPa±0.09=-31452/ T+25.065. The enthalpy increment values of K 2U 4O 12( s) and K 2U 4O 13( s) were measured using a high temperature Calvet calorimeter by drop method and the thermodynamic values were suggested for the compounds.

Iyer, V. S.; Jayanthi, K.; Venugopal, V.

1997-09-01

392

Large Constituent Families Help Children Parse Compounds  

ERIC Educational Resources Information Center

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

Krott, Andrea; Nicoladis, Elena

2005-01-01

393

Compounding errors in 2 dogs receiving anticonvulsants  

PubMed Central

Two cases that involve drug compounding errors are described. One dog exhibited increased seizure activity due to a compounded, flavored phenobarbital solution that deteriorated before the expiration date provided by the compounder. The other dog developed clinical signs of hyperkalemia and bromine toxicity following a 5-fold compounding error in the concentration of potassium bromide (KBr).

McConkey, Sandra E.; Walker, Susan; Adams, Cathy

2012-01-01

394

Basics of compounding: basics of compounding with organic salts.  

PubMed

The purity and form of all ingredients used in compounding, especially of active pharmaceutical ingredients, must be known and considered during formulation. When a prescription is received, it is the responsibility of the pharmacist, and should be routine procedure, to correctly determine whether or not the salt or base/acid form of a drug is to be used as the basis for the dose. This is important information because the bulk substance, or active pharmaceutical ingredient, in a salt form is not 100% active drug. The purpose of the salt form is usually to enhance the solubility of the drug, but it may also enhance and change other attributes of the drug that make it easier to handle and manipulate for producing dosage forms. Resources for the purpose of determining this information include the United States Pharmacopeia, product package insert, and a call to the manufacturer or physician as appropriate. This article discusses compounding with salts and the factors that may affect a final compounded preparation. PMID:23965540

Allen, Loyd V

2010-01-01

395

Bacterial degradation of aromatic compounds.  

PubMed

Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms. PMID:19440284

Seo, Jong-Su; Keum, Young-Soo; Li, Qing X

2009-01-01

396

Alkylation of organic aromatic compounds  

DOEpatents

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

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

1994-06-14

397

Alkylation of organic aromatic compounds  

DOEpatents

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

Smith, Jr., Lawrence A. (Bellaire, TX); Arganbright, Robert P. (Seabrook, TX); Hearn, Dennis (Houston, TX)

1994-01-01

398

Alkylation of organic aromatic compounds  

DOEpatents

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

Smith, Jr., Lawrence A. (Bellaire, TX); Arganbright, Robert P. (Seabrook, TX); Hearn, Dennis (Houston, TX)

1993-01-01

399

Alkylation of organic aromatic compounds  

DOEpatents

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

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

1993-09-07

400

Global Warming Molecules: Fluorinated Compounds  

NASA Astrophysics Data System (ADS)

Two important properties quantitating the ability of a molecule to perturb global climate is the ability of the molecule to absorb infrared radiation in the atmospheric window (radiative forcing) and the amount of time that the molecule is in the atmosphere absorbing (atmospheric lifetime). Species in the atmosphere differ markedly in their ability to absorb infrared radiation. Greenhouse gases absorb terrestrial radiation in specific wavelength bands determined by the quantum mechanical properties of the specific molecule. In this talk we show that fluorinated compounds, including perfluorocarbons, possess all of the molecular requirements leading to vibrational bands that absorb in the atmospheric window and have very large IR intensities. Moreover, these compounds generally have long atmospheric lifetimes due to their low reactivity with OH radical.

Lee, Timothy; Francisco, Joseph

2004-03-01

401

Bacterial Degradation of Aromatic Compounds  

PubMed Central

Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

Seo, Jong-Su; Keum, Young-Soo; Li, Qing X.

2009-01-01

402

Thermal conductivity of cerium compounds  

SciTech Connect

The third-order perturbation-theory thermal conductivity is computed in the framework of the effective exchange Hamiltonian which describes both the resonant-scattering character and the crystalline field effect of cerium. The model is applied to the thermal conductivity measurements of cerium compounds and good agreement is found for CeAl/sub 2/ and CeCu/sub 2/Si/sub 2/.

Bhattacharjee, A.K.; Coqblin, B.

1988-07-01

403

Synthesis of Fluorinated ZDDP Compounds  

Microsoft Academic Search

Volatile degradation products of zinc dialkyl dithio phosphate (ZDDP) composed of phosphorus and sulfur compounds reduce the\\u000a efficiency of catalytic converters resulting in harmful emissions. A unique way of reducing ZDDP level while maintaining good\\u000a antiwear performance has been achieved by reacting a novel additive FeF3 with ZDDP. The objective of this research is to examine the chemical interactions between

Kajal Parekh; Xin Chen; Pranesh B. Aswath

2009-01-01

404

Compounds That Promote Seed Germination  

NSDL National Science Digital Library

The two molecules for this month come from the section Compound in Smoke Provides the Spark for Germination in the article about "Research Advances" by Angela G. King. These molecules have been demonstrated to stimulate seed germination under various conditions. The butenolide moiety is frequently encountered in natural products. An interesting approach to the synthesis of such molecules can be found in this Organic Letters article (accessed January 2005).

405

Arsenic compounds as anticancer agents  

Microsoft Academic Search

In this paper the use of arsenic compounds as anticancer agents in clinical trials and in in vitro investigations is reviewed, including the experience at our institute. Treatment of newly diagnosed and relapsed patients with acute promyelocytic leukemia (APL) with arsenic trioxide (As2O3) has been found to result in complete remission (CR) rates of 85-93% when given by intravenous infusion

Zhen-Yi Wang

2001-01-01

406

Artificial compound eye zoom camera.  

PubMed

We demonstrate a highly compact image capturing system with variable field of view but without any mechanically moving parts. The camera combines an ultra-thin artificial apposition compound eye with one variable focal length liquid lens. The change of optical power of the liquid lens when applying a voltage results in a change of the magnification of the microlens array imaging system. However, its effect on focusing of the individual microlenses can be neglected due to their small focal length. PMID:19029582

Duparré, Jacques; Wippermann, Frank; Dannberg, Peter; Bräuer, Andreas

2008-12-01

407

Catalytic Rearrangement of Epoxide Compounds  

Microsoft Academic Search

Products formed by rearrangement of epoxide compounds provide useful intermediates in organic syntheses and some of them are valuable as raw materials in the chemical industry. Many studies on the catalytic rearrangement of the epoxides have been made. The reactions which have been used most frequently are homogeneous with acid or base catalysts such as BF3, MgBr2, t-BuOK, or lithium

K. Arata; K. Tanabe

1983-01-01

408

Antibacterial compounds from Zanthoxylum rhetsa.  

PubMed

A new amide, zanthorhetsamide (1), along with nine known compounds (2-10) was isolated from the roots and stem barks of Zanthoxylum rhetsa. The structure was characterized by spectroscopic methods. In addition, the antibacterial activity of the isolates was evaluated. Dihydrochelerythrine (4) exhibited strong activity against methicillin-resistant Staphylococcus aureus SK1 and moderate activity against Escherichia coli TISTR 780 with MIC values of 8 and 16 ?g/mL, respectively. PMID:22864735

Tantapakul, Cholpisut; Phakhodee, Wong; Ritthiwigrom, Thunwadee; Yossathera, Kulsiri; Deachathai, Suwanna; Laphookhieo, Surat

2012-07-01

409

TRP Modulation by Natural Compounds.  

PubMed

The use of medicinal plants or other naturally derived products to relieve illness can be traced back over several millennia, and these natural products are still extensively used nowadays. Studies on natural products have, over the years, enormously contributed to the development of therapeutic drugs used in modern medicine. By means of the use of these substances as selective agonists, antagonists, enzyme inhibitors or activators, it has been possible to understand the complex function of many relevant targets. For instance, in an attempt to understand how pepper species evoke hot and painful actions, the pungent and active constituent capsaicin (from Capsicum sp.) was isolated in 1846 and the receptor for the biological actions of capsaicin was cloned in 1997, which is now known as TRPV1 (transient receptor potential vanilloid 1). Thus, TRPV1 agonists and antagonists have currently been tested in order to find new drug classes to treat different disorders. Indeed, the transient receptor potential (TRP) proteins are targets for several natural compounds, and antagonists of TRPs have been synthesised based on the knowledge of naturally derived products. In this context, this chapter focuses on naturally derived compounds (from plants and animals) that are reported to be able to modulate TRP channels. To clarify and make the understanding of the modulatory effects of natural compounds on TRPs easier, this chapter is divided into groups according to TRP subfamilies: TRPV (TRP vanilloid), TRPA (TRP ankyrin), TRPM (TRP melastatin), TRPC (TRP canonical) and TRPP (TRP polycystin). A general overview on the naturally derived compounds that modulate TRPs is depicted in Table 1. PMID:24961985

Meotti, Flavia Carla; Lemos de Andrade, Edinéia; Calixto, João B

2014-01-01

410

[Genotoxic effects of vanadium compounds].  

PubMed

Vanadium is a metal member of the periodic table VB group, with atomic weight 59.95 and atomic number 23 and it has some oxidizing states from -1 to +5. Vanadium has many industrial uses and its contribution with environmental contamination is growing every day. In the last 10 years research about the vanadium effects on living beings, has been increasing substantially, due to its presence in the environment from different sources. Interest for vanadium and their compounds is because its toxic effects and uses in some biomedical areas: such as antineoplastic, cholesterol and glucose level blood, diuretic, oxygen haemoglobin affinity. Vanadium toxic effects are so due to the fact of its property of inhibiting many enzymatic systems. Vanadate and vanadyl ions make chemical complexes exhibiting the property of inhibiting or increasing the activity of the enzymes participating in the DNA and RNA synthesis. They also induce mutagenic and genotoxic effects. Biochemical assays show cytotoxic effects, increase in the cellular differentiation, gene expression alterations and other biochemical and metabolic alterations. Research has been done with in vitro systems, but few with laboratory animals. It is necessary to carry out more work in the field of genetic toxicology with vanadium compounds. This type of compounds may be considered mutagenic and genotoxic, with cytotoxic and aneuploidogenous effects. PMID:9650459

Altamirano-Lozano, M

1998-04-01

411

Hydrogen storage in molecular compounds  

PubMed Central

At low temperature (T) and high pressure (P), gas molecules can be held in ice cages to form crystalline molecular compounds that may have application for energy storage. We synthesized a hydrogen clathrate hydrate, H2(H2O)2, that holds 50 g/liter hydrogen by volume or 5.3 wt %. The clathrate, synthesized at 200–300 MPa and 240–249 K, can be preserved to ambient P at 77 K. The stored hydrogen is released when the clathrate is warmed to 140 K at ambient P. Low T also stabilizes other molecular compounds containing large amounts of molecular hydrogen, although not to ambient P, e.g., the stability field for H2(H2O) filled ice (11.2 wt % molecular hydrogen) is extended from 2,300 MPa at 300 K to 600 MPa at 190 K, and that for (H2)4CH4 (33.4 wt % molecular hydrogen) is extended from 5,000 MPa at 300 K to 200 MPa at 77 K. These unique characteristics show the potential of developing low-T molecular crystalline compounds as a new means for hydrogen storage.

Mao, Wendy L.; Mao, Ho-kwang

2004-01-01

412

Calorimetric and spectroscopic evidence of chain-melting in smectic E and smectic A phases of 4-alkyl-4'-isothiocyanatobiphenyl (nTCB).  

PubMed

To confirm the molten state of the alkyl chain in soft crystalline phase, smectic E (SmE) phase, thermodynamic and spectroscopic analyses were performed on 4-n-alkyl-4'-isothiocyanatobiphenyl (nTCB, n: the number of carbon atoms in the alkyl group). DSC results of 11TCB and 12TCB, having extra smectic A phase besides smectic E phase, show that their chain-length dependence of entropies of transition (?(trs)S) from the ordered crystalline (OC) phase to the SmE phase matches the trend found for nTCB (n = 4-10), while no chain-length dependence is observed in ?(trs)S at the SmE-to-SmA and SmA-to-isotropic liquid (IL) phase transitions in 11TCB and 12TCB. Temperature dependences of FT-IR spectra of six compounds (n = 2, 3, 5, 8, 10, and 12) were recorded. The CH stretching modes of the chain exhibited more pronounced change at the transition from the OC to the SmE phase than at the transition from the SmE phase to the IL or SmA phase. These results indicate that the alkyl chain is molten in the SmE phase as in IL. The disordering process of nTCB molecules from the OC to IL via anisotropic mesophases is discussed in terms of entropy. PMID:22765025

Yamamura, Yasuhisa; Adachi, Takuya; Miyazawa, Takahito; Horiuchi, Katsuya; Sumita, Masato; Massalska-Arod?, Maria; Urban, Stanis?aw; Saito, Kazuya

2012-08-01

413

Bioactive compounds from northern plants.  

PubMed

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

Hohtola, Anja

2010-01-01

414

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

NASA Astrophysics Data System (ADS)

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

Do??ga, Diana; Mikuli, Edward; Inaba, Akira; Górska, Natalia; Ho?derna-Natkaniec, Krystyna; Nitek, Wojciech

2013-01-01

415

Butein is a novel anti-adipogenic compound[S  

PubMed Central

Rhus verniciflua Stokes (RVS) has been used as a traditional herbal medicine for its various biological activities including anti-adipogenic effects. Activity-guided separation led to the identification of the anti-adipogenic functions of butein. Butein, a novel anti-adipogenic compound, robustly suppressed lipid accumulation and inhibited expression of adipogenic markers. Molecular studies showed that activated transforming growth factor-? (TGF-?) and suppressed signal transducer and activator of transcription 3 (STAT3) signaling pathways were mediated by butein. Analysis of the temporal expression profiles suggests that TGF-? signaling precedes the STAT3 in the butein-mediated anti-adipogenic cascade. Small interfering RNA-mediated silencing of STAT3 or SMAD2/3 blunted the inhibitory effects of butein on adipogenesis indicating that an interaction between two signaling pathways is required for the action of butein. Upon butein treatments, stimulation of TGF-? signaling was still preserved in STAT3 silenced cells, whereas regulation of STAT3 signaling by butein was significantly impaired in SMAD2/3 silenced cells, further showing that TGF-? acts upstream of STAT3 in the butein-mediated anti-adipogenesis. Taken together, the present study shows that butein, a novel anti-adipogenic compound from RVS, inhibits adipocyte differentiation through the TGF-? pathway followed by STAT3 and peroxisome proliferator-activated receptor ? signaling, further implicating potential roles of butein in TGF-?- and STAT3-dysregulated diseases.

Song, No-Joon; Yoon, Hyang-Jin; Kim, Ki Hyun; Jung, So-Ra; Jang, Woo-Seok; Seo, Cho-Rong; Lee, Young Min; Kweon, Dae-Hyuk; Hong, Joung-Woo; Lee, Jeong-Soo; Park, Ki-Moon; Lee, Kang Ro; Park, Kye Won

2013-01-01

416

Sibling and Independent Compound Chondrules  

NASA Astrophysics Data System (ADS)

We studied compound chondrules in 79 cm2 of ordinary chondrite (OC) thin sections. Compound chondrules consist of a primary that solidified first and one or more secondaries attached to the primary. Sibling compound chondrules have very similar textures and compositions; most, perhaps all, seem to consist of chondrules melted in the same heating event. About 1.4% of all chondrules are the primaries of sibling compound chondrules. A smaller fraction, 1.0%, of all chondrules are the primaries of independent chondrules, the members of which were melted in separate heating events. Independent chondrules show appreciable differences in texture and/or composition. We propose that sibling chondrules originated when numerous chondrules were created from one large, more-or-less homogeneous, precursor assemblage that was flash-melted to produce a large set (perhaps 100-1000) of chondrules; some of these collided while molten, probably within several centimeters of the production site. We envision that small radial velocities were imparted to the members of the set, with small differences in velocity causing collisions among those few in intersecting trajectories. If all chondrules were produced this way, the collision efficiency was 1.4%; if only 10% were produced in this fashion, the efficiency rises to 14%. The original Gooding-Keil model of independent compound chondrule formation calls for random collisions to occur while the secondaries were molten. This appears improbable because the mean period between collisions in the dusty midplane of the nebula is estimated to be hours (or days), orders of magnitude longer than the period during which chondrules could have retained low viscosities following a flash-heating event in a cool (<700 K) nebula. We suggest that most independent compound chondrules formed by the mechanism that accounts for chondrules with relict grains and for chondrules with coarse- grained rims: the primary chondrule was embedded in a porous dust assemblage at the time of the second heating event; it experienced minimal melting because melting efficiency increases with increasing surface/volume ratio. There is a minor tendency for the FeO/(FeO+MgO) ratio in independent secondaries to be higher than in primaries, as expected if this ratio increased with time in the nebular dust. However, Monte Carlo calculations confirm that the compositions of independent secondaries are not randomly distributed, but related to those of primaries. Some exchange probably occurred during the fusion of the two chondrules, but this mechanism seems unable to account for the general similarity of independent primary/secondary compositions. This suggests that, in the environment where, at any one time, chondrules were forming (perhaps the interface between the gaseous nebula and the dusty midplane), the dust composition was more uniform than it was in the central midplane at a later time when agglomeration occurred.

Wasson, J. T.; Krot, A. N.; Rubin, A. E.

1993-07-01

417

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

PubMed Central

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

Sartor, G; Hallbrucker, A; Mayer, E

1995-01-01

418

Antimalarial compounds from Parinari capensis.  

PubMed

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

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

2002-08-19

419

Basics of compounding with balsams.  

PubMed

Balsams have been used in pharmacy for centuries for many different purposes. Balsams include benzoin, Peruvian balsam, storax, and tolu balsam. Balsams are aromatic and usually oily resinous substances flowing from various plants and generally containing some amount of benzoic or cinnamic acid. Historically, they have been used orally and topically in various formulations. Today, their primary use is topically in solutions, ointments, creams, and lotions. Today, the most common use would be in diaper ointments and to treat various skin disorders. Pharmacists are still called upon to compound various preparations using balsams. PMID:24579300

Allen, Loyd V

2013-01-01

420

BBC Bitesize: Compounds and Mixtures  

NSDL National Science Digital Library

This animated tutorial for grades 6-9, published by the British Broadcasting Corporation, explores the molecular basis of compounds and mixtures. It is written in "bite-size" pieces so that adolescent learners can grasp the concepts more easily and connect information with prior knowledge. Each page is supplemented with audio narration and illustrations. Learners will try to fuse or separate elements, giving them insight into the bonding process without introducing advanced vocabulary. They will also view animations of filtration and evaporation. The tutorial ends with a brief quiz that allows students to self-test their understanding.

Bitesize, General C.

2011-06-27

421

Pharmaceutical Compounds Studied Using NEXAFS  

NASA Astrophysics Data System (ADS)

Total Electron Yield (TEY) oxygen K-edge NEXAFS detects the presence of strongly adsorbed water molecules on poloxamer-coated pharmaceutical actives, which provides a useful spectroscopic indicator for bioavailability. The results are supported by complementary XPS measurements. Carbon K-edge spectra obtained in a high-pressure NEXAFS cell were used in situ to establish how a polymer coating spread on a drug surface by using humidity induced dispersion of the coating. Finally, we demonstrate how combined Carbon and Oxygen K-edge measurements can be used to characterize amorphous surface layers on micronised crystals of a drug compound.

Murray Booth, A.; Braun, Simon; Lonsbourough, Tom; Purton, John; Patel, Sunil; Schroeder, Sven L. M.

2007-02-01

422

Volatile organic compound sensor system  

DOEpatents

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

Schabron, John F. (Laramie, WY); Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Waxahachie, TX); Sorini-Wong, Susan S. (Laramie, WY); Wong, Gregory K. (Laramie, WY)

2011-03-01

423

Volatile organic compound sensor system  

DOEpatents

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

Schabron, John F. (Laramie, WY) [Laramie, WY; Rovani, Jr., Joseph F. (Laramie, WY); Bomstad, Theresa M. (Laramie, WY) [Laramie, WY; Sorini-Wong, Susan S. (Laramie, WY) [Laramie, WY

2009-02-10

424

Fate and Effects of Organotin Compounds.  

National Technical Information Service (NTIS)

The need for research on environmental effects will grow concomitant with increasing use of organotin compounds. Because the potential number of synthesizable compounds is enormous, quantitative structure-activity relationships (QSAR) appear to be the mos...

R. B. Laughlin O. Linden

1985-01-01

425

Synthesis of Vinblastine, Vincristine and Related Compounds.  

National Technical Information Service (NTIS)

The patent application relates to an improved method particularly for producing dimer alkaloid compounds especially of the Vinca alkaloid group and in particularly is an improved method for producing the antiviral, antileukemic compounds vincristine and v...

J. P. Kutney

1975-01-01

426

Monolayer-Forming Substituted Phthalocyanine Compounds.  

National Technical Information Service (NTIS)

This invention relates general to phthalocyanine compounds, and more particularly to the preparation of aryloxy, arylthio, alkyloxy, and alkylthio phthalocyanine compounds and their subsequent incorporation into semiconducting thin films by the Langmuir-B...

W. R. Barger N. L. Jarvis A. W. Snow H. Wohltjen

1985-01-01

427

Sulfur Compounds in Comets. (Abstract Only)  

National Technical Information Service (NTIS)

Cometary atmospheres exhibit abundant sulfur and sulfur compounds, which are absent in planetary atmospheres. Sulfur compounds were also detected in interstellar media, including SO, SO2, CS, etc., but excluding S2 which was identified only in IRAS-Araki-...

S. Kim M. Ahearn

1989-01-01

428

Compound Sums and Their Applications in Finance.  

National Technical Information Service (NTIS)

Compound sums arise frequently in insurance (total claim size in a portfolio) and in accountancy (total error amount in audit populations). As the normal approximation for compound sums usually performs very badly, one may look for better methods for appr...

B. Tarigan R. Helmers

2003-01-01

429

Injection Molding Compound for Electromagnetic Shielding.  

National Technical Information Service (NTIS)

A thermoplastic injection molding compound with excellent electromagnetic shielding effectiveness has been developed as a material for housings of electronic equipment. The compound contains stainless steel fiber as an electroconductive filler and maintai...

H. Takahama H. Tamaki T. Herai

1988-01-01

430

Mercury Compounds in Drugs and Food.  

National Technical Information Service (NTIS)

The Food and Drug Administration (FDA) is required to: (1) compile a list of drugs and foods that contain intentionally introduced mercury compounds, and (2) provide a quantitative and qualitative analysis of the mercury compounds in this list. The agency...

1999-01-01

431

The Chemistry of Highly Fluorinated Compounds  

NSDL National Science Digital Library

The featured molecules for January come from the paper Fluorous Compounds and Their Role in Separation Chemistry by Maria Angeles Ubeda and Roman Dembinski. This paper explores the use of highly fluorinated compounds as solvents, catalysts, and reagents.

432

Survey of Phenolic Compounds Produced in Citrus.  

National Technical Information Service (NTIS)

A survey of phenolic compounds, especially flavanones and flavone and flavonol compounds, using high pressure liquid chromatography was performed in Rutaceae, subfamily Aurantiodeae, representing 5 genera, 35 species, and 114 cultivars. The average number...

M. Berhow B. Tisserat K. Kanes C. Vandercook

1998-01-01

433

Hyperpolarizable compounds and devices fabricated therefrom  

DOEpatents

Substituted compounds having relatively large molecular first order hyperpolarizabilities are provided, along with devices and materials containing them. In general, the compounds bear electron-donating and electron-withdrawing chemical substituents on a polyheterocyclic core. 13 figs.

Therien, M.J.; DiMagno, S.G.

1998-07-21

434

A new compound from Gastrodia elata blume  

Microsoft Academic Search

A new compound, f; -acetylamino-phenylprophyl f; -benzoylamino-phenylpropionate ( 1 ) and a known compound 4-hydroxybenzyl g; -sitosterol ether ( 2 ), were isolated from the tubers of Gastrodia elata Blume and their structures were elucidated by spectral data.

Yong-Qing Xiao; Li Li; Xiao-Lin You; Bao-Lin Bian; Xin-Miao Liang; Yi-Tao Wang

2002-01-01

435

5-Aryltertrazoles Compounds and Compositions Thereof.  

National Technical Information Service (NTIS)

The present invention relates to 5-Aryltetrazole Compounds, compositions comprising an effective amount of a a 5-Aryltetrazole Compound, and methods for treating an inflammation disease, a reperfusion disease, or hyperuricemia in an animal in need thereof...

A. Nivorozhkin G. Southan J. V. Duzer Q. Zeng S. Ram

2005-01-01

436

5-Aryltetrazole Compounds and Uses Thereof.  

National Technical Information Service (NTIS)

The present invention relates to 5-Aryltetrazole Compounds, compositions comprising an effective amount of a a 5-Aryltetrazole Compound, and methods for treating an inflammation disease, a reperfusion disease, or hyperuricemia in an animal in need thereof...

A. Nivorozhkin A. Salzman G. Southan J. V. Duzer Q. Zeng S. Ram

2005-01-01

437

Rubber compounding in the rubber processing industry.  

National Technical Information Service (NTIS)

This booklet in the Good Practice Guide Series is aimed at rubber compounders in the rubber processing industry. Its purpose is to encourage compounders to investigate more closely the possibilities for reducing energy consumption in a cost effective way....

1993-01-01

438

Compound Interest to e and i  

NSDL National Science Digital Library

Graphing and exploring simple interest and compound interest. Examples of interest earned on one dollar at 6 percent compounded daily, monthly, quarterly, annually. Patterns, infinite sequence. Sample problems with some answers from Chapter 11 of Don Cohen's worksheet book.

Cohen, Donald, 1939-

2007-04-08

439

Purification of gas with liquid ionic compounds  

US Patent & Trademark Office Database

The present invention provides a method for purifying a gas by contacting the gas with a liquid ionic compound. Natural gas may be purified, removing water and carbon dioxide, by contacting the natural gas with a liquid ionic compound.

2003-06-17

440

Studies of the structure and organization of cationic lipid bilayer membranes: calorimetric, spectroscopic, and x-ray diffraction studies of linear saturated P-O-ethyl phosphatidylcholines.  

PubMed Central

Differential scanning calorimetry, x-ray diffraction, and infrared and (31)P-nuclear magnetic resonance ((31)P-NMR) spectroscopy were used to examine the thermotropic phase behavior and organization of cationic model membranes composed of the P-O-ethyl esters of a homologous series of n-saturated 1,2-diacyl phosphatidylcholines (Et-PCs). Differential scanning calorimetry studies indicate that on heating, these lipids exhibit single highly energetic and cooperative endothermic transitions whose temperatures and enthalpies are higher than those of the corresponding phosphatidylcholines (PCs). Upon cooling, these Et-PCs exhibit two exothermic transitions at temperatures slightly below the single endotherm observed upon heating. These cooling exotherms have both been assigned to transitions between the liquid-crystalline and gel phases of these lipids by x-ray diffraction. The x-ray diffraction data also show that unlike the parent PCs, the chain-melting phase transition of these Et-PCs involves a direct transformation of a chain-interdigitated gel phase to the lamellar liquid-crystalline phase for the homologous series of n > or = 14. Our (31)P-NMR spectroscopic studies indicate that the rates of phosphate headgroup reorientation in both gel and liquid-crystalline phases of these lipids are comparable to those of the corresponding PC bilayers. However, the shape of the (31)P-NMR spectra observed in the interdigitated gel phase indicates that phosphate headgroup reorientation is subject to constraints that are not encountered in the non-interdigitated gel phases of parent PCs. The infrared spectroscopic data indicate that the Et-PCs adopt a very compact form of hydrocarbon chain packing in the interdigitated gel phase and that the polar/apolar interfacial regions of these bilayers are less hydrated than those of corresponding PC bilayers in both the gel and liquid-crystalline phases. Our results indicate that esterification of PC phosphate headgroups results in many alterations of bilayer physical properties aside from the endowment of a positively charged surface. This fact should be considered in assessing the interactions of these compounds with naturally occurring lipids and with other biological materials.

Lewis, R N; Winter, I; Kriechbaum, M; Lohner, K; McElhaney, R N

2001-01-01

441

Group IB Organometallic Chemistry. XVI. Complex formation between 2-(dimethy- lamino)phenylcopper with copper(I) or silver halides. Synthesis and structural characterization of hexanuclear (2Me2NC6H4)4Cu6-nMnX2 (M = Cu or Ag) cluster compounds  

Microsoft Academic Search

The 21 complexes (2RCu . MX) between 2-(dimethylamino)phenylcopper (RCu) and CuX (X = Cl, Br or I) or AgBr have been prepared in two ways (i) from the 23 reaction of 2-(dimethylamino)phenyllithium with cuprous halide and (ii) from the reaction of RCu with excess of the metalIB halide.The structure of bis[(2-dimethylamino)phenylcopper] cuprous bromide, which is dimeric (R{4}Cu{6}Br{2}) in the solid

G. van Koten; J. G. Noltes

1975-01-01

442

The Modification of Compounds by Attributive Adjectives  

ERIC Educational Resources Information Center

This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun…

Berg, Thomas

2011-01-01

443

Compound words and structure in the lexicon  

Microsoft Academic Search

The structure of lexical entries and the status of lexical decomposition remain controversial. In the psycholinguistic literature, one aspect of this debate concerns the psychological reality of the morphological complexity difference between compound words (teacup) and single words (crescent). The present study investigates morphological decomposition in compound words using visual lexical decision with simultaneous magnetoencephalography (MEG), comparing compounds, single words,

Robert Fiorentino; David Poeppel

2007-01-01

444

Biologically active compounds of semi-metals  

Microsoft Academic Search

Semi-metals, viz. boron, silicon, arsenic, selenium, tellurium and astatine form organo-metal compounds, some of which are found in nature and have striking effects on the physiology of living organisms. Representatives of these compounds are, e.g., four boron-containing antibiotics (aplasmomycin, borophycin, boromycin, and tatrolon). Silicon compounds, frequently present in \\

T. ?ezanka; K. Sigler

2008-01-01

445

Quantum Monte Carlo calculations on positronium compounds  

Microsoft Academic Search

The stability of compounds containing one or more positrons in addition to electrons and nuclei has been the focus of extensive scientific investigations. Interest in these compounds stems from the important role they play in the process of positron annihilation, which has become a useful technique in material science studies. Knowledge of these compounds comes mostly from calculations which are

Nan Jiang

1999-01-01

446

On Homology of Arthropod Compound Eyes  

Microsoft Academic Search

SYNOPSIS. Eyes serve as models to understand the evolution of complex traits, with broad implications for the origins of evolutionary novelty. Discussions of eye evolution are relevant at many taxonomic levels, especially within arthropods where compound eye distribution is perplexing. Either compound eyes were lost numerous times or very similar eyes evolved separately in multiple lineages. Arthropod compound eye homology

TODD H. OAKLEY

2003-01-01

447

Compound prism design principles, I  

PubMed Central

Prisms have been needlessly neglected as components used in modern optical design. In optical throughput, stray light, flexibility, and in their ability to be used in direct-view geometry, they excel over gratings. Here we show that even their well-known weak dispersion relative to gratings has been overrated by designing doublet and double Amici direct-vision compound prisms that have 14° and 23° of dispersion across the visible spectrum, equivalent to 800 and 1300 lines/mm gratings. By taking advantage of the multiple degrees of freedom available in a compound prism design, we also show prisms whose angular dispersion shows improved linearity in wavelength. In order to achieve these designs, we exploit the well-behaved nature of prism design space to write customized algorithms that optimize directly in the nonlinear design space. Using these algorithms, we showcase a number of prism designs that illustrate a performance and flexibility that goes beyond what has often been considered possible with prisms.

Hagen, Nathan; Tkaczyk, Tomasz S.

2011-01-01

448

Arsenic compounds as anticancer agents.  

PubMed

In this paper the use of arsenic compounds as anticancer agents in clinical trials and in in vitro investigations is reviewed, including the experience at our institute. Treatment of newly diagnosed and relapsed patients with acute promyelocytic leukemia (APL) with arsenic trioxide (As2O3) has been found to result in complete remission (CR) rates of 85-93% when given by intravenous infusion for 2-3 h at a dose of 10 mg/day diluted in 5% glucose saline solution. Patients exhibit a response in 28-42 days. CR rates after administration of Composite Indigo Naturalis tablets containing arsenic sulfide and of pure tetraarsenic tetrasulfide reached 98% and 84.9%, respectively. At higher concentrations (1-2 microM), arsenic induced apoptosis, while at lower concentrations (0.1-0.5 microM), it triggered cell differentiation in vitro. As2O3-induced apoptosis has been observed in many cancer cell lines, including esophageal carcinoma, gastric cancer, neuroblastoma, lymphoid malignancies, and multiple myeloma. Its effectiveness was confirmed in the treatment of multiple myeloma. Arsenic compounds are effective agents in the treatment of APL and their activity against other types of cancer requires further investigation. PMID:11587371

Wang, Z Y

2001-08-01