WorldWideScience

Sample records for excess molar enthalpies

  1. Molecular simulation of excess isotherm and excess enthalpy change in gas-phase adsorption.

    Science.gov (United States)

    Do, D D; Do, H D; Nicholson, D

    2009-01-29

    We present a new approach to calculating excess isotherm and differential enthalpy of adsorption on surfaces or in confined spaces by the Monte Carlo molecular simulation method. The approach is very general and, most importantly, is unambiguous in its application to any configuration of solid structure (crystalline, graphite layer or disordered porous glass), to any type of fluid (simple or complex molecule), and to any operating conditions (subcritical or supercritical). The behavior of the adsorbed phase is studied using the partial molar energy of the simulation box. However, to characterize adsorption for comparison with experimental data, the isotherm is best described by the excess amount, and the enthalpy of adsorption is defined as the change in the total enthalpy of the simulation box with the change in the excess amount, keeping the total number (gas + adsorbed phases) constant. The excess quantities (capacity and energy) require a choice of a reference gaseous phase, which is defined as the adsorptive gas phase occupying the accessible volume and having a density equal to the bulk gas density. The accessible volume is defined as the mean volume space accessible to the center of mass of the adsorbate under consideration. With this choice, the excess isotherm passes through a maximum but always remains positive. This is in stark contrast to the literature where helium void volume is used (which is always greater than the accessible volume) and the resulting excess can be negative. Our definition of enthalpy change is equivalent to the difference between the partial molar enthalpy of the gas phase and the partial molar enthalpy of the adsorbed phase. There is no need to assume ideal gas or negligible molar volume of the adsorbed phase as is traditionally done in the literature. We illustrate this new approach with adsorption of argon, nitrogen, and carbon dioxide under subcritical and supercritical conditions.

  2. Excess enthalpy, density, and heat capacity for binary systems of alkylimidazolium-based ionic liquids + water

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Miaja, Gonzalo; Troncoso, Jacobo [Departamento de Fisica Aplicada, Universidad de Vigo, Facultad de Ciencias, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis [Departamento de Fisica Aplicada, Universidad de Vigo, Facultad de Ciencias, Campus As Lagoas, 32004 Ourense (Spain)], E-mail: romani@uvigo.es

    2009-02-15

    Experimental measurements of excess molar enthalpy, density, and isobaric molar heat capacity are presented for a set of binary systems ionic liquid + water as a function of temperature at atmospheric pressure. The studied ionic liquids are 1-butyl-3-methylpyridinium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-3-methylimidazolium methylsulfate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate. Excess molar enthalpy was measured at 303.15 K whereas density and heat capacity were determined within the temperature range (293.15 to 318.15) K. From experimental data, excess molar volume and excess molar isobaric heat capacity were calculated. The analysis of the excess properties reveals important differences between the studied ionic liquids which can be ascribed to their capability to form hydrogen bonds with water molecules.

  3. Partial molar enthalpies and reaction enthalpies from equilibrium molecular dynamics simulation

    NARCIS (Netherlands)

    Schnell, S.K.; Skorpa, R.; Bedeaux, D.; Kjelstrup, S.H.; Vlugt, T.J.H.; Simon, J.M.

    2014-01-01

    We present a new molecular simulation technique for determining partial molar enthalpies in mixtures of gases and liquids from single simulations, without relying on particle insertions, deletions, or identity changes. The method can also be applied to systems with chemical reactions. We demonstrate

  4. Excess Molar Volumes and Partial Molar Volumes of Binary Systems ...

    African Journals Online (AJOL)

    NJD

    Excess molar volumes have been evaluated from density measurements over the entire composition range for binary systems of an ionic liquid ... was used to fit the excess molar volume data and the partial molar volumes were determined from the Redlich-Kister coefficients. ... ture below the boiling point of water. Most of ...

  5. Standard molar enthalpies of formation of hydroxy-, chlor-, and bromapatite

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Fernando J.A.L. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico 1049-001 Lisbon (Portugal); Minas da Piedade, Manuel E. [Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade de Lisboa, 1749-016 Lisbon (Portugal); Calado, Jorge C.G. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico 1049-001 Lisbon (Portugal)]. E-mail: jcalado@ist.utl.pt

    2005-10-15

    The standard (p{sup 0} =0.1MPa) molar enthalpies of formation in the crystalline state of hydroxyapatite, chlorapatite and a preliminary value for bromapatite, at T=298.15K, were determined by reaction-solution calorimetry as: {delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2},cr]=-(13399+/-11)kJ.mol{sup -1},{delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}Cl{sub 2},cr]=-(13231+/-82)kJ.mol{sup -1},and{delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}Br{sub 2},cr]=-(13063+/-81)kJ.mol{sup -1}. A critical assessment of these results and of previously published data is made. Finally, the standard molar enthalpy of formation of iodapatite is estimated as {delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}I{sub 2},cr]=-12949kJ.mol{sup -1}, from a linear correlation of {delta}{sub f}H{sub m}{sup 0} [Ca{sub 10}(PO{sub 4}){sub 6}X{sub 2},cr] (X=OH, F, Cl, Br) against the corresponding {delta}{sub f}H{sub m}{sup 0} [CaX{sub 2},cr].

  6. Excess Molar Volumes and Partial Molar Volumes of Binary Systems ...

    African Journals Online (AJOL)

    Excess molar volumes have been evaluated from density measurements over the entire composition range for binary systems of an ionic liquid (IL) and an alcohol at T = (298.15, 303.15 and 313.15) K. The IL is 1-butyl-3-methylimidazolium methylsulphate [BMIM]+[MeSO4]– and the alcohols are methanol, ethanol or ...

  7. Excess enthalpy, density, and speed of sound determination for the ternary mixture (methyl tert-butyl ether + 1-butanol + n-hexane)

    Energy Technology Data Exchange (ETDEWEB)

    Mascato, Eva [Departamento de Fisica Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo (Spain); Mariano, Alejandra [Laboratorio de Fisicoquimica, Departamento de Quimica, Facultad de Ingenieria, Universidad Nacional del Comahue, 8300 Neuquen (Argentina); Pineiro, Manuel M. [Departamento de Fisica Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo (Spain)], E-mail: mmpineiro@uvigo.es; Legido, Jose Luis [Departamento de Fisica Aplicada, Facultade de Ciencias, Universidade de Vigo, E-36310 Vigo (Spain); Paz Andrade, M.I. [Departamento de Fisica Aplicada, Facultade de Fisica, Universidade de Santiago de Compostela, E-15706 Santiago de Compostela (Spain)

    2007-09-15

    Density, ({rho}), and speed of sound, (u), from T = 288.15 to T = 308.15 K, and excess molar enthalpies, (h{sup E}) at T = 298.15 K, have been measured over the entire composition range for (methyl tert-butyl ether + 1-butanol + n-hexane). In addition, excess molar volumes, V{sup E}, and excess isentropic compressibility, {kappa}{sub s}{sup E}, were calculated from experimental data. Finally, experimental excess enthalpies results are compared with the estimations obtained by applying the group-contribution models of UNIFAC (in the versions of Dang and Tassios, Larsen et al., Gmehling et al.), and DISQUAC.

  8. Standard molar enthalpies of formation of 2-, 3- and 4-cyanobenzoic acids

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro da Silva, Manuel A.V. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)], E-mail: risilva@fc.up.pt; Amaral, Luisa M.P.F.; Boaventura, Cristina R.P.; Gomes, Jose R.B. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

    2008-08-15

    The standard (p{sup 0} = 0.1 MPa) molar enthalpies of formation of 2-, 3- and 4-cyanobenzoic acids were derived from their standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpies of sublimation of 2- and 3-cyanobenzoic acids. The standard molar enthalpies of formation of the three compounds, in the gaseous phase, at T = 298.15 K, have been derived from the corresponding standard molar enthalpies of formation in the condensed phase and standard molar enthalpies for phase transition. The results obtained are -(150.7 {+-} 2.0) kJ . mol{sup -1}, -(153.6 {+-} 1.7) kJ . mol{sup -1} and -(157.1 {+-} 1.4) kJ . mol{sup -1} for 2-cyano, 3-cyano and 4-cyanobenzoic acids, respectively. Standard molar enthalpies of formation were also estimated by employing two different methodologies: one based on the Cox scheme and the other one based on several different computational approaches. The calculated values show a good agreement with the experimental values obtained in this work.

  9. Excess molar volumes, and refractive index of binary mixtures of ...

    African Journals Online (AJOL)

    Excess molar volumes (VE) viscosities and refractive index have been evaluated for binary mixtures of glycerol + water, and glycerol + methanol at 298.15 K and 303.15 K. Excess molar volumes (VE) have been calculated from density. The excess molar volume (VE) results were fitted to the Redlich and Kister type ...

  10. Excess enthalpies of binary mixtures of 1-hexene with some branched alkanes at the temperature 298.15 K[Excess enthalpy; Binary mixture; 1-Hexene; Branched alkanes; Liebermann-Fried model

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhaohui; Benson, George C.; Lu, Benjamin C.-Y. E-mail: lu@eng.uottawa.ca

    2004-01-01

    Measurements of excess molar enthalpies at the temperature 298.15 K in a flow microcalorimeter are reported for the five binary mixtures formed by mixing 1-hexene with the branched alkanes: 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, 2,3-dimethylbutane, and 2,2,4-trimethylpentane. Smooth Redlich-Kister representations of the results are described. It was found that the Liebermann-Fried model also provided good representations of the results.

  11. Excess molar properties for binary systems of alkylimidazolium-based ionic liquids + nitromethane. Experimental results and ERAS-model calculations

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Miaja, Gonzalo; Troncoso, Jacobo [Departamento de Fisica Aplicada, Universidad de Vigo, Facultad de Ciencias, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis [Departamento de Fisica Aplicada, Universidad de Vigo, Facultad de Ciencias, Campus As Lagoas, 32004 Ourense (Spain)], E-mail: romani@uvigo.es

    2009-03-15

    Density, isobaric molar heat capacity, and excess molar enthalpy were experimentally determined at atmospheric pressure for a set of binary systems ionic liquid + nitromethane. The studied ionic liquids were: 1-butyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-3-methylimidazolium methylsulfate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, and 1-butyl-3-methylimidazolium trifluoromethanesulfonate. Density and heat capacity were obtained within the temperature range (293.15 to 318.15) K whereas excess molar enthalpy was measured at 303.15 K; excess molar volume and excess molar isobaric heat capacity were calculated from experimental data. The ERAS-model was applied in order to study the microscopic mechanisms involved in the mixing process. Although the studied compounds are not self-associated, ERAS-model describe adequately the experimental results if cross-association between both compounds is considered.

  12. Measurements and analysis of excess enthalpies of ester + n-alkane using the UNIFAC model

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, J. (Escuela Superior de Ingenieros Industriales, Las Palmas (Spain). Catedra de Termodinamica y Fisicoquimica); Legido, J.L.; Fernandez, J.; Pias, L.; Paz Andrade, M.I. (Universidad de Santiago de Compostela (Spain). Dept. de Fisica Aplicada)

    1991-02-01

    We present new experimental data of the excess molar enthalpies at 298.15 K for eighteen different binary mixtures of nine methyl alkanoates (ethanoate to decanoate) with n-heptane and n-undecane. The results show that all the systems are endothermic, h{sup E} values increase with the length of the n-alkane and decrease with the length of the methyl ester. The data have been analysed with a version of the UNIFAC model, and the parameters corresponding to the CH{sub 2}/COOC interaction have been recalculated using a larger base of experimental data. New values for the CH{sub 2}/COO interaction parameters have been obtained. (orig.).

  13. excess molar volumes, and refractive index of binary mixtures of ...

    African Journals Online (AJOL)

    Preferred Customer

    mixtures of glycerol + water, and glycerol + methanol at 298.15 K and 303.15 K. Excess molar volumes (VE) have been calculated ... KEY WORDS: Excess molar, Density, Refractive index, Glycerol, Water, Methanol ... Biodiesel, defined as “a substitute for, or a additive to diesel fuel that is derived from the oils and fats of ...

  14. Excess molar volumes and isentropic compressibilities of binary ...

    Indian Academy of Sciences (India)

    Remaining five binary mixtures, n-heptane + toluene, cyclohexane + n-heptane, cyclohexane + n-hexane, toluene + nhexane and n-decane + n-hexane show negative excess molar volumes over the whole composition range. However, the large negative values of excess molar volume becomes dominant in toluene + ...

  15. Excess Molar Volume of Binary Systems Containing Mesitylene

    Directory of Open Access Journals (Sweden)

    Morávková, L.

    2013-05-01

    Full Text Available This paper presents a review of density measurements for binary systems containing 1,3,5-trimethylbenzene (mesitylene with a variety of organic compounds at atmospheric pressure. Literature data of the binary systems were divided into nine basic groups by the type of contained organic compound with mesitylene. The excess molar volumes calculated from the experimental density values have been compared with literature data. Densities were measured by a few experimental methods, namely using a pycnometer, a dilatometer or a commercial apparatus. The overview of the experimental data and shape of the excess molar volume curve versus mole fraction is presented in this paper. The excess molar volumes were correlated by Redlich–Kister equation. The standard deviations for fitting of excess molar volume versus mole fraction are compared. Found literature data cover a huge temperature range from (288.15 to 343.15 K.

  16. Excess Enthalpies of Mixing of Binary Mixtures of NaCl, KCl, NaBr ...

    African Journals Online (AJOL)

    NJD

    2004-07-01

    Jul 1, 2004 ... Excess enthalpies of mixing for six possible binary combinations of solutions of NaCl, KCl, NaBr and KBr in mixed ternary solvents composed of ... practical interest for industrial and geochemical applications. Interest in ... Pitzer,11–16 where the excess Gibbs energy of the system is repre- sented by a ...

  17. Densities and Excess Molar Volume for the Ternary Systems (1 ...

    African Journals Online (AJOL)

    methylimidazolium methyl sulphate ([BMIM]+[MeSO4]-) were determined. The ternary systems studied were ([BMIM]+[MeSO4]-+ nitromethane + methanol or ethanol or 1-propanol) at the temperatures (303.15 and 313.15) K. The ternary excess molar ...

  18. Excess molar volumes and isentropic compressibilities of binary ...

    Indian Academy of Sciences (India)

    However, the large negative values of excess molar volume becomes dominant in toluene. · n-hexane mixture. Deviation in isentropic compressibility is negative over the whole range of composition in the case of all the six binary mixtures. Existence of specific intermolecular interac- tions in the mixtures has been analyzed ...

  19. Excess Molar Volume Of Binarymixtures From Iso-Propyl Alcohol ...

    African Journals Online (AJOL)

    In this work, binary mixtures from Tertiary-Butyl alcohol (TBA), Toluene (TOL) and Iso-Propyl alcohol (IPA) were prepared at 298K. The mixtures physical properties which includes densities of mixtures (ρ) and pure components (ρI) and mole fractions of components (x) were equally measured at 298K. Excess molar volumes ...

  20. excess molar volumes, and refractive index of binary mixtures of ...

    African Journals Online (AJOL)

    Preferred Customer

    product of biodiesel and used in many wide industrial applications. Glycerol can be obtained by ... binary mixtures of glycerol + water and glycerol + methanol covering the whole composition range and at 298.15 K .... 114 the mixture. Excess molar volumes on mixing of the binary systems were fitted to Redlich–. Kister [12 ...

  1. Determinations of enthalpy and partial molar enthalpy in the alloys Bi–Cd–Ga–In–Zn, Bi–Cd–Ga–Zn and Au–Cu–Sn

    Energy Technology Data Exchange (ETDEWEB)

    Arslan, Hüseyin, E-mail: hseyin_arslan@yahoo.com

    2015-03-01

    In the present study, the relations of thermodynamic associated with Chou's general solution model (GSM), the models of Muggianu and Toop have been used in order to calculate the mixing enthalpy and partial molar mixing enthalpy of mixing of Bi–Cd–Ga–In–Zn, Bi–Cd–Ga–Zn with equimolar section at a temperature of 730 K and Au–Cu–Sn with the section x{sub Au}/x{sub Cu} = 1/1 on the entire molar fraction range as a function of alloy composition at a temperature of 900 K. Some negativities are reported in the selected alloys mentioned above, particularly at high temperatures for the human health as well as difficulties in experimental measurement and high costs. Moreover, aim of us is to close the current article gap seen in the literature. In order to close the current gap seen in the literature, the article on the thermodynamic properties of the Bi–Cd–Ga–In–Zn alloys are presented in this study. - Highlights: • Thermodynamic properties of alloys in the study in given conditions were treated. • The activity of Bi seen in all models shows greatly positive deviation from ideality. • The enthalpy of Sn shows small negative values in x{sub Au}/x{sub Cu} = 1 at 900 K. • The activity of Sn shows negative deviation from ideality in the same conditions.

  2. Standard molar Gibbs free energy and enthalpy of solvation of low polar solutes in formamide derivatives at 298 K

    Energy Technology Data Exchange (ETDEWEB)

    Sedov, I.A., E-mail: igor_sedov@inbox.ru; Magsumov, T.I.; Stolov, M.A.; Solomonov, B.N.

    2016-01-10

    Highlights: • Standard molar enthalpies of solution of low polar solutes in NMF were measured. • Limiting activity coefficients in NMF were measured. • The solvophobic effects are present but weaker in NMF than in formamide. • We can tune the solvophobic effects by mixing NMF or formamide with other solvents. - Abstract: Novel experimental values of the limiting activity coefficients and standard molar enthalpies of solution in N-methylformamide at 298.15 K are reported and used to calculate the thermodynamic functions of solvation. We compare the plots of the standard molar Gibbs free energy against the standard molar enthalpy of solvation of low polar molecules in N-methylformamide, N,N-dimethylformamide, and formamide. The solvophobic effect is responsible for the deviations of the data points from the straight line corresponding to a correlation between thermodynamic functions of solvation in aprotic solvents. It is shown that the solvophobic effects are strong in formamide solutions, significantly weaker in N-methylformamide, and very weak in N,N-dimethylformamide, which coincides with the average number of intermolecular hydrogen bonds per unit volume of these solvents. Behavior of solutions in binary solvents composed of N-methylformamide or formamide mixed with water and ethylene glycol and a possibility to tune the solvophobic effect by changing the solvent composition are also considered.

  3. Excess enthalpies of the ternary mixtures: {l_brace}tetrahydrofuran + 3-methylpentane + (octane or decane){r_brace} at the temperature 298.15 K[Excess enthalpy; Ternary mixture; Tetrahydrofuran; 3-Methylpentane; n-Octane; n-Decane; Liebermann-Fried model

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhaohui; Benson, George C. E-mail: gbenson@eng.uottawa.ca; Lu, Benjamin C.-Y

    2003-10-01

    Measurements of excess molar enthalpies at the temperature 298.15 K in a flow microcalorimeter, are reported for the two ternary mixtures {l_brace}X{sub 1}C{sub 4}H{sub 8}O + X{sub 2}CH{sub 3}CH{sub 2}CH(CH{sub 3})CH{sub 2}CH{sub 3} + (1-X{sub 1}-X{sub 2})CH{sub 3}(CH{sub 2}){sub v-2}CH{sub 3}{r_brace} with v=8 and 10. Smooth representations of the results are described and used to construct constant-enthalpy contours on Roozeboom diagrams. It is shown that useful estimates of the ternary enthalpies can be obtained from the Liebermann-Fried model, using only the physical properties of the components and their binary mixtures.

  4. Thermodynamics of biofuels: Excess enthalpies for binary mixtures involving ethyl 1,1-dimethylethyl ether and hydrocarbons at different temperatures using a new flow calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, Jose J. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, E.T.S. de Ingenieros Industriales, Paseo del Cauce s/n 47011, Valladolid (Spain)], E-mail: josseg@eis.uva.es; Carmen Martin, M. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, E.T.S. de Ingenieros Industriales, Paseo del Cauce s/n 47011, Valladolid (Spain)], E-mail: mcmg@eis.uva.es; Vega-Maza, David [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, E.T.S. de Ingenieros Industriales, Paseo del Cauce s/n 47011, Valladolid (Spain)], E-mail: davveg@eis.uva.es; Chamorro, Cesar R. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, E.T.S. de Ingenieros Industriales, Paseo del Cauce s/n 47011, Valladolid (Spain)], E-mail: cescha@eis.uva.es; Villamanan, Miguel A. [Research Group TERMOCAL-Thermodynamics and Calibration University of Valladolid, E.T.S. de Ingenieros Industriales, Paseo del Cauce s/n 47011, Valladolid (Spain)], E-mail: miguel.villamanan@eis.uva.es

    2009-06-15

    Excess molar enthalpies for the binary systems: (ethyl 1,1-dimethylethyl ether + heptane); (ethyl 1,1-dimethylethyl ether + cyclohexane); (ethyl 1,1-dimethylethyl ether + toluene); (cyclohexane + toluene), and (toluene + heptane) have been measured at T = (298.15 and 313.15) K using a new isothermal flow calorimeter developed in the laboratory. The technique was previously checked by measuring test systems. The experimental results have been correlated with the Redlich-Kister polynomial equation. The mixing effects observed and the influence of the temperature are discussed.

  5. Excess enthalpies of binary and ternary mixtures containing dibutyl ether (DBE), 1-butanol, and heptane at T = 298.15 K and 313.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, Fernando; Alaoui, Fatima E.M. [Departamento de Ingenieria Electromecanica, Escuela Politecnica Superior, Universidad de Burgos, E-09006 Burgos (Spain); Segovia, Jose J.; Villamanan, Miguel A. [Grupo de Termodinamica y Calibracion TERMOCAL, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Montero, Eduardo A., E-mail: emontero@ubu.e [Departamento de Ingenieria Electromecanica, Escuela Politecnica Superior, Universidad de Burgos, E-09006 Burgos (Spain)

    2010-01-15

    Experimental excess molar enthalpies of the ternary systems left bracedibutyl ether (DBE) + 1-butanol + heptaneright brace and the corresponding binary systems at T = 298.15 K and T = 313.15 K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and the ternary systems show endothermic character. The experimental data for the binary and ternary systems have been fitted using the Redlich-Kister equation, the NRTL and UNIQUAC models. The values of the standard deviation indicate good agreement between the experimental results and those calculated from the equations.

  6. Properties of mixed-crystalline organic material prepared by zone levelling IV. Melting properties and excess enthalpies of (trans-azobenzene + trans-stilbene)

    NARCIS (Netherlands)

    Bouwstra, J.A.; Leeuw, V.V. de; Miltenburg, J.C.

    1985-01-01

    Homogeneous mixed crystals of (trans-azobenzene + trans-stilbene) were prepared. Molar heat capacities of the pure substances and the mixed crystals were determined at temperatures from 300 to 400 K. The melting temperatures and molar enthalpies of fusion were measured for trans-stilbene and

  7. The CPA Equation of State and an Activity Coefficient Model for Accurate Molar Enthalpy Calculations of Mixtures with Carbon Dioxide and Water/Brine

    Energy Technology Data Exchange (ETDEWEB)

    Myint, P. C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hao, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Firoozabadi, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-03-27

    Thermodynamic property calculations of mixtures containing carbon dioxide (CO2) and water, including brines, are essential in theoretical models of many natural and industrial processes. The properties of greatest practical interest are density, solubility, and enthalpy. Many models for density and solubility calculations have been presented in the literature, but there exists only one study, by Spycher and Pruess, that has compared theoretical molar enthalpy predictions with experimental data [1]. In this report, we recommend two different models for enthalpy calculations: the CPA equation of state by Li and Firoozabadi [2], and the CO2 activity coefficient model by Duan and Sun [3]. We show that the CPA equation of state, which has been demonstrated to provide good agreement with density and solubility data, also accurately calculates molar enthalpies of pure CO2, pure water, and both CO2-rich and aqueous (H2O-rich) mixtures of the two species. It is applicable to a wider range of conditions than the Spycher and Pruess model. In aqueous sodium chloride (NaCl) mixtures, we show that Duan and Sun’s model yields accurate results for the partial molar enthalpy of CO2. It can be combined with another model for the brine enthalpy to calculate the molar enthalpy of H2O-CO2-NaCl mixtures. We conclude by explaining how the CPA equation of state may be modified to further improve agreement with experiments. This generalized CPA is the basis of our future work on this topic.

  8. Excess molar volumes and viscosities of binary mixtures of some ...

    Indian Academy of Sciences (India)

    Unknown

    TvT. (10). In the present study the value of the reduced volume for the liquids and their mixtures ν~ was determined from α values of the mixtures using the (6). Table 5 shows the data4,14,36–38 used in the application of the. Flory model. The excess function (∂Vm. E /∂T)p was computed by analytical differentiation of (3) at ...

  9. Excess enthalpies of mixing, effect of temperature and composition on the density, and viscosity and thermodynamic properties of binary systems of {ammonium-based ionic liquid + alkanediol}.

    Science.gov (United States)

    Domańska, Urszula; Papis, Paulina; Szydłowski, Jerzy; Królikowska, Marta; Królikowski, Marek

    2014-11-06

    In the present work the excess enthalpies of butyltrimethylammonium bis(trifluoromethyl-sulfonyl)imide, [N1114][NTf2], with 1,2-propanediol, or 1,2-butanediol, or 2,3-butanediol have been measured at T = 298.15 K. Additionally, the density, ρ, and dynamic viscosity, η, for binary solutions containing ionic liquids (ILs) and alkanedioles, {butyltrimethylammonium bis(trifluoromethyl-sulfonyl)imide, [N1114][NTf2], + 1,2-propanediol, 1,2-butanediol, 2,3-butanediol} and {(2-hydroxyethyl)trimethylammonium bis(trifluoro-methylsulfonyl)imide, [N1112OH][NTf2], + 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol}, at wide temperature and composition ranges at ambient pressure have been investigated. From experimental values of the density, ρ, and dynamic viscosity, η, the excess molar volumes, V(E), and dynamic viscosity deviations, Δη, were calculated and correlated using the Redlich-Kister polynomial equation. The temperature dependence of density and viscosity for the tested binary systems was described by an empirical second-order polynomial and by the Vogel-Fucher-Tammann equation, respectively. The variation of density and viscosity as a function of composition has been described by the polynomial correlations. Comparison of the experimental results for the binary mixtures tested in this work allows us to determine the influence of alkanediol carbon chain length, the position of the hydroxyl group in the alcohol, and the influence of the structure of the cation of the ionic liquid on the presented properties.

  10. Excess molar volumes of the binary mixtures of polyethylene glycol 300 with ethoxyethanols at various temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kinart, Cezary M. [Department of Chemistry, University of Lodz, 90-236 Lodz, Pomorska 163 (Poland)]. E-mail: ckinart@uni.lodz.pl; Kinart, Wojciech J. [Department of Organic Chemistry, University of Lodz, 90-136 Lodz, Narutowicza 68 (Poland); Cwilinska, Aneta [Department of Chemistry, University of Lodz, 90-236 Lodz, Pomorska 163 (Poland); Klimczak, Magdalena [Department of Chemistry, University of Lodz, 90-236 Lodz, Pomorska 163 (Poland)

    2006-08-15

    Densities at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K in the binary liquid mixtures of polyethylene glycol 300 with 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, or 2-{l_brace}2-(2-ethoxyethoxy)ethoxy{r_brace}ethanol have been measured over the entire range of mixture compositions. These data have been used to compute the excess molar volumes. The excess molar volumes are negative over the entire range of composition for all studied mixtures. The results are discussed in terms of intermolecular interactions in the bulk binary mixtures.

  11. Excess molar volumes and apparent molar volumes of some amide + water systems at 303.15 and 308.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Pal, A.; Singh, Y.P. [Univ. of Kurukshetra (India). Dept. of Chemistry

    1995-07-01

    Excess molar volumes V{sub m}{sup E} for the binary mixtures of N-methylformamide, N,N-dimethylformamide, 2-pyrrolidinone, N-methyl-2-pyrrolidinone, and N,N-dimethylacetamide with water have been measured using a continuous-dilution dilatometer at 303.15 and 308.15 K as a function of composition. In all mixtures, the excess molar volumes are negative over the entire composition range. The results were used to estimate the apparent molar volumes of the components. The values of these two properties have been discussed in terms of intermolecular interactions between the mixing components of the binary mixture.

  12. Excess enthalpies of mixing of piperidinium ionic liquids with short-chain alcohols: measurements and PC-SAFT modeling.

    Science.gov (United States)

    Paduszyński, Kamil; Królikowski, Marek; Domańska, Urszula

    2013-04-11

    This work is a continuation of our systematic study on thermodynamic properties of 1-n-alkyl-1-methylpiperdinium bis[(trifluoromethyl)sulfonyl]imides homologous series of ionic liquids ([CnC1Pip][NTf2]). Excess enthalpies of mixing (H(E)) of four binary systems containing two ionic liquids, namely [C4C1Pip][NTf2] and [C6C1Pip][NTf2], and two short-chain alcohols, namely ethanol and 1-propanol, were measured by isothermal titration calorimetry. Alcohol-to-ionic liquid and ionic liquid-to-alcohol titration experiments were carried out at temperature T = 298.15 K and atmospheric pressure. The experimental data were modeled in terms of perturbed-chain statistical associating fluid theory (PC-SAFT). Wolbach-Sandler combining rules were adopted in order to account for ionic liquid-alcohol cross-association. The model was applied in a conventional manner (i.e., without any binary corrections) as well as in a novel predictive mode developed previously by our group [Paduszyński, K.; Domańska, U. J. Phys. Chem. B 2012, 116, 5002-5018; Domańska et al. J. Phys. Chem. B 2012, 116, 8191-8200]. The latter approach employs temperature-dependent binary correction fitted to experimental limiting activity coefficient of alcohol in ionic liquid.

  13. Vapor-liquid equilibria and excess enthalpies for octane + N-methylacetamide, cyclooctane + N-methylacetamide, and octane + acetic acid anhydride at 125 C

    Energy Technology Data Exchange (ETDEWEB)

    Haan, A.B. de [DSM-Research, Geleen (Netherlands); Heine, A.; Fischer, K.; Gmehling, J. [Univ. Oldenburg (Germany)

    1995-11-01

    Isothermal P-x data and excess enthalpies have been measured at approximately 125 C for the binary mixtures of octane + N-methylacetamide, cyclooctane + N-methylacetamide, and octane + acetic anhydride. For each binary system linear temperature dependent interaction parameters were fitted to experimental data using the NRTL model. Activity coefficients at infinite dilution were derived from the P-x data at low concentrations using a flexible Legendre polynomial.

  14. Solvation molar enthalpies and heat capacities of n-alkanes and n-alkylbenzenes on stationary phases of wide-ranging polarity.

    Science.gov (United States)

    Lebrón-Aguilar, Rosa; Quintanilla-López, Jesús Eduardo; Santiuste, José María

    2010-12-03

    A comparison of the most usual gas chromatographic methods for the calculation of partial molar enthalpies of solvation (Δ(sol)H(o)) has been carried out. Those methods based on the fitting of lnV(g) or ln(k/T) vs. 1/T and ln(k/T) vs. (1/T and the temperature arrangement, T(a)) are the most adequate ones for obtaining Δ(sol)H(o) values. However, the latter is the only reliable option for Δ(sol)H(o) estimation when commercial WCOT capillary columns are used, since in this case the estimation of some variables involved in the V(g) determination is less accurate or even impossible. Consequently, in this paper, Δ(sol)H(o) obtained from ln(k/T) vs. (1/T+T(a)) fitting at 373.15 and 298.15K for n-alkanes and n-alkylbenzenes on 12 commercial capillary columns coated with stationary phases covering the 203-3608 McReynolds polarity range are reported. Moreover, molar heat capacities of solvation at constant pressure (Δ(sol)C(p)(o)) have also been calculated using this method. A clear influence on Δ(sol)H(o) of the type and content of the substitution group in the stationary phase was observed. In addition, a linear relationship of Δ(sol)C(p)(o) with the van der Waals volume of the n-alkanes and the temperature gradient of density of the stationary phase was found. The effect of the size of the hydrocarbon on both thermodynamic variables was also investigated. Copyright © 2010 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2014-07-01

    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.

  16. Low temperature heat capacities and standard molar enthalpy of formation of sodium benzoate C{sub 6}H{sub 5}COONa (s)

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Yu-Xia [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Di, You-Ying, E-mail: yydi@lcu.edu.cn [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Qi, Yu-Dong; Yang, Wei-Wei [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Tan, Zhi-Cheng [Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2009-05-05

    Sodium benzoate was synthesized by the method of liquid phase synthesis, in which benzoic acid and anhydrous sodium carbonate were chosen as the reactants. The structure and composition of the compound were characterized by FTIR, chemical analysis, elemental analysis and X-ray powder diffraction techniques. Low temperature heat capacities of the compound were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of the heat capacities as a function of the temperature was fitted by least square method. The smoothed heat capacities and the thermodynamic functions of the compound relative to 298.15 K have been calculated based on the equation. In accordance with Hess law, the standard molar enthalpy of formation of the title compound C{sub 6}H{sub 5}COONa (s) was determined to be {Delta}{sub f}H{sup o}{sub m}[C{sub 6}H{sub 5}COONa,s]=-(642.56{+-}0.64)kJmol{sup -1} by using an isoperibol solution-reaction calorimeter.

  17. Topological Investigations of Excess Molar Volumes and Excess Isentropic Compressibilities of Ternary Mixtures Containing Pyrrolidin-2-one at 308.15 K

    Science.gov (United States)

    Yadav, Jaibir S.; Sharma, Dimple; Kumar, Satish; Sharma, V. K.

    2010-12-01

    Excess molar volumes, {V^E_{ijk}}, and speeds of sound, u ijk , of pyrrolidin-2-one (2-Py) ( i)+benzene or methyl benzene ( j)+propan-1-ol ( k) ternary mixtures and speeds of sound, u ij , of benzene or methyl benzene ( i)+propan-1-ol ( j) binary mixtures have been measured dilatometrically and interferrometrically over the complete mole fraction range at 308.15 K. Speed-of-sound data have been utilized to evaluate excess isentropic compressibilities for binary and ternary mixtures. {V^E_{ijk}} and {({kappa_S^E})_{ijk}} values have been fitted to a Redlich-Kister equation to predict ternary adjustable parameters and standard deviations. Topological investigations employed for predicting excess molar volumes and excess isentropic compressibilities, {({kappa _S^E} )_{ij}}, of 2-Py + benzene or methyl benzene or propan-1-ol binary mixtures have been extended to ternary mixtures (by employing the concept of a connectivity parameter of third degree, 3 ξ, of a molecule) to obtain an expression that describes well the measured {V^E_{ijk}} and {({kappa_S^E})_{ijk}} values.

  18. Excess molar volumes of 1,3 propanediol + (C1-C5 alkan-1-ols: Application of cubic EOS

    Directory of Open Access Journals (Sweden)

    Almasi Mohammad

    2012-01-01

    Full Text Available Densities of the binary mixtures consist of methanol, ethanol, 1- propanol, 1-butanol and 1-pentanol with 1,3 Propanediol were measured at temperatures (293.15, 298.15, 303.15 and 313.15 K and atmospheric pressure. Measurements have been made over the full range of compositions and for the pure compounds by using a vibrating tube densimeter. Excess molar volumes have been obtained from these experimental results and were fitted to a Redlich-Kister type expansion. The results were interpreted in terms of molecular interactions and structural factors of the alcohols. It was observed that an increase of the alcohol carbon chain length led to lower interactions on mixing. The Peng-Robinson-Stryjek-Vera (PRSV equation of state has been used to correlate the binary excess molar volumes.

  19. Excess molar volume of acetonitrile + alcohol systems at 298.15 K. Part II: Correlation by cubic equation of state

    Directory of Open Access Journals (Sweden)

    SLOBODAN P. SERBANOVIC

    2003-01-01

    Full Text Available The excess molar volume VE of the binary liquid systems acetonitrile + methanol and acetonitrile + ethanol, experimentally determined in the previous part, were correlated by the PRSV CEOS coupled with the vdW and TCBT mixing rules. The results obtained show that the number and position of the interaction parameters of these models are of great importance for a satisfactory fitting of VE data.

  20. Enthalpy studies

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, P.M.; Stein, F.P.

    1983-09-01

    This report describes the evaluation and enhancement of the enthalpy model developed for the SRC-I process (as well as other coal liquefaction processes). The enthalpy model has been described in a previous report (Mathias and Monks, 1982). A key feature of the model is the proposed extended corresponding-states framework, obtained through the introduction of a new parameter, termed the polar parameter. It is usual practice to treat the essentially continuous coal-fluid mixture as a set of pseudocomponents, each defined by a narrow range in normal boiling point. The model developed by Mathias and Monks (1982) characterizes each pseudocomponent with the normal boiling point, specific gravity, and polar parameter. Mathias and Monks found that the model provided an excellent description of existing coal-fluid enthalpy data - if the polar parameter was chosen to best fit the data. However, use of the model in process design requires a predictive method for the polar parameter. ICRC is conducting a program to obtain enthalpy measurements in order to provide verification of the current design conditions for the SRC-I Demonstration Plant and data for developing reliable correlations (Mehta, et al., 1983). A majority of the data has been received, analysis of which is described in this report. Comparison of the model to data on three SRC-I 50/sup 0/F boiling fractions indicates, again, that the data is well correlated if the optimum value of the polar parameter is used. More importantly, this analysis has provided a reasonable basis to predict the values of the polar parameters for all the pseudocomponents employed in the simulation of the SRC-I process. The proposed model has provided encouraging agreement with experimental data, but final conclusions must await analysis of the entire set of data.

  1. Nuclear enthalpies

    Directory of Open Access Journals (Sweden)

    Rozynek Jacek

    2015-01-01

    Full Text Available Even small departures from a nuclear equilibrium density with constant nucleon masses require an increase of a nucleon enthalpy. This process can be described as volume corrections to a nucleon rest energy, which are proportional to pressure and absent in a standard Relativistic Mean Field (RMF with point-like nucleons. Bag model and RMF calculations show the modifications of nucleon mass, nucleon radius and a Parton Distribution Function (PDF of Nuclear Matter (NM above the saturation point originated from the pressure correction.

  2. Excess molar volumes and deviations of the relative permittivity of the binary mixtures of 2-propoxyethanol with diethylene, triethylene, and tetraethylene glycols at various temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Cwilinska, Aneta; Klimczak, Magdalena [Department of Chemistry, University of Lodz, 90-236 Lodz, Pomorska 163 (Poland); Kinart, Wojciech J. [Department of Organic Chemistry, University of Lodz, 90-136 Lodz, Narutowicza 68 (Poland); Kinart, Cezary M. [Department of Chemistry, University of Lodz, 90-236 Lodz, Pomorska 163 (Poland)], E-mail: ckinart@uni.lodz.pl

    2008-03-15

    Densities and relative permittivities at T = (293.15, 298.15, and 303.15) K in the binary liquid mixtures of 2-propoxyethanol with diethylene glycol, triethylene glycol, and tetraethylene glycol have been measured over the entire mixture compositions. These data have been used to compute the excess molar volumes and deviations of the relative permittivity. The results are discussed in terms of intermolecular interactions in the bulk of studied the binary mixtures.

  3. DENSITY, REFRACTIVE INDEX, APPARENT VOLUMES AND EXCESS MOLAR VOLUMES OF FOUR PROTIC IONIC LIQUIDS + WATER AT T=298.15 AND 323.15 K

    Directory of Open Access Journals (Sweden)

    R. Rocha Pinto

    2015-09-01

    Full Text Available AbstractDensities and refractive index of binay mixtures of water with four protic ionic liquids, based on ammonium and fatty acids, were measured at 298.15 and 323.15 K, under atmospheric pressure. Apparent and excess molar volumes were obtained by experiments and fitting data to the Redlich-Meyer (RM, Redlich-Kister (RK and Prigogine-Flory-Patterson (PFP equations. The molar volume values were high, suggesting strong ion-solvent interaction. The same interaction also became stronger as the temperature increased. Excess volume values were negative, indicating that packing efficiency ability or attractive interactions occurred in mixtures of ionic liquid + water. The errors (AARD for the properties in excess were in the range of 1.8% to 7.2%. The PFP error for the apparent volume was in the range of 0.34% to 0.06%, lower than the RM error for the same property, which was in the range of 0.70 to 1.55%. The Gladstone-Dale model was applied to correlate the refractive index of the binary mixture with the density from the values of both pure components.

  4. Excess molar volumes of (an alkanol plus a branched chain ether) at the temperature 298.15 K and the application of the ERAS model

    CSIR Research Space (South Africa)

    Letcher, TM

    1997-12-01

    Full Text Available The excess molar volumes V-m(E) {x(CH3OH or CH3CH2OH or CH3(CH2)(2)OH or CH3CH(OH)CH3 + (1 - x)(CH3(CH2)(2)}(2)O or CH3C(CH3)(2)OCH3 or CH3CH2C(CH3)(2)OCH3} have been calculated from measured values of density over the whole composition range...

  5. Characteristics of combustion and heat transfer of excess enthalpy flames stabilized in a stagnation flow. 2nd Report. ; Heat flux at high flow rate and effects of Lewis number. Yodomi nagarechu ni anteika sareta choka enthalpy kaen no nensho oyobi etsudentatsu tokusei. 2. ; Koryuryo ni okeru netsuryusoku oyobi Lewis su no koka

    Energy Technology Data Exchange (ETDEWEB)

    Ito, S. (Daido Institute of Technology, Nagoya (Japan)); Asato, K.; Kawamura, T. (Gifu University, Gifu (Japan). Faculty of Engineerirng); Mazaki, T. (Daido Senior High School, Nagoya (Japan)); Umemura, H. (Mitsubishi Electric Corp., Tokyo (Japan))

    1993-08-25

    For the purpose of developing small-sized combustors of high heat transfer efficiency for household and business uses, a study has been carried out on the characteristics of an excess enthalpy flame stabilized in a stagnant flow, the maximum heat flux utilizable from flames through a heat receiver wall, the heat transfer characteristics near the extinction limits, and the effects of Lewis number (Le). Even when heat is drawn from the heat receiver wall in the downstream of flames, stable flames are kept until they extremely approach the heat receiver wall by the effect of preheating for lean methane-air flames of Le[approx equal]1.0 and lean propane-air flames of Le>1.0 and by the effect of preheating and Lewis effect for lean hydrogen-air flames of Le<1.0. In any flames, therefore, the heat flux to the heat receiver wall increases abruptly with the increase of stagnant velocity gradient and thereby the heat transfer characteristics at the heat receiver wall are improved. Heat transfer in the cases where flames exist on the outside and inside of the temperature boundary layer depend not on the thickness of the temperature boundary layer but on the position of flames. 6 refs., 9 figs.

  6. Excess properties and vapour pressure of left brace3-diethylaminopropylamine + cyclohexaneright brace

    Energy Technology Data Exchange (ETDEWEB)

    Khimeche, Kamel, E-mail: kamel.khimeche@yahoo.f [Ecole Militaire Polytechnique EMP, BP 17 Bordj-El-Bahri, Alger (Algeria); Dahmani, Abdallah [Laboratoire de thermodynamique et modelisation moleculaire, Faculte de chimie, USTHB, BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria); Mokbel, Ilham [Laboratoire de chimie analytique I, Universite Claude Bernard (Lyon I), 43, bd du 11 Novembre 1918 69622 Villeurbanne (France)

    2010-07-15

    The vapour pressures of liquid left brace3-diethylaminopropylamine (3-DEPA) + cyclohexaneright brace were measured by a static method between T = (273.15 and 363.15) K at 10 K intervals. The excess molar volumes V{sup E} at 298.15 K and excess molar enthalpies H{sup E} at 303.15 K were also measured. The molar excess Gibbs free energies G{sup E} were obtained with Barker's method and fitted to the Redlich-Kister equation. The Wilson equation was also used. Deviations between experimental and predicted G{sup E} and H{sup E}, by using DISQUAC model, were evaluated

  7. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  8. High enthalpy gas dynamics

    CERN Document Server

    Rathakrishnan, Ethirajan

    2014-01-01

    This is an introductory level textbook which explains the elements of high temperature and high-speed gas dynamics. written in a clear and easy to follow style, the author covers all the latest developments in the field including basic thermodynamic principles, compressible flow regimes and waves propagation in one volume covers theoretical modeling of High Enthalpy Flows, with particular focus on problems in internal and external gas-dynamic flows, of interest in the fields of rockets propulsion and hypersonic aerodynamics High enthalpy gas dynamics is a compulsory course for aerospace engine

  9. ACTIVATION PARAMETERS AND EXCESS THERMODYANAMIC ...

    African Journals Online (AJOL)

    Applying these data, viscosity-B-coefficients, activation parameters (Δμ10≠) and (Δμ20≠) and excess thermodynamic functions, viz., excess molar volume (VE), excess viscosity, ηE and excess molar free energy of activation of flow, (GE) were calculated. The value of interaction parameter, d, of Grunberg and Nissan ...

  10. Enthalpy studies. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mathias, P.M.; Stein, F.P.

    1984-05-01

    This report describes the evaluation and enhancement of the enthalpy model developed for the SRC-I process (as well as the other coal-liquefaction processes). A preliminary version of the model was used in the Post-Baseline review of the SRC-I process design (Duffy et al., 1983), and the final version will be employed by APCI in the ASPEN PLUS Model of the SRC-I Demonstration Plant (APCI, 1984). ICRC, recognizing the need for thermophysical data on coal liquids and coal-fluid model compounds, embarked upon a 2-year experimental program. Specifically, the overall program objectives were to obtain vapor/liquid equilibrium (VLE) and enthalpy data to develop correlations and verify the designs of several important pieces of process equipment in the SRC-I demonstration plant. The enthalpy model uses a modification of the Peng-Robinson (1976) equation of state proposed by Mathias ad Copeman (1983). It was developed mainly from publicly available data on coal fluids and related model compounds (Mathias and Monks, 1982). The generalized (predictive) model has provided good agreement with experimental data on coal fluids. Surprisingly, the agreement with the data on model-compound mixtures is not as good. The practical conclusion is that, within the frame work of the present model, it is better to lump various types of components within the same pseudocomponent. The enthalpy model has achieved the main objective of an improved model for the design of several key heat exchangers in the SRC-I process. Further, the work has identified deficiencies in existing models, which suggest the focus of future research. 24 references.

  11. MOLAR UPRIGHTING

    Directory of Open Access Journals (Sweden)

    Eka Erwansyah

    2006-04-01

    Full Text Available The mesial tipping of molar is frequently found in orthodontic cases. This molar malposition must be corrected since it may cause periodontal disorders, occlusal interferences, and temporomandibular joint dysfunction, and is often needed in planning a fixed bridge. This paper is a literature study to discuss about appliance designs, indication, and contraindications, and complication and treatment protocols of molar uprighting by fixed orthodontic appliances. By knowing the techniques of molar uprighting, the moments mentioned above can be avoided.

  12. Excess molar volume, viscosity, and refractive index study for the ternary mixture {l_brace}2-methyl-2-butanol (1) + tetrahydrofuran (2) + propylamine (3){r_brace} at different temperatures. Application of the ERAS-model and Peng-Robinson-Stryjek-Vera equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Fattahi, M. [Faculty of Chemistry, University of Bu-Ali Sina, Hamedan 65174 (Iran, Islamic Republic of); Iloukhani, H., E-mail: iloukhani@basu.ac.i [Faculty of Chemistry, University of Bu-Ali Sina, Hamedan 65174 (Iran, Islamic Republic of)

    2010-11-15

    Densities, viscosities, and refractive indices of the ternary mixture consist of {l_brace}2-methyl-2-butanol (1) + tetrahydrofuran (THF) (2) + propylamine (3){r_brace} at a temperature of 298.15 K and related binary mixtures were measured at temperatures of (288.15, 298.15, and 308.15) K at ambient pressure. Data were used to calculate the excess molar volumes and the deviations of the viscosity and refractive index. The Redlich-Kister and the Cibulka equations were used for correlating binary and ternary properties, respectively. The ERAS-model has been applied for describing the binary and ternary excess molar volumes and also Peng-Robinson-Stryjek-Vera (PRSV) equation of state (EOS) has been used to predict the binary and ternary excess molar volumes and viscosities.

  13. Excess Molar Volumes and Viscosities for the Binary Mixtures of n-Octane, n-Decane, n-Dodecane, and n-Tetradecane with Octan-2-ol at 298.15 K

    Directory of Open Access Journals (Sweden)

    Arvind R. Mahajan

    2013-01-01

    Full Text Available Experimental values of densities (ρ and viscosities (η in the binary mixtures of n-octane, n-decane, n-dodecane, and n-tetradecane with octan-2-ol are presented over the whole range of mixture composition at T=298.15 K. From these data, excess molar volume (VmE, deviations in viscosity (Δη, and excess Gibbs free energy of activation ΔG∗E have been calculated. These results were fitted to Redlich-Kister polynomial equations to estimate the binary coefficients and standard errors. Jouyban-Acree model is used to correlate the experimental values of density and viscosity at T=298.15 K. The values of VmE have been analyzed using Prigogine-Flory-Patterson (PFP theory. The results of the viscosity composition are discussed in the light of various viscosity equations suggested by Grunberg-Nissan, Tamara and Kurata, Hind et al., Katti and Chaudhri, Heric, Heric and Brewer, and McAllister multibody model. The values of Δlnη have also been analyzed using Bloomfield and Dewan model. The experiments on the constituted binaries are analyzed to discuss the nature and strength of intermolecular interactions in these mixtures.

  14. Enthalpy screen of drug candidates.

    Science.gov (United States)

    Schön, Arne; Freire, Ernesto

    2016-11-15

    The enthalpic and entropic contributions to the binding affinity of drug candidates have been acknowledged to be important determinants of the quality of a drug molecule. These quantities, usually summarized in the thermodynamic signature, provide a rapid assessment of the forces that drive the binding of a ligand. Having access to the thermodynamic signature in the early stages of the drug discovery process will provide critical information towards the selection of the best drug candidates for development. In this paper, the Enthalpy Screen technique is presented. The enthalpy screen allows fast and accurate determination of the binding enthalpy for hundreds of ligands. As such, it appears to be ideally suited to aid in the ranking of the hundreds of hits that are usually identified after standard high throughput screening. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Molar Pregnancy

    Science.gov (United States)

    ... Vaginal bleeding Molar pregnancy Symptoms & causes Diagnosis & treatment Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  16. Compressed liquid densities and excess molar volumes for (CO{sub 2} + 1-pentanol) binary system at temperatures from 313 to 363 K and pressures up to 25 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga-Moreno, Abel [Instituto Politecnico Nacional, ESIQIE, Laboratorio de Termodinamica, Edif. Z, Secc. 6, 1er piso, UPALM Zacatenco, 07738, Lindavista, Mexico, D.F. (Mexico); Galicia-Luna, Luis A. [Instituto Politecnico Nacional, ESIQIE, Laboratorio de Termodinamica, Edif. Z, Secc. 6, 1er piso, UPALM Zacatenco, 07738, Lindavista, Mexico, D.F. (Mexico)], E-mail: lgalicial@ipn.mx; Sandler, Stanley I. [Department of Chemical Engineering, University of Delaware, Newark, DE 19716-3119 (United States)

    2008-02-15

    Measurements of compressed liquid densities for 1-pentanol and for {l_brace}CO{sub 2} (1) + 1-pentanol (2){r_brace} system were carried out at temperatures from 313 K to 363 K and pressures up to 25 MPa. Densities were measured for binary mixtures at 10 different compositions, x{sub 1} = 0.0816, 0.1347, 0.3624, 0.4651, 0.6054, 0.7274, 0.8067, 0.8573, 0.9216, and 0.9757. A vibrating tube densimeter was used to perform density measurements using two reference calibration fluids. The uncertainty is estimated to be better than {+-}0.2 kg . m{sup -3} for the experimental density measurements. For each mixture and for 1-pentanol, the experimental densities were correlated using an explicit volume equation of six parameters and an 11-parameter equation of state (EoS). Excess molar volumes were determined for the (CO{sub 2} + 1-pentanol) system using 1-pentanol densities calculated from the 11-parameter EoS and CO{sub 2} densities calculated from a multiparameter reference EoS.

  17. The Correlation of Standard Entropy with Enthalpy Supplied from 0 to 298.15 K

    Science.gov (United States)

    Lambert, Frank L.; Leff, Harvey S.

    2009-01-01

    As a substance is heated at constant pressure from near 0 K to 298 K, each incremental enthalpy increase, dH, alters entropy by dH/T, bringing it from approximately zero to its standard molar entropy S degrees. Using heat capacity data for 32 solids and CODATA results for another 45, we found a roughly linear relationship between S degrees and…

  18. Calculation of partial enthalpies in argon-krypton mixtures by NPT molecular dynamics

    NARCIS (Netherlands)

    Sindzingre, P.; Massobrio, C.; Ciccotti, G.; Frenkel, D.

    1989-01-01

    In an earlier paper, we have indicated how, by using a particle-insertion technique, partial molar enthalpies and related quantities can be evaluated from simulations on a single state point. In the present paper we apply this method to a Lennard-Jones argon-krypton mixture. For this particular

  19. Enthalpies of sublimation of fullerenes by thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Herrera, Melchor; Campos, Myriam; Torres, Luis Alfonso; Rojas, Aarón, E-mail: arojas@cinvestav.mx

    2015-12-20

    Graphical abstract: - Highlights: • Enthalpies of sublimation of fullerenes were measured by thermogravimetry. • Results of enthalpies of sublimation are comparable with data reported in literature. • Not previously reported enthalpy of sublimation of C{sub 78} is supplied in this work. • Enthalpies of sublimation show a strong dependence with the number of carbon atoms in the cluster. • Enthalpies of sublimation are congruent with dispersion forces ruling cohesion of solid fullerene. - Abstract: The enthalpies of sublimation of fullerenes, as measured in the interval of 810–1170 K by thermogravimetry and applying the Langmuir equation, are reported. The detailed experimental procedure and its application to fullerenes C{sub 60}, C{sub 70}, C{sub 76}, C{sub 78} and C{sub 84} are supplied. The accuracy and uncertainty associated with the experimental results of the enthalpy of sublimation of these fullerenes show that the reliability of the measurements is comparable to that of other indirect high-temperature methods. The results also indicate that the enthalpy of sublimation increases proportionally to the number of carbon atoms in the cluster but there is also a strong correlation between the enthalpy of sublimation and the polarizability of each fullerene.

  20. Polymer-Polymer Miscibility and Enthalpy Relaxations

    NARCIS (Netherlands)

    Bosma, Martin; Brinke, Gerrit ten; Ellis, Thomas S.

    Annealing of polymers below the glass transition temperature results in a decrease in enthalpy that is recovered during heating. The enthalpy recovery is visible as an endothermic peak in a differential scanning calorimetry (DSC) scan. The position of this peak depends on the thermal treatment given

  1. Deciduous molar hypomineralization and molar incisor hypomineralization

    NARCIS (Netherlands)

    Elfrink, M.E.C.; ten Cate, J.M.; Jaddoe, V.W.V.; Hofman, A.; Moll, H.A.; Veerkamp, J.S.J.

    2012-01-01

    This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop

  2. Large-scale calculations of gas phase thermochemistry : Enthalpy of formation, standard entropy, and heat capacity

    OpenAIRE

    Ghahremanpour, Mohammad M.; van Maaren, Paul J.; Ditz, Jonas C.; Lindh, Roland; van der Spoel, David

    2016-01-01

    Large scale quantum calculations for molar enthalpy of formation (Delta(f) H-0), standard entropy (S-0), and heat capacity (C-V) are presented. A large data set may help to evaluate quantum thermochemistry tools in order to uncover possible hidden shortcomings and also to find experimental data that might need to be reinvestigated, indeed we list and annotate approximately 200 problematic thermochemistry measurements. Quantum methods systematically underestimate S-0 for flexible molecules in ...

  3. Anomalous enthalpy relaxation in vitreous silica

    DEFF Research Database (Denmark)

    Yue, Yuanzheng

    2015-01-01

    It is a challenge to calorimetrically determine the glass transition temperature (Tg) of vitreous silica. Here, we demonstrate that this challenge mainly arises from the extremely high sensitivity of the Tg to the hydroxyl content, but also from decrease of the Tg with repeating the calorimetric...... scans. It is known that the liquid fragility (i.e., the speed of the viscous slow-down of a supercooled liquid at its Tg during cooling) has impact on enthalpy relaxation in glass. Here, we find that vitreous silica (as a strong system) exhibits striking anomalies in both glass transition and enthalpy...... relaxation compared to fragile oxide systems. The anomalous enthalpy relaxation of vitreous silica is discovered by performing the hyperquenching-annealing-calorimetry experiments. We argue that the strong systems like vitreous silica and vitreous Germania relax in a structurally cooperative manner, whereas...

  4. Excessive somnolence

    Directory of Open Access Journals (Sweden)

    Stella Tavares

    Full Text Available Excessive somnolence can be quite a incapacitating manifestation, and is frequently neglected by physicians and patients. This article reviews the determinant factors, the evaluation and quantification of diurnal somnolence, and the description and treatment of the main causes of excessive somnolence.

  5. Excessive somnolence.

    Science.gov (United States)

    Tavares, S; Alóe, F; Gentil, V; Scaff, M

    1996-01-01

    Excessive somnolence can be quite a incapacitating manifestation, and is frequently neglected by physicians and patients. This article reviews the determinant factors, the evaluation and quantification of diurnal somnolence, and the description and treatment of the main causes of excessive somnolence.

  6. The Optimal Use of Entropy and Enthalpy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 9. The Optimal Use of Entropy and Enthalpy. M S Ananth R Ravi. General Article Volume 6 Issue 9 ... Author Affiliations. M S Ananth1 R Ravi1. Department of Chemical Engineering, Indian Institute of Technology, Chennai 600 036, India.

  7. Second molar germectomy and third molar eruption. 11 cases of lower second molar enucleation.

    Science.gov (United States)

    Gaumond, G

    1985-01-01

    Eleven cases followed from enucleation of the unerupted lower second molars through third molar eruption. While results were generally good, three presented third molar malpositions requiring further treatment.

  8. [Hyperthyroidism in molar pregnancy].

    Science.gov (United States)

    Boufettal, H; Mahdoui, S; Noun, M; Hermas, S; Samouh, N

    2014-03-01

    Hyperthyroidism is a rare complication of molar pregnancy. We report a 39-year-old woman who presented a thyrotoxic syndrome accompanying a molar pregnancy. Serum thyroid hormones were elevated and returned to normal level after uterine evacuation of a molar pregnancy. The authors detail the role of thyroid stimulating property of human gonadotropin chorionic hormone and its structural changes during the gestational trophoblastic diseases. These changes give the latter the thyroid stimulating properties and signs of hyperthyroidism. Molar pregnancy may be a cause of hyperthyroidism. The diagnosis of molar pregnancy should be a mention to thyrotoxicosique syndrome in a woman of childbearing age. Copyright © 2013. Published by Elsevier SAS.

  9. Sextant of Sapphires for Molar Distalization.

    Science.gov (United States)

    Ponnada, Swaroopa Rani; Palla, Yudistar Venkata; Ganugapanta, Vivek Reddy

    2016-08-01

    Space analysis quantifies the amount of crowding within the arches estimating the severity of space discrepancy. The space gaining procedures include extraction and non-extraction procedures like expansion, proximal stripping and molar distalization. To identify features seen in molar distalization cases. The sample size comprised 20 patients in whom molar distalization was decided as the treatment plan. The study models and lateral cephalograms of all the patients were taken. Occlusograms were obtained. Model analysis and cephalometric analysis were performed. Descriptive statistical analysis like mean, standard deviation, standard error and mode were done. The parameters in Question gave following results. The Bolton analysis showed anterior mandibular excess with mean value of 1.56mm±1.07. The first order discrepancy between maxillary central and lateral incisors was 5±1.95. The premolar rotation showed mean value of 16.58±5.12. The molar rotation showed the value of 7.66±2.26. The nasolabial angle showed the mean of 101.25±8.7 IMPA of 101.4±5.74. The six features studied in molar distalization cases [First order discrepancy between upper central and lateral incisors; Rotation of premolars and molars; Bolton's discrepancy in anterior dentition; Average to horizontal growth pattern; Proclined lower incisors and Obtuse nasolabial angle] can be taken as patterns seen in molar distalization cases and considered as a valid treatment plan.

  10. Enthalpy of formation of natural amesite

    Science.gov (United States)

    Ogorodova, L. P.; Mel'chakova, L. V.; Vigasina, M. F.; Ksenofontov, D. A.; Bryzgalov, I. A.

    2015-02-01

    Natural amesite from the Saranovsk deposit of chromites (Perm krai, Russia) and characterized using a number of contemporary physicochemical methods is studied thermochemically on a Setaram high-temperature heat-flux Tian-Calvet microcalorimeter (France). The enthalpy of formation from the simple substances Δf H°(298.15 K) = -4518.3 ± 9.2 kJ/mol for Mg2Al[SiAlO5](OH)4 amesite is determined via melt dissolution calorimetry.

  11. Removable molar power arm

    Directory of Open Access Journals (Sweden)

    Raj Kumar Verma

    2013-01-01

    Full Text Available Attachment of force elements from the gingival hook of maxillary molar tubes during the retraction of the anterior teeth is very common in orthodontic practice. As the line of force passes below the center of resistance (CR of molar, it results its mesial tipping and also anchorage loss. To overcome this problem, the line of force should pass along the CR of molar. This article highlights a method to overcome this problem by attaching a removable power arm to the headgear tube of molar tube during the retraction of the anterior teeth.

  12. Ruptured tubal molar pregnancy

    African Journals Online (AJOL)

    2011-05-19

    May 19, 2011 ... Nigerian Journal of Clinical Practice • Oct-Dec 2012 • Vol 15 • Issue 4. Yakasai, et al.: Tubal molar pregnancy follow-up using serial βhCG measurements similar to other trophoblastic tumors.[6] The outcome of the treatment of these patients is similar to those coming with non-molar ectopic gestation.

  13. Enthalpy Calculation for Pressurized Oxy- coal Combustion

    OpenAIRE

    Weihong Wu; Jingli Huang

    2012-01-01

    Oxy-fuel combustion is recognizing one of the most promising available technologies that zero emission accomplishment may be in the offing. With coal burned under the pressure of 6MPa and oxygen-enriched conditions, the high temperature and high pressure gaseous combustion product is composed of 95% CO2 and water-vapor, with the rest of O2, N2 and so on. However, once lauded as classic approach of resolving fuel gas enthalpy calculation pertaining to ideal gas at atmospheric pressure was rest...

  14. Biomechanics in Molar Control

    OpenAIRE

    Rendón Giraldo, Juan Esteban; Castaño, Gabriel

    2014-01-01

    Inadequate molar control is one of the difficulties that arise during mechanical treatment. When molar control is handled efficiently, it facilitates precise control of forces and moments, which increases the effectiveness of biomechanics. Knowledge of 4 x 2, 6 x 2 partial systems and the transpalatal bar with its different forms of activation offer a number of advantages that make it possible to optimize orthodontic results. The aim of this article is to clarify concepts, specify possible tr...

  15. Densities and Excess Molar Volume for the Ternary Systems (1 ...

    African Journals Online (AJOL)

    NICO

    2012-09-10

    Sep 10, 2012 ... catalyst to extend its life span, and as reagents for nanomaterials.2,3. The physical properties of ILs such as density, viscosity, melting point, polarity and miscibility with water or molecular solvents, can be finely tuned by changing either the anion or the cation.2–6. ILs have other properties such as very low ...

  16. Third molar infections.

    Science.gov (United States)

    Gutiérrez-Pérez, José Luis

    2004-01-01

    Pericoronitis is an infectious disease often associated with the eruption of a third molar. It can be either acute (serous and suppurative) or chronic. Pain is usually the predominant symptom in acute stages, whereas chronic forms of the disease may display very few symptoms. Both present exudate. The infection is multimicrobial, predominantly caused strictly by betalactamase-producing anaerobeic microorganisms. Treatment measures are symptomatic, antimicrobial and surgical. Antimicrobial treatment is indicated for preoperative prophylaxis when there is a high risk of postoperative infection and, during the acute stages of suppurative pericoronitis when surgery must be postponed. First-line treatment in this case consists of amoxicillin with associated clavulanic acid. Although surgical treatment of pericoronitis presenting at the third molar is indicated as a Grade C recommendation for extraction, it is the most common indication for extraction of a retained third molar, owing to the improved quality of life it can offer the patient.

  17. Excess Enthalpies of Mixing of Binary Mixtures of NaCl, KCl, NaBr ...

    African Journals Online (AJOL)

    NJD

    2004-07-01

    Jul 1, 2004 ... bDepartment of Chemical Engineering, Yonsei University, Seoul 120-749, Korea. ... interactions play a key role in the solution chemistry of solutes.1–6 ..... I = 1.000 mol kg–1. KBr (1) + KCl (2). NaBr (1) + NaCl (2). KBr (1) + NaCl (2). 0.1093. 22. 0.1208. 10. 0.1128. 19. 0.1582. 36. 0.2118. 14. 0.1818. 28.

  18. Hypersonic aerothermodynamic and scramjet research using high enthalpy shock tunnel

    Science.gov (United States)

    Itoh, K.; Ueda, S.; Tanno, H.; Komuro, T.; Sato, K.

    A high enthalpy shock tunnel is a potential facility for gaining knowledge to develop modern aerothermodynamic and propulsion technologies. The largest high enthalpy shock tunnel HIEST was built at NAL Kakuda in 1997, aiming for aerothermodynamic tests of Japan's space vehicle HOPE and scramjet propulsion systems. Selected topics from the experimental studies carried out using HIEST so far, such as the nonequilibrium aerodynamics of HOPE, the surface catalytic effect on aerodynamic heating and scramjet performance are described.

  19. Enthalpy-entropy compensation: the role of solvation.

    Science.gov (United States)

    Dragan, Anatoliy I; Read, Christopher M; Crane-Robinson, Colyn

    2017-05-01

    Structural modifications to interacting systems frequently lead to changes in both the enthalpy (heat) and entropy of the process that compensate each other, so that the Gibbs free energy is little changed: a major barrier to the development of lead compounds in drug discovery. The conventional explanation for such enthalpy-entropy compensation (EEC) is that tighter contacts lead to a more negative enthalpy but increased molecular constraints, i.e., a compensating conformational entropy reduction. Changes in solvation can also contribute to EEC but this contribution is infrequently discussed. We review long-established and recent cases of EEC and conclude that the large fluctuations in enthalpy and entropy observed are too great to be a result of only conformational changes and must result, to a considerable degree, from variations in the amounts of water immobilized or released on forming complexes. Two systems exhibiting EEC show a correlation between calorimetric entropies and local mobilities, interpreted to mean conformational control of the binding entropy/free energy. However, a substantial contribution from solvation gives the same effect, as a consequence of a structural link between the amount of bound water and the protein flexibility. Only by assuming substantial changes in solvation-an intrinsically compensatory process-can a more complete understanding of EEC be obtained. Faced with such large, and compensating, changes in the enthalpies and entropies of binding, the best approach to engineering elevated affinities must be through the addition of ionic links, as they generate increased entropy without affecting the enthalpy.

  20. Experimental formation enthalpies for intermetallic phases and other inorganic compounds

    Science.gov (United States)

    Kim, George; Meschel, S. V.; Nash, Philip; Chen, Wei

    2017-10-01

    The standard enthalpy of formation of a compound is the energy associated with the reaction to form the compound from its component elements. The standard enthalpy of formation is a fundamental thermodynamic property that determines its phase stability, which can be coupled with other thermodynamic data to calculate phase diagrams. Calorimetry provides the only direct method by which the standard enthalpy of formation is experimentally measured. However, the measurement is often a time and energy intensive process. We present a dataset of enthalpies of formation measured by high-temperature calorimetry. The phases measured in this dataset include intermetallic compounds with transition metal and rare-earth elements, metal borides, metal carbides, and metallic silicides. These measurements were collected from over 50 years of calorimetric experiments. The dataset contains 1,276 entries on experimental enthalpy of formation values and structural information. Most of the entries are for binary compounds but ternary and quaternary compounds are being added as they become available. The dataset also contains predictions of enthalpy of formation from first-principles calculations for comparison.

  1. Taurodontism in deciduous molars.

    Science.gov (United States)

    Bafna, Yash; Kambalimath, H V; Khandelwal, Vishal; Nayak, Prathibha

    2013-06-03

    Taurodont teeth are characterised by large pulp chambers at the expense of roots. An enlarged pulp chamber, apical displacement of the pulpal floor and no constriction at the level of the cement-enamel junction are the characteristic features of taurodont tooth. It appears more frequently as an isolated anomaly but its association with syndromes and other abnormalities have also been reported. Permanent dentition is more commonly affected than deciduous dentition. This paper presents a case report of taurodontism in relation to mandibular deciduous second molars.

  2. The reaction enthalpy of hydrogen dissociation calculated with the Small System Method from simulation of molecular fluctuations.

    Science.gov (United States)

    Skorpa, Ragnhild; Simon, Jean-Marc; Bedeaux, Dick; Kjelstrup, Signe

    2014-09-28

    We show how we can find the enthalpy of a chemical reaction under non-ideal conditions using the Small System Method to sample molecular dynamics simulation data for fluctuating variables. This method, created with Hill's thermodynamic analysis, is used to find properties in the thermodynamic limit, such as thermodynamic correction factors, partial enthalpies, volumes, heat capacities and compressibility. The values in the thermodynamic limit at (T,V, μj) are then easily transformed into other ensembles, (T,V,Nj) and (T,P,Nj), where the last ensemble gives the partial molar properties which are of interest to chemists. The dissociation of hydrogen from molecules to atoms was used as a convenient model system. Molecular dynamics simulations were performed with three densities; ρ = 0.0052 g cm(-3) (gas), ρ = 0.0191 g cm(-3) (compressed gas) and ρ = 0.0695 g cm(-3) (liquid), and temperatures in the range; T = 3640-20,800 K. The enthalpy of reaction was observed to follow a quadratic trend as a function of temperature for all densities. The enthalpy of reaction was observed to only have a small pressure dependence. With a reference point close to an ideal state (T = 3640 K and ρ = 0.0052 g cm(-3)), we were able to calculate the thermodynamic equilibrium constant, and thus the deviation from ideal conditions for the lowest density. We found the thermodynamic equilibrium constant to increase with increasing temperature, and to have a negligible pressure dependence. Taking the enthalpy variation into account in the calculation of the thermodynamic equilibrium constant, we found the ratio of activity coefficients to be in the order of 0.7-1.0 for the lowest density, indicating repulsive forces between H and H2. This study shows that the compressed gas- and liquid density values at higher temperatures are far from those calculated under ideal conditions. It is important to have a method that can give access to partial molar properties, independent of the ideality of

  3. Formation enthalpies for transition metal alloys using machine learning

    Science.gov (United States)

    Ubaru, Shashanka; Miedlar, Agnieszka; Saad, Yousef; Chelikowsky, James R.

    2017-06-01

    The enthalpy of formation is an important thermodynamic property. Developing fast and accurate methods for its prediction is of practical interest in a variety of applications. Material informatics techniques based on machine learning have recently been introduced in the literature as an inexpensive means of exploiting materials data, and can be used to examine a variety of thermodynamics properties. We investigate the use of such machine learning tools for predicting the formation enthalpies of binary intermetallic compounds that contain at least one transition metal. We consider certain easily available properties of the constituting elements complemented by some basic properties of the compounds, to predict the formation enthalpies. We show how choosing these properties (input features) based on a literature study (using prior physics knowledge) seems to outperform machine learning based feature selection methods such as sensitivity analysis and LASSO (least absolute shrinkage and selection operator) based methods. A nonlinear kernel based support vector regression method is employed to perform the predictions. The predictive ability of our model is illustrated via several experiments on a dataset containing 648 binary alloys. We train and validate the model using the formation enthalpies calculated using a model by Miedema, which is a popular semiempirical model used for the prediction of formation enthalpies of metal alloys.

  4. Prediction of solvation enthalpy of gaseous organic compounds in propanol

    Science.gov (United States)

    Golmohammadi, Hassan; Dashtbozorgi, Zahra

    2016-09-01

    The purpose of this paper is to present a novel way for developing quantitative structure-property relationship (QSPR) models to predict the gas-to-propanol solvation enthalpy (Δ H solv) of 95 organic compounds. Different kinds of descriptors were calculated for each compound using the Dragon software package. The variable selection technique of replacement method (RM) was employed to select the optimal subset of solute descriptors. Our investigation reveals that the dependence of physical chemistry properties of solution on solvation enthalpy is nonlinear and that the RM method is unable to model the solvation enthalpy accurately. The results established that the calculated Δ H solv values by SVM were in good agreement with the experimental ones, and the performances of the SVM models were superior to those obtained by RM model.

  5. Non-equilibrium theory employing enthalpy-based equation of state for binary solid and porous mixtures

    Science.gov (United States)

    Nayak, B.; Menon, S. V. G.

    2017-04-01

    A generalized enthalpy-based equation of state, which includes thermal electron excitations and non-equilibrium thermal energies, is formulated for binary solid and porous mixtures. Our approach gives rise to an extra contribution to mixture volume, in addition to those corresponding to average mixture parameters. This excess term involves the difference of thermal enthalpies of the two components, which depend on their individual temperatures. We propose to use the Hugoniot of the components to compute non-equilibrium temperatures in the mixture. These are then compared with the average temperature obtained from the mixture Hugoniot, thereby giving an estimate of non-equilibrium effects. The Birch-Murnaghan model for the zero-temperature isotherm and a linear thermal model are then used for applying the method to several mixtures, including one porous case. Comparison with experimental data on the pressure-volume Hugoniot and shock speed versus particle speed shows good agreement.

  6. Enthalpy and phase behavior of coal derived liquid mixtures: Technical progress report for the period January-March 1987. [M-cresol/quinoline/tetralin ternary mixture

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1987-04-30

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. The objectives of this program are to study the enthalpy and phase behavior of a selected ternary model compound system, representative of interactions present in coal derived liquids. Measurements will be made in a Freon 11 reference fluid boil-off calorimeter, and an equilibrium flash vaporization apparatus. These experimental systems have already been developed. Previous studies have indicated that existing data and correlations developed for petroleum fluids are not applicable to coal derived liquids. This is due to the presence of significant concentrations of polar associating heteroatomics in the predominantly aromatic coal liquids. Thus, the ternary system will include an aromatic, a basic nitrogen compound, and a cresol. It is presently planned to study the m-cresol/quinoline/tetralin ternary mixture. Measurements will be made over a wide range of temperature (200 to 750/sup 0/F) and pressure (20 to 1500 psia), for the three pure compounds, the three binary mixtures and selected compositions of the ternary. Both enthalpy and phase behavior measurements will be made. This set of data will be useful as a standard for fitting and evaluating thermodynamic correlations and equations of state that are applicable to associating fluid mixtures, and thus to coal derived liquids. In particular we will attempt to fit both the enthalpy and phase behavior data with a single equation of state using local composition mixing rules and common interaction parameters. During the eleventh quarter, enthalpy measurements have been obtained for the ternary mixtures of m-cresol/quinoline/tetralin with molar ratios 2/3:1/6:1/6 and 1/6:2/3:1/6 m-cresol:quinoline:tetralin. The results are presented in Appendix A. The project has progressed very will during this quarter, and the enthalpy measurements have been completed. 2 refs., 2 figs., 2 tabs.

  7. Enthalpy of mixing of liquid Al-Cu-Si alloys

    Energy Technology Data Exchange (ETDEWEB)

    Witusiewicz, V.T.; Arpshofen, I.; Seifert, H.-J.; Aldinger, F. [Max-Planck Inst. fur Metallforschung, Stuttgart (Germany). Inst. fur Nichtmetallische Anorganische Mater.

    2000-02-02

    The partial and the integral enthalpies of mixing of liquid Al-Cu-Si alloys have been measured by high temperature calorimetry at 1575{+-}3 K. Results for three sections with constant concentration ratios of Al and Si are given in tabular form. (orig.)

  8. Modified enthalpy method for the simulation of melting and ...

    Indian Academy of Sciences (India)

    face obtained is compared satisfactorily with the experimental results available in literature. Keywords. Melting; enthalpy method; wavy interface; mushy zone constant. 1. Introduction. The study of melting and solidification offers insights in the design of casting, welding, latent thermal energy storage systems, etc., and in the ...

  9. Enthalpy and void distributions in subchannels of PHWR fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Choi, H.; Rhee, B. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)

  10. MOLAR TOOTH SIGN - JOUBERT SYNDROME

    Directory of Open Access Journals (Sweden)

    Dušica Ranđelović

    2015-09-01

    Full Text Available The molar tooth sign is seen in very few conditions and is a very rare pediatric central nervous system congenital anomaly. Molar tooth sign is the result of cerebellar vermis hypoplasia, thick and maloriented superior cerebellar peduncles, and an abnormally deep interpeduncular fossa. In Joubert syndrome, this is seen in about 85% of patients. We present a case of a two-year old girl with flaccid paraparesis, regression of milestones and developmental delay. Magnetic resonance imaging (MRI showed the characteristic molar tooth sign with apposition of cerebellar hemispheres, batwing-shaped fourth ventricle, cerebellar vermis agenesis and deep interpeduncular fossa consistent with the diagnosis of Joubert syndrome.

  11. Enthalpies of Vaporization of Organic and Organometallic Compounds, 1880–2002

    National Research Council Canada - National Science Library

    Chickos, James S; Acree, William E

    2003-01-01

    A compendium of vaporization enthalpies published within the period 1910–2002 is reported. A brief review of temperature adjustments of vaporization enthalpies from temperature of measurement to the standard reference temperature...

  12. Molar Intrusion in Open-bite Adults Using Zygomatic Miniplates.

    Science.gov (United States)

    Marzouk, Eiman S; Abdallah, Essam Mohamed; El-Kenany, Walid A

    2015-01-01

    The aim of this study is to evaluate the skeletal, dental and soft tissue changes that arise after intrusion of the maxillary molars using zygomatic miniplates in adult skeletal anterior open bite patients. In addition to measuring the amount and rate of molar intrusion; with special emphasis on changes in the axial inclination of the intruded molars. The study group was composed of 13 anterior open bite patients (mean age 18 years, 8 months ± 2 years, 2 months) with posterior dentoalveolar excess. Mini-plates were placed in the zygomatic buttress bilaterally. The upper arch was segmentally leveled and a double Trans-Palatal Arch (TPA) was bonded. Closed NiTi coil spring was placed bilaterally between the book of the mini-plate just mesial and distal to the first molar buccal tube applying intrusive force of 450 gper side. Lateral and posteroanterior cephalograms were taken before intrusion (T1: post upper segmental leveling) and after intrusion (T2). Comparison between means before and after the intrusion was done using Wilcoxon Signed Ranks test (WSRT). Mandibular autorotation followed the molar intrusion, SNB and SN-Pog angles significantly increased while the ANB, MP-SN angle and N-S-Gn angle significantly decreased. The mean amount of accomplished molar intrusion was 3.1mm ± 0.74mm, with a rate of 0.36mm per month ± 0.08mm per month and a bite closure of 6.55mm ± 1.83mm. There was no significant buccal tip in the right and left molars upon intrusion. Conclusion: Miniplates zygomatic anchorage can be used effectively for skeletal open bite correction through posterior dento-alveolar intrusion. Intrusion of the posterior teeth with skeletal anchorage induced counterclockwise rotation of the mandible and, as a consequence, corrected the anteroposterior intermaxillary relationship with a dramatic improvement in the facial soft tissue convexity.

  13. Estimating the melting point, entropy of fusion, and enthalpy of ...

    Science.gov (United States)

    The entropies of fusion, enthalies of fusion, and melting points of organic compounds can be estimated through three models developed using the SPARC (SPARC Performs Automated Reasoning in Chemistry) platform. The entropy of fusion is modeled through a combination of interaction terms and physical descriptors. The enthalpy of fusion is modeled as a function of the entropy of fusion, boiling point, and fexibility of the molecule. The melting point model is the enthlapy of fusion divided by the entropy of fusion. These models were developed in part to improve SPARC's vapor pressure and solubility models. These models have been tested on 904 unique compounds. The entropy model has a RMS of 12.5 J mol-1K-1. The enthalpy model has a RMS of 4.87 kJ mol-1. The melting point model has a RMS of 54.4°C. Published in the journal, SAR and QSAR in Environmental Research

  14. Corollary from the Exact Expression for Enthalpy of Vaporization

    Directory of Open Access Journals (Sweden)

    A. A. Sobko

    2011-01-01

    Full Text Available A problem on determining effective volumes for atoms and molecules becomes actual due to rapidly developing nanotechnologies. In the present study an exact expression for enthalpy of vaporization is obtained, from which an exact expression is derived for effective volumes of atoms and molecules, and under certain assumptions on the form of an atom (molecule it is possible to find their linear dimensions. The accuracy is only determined by the accuracy of measurements of thermodynamic parameters at the critical point.

  15. Modular enthalpy probe and gas analyzer for thermal plasma measurements

    Science.gov (United States)

    Swank, W. D.; Fincke, J. R.; Haggard, D. C.

    1993-01-01

    The enthalpy or calorimetric probe is a water-cooled stagnation/sampling probe for studying the temperature, velocity, and composition of hot-gas flow fields. In order to derive the thermodynamic properties of complex flow fields such as plasma arc jets or high-velocity oxygen fuel jets, the specie concentration must be known accurately. To this end a differentially pumped quadrapole mass spectrometer has been integrated with a fully automated enthalpy probe system. An inexpensive modular probe is described along with the system and its theory of operation. Calibration and error are also discussed. Typical results are presented for the system operating in an argon/helium plasma arc jet in atmospheric pressure air. The maximum temperature measured is 13434 K on the center line of the jet, 5 mm from the exit, with a corresponding velocity of 1295 m/s. The utility in integrating the mass spectrometer to the enthalpy probe system is not only an accurate measurement of the gas mixture components for obtaining the correct property information, but also valuable information can be obtained about demixing diffusion and chemical reaction taking place in the plasma plume. The relative amount of argon to helium is shown to deviate from the nominal mixture by as much as 40% at the center of the plume.

  16. Formation enthalpies by mixing GGA and GGA + U calculations

    Science.gov (United States)

    Jain, Anubhav; Hautier, Geoffroy; Ong, Shyue Ping; Moore, Charles J.; Fischer, Christopher C.; Persson, Kristin A.; Ceder, Gerbrand

    2011-07-01

    Standard approximations to the density functional theory exchange-correlation functional have been extraordinary successful, but calculating formation enthalpies of reactions involving compounds with both localized and delocalized electronic states remains challenging. In this work we examine the shortcomings of the generalized gradient approximation (GGA) and GGA+U in accurately characterizing such difficult reactions. We then outline a methodology that mixes GGA and GGA+U total energies (using known binary formation data for calibration) to more accurately predict formation enthalpies. We demonstrate that for a test set of 49 ternary oxides, our methodology can reduce the mean absolute relative error in calculated formation enthalpies from approximately 7.7-21% in GGA+U to under 2%. As another example we show that neither GGA nor GGA+U alone accurately reproduces the Fe-P-O phase diagram; however, our mixed methodology successfully predicts all known phases as stable by naturally stitching together GGA and GGA+U results. As a final example we demonstrate how our technique can be applied to the calculation of the Li-conversion voltage of LiFeF3. Our results indicate that mixing energies of several functionals represents one avenue to improve the accuracy of total energy computations without affecting the cost of calculation.

  17. Excessive Daytime Sleepiness

    Directory of Open Access Journals (Sweden)

    Yavuz Selvi

    2016-06-01

    Full Text Available Excessive daytime sleepiness is one of the most common sleep-related patient symptoms, with preva-lence in the community estimated to be as high as 18%. Patients with excessive daytime sleepiness may exhibit life threatening road and work accidents, social maladjustment, decreased academic and occupational performance and have poorer health than comparable adults. Thus, excessive daytime sleepiness is a serious condition that requires investigation, diagnosis and treatment primarily. As with most medical condition, evaluation of excessive daytime sleepiness begins a precise history and various objective and subjective tools have been also developed to assess excessive daytime sleepiness. The most common causes of excessive daytime sleepiness are insufficient sleep hygiene, chronic sleep deprivation, medical and psychiatric conditions and sleep disorders, such as obstructive sleep apnea, medications, and narcolepsy. Treatment option should address underlying contributors and promote sleep quantity by ensuring good sleep hygiene. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(2: 114-132

  18. Enthalpy model for heating, melting, and vaporization in laser ablation

    Directory of Open Access Journals (Sweden)

    Vasilios Alexiades

    2010-09-01

    Full Text Available Laser ablation is used in a growing number of applications in various areas including medicine, archaeology, chemistry, environmental and materials sciences. In this work the heat transfer and phase change phenomena during nanosecond laser ablation of a copper (Cu target in a helium (He background gas at atmospheric pressure are presented. An enthalpy model is outlined, which accounts for heating, melting, and vaporization of the target. As far as we know, this is the first model that connects the thermodynamics and underlying kinetics of this challenging phase change problem in a self-consistent way.

  19. Prevention of excess gain.

    Science.gov (United States)

    Stevens, J; Truesdale, K P; Wang, C-H; Cai, J

    2009-11-01

    Obesity prevention trials are designed to promote healthy weight. The success of these trials is often assessed using one of three metrics--means, incidence or prevalence. In this study, we point out conceptual shortcomings of these metrics and introduce an alternative that we call 'excess gain'. A mathematical demonstration using simulated data shows a scenario in which the statistical power of excess gain compares favorably with that of incidence and prevalence. Prevention of excess gain communicates an easily understood public health message that is applicable to all individuals regardless of weight status.

  20. Kinetics and enthalpy of crystallization of uric acid dihydrate

    Energy Technology Data Exchange (ETDEWEB)

    Sádovská, Galina, E-mail: galina.sadovska@upce.cz; Honcová, Pavla; Sádovský, Zdeněk

    2013-08-20

    Highlights: • The kinetic constant and growth order of crystallization of uric acid dihydrate was calculated. • The equation describing first-order crystal growth was derived. • The enthalpy of crystallization of uric acid dihydrate was determined. - Abstract: The kinetics of crystallization of uric acid dihydrate in aqueous solution with a constant ionic strength 0.3 mol dm{sup −3} NaCl and at thermodynamic and physiological temperature (25 and 37 °C) was studied using isoperibolic reaction twin calorimeter. The enthalpy of crystallization Δ{sub cr}H = −47.3 ± 0.9 and −46.2 ± 1.4 kJ mol{sup −1}and kinetic constant k{sub g} = 2.0 × 10{sup −8} and 9.6 × 10{sup −8} m{sup 4} s{sup −1} mol{sup −1} were determined at 25 and 37 °C, respectively.

  1. Excess wind power

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2005-01-01

    analyses it is analysed how excess productions are better utilised; through conversion into hydrogen of through expansion of export connections thereby enabling sales. The results demonstrate that particularly hydrogen production is unviable under current costs but transmission expansion could...

  2. Supernumerary molars. A review of 53 cases

    OpenAIRE

    Menardía Pejoan, V.; Berini Aytés, Leonardo; Gay Escoda, Cosme

    2000-01-01

    Supernumerary molars are not uncommon and may be found nearly anywhere in the dental alveolar arches. A series of 36 patients that presented with 53 supernumerary molars are reviewed. They occurred more frequently in the maxilla (86.8%), had little or no clinical significance, tended to be impacted, and were not associated with the impactation of the third molar. Four cases of maxillary fifth molars are described

  3. Impacted lower third molars and distal caries in the mandibular second molar. Is prophylactic removal of lower third molars justified?

    Science.gov (United States)

    Marques, José; Montserrat-Bosch, Marta; Vilchez-Pérez, Miguel-Angel; Valmaseda-Castellón, Eduard; Gay-Escoda, Cosme

    2017-01-01

    Background The objective of this study was to evaluate the association between the presence of mandibular third molars and the occurrence of carious lesions in the distal aspect of the mandibular second molar. Material and Methods A retrospective cohort study comprising 327 lower third molars extracted in the Oral Surgery and Implantology Master’s Degree program of the School of Dentistry of the University of Barcelona (Barcelona, Spain) was carried out. A descriptive and bivariate analysis was made. The diagnosis of caries in the second molar and the position of the mandibular third molar were evaluated through panoramic radiographies. Results The sample included 203 patients, 94 males (46.3%) and 109 females (53.7%), with a mean age of 26,8 years and 327 lower third molars. The prevalence of second molar distal caries was 25.4% (95% CI= 20.6% to 30.2%). This pathology was significantly more frequent when the third molar was in a horizontal position (27.7%), when the contact point was at (45,8%) or below (47.0%) the cementoenamel junction (CEJ), and when the distal CEJ of the mandibular second molar and the mesial CEJ of the third molar was 7 to 12 mm apart. Conclusions Horizontal lower third molars with contact points at or below the CEJ are more likely to produce distal caries in the mandibular second molars. Due to the high prevalence of this pathology (20.6% to 30.2%), a prophylactic removal of lower third molars with the above-mentioned features might be advisable. Key words:Second molar, caries, third molar, prophylactic removal. PMID:28638558

  4. Capacitive Detection of Low-Enthalpy, Higher-Order Phase Transitions in Synthetic and Natural Composition Lipid Membranes.

    Science.gov (United States)

    Taylor, Graham J; Heberle, Frederick A; Seinfeld, Jason S; Katsaras, John; Collier, C Patrick; Sarles, Stephen A

    2017-09-26

    In-plane lipid organization and phase separation in natural membranes play key roles in regulating many cellular processes. Highly cooperative, first-order phase transitions in model membranes consisting of few lipid components are well understood and readily detectable via calorimetry, densitometry, and fluorescence. However, far less is known about natural membranes containing numerous lipid species and high concentrations of cholesterol, for which thermotropic transitions are undetectable by the above-mentioned techniques. We demonstrate that membrane capacitance is highly sensitive to low-enthalpy thermotropic transitions taking place in complex lipid membranes. Specifically, we measured the electrical capacitance as a function of temperature for droplet interface bilayer model membranes of increasing compositional complexity, namely, (a) a single lipid species, (b) domain-forming ternary mixtures, and (c) natural brain total lipid extract (bTLE). We observed that, for single-species lipid bilayers and some ternary compositions, capacitance exhibited an abrupt, temperature-dependent change that coincided with the transition detected by other techniques. In addition, capacitance measurements revealed transitions in mixed-lipid membranes that were not detected by the other techniques. Most notably, capacitance measurements of bTLE bilayers indicated a transition at ∼38 °C not seen with any other method. Likewise, capacitance measurements detected transitions in some well-studied ternary mixtures that, while known to yield coexisting lipid phases, are not detected with calorimetry or densitometry. These results indicate that capacitance is exquisitely sensitive to low-enthalpy membrane transitions because of its sensitivity to changes in bilayer thickness that occur when lipids and excess solvent undergo subtle rearrangements near a phase transition. Our findings also suggest that heterogeneity confers stability to natural membranes that function near

  5. Third molar complications requiring hospitalization.

    Science.gov (United States)

    Kunkel, Martin; Morbach, Thomas; Kleis, Wilfried; Wagner, Wilfried

    2006-09-01

    The aim of this study was to describe demographic and clinical patterns of subjects hospitalized with complications associated with third molars (M3). The investigation was designed as a prospective cohort study composed of subjects admitted to hospital for management of M3-associated complications. The predictor variable was "clinical status of the M3" defined as (A) prophylactic M3 removal, (B) nonelective M3 removal, or (C) M3 present at the time of admission. Outcome variables were infection parameters, treatment costs, length of hospital stay, and days of disability. Postoperative complications (A and B) were compared to complications based on pericoronitis (C). Complications due to prophylactic removal (A) were compared to those arising from pericoronitis or from the removal of symptomatic teeth (B and C). From January 2003 to December 2004, 45 deep space infections, 6 mandibular fractures, 2 lingual nerve injuries, 1 parapharyngeal tooth luxation, and 1 osteomyelitis were noticed. Fifteen complications resulted from prophylactic surgery (A), 25 from nonelective removal (B), and 15 from pericoronitis (C). Direct treatment costs were 147,000 euro (A: 42,000 euro; B: 74,000 euro; C: 31,000 euro). In 10 of the 15 patients of group C, deep space involvement resulted immediately from the first episode of pericoronitis. Neither clinical markers of infection nor economic parameters showed significant differences between the groups. Within the catchment area of our institution, the majority of third molar-related hospitalizations resulted from diseased third molars or their removal.

  6. Accounting for apparent deviations between calorimetric and van't Hoff enthalpies.

    Science.gov (United States)

    Kantonen, Samuel A; Henriksen, Niel M; Gilson, Michael K

    2017-12-05

    In theory, binding enthalpies directly obtained from calorimetry (such as ITC) and the temperature dependence of the binding free energy (van't Hoff method) should agree. However, previous studies have often found them to be discrepant. Experimental binding enthalpies (both calorimetric and van't Hoff) are obtained for two host-guest pairs using ITC, and the discrepancy between the two enthalpies is examined. Modeling of artificial ITC data is also used to examine how different sources of error propagate to both types of binding enthalpies. For the host-guest pairs examined here, good agreement, to within about 0.4kcal/mol, is obtained between the two enthalpies. Additionally, using artificial data, we find that different sources of error propagate to either enthalpy uniquely, with concentration error and heat error propagating primarily to calorimetric and van't Hoff enthalpies, respectively. With modern calorimeters, good agreement between van't Hoff and calorimetric enthalpies should be achievable, barring issues due to non-ideality or unanticipated measurement pathologies. Indeed, disagreement between the two can serve as a flag for error-prone datasets. A review of the underlying theory supports the expectation that these two quantities should be in agreement. We address and arguably resolve long-standing questions regarding the relationship between calorimetric and van't Hoff enthalpies. In addition, we show that comparison of these two quantities can be used as an internal consistency check of a calorimetry study. Copyright © 2017. Published by Elsevier B.V.

  7. Measurement and correlation of the enthalpy of coal-derived liquids

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, R.; Kidnay, A.J.; Yesavage, V.F.

    1982-03-01

    An apparatus termed the Freon 11 reference fluid boil-off calorimeter described in previous publication is illustrated, and enthalpy data obtained with the calorimeter for numerous coal-derived liquid samples are tabulated. Enthalpy data for certain model compounds representative of the coal-derived liquids are presented for comparison. Association of heteroatomic compounds in coal-derived liquids appeared to cause positive errors in the enthalpy data. A method of determining the degree of association from the slope of the molecular weight versus the concentration curve appears to be applicable to the correction of the enthalpy data. 17 refrerences. (BLM)

  8. Application of enthalpy model for floating zone silicon crystal growth

    Science.gov (United States)

    Krauze, A.; Bergfelds, K.; Virbulis, J.

    2017-09-01

    A 2D simplified crystal growth model based on the enthalpy method and coupled with a low-frequency harmonic electromagnetic model is developed to simulate the silicon crystal growth near the external triple point (ETP) and crystal melting on the open melting front of a polycrystalline feed rod in FZ crystal growth systems. Simulations of the crystal growth near the ETP show significant influence of the inhomogeneities of the EM power distribution on the crystal growth rate for a 4 in floating zone (FZ) system. The generated growth rate fluctuations are shown to be larger in the system with higher crystal pull rate. Simulations of crystal melting on the open melting front of the polycrystalline rod show the development of melt-filled grooves at the open melting front surface. The distance between the grooves is shown to grow with the increase of the skin-layer depth in the solid material.

  9. Changes of enthalpy slope in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Collado, Francisco J.; Monne, Carlos [Universidad de Zaragoza-CPS, Departamento de Ingenieria Mecanica-Motores Termicos, Zaragoza (Spain); Pascau, Antonio [Universidad de Zaragoza-CPS, Departamento de Ciencia de los Materiales y Fluidos-Mecanica de Fluidos, Zaragoza (Spain)

    2006-03-01

    Void fraction data in subcooled flow boiling of water at low pressure measured by General Electric in the 1960s are analyzed following the classical model of Griffith et al. (in Proceedings of ASME-AIChE heat transfer conference, 58-HT-19, 1958). In addition, a new proposal for analyzing one-dimensional steady flow boiling is used. This is based on the physical fact that if the two phases have different velocities, they cannot cover the same distance - the control volume length - in the same time. So a slight modification of the heat balance is suggested, i.e., the explicit inclusion of the vapor-liquid velocity ratio or slip ratio as scaling time factor between the phases, which is successfully checked against the data. Finally, the prediction of void fraction using correlations of the net rate of change of vapor enthalpy in the fully developed regime of subcooled flow boiling is explored. (orig.)

  10. Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins

    DEFF Research Database (Denmark)

    Fago, A.; Wells, R.M.G.; Weber, Roy E.

    1997-01-01

    The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff plot...... oxygen binding. The degree of the temperature dependence of the heat of oxygenation observed in these hemoglobins seems to reflect the differences in their allosteric effects rather than a specific molecular adaptation to low temperatures. Moreover, this study indicates that the disagreement between...... (logP(50) vs 1/T) of D. mawsoni hemoglobin indicates that the enthalpy of oxygenation (slope of the plot) is temperature dependent and that at high temperatures oxygen-binding becomes less exothermic. Nearly linear relationships were found in the hemoglobins of the other two species. The data were...

  11. Molecular rigidity and enthalpy-entropy compensation in DNA melting.

    Science.gov (United States)

    Vargas-Lara, Fernando; Starr, Francis W; Douglas, Jack F

    2017-10-23

    Enthalpy-entropy compensation (EEC) is observed in diverse molecular binding processes of importance to living systems and manufacturing applications, but this widely occurring phenomenon is not sufficiently understood from a molecular physics standpoint. To gain insight into this fundamental problem, we focus on the melting of double-stranded DNA (dsDNA) since measurements exhibiting EEC are extensive for nucleic acid complexes and existing coarse-grained models of DNA allow us to explore the influence of changes in molecular parameters on the energetic parameters by using molecular dynamics simulations. Previous experimental and computational studies have indicated a correlation between EEC and changes in molecular rigidity in certain binding-unbinding processes, and, correspondingly, we estimate measures of DNA molecular rigidity under a wide range of conditions, along with resultant changes in the enthalpy and entropy of binding. In particular, we consider variations in dsDNA rigidity that arise from changes of intrinsic molecular rigidity such as varying the associative interaction strength between the DNA bases, the length of the DNA chains, and the bending stiffness of the individual DNA chains. We also consider extrinsic changes of molecular rigidity arising from the addition of polymer additives and geometrical confinement of DNA between parallel plates. All our computations confirm EEC and indicate that this phenomenon is indeed highly correlated with changes in molecular rigidity. However, two distinct patterns relating to how DNA rigidity influences the entropy of association emerge from our analysis. Increasing the intrinsic DNA rigidity increases the entropy of binding, but increases in molecular rigidity from external constraints decreases the entropy of binding. EEC arises in numerous synthetic and biological binding processes and we suggest that changes in molecular rigidity might provide a common origin of this ubiquitous phenomenon in the mutual

  12. Excessive crying in infants

    Directory of Open Access Journals (Sweden)

    Ricardo Halpern

    2016-06-01

    Full Text Available ABSTRACT Objective: Review the literature on excessive crying in young infants, also known as infantile colic, and its effects on family dynamics, its pathophysiology, and new treatment interventions. Data source: The literature review was carried out in the Medline, PsycINFO, LILACS, SciELO, and Cochrane Library databases, using the terms “excessive crying,” and “infantile colic,” as well technical books and technical reports on child development, selecting the most relevant articles on the subject, with emphasis on recent literature published in the last five years. Summary of the findings: Excessive crying is a common symptom in the first 3 months of life and leads to approximately 20% of pediatric consultations. Different prevalence rates of excessive crying have been reported, ranging from 14% to approximately 30% in infants up to 3 months of age. There is evidence linking excessive crying early in life with adaptive problems in the preschool period, as well as with early weaning, maternal anxiety and depression, attention deficit hyperactivity disorder, and other behavioral problems. Several pathophysiological mechanisms can explain these symptoms, such as circadian rhythm alterations, central nervous system immaturity, and alterations in the intestinal microbiota. Several treatment alternatives have been described, including behavioral measures, manipulation techniques, use of medication, and acupuncture, with controversial results and effectiveness. Conclusion: Excessive crying in the early months is a prevalent symptom; the pediatrician's attention is necessary to understand and adequately manage the problem and offer support to exhausted parents. The prescription of drugs of questionable action and with potential side effects is not a recommended treatment, except in extreme situations. The effectiveness of dietary treatments and use of probiotics still require confirmation. There is incomplete evidence regarding alternative

  13. CANINE ECTOPIC TREATMENT WITH FIRST MOLAR EXTRACTION

    Directory of Open Access Journals (Sweden)

    Angelica Margo

    2015-06-01

    Full Text Available Decision to extract or not and the type of tooth must be analyzed carefully in orthodontic treatment. Preferable tooth to be extracted was the tooth with large caries or restoration. Usually the type of tooth to be extracted was second molar (if the third molar appears, incisor, first molar, and combination of several teeth. Orthodontic treatment with molar extraction is more difficult to treat and the result is usually compromise. There are several considerations in extracting first molar such as tooth with large caries or restoration, hypoplasia, periapical disease, large discrepancy, high maxilla-mandibular plane angle, and cases with anterior open bite. Nowadays, orthodontic cases with molar extraction do not prolong the treatment time compared to premolar extraction case, but the anchorage system must be considered carefully. The present case was treated with extraction of first molar to solve anterior crowding with maximum anchorage at the upper jaw and using Nance Holding Appliance.

  14. Reducing Excessive Television Viewing.

    Science.gov (United States)

    Jason, Leonard A.; Rooney-Rebeck, Patty

    1984-01-01

    A youngster who excessively watched television was placed on a modified token economy: earned tokens were used to activate the television for set periods of time. Positive effects resulted in the child's school work, in the amount of time his family spent together, and in his mother's perception of family social support. (KH)

  15. HIV Excess Cancers JNCI

    Science.gov (United States)

    In 2010, an estimated 7,760 new cancers were diagnosed among the nearly 900,000 Americans known to be living with HIV infection. According to the first comprehensive study in the United States, approximately half of these cancers were in excess of what wo

  16. Anaesthetic Challenges in Molar Pregnancy

    Directory of Open Access Journals (Sweden)

    Ghansham Biyani

    2013-06-01

    Full Text Available Gestational Trophoblastic Disease (GTD is a spectrum of tumours with a wide range of biologic behaviour and potential for metastases, which were often fatal in the past. However, with better understanding of patho-physiology in the last few years, most women can now be cured. A Hydatidiform Mole (or Molar Pregnancy is a benign Gestational Trophoblastic Disease that originates from the placenta. Treatment consists of vacuum evacuation but rarely hysterectomy may be required. Anaesthetic management is often complicated by the associated derangements.

  17. Experimental study on an innovative enthalpy recovery technology based on indirect flash evaporative cooling

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Yuan, Shu; Fang, Lei

    2018-01-01

    An indirect flash evaporative cooling enthalpy recovery technology used for building ventilation was proposed based on counter flow plate heat exchanger combing with ultrasonic atomizer. The technology is aimed at enhancing enthalpy recover efficiency and preventing contaminant transfer of heat r...

  18. Effect of cure cycle on enthalpy relaxation and post shrinkage in neat epoxy and epoxy composites

    DEFF Research Database (Denmark)

    Jensen, Martin; Jakobsen, Johnny

    2016-01-01

    The effect of cure cycle on enthalpy relaxation and warpage is studied for both neat epoxy and glass/epoxy composites. An approach for determining the enthalpy relaxation in the matrix of composite materials combining modulated differential scanning calorimetry and thermogravimetry is presented...

  19. The otherness of sexuality: excess.

    Science.gov (United States)

    Stein, Ruth

    2008-03-01

    The present essay, the second of a series of three, aims at developing an experience-near account of sexuality by rehabilitating the idea of excess and its place in sexual experience. It is suggested that various types of excess, such as excess of excitation (Freud), the excess of the other (Laplanche), excess beyond symbolization and the excess of the forbidden object of desire (Leviticus; Lacan) work synergistically to constitute the compelling power of sexuality. In addition to these notions, further notions of excess touch on its transformative potential. Such notions address excess that shatters psychic structures and that is actively sought so as to enable new ones to evolve (Bersani). Work is quoted that regards excess as a way of dealing with our lonely, discontinuous being by using the "excessive" cosmic energy circulating through us to achieve continuity against death (Bataille). Two contemporary analytic thinkers are engaged who deal with the object-relational and intersubjective vicissitudes of excess.

  20. Excessive crying in infants

    Directory of Open Access Journals (Sweden)

    Ricardo Halpern

    2016-05-01

    Conclusion: Excessive crying in the early months is a prevalent symptom; the pediatrician's attention is necessary to understand and adequately manage the problem and offer support to exhausted parents. The prescription of drugs of questionable action and with potential side effects is not a recommended treatment, except in extreme situations. The effectiveness of dietary treatments and use of probiotics still require confirmation. There is incomplete evidence regarding alternative treatments such as manipulation techniques, acupuncture, and use of the herbal supplements and behavioral interventions.

  1. Implications of the enthalpy flux carried by powerful quasar jets

    Science.gov (United States)

    Schwartz, Daniel; Marshall, Herman L.; Worrall, Diana; Birkinshaw, Mark; Perlman, Eric; Lovell, James; Jauncey, David; Murphy, David; Gelbord, Jonathan; Godfrey, Leith; Bicknell, Geoffrey Vincent

    2015-08-01

    We have detected 31 X-ray jets as counterparts to radio jets observed in a survey of 54 quasars (Marshall et al., 2005; 2011). With the most likely interpretation that the X-rays result from inverse Compton boosting of the cosmic microwave background photons, one can estimate the rest frame magnetic field strength, and the particle energy density via the minimum total energy assumption. To reconcile these quantities so that the same spectrum of electrons produces the GHz radio synchrotron emission and its extension to lower energy produces the X-ray, the jets must be in relativistic motion. Another approximation, for example that the bulk Lorentz factor of the jet equals the Doppler factor, is needed to estimate the Lorentz factor. That cannot becorrect for individual jets, but for the ensemble of 31 objects it results in reasonable estimates for the angle of the jet to the line of sight. We can then calculate the enthalpy flux of these jets, which are typically (5--10) x 10^46 erg/s if protons balance the electron charge, and about 5 times smaller if the jets contain only electronsand positrons. Either case represents a signficant, and sometimes dominant, portion of the Eddington luminosity of the black hole.

  2. An automated flow calorimeter for heat capacity and enthalpy measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sandarusi, J.A.; Yesavage, V.F.

    1988-11-01

    An automated flow calorimeter has been developed for the measurement of heat capacity and latent enthalpies of fluids at elevated temperatures (300-700 K) and pressure (< 30 MPa) with a design accuracy of 0.1%. The method of measurement is the traditional electrical power input flow calorimeter, utilizing a precision metering pump, which eliminates the need for flow-rate monitoring. The calorimeter cell uses a unique concentric coil design with passive metal radiation shields and active guard heaters to minimize heat leakage, eliminate the traditional constant-temperature bath, and facilitate easy component replacement. An additional feature of the instrument is a complete automation system, greatly simplifying operation of the apparatus. A novel multitasking software scheme allows a single microcomputer simultaneously to control all system temperatures, provide continuous monitoring and updates on system status, and log data. Preliminary results for liquid water mean heat capacities show the equipment to be performing satisfactorily, with data accuracies of better than /plus minus/0.3%. Minor equipment modifications and better thermometry are required to reduce systemic errors and to achieve the designed operational range.

  3. Moderate point: Balanced entropy and enthalpy contributions in soft matter

    Science.gov (United States)

    He, Baoji; Wang, Yanting

    2017-03-01

    Various soft materials share some common features, such as significant entropic effect, large fluctuations, sensitivity to thermodynamic conditions, and mesoscopic characteristic spatial and temporal scales. However, no quantitative definitions have yet been provided for soft matter, and the intrinsic mechanisms leading to their common features are unclear. In this work, from the viewpoint of statistical mechanics, we show that soft matter works in the vicinity of a specific thermodynamic state named moderate point, at which entropy and enthalpy contributions among substates along a certain order parameter are well balanced or have a minimal difference. Around the moderate point, the order parameter fluctuation, the associated response function, and the spatial correlation length maximize, which explains the large fluctuation, the sensitivity to thermodynamic conditions, and mesoscopic spatial and temporal scales of soft matter, respectively. Possible applications to switching chemical bonds or allosteric biomachines determining their best working temperatures are also briefly discussed. Project supported by the National Basic Research Program of China (Grant No. 2013CB932804) and the National Natural Science Foundation of China (Grant Nos. 11274319 and 11421063).

  4. Pulpectomy procedures in primary molar teeth

    OpenAIRE

    Hany Mohamed Aly Ahmed

    2014-01-01

    Premature loss of primary molars can cause a number of undesirable consequences including loss of arch length, insufficient space for erupting premolars and mesial tipping of the permanent molars. Pulpectomy of primary molar teeth is considered as a reasonable treatment approach to ensure either normal shedding or a long-term survival in instances of retention. Despite being a more conservative treatment option than extraction, efficient pulpectomy of bizarre and tortuous root canals encased ...

  5. Mandibular lip bumper for molar torque control.

    Science.gov (United States)

    Celentano, Giuseppe; Longobardi, Annalisa; Cannavale, Rosangela; Perillo, Letizia

    2011-01-01

    Treatment effects of lip bumpers alone include flaring of the mandibular incisors, distalization and uprighting of the mandibular first molars, and buccal expansion of the canines, premolars, and molar. Lip forces are transmitted through this appliance onto the molars. Moreover the lip bumper is able to derotate, expand or constrict, upright and reinforce the anchorage whereas torque control is lacking. Aim of this paper is the presentation of a new type of lip bumper that allows the molar torque control. Copyright © 2011 Società Italiana di Ortodonzia SIDO. Published by Elsevier Srl. All rights reserved.

  6. Permanent molars: Delayed development and eruption

    Directory of Open Access Journals (Sweden)

    Arathi R

    2006-05-01

    Full Text Available Delayed development and eruption of all the permanent molars is a rare phenomenon, which can cause disturbance in the developing occlusion. The eruption of permanent first and second molars is very important for the coordination of facial growth and for providing sufficient occlusal support for undisturbed mastication. In the case described, the first permanent molars were delayed in their development and were seen erupting at the age of nine and a half years. Severe disparity between the left and the right side of the dentition with respect to the rate of development of molars were also present.

  7. Assessment of association between molar incisor hypomineralization and hypomineralized second primary molar

    National Research Council Canada - National Science Library

    Rakesh Mittal; Shweta Chandak; Manisha Chandwani; Prabhat Singh; Jitesh Pimpale

    2016-01-01

      Background: The term molar incisor hypomineralization (MIH) has been described as a clinical entity of systemic origin affecting the enamel of one or all first permanent molars and also the incisors...

  8. [Hyperthyroidism induced by molar pregnancy].

    Science.gov (United States)

    Laurent, V; Besson, L; Doussin, J F; Rondelet, B; Banssillon, V

    1993-01-01

    A case is reported of a Senegalese patient admitted for hydatiform mole. The serum human chorionic gonadotrophin concentration (hCG) was 900,000 UI.l-1. The patient was recognized to be clinically hyperthyroid with raised T4 and T3 values, but a very low TSH concentration. After two days of beta adrenergic blockade and carbimazole, a suction curettage was performed under general anaesthesia. Propranolol was again administered 6 hours after the surgery. Thyroid function returned to normal level two weeks after removal of the mole, suggesting that hCG was responsible for the thyrotoxicosis. Serum hCG concentrations closely paralleled those of free thyroxine, but the correlation was difficult to assess because of carbimazole. Clinical thyrotoxicosis is rare in molar pregnancy. The diagnosis being made in semi-urgent conditions, this raises the question of how to obtain rapid stabilization of the disease before surgery.

  9. Electrolytic conductivity and molar heat capacity of two aqueous solutions of ionic liquids at room-temperature: Measurements and correlations

    Energy Technology Data Exchange (ETDEWEB)

    Lin Peiyin [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Soriano, Allan N. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Manila 1002 (Philippines); Leron, Rhoda B. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Li Menghui, E-mail: mhli@cycu.edu.t [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

    2010-08-15

    As part of our systematic study on physicochemical characterization of ionic liquids, in this work, we report new measurements of electrolytic conductivity and molar heat capacity for aqueous solutions of two 1-ethyl-3-methylimidazolium-based ionic liquids, namely: 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, at normal atmospheric condition and for temperatures up to 353.2 K. The electrolytic conductivity and molar heat capacity were measured by a commercial conductivity meter and a differential scanning calorimeter (DSC), respectively. The estimated experimental uncertainties for the electrolytic conductivity and molar heat capacity measurements were {+-}1% and {+-}2%, respectively. The property data are reported as functions of temperature and composition. A modified empirical equation from another researcher was used to correlate the temperature and composition dependence of the our electrolytic conductivity results. An excess molar heat capacity expression derived using a Redlich-Kister type equation was used to represent the temperature and composition dependence of the measured molar heat capacity and calculated excess molar heat capacity of the solvent systems considered. The correlations applied represent the our measurements satisfactorily as shown by an acceptable overall average deviation of 6.4% and 0.1%, respectively, for electrolytic conductivity and molar heat capacity.

  10. An enthalpy-temperature hybrid method for solving phase change problems and its application to polymer pyrolysis and ignition

    OpenAIRE

    Zhou, Ying-Ying; Fernandez-Pello, Carlos

    2000-01-01

    In this work, an enthalpy-temperature hybrid method is proposed for the numerical solution of generalized phase change problems, and applied to the prediction of polymer pyrolysis and ignition. The basic idea of this method is to treat both enthalpy and temperature as independent variables, and to solve the conservation equations and the constitutive equations (enthalpy-temperature relations) simultaneously. The formula of the enthalpy-temperature relations are not necessary the same for diff...

  11. Behavior of the Enthalpy of Adsorption in Nanoporous Materials Close to Saturation Conditions.

    Science.gov (United States)

    Torres-Knoop, Ariana; Poursaeidesfahani, Ali; Vlugt, Thijs J H; Dubbeldam, David

    2017-07-11

    Many important industrial separation processes based on adsorption operate close to saturation. In this regime, the underlying adsorption processes are mostly driven by entropic forces. At equilibrium, the entropy of adsorption is closely related to the enthalpy of adsorption. Thus, studying the behavior of the enthalpy of adsorption as a function of loading is fundamental to understanding separation processes. Unfortunately, close to saturation, the enthalpy of adsorption is hard to measure experimentally and hard to compute in simulations. In simulations, the enthalpy of adsorption is usually obtained from energy/particle fluctuations in the grand-canonical ensemble, but this methodology is hampered by vanishing insertions/deletions at high loading. To investigate the fundamental behavior of the enthalpy and entropy of adsorption at high loading, we develop a simplistic model of adsorption in a channel and show that at saturation the enthalpy of adsorption diverges to large positive values due to repulsive intermolecular interactions. However, there are many systems that can avoid repulsive intermolecular interactions and hence do not show this drastic increase in enthalpy of adsorption close to saturation. We find that the conventional grand-canonical Monte Carlo method is incapable of determining the enthalpy of adsorption from energy/particle fluctuations at high loading. Here, we show that by using the continuous fractional component Monte Carlo, the enthalpy of adsorption close to saturation conditions can be reliably obtained from the energy/particle fluctuations in the grand-canonical ensemble. The best method to study properties at saturation is the NVT energy (local-) slope methodology.

  12. Split-step eigenvector-following technique for exploring enthalpy landscapes at absolute zero.

    Science.gov (United States)

    Mauro, John C; Loucks, Roger J; Balakrishnan, Jitendra

    2006-03-16

    The mapping of enthalpy landscapes is complicated by the coupling of particle position and volume coordinates. To address this issue, we have developed a new split-step eigenvector-following technique for locating minima and transition points in an enthalpy landscape at absolute zero. Each iteration is split into two steps in order to independently vary system volume and relative atomic coordinates. A separate Lagrange multiplier is used for each eigendirection in order to provide maximum flexibility in determining step sizes. This technique will be useful for mapping the enthalpy landscapes of bulk systems such as supercooled liquids and glasses.

  13. Third molar agenesis and craniofacial morphology.

    Science.gov (United States)

    Sánchez, María José; Vicente, Ascensión; Bravo, Luis Alberto

    2009-05-01

    To test the null hypothesis that agenesis of wisdom teeth is not related with any particular craniofacial morphology. Ninety-seven patients (aged 13-19 years) were selected and divided into three groups: (1) bilateral agenesis of maxillary third molars, (2) bilateral agenesis of mandibular third molars, and (3) control group without agenesis. Presence or absence of third molars was determined using ortopantomographs. Cephalometric analysis was carried out from lateral teleradiographs, which included linear, angular, and proportional measurements. When data obtained were distributed normally it was analyzed by means of single-factor variance analysis and the Scheffé test (P classification in 58.8% of cases. The hypothesis is rejected. Agenesis of the maxillary third molars was related to a reduced mandibular plane angle. Patients with agenesis of the mandibular third molars showed a diminished lower third and a mandibular morphology characteristic of the brachyfacial pattern.

  14. Bilateral maxillary fourth and fifth molars: An unusual radiographic appearance

    Directory of Open Access Journals (Sweden)

    Mukesh Khemchand Asrani

    2016-01-01

    Full Text Available Distomolars are supernumerary teeth present distal to third molars. Although many cases of bilateral fourth molars are reported, very few cases having bilateral fifth molars are described in literature. Here, we present a case having bilateral impacted maxillary fourth and fifth molars with the fifth molar on the left side having an unusually small appearance.

  15. Topiramate Induced Excessive Sialorrhea

    Directory of Open Access Journals (Sweden)

    Ersel Dag

    2015-11-01

    Full Text Available It is well-known that drugs such as clozapine and lithium can cause sialorrhea. On the other hand, topiramate has not been reported to induce sialorrhea. We report a case of a patient aged 26 who was given antiepileptic and antipsychotic drugs due to severe mental retardation and intractable epilepsy and developed excessive sialorrhea complaint after the addition of topiramate for the control of seizures. His complaints continued for 1,5 years and ended after giving up topiramate. We presented this case since it was a rare sialorrhea case induced by topiramate. Clinicians should be aware of the possibility of sialorrhea development which causes serious hygiene and social problems when they want to give topiramate to the patients using multiple drugs.

  16. The influence of premature loss of temporary upper molars on permanent molars.

    Science.gov (United States)

    Cernei, E R; Maxim, Dana Cristiana; Zetu, Irina Nicoleta

    2015-01-01

    Premature loss of primary molars due to dental caries and their complications has been associated with space loss and eruptive difficulties, especially when the loss occurs early. The aim of our study was to determine the impact of premature loss of temporary upper molars upon the longitudinal axis of the first and second upper permanent molar. The study group included 64 patients 6-9 years old with premature loss of primary molars and a control group of 48 patients with intact temporary teeth. It was evaluated the angle between longitudinal axis of first and second upper permanent molars and occlusal plane. The sofware used is Easy Dent 4 Viewer®.The data were analyzed by using the Statistical Package for the Social Sciences (version 20.0; SPSS, Chicago, III). It was observed that premature loss of upper second deciduous molars modifies greater the vertical axis of the permanent molars than the premature loss of first upper primary molar. First upper primary molar loss cause an acceleration eruption of first premolar, which will produce a distal inclintion of the both permanent molars. The use of space maintainers after premature loss of the second upper temporary molar is a last solution in preventing tridimensional lesions in the dental arch and occlusion.

  17. [Correlation between the lower first permanent molar axis and the premature loss of temporary molars].

    Science.gov (United States)

    Petcu, Ana; Maxim, A; Haba, Danisia

    2009-01-01

    The aim of our study was to determine the impact of premature loss of temporary molars upon the longitudinal axis of the first permanent molar. The study sample was formed by 94 orthopanthomografies of child patients with premature loss of lower temporary molars (first or second) after clinical eruption of the first permanent molar. All panoramic radiographs have been realized with the same panoramic unit with 1.4% magnification coefficient and were analyzed using a standardized technique of tracing the images of teeth and bone on matte acetate paper. It was evaluated the angle between longitudinal axis of first permanent lower molar and occlusal plane. It was observed that premature loss of lower second deciduous molar modifies greater the vertical axis of first permanent molar (between 61 degrees and 79 degrees) then premature loss of first lower primary molar. This is perhaps because the loss of space in the case of premature exfoliation of first primary molar is due more to distal drift of canine then mesial drift of molars. The drift to mesial of first permanent molar is more accentuated proportional with the age at which appeared premature loss and so it is loss of leeway space.

  18. Enthalpy of Formation of N 2 H 4 (Hydrazine) Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Feller, David [Department; Bross, David H. [Chemical; Ruscic, Branko [Chemical; Computation

    2017-08-02

    In order to address the accuracy of the long-standing experimental enthalpy of formation of gas-phase hydrazine, fully confirmed in earlier versions of Active Thermochemical Tables (ATcT), the provenance of that value is re-examined in light of new high-end calculations of the Feller-Peterson-Dixon (FPD) variety. An overly optimistic determination of the vaporization enthalpy of hydrazine, which created an unrealistically strong connection between the gas phase thermochemistry and the calorimetric results defining the thermochemistry of liquid hydrazine was identified as the probable culprit. The new enthalpy of formation of gas-phase hydrazine, based on balancing all available knowledge, was determined to be 111.57 ± 0.47 kJ/mol at 0 K (97.41 kJ/mol at 298.15 K). Close agreement was found between the ATcT (even excluding the latest theoretical result) and FPD enthalpies.

  19. Characterization of Adsorption Enthalpy of Novel Water-Stable Zeolites and Metal-Organic Frameworks

    Science.gov (United States)

    Kim, Hyunho; Cho, H. Jeremy; Narayanan, Shankar; Yang, Sungwoo; Furukawa, Hiroyasu; Schiffres, Scott; Li, Xiansen; Zhang, Yue-Biao; Jiang, Juncong; Yaghi, Omar M.; Wang, Evelyn N.

    2016-01-01

    Water adsorption is becoming increasingly important for many applications including thermal energy storage, desalination, and water harvesting. To develop such applications, it is essential to understand both adsorbent-adsorbate and adsorbate-adsorbate interactions, and also the energy required for adsorption/desorption processes of porous material-adsorbate systems, such as zeolites and metal-organic frameworks (MOFs). In this study, we present a technique to characterize the enthalpy of adsorption/desorption of zeolites and MOF-801 with water as an adsorbate by conducting desorption experiments with conventional differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA). With this method, the enthalpies of adsorption of previously uncharacterized adsorbents were estimated as a function of both uptake and temperature. Our characterizations indicate that the adsorption enthalpies of type I zeolites can increase to greater than twice the latent heat whereas adsorption enthalpies of MOF-801 are nearly constant for a wide range of vapor uptakes.

  20. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Science.gov (United States)

    Souki, Bernardo Q.; Cheib, Paula L.; de Brito, Gabriela M.; Pinto, Larissa S. M. C.

    2015-01-01

    Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction. PMID:26321848

  1. Maxillary second molar impaction in the adjacent ectopic third molar: Report of five rare cases

    Directory of Open Access Journals (Sweden)

    Bernardo Q Souki

    2015-01-01

    Full Text Available Maxillary second molar impaction in the adjacent ectopic third molar is a rare condition that practitioners might face in the field of pediatric dentistry and orthodontics. The early diagnosis and extraction of the adjacent ectopic third molar have been advocated, and prior research has reported a high rate of spontaneous eruption following third molar removal. However, some challenges in the daily practice are that the early diagnosis of this type of tooth impaction is difficult with conventional radiographic examination, and sometimes the early surgical removal of the maxillary third molar must be postponed because of the risks of damaging the second molar. The objective of this study is to report a case series of five young patients with maxillary second molar impaction and to discuss the difficulty of early diagnosis with the conventional radiographic examination, and unpredictability of self-correction.

  2. How will mandibular third molar surgery affect mandibular second molar periodontal parameters?

    Science.gov (United States)

    Tabrizi, Reza; Arabion, Hamidreza; Gholami, Mehdi

    2013-07-01

    Several conflicting findings have been published in the previous literature regarding the effects of impacted third molar surgery on the periodontal parameters of the adjacent second molar; some authors have shown improvement of periodontal health distal to the adjacent second molar, whilst others have demonstrated loss of attachment level (AL) and reduction of alveolar bone height. The purpose of this study was to evaluate the changes in periodontal health parameters distal to the adjacent second molar following extraction of an impacted third molar. Out of 50 patients participated in the study, 42 patients completed the study. The mean age of the sample was 20.9 (range, 18-25) years. All teeth were mesioangular impacted mandibular third molars categorized at C1 class based on the Pell and Gregory classification. All surgeries were performed by one surgeon and the same surgeon recorded the pre-operative and post-operative measurements of probing depth (PD) and AL on the distobuccal aspect of the second molars. Data analysis were carried out with the SPSS software (version 19), using the paired-samples t-test and one sample t-test. Surgical extraction of impacted mandibular third molar resulted in a significant increase of PD on the distobuccal aspect of the second molars, whereas AL was decreased significantly after surgery (P molar after extraction of impacted third molar, our study showed a significant increase in PD at the distal aspect of the second molar. Further follow-up on clinical and radiological parameters are required for more profound understanding of the long-term effects of third molar extraction on the periodontal parameters of the adjacent second molar.

  3. Effect of Calcium chloride and Cadmium chloride on the enthalpy of ...

    African Journals Online (AJOL)

    user

    This paper presents the effect of two dissolved inorganic salts, CaCl2 and CdCl2 on the enthalpy of mixing of the binary 1,4 dioxane + water system has been investigated at 303.15 .... liquid mixture taken in the calorimeter to obtain the enthalpy of mixing values in Joules per mole. The performance of the calorimeter and its ...

  4. Enthalpies of dissolution of n-alkanes in a mixture of methanol-formamide

    Science.gov (United States)

    Batov, D. V.; Kustov, A. V.; Antonova, O. A.; Smirnova, N. L.

    2015-06-01

    The enthalpies of dissolution of n-hexane, n-octane, and n-decane are determined thermochemically under standard conditions to describe nonspecific solvation in a mixed solvent of methanol-formamide. Experimental data are matched with the values obtained using model calculations. It is found that the differences between the experimental and calculated enthalpies of dissolution in the region with a high content of formamide could be due to the preferable solvation of n-alkanes by methanol.

  5. Treating Intraradicular Pockets of molars

    Directory of Open Access Journals (Sweden)

    H. Lotfizade

    1987-10-01

    Full Text Available It appears that until bone graft has not achieved 100% success, intraradicular diseases remain controversial and therefore, different treatment plans are suggested for them. Treating intraradicular diseases depend on many factors: maxillary molars are more prone to bone loss and have worse prognosis. To assess prognosis more carefully these factors should be considered: 1 bone loss: its apical depth, local or generalized 2 bone condition: buccal, lingual, mesial and distal aspects 3 tooth mobility: grades 2 and 3 have not good prognosis. Crown root ratio is also important. 4 the angle of divergence of roots: the more the roots are divergent, the better the prognosis would be. 5adjacent teeth health 6tooth position in jaws 7 age and general health of the patients 8 oral hygiene In general, teeth with 2 roots can be treated more effectively than 3 root ones. Maxillary first premolars are exceptions that do not respond to the treatments positively. We should look forward to the future investigations and findings.

  6. Excess molar volumes and viscosities of binary mixtures of 1, 2 ...

    Indian Academy of Sciences (India)

    The Bloomfield and Dewan model has been used to calculate viscosity coefficients and these have also been compared with experimental data for the three mixtures. The results have been discussed in terms of dipole-dipole interactions between 1,2-diethoxyethane and chloroalkanes and their magnitudes decreasing with ...

  7. Excess molar volumes and viscosities of binary mixtures of 1,2 ...

    Indian Academy of Sciences (India)

    Unknown

    dichloromethane (Qualigens, HPLC grade, minimum assay 99⋅8%) and 1,2- diethoxyethane (Lancaster ... by the method of least squares with equal weights assigned to each point. The values of coefficients ai ... where the additivity law in logarithmic form on mole fraction average was taken into account for ideal mixtures.

  8. Fusión de un tercer molar mandibular con un cuarto molar supernumerario Fusion of mandibular third molar with supernumerary fourth molar

    Directory of Open Access Journals (Sweden)

    C. López Carriches

    2008-10-01

    Full Text Available La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia del cordal semiincluido bajo anestesia local. Llevamos a cabo una revisión bibliográfica al respecto.Dental fusion is the union of two tooth buds that normally are separated, while gemination is defined as an attempt by a single tooth bud to divide. The fusion and gemination of molars is uncommon in permanent teeth. We report a clinical case of a right lower third molar fused to a supernumerary fourth molar in a 36-year-old male patient with repeated episodes of inflammation. After the radiologic study, the semi-impacted third molar was extracted under local anesthesia. The literature was reviewed.

  9. Rare occurrence of the left maxillary horizontal third molar impaction ...

    African Journals Online (AJOL)

    Rare occurrence of the left maxillary horizontal third molar impaction, the right maxillary third molar vertical impaction and the left mandibular third molar vertical impaction with inferior alveolar nerve proximity in a 30 year old female: a case report.

  10. Study of kissing molars in Turkish population sample | Yanik ...

    African Journals Online (AJOL)

    Study of kissing molars in Turkish population sample. ... refers to contacting occlusal surfaces of the impacted mandibular second and third molars. ... was to report the incidence of kissing molars (KMs), classification, incorporated pathologies, ...

  11. Cholesterol-induced variations in the volume and enthalpy fluctuations of lipid bilayers.

    Science.gov (United States)

    Halstenberg, S; Heimburg, T; Hianik, T; Kaatze, U; Krivanek, R

    1998-07-01

    The sound velocity and density of suspensions of large unilamellar liposomes from dimyristoylphosphatidylcholine with admixed cholesterol have been measured as a function of temperature around the chain melting temperature of the phospholipid. The cholesterol-to-phospholipid molar ratio xc has been varied over a wide range (0 excess heat capacity of the bilayer system has been derived. Comparison of the compressibilities (and sound velocity numbers) with heat capacity traces display the close correlation between these quantities for bilayer systems. This correlation appears to be very useful as it allows some of the mechanical properties of membrane systems to be calculated from the specific heat capacity data and vice versa.

  12. Episodic Excessive Blinking in Children.

    Science.gov (United States)

    Mali, Yasmin Poustchi; Simon, John W; Chaudhri, Imran; Zobal-Ratner, Jitka; Barry, Gerard P

    2016-01-01

    Many children present with excessive blinking. Categorization, associated conditions, and prognosis are controversial. All children with excessive blinking were reviewed, excluding those with known uveitis, glaucoma, or obvious eyelid abnormalities. Parents were telephoned for follow-up. No ocular pathology was identified in 31 of 34 children with excessive blinking (91%). Parents were able to report a specific cause of blinking in 7 (21%). In 24 of 34 (71%), parents reported complete resolution of excessive blinking. No new ophthalmologic diagnoses were uncovered on follow-up. Episodes of excessive blinking rarely indicate neurologic disorders and frequently resolve spontaneously. Copyright 2016, SLACK Incorporated.

  13. Molar pregnancy and thyroid storm - literature review

    Directory of Open Access Journals (Sweden)

    Filipescu G. A.

    2017-08-01

    Full Text Available Molar pregnancies results from a tainted fertilization process. Trophoblastic thyroidian hyper function is an unusual complication of a molar pregnancy. The degree of thyroid stimulation and the severity of clinical hyperthyroidism is directly proportional to HCG concentration. Human chorionic gonadotrophin is almost identical with TSH, luteinizing hormone (LH and follicle-stimulating hormone, this analogy in the structure will cause cross-reactivity with their receptors. Hyperthyroid status can vary from asymptomatic hyper function to thyroid storm. Dilation and curettage represents the treatment for hyperthyroidism in molar pregnancy. Awareness of this condition is important for diagnosis and treatment.

  14. Unilateral Molar Distalization: A Nonextraction Therapy

    Directory of Open Access Journals (Sweden)

    M. Bhanu Prasad

    2012-01-01

    Full Text Available In the recent years, nonextraction treatment approaches and noncompliance therapies have become more popular in the correction of space discrepancies. One of the conventional approaches for space gaining in the arches without patient compliance is done by using certain extra oral appliances or intraoral appliance. The greatest advantage of certain appliances like fixed functional and molar distalization appliances is that they minimize the dependence on patient cooperation. Molar distalization appliances like pendulum appliance which distalizes the molar rapidly without the need of head gear can be used in patients as a unilateral space gaining procedure due to buccal segment crowding.

  15. Mini-implant-supported Molar Distalization

    Directory of Open Access Journals (Sweden)

    Amit Goyal

    2012-01-01

    Full Text Available Temporary anchorage devices popularly called mini-implants or miniscrews are the latest addition to an orthodontist′s armamentarium. The following case report describes the treatment of a 16-year-old girl with a pleasant profile, moderate crowding and Angle′s Class II molar relationship. Maxillary molar distalization was planned and mini-implants were used to preserve the anterior anchorage. After 13 months of treatment, Class I molar and canine relation was achieved bilaterally and there was no anterior proclination. Thus, mini-implants provide a viable option to the clinician to carry out difficult tooth movements without any side effects.

  16. Treatment of ectopic first permanent molar teeth.

    LENUS (Irish Health Repository)

    Hennessy, Joe

    2012-11-01

    Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. CLINICAL RELEVANCE: This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

  17. A conservative management of iatrogenically damaged distal root of the mandibular second molar

    Directory of Open Access Journals (Sweden)

    Rashmi Bansal

    2017-01-01

    Full Text Available Trauma to the adjacent hard and soft tissue is the most common iatrogenic injury during extraction of the mandibular third molar. As every functional component of the dental arch is of prime importance in contemporary dental practice, the major concern must be in conserving the tooth and its structure as much as possible. The present case discusses the application of this conservative approach for management of iatrogenically damaged distal root of the mandibular second molar during extraction of impacted third molar, in which excessive guttering of alveolar bone and fractured apical third of distal root of 37 was observed radiographically. A conservative and noninvasive approach was successfully achieved to restore the damaged root by the bioactive material. Sealing of the remaining root with mineral trioxide aggregate allowed regeneration of soft and hard tissue around it.

  18. Efficiency of molar distalization with the XBow appliance related to second molar eruption stage.

    Science.gov (United States)

    Flores-Mir, Carlos; McGrath, L M; Heo, G; Major, P W

    2013-12-01

    To quantitatively evaluate on lateral cephalograms horizontal, vertical, and angular changes in the position of the maxillary first molar based on the presence and absence of erupted maxillary second molars when it is distalized with the XBow appliance. In this retrospective study, a total of 102 consecutively treated cases were assessed. Lateral cephalograms were obtained at the start and after completion of active treatment with the XBow appliance. In one group of patients, distal movement of the maxillary first molars was performed before the eruption of maxillary second molars; in the other group of patients, both first and second maxillary molars were simultaneously moved distally. All cephalograms were superimposed on palatal plane using the method of best-fit. In order to compare the mean horizontal, vertical, and angular changes in molar position between the treatment groups and gender, a multivariate analysis of covariance (MANCOVA) was performed with the pre-treatment class II severity used as a covariate. Regression analysis was also performed to further explore any possible relationships between the predictor variables and the quantity and quality of distalization. A MANCOVA revealed that the eruption stage of the maxillary second molar did not have a significant effect on the change in position of the maxillary first molar after treatment with a XBow appliance. When distalizing maxillary first molars with a XBow appliance, there is no difference in the amount of distalization in patients with erupted and unerupted maxillary second molars.

  19. A Molar Pregnancy within the Fallopian Tube

    Directory of Open Access Journals (Sweden)

    Laura Allen

    2016-01-01

    Full Text Available Background. Discussion of the incidence of molar pregnancy and ectopic pregnancy. Role of salpingostomy and special considerations for postoperative care. Case. The patient is a 29-year-old G7P4 who presented with vaginal bleeding in the first trimester and was initially thought to have a spontaneous abortion. Ultrasound was performed due to ongoing symptoms and an adnexal mass was noted. She underwent uncomplicated salpingostomy and was later found to have a partial molar ectopic pregnancy. Conclusion. This case illustrates the rare occurrence of a molar ectopic pregnancy. There was no indication of molar pregnancy preoperatively and this case highlights the importance of submitting and reviewing pathological specimens.

  20. IMPLICATIONS OF PREMATURE LOSS OF PRIMARY MOLARS

    Directory of Open Access Journals (Sweden)

    Ana PETCU

    2016-06-01

    Full Text Available The pathology of premature loss of temporary molars is a complex issue with profound impact on dental and facial harmony, urging clinician`s interest for an optimal therapeutic approach. Identification of the predisposing factors, in full agreement with the anatomical particularities of the temporary teeth, corroborated with the incidence of premature loss of molars is a main condition for an optimal therapeutic management of these patients.

  1. Efficiency of a pendulum appliance for molar distalization related to second and third molar eruption stage.

    Science.gov (United States)

    Kinzinger, Gero S M; Fritz, Ulrike B; Sander, Franz-Günter; Diedrich, Peter R

    2004-01-01

    A modified pendulum appliance, including a distal screw and special preactivated pendulum springs (built-in straightening activation and toe-in bending), was used for bilateral maxillary molar distalization in 36 adolescent patients in various stages of the molar dentition. The patients were divided into 3 groups (PG 1-3) according to the stage of eruption of their second and third molars. In PG 1 (18 patients), eruption of the second molars had either not yet taken place or was not complete. In PG 2 (15 patients), the second molars had already developed as far as the occlusal plane, with the third molars at the budding stage. In PG 3 (3 patients), germectomy of the wisdom teeth had been carried out, and the first and second molars on both sides had completely erupted. Analysis of cephalograms to identify any changes in the sagittal plane showed that, in the direction of distalization, a tooth bud acts on the mesial neighboring tooth like a fulcrum, and that tipping of the first molars in patients in whom the second molar was still at the budding stage was thus greater. In patients whose second molars had erupted completely, the degree of tipping was greater again when a third molar bud was located in the direction of movement. After previously completed germectomy of the wisdom teeth, almost exclusively bodily distalization of both molars is possible, even without bands being applied to the second molars. However, if the first and second molars are distalized simultaneously with a pendulum appliance, the duration of therapy will be longer, greater forces will have to be applied, and more anchorage will be lost. Statistical analysis of the results of dental-angular measurements showed significant differences in the degree of molar tipping and reciprocal incisor protrusion. The degree of distal tipping of first molars was less in patients with erupted second molars (PG 2 and PG 3) than in those whose second molars were not yet erupted (PG 1). For instance, the

  2. Economic and health implications of routine CBCT examination before surgical removal of the mandibular third molar in the Danish population

    DEFF Research Database (Denmark)

    Petersen, L B; Rose Olsen, Kim; Matzen, L H

    2015-01-01

    OBJECTIVES: This epidemiological study aimed to analyse economical and societal consequences in Denmark if CBCT is used routinely as a diagnostic method before removal of the mandibular third molar. Furthermore, the aim was to calculate the excess cancer incidence from this practice. METHODS: 17 ...

  3. Case studies for utilizing groundwater-source and low-enthalpy geothermal resources in Korea

    Science.gov (United States)

    Kim, K.-H.; Shin, J.; Lee, K.-K.; Lee, T. J.

    2012-04-01

    As one of the top 10 oil-consuming countries in the world, Korea recently has had a great interest in extending the ways to utilize renewable energy. In this regard, geothermal energy resource is attracting more concerns from both of the government and the research field. Korea has neither active volcanic sites nor areas with abnormally higher heat flow. In spite of these natural conditions, many efforts have been exerted to utilize geothermal energy. Here, we introduce two case studies of using groundwater-source geothermal energy with relatively low-enthalpy: One is a riverbank filtration facility, which has been using some of its riverbank filtrate water for the indoor air-conditioning. The other is the first EGS plant planning site, where a few fault-related artesian wells reaching 70C were discovered lately. Numerical simulations to predict the temperature evolution of the two sites, which is dominated by several hydrogeologic factors, were carried out and compared. Simulation of temperature profile of riverbank filtrate water using HydroGeoSphere shows that the primary factor in determining filtrate water temperature is the pumping rate. It also shows that maintaining the facility operation with present pumping rate for the next 30 years will not cause any significant change of water temperature. However, following the new plan of the facility to install additional 37 wells with 6 times higher pumping rate than the current rate might cause about 2C decrease in filtrate water temperature in 10 years after the extension. Simulation for the temperature evolution in a faulted geothermal reservoir in EGS planning site under the supposed injection-extraction operating conditions were carried out using TOUGH2. A MINC model including a hydraulic discontinuity, which reflected the analysis from several geophysical explorations, was generated. Temperature distribution calculated from the simulation shows a rise of relatively hot geothermal water along the fault plane

  4. Predicting pathology in impacted mandibular third molars

    Directory of Open Access Journals (Sweden)

    Aveek Mukherji

    2017-01-01

    Full Text Available Introduction: The rising incidence of the impacted mandibular third molars and their association with pathologies is now considered a public health problem. Aims and Objectives: The objective of this study was to assess the position of impacted mandibular third molars that are prone to developing pathologies and to determine the frequency and type of pathological conditions associated with these impacted teeth to facilitate planning for their prophylactic removal. Materials and Methods: Consecutive panoramic radiographs and clinical examination of 300 patients with impacted mandibular third molars were collected. They were segregated according to Pell and Gregory’s classification, Winter’s classification, and according to their state of eruption. These were correlated with associated pathologies based on clinical and radiological criteria. Statistical Analysis Used: Descriptive statistics included computation of percentages, mean, and standard deviations. The statistical test applied for the analysis was Pearson’s Chi-square test (χ2. For this test, confidence interval and P value were set at 93% and ≤0.03, respectively. Results: The pathology most commonly associated with impacted third molars was pericoronitis, which had the highest frequency of occurrence in partially erupted, distoangular, and IA positioned (as per Pell and Gregory classification impacted teeth. Impacted mandibular third molars, which were in IA position, placed mesially, and partially erupted, were prone to develop pathologies such as dental caries and periodontitis. Conclusion: The clinical and radiographical features of impacted third molar may be correlated to the development of their pathological complications. The partially impacted mandibular third molars with mesioangularly aligned in IA position have the highest potential to cause pathological complications.

  5. Enthalpies of solution of methylcalix[4]resorcinarene in non-aqueous solvents as a function of concentration and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Riveros, Diana C. [Laboratorio de Termodinamica de Soluciones, Departamento de Quimica, Facultad de Ciencias, Universidad de los Andes, Bogota D.C. (Colombia); Martinez, Fleming [Grupo de Investigaciones Farmaceutico-Fisicoquimicas, Departamento de Farmacia, Facultad de Ciencias, Universidad Nacional de Colombia, Bogota D.C. (Colombia); Vargas, Edgar F., E-mail: edvargas@uniandes.edu.co [Laboratorio de Termodinamica de Soluciones, Departamento de Quimica, Facultad de Ciencias, Universidad de los Andes, Bogota D.C. (Colombia)

    2012-11-20

    Highlights: Black-Right-Pointing-Pointer The solution enthalpies of methylcalix[4]resorcinarene in alcohols have been measured. Black-Right-Pointing-Pointer The solution enthalpies of methylcalix[4]resorcinarene in alcohols are endothermic. Black-Right-Pointing-Pointer Enthalpies of transference are interpreted in terms of proton donor capacity of alcohols. - Abstract: Enthalpies of solution of 2,8,14,20-tetramethyl-4,6,10,12,16,18,22,24-octahydroxyresorci[4]arene in methanol, ethanol and propanol as a function of molal concentration at (288.15, 298.15 and 308.15) K were measured calorimetrically. The enthalpies of solvation were estimated. Using propanol as the referent solvent, transfer properties to other alcohols were also calculated. In addition, temperature dependence of the enthalpy of solution at infinite dilution was also obtained. The data were interpreted in terms of solute-solvent interactions.

  6. Measuring Excess Noise in SDL's

    Science.gov (United States)

    Katzberg, S. J.; Kowitz, H. R.; Rowland, C. W.; Shull, T. A.; Ruggles, S. L.; Matthews, L. F.

    1983-01-01

    New instrument gives quantitive information on "excess noise" in semiconductor-diode laser (SDL's). By proper selection of detector, instrument tests any SDL from visible wavelengths through thermal infrared. Lasers determine excess noise in SKL source by measuring photocurrent generated in photodetector exposed first to reference laser then to SKL under test.

  7. From a network of computed reaction enthalpies to atom-based thermochemistry (NEAT).

    Science.gov (United States)

    Császár, Attila G; Furtenbacher, Tibor

    2010-04-26

    A simple and fast, weighted, linear least-squares refinement protocol and code is presented for inverting the information contained in a network of quantum chemically computed 0 K reaction enthalpies. This inversion yields internally consistent 0 K enthalpies of formation for the species of the network. The refinement takes advantage of the fact that the accuracy of computed enthalpies depends strongly on the quantum-chemical protocol employed for their determination. Different protocols suffer from different sources of error; thus, the reaction enthalpies computed by them have "random" residual errors. Since it is much more natural for quantum-chemical energy and enthalpy results, including reaction enthalpies, to be based on the electronic ground states of the atoms and not on the historically preferred elemental states, and since these two possible protocols can be converted into each other straightforwardly, it is proposed that first-principles thermochemistry should employ the ground electronic states of atoms. In this scheme, called atom-based thermochemistry (AT), the enthalpy of formation of a gaseous compound corresponds simply to the total atomization energy of the species; it is always positive, and it reflects the bonding strength within the molecule. The inversion protocol developed and based on AT is termed NEAT, which represents the fact that the protocol proceeds from a network of computed reaction enthalpies toward atom-based thermochemistry, most directly to atom-based enthalpies of formation. After assembling a database that consisted of 361 ab initio reactions and reaction enthalpies involving 188 species, collected from 31 literature sources, the following dependable 0 K atom-based enthalpies of formation, Delta(f)${H{{{\\rm AT}\\hfill \\atop 0\\hfill}}}$, all in kJ mol(-1), have been obtained by means of NEAT: H(2)=432.07(0), CH=334.61(15), NH=327.69(25), OH=425.93(21), HF=566.13(31), CO=1072.08(28), O(2)=493.51(34), CH(2)=752.40(21), H(2)O

  8. Measurement of the aerothermodynamic state in a high enthalpy plasma wind-tunnel flow

    Science.gov (United States)

    Hermann, Tobias; Löhle, Stefan; Zander, Fabian; Fasoulas, Stefanos

    2017-11-01

    This paper presents spatially resolved measurements of absolute particle densities of N2, N2+, N, O, N+ , O+ , e- and excitation temperatures of electronic, rotational and vibrational modes of an air plasma free stream. All results are based on optical emission spectroscopy data. The measured parameters are combined to determine the local mass-specific enthalpy of the free stream. The analysis of the radiative transport, relative and absolute intensities, and spectral shape is used to determine various thermochemical parameters. The model uncertainty of each analysis method is assessed. The plasma flow is shown to be close to equilibrium. The strongest deviations from equilibrium occur for N, N+ and N2+ number densities in the free stream. Additional measurements of the local mass-specific enthalpy are conducted using a mass injection probe as well as a heat flux and total pressure probe. The agreement between all methods of enthalpy determination is good.

  9. Enthalpy-Based Screening of Focused Combinatorial Libraries for the Identification of Potent and Selective Ligands.

    Science.gov (United States)

    Baggio, Carlo; Udompholkul, Parima; Barile, Elisa; Pellecchia, Maurizio

    2017-12-15

    In modern drug discovery, the ability of biophysical methods, including nuclear magnetic resonance spectroscopy or surface plasmon resonance, to detect and characterize ligand-protein interactions accurately and unambiguously makes these approaches preferred versus conventional biochemical high-throughput screening of large collections of compounds. Nonetheless, ligand screening strategies that address simultaneously potency and selectivity have not yet been fully developed. In this work, we propose a novel method for screening large collections of combinatorial libraries using enthalpy measurements as a primary screening technique. We demonstrate that selecting binders that are driven by enthalpy (ΔH) results in agents that are not only potent but also more selective for a given target. This general and novel approach, we termed ΔH screening of fPOS (enthalpy screening of focused positional scanning library), combines the principles of focused combinatorial chemistry with rapid calorimetry measurements to efficiently identify potent and selective inhibitors.

  10. A Reaction Method for Estimating Gibbs Energy and Enthalpy of Formation of Complex Minerals

    Science.gov (United States)

    Li, Ruibing; Zhang, Tingan; Liu, Yan; Kuang, Shibo

    2017-04-01

    New and updated thermodynamic data for simple binary compounds are readily available from both experimental measurements and theoretical calculations. Based on these available data, an approach is proposed to predict Gibbs energies and enthalpies of formation for complex minerals of metallurgical, chemical, and other industrial importance. The approach assumes that complex minerals are formed from binary composite oxides, which in turn, are formed from individual pure oxides. The validity of this approach is examined by comparing the calculated values of Gibbs energies and enthalpies against the experimentally measured ones reported in literature. The results show that for typical complex minerals with available experimental data, the calculated results exhibit an average residual of 0.51 pct for Gibbs energies and 0.52 pct for enthalpies, compared to the experimental results. This new approach thus correlates well with experimental approaches and can be applied to most of the complex minerals.

  11. Ketac Molar Versus Dyract Class II restorations in primary molars: twelve month clinical results.

    Science.gov (United States)

    Marks, L A; van Amerongen, W E; Borgmeijer, P J; Groen, H J; Martens, L C

    2000-01-01

    The aim of the present clinical study was an in vivo evaluation of an improved conventional glass ionomer cement Ketac Molar (ESPE), compared to a polyacid modified composite resin, Dyract (Dentsply/De Trey), used in primary molars. Fifty-three Ketac Molar and fifty-two Dyract restorations were placed in box-only preparations in primary molars. The application time for the chemically cured Ketac Molar, was longer compared to the light-cured Dyract. In comparing the materials, no differences were found, comparing both materials regarding secondary caries, marginal adaptation, wear and fracture toughness. One case of recurrent caries adjacent to a Ketac Molar restoration and two cases in the Dyract group were reported. Two Ketac Molar restorations and one Dyract showed bulk fracture at the time of evaluation. At the twelve-month evaluation, no difference between the investigated materials was registered, which indicates that Ketac Molar can be used as a proximal restoration in the primary dentition. It should be emphasized, however, that one-year data should not be extrapolated to indicate the long-term success of restorations.

  12. Computational Investigation of Enthalpy-Entropy Compensation in Complexation of Glycoconjugated Bile Salts with β-Cyclodextrin and Analogs

    DEFF Research Database (Denmark)

    Tidemand, Kasper Damgaard; Schonbeck, Christian; Holm, Rene

    2014-01-01

    of water molecules in the cavity increased with the DS. Release of water from the cavity resulted in a positive enthalpy change, which correlates qualitatively with the experimentally determined increase in complexation enthalpy and contributes to the enthalpy-entropy compensation. The positive change...... in complexation entropy with DS was not able to compensate for this unfavorable change in enthalpy induced by the HP substituents, resulting in a destabilizing effect. This was found to originate from fixation of the HP substituents and decreased free rotation of the bile salts within the CD cavities....

  13. Enthalpy analysis and Heat Exchanger Sizing of an Air-cooled Proton Exchange Membrane Fuel Cell System

    DEFF Research Database (Denmark)

    Gao, Xin; Berning, Torsten; Kær, Søren Knudsen

    the warmer exhaust air is used to pre-heat and also humidify the incoming colder and dryer air stream using an enthalpy wheel. It is important to thermodynamically understand such a fuel cell system, and in this work the enthalpy streams and the humidity stream are followed throughout the fuel cell system...... simulations have been carried out to better understand the distribution of the reactant air over the fuel cell stack and the resulting temperature distribution across the stack. These results suggest that the humidifying function of the current enthalpy wheel is negligible and a smaller enthalpy wheel...

  14. Comparative evaluation of molar distalization therapy with erupted second molar: Segmented versus Quad Pendulum appliance.

    Science.gov (United States)

    Caprioglio, Alberto; Cozzani, Mauro; Fontana, Mattia

    2014-01-01

    There are controversial opinions about the effect of erupted second molars on distalization of the first molars. Most of the distalizing devices are anchored on the first molars, without including second molars; so, differences between sequentially distalize maxillary molars (second molar followed by the first molar) or distalize second and first molars together are not clear. The aim of the study was to compare sequential versus simultaneous molar distalization therapy with erupted second molar using two different modified Pendulum appliances followed by fixed appliances. The treatment sample consisted of 35 class II malocclusion subjects, divided in two groups: group 1 consisted of 24 patients (13 males and 11 females) with a mean pre-treatment age of 12.9 years, treated with the Segmented Pendulum (SP) and fixed appliances; group 2 consisted of 11 patients (6 males and 5 females) with a mean pre-treatment age of 13.2 years, treated with the Quad Pendulum (QP) and fixed appliances. Lateral cephalograms were obtained before treatment (T1), at the end of distalization (T2), and at the end of orthodontic fixed appliance therapy (T3). A Student t test was used to identify significant between-group differences between T1 to T2, T2 to T3, and T1 to T3. QP and SP were equally effective in distalizing maxillary molars (3.5 and 4 mm, respectively) between T1 and T2; however, the maxillary first molar showed less distal tipping (4.6° vs. 9.6°) and more extrusion (1.1 vs. 0.2 mm) in the QP group than in the SP group, as well as the vertical facial dimension, which increased more in the QP group (1.2°) than in the SP group (0.7°). At T3, the QP group maintained greater increase in lower anterior facial height and molar extrusion and decrease in overbite than the SP group. Quad Pendulum seems to have greater increase in vertical dimension and molar extrusion than the Segmented Pendulum.

  15. Effect of the initial stage of annealing on modeling of enthalpy relaxation in a hyperquenched glass

    DEFF Research Database (Denmark)

    Zhang, Yanfei; Guo, Xiaoju; Yue, Yuanzheng

    2013-01-01

    One of the major challenges in glass relaxation study is to establish a universal model describing the enthalpy relaxation in both the hyperquenched glass (HQG) (i.e., far from equilibrium) and the partially annealed hyperquenched glass(AHQG). In particular, the detailed features of the enthalpy...... proposed composite relaxation function [L. Hornboell, et al., Chem. Phys. Lett. 1-3 (2010) 37] is a reasonable approach for describing those features. In addition, our modeling results imply that the structural heterogeneity plays a crucial role in relaxation of HQG....

  16. Covalent and ionic nature of the dative bond and account of accurate ammonia borane binding enthalpies.

    Science.gov (United States)

    Plumley, Joshua A; Evanseck, Jeffrey D

    2007-12-27

    The inherent difficulty in modeling the energetic character of the B-N dative bond has been investigated utilizing density functional theory and ab initio methods. The underlying influence of basis set size and functions, thermal corrections, and basis set superposition error (BSSE) on the predicted binding enthalpy of ammonia borane (H3B-NH3) and four methyl-substituted ammonia trimethylboranes ((CH3)3B-N(CH3)nH3-n; n = 0-3) has been evaluated and compared with experiment. HF, B3LYP, MPW1K, MP2, QCISD, and QCISD(T) have been utilized with a wide range of Pople and correlation-consistent basis sets, totaling 336 levels of theory. MPW1K, B3LYP, and HF result in less BSSE and converge to binding enthalpies with fewer basis functions than post-SCF techniques; however, the methods fail to model experimental binding enthalpies and trends accurately, producing mean absolute deviations (MADs) of 5.1, 10.8, and 16.3 kcal/mol, respectively. Despite slow convergence, MP2, QCISD, and QCISD(T) using the 6-311++G(3df,2p) basis set reproduce the experimental binding enthalpy trend and result in lower MADs of 2.2, 2.6, and 0.5 kcal/mol, respectively, when corrected for BSSE and a residual convergence error of ca. 1.3-1.6 kcal/mol. Accuracy of the predicted binding enthalpy is linked to correct determination of the bond's dative character given by charge-transfer frustration, QCTF = -(Delta QN + Delta QB). Frustration gauges the incompleteness of charge transfer between the donor and the acceptor. The binding enthalpy across ammonia borane and methylated complexes is correlated to its dative character (R2 = 0.91), where a more dative bond (less charge-transfer frustration) results in a weaker binding enthalpy. However, a balance of electronic and steric factors must be considered to explain trends in experimentally reported binding enthalpies. Dative bond descriptors, such as bond ionicity and covalency are important in the accurate characterization of the dative bond. The B

  17. An Implicit Mixed Enthalpy-Temperature Method For Phase-Change Problems

    DEFF Research Database (Denmark)

    Krabbenhoft, Kristian; Damkilde, Lars; Nazem, M.

    2007-01-01

    Abstract A finite element procedure for phase-change problems is presented. Enthalpy and temperature are interpolated separately and subsequently linked via the appropriate relation in the nodes of the mesh during the solution phase. A novel technique is here used where, depending...... on the characteristics of the problem, either temperature or enthalpy may be considered as primary variable. The resulting algorithm is both efficient and robust and is further easy to implement and generalize to arbitrary finite elements. The capabilities of the method are illustrated by the solution both isothermal...... and nonisothermal phase-change problems....

  18. Standard Practice for Measuring Plasma Arc Gas Enthalpy by Energy Balance

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This practice covers the measurement of total gas enthalpy of an electric-arc-heated gas stream by means of an overall system energy balance. This is sometimes referred to as a bulk enthalpy and represents an average energy content of the test stream which may differ from local values in the test stream. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  19. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, January-March 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1986-04-30

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the seventh quarter, preliminary enthalpy measurements for the 5/6:1/6 m-cresol/tetralin binary mixture have been completed and are included in Appendix A at the end of this report. Vapor liquid equilibria VLE measurements for the m-cresol/tetralin system have been completed for four isotherms; 250, 275, 300, 325/sup 0/C. These results and a summary of progress to date for the VLE apparatus are in the appendix at the end of this report. 10 refs., 15 figs., 6 tabs.

  20. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, July-September 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-10-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the fifth quarter, preliminary enthalpy measurements for the 50/50 mole percent m-cresol/tetralin binary mixture have almost been completed and figure illustrating the preliminary results have been included in this report. Vapor liquid equilibria measurements for the m-cresol/quinoline system have been completed for four isotherms. Results have been included in this report. 6 refs., 13 figs., 4 tabs.

  1. Fabrication and Evaluation of a Noncompliant Molar Distalizing Appliance: Bonded Molar Distalizer

    Directory of Open Access Journals (Sweden)

    S. Arab

    2011-09-01

    Full Text Available Objective: Attempts to treat class II malocclusions without extraction in non-compliant patients have led to utilization of intraoral molar distalizing appliances. The purpose of this study was to investigate dental and skeletal effects of Bonded Molar Distalizer (BMD which is a simple molar distalizing appliance.Materials and Methods: Sixteen patients (12 girls, four boys with bilateral half-cusp class II molar relationship, erupted permanent second molars and normal or vertical growth pattern were selected for bilateral distalization of maxillary molars via BMD. Thescrews were activated every other day, alternately. Lateral cephalograms and study models were obtained before treatment and after 11 weeks activation of the appliance.Results: Significant amounts of molar distalization, molar distal tipping and anchorage loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12 mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH decreased 1.28±1.36 mm.Conclusion: BMD is appropriate for distalizing maxillary molars, especially in patients with critical LAFH, although significant amounts of anchorage loss occur using this appliance.

  2. Fusión de un tercer molar mandibular con un cuarto molar supernumerario Fusion of mandibular third molar with supernumerary fourth molar

    OpenAIRE

    C. López Carriches; I. Leco Berrocal; R. Baca Pérez-Bryan

    2008-01-01

    La fusión dental es la unión de dos gérmenes dentales normalmente separados, mientras que la geminación se define como el intento de división de un único germen dental. La fusión y geminación de molares es poco frecuente en la dentición permanente. Describimos un caso clínico de un tercer molar inferior derecho fusionado a un cuarto molar supernumerario en un paciente varón de 36 años que ha presentado repetidos episodios de pericoronaritis. Tras el estudio radiológico se realiza la exodoncia...

  3. Does Excessive Pronation Cause Pain?

    DEFF Research Database (Denmark)

    Olesen, Christian Gammelgaard; Nielsen, RG; Rathleff, M

    Excessive pronation could be an inborn abnormality or an acquired foot disorder caused by overuse, inadequate supported shoes or inadequate foot training. When the muscles and ligaments of the foot are insufficient it can cause an excessive pronation of the foot. The current treatment consist...... of antipronation shoes or insoles, which latest was studied by Kulce DG., et al (2007). So far there have been no randomized controlled studies showing methods that can measure the effect of treatments with insoles. Some of the excessive pronation patients recieve antipronation training often if the patient...

  4. Enthalpy-based equation of state for highly porous materials employing modified soft sphere fluid model

    Science.gov (United States)

    Nayak, Bishnupriya; Menon, S. V. G.

    2018-01-01

    Enthalpy-based equation of state based on a modified soft sphere model for the fluid phase, which includes vaporization and ionization effects, is formulated for highly porous materials. Earlier developments and applications of enthalpy-based approach had not accounted for the fact that shocked states of materials with high porosity (e.g., porosity more than two for Cu) are in the expanded fluid region. We supplement the well known soft sphere model with a generalized Lennard-Jones formula for the zero temperature isotherm, with parameters determined from cohesive energy, specific volume and bulk modulus of the solid at normal condition. Specific heats at constant pressure, ionic and electronic enthalpy parameters and thermal excitation effects are calculated using the modified approach and used in the enthalpy-based equation of state. We also incorporate energy loss from the shock due to expansion of shocked material in calculating porous Hugoniot. Results obtained for Cu, even up to initial porosities ten, show good agreement with experimental data.

  5. Fractured Anhydrite as a Geothermal Source in a Low Enthalpy Context (Southern Permian Basin, Netherlands)

    NARCIS (Netherlands)

    Daniilidis, Alexandros; Herber, Marinus

    2015-01-01

    Increased heat flow associated with the presence of salt domes could be beneficial for geothermal energy applications in a low enthalpy nvironment. Anhydrite layers within such salt domes could be a potential geothermal target. These layers are known to undergo brittle deformation, which in turn can

  6. Enthalpies of mixing in binary liquid alloys of lutetium with 3d metals

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Michael; Berezutski, Vadim [National Academy of Sciences, Kyiv (Ukraine). I. Frantsevich Institute for Problems of Materials Science; Usenko, Natalia; Kotova, Natalia [Taras Shevchenko National Univ., Kyiv (Ukraine). Dept. of Chemistry

    2017-01-15

    The enthalpies of mixing in binary liquid alloys of lutetium with chromium, cobalt, nickel and copper were determined at 1 773 - 1 947 K by isoperibolic calorimetry. The enthalpies of mixing in the Lu-Cr melts (measured up to 40 at.% Cr) demonstrate endothermic effects (ΔH = 6.88 ± 0.66 kJ . mol{sup -1} at x{sub Lu} = 0.60), whereas significant exothermic enthalpies of mixing have been established within a wide composition region for the Co-Lu, Ni-Lu and Cu-Lu liquid alloys. Minimum values of the integral enthalpy of mixing are as follows: ΔH{sub min} = -23.57 ± 1.41 kJ . mol{sup -1} at x{sub Lu} = 0.38 for the Co-Lu system; ΔH{sub min} = -48.65 ± 2.83 kJ . mol{sup -1} at x{sub Lu} = 0.40 for the Ni-Lu system; ΔH{sub min} = -24.63 ± 1.52 kJ . mol{sup -1} at x{sub Lu} = 0.37 for the Cu-Lu system.

  7. An evaluation of interferences in heat production from low enthalpy geothermal doublets systems

    NARCIS (Netherlands)

    Willems, C.J.L.; Maghami Nick, Hamidreza M.; Weltje, G.J.; Bruhn, D.F.

    2017-01-01

    Required distance between doublet systems in low enthalpy geothermal heat exploitation is often not fully elucidated. The required distance aims to prevent negative interference influencing the utilisation efficiency of doublet systems. Currently production licence areas are often issued based on

  8. Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

    Energy Technology Data Exchange (ETDEWEB)

    Agraval, Pavel; Turchanin, Mikhail [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Dreval, Liya [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Materials Science International Services GmbH (MSI), Stuttgart (Germany)

    2016-12-15

    In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x{sub Cu}/x{sub Fe} = 3/1, 1/1 at x{sub Hf} = 0-0.47 and along the section x{sub Cu}/x{sub Fe} = 1/3 at x{sub Hf} = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ{sub mix} anti H{sub Hf}{sup ∞}, are (-122 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 3/1), (-106 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/1), and (-105 ± 2) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.

  9. Coupling geophysical investigation with hydrothermal modeling to constrain the enthalpy classification of a potential geothermal resource.

    Science.gov (United States)

    White, Jeremy T.; Karakhanian, Arkadi; Connor, Chuck; Connor, Laura; Hughes, Joseph D.; Malservisi, Rocco; Wetmore, Paul

    2015-01-01

    An appreciable challenge in volcanology and geothermal resource development is to understand the relationships between volcanic systems and low-enthalpy geothermal resources. The enthalpy of an undeveloped geothermal resource in the Karckar region of Armenia is investigated by coupling geophysical and hydrothermal modeling. The results of 3-dimensional inversion of gravity data provide key inputs into a hydrothermal circulation model of the system and associated hot springs, which is used to evaluate possible geothermal system configurations. Hydraulic and thermal properties are specified using maximum a priori estimates. Limited constraints provided by temperature data collected from an existing down-gradient borehole indicate that the geothermal system can most likely be classified as low-enthalpy and liquid dominated. We find the heat source for the system is likely cooling quartz monzonite intrusions in the shallow subsurface and that meteoric recharge in the pull-apart basin circulates to depth, rises along basin-bounding faults and discharges at the hot springs. While other combinations of subsurface properties and geothermal system configurations may fit the temperature distribution equally well, we demonstrate that the low-enthalpy system is reasonably explained based largely on interpretation of surface geophysical data and relatively simple models.

  10. The Relationship between Lattice Enthalpy and Melting Point in Magnesium and Aluminium Oxides. Science Notes

    Science.gov (United States)

    Talbot, Christopher; Yap, Lydia

    2013-01-01

    This "Science Note" presents a study by Christopher Talbot and Lydia Yap, who teach IB Chemistry at Anglo-Chinese School (Independent), Republic of Singapore, to pre-university students. Pre-university students may postulate the correlation between the magnitude of the lattice enthalpy compound and its melting point, since both…

  11. Does Excessive Pronation Cause Pain?

    DEFF Research Database (Denmark)

    Mølgaard, Carsten Møller; Olesen Gammelgaard, Christian; Nielsen, R. G.

    2008-01-01

    Excessive pronation could be an inborn abnormality or an acquired foot disorder caused by overuse, inadequate supported shoes or inadequate foot training. When the muscles and ligaments of the foot are insufficient it can cause an excessive pronation of the foot. The current treatment consist of ...... pronation patients recieve antipronation training often if the patient is in pain but wanted to investigate if it was possible to measure a change in foot posture after af given treatment....

  12. Evaluación del distalador molar Belussi Evaluation of Belussi's molar distalizer

    Directory of Open Access Journals (Sweden)

    Samer Abdel Nour Khoury

    2008-12-01

    Full Text Available La distalización de los molares superiores en mesogresión es una alternativa de tratamiento muy utilizado en nuestros días. Se conocen muchos métodos de distalización molar, estos han evolucionado notablemente y siguen siendo eficaces en el tratamiento. El objetivo de esta investigación fue evaluar los cambios dentales producidos por el distalador molar Belussi. El aparato fue empleado en 11 pacientes con una edad promedio de 12 años, distoclusión de molares causada por mesogresión, y con tipo facial favorable. A cada uno se le confeccionaron modelos de estudio y se le realizaron fotografías, radiografías panorámicas y telerradiografías laterales de cráneo, antes y después del tratamiento, para analizar las variables objeto de estudio. El aparato se mantuvo en boca hasta lograr un sobretratamiento de la relación molar. Finalmente, se obtuvo una distalización molar de 4,45 mm acompañada de una inclinación de 5,55°, con una pérdida mínima de anclaje temporal.The distalization of the superior molars in mesial migration is a useful alternative treatment nowadays. Many methods of molar distalization are known. They have significantly evolved and they are still effective in the treatment. The objective of this investigation was to evaluate the dental changes produced by Belussi Molar Distalizer. The appliance was used in 11 patients with an average of 12 years-old, distoocclusion of molars caused by mesial migration and with a favorable facial type. Study models were made for each one of them and pictures, panoramic x-rays and lateral X-rays of the skull were taken, before and after the treatment, to analyze the variables object of study. The appliance was kept in the mouth until achieving an overtreatment of the molar relation. Finally, a molar distalization of 4.45 mm accompanied with an inclination of 5.55° was obtained, with a minimum loss of temporary anchorage.

  13. Molar Tissue in Spleen: A Case Report

    Directory of Open Access Journals (Sweden)

    Maral Mokhtari

    2016-04-01

    Full Text Available An invasive mole is a rare form of gestational trophoblastic disease in which the molar tissue invades into the deep myometrium, cervical stroma, blood vessels or extrauterine sites. This report is of an invasive mole of spleen that has originated from an ectopic pregnancy, which was primarily though to be a choriocarcinoma.

  14. Taurodontism in deciduous Molars - A Case Report.

    Science.gov (United States)

    Bhat, S S; Sargod, S; Mohammed, S V

    2004-01-01

    Taurodontism has a very low incidence in deciduous dentition and very few cases are reported in the literature, it stands a challenge when it requires pulp therapy. This case report presents a case of Taurodontism in deciduous molars of a five year old male child which required pulp therapy. A clinical and radiographic follow up of the patient is discussed.

  15. Molar extinction coefficients of some fatty acids

    DEFF Research Database (Denmark)

    Sandhu, G.K.; Singh, K.; Lark, B.S.

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good agreement...

  16. ERUPTION DISTURBANCES OF PERMANENT MOLARS - A REVIEW

    NARCIS (Netherlands)

    RAGHOEBAR, GM; BOERING, G; VISSINK, A; STEGENGA, B

    Eruption disturbances of permanent molars may become clinically and radiographically manifest as impaction, primary retention or secondary retention. This may result in clinical problems such as malocclusion and loss of neighboring teeth due to caries and periodontal disease. Which of these

  17. Distalización de molares

    Directory of Open Access Journals (Sweden)

    Ana María García Jiménez

    2016-01-01

    Full Text Available La distoclusión es una anomalía que alcanza a más de la mitad de los pacientes ortodóncicos, entre sus causas se encuentra la mesogresión de molares superiores. Una opción terapéutica es la distalización molar, cuando se considera la corrección sin extracciones. Se presenta el caso de un paciente remitido desde la atención primaria de salud, con relación molar de distoclusión derecha, neutroclusion izquierda, resalte de seis milímetros y sobrepase corona completa. Previa confección de modelos de estudio e indicación de estudio radiográfico, se procedió a la corrección ortodóncica con la placa Cetlin, a la que se le realizaron algunas modificaciones. Se corrigió la distoclusión del primer molar permanente superior derecho hasta la neutroclusión; además del espacio requerido para el acomodamiento del canino superior derecho, se logró la corrección del sobrepase hasta un tercio de corona y se mejoró el resalte de seis a cuatro milímetros.

  18. The Relation between Vaporization Enthalpies and Viscosities: Eyring's Theory Applied to Selected Ionic Liquids.

    Science.gov (United States)

    Bonsa, Anne-Marie; Paschek, Dietmar; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Verevkin, Sergey P; Ludwig, Ralf

    2017-05-19

    Key properties for the use of ionic liquids as electrolytes in batteries are low viscosities, low vapor pressure and high vaporization enthalpies. Whereas the measurement of transport properties is well established, the determination of vaporization enthalpies of these extremely low volatile compounds is still a challenge. At a first glance both properties seem to describe different thermophysical phenomena. However, eighty years ago Eyring suggested a theory which related viscosities and vaporization enthalpies to each other. The model is based on Eyring's theory of absolute reaction rates. Recent attempts to apply Eyring's theory to ionic liquids failed. The motivation of our study is to show that Eyring's theory works, if the assumptions specific for ionic liquids are fulfilled. For that purpose we measured the viscosities of three well selected protic ionic liquids (PILs) at different temperatures. The temperature dependences of viscosities were approximated by the Vogel-Fulcher-Tamann (VFT) relation and extrapolated to the high-temperature regime up to 600 K. Then the VFT-data could be fitted to the Eyring-model. The values of vaporization enthalpies for the three selected PILs predicted by the Eyring model have been very close to the experimental values measured by well-established techniques. We conclude that the Eyring theory can be successfully applied to the chosen set of PILs, if the assumption that ionic pairs of the viscous flow in the liquid and the ionic pairs in the gas phase are similar is fulfilled. It was also noticed that proper transfer of energies can be only derived if the viscosities and the vaporization energies are known for temperatures close to the liquid-gas transition temperature. The idea to correlate easy measurable viscosities of ionic liquids with their vaporization enthalpies opens a new way for a reliable assessment of these thermodynamic properties for a broad range of ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGa

  19. Preliminary Results from Electric Arc Furnace Off-Gas Enthalpy Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Nimbalkar, Sachin U [ORNL; Thekdi, Arvind [E3M Inc; Keiser, James R [ORNL; Storey, John Morse [ORNL

    2015-01-01

    This article describes electric arc furnace (EAF) off-gas enthalpy models developed at Oak Ridge National Laboratory (ORNL) to calculate overall heat availability (sensible and chemical enthalpy) and recoverable heat values (steam or power generation potential) for existing EAF operations and to test ORNL s new EAF waste heat recovery (WHR) concepts. ORNL s new EAF WHR concepts are: Regenerative Drop-out Box System and Fluidized Bed System. The two EAF off-gas enthalpy models described in this paper are: 1.Overall Waste Heat Recovery Model that calculates total heat availability in off-gases of existing EAF operations 2.Regenerative Drop-out Box System Model in which hot EAF off-gases alternately pass through one of two refractory heat sinks that store heat and then transfer it to another gaseous medium These models calculate the sensible and chemical enthalpy of EAF off-gases based on the off-gas chemical composition, temperature, and mass flow rate during tap to tap time, and variations in those parameters in terms of actual values over time. The models provide heat transfer analysis for the aforementioned concepts to confirm the overall system and major component sizing (preliminary) to assess the practicality of the systems. Real-time EAF off-gas composition (e.g., CO, CO2, H2, and H2O), volume flow, and temperature data from one EAF operation was used to test the validity and accuracy of the modeling work. The EAF off-gas data was used to calculate the sensible and chemical enthalpy of the EAF off-gases to generate steam and power. The article provides detailed results from the modeling work that are important to the success of ORNL s EAF WHR project. The EAF WHR project aims to develop and test new concepts and materials that allow cost-effective recovery of sensible and chemical heat from high-temperature gases discharged from EAFs.

  20. Bodily distalization of molars with absolute anchorage.

    Science.gov (United States)

    Keles, Ahmet; Erverdi, Nejat; Sezen, Serdar

    2003-08-01

    Palatal implants have been used over the last two decades to eliminate headgear wear and to establish stationary anchorage. In this case report, the stability of a palatal implant for distalization of molars bodily and for anchorage maintenance was assessed. The implant was a stepped screw titanium (4.5 mm diameter x 8 mm length), and it was placed in the palatal region for orthodontic purposes. A surgical template containing a metal drill housing was prepared. Angulation of the drill housing was controlled according to the radiologic tracing of the maxilla transferred to a plaster cast section in the paramedian plane. The implant was placed using a noninvasive technique (incision, flap, and suture elimination) and left transmucosally to facilitate the surgical procedure and to reduce the number of operations. The paramedian region was selected (1) to avoid the connective tissues of the palatine suture and (2) because it is considered to be a suitable host site for implant placement. After three months of healing, the implant was osseointegrated and orthodontic treatment was initiated. For molar distalization, the Keles Slider appliance was modified and, instead of a Nance button, a palatal implant was used for anchorage. The results showed that the molars were distalized bodily at five months, and no anchorage loss was observed. At the end of the treatment, the smile was improved, and an ideal Class I molar and canine relationship, an ideal overbite, and an ideal overjet were all achieved. In conclusion, palatal implants can be used effectively for anchorage maintenance and in space-gaining procedures. Use of a three-dimensional surgical template eliminated implant placement errors, reduced chair time, minimized trauma to the tissues, and enhanced osseointegration. This method can be used effectively to achieve distalization of molars bodily without anchorage loss.

  1. Incidence of distal caries in mandibular second molars due to impacted third molars: Nonintervention strategy of asymptomatic third molars causes harm? A retrospective study.

    Science.gov (United States)

    Srivastava, Nikhil; Shetty, Akshay; Goswami, Rahul Dev; Apparaju, Vijay; Bagga, Vivek; Kale, Saurabh

    2017-01-01

    Removal of impacted third molars is the most common oral surgical procedure. Many investigators have questioned the necessity of removal in patients who are free of symptoms or associated pathologies. The aim of this retrospective study was to evaluate the incidence of caries on distal aspect of mandibular second molars in patients referred for corresponding third molar assessment and to identify its association with angular position and depth of the impacted mandibular third molars based on the classification of Pell and Gregory. Records of 150 patients with impacted third molar presenting to the Department of Oral and Maxillofacial Surgery, Sri Rajiv Gandhi College of Dental Sciences and Hospital, were assessed retrospectively. The radiographic angulation and depth of mandibular third molar impaction were determined and compared to determine the relationship with incidence of caries on the distal surface of the second molar. According to this study results, 37.5% cases show caries on the distal aspect of mandibular second molars. The incidence of caries with mesioangular impacted third molars was 55%. A majority of these mesioangular cases were Level B and Class I as per the Pell and Gregory classification. The prophylactic extraction of mandibular third molars is indicated if the angulation is between 30° and 70° and is justified by incidence of distal caries in the second molars.

  2. Measuring the enthalpies of interaction between glycine, L-cysteine, glycylglycine, and sodium dodecyl sulfate in aqueous solutions

    Science.gov (United States)

    Badelin, V. G.; Mezhevoi, I. N.; Tyunina, E. Yu.

    2017-03-01

    Calorimetric measurements of enthalpies of solution Δsol H m for glycine, L-cysteine, and glycylglycine in aqueous solutions of sodium dodecyl sulfate (SDS) with concentrations of up to 0.05 mol kg-1 are made. Standard enthalpy of solution Δsol H 0 and enthalpy of transfer Δtr H 0 of the dipeptide from water into mixed solvent are calculated. The calculated enthalpy coefficients of paired interactions of amino acids and dipeptide with SDS prove to be positive. Hydrophobic interactions between the biomolecules and SDS are found to have a major impact on the enthalpies of interaction in the three-component systems under study, within the indicated range of concentrations.

  3. Study of root canal accessibility in human primary molars.

    Science.gov (United States)

    Aminabadi, Naser A; Farahani, Ramin M Z; Gajan, Esrafil B

    2008-03-01

    The aim of the present study was to provide a general scheme for pulpectomy of primary molars that may be useful for decision-making about negotiation of root canals and selection of appropriate instruments. A total of 160 vital primary molars in 85 patients (40 males, 45 females) aged 4-6 years were selected. After taking primary radiographs, local anesthesia was induced, and the teeth were isolated using a rubber dam. Canal accessibility index (CAI) and tooth accessibility index (TAI) were calculated according to initial file size. Mandibular first molars had either three canals (79.2%) or four canals (20.8%), and all second molars had four canals. Maxillary first molars had three canals and second molars had either three canals (70.9%) or four canals (29.1%). Lower accessibility of the mandibular first molar distobuccal root accounted for the lower accessibility of these teeth in comparison with mandibular second molars. While three-canal maxillary second molars were more accessible due to the lower accessibility of the distobuccal canal of the maxillary first molar, poor accessibility of the distal canal in four-canal second molars was responsible for the difficult accessibility of these teeth. In conclusion, it seems that the accessibility of a single canal in each tooth determines the difficulty of accessibility for any given tooth. Moreover, while primary second molars are more accessible than first molars, all of them are negotiable.

  4. An innovative technique to distalize maxillary molar using microimplant supported rapid molar distalizer

    Directory of Open Access Journals (Sweden)

    Meenu Goel

    2013-01-01

    Full Text Available Introduction: In recent years, enhancements in implants have made their use possible as a mode of absolute anchorage in orthodontic patients. In this paper, the authors have introduced an innovative technique to unilaterally distalize the upper left 1 st molar to obtain an ideal Class I molar relationship from a Class II existing molar relationship with an indigenous designed distalizer. Clinical Innovation: For effective unilateral diatalization of molar, a novel cantilever sliding jig assembly was utilized with coil spring supported by a buccally placed single micro implant. The results showed 3 mm of bodily distalization with 1 mm of intrusion and 2° of distal tipping of upper left 1 st molar in 1.5 months. Discussion: This appliance is relatively easy to insert, well-tolerated, and requires minimal patient cooperation compared to other present techniques of molar distalization. Moreover, it is particularly useful in cases that are Class II on one side and Class I on the other, with a minor midline discrepancy and nominal overjet. Patient acceptance level was reported to be within patients physiological and comfort limits.

  5. Mandibular molar crown-topography, a biological predisposing ...

    African Journals Online (AJOL)

    Mandibular molar crown-topography, a biological predisposing factor to development of caries – a post-mortem analysis of 2500 extracted lower permanent molars at the dental centre, University of Benin teaching hospital.

  6. [The extraction of the lower third molars: germectomy or late avulsion?].

    Science.gov (United States)

    Chiapasco, M; Crescentini, M; Romanoni, G

    1994-05-01

    Lower third molars show the highest incidence of impaction and have been held responsible for pathologies such as pericoronitis, periodontitis, second molars tooth-crown resorption, pain, cysts or odontogenic tumors, primary or secondary crowding of the dentition. Early removal of these teeth to prevent the overmentioned problems is widely acknowledged, as many studies demonstrated a direct correlation between age and incidence of complications. These studies mostly refer to adult patients, while studies about germectomies are few. Because recent contributions showed that the risk of development of these pathologies in presence of impacted third molars is quite low while a certain morbidity associated to this procedure may be expected, a very careful risk to benefit ratio must be considered. The purpose of this study was therefore to compare the incidence of complications and side effects in three age groups, in order to obtain some informations about the choice of the best moment for operation. The patients, 462 females and 406 males, were divided, according to age, in the following three groups: group A included patients from 9 to 16 years; group B included patients from 17 to 24 years; group C included patients over 24 years. All patients were treated under local anesthesia; surgical procedure and instruments were standardized. In group A, formed by 500 germectomies, the incidence of complications was 2.6% (10 instances of secondary infections, 2 instances of trismus, 1 instance of excessive postoperative bleeding). Group B included 570 procedures and the incidence of complications was 2.8% (3 instances of alveolar osteitis, 7 instances of secondary infections, 2 instances of excessive postoperative bleeding, 2 instances od second molar lesions, 1 instance of inferior alveolar nerve paresthesia, 1 instance of trismus). Group C included 430 procedures and the incidence of complications was 7.4% (2 instances of second molar lesions, 9 instances of alveolar

  7. Study of Kissing Molars in Turkish Population Sample

    African Journals Online (AJOL)

    2017-06-28

    Jun 28, 2017 ... Mandibular third molars are the most common unerupted teeth; retention of the mandibular second molar is much less common.[1] Simultaneous retention of both teeth is quite rare. “Kissing molars” (KMs) are an interesting finding in permanent mandibular molar teeth. KMs or “rosette formation” was first ...

  8. Ruptured tubal molar pregnancy | Yakasai | Nigerian Journal of ...

    African Journals Online (AJOL)

    Molar pregnancies in most instances develop within the uterine cavity, but may occur at any site. Ectopic molar pregnancy is a rare event. The objective of this study was to present a case of ruptured tubal molar gestation, discuss its clinical features and ways to improve diagnostic accuracy. A 35.year.old woman presented ...

  9. Molar tooth sign - looking beyond the obvious | Mahomed | SA ...

    African Journals Online (AJOL)

    The molar tooth sign was initially identified in Joubert syndrome, named after Marie Joubert who first described it in 1968 as a rare autosomal recessive disorder characterised by the neuroradiological hallmark of the molar tooth sign caused by cerebellar vermian hypoplasia. Subsequently, it emerged that the molar tooth ...

  10. Molar-incisor-hypomineralisation: a literature review.

    Science.gov (United States)

    Willmott, N S; Bryan, R A E; Duggal, M S

    2008-12-01

    Molar-Incisor-Hypomineralisation (MIH) is a qualitative defect of 1-4 first permanent molars with or without the maxillary and mandibular permanent incisors. It seems to have been recognised first in the 1970s and prevalence varies between 2.8% and 25%, dependent upon the study. The dental literature was searched using a number of key terms entered into MEDLINE, the reference list of each paper as located was examined for further papers that had been missed in the initial search. The review of the literature showed that teeth that are affected indicate a systemic cause at around the time of birth; investigators have put forward a number of possible causes; asthma, pneumonia, upper respiratory tract infections, otitis media, antibiotics, dioxins in mother's milk, tonsillitis and tonsillectomy and exanthamatous fevers of childhood. However, at the present time the aetiology remains unclear. Treatment of the affected permanent first molars can include restorations using adhesive intra-coronal restorations to extra-coronal restorations (e.g. preformed metal crowns). There is little evidence to support one option over another. In severe cases extraction at the optimum time may be the best option; allowing the permanent second molars to come forwards. There is little improvement in affected anterior teeth with microabrasion and direct or indirect composite resin restorations may be appropriate in some children. Ultrastructural and biochemical make up of MIH affected teeth seem to have been investigated less than other areas. It is important that children with MIH are diagnosed as early as possible and managed appropriately; this will involve multidisciplinary input.

  11. Ceramic onlay for endodontically treated mandibular molar

    OpenAIRE

    Roopadevi Garlapati; Bhuvan Shome Venigalla; Shekhar Kamishetty; Jayaprakash Thumu

    2014-01-01

    Restoration of endodontically treated teeth is important for the success of endodontic treatment. In full coverage restorations, maximum amount of tooth structure is compromised, so as to conserve the amount of tooth structure partial coverage restorations, can be preferred. This case report is on fabrication of a conservative tooth colored restoration for an endodontically treated posterior tooth. A 22-year-old male patient presented with pain in the mandibular left first molar. After endodo...

  12. Generalized enthalpy based equation of state for multi-component mixtures

    Science.gov (United States)

    Nayak, Bishnupriya; Menon, S. V. G.

    2017-04-01

    An equation of state using pressure and temperature as independent variables, including non-equilibrium thermal energies of components and explicit accounting of thermal electron effects, is formulated for multi component mixtures. As pressure equilibration is faster in mixtures, this approach is more suited than earlier schemes using Mie-Gruneisen equation of state. Due to the reliance on enthalpy, in lieu of energy, it is directly applicable also to treat porosity effects. The formulation leads to an expression for mixture volume which consists of a term depended on enthalpy differences of components, in addition to those depending on average mixture parameters. A method to estimate non-equilibrium thermal effects, using component Hugoniot to compute non-equilibrium temperatures, is also proposed in this work. Results obtained for two and three component mixtures compare well with experimental Hugoniot data.

  13. The influence of facies heterogeneity on the doublet performance in low-enthalpy geothermal sedimentary reservoirs

    DEFF Research Database (Denmark)

    Crooijmans, R. A.; Willems, C. J L; Nick, Hamid

    2016-01-01

    A three-dimensional model is used to study the influence of facies heterogeneity on energy production under different operational conditions of low-enthalpy geothermal doublet systems. Process-based facies modelling is utilised for the Nieuwerkerk sedimentary formation in the West Netherlands Basin...... and the energy recovery rate for different discharge rates and the production temperature (Tmin) above which the doublet is working. With respect to the results, we propose a design model to estimate the life time and energy recovery rate of the geothermal doublet. The life time is estimated as a function of N...... errors in predicting the life time of low-enthalpy geothermal systems for N/G values below 70%....

  14. Generalized enthalpy model of a high-pressure shift freezing process

    KAUST Repository

    Smith, N. A. S.

    2012-05-02

    High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work, we present a generalized enthalpy model of the high-pressure shift freezing process. The model includes the effects of pressure on conservation of enthalpy and incorporates the freezing point depression of non-dilute food samples. In addition, the significant heat-transfer effects of convection in the pressurizing medium are accounted for by solving the two-dimensional Navier-Stokes equations. We run the model for several numerical tests where the food sample is agar gel, and find good agreement with experimental data from the literature. © 2012 The Royal Society.

  15. Air to air fixed plate enthalpy heat exchanger, performance variation and energy analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nasif, Mohammad Shakir [Universiti Teknologi Petronas, Bandar Seri Iskandar (Malaysia); Alwaked, Rafat [Prince Mohammad Bin Fahd University, Al Khobar (Saudi Arabia); Behnia, Masud [University of Sydney, Sydney (Australia); Morrison, Graham [The University of New South Wales, Sydney (Australia)

    2013-11-15

    The thermal performance of a Z shape enthalpy heat exchanger utilising 70 gsm Kraft paper as the heat and moisture transfer surface has been investigated. Effects of different inlet air humidity ratio conditions on the heat exchanger effectiveness and on the energy recovered by the heat exchanger have been the main focus of this investigation. A typical air conditioning cooling coil which incorporates an enthalpy heat exchanger has been modelled for tropical climate. Under test conditions, results have shown that latent effectiveness and the moisture resistance coefficient have strong dependency on the inlet air humidity ratio. Moreover, the latent effectiveness has been found to be strongly dependent on the moisture resistance coefficient rather than the convective mass transfer coefficient. Finally, annual energy analysis for Singapore weather conditions have also shown that energy recovered under variable inlet air conditions is 15% less than that recovered under constant inlet air conditions for the same heat exchanger.

  16. Down-Hole Heat Exchangers: Modelling of a Low-Enthalpy Geothermal System for District Heating

    Directory of Open Access Journals (Sweden)

    M. Carlini

    2012-01-01

    Full Text Available In order to face the growing energy demands, renewable energy sources can provide an alternative to fossil fuels. Thus, low-enthalpy geothermal plants may play a fundamental role in those areas—such as the Province of Viterbo—where shallow groundwater basins occur and conventional geothermal plants cannot be developed. This may lead to being fuelled by locally available sources. The aim of the present paper is to exploit the heat coming from a low-enthalpy geothermal system. The experimental plant consists in a down-hole heat exchanger for civil purposes and can supply thermal needs by district heating. An implementation in MATLAB environment is provided in order to develop a mathematical model. As a consequence, the amount of withdrawable heat can be successfully calculated.

  17. Enthalpy of solution of biuret in various aqueous electrolyte solutions and in an urea solution

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Hisashi; Murakami, Sachio (Osaka City Univ. (Japan))

    1989-06-30

    Enthalpies of biuret which is simplest amido acid and does not have hydrophobic group, in various aqueous solutions and in urea solution were measured at 298.15K to clarify the influence of salt on polymer conformal changes of organism or structure and functions of membrane. The isoperibol calorimeter where the quartz thermometer was used as the thermal sensor, was used in the measurement. The performance of this calorimeter was tested by comparing measurements with values in references. From the analysis of enthalpies of biuret solutions, following results of solute-solute-solvent interactions could be obtained: the rate where biuret destroys water structure is smaller in salt solutions than in aqueous solutions and the tendency depends on the ion size; ion-water interaction weakens owing to the ion-biuret interaction in salt solution of biuret; and water molecules are made free. 25 refs., 4 figs., 5 tabs.

  18. Free Energy, Enthalpy and Entropy from Implicit Solvent End-Point Simulations

    Directory of Open Access Journals (Sweden)

    Federico Fogolari

    2018-02-01

    Full Text Available Free energy is the key quantity to describe the thermodynamics of biological systems. In this perspective we consider the calculation of free energy, enthalpy and entropy from end-point molecular dynamics simulations. Since the enthalpy may be calculated as the ensemble average over equilibrated simulation snapshots the difficulties related to free energy calculation are ultimately related to the calculation of the entropy of the system and in particular of the solvent entropy. In the last two decades implicit solvent models have been used to circumvent the problem and to take into account solvent entropy implicitly in the solvation terms. More recently outstanding advancement in both implicit solvent models and in entropy calculations are making the goal of free energy estimation from end-point simulations more feasible than ever before. We review briefly the basic theory and discuss the advancements in light of practical applications.

  19. Generalized enthalpy based equation of state for multi-component mixtures

    Directory of Open Access Journals (Sweden)

    Bishnupriya Nayak

    2017-04-01

    Full Text Available An equation of state using pressure and temperature as independent variables, including non-equilibrium thermal energies of components and explicit accounting of thermal electron effects, is formulated for multi component mixtures. As pressure equilibration is faster in mixtures, this approach is more suited than earlier schemes using Mie-Gruneisen equation of state. Due to the reliance on enthalpy, in lieu of energy, it is directly applicable also to treat porosity effects. The formulation leads to an expression for mixture volume which consists of a term depended on enthalpy differences of components, in addition to those depending on average mixture parameters. A method to estimate non-equilibrium thermal effects, using component Hugoniot to compute non-equilibrium temperatures, is also proposed in this work. Results obtained for two and three component mixtures compare well with experimental Hugoniot data.

  20. Accurate Computed Enthalpies of Spin Crossover in Iron and Cobalt Complexes

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta; Cirera, J

    2009-01-01

    Despite their importance in many chemical processes, the relative energies of spin states of transition metal complexes have so far been haunted by large computational errors. By the use of six functionals, B3LYP, BP86, TPSS, TPSSh, M06L, and M06L, this work studies nine complexes (seven with iron...... and two with cobalt) for which experimental enthalpies of spin crossover are available. It is shown that such enthalpies can be used as quantitative benchmarks of a functional's ability to balance electron correlation in both the involved states. TPSSh achieves an unprecedented mean absolute error...... effects of first-row transition metal systems. Furthermore, it is shown that given an experimental structure of an iron complex, TPSSh can predict the electronic state corresponding to that experimental structure. We recommend this functional as current state-of-the-art for studying spin crossover...

  1. Enthalpy measurement of coal-derived liquids. Quarterly technical progress report, July-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1980-09-15

    Equipment modifications to a Freon 11 boil-off type calorimeter are described. The calorimetric system was used to measure the enthalpies of thiophene experimentally. Data were taken over a temperature range of 100/sup 0/F to 750/sup 0/F at pressures of 50, 100, 200, 400, 600, 825.9 (the critical), 1000, and 1500 psia. Thermodynamic properties derived from the data are compared to values in the literature, and the agreement is exceptionally good. The data are then compared directly to results calculated by means of two correlations: a modification of the BWR equation of state by Kesler and Lee, and a modified SRK equation of state method. Both correlations are found to work well in predicting the enthalpy of thiophene.

  2. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, April-June 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1986-07-31

    Enthalpy measurements for the m-cresol/tetralin binary system, and the quinoline/tertralin binary system have been completed and are included. A calibration check on the calorimeter was performed and is presented in Appendix C. Vapor liquid equilibria measurements for the quinoline/tetralin system have been completed for four isotherms; 250, 275, 300, and 325/sup 0/C. These results and a summary of progress to date for the VLE apparatus are in the appendix at the end of this report. Also, preliminary work has begun on the quinoline/m-cresol/tetralin ternary system. Correlational work has consisted of the development of mathematical expressions for fugacity and enthalpy using various combinations of mixing rules and equations of state discussed in earlier reports. Also maximum likelihood routines has been written to determine the necessary parameters for binary data obtained in this investigation.

  3. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, April-June 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-07-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the fourth quarter enthalpy measurements and a preliminary analysis on tetralin data were completed. A new pump was installed eliminating the need for a pressure adjuster in the pressure system. This pump provides pulse free flow even at a pressure of 1500 psia. During the next quarter, measurements on the binary system m-cresol/tetralin will begin. Vapor liquid equilibria measurements for the m-cresol/quinoline system have begun for four isotherms. Preliminary results have been included in this report. These measurements will be completed in the next quarter and work will be started on the m-cresol/tetralin system. 12 refs., 5 figs., 4 tabs.

  4. Dehydration enthalpy of alkali-cations-exchanged montmorillonite from thermogravimetric analysis.

    Science.gov (United States)

    Kharroubi, M; Balme, S; Henn, F; Giuntini, J C; Belarbi, H; Haouzi, A

    2009-01-15

    Dehydration of a series of homoionic alkali-exchanged montmorillonites is studied at different treatment temperatures by means of thermogravimetric analysis. More specifically, we investigate the last stages of dehydration when the number of adsorbed water molecules corresponds, at maximum, to a monolayer. Weight losses are measured at several constant temperatures as a function of time. Application of Van't Hoff's law yields the dehydration enthalpy. Trends and data similar to those reported from other experimental conditions are found. Comparison with X-ray data and with the dissociation enthalpy of alkali cation/water complexes shows that dehydration of weakly hydrated homoionic alkali montmorillonites results from the competition between opposite energy contributions due to (i) the cation solvation, (ii) the hydration of the silicate interlayer surface, and (iii) the structural swelling. So, depending on the balance between these various energy contributions, different behaviors are observed according to the nature of the alkali cations.

  5. Excessive masturbation after epilepsy surgery.

    Science.gov (United States)

    Ozmen, Mine; Erdogan, Ayten; Duvenci, Sirin; Ozyurt, Emin; Ozkara, Cigdem

    2004-02-01

    Sexual behavior changes as well as depression, anxiety, and organic mood/personality disorders have been reported in temporal lobe epilepsy (TLE) patients before and after epilepsy surgery. The authors describe a 14-year-old girl with symptoms of excessive masturbation in inappropriate places, social withdrawal, irritability, aggressive behavior, and crying spells after selective amygdalohippocampectomy for medically intractable TLE with hippocampal sclerosis. Since the family members felt extremely embarrassed, they were upset and angry with the patient which, in turn, increased her depressive symptoms. Both her excessive masturbation behavior and depressive symptoms remitted within 2 months of psychoeducative intervention and treatment with citalopram 20mg/day. Excessive masturbation is proposed to be related to the psychosocial changes due to seizure-free status after surgery as well as other possible mechanisms such as Kluver-Bucy syndrome features and neurophysiologic changes associated with the cessation of epileptic discharges. This case demonstrates that psychiatric problems and sexual changes encountered after epilepsy surgery are possibly multifactorial and in adolescence hypersexuality may be manifested as excessive masturbation behavior.

  6. An evaluation of interferences in heat production from low enthalpy geothermal doublets systems

    DEFF Research Database (Denmark)

    Willems, Cees J. L.; Nick, Hamidreza M.; Weltje, Gert Jan

    2017-01-01

    Required distance between doublet systems in low enthalpy geothermal heat exploitation is often not fully elucidated. The required distance aims to prevent negative interference influencing the utilisation efficiency of doublet systems. Currently production licence areas are often issued based...... and minimal required production temperature. The results of this study can be used to minimize negative interference or optimise positive interference aiming at improving geothermal doublet deployment efficiency. (C) 2017 The Authors. Published by Elsevier Ltd....

  7. Equivalent Temperature-Enthalpy Diagram for the Study of Ejector Refrigeration Systems

    Directory of Open Access Journals (Sweden)

    Mohammed Khennich

    2014-05-01

    Full Text Available The Carnot factor versus enthalpy variation (heat diagram has been used extensively for the second law analysis of heat transfer processes. With enthalpy variation (heat as the abscissa and the Carnot factor as the ordinate the area between the curves representing the heat exchanging media on this diagram illustrates the exergy losses due to the transfer. It is also possible to draw the paths of working fluids in steady-state, steady-flow thermodynamic cycles on this diagram using the definition of “the equivalent temperature” as the ratio between the variations of enthalpy and entropy in an analyzed process. Despite the usefulness of this approach two important shortcomings should be emphasized. First, the approach is not applicable for the processes of expansion and compression particularly for the isenthalpic processes taking place in expansion valves. Second, from the point of view of rigorous thermodynamics, the proposed ratio gives the temperature dimension for the isobaric processes only. The present paper proposes to overcome these shortcomings by replacing the actual processes of expansion and compression by combinations of two thermodynamic paths: isentropic and isobaric. As a result the actual (not ideal refrigeration and power cycles can be presented on equivalent temperature versus enthalpy variation diagrams. All the exergy losses, taking place in different equipments like pumps, turbines, compressors, expansion valves, condensers and evaporators are then clearly visualized. Moreover the exergies consumed and produced in each component of these cycles are also presented. The latter give the opportunity to also analyze the exergy efficiencies of the components. The proposed diagram is finally applied for the second law analysis of an ejector based refrigeration system.

  8. Kinetic evidence of an apparent negative activation enthalpy in an organocatalytic process

    KAUST Repository

    Han, Xiao

    2013-08-30

    A combined kinetic and computational study on our tryptophan-based bifunctional thiourea catalyzed asymmetric Mannich reactions reveals an apparent negative activation enthalpy. The formation of the pre-transition state complex has been unambiguously confirmed and these observations provide an experimental support for the formation of multiple hydrogen bonding network between the substrates and the catalyst. Such interactions allow the creation of a binding cavity, a key factor to install high enantioselectivity.

  9. Dominant Alcohol-Protein Interaction via Hydration-Enabled Enthalpy-Driven Binding Mechanism

    Science.gov (United States)

    Chong, Yuan; Kleinhammes, Alfred; Tang, Pei; Xu, Yan; Wu, Yue

    2015-01-01

    Water plays an important role in weak associations of small drug molecules with proteins. Intense focus has been on binding-induced structural changes in the water network surrounding protein binding sites, especially their contributions to binding thermodynamics. However, water is also tightly coupled to protein conformations and dynamics, and so far little is known about the influence of water-protein interactions on ligand binding. Alcohols are a type of low-affinity drugs, and it remains unclear how water affects alcohol-protein interactions. Here, we present alcohol adsorption isotherms under controlled protein hydration using in-situ NMR detection. As functions of hydration level, Gibbs free energy, enthalpy, and entropy of binding were determined from the temperature dependence of isotherms. Two types of alcohol binding were found. The dominant type is low-affinity nonspecific binding, which is strongly dependent on temperature and the level of hydration. At low hydration levels, this nonspecific binding only occurs above a threshold of alcohol vapor pressure. An increased hydration level reduces this threshold, with it finally disappearing at a hydration level of h~0.2 (g water/g protein), gradually shifting alcohol binding from an entropy-driven to an enthalpy-driven process. Water at charged and polar groups on the protein surface was found to be particularly important in enabling this binding. Although further increase in hydration has smaller effects on the changes of binding enthalpy and entropy, it results in significant negative change in Gibbs free energy due to unmatched enthalpy-entropy compensation. These results show the crucial role of water-protein interplay in alcohol binding. PMID:25856773

  10. Thermodynamics of Uranyl Minerals: Enthalpies of Formation of Uranyl Oxide Hydrates

    Energy Technology Data Exchange (ETDEWEB)

    K. Kubatko; K. Helean; A. Navrotsky; P.C. Burns

    2005-05-11

    The enthalpies of formation of seven uranyl oxide hydrate phases and one uranate have been determined using high-temperature oxide melt solution calorimetry: [(UO{sub 2}){sub 4}O(OH){sub 6}](H{sub 2}O){sub 5}, metaschoepite; {beta}-UO{sub 2}(OH){sub 2}; CaUO{sub 4}; Ca(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 8}, becquerelite; Ca(UO{sub 2}){sub 4}O{sub 3}(OH){sub 4}(H{sub 2}O){sub 2}; Na(UO{sub 2})O(OH), clarkeite; Na{sub 2}(UO{sub 2}){sub 6}O{sub 4}(OH){sub 6}(H{sub 2}O){sub 7}, the sodium analogue of compreignacite and Pb{sub 3}(UO{sub 2}){sub 8}O{sub 8}(OH){sub 6}(H{sub 2}O){sub 2}, curite. The enthalpy of formation from the binary oxides, {Delta}H{sub f-ox}, at 298 K was calculated for each compound from the respective drop solution enthalpy, {Delta}H{sub ds}. The standard enthalpies of formation from the elements, {Delta}H{sub f}{sup o}, at 298 K are -1791.0 {+-} 3.2, -1536.2 {+-} 2.8, -2002.0 {+-} 3.2, -11389.2 {+-} 13.5, -6653.1 {+-} 13.8, -1724.7 {+-} 5.1, -10936.4 {+-} 14.5 and -13163.2 {+-} 34.4 kJ mol{sup -1}, respectively. These values are useful in exploring the stability of uranyl oxide hydrates in auxiliary chemical systems, such as those expected in U-contaminated environments.

  11. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, July-September 1984

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1984-10-30

    Work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. Calorimetric measurements were made on pure quinoline. These measurements extended the range of previous measurements which had been made on quinoline, and improved the accuracy of previously measured results in the vapor phase when the quinoline sample used was believed to contain considerable quantities of water. 5 figures, 4 tables.

  12. Simulations of Nanocrystals Under Pressure: Combining Electronic Enthalpy and Linear-Scaling Density-Functional Theory

    OpenAIRE

    Corsini, NR; Greco, A.; Hine, ND; Molteni, C.; Haynes, PD

    2013-01-01

    We present an implementation in a linear-scaling density-functional theory code of an electronic enthalpy method, which has been found to be natural and efficient for the ab initio calculation of finite systems under hydrostatic pressure. Based on a definition of the system volume as that enclosed within an electronic density isosurface [M. Cococcioni, F. Mauri, G. Ceder, and N. Marzari, Phys. Rev. Lett. 94, 145501 (2005)], it supports both geometry optimizations and molecular dynamics simula...

  13. Crying - excessive (0-6 months)

    Science.gov (United States)

    ... provider will check the infant's growth and development. Antibiotics may be prescribed if the baby has a bacterial infection. Alternative Names Infants - excessive crying; Well child - excessive crying ...

  14. Pattern of mandibular third molar impaction and its association to caries in mandibular second molar: A clinical variant

    Directory of Open Access Journals (Sweden)

    V K Prajapati

    2017-01-01

    Conclusion: According to this study, pattern of mandibular third molar impaction is in association to caries in mandibular second molar. More future studies are needed. In addition, the results of the present study can be used to screen and inform the patients about the possibility of caries in relation to third molar mandibular impaction.

  15. Influence of unilateral maxillary first molar extraction treatment on second and third molar inclination in Class II subdivision patients

    NARCIS (Netherlands)

    Livas, Christos; Pandis, Nikolaos; Booij, Johan Willem; Halazonetis, Demetrios J.; Katsaros, Christos; Ren, Yijin

    Objective: To assess the maxillary second molar (M2) and third molar (M3) inclination following orthodontic treatment of Class II subdivision malocclusion with unilateral maxillary first molar (M1) extraction. Materials and Methods: Panoramic radiographs of 21 Class II subdivision adolescents (eight

  16. Dissolution enthalpies of L-proline and its interactions with methanol, 2-propanol, ethylene glycol, and glycerin in aqueous solution at 298.15 K

    Science.gov (United States)

    Korolev, V. P.; Antonova, O. A.; Smirnova, N. L.

    2010-12-01

    The dissolution enthalpies of L-proline in mixtures of water with methanol, 2-propanol, ethylene glycol, and glycerin were measured calorimetrically at 298.15 K. The enthalpy coefficients of the interaction of proline with alcohols in aqueous solutions were determined. The enthalpy coefficients of the pair interaction of proline and glycine with alcohols were shown to be directly proportional.

  17. The relationship between discharge capacity of LaNi{sub 5} type hydrogen storage alloys and formation enthalpy

    Energy Technology Data Exchange (ETDEWEB)

    Ma Xiaobo; Wei Xuedong; Dong Hui [State Key Laboratory of Mechanical Behavior of Materials, School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Liu Yongning, E-mail: ynliu@mail.xjtu.edu.c [State Key Laboratory of Mechanical Behavior of Materials, School of Material Science and Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2010-02-04

    The formation enthalpy of LaNi{sub 5} type hydrogen storage alloys has been calculated using a semi-empirical formula that takes into account the electronegativities, the atomic size, and the electron concentration of each constituent element in the alloys. Through our calculations, it was found that the formation enthalpy of the alloys is directly related to the discharge capacities of the alloys. When the absolute value of formation enthalpy decreases, the discharge capacity increases. The result provides a valuable reference for alloy design.

  18. Influence of Countercation Hydration Enthalpies on the Formation of Molecular Complexes: A Thorium-Nitrate Example.

    Science.gov (United States)

    Jin, Geng Bang; Lin, Jian; Estes, Shanna L; Skanthakumar, S; Soderholm, L

    2017-12-13

    The influence of countercations (A n+ ) in directing the composition of monomeric metal-ligand (ML) complexes that precipitate from solution are often overlooked despite the wide usage of A n+ in materials synthesis. Herein, we describe a correlation between the composition of ML complexes and A + hydration enthalpies found for two related series of thorium (Th)-nitrate molecular compounds obtained by evaporating acidic aqueous Th-nitrate solutions in the presence of A + counterions. Analyses of their chemical composition and solid-state structures demonstrate that A + not only affects the overall solid-state packing of the Th-nitrato complexes but also influences the composition of the Th-nitrato monomeric anions themselves. Trends in composition and structure are found to correlate with A + hydration enthalpies, such that the A + with smaller hydration enthalpies associate with less hydrated and more anionic Th-nitrato complexes. This perspective, broader than the general assumption of size and charge as the dominant influence of A n+ , opens a new avenue for the design and synthesis of targeted metal-ligand complexes.

  19. Constant enthalpy change value during pyrophosphate hydrolysis within the physiological limits of NaCl.

    Science.gov (United States)

    Wakai, Satoshi; Kidokoro, Shun-ichi; Masaki, Kazuo; Nakasone, Kaoru; Sambongi, Yoshihiro

    2013-10-11

    A decrease in water activity was thought to result in smaller enthalpy change values during PPi hydrolysis, indicating the importance of solvation for the reaction. However, the physiological significance of this phenomenon is unknown. Here, we combined biochemistry and calorimetry to solve this problem using NaCl, a physiologically occurring water activity-reducing reagent. The pyrophosphatase activities of extremely halophilic Haloarcula japonica, which can grow at ∼4 M NaCl, and non-halophilic Escherichia coli and Saccharomyces cerevisiae were maximal at 2.0 and 0.1 M NaCl, respectively. Thus, halophilic and non-halophilic pyrophosphatases exhibit distinct maximal activities at different NaCl concentration ranges. Upon calorimetry, the same exothermic enthalpy change of -35 kJ/mol was obtained for the halophile and non-halophiles at 1.5-4.0 and 0.1-2.0 M NaCl, respectively. These results show that solvation changes caused by up to 4.0 M NaCl (water activity of ∼0.84) do not affect the enthalpy change in PPi hydrolysis. It has been postulated that PPi is an ATP analog, having a so-called high energy phosphate bond, and that the hydrolysis of both compounds is enthalpically driven. Therefore, our results indicate that the hydrolysis of high energy phosphate compounds, which are responsible for biological energy conversion, is enthalpically driven within the physiological limits of NaCl.

  20. Active Thermochemical Tables: Sequential Bond Dissociation Enthalpies of Methane, Ethane, and Methanol and the Related Thermochemistry.

    Science.gov (United States)

    Ruscic, Branko

    2015-07-16

    Active Thermochemical Tables (ATcT) thermochemistry for the sequential bond dissociations of methane, ethane, and methanol systems were obtained by analyzing and solving a very large thermochemical network (TN). Values for all possible C-H, C-C, C-O, and O-H bond dissociation enthalpies at 298.15 K (BDE298) and bond dissociation energies at 0 K (D0) are presented. The corresponding ATcT standard gas-phase enthalpies of formation of the resulting CHn, n = 4-0 species (methane, methyl, methylene, methylidyne, and carbon atom), C2Hn, n = 6-0 species (ethane, ethyl, ethylene, ethylidene, vinyl, ethylidyne, acetylene, vinylidene, ethynyl, and ethynylene), and COHn, n = 4-0 species (methanol, hydroxymethyl, methoxy, formaldehyde, hydroxymethylene, formyl, isoformyl, and carbon monoxide) are also presented. The ATcT thermochemistry of carbon dioxide, water, hydroxyl, and carbon, oxygen, and hydrogen atoms is also included, together with the sequential BDEs of CO2 and H2O. The provenances of the ATcT enthalpies of formation, which are quite distributed and involve a large number of relevant determinations, are analyzed by variance decomposition and discussed in terms of principal contributions. The underlying reasons for periodic appearances of remarkably low and/or unusually high BDEs, alternating along the dissociation sequences, are analyzed and quantitatively rationalized. The present ATcT results are the most accurate thermochemical values currently available for these species.

  1. Spatial variability of enthalpy in broiler house during the heating phase

    Directory of Open Access Journals (Sweden)

    Patrícia F. P. Ferraz

    2016-06-01

    Full Text Available ABSTRACT The thermal environment inside a broiler house has a great influence on animal welfare and productivity during the production phase. Enthalpy is a thermodynamic property that has been proposed to evaluate the internal broiler house environment, for being an indicator of the amount of energy contained in a mixture of water vapor and dry air. Therefore, this study aimed to characterize the spatial variability of enthalpy in a broiler house during the heating phase using geostatistics. The experiment was conducted in the spring season, in a commercial broiler house with heating system consisting of two furnaces that heat the air indirectly, in the first 14 days of the birds' life. It was possible to characterize enthalpy variability using geostatistical techniques, which allowed observing the spatial dependence through kriging maps. The analyses of the maps allowed observing problems in the heating system in regions inside the broiler house, which may cause a thermal discomfort to the animals besides productive and economic losses.

  2. Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons

    Science.gov (United States)

    Moreno-Piraján, Juan Carlos; Blanco, Diego; Giraldo, Liliana

    2012-01-01

    An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g−1 for catechol aqueous solutions in a range of 20 at 1500 mg·L−1. PMID:22312237

  3. Enthalpy measurement of coal-derived liquids. Technical progress report, November 1982-January 1983

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1983-02-22

    The objective of this research is to measure the enthalpy for representative coal-derived liquids and model compounds over the pressure and temperature regions most likely to be encountered in both liquefaction and processing systems, and to prepare from the data an enthalpy correlation suitable for process design calculations. The correlational effort this past quarter on the enthalpy of coal-derived syncrudes and model compounds has emphasized the experimental determination of a correlating factor for association in coal liquids. As in previous work, the degree of association is to be related to cryoscopic molecular weight determinations on the coal liquids. To this end, work on and an evaluationof a cryoscopic molecular weight apparatus was completed this quarter. Molecular weights of coal liquids determined by the standard Beckman freezing point depression apparatus were consistently low (5 to 10%). After modifications of the apparatus, it was tested with the following compounds: hexane, dodecane, m-xylene and naphthalene. Benzene was the solvent used. However, the molecular weight measurements were again consistently lower than the true values, and in many cases the experimental error was greater than that of the Beckman apparatus.

  4. Molar tubal ectopic pregnancy: Report of two cases.

    Science.gov (United States)

    Mbarki, Chaouki; Jerbi, Emna; Hsayaoui, Najeh; Zouari, Fatma; Ben Brahim, Ehsen; Oueslati, Hedhili

    2015-06-01

    Ectopic molar pregnancy is a rare occurrence and consequently not often considered as a diagnostic possibility. We report two cases of molar hydatidiform tubal pregnancy. Diagnosis of ectopic pregnancy was confirmed on clinical biological and sonographic investigations. Diagnosis of molar pregnancy was done on histopathology. The clinical course was favorable for both patients. Although rare, molar changes can occur at any site of an ectopic pregnancy. Clinical diagnosis of a molar pregnancy is difficult but histopathology is the gold standard for diagnosis. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  5. One year Survival Rate of Ketac Molar versus Vitro Molar for Occlusoproximal ART Restorations: a RCT.

    Science.gov (United States)

    Anna Luisa de Brito, Pacheco; Isabel Cristina, Olegário; Clarissa Calil, Bonifácio; Ana Flávia Bissoto, Calvo; José Carlos Pettorossi, Imparato; Daniela Prócida, Raggio

    2017-11-06

    Good survival rates for single-surface Atraumatic Restorative Treatment (ART) restorations have been reported, while multi-surface ART restorations have not shown similar results. The aim of this study was to evaluate the survival rate of occluso-proximal ART restorations using two different filling materials: Ketac Molar EasyMix (3M ESPE) and Vitro Molar (DFL). A total of 117 primary molars with occluso-proximal caries lesions were selected in 4 to 8 years old children in Barueri city, Brazil. Only one tooth was selected per child. The subjetcs were randomly allocated in two groups according to the filling material. All treatments were performed following the ART premises and all restorations were evaluated after 2, 6 and 12 months. Restoration survival was evaluated using Kaplan-Meier survival analysis and Log-rank test, while Cox regression analysis was used for testing association with clinical factors (α = 5%). There was no difference in survival rate between the materials tested, (HR = 1.60, CI = 0.98-2.62, p = 0.058). The overall survival rate of restorations was 42.74% and the survival rate per group was Ketac Molar = 50,8% and Vitro Molar G2 = 34.5%). Cox regression test showed no association between the analyzed clinical variables and the success of the restorations. After 12 months evaluation, no difference in the survival rate of ART occluso-proximal restorations was found between tested materials.

  6. One year Survival Rate of Ketac Molar versus Vitro Molar for Occlusoproximal ART Restorations: a RCT

    Directory of Open Access Journals (Sweden)

    PACHECO Anna Luisa de Brito

    2017-11-01

    Full Text Available Abstract Good survival rates for single-surface Atraumatic Restorative Treatment (ART restorations have been reported, while multi-surface ART restorations have not shown similar results. The aim of this study was to evaluate the survival rate of occluso-proximal ART restorations using two different filling materials: Ketac Molar EasyMix (3M ESPE and Vitro Molar (DFL. A total of 117 primary molars with occluso-proximal caries lesions were selected in 4 to 8 years old children in Barueri city, Brazil. Only one tooth was selected per child. The subjetcs were randomly allocated in two groups according to the filling material. All treatments were performed following the ART premises and all restorations were evaluated after 2, 6 and 12 months. Restoration survival was evaluated using Kaplan-Meier survival analysis and Log-rank test, while Cox regression analysis was used for testing association with clinical factors (α = 5%. There was no difference in survival rate between the materials tested, (HR = 1.60, CI = 0.98–2.62, p = 0.058. The overall survival rate of restorations was 42.74% and the survival rate per group was Ketac Molar = 50,8% and Vitro Molar G2 = 34.5%. Cox regression test showed no association between the analyzed clinical variables and the success of the restorations. After 12 months evaluation, no difference in the survival rate of ART occluso-proximal restorations was found between tested materials.

  7. Radiologic study of mandibular third molar of Korean youths

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Hyung Kyu [Dept. of Oral Radiology, College of Dentistry, Seoul National University, Seoul (Korea, Republic of)

    1982-11-15

    The author has made a study on the classification of the mandibular 3rd molars of Korean youths through dental radiography by means of Pell and Gregory's classification and on the prevalence of the dental caries of distal surface of the mandibular 2nd molar adjacent to the mandibular 3rd molars turned anteriorly. The results are as follow; 1. It was found that the largest case number was class I (272 cases, 52.9%) in the relation of the tooth to the ramus of the mandible and 2nd molar. 2. The mesio-angular position was the largest number (239 cases, 46.5%) in the relation of the long axis of the impacted mandibular 3rd molar to the long axis of the 2nd molar. 3. The mesio-angular position of class I was the largest number (140 cases, 27.2%) in the relation of the tooth to the ramus of the mandible and 2nd molar and the long axis of the impacted mandibular 3rd moral to the long axis of the 2nd molar. 4. The average angle of the long axis of mandibular 3rd molar in mesioangular position or horizontal position to the occlusal plane was 143 W 5. Mandibular 3rd molar with lesion such as dental cries or pericoronitis was 73 cases (14.2). 6. The caries incidence rate of the distal surface of the 2nd molar was about 3.1%.

  8. UNILATERAL DISTALIZATION OF MAXILLARY MOLAR BY PENDULUM APPLIANCE

    Directory of Open Access Journals (Sweden)

    Safra Mauna

    2006-04-01

    Full Text Available Pendulum appliance is one of intraoral appliances to distalize molars for correction of class II molar relationship or space gaining in the maxillary arch. Its major advantages are: no need to depend on patient compliance; ease of fabrication; and better patient acceptance. In this case, 22 years old female patient with class II division 2 malocclusion was treated with pendulum appliance for unilateral distalization of the maxillary molar teeth. Pendulum can distalize second molar until 4 mm in 4 months and continues to distalize first molar in 3 months. Nevertheless, relapse 2 mm happens during anterior retraction. This case has shown that pendulum is an effective and reliable appliance for distalizing maxillary molars. However, molar distalization is at the expense of moderate anchorage loss during anterior retraction, which could possibly be reduced if the anchor unit is adequately reinforced.

  9. Bilateral lower second molar impaction in teenagers: An emergent problem?

    Directory of Open Access Journals (Sweden)

    Shinohara Elio

    2010-01-01

    Full Text Available The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impacted third molar for the eruption of the second molar through a vestibular incision. This incision offers excellent bone exposure and exit route for the third molar without disturbing the gingiva attached architecture on the distal face of the first molar providing good healing environment.

  10. Bilateral lower second molar impaction in teenagers: an emergent problem?

    Science.gov (United States)

    Shinohara, Elio H; Kaba, Shajadi Carlos Pardo; Pedron, Irineu Gregnanin; Imparato, Jose Carlos Petorossi

    2010-01-01

    The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impacted third molar for the eruption of the second molar through a vestibular incision. This incision offers excellent bone exposure and exit route for the third molar without disturbing the gingiva attached architecture on the distal face of the first molar providing good healing environment.

  11. Severe rhabdomyolysis after excessive bodybuilding.

    Science.gov (United States)

    Finsterer, J; Zuntner, G; Fuchs, M; Weinberger, A

    2007-12-01

    A 46-year-old male subject performed excessive physical exertion during 4-6 h in a studio for body builders during 5 days. He was not practicing sport prior to this training and denied the use of any aiding substances. Despite muscle aching already after 1 day, he continued the exercises. After the last day, he recognized tiredness and cessation of urine production. Two days after discontinuation of the training, a Herpes simplex infection occurred. Because of acute renal failure, he required hemodialysis. There were absent tendon reflexes and creatine kinase (CK) values up to 208 274 U/L (normal: <170 U/L). After 2 weeks, CK had almost normalized and, after 4 weeks, hemodialysis was discontinued. Excessive muscle training may result in severe, hemodialysis-dependent rhabdomyolysis. Triggering factors may be prior low fitness level, viral infection, or subclinical metabolic myopathy.

  12. MANAGEMENT OF MANDIBULAR THIRD MOLAR SURGERY TO PRESERVE PERIODONTAL HEALTH OF SECOND MOLAR

    Directory of Open Access Journals (Sweden)

    Elitsa G. Deliverska

    2017-06-01

    Full Text Available Background: Extraction of impacted third molar violates surrounding soft and bony tissues. Various surgical approaches and surgical technics have an important impact on the periodontal health of the adjacent second molar. Purpose: The aim of this review is to analyse the causes that can affect postoperative periodontal outcomes for the mandibular second molars (LM2 adjacent to the impacted/ semi impacted mandibular third molars (LM3. Material and Methods: Electronic searches were conducted through the MEDLINE (PubMed, Scopus, etc. databases to screen all relevant articles published from inception to April 2017. Results: Different flap techniques had no significant impact on the probing depth reduction or on the clinical attachment level of LM2. Szmyd and paramarginal flap designs may be the most effective in reducing the probing depth after third molar surgery, and the envelope flap may be the least effective. Use of bone substitutes and guided tissue regeneration therapy has been proposed, to eliminate or prevent these periodontal defects, but there is still no consensus on their predictability or clinical benefit. Higher costs and the risk of postoperative inflammatory complications should also be taken into proper account, as with any surgical procedure. “Orthodontic extraction” is indicated for that impacted M3 that present a high risk of postoperative periodontal defects at the distal aspect of adjacent M2. Conclusion: Risk factors associated with bone loss following lower third molar extraction includes age, the direction of the eruption, preoperative bone defects, and resorbtion of the LM2 root surface. Prevention of such periodontal defects continues to challenge clinicians.

  13. Low-enthalpy geothermal resources for electricity production: A demand-side management study for intelligent communities

    DEFF Research Database (Denmark)

    Xydis, George A.; Nanaki, Evanthia A.; Koroneos, Christopher J.

    2013-01-01

    The geological conditions in Greece contributed to the creation of important low-enthalpy geothermal energy resources (LEGERs). The resources are divided into low, medium and high enthalpy, or temperature, based on criteria that are generally based on the energy content of the fluid. LEGERs...... are those sources of the hot water whose temperature is between 25 and 100°C, which are used for heating residences and in the agricultural or industrial sector. The investigation for the exploitation of low-enthalpy geothermal fluids, which began around 1980, intensified in the last two decades. The low......-enthalpy geothermal potential in Greece is rather significant as most of the geothermal fields have been found in regions with favourable developmental conditions, and it seems that they do not present serious environmental or technical exploitation problems. LEGER areas are abundant in Greece, mainly in the eastern...

  14. Computations of Separated High-Enthalpy Hypersonic Flows: Development of RANS and Variable-Resolution PANS Approaches Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the development of a high fidelity computational approach for unsteady calculations of strongly separated non-equilibrium high-enthalpy hypersonic flows....

  15. 10 CFR 904.9 - Excess capacity.

    Science.gov (United States)

    2010-01-01

    ... Marketing § 904.9 Excess capacity. (a) If the Uprating Program results in Excess Capacity, Western shall be entitled to such Excess Capacity to integrate the operation of the Boulder City Area Projects and other... 10 Energy 4 2010-01-01 2010-01-01 false Excess capacity. 904.9 Section 904.9 Energy DEPARTMENT OF...

  16. 12 CFR 925.23 - Excess stock.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Excess stock. 925.23 Section 925.23 Banks and... BANKS Stock Requirements § 925.23 Excess stock. (a) Sale of excess stock. Subject to the restriction in paragraph (b) of this section, a member may purchase excess stock as long as the purchase is approved by the...

  17. Solvation enthalpy and the thermodynamics of hydration of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine

    Energy Technology Data Exchange (ETDEWEB)

    Tome, Luciana I.N.; Jesus, A.J. Lopes [Department of Chemistry, Rua Larga 3004-535, University of Coimbra (Portugal); Esteves de Castro, R.A. [Faculty of Pharmacy, Rua do Norte 3000-295, University of Coimbra (Portugal); Teixeira, M. Helena S.F. [Department of Chemistry, Rua Larga 3004-535, University of Coimbra (Portugal); Canotilho, Joao [Faculty of Pharmacy, Rua do Norte 3000-295, University of Coimbra (Portugal); Eusebio, M. Ermelinda S. [Department of Chemistry, Rua Larga 3004-535, University of Coimbra (Portugal)], E-mail: quierme@ci.uc.pt

    2007-10-15

    The enthalpy of solution of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine in water was determined by calorimetry. The enthalpy of hydration was determined from this quantity and from the enthalpy of sublimation/vaporization presented in another paper by the authors. Considering the solvation process resulting from cavity creation in the solvent and variation of solute conformation transfer steps, the enthalpy corresponding to solute-solvent interaction was estimated. The entropies of solvation and interaction were calculated from the values given for the enthalpies in the present paper and those available for the Gibbs free energies.

  18. ENTHALPY EU PROJECT: ENABLING THE DRYING PROCESS TO SAVE ENERGY AND WATER, REALISING PROCESS EFFICIENCY IN THE DAIRY CHAIN

    Directory of Open Access Journals (Sweden)

    Berta ALVAREZ PENEDO

    2016-11-01

    Full Text Available The EU funded ENTHALPY project aims to significantly reduce the consumption of water and energy in milk powder production to increase efficiency in the dairy production chain. Using a systematic approach, ENTHALPY project focusses on innovations within the post-harvest chain representing the highest energy and water consumption such as RF heating, solar thermal energy, mono-disperse atomising, dryer modelling, inline monitoring, enzymatic cleaning and membrane technology,

  19. Stepwise excavation in a permanent molar

    DEFF Research Database (Denmark)

    Lima, Fernanda Ferruzzi; Pascotto, Renata Corrêa; Benetti, Ana Raquel

    2010-01-01

    The current study presents a 17-year clinical report of stepwise excavation and indirect pulp capping in a lower right first molar, with great dentin destruction and a lack of dentin support of the cusps. At the first appointment, indirect pulp capping with calcium hydroxide and a temporary filling...... with zinc oxide cement were performed to minimize the risk of pulp exposure during excavation. After 45 days, the remaining carious tissue was removed and a restoration with glass-ionomer lining (Vitrebond) and resin composite (P-50) was performed. Satisfactory morphology and function of the restoration...

  20. Molar Pregnancy Presents as Tubal Ectopic Pregnancy

    Directory of Open Access Journals (Sweden)

    Fatemeh Davari Tanha

    2011-01-01

    Full Text Available Hydatidiform moles are abnormal gestations characterized by the presence of hydropic changesaffecting some or all of the placental villi. Hydatidiform moles arise as a result of the fertilizationof an abnormal ovum. In this report, the patient was a 29 year old Asian woman who had inductionof ovulation with letrozol. Since the majority of molar gestations arise within the uterine cavitythus the occurrence of a hydatidiform mole within ectopic gestational tissue is rare. It is importantto differentiate a hydatidiform mole from a conventional ectopic pregnancy, particularly in infertilewomen who have a history of ovulation induction.

  1. Restorative management of severely ankylosed primary molars.

    Science.gov (United States)

    de Moura, Marcoeli Silva; Pontes, Alessandra Silva; Brito, Maria Hellen Sâmia Fortes; de Deus Moura, Lucia; de Deus Moura de Lima, Marina; de Melo Simplício, Alexandre Henrique

    2015-01-01

    Severe dentoalveolar ankylosis is an etiological factor for malocclusion. When infraocclusion occurs early, it progresses with time, leading to severe consequences in young children because of compensatory supra-eruption of the antagonist tooth and mesialization of adjacent teeth. Early diagnosis allows for interception of the problem and may prevent orthodontic treatment. The purpose of this manuscript is to report two cases of infraocclusion of primary mandibular second molars that were diagnosed early and were treated with composite resin crowns. The use of indirect composite restorations for ankylosed teeth is a good option for primary teeth with a moderate/ severe degree of ankylosis.

  2. Root growth during molar eruption in extant great apes.

    Science.gov (United States)

    Kelley, Jay; Dean, Christopher; Ross, Sasha

    2009-01-01

    While there is gradually accumulating knowledge about molar crown formation and the timing of molar eruption in extant great apes, very little is known about root formation during the eruption process. We measured mandibular first and second molar root lengths in extant great ape osteological specimens that died while either the first or second molars were in the process of erupting. For most specimens, teeth were removed so that root lengths could be measured directly. When this was not possible, roots were measured radiographically. We were particularly interested in the variation in the lengths of first molar roots near the point of gingival emergence, so specimens were divided into early, middle and late phases of eruption based on the number of cusps that showed protein staining, with one or two cusps stained equated with immediate post-gingival emergence. For first molars at this stage, Gorilla has the longest roots, followed by Pongo and Pan. Variation in first molar mesial root lengths at this stage in Gorilla and Pan, which comprise the largest samples, is relatively low and represents no more than a few months of growth in both taxa. Knowledge of root length at first molar emergence permits an assessment of the contribution of root growth toward differences between great apes and humans in the age at first molar emergence. Root growth makes up a greater percentage of the time between birth and first molar emergence in humans than it does in any of the great apes. Copyright (c) 2009 S. Karger AG, Basel.

  3. Taking advantage of an unerupted third molar: a case report.

    Science.gov (United States)

    Pereira, Igor Figueiredo; Santiago, Fernando Zander Mucci; Sette-Dias, Augusto Cesar; Noronha, Vladimir Reimar Augusto de Souza

    2017-01-01

    Treatments with dental surgery seek to displace tooth to the correct position within the dental arch. To report a clinical case that took advantage of an unerupted third molar. A male patient, 18 years of age, was referred by his dentist to evaluate the third molars. The clinical exam revealed no visible lower third molars. The computed tomography (CT) exam showed the presence of a supernumerary tooth in the region of the mandibular ramus, on the left side, and impaction of the third molar, which was causing root resorption on the second molar, thus making it impossible to remain in the buccal cavity. The preferred option, therefore, was to remove both second molar and the supernumerary tooth, in addition to attaching a device to the third molar during surgery for further traction. After 12 months, the third molar reached the proper position. When a mandibular second permanent molar shows an atypical root resorption, an impacted third molar can effectively substitute the tooth by using an appropriate orthodontic-surgical approach.

  4. Molar Incisor Hypomineralization, Prevalence, and Etiology

    Directory of Open Access Journals (Sweden)

    Sulaiman Mohammed Allazzam

    2014-01-01

    Full Text Available Aim. To evaluate the prevalence and possible etiological factors associated with molar incisor hypomineralization (MIH among a group of children in Jeddah, Saudi Arabia. Methods. A group of 8-12-year-old children were recruited (n=267  from the Pediatric Dental Clinics at the Faculty of Dentistry, King Abdulaziz University. Children had at least one first permanent molar (FPM, erupted or partially erupted. Demographic information, children’s medical history, and pregnancy-related data were obtained. The crowns of the FPM and permanent incisors were examined for demarcated opacities, posteruptive breakdown (PEB, atypical restorations, and extracted FPMs. Children were considered to have MIH if one or more FPM with or without involvement of incisors met the diagnostic criteria. Results. MIH showed a prevalence of 8.6%. Demarcated opacities were the most common form. Maxillary central incisors were more affected than mandibular (P=0.01. The condition was more prevalent in children with history of illnesses during the first four years of life including tonsillitis (P=0.001, adenoiditis (P=0.001, asthma (P=0.001, fever (P=0.014, and antibiotics intake (P=0.001. Conclusions. The prevalence of MIH is significantly associated with childhood illnesses during the first four years of life including asthma, adenoid infections, tonsillitis, fever, and antibiotics intake.

  5. Sealing Occlusal Dentin Caries in Permanent Molars

    DEFF Research Database (Denmark)

    Qvist, Vibeke; Borum, Mette Kit; Møller, Kirsten Dynes

    2017-01-01

    The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical and radiog......The purpose of this study was to investigate the possibility of postponing restorative intervention of manifest occlusal caries in young, permanent dentition by non-invasive sealing. This RCT-designed study included 521 occlusal lesions in 521 patients aged 6 to 17 y. Based on clinical...... longevity of sealings and restorations until retreatments, and 3) compare effectiveness of sealings and restorations to halt caries progression in sealed lesions and beneath restorations. Furthermore, we aimed to identify factors influencing longevity and the effectiveness of sealings and restorations.......001). The median survival time for sealings not replaced by restorations was 7.3 y (CI, 6.4 y to NA). Survival of sealings was increased in patients with low caries risk and/or excellent oral hygiene, second molars compared with first molars, and lesions not extending the middle one-third of the dentin. Survival...

  6. Periodontal changes following molar intrusion with miniscrews.

    Science.gov (United States)

    Bayani, Shahin; Heravi, Farzin; Radvar, Mehrdad; Anbiaee, Najmeh; Madani, Azam Sadat

    2015-01-01

    With the introduction of skeletal anchorage system, recently it is possible to successfully intrude molar teeth. On the other hand, there have been concerns about periodontal changes associated with intrusion and there are few studies on this topic, especially for posterior teeth. Ten female patients were enrolled in this study. Maxillary molar intrusion was achieved by inserting two miniscrews and a 17 × 25 titanium molybdenum alloy spring. Crestal height changes were evaluated at three intervals including: Baseline (T0), end of active treatment (T1) and 6 months after retention (T2). Other variables including probing depth, gingival recession, attachment level and bleeding on probing were evaluated by clinical measurements in the three above mentioned intervals. One-sample Kolmogrov-Smirnov test ascertained the normality of the data. For all patients, the changes in tooth position and crestal height were evaluated using one-sample t-test. (P intrusion, but also there were signs of periodontal improvement including attachment gain and shortening of clinical crown height.

  7. Diphoton excess through dark mediators

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chien-Yi [Department of Physics and Astronomy, University of Victoria,Victoria, BC V8P 5C2 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, ON N2J 2W9 (Canada); Lefebvre, Michel [Department of Physics and Astronomy, University of Victoria,Victoria, BC V8P 5C2 (Canada); Pospelov, Maxim [Department of Physics and Astronomy, University of Victoria,Victoria, BC V8P 5C2 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, ON N2J 2W9 (Canada); Zhong, Yi-Ming [C.N. Yang Institute for Theoretical Physics, Stony Brook University,Stony Brook, New York 11794 (United States)

    2016-07-12

    Preliminary ATLAS and CMS results from the first 13 TeV LHC run have encountered an intriguing excess of events in the diphoton channel around the invariant mass of 750 GeV. We investigate a possibility that the current excess is due to a heavy resonance decaying to light metastable states, which in turn give displaced decays to very highly collimated e{sup +}e{sup −} pairs. Such decays may pass the photon selection criteria, and successfully mimic the diphoton events, especially at low counts. We investigate two classes of such models, characterized by the following underlying production and decay chains: gg→S→A{sup ′}A{sup ′}→(e{sup +}e{sup −})(e{sup +}e{sup −}) and qq̄→Z{sup ′}→sa→(e{sup +}e{sup −})(e{sup +}e{sup −}), where at the first step a heavy scalar, S, or vector, Z{sup ′}, resonances are produced that decay to light metastable vectors, A{sup ′}, or (pseudo-)scalars, s and a. Setting the parameters of the models to explain the existing excess, and taking the ATLAS detector geometry into account, we marginalize over the properties of heavy resonances in order to derive the expected lifetimes and couplings of metastable light resonances. We observe that in the case of A{sup ′}, the suggested range of masses and mixing angles ϵ is within reach of several new-generation intensity frontier experiments.

  8. Extrações de molares na Ortodontia Molar extractions in orthodontics

    Directory of Open Access Journals (Sweden)

    Marco Antônio Schroeder

    2011-12-01

    Full Text Available O tratamento ortodôntico com extração de molares em pacientes adultos é tecnicamente mais complexo, devido a inúmeros fatores. Em geral, o espaço a ser fechado é maior do que o espaço dos pré-molares e, por isso, a ancoragem é crítica e o tempo de tratamento mais longo. É comum esses casos apresentarem algum grau de comprometimento periodontal por causa da idade dos pacientes e, portanto, necessitam de maior controle da mecânica ortodôntica para reduzir os efeitos colaterais do fechamento do espaço. Por isso, bons resultados de finalização são mais difíceis de ser alcançados. Sendo assim, este artigo tem como objetivo apresentar as razões para a indicação de extração de molares nos tratamentos ortodônticos, as contraindicações, as diferentes fases da mecânica ortodôntica, esclarecer os fatores envolvidos nesse tipo de planejamento e tratamento e apresentar casos clínicos tratados com extração de molares.Orthodontic treatment with extraction of molars in adult patients is technically more complex due to a number of factors. In general, the space to be closed is greater than premolar spaces rendering critical anchorage and longer treatment time. Often such cases exhibit some degree of periodontal involvement due to patient age. Hence, the need for greater control over orthodontic mechanics to reduce the side effects of space closure. Therefore, good finishing results can be more difficult to achieve. Thus, the purpose of this article is to determine the reasons for molar extraction indications, describe different stages of orthodontic mechanics, and explain the issues involved in this kind of planning and treatment. Additionally, it aims at describing some treatments with molar extractions.

  9. Clinical performance of esthetic posterior crowns in primary molars: a pilot study.

    Science.gov (United States)

    Fuks, A B; Ram, D; Eidelman, E

    1999-01-01

    The aim of this pilot study was to assess the clinical performance of esthetic crowns and to compare these to conventional stainless steel crowns (SSC). Twenty two crowns (11 conventional and 11 esthetic) were placed in mandibular primary molars obeying the following criteria: the tooth was not mobile; no fistulae were present; the tooth had at least one caries free or properly restored antagonist and had to be in contact with one adjacent tooth mesially, in the case of the primary second molars or distally in the case of the primary first molars. Crown preparation was done in a conventional manner, but reduction was more extensive for the thicker esthetic crowns, to allow for proper occlusion. The crowns were evaluated clinically and radiographically after 6 months and the following parameters were assessed: gingival health, marginal extension, crown adequacy, proper position or occlusion, proximal contact, chipping of the facing (for esthetic crowns) and cement removal. At the 6 month evaluation all esthetic crowns were intact, without chipping of the facing, and no excess of cement was observed in both groups. No difference was found for marginal extension, occlusion, proximal contact, crown adequacy, and bone resorption, but a significant difference was found for periodontal health between esthetic crowns and conventional SSC (P crowns assessed had several inconveniences, as they resulted in poor gingival health, are very expensive, and, although not measured, are bulky and without a natural appearance.

  10. Negative βhCG and Molar Pregnancy: The Hook Effect

    Directory of Open Access Journals (Sweden)

    Isabel Lobo Antunes

    2017-09-01

    Full Text Available Molar pregnancy, included in gestational trophoblastic disease, is a benign pathology with ability to metastasize, usually occurring with excessively high βhCG levels. Clinical scenario is usually a woman in extremes of reproductive age presenting with amenorrhoea, pain and vaginal blood loss; signs derived from high βhCG levels may be present (hyperthyroidism, hyperemesis. Diagnosis is based on a positive pregnancy test – usually a qualitative urinary test. The limitation of this test results from its inability to become positive in presence of markedly high levels of βhCG, saturating the antigens used – known as the ‘hook effect’. With the widespread use of gynaecological ultrasound cases of molar pregnancy have been diagnosed in timely fashion. We describe a case referred as a degenerating fibroid, with a negative urinary pregnancy test. Transvaginal ultrasound was highly suggestive of molar pregnancy, which was confirmed with a quantitative βhCG test, allowing for timely treatment. The importance of a high index of suspicion for this pathology is tremendous to avoid the devastating consequences of a delayed diagnosis.

  11. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.

    Science.gov (United States)

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

    2014-11-26

    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Excess Early Mortality in Schizophrenia

    DEFF Research Database (Denmark)

    Laursen, Thomas Munk; Nordentoft, Merete; Mortensen, Preben Bo

    2014-01-01

    Schizophrenia is often referred to as one of the most severe mental disorders, primarily because of the very high mortality rates of those with the disorder. This article reviews the literature on excess early mortality in persons with schizophrenia and suggests reasons for the high mortality...... as well as possible ways to reduce it. Persons with schizophrenia have an exceptionally short life expectancy. High mortality is found in all age groups, resulting in a life expectancy of approximately 20 years below that of the general population. Evidence suggests that persons with schizophrenia may...

  13. Pattern of mandibular third molar impaction and its association to caries in mandibular second molar: A clinical variant.

    Science.gov (United States)

    Prajapati, V K; Mitra, Ruchi; Vinayak, K M

    2017-01-01

    Caries in second molar is common and prophylactic removal of the impacted teeth may be considered appropriate. Caries detection and restoration can be difficult and a restored second molar can undergo recurrent caries if the third molar is not removed prophylactically. In this study, the clinical findings related to impaction and its association with angular position and depth of impacted third molar were evaluated. A retrospective descriptive study was carried out among the patients visiting the outpatient, department of Dentistry, RIMS, Ranchi. The clinical examination, periapical radiographs and Pre-op OPG were taken. Teeth positions were analyzed by Pell and Gregory and Winter classification. The angulation and depth of mandibular third molar impaction and caries in the second molar with the eruption status of the mandibular third molar was determined. A total of 200 patients were included in the study between age group 17-45 years. Majority of the Patients reported to the hospital with complaints of decayed tooth (66%) and pain (59%). The most common third molar impaction was mesioangular followed by distoangular. A statistically highly significant difference (P = 0.001) was obtained with the presence of caries in second molar adjacent to mesioangular third molar in class I and level B. According to this study, pattern of mandibular third molar impaction is in association to caries in mandibular second molar. More future studies are needed. In addition, the results of the present study can be used to screen and inform the patients about the possibility of caries in relation to third molar mandibular impaction.

  14. Survival of sealants in molars affected by molar-incisor hypomineralization: 18-month follow-up.

    Science.gov (United States)

    Fragelli, Camila Maria Bullio; Souza, Juliana Feltrin de; Bussaneli, Diego Girotto; Jeremias, Fabiano; Santos-Pinto, Lourdes Dos; Cordeiro, Rita de Cássia Loiola

    2017-04-27

    The objective of this study was to evaluate the clinical survival of sealants applied in first permanent molars (FPMs) affected by molar-incisor hypomineralization (MIH), at 18 months of follow-up. Forty-one first permanent molars were selected from 21 children, 6-8 years of age. MIH was classified by one calibrated examiner (kappa = 0.80) according to EAPD criteria. The inclusion criteria were fully erupted FPMs with MIH or sound FPMs (without MIH) for which sealant treatment was indicated. The FPMs were assigned to two groups: CG (control group) and HG (MIH group). Both groups were treated with sealant (FluroShield). Clinical follow-up was performed from baseline to 18 months to assess anatomical form, marginal adaptation, retention and presence of caries, according to criteria set by the United States Public Health Service-Modified, and was conducted by a blinded examiner (kappa = 0.80). The actuarial method was used to evaluate the survival of the sealants. The survival rates for the groups were compared using Fisher's exact test (α = 5%). The cumulative survival rates were 81% at 1 month, 68.8% at 6 months, 68.8% at 12 months, and 62.6% at 18 months for CG, and 88% at 1 month, 84% at 6 months, 76% at 12 months, and 72% at 18 months for HG. No significant difference was found between the groups. The sealants in molars affected by MIH presented a survival rate similar to the sealants in the control, suggesting that sealants may be an adequate approach for preventing carious lesions in MIH-affected molars.

  15. Survival of sealants in molars affected by molar-incisor hypomineralization: 18-month follow-up

    Directory of Open Access Journals (Sweden)

    Camila Maria Bullio FRAGELLI

    2017-04-01

    Full Text Available Abstract The objective of this study was to evaluate the clinical survival of sealants applied in first permanent molars (FPMs affected by molar-incisor hypomineralization (MIH, at 18 months of follow-up. Forty-one first permanent molars were selected from 21 children, 6–8 years of age. MIH was classified by one calibrated examiner (kappa = 0.80 according to EAPD criteria. The inclusion criteria were fully erupted FPMs with MIH or sound FPMs (without MIH for which sealant treatment was indicated. The FPMs were assigned to two groups: CG (control group and HG (MIH group. Both groups were treated with sealant (FluroShield. Clinical follow-up was performed from baseline to 18 months to assess anatomical form, marginal adaptation, retention and presence of caries, according to criteria set by the United States Public Health Service-Modified, and was conducted by a blinded examiner (kappa = 0.80. The actuarial method was used to evaluate the survival of the sealants. The survival rates for the groups were compared using Fisher’s exact test (α = 5%. The cumulative survival rates were 81% at 1 month, 68.8% at 6 months, 68.8% at 12 months, and 62.6% at 18 months for CG, and 88% at 1 month, 84% at 6 months, 76% at 12 months, and 72% at 18 months for HG. No significant difference was found between the groups. The sealants in molars affected by MIH presented a survival rate similar to the sealants in the control, suggesting that sealants may be an adequate approach for preventing carious lesions in MIH-affected molars.

  16. Autotransplantation of Mandibular Third Molar: A Case Report

    Directory of Open Access Journals (Sweden)

    Pabbati Ravi kumar

    2012-01-01

    Full Text Available Autogenous transplantation is a feasible, fast, and economical option for the treatment of nonsalvageable teeth when a suitable donor tooth is available. This paper presents successful autotransplantation of a mature mandibular left third molar (38 without anatomical variances is used to replace a mandibular left second molar (37. The mandibular second molar was nonrestorable due to extensive root caries and resorption of distal root. After extraction of mandibular second and third molars, root canal therapy was done for the third molar extraorally, and the tooth was reimplanted into the extracted socket of second molar site. After one year, clinical and radiographic examination revealed satisfactory outcome with no signs or symptoms suggestive of pathology. In selected cases, autogenous tooth transplantation, even after complete root formation of the donor tooth, may be considered as a practical treatment alternative to conventional prosthetic rehabilitation or implant treatment.

  17. Entropy–enthalpy compensation as a fundamental concept and analysis tool for systematical experimental data

    KAUST Repository

    Starikov, E.B.

    2012-06-01

    Enthalpy-entropy compensation (EEC) has a definite physical sense. Here, we review EEC from a new standpoint, using the notion of correlation. The latter has two basic meanings: (a) \\'A\\' is correlated to \\'B\\' means \\'A\\' results from \\'B\\' or vice versa; (b) this same means there is some real, but hidden \\'C\\' in connection to both \\'A\\' and \\'B\\'). In accordance with the interpretation (b), we try rationalizing EEC in terms of hidden, but physically real factors. © 2012 Elsevier B.V. All rights reserved.

  18. Association constants and enthalpies of formation of heteroassociates of anions of cresol red and thymol blue

    Science.gov (United States)

    Shapovalov, S. A.

    2011-01-01

    The tendency of anions of sulfophthaleine dyes to heteroassociation was studied in aqueous solutions of phenol red, cresol red, thymol blue, and non-substituted phenol red. It was spectrophotometrically determined that single (HAn-) and doubly charged anions (An2-) of sulfophthaleines can form stable heteroassociates of the composition Ct+ · HAn- and (Ct+)2 · An2- with cations (Ct+) of polymethine dyes, pinacyanol, and quinaldine red. The values of enthalpy formation of ions of dyes and heteroassociates were calculated semi-empirically and compared with experimentally determined values of the equilibrium association constants.

  19. Free-flight measurement technique in the free-piston high-enthalpy shock tunnel

    Science.gov (United States)

    Tanno, H.; Komuro, T.; Sato, K.; Fujita, K.; Laurence, S. J.

    2014-04-01

    A novel multi-component force-measurement technique has been developed and implemented at the impulse facility JAXA-HIEST, in which the test model is completely unrestrained during the test and thus experiences free-flight conditions for a period on the order of milliseconds. Advantages over conventional free-flight techniques include the complete absence of aerodynamic interference from a model support system and less variation in model position and attitude during the test itself. A miniature on-board data recorder, which was a key technology for this technique, was also developed in order to acquire and store the measured data. The technique was demonstrated in a HIEST wind-tunnel test campaign in which three-component aerodynamic force measurement was performed on a blunted cone of length 316 mm, total mass 19.75 kg, and moment of inertia 0.152 kgm2. During the test campaign, axial force, normal forces, and pitching moment coefficients were obtained at angles of attack from 14° to 32° under two conditions: H0 = 4 MJ/kg, P0 = 14 MPa; and H0 = 16 MJ/kg, P0 = 16 MPa. For the first, low-enthalpy condition, the test flow was considered a perfect gas; measurements were thus directly compared with those obtained in a conventional blow-down wind tunnel (JAXA-HWT2) to evaluate the accuracy of the technique. The second test condition was a high-enthalpy condition in which 85% of the oxygen molecules were expected to be dissociated; high-temperature real-gas effects were therefore evaluated by comparison with results obtained in perfect-gas conditions. The precision of the present measurements was evaluated through an uncertainty analysis, which showed the aerodynamic coefficients in the HIEST low enthalpy test agreeing well with those of JAXA-HWT2. The pitching-moment coefficient, however, showed significant differences between low- and high-enthalpy tests. These differences are thought to result from high-temperature real-gas effects.

  20. A moderate enthalpy and a low pollution load in healthy buildings

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    1998-01-01

    For the design of healthy buildings with a comfortable indoor environment, some general recommendations are provided. New research highlights the importance of controlling the enthalpy of indoor air at a moderate level, i.e., by controlling air temperature and relative humidity at a rather low...... level, still compatible with thermal comfort. A decrement of air temperature or humidity improves the perceived air quality and may decrease the required ventilation rate. A moderate air temperature and humidity plus individual control by radiation and conduction is recommended in order to decrease...

  1. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, January-March 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-04-30

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the third quarter modifications to both the calorimeter and the phase equilibria system were completed. The phase equilibria system was checked out against literature data for methanol/ethanol. Results of these tests are included in this report. The calorimeter was evaluated using previously confirmed heptane data and published data by Thinh, et al. These results are also reported. Initial calorimetry data have been obtained for tetralin and the data will be reported when the data set has been completed. 5 refs., 5 figs., 3 tabs.

  2. Prevalence of eruption status of third molars in Libyan students

    Directory of Open Access Journals (Sweden)

    Sujata Byahatti

    2012-01-01

    Full Text Available Background: The aim of the present study is to determine the number of third molars per person, angulation, level, amount of space for eruption of third molar between ramus of mandible and second molar and the eruption status of third molar in a group of Libyan students, with different impaction patterns and agenesis of third molars. Materials and Methods: In this descriptive retrospective study, a total of 200 students (100 male and 100 female students of bachelor of dental surgery, Faculty of Dentistry, Garyounis University, Benghazi, Libya were enrolled. Students who had complete complement of teeth within the age group 17-26 years were selected for this study, while those cases who had history of extraction of any of the teeth or who refused to give consent were excluded. Before starting the study, ethical concern from the ethical committee, IRB and informed consent from each student who underwent radiography were obtained. Results: The results showed that 5% of third molars were congenitally missing. Approximately 93.5% of the subjects had all four third molars, 1% had two third molars and 0.5% had one third molars with 2.5% having agenesis of all third molars. Third molar agenesis showed predilection for maxilla with higher proportion in females (3% than males (2.1%. Angular position was maximum with vertical position (5.83%, with least being horizontal impactions. Level of occlusal plane of third molar similar to that of adjacent tooth was seen in 44.74%, below the occlusal plane in 24.76%, totally impacted noted in 30%. Conclusion: The present study showed that 33% of the teeth were fully erupted and 66% were in various stages of eruption and 5% were congenitally missing in these students.

  3. Unusal canal configuration in maxillary and mandibular second molars

    Directory of Open Access Journals (Sweden)

    Ramachandran Ragunathan

    2016-01-01

    Full Text Available This clinical article describes three different case reports of maxillary and mandibular second molars with the unusual anatomy of single root with a single canal and their endodontic management. An unusual case of bilateralism is observed in the first two cases in the form of single-rooted second mandibular molars in both the quadrant of the same patient. The presence of maxillary second molar with single root and single canal in the third case is unusual.

  4. Bilateral lower second molar impaction in teenagers: An emergent problem

    OpenAIRE

    Shinohara Elio; Kaba Shajadi; Pedron Irineu; Imparato Jose

    2010-01-01

    The frequency of simultaneously impacted second and third molars in teenagers is increasing and becoming a common occurrence in adolescent oral surgery practice. The traditional treatment is the removal of the third molar by conventional access but repositioning of the surgical flap to the distal face of the first molar can predispose to complications such as pericoronitis and delayed healing of the attached gingiva. We present a case in which we use the germectomy approach to remove the impa...

  5. Intraoperative accidents associated with surgical removal of third molars

    OpenAIRE

    SEBASTIANI,Aline Monise; Todero,Sara Regina Barancelli; Gabardo,Giovana; Costa,Delson João da; Rebelatto,Nelson Luis Barbosa; Scariot, Rafaela

    2014-01-01

    Aim: To evaluate the prevalence of intraoperative accidents associated with extraction of third molars and identify possible risk factors. Methods: Prospective study with patients undergoing third molar surgery by residents of the Oral and Maxillofacial Surgery Service at the Federal University of Parana. Epidemiological data were collected from preoperative evaluation forms. During the surgical procedure were evaluated the radiographic position classifications of all third molars removed, us...

  6. Excessive hoarding in Parkinson's disease.

    Science.gov (United States)

    O'Sullivan, Sean S; Djamshidian, Atbin; Evans, Andrew H; Loane, Clare M; Lees, Andrew J; Lawrence, Andrew D

    2010-06-15

    Hoarding is seen in several psychiatric conditions, but has not been specifically assessed in Parkinson's disease (PD). This study investigates hoarding tendency amongst patients with PD, and its association with impulsive-compulsive spectrum behaviors (ICBs). We compare clinical features, measures of hoarding, impulse buying, self-control, obsessive-compulsive symptoms, depression, and anxiety in 39 patients with PD with ICBs (PD + ICB), 61 patients with PD without ICBs (PD - ICB), and 50 healthy controls. A much higher proportion of PD + ICB (27.8%) than PD - ICB (3.5%) were hoarders (P = 0.001). 6% of healthy controls were hoarders. Compulsive shoppers scored higher than other varieties of ICB on excessive acquisition measures. Hoarding correlated positively with impulsive buying, obsessive-compulsive symptoms, PD duration, and negatively with self-control measures. Using multivariate regression analyzes, the presence of ICBs and measures of impulsive buying were the only variables independently associated with hoarding in PD. The association of hoarding with other ICBs and low trait impulse control suggests that excessive hoarding is related to the spectrum of impulsive behaviors in PD. (c) 2010 Movement Disorder Society.

  7. Second molar impaction associated with lip bumper therapy.

    Science.gov (United States)

    Jacob, Helder Baldi; LeMert, Shawn; Alexander, Richard G; Buschang, Peter H

    2014-01-01

    Although lip bumpers (LBs) provide significant clinical gain of mandibular arch perimeter in mixed-dentition patients, orthodontists are reluctant to use them due to the possibility of permanent second molar eruptive disturbances. The present study was conducted to assess second molar impaction associated with the use of LBs, and to investigate how they can be solved. Lateral and panoramic radiographs of 67 patients (34 females and 33 males) were assessed prior (T₁) and post-LB treatment (T₂). LB therapy lasted for approximately 1.8 ± 0.9 years. Concomitant rapid palatal expansion (RPE) was performed in the maxilla at LB treatment onset. Impaction of mandibular second molars was assessed by means of panoramic radiographs in relation to the position of first mandibular molars. Horizontal and vertical movements of first and second molars were assessed cephalometrically on lateral cephalometric radiographs based on mandibular superimpositions. Eight (11.9%) patients had impacted second molars at the end of LB therapy. Two patients required surgical correction, whereas five required spacers and one patient was self-corrected. Mandibular first molar tip and apex migrated forward 1.3 mm and 2.3 mm, respectively. Second molar tip showed no statistically significant horizontal movement. Although LB therapy increased the risk of second molar impaction, impactions were, in most instances, easily solved.

  8. Second molar impaction associated with lip bumper therapy

    Directory of Open Access Journals (Sweden)

    Helder Baldi Jacob

    2014-12-01

    Full Text Available INTRODUCTION: Although lip bumpers (LBs provide significant clinical gain of mandibular arch perimeter in mixed-dentition patients, orthodontists are reluctant to use them due to the possibility of permanent second molar eruptive disturbances.OBJECTIVE: The present study was conducted to assess second molar impaction associated with the use of LBs, and to investigate how they can be solved.MATERIAL AND METHODS: Lateral and panoramic radiographs of 67 patients (34 females and 33 males were assessed prior (T1 and post-LB treatment (T2. LB therapy lasted for approximately 1.8 ± 0.9 years. Concomitant rapid palatal expansion (RPE was performed in the maxilla at LB treatment onset. Impaction of mandibular second molars was assessed by means of panoramic radiographs in relation to the position of first mandibular molars. Horizontal and vertical movements of first and second molars were assessed cephalometrically on lateral cephalometric radiographs based on mandibular superimpositions.RESULTS: Eight (11.9% patients had impacted second molars at the end of LB therapy. Two patients required surgical correction, whereas five required spacers and one patient was self-corrected. Mandibular first molar tip and apex migrated forward 1.3 mm and 2.3 mm, respectively. Second molar tip showed no statistically significant horizontal movement.CONCLUSION: Although LB therapy increased the risk of second molar impaction, impactions were, in most instances, easily solved.

  9. Epidemiological Status of Third Molars in an Iranian Population

    Directory of Open Access Journals (Sweden)

    Mahnaz Sheikhi

    2016-07-01

    Full Text Available Background Impaction of third molars is a common phenomenon. The incidence of impacted third molars varies in different populations. Objectives The aim of this study is to assess radiographic status (root development degree, angulation, and eruption level of the third molar in Iranian population via panoramic radiographs. Patients and Methods 647 patients, ranging in age from 17 - 25, were selected from three regions of Iran. Based on their panoramic radiographs, their root development degree, angulation, and eruption levels were analyzed. Results The angulation of upper third molars were vertical (44.6%, distoangular (44.1%, mesioangular (10.7%, and horizontal (0.6%. For lower third molars, the angulation was mesioangular (44.5%, vertical (33.8%, distoangular (12.2%, and horizontal (9.5%. The eruption levels of maxillary third molars were C > A> B, and for mandibular third molars they were A > B> C. The order of root development prevalence of the maxillary and mandibular third molars was complete > 2/3 > 1/3. Conclusions The most common status of impaction of the third molars in the maxilla was vertical angulation, level C of eruption, and complete root formation. In the mandible it was mesioangular, level A of eruption, and complete root formation. Since the study sample consists of patients from the north, middle, and south of Iran, the sample can represent the whole population of Iran.

  10. Periodontal Healing Distally to Second Mandibular Molar After Third Molar Coronectomy.

    Science.gov (United States)

    Vignudelli, Elisabetta; Monaco, Giuseppe; Gatto, Maria Rosaria Antonella; Franco, Simonetta; Marchetti, Claudio; Corinaldesi, Giuseppe

    2017-01-01

    Coronectomy of mandibular third molars is a procedure that still raises a number of questions. The aim of the present study was to answer one unsolved question: the periodontal healing distal to the mandibular second molar after third molar coronectomy. A prospective cohort study was performed of 30 patients treated at the Unit of Oral and Maxillofacial Surgery of the Department of Biomedical and Neuromotor Science of the University of Bologna. The predictor variables were the probing pocket depth (PPD), the distance between the marginal crest (MC) and the bottom of the osseous defect (BOD), and the distance between the cementum enamel junction (CEJ) and the BOD. These clinical indexes were recorded on 3 points of the distal surface of second molar: the distobuccal (DB), distomedial (DM), and distolingual (DL) sites. The other variables evaluated included root migration and postoperative complications. The Wilcoxon test for paired data and Kendall's tau-b correlation coefficient was used to evaluate all variables. The significance level was set at P = .05. The cohort was composed of 30 patients with 34 high-risk mandibular third molars (9 men and 21 women), with a mean age of 28 ± 7 years. At 9 months, a statistically significant reduction in the PPD of 2 ± 3, 1 ± 2, and 2 ± 2 mm and a statistically significant reduction in the MC-BOD distance of 4 ± 4, 4 ± 4, and 4 ± 5 mm for the DB, DM, and DL sites, respectively, was observed (P = .001). Also, the intraoperative CEJ-BOD distance showed a statistically significant reduction for the DB, DM, and DL sites. After coronectomy, restoration of a clinical healthy periodontium distal to the second molar was observed. However, further studies are necessary to confirm these preliminary clinical results and to compare periodontal healing between coronectomy and complete extraction. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Second molar periodontal inflammatory disease after third molar removal in young adults.

    Science.gov (United States)

    Dicus, Carolyn; Blakey, George H; Faulk-Eggleston, Jan; Hoverstad, Eric; Offenbacher, Steven; Phillips, Ceib; White, Raymond P

    2010-12-01

    To assess the prevalence of periodontal inflammatory disease on the distal side of second molars after third molar removal and the association between presurgical and surgical variables and postsurgical periodontal outcomes. Data before and after surgery from 2 studies approved by an institutional review board were used. In 1 study, 26 subjects had 4 asymptomatic third molars and in the other 49 subjects had at least 1 mandibular third molar with symptoms of pericoronitis. Full-mouth periodontal probing data, 6 sites per tooth, were obtained as a measurement of periodontal status before and after surgery. A probing depth (PD) ≥4 mm on either of the 2 possible probing sites on the distal side of any second molar (D2M) served as an indicator of periodontal inflammatory disease; periodontal health was defined as all D2M PD <4 mm. Cochran-Mantel-Haenszel row mean score tests compared the subjects' postsurgical periodontal status (all D2M PD <4 mm and at least 1 D2M PD ≥4 mm) with respect to age and time intervals, and the Fisher exact test was used to compare ethnicity, gender, and clinical data at surgery. The McNemar test was used to assess the discordance between subjects' pre- and postsurgical periodontal status. The level of significance was set at .05. Of the 75 subjects, 52% were women and 65% were white. The median age at surgery was 23.6 years (interquartile range, 20.9 to 26.6 years). At enrollment, 53 of 75 subjects (71%) had at least 1 D2M PD ≥4 mm. Subjects were significantly more likely to have an improved D2M periodontal status after surgery than a deteriorated status (P < .01). Fewer subjects, 17 of 75 (24%), had at least 1 D2M PD ≥4 mm after surgery. D2M PD ≥4 mm was more likely after surgery if presurgical D2M was PD ≥4 mm (P < .01). Gender, ethnicity, age, presurgical symptoms, and data estimating the extensiveness of surgery were not significantly associated with postsurgical D2M periodontal outcomes. After third molar removal

  12. Adjacent dentigerous cysts with the ectopic displacement of a third mandibular molar and supernumerary (forth) molar: a rare occurrence.

    Science.gov (United States)

    McCrea, Shane

    2009-06-01

    Dentigerous cysts are the most common odontological cysts of the jaws, being associated with the crowns of permanent teeth, especially unerupted mandibular third molars. Multiple dentigerous cysts are rare and most often occur in association with a developmental syndrome. This article presents an unusual case of nonsyndromic adjacent dentigerous cysts associated with a mandibular third molar and a supernumerary molar. This occurrence has not been previously reported.

  13. Ceramic onlay for endodontically treated mandibular molar

    Directory of Open Access Journals (Sweden)

    Roopadevi Garlapati

    2014-01-01

    Full Text Available Restoration of endodontically treated teeth is important for the success of endodontic treatment. In full coverage restorations, maximum amount of tooth structure is compromised, so as to conserve the amount of tooth structure partial coverage restorations, can be preferred. This case report is on fabrication of a conservative tooth colored restoration for an endodontically treated posterior tooth. A 22-year-old male patient presented with pain in the mandibular left first molar. After endodontic treatment, composite material was used as postendodontic restoration. The tooth was then prepared to receive a ceramic onlay and bonded with self-adhesive universal resin cement. Ceramic onlay restoration was periodically examined up to 2 years.

  14. Vapor pressures and sublimation enthalpies of seven heteroatomic aromatic hydrocarbons measured using the Knudsen effusion technique

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, Jillian L., E-mail: JillianLGoldfarb@gmail.co [Division of Engineering, Brown University, Providence, RI 02912 (United States); Suuberg, Eric M., E-mail: Eric_Suuberg@brown.ed [Division of Engineering, Brown University, Providence, RI 02912 (United States)

    2010-06-15

    The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) g . mol{sup -1} were measured over the temperature range of (301 to 486) K using the isothermal Knudsen effusion technique. The compounds measured include: anthraquinone, 9-fluorenone, 9-fluorenone oxime, phenoxazine, phenoxathiin, and 9H-pyrido[3,4-b]indole. These solid-state sublimation measurements provided values that are compared to vapor pressures of parent aromatic compounds (anthracene and fluorene) and to others with substituent groups in order to examine the effects of alcohol, ketone, pyridine, and pyrrole functionality on this property. The enthalpies and entropies of sublimation for each compound were determined from the Clausius-Clapeyron equation. Though there is no consistent trend in terms of the effects of substitutions on changes in the enthalpy or entropy of sublimation, we note that the prevalence of enthalpic or entropic driving forces on vapor pressure depend on molecule-specific factors and not merely molecular weight of the substituents.

  15. Hydrate thermal dissociation behavior and dissociation enthalpies in methane-carbon dioxide swapping process

    DEFF Research Database (Denmark)

    Mu, Liang; von Solms, Nicolas

    2018-01-01

    The swapping of methane with carbon dioxide in hydrate has been proposed as a potential strategy for geologic sequestration of carbon dioxide and production of methane from natural hydrate deposits. However, this strategy requires a better understanding of the thermodynamic characteristics of CH4...... and CO2 hydrate as well as (CH4 + CO2) or (CH4 + CO2 + N2) mixed hydrates (since (CO2 + N2) gas mixture is often used as the swapping gas), along with the thermal physics property changes during gas exchange. In this study, a high pressure micro-differential scanning calorimetry (HP μ-DSC) was performed...... on synthesized gas hydrates to investigate the dissociation behavior of various hydrates. The hydrate dissociation enthalpies were determined by both μ-DSC measurement and Clapeyron equation. For the single guest molecule hydrate system, the average dissociation enthalpies of CH4 hydrate and CO2 hydrate measured...

  16. Oil presence in an evaporator: experimental validation of a refrigerant/oil mixture enthalpy calculation model

    Energy Technology Data Exchange (ETDEWEB)

    Youbi-Idrissi, M.; Bonjour, J.; Terrier, M.-F.; Meunier, F. [Laboratoire du Froid, Paris Cedex (France); Marvillet, C. [GRETh, CEA Grenoble (France)

    2004-05-01

    In this paper, the impact of the oil presence on the performance of a refrigerating machine is investigated both experimentally and numerically. To highlight the effect of oil, particularly on the evaporator behaviour, a theoretical model of enthalpy calculation for a refrigerant/oil mixture has been previously developed [Int J Refrigeration, 26(2003), 284]. In order to validate this model, tests were carried out on an industrial refrigerating machine working with R-407C. The lubricant is a polyol-ester oil whose solubility curves are given by the oil manufacturer. The oil circulating mass fraction is measured by a sampling technique and by an on-line density measurement method, whose advantages and drawbacks are presented. Both the model and the experiments show that the ratio of enthalpy change through the evaporator with to without the oil presence increases when the apparent superheat at the evaporator outlet increases. This is due to the presence of a non-evaporated amount of liquid refrigerant dissolved in the oil at this location, which is confirmed by visual observations. The numerical and experimental results are found to be in a good agreement as the maximum deviation is about 2.2%. (author)

  17. Absolute ion hydration enthalpies from absolute hardness and some VBT relationships

    Science.gov (United States)

    Kaya, Savaş; Fernandes de Farias, Robson

    2018-01-01

    In the present work, absolute hydration enthalpies are calculated from ion absolute hardness for a series of +1 and -1 ions. The calculated values are compared with those previously reported (Housecroft, 2017) [2] and relationships between Vm-1/3 and absolute hardness are stablished. The following empirical equations have been derived, for cations and anions, respectively: ΔhydHo = -(9.645 η+ + 245.930) and ΔhydHo = -(64.601 η- + 12.321). In such equations, η+ and η- are the absolute hardness. It is shown that for d block monocations (Cu+, Ag+ and Au+), hydration enthalpy is closely related with Clementi effective nuclear charge by the equation: ΔhydHo = -(9.645 η+ + 245.930) (Zeff/(n - 1)), where n is the main quantum number. Furthermore, is shown that a typical VBT parameter (Vm-1/3) is related with η+ and η- values and so, with the energies of the frontier orbitals, that is, is stablished a direct relationship between a structural parameter available by X-ray data and the energy of atomic/molecular orbitals.

  18. High precision calorimetry to determine the enthalpy of combustion of methane

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Andrew; Lythall, Christopher; Aucott, John; Sayer, Courtnay [Office of Gas and Electricity Markets, Technical Directorate, 3 Tigers Road, South Wigston, LE18 4UX Leicester (United Kingdom)

    2002-01-31

    The enthalpy of combustion of methane is the most important property used in the determination of the calorific value of natural gas. Only two sets of values with high accuracy and precision and measured under appropriate conditions have been published since it was first determined in 1848. These studies were done by Rossini, at the National Bureau of Standards in the USA in 1931, and Pittam and Pilcher, at the University of Manchester in 1972. This report details the design and operation of a high precision constant-pressure gas burning calorimeter, based on the design of those used in the previous studies, to measure the superior enthalpy of combustion of ultra-high purity methane at 25C.The use of modern equipment and automatic data collection leads to a value, traceable to national standards, of 890.61kJmol{sup -1} with a combined standard uncertainty of 0.21kJmol{sup -1}. This is in full accord with the value of 890.63kJmol{sup -1} calculated from the average of Rossini's and Pittam and Pilcher's work (with a random uncertainty based on 1 S.D. of 0.53kJmol{sup -1})

  19. Adsorption sites, adsorption enthalpies and potential removal of terpenoids by atmospheric ice

    Science.gov (United States)

    Czech, Christian; Hammer, Sonja M.; Bonn, Boris; Schmidt, Martin U.

    2011-01-01

    Ice crystal formation and its effect on atmospheric trace gases are currently an important area of research because of its radiation and climate effects. However, the processes of adsorption of trace gases on ice surfaces and absorption into ice crystals are poorly understood. Both processes are investigated by lattice-energy minimisation for a selected number of atmospherically relevant volatile organic compounds, i.e. isoprene, methacrolein, acetone, methylbutenol, perillyl alcohol and 2,10-pinanediol, which can be considered as exemplary substances for similar structured compounds. Adsorption and absorption geometries and enthalpies are computed and the potential uptake strength is approximated. According to our calculations non-polar terpenes like isoprene are not significantly adsorbed by ice crystals. Oxidized terpenoids have stronger interactions with the ice surface (at least two hydrogen bonds) leading to larger adsorption enthalpies. Absorption into the ice crystal plays only a minor role. Correspondingly, in the atmosphere terpenoid compounds are increasingly adsorbed to ice surfaces with increasing oxygen numbers. Subsequently this process can contribute to the wet removal of terpenoids by ice, which is so far ignored in global transport models.

  20. Enthalpy measurement of coal-derived liquids. Technical progress report, August-October 1982

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1982-11-30

    The correlational effort on the coal syncrudes and model compounds has been proceeding along two fronts. The first involves experimental work on a correlating factor for association in the liquids and the second involves an investigation of the modeling capabilities of cubic equations of state. The first area of investigation is the experimental measurement of a correlating factor for assocition in coal liquids. The procedure involves molecular weight measurement by freezing point depression. To facilitate these measurements, a simple Beckman freezing point depression apparatus is being currently modified to increase the accuracy, speed, and ease of measurement. The second area of effort has involved establishing a set of cubic equations of state which can adequately model the enthalpy departures of quinoline and m-cresol. To this effort, a number of standard and association specific equations of state have been tested against a data base of previously measured enthalpy departures of m-cresol and quinoline. It has been found that these equations do quantitatively a poor job on m-cresol and quinoline. These problems are probably due to the highly polar nature of m-cresol and to a lesser extent quinoline, and to the poor quality of critical parameters for quinoline.

  1. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, October-December 1984

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1985-01-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the second quarter efforts were limited to ordering and installing equipment to improve the operability of the calorimeter and phase behavior system. The program is now up to full staffing levels and data collection will begin this next quarter. The objectives of this program are to study the enthalpy and phase behavior of a selected ternary model compound system, representative of interactions present in coal derived liquids. Measurements will be made in a Freon 11 reference fluid boil off calorimeter, and an equilibrium flash vaporization apparatus. These experimental systems have already been developed. Previous studies have indicated that existing data and correlations developed for petroleum fluids are not applicable to coal derived liquids. This is due to the presence of significant concentrations of polar associating heteroatomics in the predominantly aromatic coal liquids. Thus, the ternary system will include an aromatic, a basic nitrogen compound, and a cresol. It is presently planned to study the tetralin/quinoline/m-cresol ternary mixture. Measurements will be made over a wide range of temperature (200 to 700/sup 0/C) and pressure (20 to 1500 psia), for the three pure compounds.

  2. Enthalpy and phase behavior of coal derived liquid mixtures. Technical progress report, October-December 1985

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1986-01-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the sixth quarter, preliminary enthalpy measurements for the 1/3:2/3, 1/2:1/2, 2/3:1/3 m-cresol tetralin binary mixtures have been completed and are included in a section at the end of this report. Vapor liquid equilibria measurements for the m-cresol/tetralin system are in progress for four isotherms. Tetralin vapor pressures are reported in this report from both the VLE apparatus and the calorimeter. In addition, ongoing research into the modeling of polar systems has led to an approach for modifying the Soave equation of state. This equation of state introduces a polar parameter which appears to be related to the expected strength of polar interactions for different compounds. The appendix contains the paper on this work titled ''Approach for extending Van de Waals equations of state for polar, hydrogen bonding fluids applied to the Soave equation of state''. This article has been processed separately for inclusion in the Energy Data Base.

  3. The available-enthalpy (flow-exergy) cycle. Part-II: applications to idealized baroclinic waves

    CERN Document Server

    Marquet, Pascal

    2014-01-01

    The local available-enthalpy cycle proposed in Part I of this paper is applied to document energetics of three numerical simulations, representing life cycles of idealized baroclinic waves. An improved temporal numerical scheme defined in Part I is used in this study, together with the Arpege-IFS model using a T42 triangular truncation. A 45{\\deg}N and 200 hPa dry unstable jet is constructed with the most unstable mode at zonal wave number 8. Energetic impacts of both horizontal and vertical diffusion schemes are determined separately. The role of ageostrophic winds within the Ekman layer is investigated, leading to an explanation for large observed values for the dissipation terms and to a new formulation of the potential-energy conversions. The magnitudes of these new conversion terms are compared with those of the usual barotropic and baroclinic conversions. A new version for the available-enthalpy cycle is proposed. It is suitable for open systems and it includes explicitly the potential-energy component ...

  4. The effects of excessive humidity.

    Science.gov (United States)

    Williams, R B

    1998-06-01

    Humidification devices and techniques can expose the airway mucosa to a wide range of gas temperatures and humidities, some of which are excessive and may cause injury. Humidified gas is a carrier of both water and energy. The volume of water in the gas stream depends on whether the water is in a molecular form (vapor), particulate form (aerosol), or bulk form (liquid). The energy content of gas stream is the sum of the sensible heat (temperature) of the air and any water droplets in it and the heat of vaporization (latent energy) of any water vapor present. Latent heat energy is much larger than sensible heat energy, so saturated air contains much more energy than dry air. Thus every breath contains a water volume and energy (thermal) challenge to the airway mucosa. When the challenge exceeds the homeostatic mechanisms airway dysfunction begins, starting at the cellular and secretion level and progressing to whole airway function. A large challenge will result in quick progression of dysfunction. Early dysfunction is generally reversible, however, so large challenges with short exposure times may not cause irreversible injury. The mechanisms of airway injury owing to excess water are not well studied. The observation of its effects lends itself to some general conclusions, however. Alterations in the ventilation-perfusion ratio, decrease in vital capacity and compilance, and atelectasis are suggestive of partial or full occlusion of small airways. Changes in surface tension and alveolar-arterial oxygen gradient are consistent with flooding of alveoli. There also may be osmotic challenges to mucosal cell function as evidenced by the different reaction rates with hyper- and hypotonic saline. The reaction to nonisotonic saline also may partly explain increases in specific airway resistance. Aerosolized water and instilled water may be hazardous because of their demonstrated potential for delivering excessive water to the airway. Their use for airway humidification or

  5. Presence of third molars in orthodontic patients from northern Greece

    Directory of Open Access Journals (Sweden)

    Barka G

    2012-05-01

    Full Text Available Georgia Barka,1 Georgios Tretiakov,1 Theodosios Theodosiou,2 Ioulia Ioannidou-Marathiotou31School of Dentistry, 2Biostatistics, Department of Informatics, School of Natural Sciences, 3Department of Orthodontics, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, GreeceObjective: The purpose of the present study was to investigate the frequency of presence of third molar teeth and their distribution in each jaw and each side, according to sex, in a group of orthodontic patients with permanent dentition from northern Greece.Methods: The sample included panoramic radiographs from 220 patients with permanent dentition (mean age 13.62 ± 1.81. The Χ2 test was used to assess the relationships between the variables, and the Fisher's exact test was used in cases where the expected frequencies in each cell were <5.Results: The frequency of third molar presence was 79.1%, and 20.9% was the frequency of third molar agenesis. Intersexual differences in the number of third molars was not statistically significant. There was a correlation between the distribution of third molars on the right and the left side (Fisher's exact test = 100.788; P = 0. The two sides showed the same tendency toward the presence or absence of third molars. A correlation was also found between the distribution of maxillary and mandibular third molars (Fisher's exact test = 24.372; P = 0. In each jaw, the presence or absence of third molars was highly related to the number of third molars found in the other jaw.Conclusion: The present results showed that in this orthodontic group of northern Greek patients, presence accounted for 79.1% and agenesis for 20.9%. No significant difference was found between the frequencies of third molar presence on the left and right sides in either the maxilla or mandible.Keywords: third molars, presence, orthodontic population, Greeks

  6. 10 CFR 904.10 - Excess energy.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Excess energy. 904.10 Section 904.10 Energy DEPARTMENT OF ENERGY GENERAL REGULATIONS FOR THE CHARGES FOR THE SALE OF POWER FROM THE BOULDER CANYON PROJECT Power Marketing § 904.10 Excess energy. (a) If excess Energy is determined by the United States to be available...

  7. 7 CFR 985.56 - Excess oil.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Excess oil. 985.56 Section 985.56 Agriculture... HANDLING OF SPEARMINT OIL PRODUCED IN THE FAR WEST Order Regulating Handling Volume Limitations § 985.56 Excess oil. Oil of any class in excess of a producer's applicable annual allotment shall be identified as...

  8. 43 CFR 426.12 - Excess land.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Excess land. 426.12 Section 426.12 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR ACREAGE LIMITATION RULES AND REGULATIONS § 426.12 Excess land. (a) The process of designating excess and...

  9. Excess water dynamics in hydrotalcite: QENS study

    Indian Academy of Sciences (India)

    Abstract. Results of the quasi-elastic neutron scattering (QENS) measurements on the dynamics of excess water in hydrotalcite sample with varied content of excess water are reported. Translational motion of excess water can be best described by random transla- tional jump diffusion model. The observed increase in ...

  10. Shear bond strength evaluation of bonded molar tubes on fluorotic molars.

    Science.gov (United States)

    Silva-Benítez, Erika L; Zavala-Alonso, Veronica; Martinez-Castanon, Gabriel A; Loyola-Rodriguez, Juan P; Patiño-Marin, Nuria; Ortega-Pedrajo, Irene; García-Godoy, Franklin

    2013-01-01

    To study the shear bond strength (SBS), sites of failure, and micromorphology of bonded molar tubes used on teeth affected by dental fluorosis. This in vitro study included 140 first molars classified according to Dean's index for dental fluorosis. Samples were divided into seven groups: (1) healthy teeth etched for 15 seconds, (2) teeth with moderate fluorosis (MOF) etched for 15 seconds, (3) teeth with MOF etched for 150 seconds, (4) teeth with MOF microabrasion etched for 15 seconds, (5) teeth with severe fluorosis (SEF) etched for 15 seconds, (6) teeth with SEF etched for 150 seconds, and (7) teeth with SEF microabrasion etched for 15 seconds. All samples were incubated and were then submitted to the SBS test and evaluated with the modified adhesive remnant index (ARI) and analyzed by using a scanning electronic microscope. The SBS mean value for healthy enamel was 20 ± 10.2 MPa. For the group with MOF, the etched 150-second mean value was the highest (19 ± 7.6 MPa); for the group with SEF treated with microabrasion and etched for 15 seconds, the mean value was (13 ± 4.1 MPa). Significant differences (P ≤ .05) were found in the ARI between healthy and fluorosed groups. Fluorotic enamel affects the adhesion of bonded molar tubes. The use of overetching in cases of MOF and the combination of microabrasion and etching in SEF provides a suitable adhesion for fixed appliance therapy.

  11. Histomorphometric evaluation of maxillary molar roots and surrounding periodontium following molar intrusion in rats.

    Science.gov (United States)

    Choi, Y J; Kim, K H; Lee, K J; Chung, C J; Park, Y C

    2015-02-01

    To investigate periodontal tissue changes during and after molar intrusion in rats. The Department of Orthodontics at Yonsei University. Thirty 12-week-old male rats were assigned to 1 control and 5 experimental groups (n = 5 each). In the experimental groups, two maxillary molars were intruded for 2 weeks; the control group underwent the same procedures without the intrusion force. After 2 weeks of intrusion, rats in one of the experimental groups and in the control group were killed. In the other four experimental groups, the new molar positions were either retained or not retained with an occlusal bite block for 1 or 2 weeks prior to euthanization. Histomorphometric analysis was performed for sulcus depth, osteoclast number per unit alveolar bone length, and root resorption area per unit root surface length. Sulcus depth increased during intrusion (P intrusion (P intrusion, irrespective of the retention regimen, relative to that of the control group (P intrusion and that the surrounding periodontium remodeled accordingly as tooth positions were altered, regardless of retention regime. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Interspecific and intraspecific variation in selenium:mercury molar ratios in saltwater fish from the Aleutians: Potential protection on mercury toxicity by selenium

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael; Jeitner, Christian; Donio, Mark; Pittfield, Taryn

    2014-01-01

    A number of factors affect the consumption risk from mercury in fish, including mercury levels, seasonal patterns of mercury concentrations, human consumption patterns, and sensitive populations (e.g. pregnant women, fetuses, young children, and yet unknown genetic factors). Recently the protective effects of selenium on methylmercury toxicity have been publicized, particularly for saltwater fish. We examine levels of mercury and selenium in several species of fish and seabirds from the Aleutians (Alaska), determine selenium:mercury molar ratios, and examine species-specific and individual variation in the ratios as a means of exploring the use of the ratio in risk assessment and risk management. Variation among species was similar for mercury and selenium. There was significant inter-specific and intraspecific variation in selenium:mercury molar ratios for fish, and for birds. The mean selenium:mercury molar ratios for all fish and bird species were above 1, meaning there was an excess of selenium relative to mercury. It has been suggested that an excess of selenium confers some protective advantage for salt water fish, although the degree of excess necessary is unclear. The selenium:mercury molar ratio was significantly correlated negatively with total length for most fish species, but not for dolly varden. Some individuals of Pacific cod, yellow irish lord, rock greenling, Pacific halibut, dolly varden, and to a lesser extent, flathead sole, had selenium:mercury ratios below 1. No bird muscle had an excess of mercury (ratio below 1), and only glaucous-winged gull and pigeon guillemot had ratios between 1 and 5. There was a great deal of variation in selenium:mercury molar ratios within fish species, and within bird species, making it difficult and impractical to use these ratios in risk assessment or management, for fish advisories, or for consumers, particularly given the difficulty of interpreting the ratios. PMID:22664537

  13. An audit of impacted mandibular third molar surgery | Obimakinde ...

    African Journals Online (AJOL)

    Methodology: We carried out a descriptive clinical study involving patients who presented for management of impacted third molar between January 2010 and December 2011. Demography of the patients including third molar spatial relationship, indications for surgery and pre- and post-operative visual analogue score for ...

  14. Internal root morphology in maxillary first permanent molars in a ...

    African Journals Online (AJOL)

    Objective: To determine the internal root morphology and gender variations in maxillary first permanent molars in a Kenyan population. Design: In vitro descriptive cross-sectional study. Setting: School of Dental Sciences, University of Nairobi. Subject: One hundred and eighty seven maxillary first permanent molars were ...

  15. Incomplete molar pregnancy with live coexisting fetus: a case report

    Directory of Open Access Journals (Sweden)

    Leila Pourali

    2014-03-01

    Conclusion: The rate of pregnancy complications such as hypertension, hyperthyroidism, and obstetrics hemorrhage and also the risk of Gestational Trophoblastic Neoplasm (GTN are increasing in incomplete molar pregnancy. Therefore, early diagnosis and timely treatment of molar pregnancy is very important to reduce maternal morbidity and mortality.

  16. Case report - Ectopic molar pregnancy: A case report | Bousfiha ...

    African Journals Online (AJOL)

    The incidence of hydatidiform moles is 1 per 1,000 pregnancies. Ectopic pregnancy occurs in 20 per 1,000 pregnancies. Thus, the incidence of the ectopic molar gestation is very rare. We report a case of tubal molar pregnancy diagnosed at the systematic histology exam of an ectopic pregnancy. We report the case of 32 ...

  17. Evaluation of radiographic features of embedded primary molar ...

    African Journals Online (AJOL)

    Background: The roots of primary molars were found in the permanent dentition without symptoms on the clinical or radiographic examination. However, their incidence could not be achieved on the current literature. Objective: The aim of this study is to evaluate the radiographic features of the embedded primary molar roots ...

  18. Impacted Mandibular Third Molars: Review of Literature and a ...

    African Journals Online (AJOL)

    impacted mandibular third molar surgery: 1‑year results. Int. J Periodontics Restorative Dent 1993;13:397. 43. Edwards MJ, Brickley MR, Goodey RD, Shepherd JP. The cost, effectiveness and cost effectiveness of removal and retention of asymptomatic, disease free third molars. Br Dent. J 1999;187:380‑4. 44. Smith WP.

  19. [Supernumerary teeth located in molar region: three cases report].

    Science.gov (United States)

    Dai, Jie; Yang, Weijiang; Shen, Xuanjiang

    2011-08-01

    Supernumerary teeth is one of the teeth dysplasia that the number of teeth exceeded normal. Most of supernumerary teeth reported were located in anterior teeth region, but rare cases were reported in molar region. This paper reported three cases that supernumerary teeth located in molar region.

  20. Molar incisor hypomineralisation: clinical management of the young patient.

    LENUS (Irish Health Repository)

    Daly, Dympna

    2009-04-01

    Molar incisor hypomineralisation (MIH) is a common developmental condition resulting in enamel defects in first permanent molars and permanent incisors. It presents at eruption of these teeth. Early diagnosis is essential since rapid breakdown of tooth structure may occur, giving rise to acute symptoms and complicated treatment. The purpose of this article is to review MIH and illustrate its clinical management in young children.

  1. Changes in heart rate during third molar surgery

    NARCIS (Netherlands)

    Hollander, M. H. J.; Schortinghuis, J.; Vissink, A.

    2016-01-01

    Anxiety is an undesirable psychological phenomenon. Patients are usually anxious when subjected to third molar surgery, but the pattern of anxiety is unknown. The aim of this study was to assess the intensity and course of anxiety during third molar surgery. This study included 48 consecutive

  2. Variant root morphology of third mandibular molar in normal and ...

    African Journals Online (AJOL)

    Variant root morphology of third mandibular molar in normal and impacted teeth. Isaac Kipyator Bokindo, Fawzia Butt, Francis Macigo. Abstract. The mandibular third molar poses a challenge to dental surgeons due to it's unpredictable morphology which leads to increased difficulty during its extraction. The root morphology ...

  3. Fatigue resistance of CAD/CAM resin composite molar crowns.

    NARCIS (Netherlands)

    Shembish, F.A.; Tong, H.; Kaizer, M.; Janal, M.N.; Thompson, V.P.; Opdam, N.J.M.; Zhang, Y.

    2016-01-01

    OBJECTIVE: To demonstrate the fatigue behavior of CAD/CAM resin composite molar crowns using a mouth-motion step-stress fatigue test. Monolithic leucite-reinforced glass-ceramic crowns were used as a reference. METHODS: Fully anatomically shaped monolithic resin composite molar crowns (Lava

  4. Indications and risk factors for complications of lower third molar ...

    African Journals Online (AJOL)

    Aim: The aim of this study was to determine the surgical indications and risk factors for complications of third molar surgery at a Nigerian teaching hospital. ... records of patients referred to the Oral Surgery Clinic of our institution for surgical extraction of their impacted mandibular third molars from January 2008 to December ...

  5. Impacted Mandibular Third Molars: Review of Literature and a ...

    African Journals Online (AJOL)

    Keywords like impaction, mandibular third molar, impacted mandibular third molar, complications, anatomy, inferior alveolar nerve injury, lingual nerve injury were used to search the databases. A total of 826 articles were screened, and 50 articles were included in the review which was obtained from 1980 to February 2015.

  6. Prematurely erupted tooth in the molar region | Denloye | Nigerian ...

    African Journals Online (AJOL)

    This paper reports the case of a thirty-three-day old male child who was seen at the outpatient clinic of the University College Hospital, Ibadan with a tooth- like structure in the maxillary right molar region. This firm structure which resembled a primary molar had only two definite buccal cusps, no lingual cusp and no occlusal ...

  7. Pathomorphology of Molar Gestation in Zaria | Mayun | Nigerian ...

    African Journals Online (AJOL)

    Background: Molar gestations are a source of significant morbidity with increased risk of mortality from their complications if not identified and treated early enough. Objective: This study aims at histologically reviewing and analyzing all cases of molar gestations seen in the Histopathology Department of Ahmadu Bello ...

  8. Internal root morphology in mandibular first permanent molars in a ...

    African Journals Online (AJOL)

    Objective: To determine the internal root morphology and gender variations in mandibular first permanent molars in a Kenyan population. Design: In vitro descriptive cross sectional study. Setting: School of Dental Sciences, University of Nairobi Results: The mesial root of mandibular first molars had two canals in 96.3% of ...

  9. Molar pregnancy: a ten year review at Onitsha, Nigeria | Obiechina ...

    African Journals Online (AJOL)

    The incidence of molar pregnancy was 1:332 deliveries or 1.416 pregnancies. There was no definite age pattern in the distribution of molar pregnancy. The commonest clinical presentation was recurrent vaginal bleeding 90.6% while the least was uterine size less than date in 3.8% of the cases. Syntocinon induction with ...

  10. [Clinical analysis of caries status of the mandibular second molar].

    Science.gov (United States)

    You, Chun-an; Zheng, Ping; Hu, Ning; Su, Qin

    2014-04-01

    To collect the cases which have caries on the mandibular second molar and analyze the caries status and correlative factors. Patients treated in the Department of Endodontics in West China Hospital of Stomatology were randomly collected. The baseline information, primary sites and severity of dental caries on the mandibular second molar, and eruption pattern of the mandibular third molar were recorded. The data was analyzed with SPSS13.0 software package. Four hundred eighty-one patients including 227 males and 254 females were collected. Caries on the mandibular second molar starting from the occlusal, distal proximal and buccal surfaces accounted for 33.8%, 33.2% and 24.4%, respectively. Caries involving dental pulp (49.7%) were significantly more than deep and shallow to moderate caries (31.7% and 18.6%). Gender was not correlated with the site and severity of caries. However, impacted mandibular third molars and age were significantly related to both caries site and severity. Occlusal and distal proximal surfaces are the most predisposed sites to have caries on mandibular second molar. Impacted mandibular third molar and age are significantly related to caries of mandibular second molar.

  11. Prevalent of root resorption of second molar adjustment the impacted third molar in prepiacal and panoramic radiographs

    Directory of Open Access Journals (Sweden)

    Mohammad Ebrahimi Saravi

    2013-10-01

    Full Text Available   Background and Aims: Impacted third molar reduces the bone level in the distal aspect of second molar, and sometimes it can lead to root resorption of the adjacent tooth. The purpose of this study was to determine this resorption using panoramic and periapical radiographs.   Materials and Methods: In this cross-sectional descriptive study 54 patient (28 men, 26 women above 15 years old with the average of 22 years in Oral and Maxillofacial Department of Tehran University were studied. A periapical radiography from the third molar and a panoramic radiograph were taken from each patient (Because of their routine use and evaluation of accuracy of panoramic compared with periapical, and the magnitude of the root resorption for the second molar was determined by 2 observers and written in a questionnaire. Data were analyzed using Fisher test.   Results: The prevalence of the root resorption of the second molar adjacent to the impacted third molar in the panoramic and the periapical radiographies, with respect to the limitation of the sample size were 46.3% and 31.5%, respectively, with 95% confidence(P>0.05. Most of these resorptions were in the cervical third of the second molar roots and in cases in which the third molars were mesially oriented or horizontal. There was also no significant difference between panoramic and periapical radiographs.   Conclusion: Due to the increased risk of the resorption of the second molar adjacent to the third molar, extraction of the impacted third molars, especiall y mesially oriented or horizontal ones are recommended.

  12. Pulpotomies with portland cement in human primary molars

    Directory of Open Access Journals (Sweden)

    Taísa Regina Conti

    2009-02-01

    Full Text Available Two clinical cases in which Portland cement (PC was applied as a medicament after pulpotomy of mandibular primary molars in children are presented. Pulpotomy using PC was carried out in two mandibular first molars and one mandibular second molar, which were further followed-up. At the 3, 6 and 12-month follow-up appointments, clinical and radiographic examinations of the pulpotomized teeth and their periradicular area revealed that the treatments were successful in maintaining the teeth asymptomatic and preserving pulpal vitality. Additionally, the formation of a dentin bridge immediately below the PC could be observed in the three molars treated. PC may be considered as an effective alternative for primary molar pulpotomies, at least in a short-term period. Randomized clinical trials with human teeth are required in order to determine the suitability of PC before unlimited clinical use can be recommended.

  13. Enthalpy measurement of coal-derived liquids. Quarterly technical progress report, July-September, 1978. [148 to 459/sup 0/F; 100 to 300 psia

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1978-12-01

    Experimental measurements were completed on a naphtha sample (1046) furnished by the Pittsburg and Midway Coal Mining Company. A total of 38 measurements were made in the temperature region 148 to 459/sup 0/F, and at pressures of 100 and 300 psia. Additional analytical work was also completed on the SRC-I naphtha whose enthalpy measurements were reported in previous progress reports. Comparisons are given between the experimental SRC-I naphtha enthalpies and the available petroleum enthalpy correlations.

  14. Enthalpies of the reaction of N-methylpyrrolidone with C/sub 9/-C/sub 12/ arenes

    Energy Technology Data Exchange (ETDEWEB)

    Yanbukhtina, R.A.; Gaile, A.A.; Semenov, L.V.

    1988-07-20

    Mixing of N-methylpyrrolidone with monocycloaromatic hydrocarbons takes place with an endothermic effect and mixing with bicycloaromatic hydrocarbons occurs with an exothermic effect. This is due to an increase in the proportion of the specific reaction in going from systems with mono- and bicycloaromatic hydrocarbons from 30 to 50-60% of the total enthalpy of the reaction. The enthalpies of the specific reaction of arenes with N-methylpyrrolidone are correlated with the donor numbers of the hydrocarbons. The difference in the enthalpies of solvation of saturated and aromatic hydrocarbons by N-methylpyrrolidone is greater than with dimethylformamide and furfural, which is in agreement with the higher selectivity of N-methylpyrrolidone.

  15. Enthalpies of solution of tetramethyl-bis-urea (Mebicarum) in amides and acetone at 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Evgeniy V. [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Str., 153045 Ivanovo (Russian Federation)], E-mail: evi@isc-ras.ru; Abrosimov, Vladimir K.; Smirnov, Valeriy I. [Laboratory of Thermodynamics of Solutions of Non-electrolytes and Biologically Active Substances, Institute of Solution Chemistry, Russian Academy of Sciences, 1 Akademicheskaya Str., 153045 Ivanovo (Russian Federation)

    2007-10-25

    The enthalpies of solution of 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione or tetramethyl-bis-urea (the drug Mebicarum) in formamide, N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, N,N,N',N'-tetramethylurea, and acetone were measured at 298.15 K. Standard enthalpies of solution and transfer from one solvent to another were computed. The enthalpies of solution of the solute were found to be endothermic and weak depending on the nature of methylation in an amide molecule. It was concluded that the solvent proton-donor ability and existing steric hindrances for H-bonding and other interparticle interactions play the key role in solvation of tetramethyl-bis-urea.

  16. Enthalpy and phase behavior of coal derived liquid mixtures: Technical progress report for the period July-September 1987

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1987-10-31

    The objectives of this program are to study the enthalpy and phase behavior of a selected ternary model compound system, representative of interactions present in coal derived liquids. Measurements were made in a Freon 11 reference fluid boil-off calorimeter, and an equilibrium flash vaporization apparatus. The ternary system included an aromatic, a basic nitrogen compound, and a cresol: the m-cresol/quinoline/tetralin ternary mixture. Measurements were made over a wide range of temperature (200 to 750/sup 0/F) and pressure (20 to 1500 psia), for the three pure compounds, the three binary mixtures and selected compositions of the ternary. Both enthalpy and phase behavior measurements were made. Equation of state parameters obtained from binary enthalpy data are more reliable when extrapolated to the ternary system, than parameters obtained from vapor liquid equilibrium data. Furthermore, the more complex mixing rules generally gave poorer predictions when extrapolated to ternary systems. 17 refs., 7 figs., 4 tabs.

  17. Extremes temperatures and enthalpy in Finland and Sweden in a changing climate

    Energy Technology Data Exchange (ETDEWEB)

    Venaelaeinen, A.; Saku, S.; Jylhae, K. (Finnish Meteorological Institute (Finland)); Nikulin, G.; Kjellstroem, E.; Baerring, L. (Swedish Meteorological Institute (Sweden))

    2009-06-15

    Though risks caused by harsh weather conditions are taken into account in the planning of nuclear power plants, some exceptional weather events or combination of different events may prevent normal power operation and simultaneously endanger safe shutdown of the plant. Extreme weather events could influence, for example, the external power grid connection, emergency diesel generators (blockage of air intakes), ventilation and cooling of electric and electronics equipment rooms and the seawater intake. Due to the influence of an intensified greenhouse effect the climate is changing rapidly during the coming decades and this change is expected to have an influence also on the occurrence of extreme weather events. In this report we have examined extreme temperatures. Enthalpy is a parameter that combines air temperature and air humidity and it is used in the design of air conditioning systems. Therefore, we have included also return levels of enthalpy in our analysis. The influence of climate change on extreme temperatures is analysed based on regional climate model simulations. The reoccurrence times of high temperatures combined with high air humidity was analysed based on measurements made at five Finnish and three Swedish meteorological stations. Based on the observational records we find the 10 year return level of daily maximum temperature to be around 32 deg. C and the 100 year return level around 35 deg. C. If we look the return levels of warm and humid conditions then for example in Helsinki the 10 year return level of one week mean temperature in case mean air humidity is above 80% is 20.1 deg. C. The 10 year return level of daily maximum enthalpy is around 60 kJ/kg and the 100 year return level almost 70 kJ/kg. According to the climate model simulations the largest increase of 50-year return level of daily maximum temperature is found in southern Sweden and south-western Finland. By the end of this century the increase can be 3-5 deg. C. The largest change

  18. Sleepiness or excessive daytime somnolence.

    Science.gov (United States)

    Edd, Ethel Mitty; Flores, Sandi

    2009-01-01

    Excessive daytime somnolence (EDS) is associated with age-related changes, environment, circadian rhythm or sleep pattern disorder, insomnia, medications, lifestyle factors, depression, pain, and illness. The notion of "sleep architecture" connotes a structure that describes the sleep cycle (i.e., stages) and wakefulness during a single sleep period-that is, rapid eye movement (REM) and non-REM sleep. Circadian rhythms perform a variety of functions including regulation of the quality and distribution of the stages of sleep. Insomnia includes delayed sleep onset as well as premature wakening; sleep is nonrestorative. Comorbidities associated with insomnia are Alzheimer's disease and other dementias, delirium, depression, congestive heart failure, chronic obstructive pulmonary disease, gastroesophageal reflux disease, pain, degenerative diseases of the neurological system, and sleep apnea. Continuous inadequate sleep affects cognitive function, physical performance, overall well-being, and quality of life. There is a greater risk of falls from insomnia than is the use of hypnotics to manage it. Sleep disruption among older adults is underrecognized and undertreated. Assessment using valid tools can be performed rapidly. There are a variety of treatment options, including sleep hygiene and pharmacological and alternative modalities.

  19. Extraction of maxillary first molars improves second and third molar inclinations in Class II Division 1 malocclusion

    NARCIS (Netherlands)

    Livas, C.; Halazonetis, D.J.; Booij, J.W.; Katsaros, C.

    2011-01-01

    INTRODUCTION: The aim of this study was to assess the changes in inclination of the maxillary second (M2) and third (M3) molars after orthodontic treatment of Class II Division 1 malocclusion with extraction of maxillary first molars. METHODS: Two groups of subjects were studied. The experimental

  20. Enthalpy measurement of coal-derived liquids. Combined quarterly technical progress reports, April-June 1979 and July-September 1979. [Effect of association

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1979-01-01

    Enthalpy measurements on a coal-derived naphtha and middle distillate, both produced by the SRC-II process, were made using flow calorimetry. The accuracy of the measurements, as reported by Omid, was within +- 1% of the measured enthalpy differences, ..delta..H. Experimental data for the naphtha were obtained over a pressure range of 100-300 psia and temperatures from 148/sup 0/ to 456/sup 0/F. The middle distillate enthalpy measurements were made in the pressure and temperature ranges of 130 to 1000 psia, and 157/sup 0/ to 675/sup 0/F, respectively. The methods of prediction of enthalpy developed for petroleum fractions were unsatisfactory when applied to the above data. A negative bias was observed in the predicted enthalpy values for several of the coal-liquids. Based on these results, it was theorized that the high experimental enthalpy values for coal-liquids were due to an energy of association attributed, primarily, to hydrogen-bonding effects. The petroleum-fraction enthalpy correlations were then tested on the experimental data for pure compounds, both associating and non-associating. The predicted values compared very well with the experimental results for non-associating model compounds. However, for associating model compounds the predicted enthalpy values were considerably lower than their experimental data. This served to confirm the basic premise that the high experimental enthalpy values, for model compounds and coal liquids, were a direct consequence of an energy of association attributed, primarily, to hydrogen-bonding effects.

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

    Science.gov (United States)

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

    1993-10-01

    In a calorimetric bomb equipped with an electric microfurnace for heating a sample, self-propagating high-temperature synthesis (SHS) of molybdenum boride is realized in accordance with the reaction Mo (c) +B (amorph.)=MoB (c); the enthalpy of this reaction is measured, and the standard enthalpy of formation of molybdenum boride from metal molybdenum and crystaline boron is calculated: Δf H 0 (MoB,c,δ,β)=103.9α1.2kJ/mole.

  2. Enthalpy and phase behavior of coal derived liquid mixtures. Ninth quarterly technical progress report, July-September 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1986-10-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid moedl compound mixtures. During the ninth quarter, enthalpy measurements on the pure component 1-methylnaphthalene were obtained. Also, during this quarter ternary vapor liquid equilibrium measurements for m-cresol/quinoline/tetralin have begun for the isotherms; 250, 275, 300, 325/sup 0/C. A maximum likelihood algorithm applicable for implicit constraints has been developed. The method was applied to the determination of interaction parameters for temperature and density dependent mixing rules from our binary vapor liquid equilibrium data. 16 refs., 51 figs., 14 tabs.

  3. 75 FR 27572 - Monthly Report of Excess Income and Annual Report of Uses of Excess Income

    Science.gov (United States)

    2010-05-17

    ... URBAN DEVELOPMENT Monthly Report of Excess Income and Annual Report of Uses of Excess Income AGENCY... subject proposal. Project owners are permitted to retain Excess Income for projects under terms and conditions established by HUD. Owners must request to retain some or all of their Excess Income. The request...

  4. Oxygen migration enthalpy likely limits oxide precipitate dissolution during tabula rasa

    Energy Technology Data Exchange (ETDEWEB)

    Looney, E. E.; Laine, H. S.; Youssef, A.; Jensen, M. A.; LaSalvia, V.; Stradins, P.; Buonassisi, T.

    2017-09-25

    In industrial silicon solar cells, oxygen-related defects lower device efficiencies by up to 20% (rel.). In order to mitigate these defects, a high-temperature homogenization anneal called tabula rasa (TR) that has been used in the electronics industry is now proposed for use in solar-grade wafers. This work addresses the kinetics of tabula rasa by elucidating the activation energy governing oxide precipitate dissolution, which is found to be 2.6 +/- 0.5 eV. This value is consistent within uncertainty to the migration enthalpy of oxygen interstitials in silicon, implying TR to be kinetically limited by oxygen point-defect diffusion. This large activation energy is observed to limit oxygen precipitate dissolution during standard TR conditions, suggesting that more aggressive annealing conditions than conventionally used are required for complete bulk microdefect mitigation.

  5. A Mixed Enthalpy-Temperature Finite Element Method For Generalized Phase-Change Problems

    DEFF Research Database (Denmark)

    krabbenhøft, Kristian; Damkilde, Lars

    2003-01-01

    In a large number of problems of engineering interest the transition of the material from one phase to another is of vital importance in describing the overall physical behaviour. Common applications include metal casting, freezing and thawing of foodstuffs and other biological materials, ground ...... freezing and solar energy storage. The phase-change problem is characterized by an abrupt change in enthalpy per unit temperature in a narrow temperature range around the freezing point.......In a large number of problems of engineering interest the transition of the material from one phase to another is of vital importance in describing the overall physical behaviour. Common applications include metal casting, freezing and thawing of foodstuffs and other biological materials, ground...

  6. Sub-Tg enthalpy relaxation in an unstable oxide glass former: insights into the structural heterogeneity

    DEFF Research Database (Denmark)

    Yue, Yuanzheng; Zhang, Yanfei

    Structural heterogeneity plays a crucial role in determining functionality of glasses. In this work we have found that the sub-Tg enthalpy relaxation pattern in a hyperquenched glass is highly sensitive to structural heterogeneity. As a consequence, the former can be used as an effective approach...... we chose the glass compositions with very different glass stabilities to crystallization. By using hyperquenching-annealing-calorimetry approach, we have observed that the pattern of calorimetric response below Tg dramatically varies with glass composition. The variations are attributed to different...... to detect and quantify the structural heterogeneity in glass-forming liquids. However, the chemical nature of structural heterogeneity should be revealed by other means such as high resolution microscopic and spectroscopic methods. To study the impact of the structural heterogeneity on the sub-Tg relaxation...

  7. Surface Catalysis and Oxidation on Stagnation Point Heat Flux Measurements in High Enthalpy Arc Jets

    Science.gov (United States)

    Nawaz, Anuscheh; Driver, David M.; Terrazas-Salinas

    2013-01-01

    Heat flux sensors are routinely used in arc jet facilities to determine heat transfer rates from plasma plume. The goal of this study is to assess the impact of surface composition changes on these heat flux sensors. Surface compositions can change due to oxidation and material deposition from the arc jet. Systematic surface analyses of the sensors were conducted before and after exposure to plasma. Currently copper is commonly used as surface material. Other surface materials were studied including nickel, constantan gold, platinum and silicon dioxide. The surfaces were exposed to plasma between 0.3 seconds and 3 seconds. Surface changes due to oxidation as well as copper deposition from the arc jets were observed. Results from changes in measured heat flux as a function of surface catalycity is given, along with a first assessment of enthalpy for these measurements. The use of cupric oxide is recommended for future heat flux measurements, due to its consistent surface composition arc jets.

  8. Communication: Enthalpy relaxation in a metal-organic zeolite imidazole framework (ZIF-4) glass-former

    Science.gov (United States)

    Xu, Di; Liu, Yingdan; Tian, Yongjun; Wang, Li-Min

    2017-03-01

    Amorphization in metal-organic framework materials initiated by the collapsed crystal offers new access to glasses; however, the understanding of such glasses remains to be clarified. Here, we studied the glass transition thermodynamics and kinetics in a zeolitic imidazolate framework ZIF-4 utilizing enthalpy relaxation measurements. The calorimetric glass transition profile and relaxation behaviors in ZIF-4 are found to reproduce the basic features and correlations manifested by conventional melt-quenched glasses. A comparison with various melt-quenched glasses suggests that the low fragility of ZIF-4 is ascribed to the low thermal-pressure coefficient due to the directional tetrahedral bond, partly leading to the low vibrational entropy in the melt-crystal entropy difference.

  9. Enthalpy Relaxation of a DGEBA Epoxy as a function of Time, Temperature, and Cooling Rate

    Science.gov (United States)

    Clarkson, Caitlyn M.; McCoy, John D.; Kropka, Jamie M.

    2015-03-01

    Enthalpy relaxation resulting from physical aging of a DGEBA epoxy, Epon 828, cross-linked with an amine curative, Jeffamine T-403, was studied for two isothermal aging temperatures at sequential aging times up to two weeks. Results were analyzed using the peak shift method to obtain the relaxation parameters β, δ (H*), and χ. The individual effects of cooling rate from the equilibrated state, aging time, and aging temperature were isolated to understand the initial state of the glassy epoxy and its evolution during physical aging. [Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  10. Experimental study on mass transfer of contaminants through an enthalpy recovery unit with polymer membrane foils

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Fang, Lei

    2014-01-01

    recovery unit with polymer membrane foils was used as refeering unit in this study. The experiments were conducted with different outdoor thermal climates e.g. warm-humid and cold-dry climates; isothermal and non isothermal as well as equal humidity and non equal humidity with indoor climate. Three......Laboratory experimental studies were conducted to investigate the mass transfer of contaminants through a total heat recovery unit with polymer membranes foils. The studies were conducted in twin climate chambers which simulated outdoor and indoor thermal climates. One manufacturd total heat...... could transfer from exhaust air to supply air through the enthalpy recovery unit. The mass transfer efficiency of contaminants was independent of the hygro-thermal differences between indoor and outdoor climate conditions. The mass transfer ratio of the chemical contaminants in the total heat recovery...

  11. New estimators for calculating solvation entropy and enthalpy and comparative assessments of their accuracy and precision.

    Science.gov (United States)

    Wyczalkowski, Matthew A; Vitalis, Andreas; Pappu, Rohit V

    2010-06-24

    We present two new methods for estimating the entropy and enthalpy decomposition of free energy calculations. These methods are based on temperature derivatives of the Bennett Acceptance Ratio and the Multistate Bennett Acceptance Ratio estimators, respectively. We test the accuracy of these new estimators using a simple one-dimensional model. A detailed assessment of their performance is reported by studying the solvation of N-methylacetamide. Finally, we quantify the free energies of solvation for 11 model compounds using the OPLS-AA force field and a variation of this force field. Thermodynamic decompositions of these calculated free energies are obtained to highlight the utility of these quantities for refining force field parameters by comparing computed free energies and their decompositions to their experimental counterparts.

  12. Enthalpy measurements of a syncrude and a distillate derived from Western Kentucky coal

    Energy Technology Data Exchange (ETDEWEB)

    Omid, H.; Andrew, J.R.; Kidnay, A.J.; Yesavage, V.F.

    1984-04-01

    Enthalpy data at pressures of 690, 3450, 6895, and 10340 kPa (100, 500, 1000, 1500 psia) for temperatures between 18.3 and 375/sup 0/C (65 to 705/sup 0/F) are presented for a Western Kentucky syncrude produced by the Char-Oil-Energy-Development (COED) process, and for a combined distillate of the Western Kentucky syncrude for pressures of 690, 3450, and 6895 kPa (60, 100, 500 psia) and temperatures between 18.3 and 402/sup 0/C (65 to 765/sup 0/F). The data were obtained in a boil-off calorimeter with Freon 11 (CFCl/sub 3/) as a reference fluid.

  13. Eruption status of third molars in South Indian city

    Directory of Open Access Journals (Sweden)

    Sujata M Byahatti

    2011-01-01

    Full Text Available Aim : The aim of the present study is to determine the number of third molars per person, angulation, level, amount of space for eruption of third molar between ramus of mandible and second molar status of root and also to study the difficulty index. Objective: To study the eruption status of third molar in South Indian population. Materials and methods: The study conducted at Department of Oral Medicine and Radiology. Maratha Mandals NG Halgekar College of Dental Sciences and Research Centre. Belgaum, Karnataka, India A total of 150 patients (54 females and 96 males visiting outpatient department between the age group of 17 and 30 with a mean age of 23.5 years were selected- Before starting the study, ethical concern taken from the ethical committee and informed consent from each patent who underwent radiographic examination. Results: The results showed approximately 94.66% of the subjects had all four third molars, 8.6% had three third molars, 4.6% had two third molars and 2% had one third molars with 3.3% having agenesis of all third molars. Third molar agenesis showed predilection for upper jaw with higher proportion in females (5 5% than males (2%. Angular position seen maximum with vertical position (66.16% with least being horizontal impactions. Level of occlusal plane of third molar similar to that of adjacent tooth seen in 52.65%. Below the occlusal plane in 19.61 %, totally impacted teeth noted in 27.73%. More than 75% of the teeth had complete root formation. Among total number of teeth, 518 (91.51 % teeth were easy to extract and remaining 33 (5.8% were difficult to extract. Conclusion: Radiological and clinical findings have correlated to assess whether teeth were easy to extract or difficult. Because of the increasing incidence of unerupted third molars and the association of numerous complications with these retained teeth, assessment of germ position and prognosis of third molar eruption is necessary for better patient management.

  14. Mass dependence of the activation enthalpy and entropy of unentangled linear alkane chains

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Cheol; Douglas, Jack F. [Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2015-10-14

    The mass scaling of the self-diffusion coefficient D of polymers in the liquid state, D ∼ M{sup β}, is one of the most basic characteristics of these complex fluids. Although traditional theories such as the Rouse and reptation models of unentangled and entangled polymer melts, respectively, predict that β is constant, this exponent for alkanes has been estimated experimentally to vary from −1.8 to −2.7 upon cooling. Significantly, β changes with temperature T under conditions where the chains are not entangled and at temperatures far above the glass transition temperature T{sub g} where dynamic heterogeneity does not complicate the description of the liquid dynamics. Based on atomistic molecular dynamics simulations on unentangled linear alkanes in the melt, we find that the variation of β with T can be directly attributed to the dependence of the enthalpy ΔH{sub a} and entropy ΔS{sub a} of activation on the number of alkane backbone carbon atoms, n. In addition, we find a sharp change in the melt dynamics near a “critical” chain length, n ≈ 17. A close examination of this phenomenon indicates that a “buckling transition” from rod-like to coiled chain configurations occurs at this characteristic chain length and distinct entropy-enthalpy compensation relations, ΔS{sub a} ∝ ΔH{sub a}, hold on either side of this polymer conformational transition. We conclude that the activation free energy parameters exert a significant influence on the dynamics of polymer melts that is not anticipated by either the Rouse and reptation models. In addition to changes of ΔH{sub a} and ΔS{sub a} with M, we expect changes in these free energy parameters to be crucial for understanding the dynamics of polymer blends, nanocomposites, and confined polymers because of changes of the fluid free energy by interfacial interactions and geometrical confinement.

  15. Mass dependence of the activation enthalpy and entropy of unentangled linear alkane chains

    Science.gov (United States)

    Jeong, Cheol; Douglas, Jack F.

    2015-10-01

    The mass scaling of the self-diffusion coefficient D of polymers in the liquid state, D ˜ Mβ, is one of the most basic characteristics of these complex fluids. Although traditional theories such as the Rouse and reptation models of unentangled and entangled polymer melts, respectively, predict that β is constant, this exponent for alkanes has been estimated experimentally to vary from -1.8 to -2.7 upon cooling. Significantly, β changes with temperature T under conditions where the chains are not entangled and at temperatures far above the glass transition temperature Tg where dynamic heterogeneity does not complicate the description of the liquid dynamics. Based on atomistic molecular dynamics simulations on unentangled linear alkanes in the melt, we find that the variation of β with T can be directly attributed to the dependence of the enthalpy ΔHa and entropy ΔSa of activation on the number of alkane backbone carbon atoms, n. In addition, we find a sharp change in the melt dynamics near a "critical" chain length, n ≈ 17. A close examination of this phenomenon indicates that a "buckling transition" from rod-like to coiled chain configurations occurs at this characteristic chain length and distinct entropy-enthalpy compensation relations, ΔSa ∝ ΔHa, hold on either side of this polymer conformational transition. We conclude that the activation free energy parameters exert a significant influence on the dynamics of polymer melts that is not anticipated by either the Rouse and reptation models. In addition to changes of ΔHa and ΔSa with M, we expect changes in these free energy parameters to be crucial for understanding the dynamics of polymer blends, nanocomposites, and confined polymers because of changes of the fluid free energy by interfacial interactions and geometrical confinement.

  16. Measuring Enthalpy of Sublimation of Volatiles by Means of Piezoelectric Crystal Microbalances

    Science.gov (United States)

    Dirri, Fabrizio; Palomba, Ernesto; Longobardo, Andrea; Zampetti, Emiliano

    2017-12-01

    Piezoelectric Crystal Microbalances (PCM's) are widely used to study the chemical processes involving volatile compounds in any environment, such as condensation process. Since PCM's are miniaturized sensor, they are very suitable for planetary in situ missions, where can be used to detect and to measure the mass amount of astrobiologically significant compounds, such as water and organics. This work focuses on the realization and testing of a new experimental setup, able to characterize volatiles which can be found in a planetary environment. In particular the enthalpy of sublimation of some dicarboxylic acids has been measured. The importance of dicarboxylic acids in planetology and astrobiology is due to the fact that they have been detected in carbonaceous chondritic material (e.g. Murchinson), among the most pristine material present in our Solar System. In this work, a sample of acid was heated in an effusion cell up to its sublimation. For a set of temperatures (from 30 °C to 75 °C), the deposition rate on the PCM surface has been measured. From these measurements, it has been possible to infer the enthalpy of sublimation of Adipic acid, i.e. ΔH = 141.6 ± 0.8 kJ/mol and Succinic acid, i.e. ΔH = 113.3 ± 1.3 kJ/mol. This technique has so demonstrated to be a good choice to recognise a single compound or a mixture (with an analysis upstream) even if some improvements concerning the thermal stabilization of the system will be implemented in order to enhance the results' accuracy. The experiment has been performed in support of the VISTA (Volatile In Situ Thermogravimetry Analyzer) project, which is included in the scientific payload of the ESA MarcoPolo-R mission study.

  17. Heat transport modeling for the design of a low enthalpy open-loop system

    Directory of Open Access Journals (Sweden)

    Leonardo Piccinini

    2012-12-01

    Full Text Available A case study of hydrogeological characterization and heat transport modeling for the design of a low enthalpy system in the Province of Treviso (Italy is here presented. It is an open loop system that pumps and re-injects groundwater from a confined aquifer of the high Veneto plain. This type of systems is the most efficient in terms of yield, but its construction is highly conditioned by the availability of groundwater resource and by the environmental laws related to groundwater exploitation. Groundwater flow modeling with MODFLOW 2005 led to a good aquifer parameters estimation, by means of the quantitative calibration of a pumping test made on the pumping well and an observation piezometer. Then, with the heat transport modeling with SEAWAT 4 the distance between pumping well and re-injecting well has been optimized, avoiding so the thermal feedback effect. The lack of sitespecific data for dispersivity parameters has been solved through a sensitivity analysis on the main dispersivity parameters of heat transport. Finally, in order to comply with the environmental laws, a long-term forecasting simulation (duration of 20 years has been set up in order to evaluate the open loop system thermal impact on the aquifer. The obtained results put in evidence that the design of low enthalpy systems strongly needs a detailed hydrogeological characterization of the aquifer interested by the pumping and that numerical modeling is the most effective tool in support of the definition of the optimal distance between pumping and re-injecting wells in the open loop systems.

  18. An evaluation for harnessing low-enthalpy geothermal energy in the Limpopo Province, South Africa

    Directory of Open Access Journals (Sweden)

    Taufeeq Dhansay

    2014-03-01

    Full Text Available South Africa generates most of its energy requirements from coal, and is now the leading carbon emitter in Africa, and has one of the highest rates of emissions of all nations in the world. In an attempt to decrease its CO2 emissions, South Africa continues to research and develop alternative forms of energy, expand on the development of nuclear and has began to explore potentially vast shale gas reserves. In this mix, geothermal has not been considered to date as an alternative energy source. This omission appears to stem largely from the popular belief that South Africa is tectonically too stable. In this study, we investigated low-enthalpy geothermal energy from one of a number of anomalously elevated heat flow regions in South Africa. Here, we consider a 75-MW enhanced geothermal systems plant in the Limpopo Province, sustainable over a 30-year period. All parameters were inculcated within a levelised cost of electricity model that calculates the single unit cost of electricity and tests its viability and potential impact toward South Africa's future energy security and CO2 reduction. The cost of electricity produced is estimated at 14 USc/KWh, almost double that of coal-generated energy. However, a USD25/MWh renewable energy tax incentive has the potential of making enhanced geothermal systems comparable with other renewable energy sources. It also has the potential of CO2 mitigation by up to 1.5 gCO2/KWh. Considering the aggressive nature of the global climate change combat and South Africa's need for a larger renewable energy base, low-enthalpy geothermal energy could potentially form another energy option in South Africa's alternative energy basket.

  19. Evaluation of the ground surface Enthalpy balance from bedrock temperatures (Livingston Island, Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2009-05-01

    Full Text Available The annual evolution of the ground temperatures from Incinerador borehole in Livingston Island (South Shetlands, Antarctic is studied. The borehole is 2.4 m deep and is located in a massive quartzite outcrop with negligible water content, in the proximity of the Spanish Antarctic Station Juan Carlos I. In order to model the movement of the 0°C isotherm (velocity and maximum depth hourly temperature profiles from: (i the cooling periods of the frost season of 2000 to 2005, and (ii the warming periods of the thaw season of 2002–2003, 2003–2004 and 2004–2005, were studied. In this modelling approach, heat gains and losses across the ground surface are assumed to be the causes for the 0°C isotherm movement. A methodological approach to calculate the ground Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change into the rock is equivalent to the heat exchange through the ground surface during each season, thus enabling to describe the interaction ground-atmosphere and providing valuable data for studies on permafrost and periglacial processes. The bedrock density and thermal conductivity are considered to be constant and initial isothermal conditions at 0°C are assumed (based in collected data and local meteorological conditions in this area to run the model in the beginning of each season. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima. The application of this method avoids error propagation induced by the heat exchange calculations from multiple sensors using the Fourier method.

  20. Enthalpy-Driven RNA Folding: Single-Molecule Thermodynamics of Tetraloop–Receptor Tertiary Interaction†

    Science.gov (United States)

    Fiore, Julie L.; Kraemer, Benedikt; Koberling, Felix; Edmann, Rainer; Nesbitt, David J.

    2010-01-01

    RNA folding thermodynamics are crucial for structure prediction, which requires characterization of both enthalpic and entropic contributions of tertiary motifs to conformational stability. We explore the temperature dependence of RNA folding due to the ubiquitous GAAA tetraloop–receptor docking interaction, exploiting immobilized and freely diffusing single-molecule fluorescence resonance energy transfer (smFRET) methods. The equilibrium constant for intramolecular docking is obtained as a function of temperature (T = 21–47 °C), from which a van’t Hoff analysis yields the enthalpy (ΔH°) and entropy (ΔS°) of docking. Tetraloop–receptor docking is significantly exothermic and entropically unfavorable in 1 mM MgCl2 and 100 mM NaCl, with excellent agreement between immobilized (ΔH° = −17.4 ± 1.6 kcal/mol, and ΔS° = −56.2 ± 5.4 cal mol−1 K−1) and freely diffusing (ΔH° = −17.2 ± 1.6 kcal/mol, and ΔS° = −55.9 ± 5.2 cal mol−1 K−1) species. Kinetic heterogeneity in the tetraloop–receptor construct is unaffected over the temperature range investigated, indicating a large energy barrier for interconversion between the actively docking and nondocking subpopulations. Formation of the tetraloop–receptor interaction can account for ~60% of the ΔH° and ΔS° of P4–P6 domain folding in the Tetrahymena ribozyme, suggesting that it may act as a thermodynamic clamp for the domain. Comparison of the isolated tetraloop–receptor and other tertiary folding thermodynamics supports a theme that enthalpy- versus entropy-driven folding is determined by the number of hydrogen bonding and base stacking interactions. PMID:19186984

  1. Molar-incisor hypomineralization: Therapeutic challenge to paediatric dentistry practice

    Directory of Open Access Journals (Sweden)

    Stojković Branislava

    2017-01-01

    Full Text Available Introduction: Molar incisor hypomineralization indicates the appearance of enamel hypomineralization of systemic origin which occurs in 1-4 first permanent molars, which is often accompanied by changes on permanent incisors. Variations in clinical manifestation, together with commonly present asymmetry, are the reason for large variations in the needs for therapeutic treatment of these structural enamel defects. Case study: Two patients with diagnosed molar incisor hypomineralization are shown. The first patient, a six-year-old girl, with diagnosed mild clinical form, visited the dentist immediately after the eruption of the first permanent molars. Early diagnosis and timely application of preventive-profilactic measures, together with mild clinical form, are the reason for prevention of dental caries and further spreading of posteruptive enamel breakdown on affected first molars. Unlike the first one, the second patient, a 7,5-year-old girl had the diagnosis of moderate molar incisor hypomineralization. She developed dental caries on tooth 46 as well as complication in dental caries on tooth 36 which was extracted soon after the eruption. Conclusion: Early diagnosis and the severity of clinical appearance are the most important factors which determine therapeutic outcome of the treatment of molar incisor hypomineralization.

  2. Excess Volumes, Densities, Speeds of Sound, and Viscosities for the Binary Systems of 1-Octanol with Hexadecane and Squalane at (298.15, 303.15 and 308.15) K

    Science.gov (United States)

    Dubey, Gyan P.; Sharma, Monika

    2008-08-01

    Excess molar volumes, {V_m^E } , excess molar isentropic compressibilities, {K_{S,m}^E } , and deviations of the speeds of sound, u D, from their ideal values u id in an ideal mixture for binary mixtures of 1-octanol, C8H17OH, with hexadecane, C16H34, and squalane (2,6,10,15,19,23-hexamethyltetracosane), C30H62, at T = (298.15, 303.15, and 308.15) K and at atmospheric pressure were derived from experimental density, ρ, and speed-of-sound data, u. Viscosity measurements were also carried out for the same mixtures. The Prigogine-Flory-Patterson (PFP) theory has been applied to analyze {V_m^E} of these systems. Furthermore, the apparent molar volumes, {overline{{V}}_{\\varphi ,i}^0 } and apparent molar compressibility, {overline{{K}}_{\\varphi ,i}^{ 0} } of the components at infinite dilution have been calculated.

  3. Response of molars and non-molars to a strict supragingival control in periodontal patients

    Directory of Open Access Journals (Sweden)

    Patrícia Daniela Melchiors Angst

    2013-02-01

    Full Text Available The posterior position in the arches is one of the factors that underlies the poor prognosis of molar teeth (M. It is speculated that M do not benefit from the oral hygiene routine as well as non-molars (NM do. This study evaluated the response of M and NM to supragingival control during a 6-month period in 25 smokers (S and 25 never-smokers (NS with moderate-to-severe periodontitis. One calibrated examiner assessed visible plaque (VPI and gingival bleeding (GBI indexes, periodontal probing depth (PPD, bleeding on probing (BOP, and clinical attachment loss (CAL at days 0 (baseline, 30 and 180. At baseline, M showed significantly higher mean values of VPI (p = 0.017 and PPD (p < 0.001 compared with NM; CAL was also greater in M (p < 0.001 and was affected by smoking (p = 0.007. The reductions obtained for periodontal indicators at day 180 showed similar responses between M and NM. For CAL, M (NS 0.57 ± 0.50; S 0.67 ± 0.64 and NM (NS 0.38 ± 0.23; S 0.50 ± 0.33 reached an almost significant difference (p = 0.05. Smoking did not influence the response to treatment. Multilevel analysis revealed that, only for PDD reductions, the interaction between sites, teeth and patient was significant (p < 0.001. It was concluded that M benefit from an adequate regimen of supragingival biofilm control; therefore, supragingival condition should be considered in the prognosis of molar teeth.

  4. Surgical approach to impacted mandibular third molars--operative classification.

    Science.gov (United States)

    Abu-El Naaj, Imad; Braun, Refael; Leiser, Yoav; Peled, Micha

    2010-03-01

    The aim of the present study is to suggest a convenient way to classify the position of the impacted third mandibular molar relative to the mandibular canal and to suggest indications for the use of each surgical approach for mandibular third molar extraction. The presented new typing system, Third Molar Classification (TMC), is a simple and easy-to-apply method for the surgical management of mandibular third molars and can be extended for any ectopic or impacted mandibular tooth. There are 3 major types of third molar positions. The second type is subdivided further into 2 subtypes. In the present study, 9 patients with high-risk mandibular third molars were treated according to the present classification and are presented and discussed. Patients typed as TMC IIb were treated with a sagittal split osteotomy approach and patients typed as TMC III were treated with an extraoral approach. The operative classification was successfully implemented in very rare cases of deeply impacted mandibular third molars. In 3 of 9 cases (33%) minor complications included some degree of hypoesthesia using the extraoral approach; these complications resolved spontaneously without the need for any intervention. The present study describes the use of a new surgical classification system for treatment planning in all types of mandibular third molar extractions. We believe that the present classification could help the oral and maxillofacial surgeon in decision-making and limit the possible risks that are present when attempting to extract impacted mandibular third molars. Copyright (c) 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  5. Autotransplantation of a mandibular third molar: A case report

    Directory of Open Access Journals (Sweden)

    Elham Najafi

    2017-09-01

    Full Text Available Tooth autotransplantation defines as transition of one tooth from one position to another, in same individual. It is a biological procedure in which teeth have the potential to induce alveolar bone growth. It can be applied in patients before adolescence growth is finished. It significantly reduces time and cost compared to implants. Healing rapidly occurs and function is regained almost immediately. Our case was a 15-year-old male that his left mandibular third molar transplanted to the second molar sight after extraction of second molar because of unrestorable crown. During 9 month follow up transplanted tooth was asymptomatic, functional and responsive to sensibility tests. (Cold test, EPT.

  6. Molar Pregnancy with a Co-Existing Viable Fetus

    Directory of Open Access Journals (Sweden)

    Ruya Deveer

    2014-03-01

    Full Text Available     The aim of this study was to report the clinical features, management, and outcome of a case of molar pregnancy with a coexisting viable fetus and to review the literature. In this article, we report a case of pregnancy with diffuse placental molar change and a normal fetus which presented with hyperemesis gravidarum and hyperthyroidism. Genetic amniocentesis showed normal fetal karyotype. A healthy full-term live male infant was delivered by cesarean section. In molar pregnancies with a normal karyotype fetus, with intensive maternal follow-up, continuation of pregnancy can be suggested.

  7. Elongational viscosity of narrow molar mass distribution polystyrene

    DEFF Research Database (Denmark)

    Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz

    2003-01-01

    above the linear viscoelastic prediction at intermediate strains, indicating strain hardening. The steady elongational viscosities are monotone decreasing functions of elongation rate. At elongation rates larger than the inverse reptation time, the steady elongational viscosity scales linearly......Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...... with molar mass at fixed elongation rate....

  8. Solubility and interaction parameters as references for solution properties. I. Exceptional mixing and excess functions.

    Science.gov (United States)

    Rosenholm, Jarl B

    2009-02-28

    In order to focus on salient interactions it is customary to design a parameter network representing the reference (ideal) molecular behavior. Such reference properties are subtracted from the experimental data and the difference is analyzed. Each network is based on generally agreed thermodynamic dependent and independent variables defining unambiguously the state of the system. Unfortunately, more correction terms have been introduced making the relationship with traditional thermodynamic networks dependent on each system investigated. A critical comparison is made on the conceptual constraints introduced when developing the two most utilized reference thermodynamic networks. The first is represented by the standard mixing and excess functions of Gibbs free energy. The second represents tailored models involving van der Waals liquids and polymer solutions. Although the mixing and excess functions are formally same, their definition varies dramatically. Unfortunately this influences the analysis of divergence from the reference function, resulting in serious consequences as shown by the entropy and enthalpy obtained from temperature dependency. Moreover, entirely new functions relating to multiple solubility parameters in excess of standard van der Waals behavior are developed since reference data for these models are easily accessible.

  9. [Germectomy. The germ of the third mandibular molar in children: remove or preserve?].

    Science.gov (United States)

    Voorsmit, R A; van den Bergh, A W

    1992-11-01

    Third molars are often removed in order to prevent complications and various other problems associated with impacted third molars and their removal. Abortion of mandibular third molars is a procedure carried out at an early age in those subjects where there is insufficient room for the eruption of the third molars. On the other hand one can also decide to remove the second molars and to annexate orthodontically the third molars in the arch.

  10. A three-dimensional finite element analysis of molar distalization with a palatal plate, pendulum, and headgear according to molar eruption stage.

    Science.gov (United States)

    Kang, Ju-Man; Park, Jae Hyun; Bayome, Mohamed; Oh, Moonbee; Park, Chong Ook; Kook, Yoon-Ah; Mo, Sung-Seo

    2016-09-01

    This study aimed to (1) evaluate the effects of maxillary second and third molar eruption status on the distalization of first molars with a modified palatal anchorage plate (MPAP), and (2) compare the results to the outcomes of the use of a pendulum and that of a headgear using three-dimensional finite element analysis. Three eruption stages were established: an erupting second molar at the cervical one-third of the first molar root (Stage 1), a fully erupted second molar (Stage 2), and an erupting third molar at the cervical one-third of the second molar root (Stage 3). Retraction forces were applied via three anchorage appliance models: an MPAP with bracket and archwire, a bone-anchored pendulum appliance, and cervical-pull headgear. An MPAP showed greater root movement of the first molar than crown movement, and this was more noticeable in Stages 2 and 3. With the other devices, the first molar showed distal tipping. Transversely, the first molar had mesial-out rotation with headgear and mesial-in rotation with the other devices. Vertically, the first molar was intruded with an MPAP, and extruded with the other appliances. The second molar eruption stage had an effect on molar distalization, but the third molar follicle had no effect. The application of an MPAP may be an effective treatment option for maxillary molar distalization.

  11. Review of molar tooth structure research

    Directory of Open Access Journals (Sweden)

    Hong-Wei Kuang

    2014-10-01

    Full Text Available For more than a century, molar tooth structure (MTS has been studied. The study developed in three stages. During the first stage (before 1980, researchers described three basic morphologies of MTS, mainly from the Belt Supergroup in North America, and they provided several hypotheses for the origin of MTS. During the second stage (1980–1999, the frequent discoveries of MTS on all continents resulted in many detailed descriptions of their shape and in several hypotheses concerning the origin of MTS. Notably, hypotheses of MTS’s origin such as seismic activity and biological activity were developed. Since 2000, research has progressed into a new stage (the third stage. This is due to discoveries of MTS in the Meso–Neoproterozoic of China and elsewhere, and the ongoing debate on the seismic or biological origin is replaced by a hypothesis that involves gas expansion and chemically-controlled carbonate precipitation (both of them possibly affected by biological activities. This latter idea has gradually been commonly recognized as the mainstream theory. Despite continued disagreements, researchers now agree that microsparry calcite played a controlling role regarding the development and the global distribution of MTS in time and space during the Proterozoic, the morphological diversity, and the impact on the sedimentary environment. The present contribution analyses the three major hypotheses regarding the origin of MTS; it also discusses the shortcomings of the hypotheses regarding a seismic or biologic origin, and it details the modern hypothesis that links formation of cracks to the precipitation of sparry calcite. It is deduced that important questions dealing with the Precambrian can be answered, among other aspects regarding the depositional palaeogeography and stratigraphic correlations.

  12. Preformed crowns for decayed primary molar teeth.

    Science.gov (United States)

    Innes, Nicola P T; Ricketts, David; Chong, Lee Yee; Keightley, Alexander J; Lamont, Thomas; Santamaria, Ruth M

    2015-12-31

    Crowns for primary molars are preformed and come in a variety of sizes and materials to be placed over decayed or developmentally defective teeth. They can be made completely of stainless steel (know as 'preformed metal crowns' or PMCs), or to give better aesthetics, may be made of stainless steel with a white veneer cover or made wholly of a white ceramic material. In most cases, teeth are trimmed for the crowns to be fitted conventionally using a local anaesthetic. However, in the case of the Hall Technique, PMCs are pushed over the tooth with no local anaesthetic, carious tissue removal or tooth preparation. Crowns are recommended for restoring primary molar teeth that have had a pulp treatment, are very decayed or are badly broken down. However, few dental practitioners use them in clinical practice. This review updates the original review published in 2007. Primary objectiveTo evaluate the clinical effectiveness and safety of all types of preformed crowns for restoring primary teeth compared with conventional filling materials (such as amalgam, composite, glass ionomer, resin modified glass ionomer and compomers), other types of crowns or methods of crown placement, non-restorative caries treatment or no treatment. Secondary objectiveTo explore whether the extent of decay has an effect on the clinical outcome of primary teeth restored with all types of preformed crowns compared with those restored with conventional filling materials. We searched the following electronic databases: Cochrane Oral Health Group Trials Register (to 21 January 2015), Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library, 2014, Issue 12), MEDLINE via Ovid (1946 to 21 January 2015) and EMBASE via Ovid (1980 to 21 January 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform for ongoing trials and Open Grey for grey literature (to

  13. Determination of saturation pressure and enthalpy of vaporization of semi-volatile aerosols: the integrated volume mentod

    Science.gov (United States)

    This study presents the integrated volume method for estimating saturation pressure and enthalpy of vaporization of a whole aerosol distribution. We measure the change of total volume of an aerosol distribution between a reference state and several heated states, with the heating...

  14. Determining the Enthalpy of Vaporization of Salt Solutions Using the Cooling Effect of a Bubble Column Evaporator

    Science.gov (United States)

    Fan, Chao; Pashley, Richard M.

    2016-01-01

    The enthalpy of vaporization (?H[subscript vap]) of salt solutions is not easily measured, as a certain quantity of pure water has to be evaporated from a solution, at constant composition, and at a fixed temperature and pressure; then the corresponding heat input has to be measured. However, a simple bubble column evaporator (BCE) was used as a…

  15. Measurements of high-pressure steam-water enthalpy/void migration in unequally heated horizontal twin subchannels

    Energy Technology Data Exchange (ETDEWEB)

    Sutradhar, S.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]. E-mail: sutradhars@aecl.ca; Yin, S.T. [Consultant, Toronto, Ontario (Canada)]. E-mail: yinst@sympatico.ca; Tain, R.M. [Industrial Technology Research Inst., Chutung, Hsinchu, Taiwan (China)]. E-mail: rtain@itri.org.tw

    2006-07-01

    An experimental study of enthalpy/void migration in two interconnected, unequally heated horizontal subchannels was conducted using high-pressure steam-water as the operating medium. The cross-sectional geometry of the twin subchannels simulated two adjacent, top-to-bottom aligned inner subchannels of a 37-element CANDU fuel bundle. The effect of unequal heating on enthalpy/void migration was measured using three different heat flux ratios of 1.00, 1.11 and 1.21, with the higher heat flux in the top subchannel. The test results indicated that under similar flow conditions, the unequal heat flux set-up enhanced the enthalpy/void migration from the bottom to the top subchannel compared to the equal heat flux set up. This study quantifies and characterizes the buoyancy-induced enthalpy/void migration between two interconnected horizontal subchannels subject to different heat fluxes. The database will be used to validate and improve the flow-mixing models in subchannel codes. (author)

  16. Enthalpy changes during photosynthetic water oxidation tracked by time-resolved calorimetry using a photothermal beam deflection technique.

    Science.gov (United States)

    Krivanek, Roland; Dau, Holger; Haumann, Michael

    2008-03-01

    The energetics of the individual reaction steps in the catalytic cycle of photosynthetic water oxidation at the Mn(4)Ca complex of photosystem II (PSII) are of prime interest. We studied the electron transfer reactions in oxygen-evolving PSII membrane particles from spinach by a photothermal beam deflection technique, allowing for time-resolved calorimetry in the micro- to millisecond domain. For an ideal quantum yield of 100%, the enthalpy change, DeltaH, coupled to the formation of the radical pair Y(Z)(.+)Q(A)(-) (where Y(Z) is Tyr-161 of the D1 subunit of PSII) is estimated as -820 +/- 250 meV. For a lower quantum yield of 70%, the enthalpy change is estimated to be -400 +/- 250 meV. The observed nonthermal signal possibly is due to a contraction of the PSII protein volume (apparent DeltaV of about -13 A(3)). For the first time, the enthalpy change of the O(2)-evolving transition of the S-state cycle was monitored directly. Surprisingly, the reaction is only slightly exergonic. A value of DeltaH(S(3)-->S(0)) of -210 meV is estimated, but also an enthalpy change of zero is within the error range. A prominent nonthermal photothermal beam deflection signal (apparent DeltaV of about +42 A(3)) may reflect O(2) and proton release from the manganese complex, but also reorganization of the protein matrix.

  17. A novel approach for building up infraoccluded ankylosed primary molars in cases of missing premolars: A case report.

    Science.gov (United States)

    Lygidakis, N A; Chatzidimitriou, K; Lygidakis, N N

    2015-10-01

    In cases of infraoccluded primary molars associated with agenesis of premolars, any treatment plan occasionally includes retention of the primary teeth for space preservation and future implant placement if needed. In these cases, building up the crowns to the occlusal line is necessary to prevent various clinical problems. The present case report describes in detail a novel but simple clinical approach for retention and building up of the crown of infraoccluded primary molars. The technique is presented in a 14-year-old girl with nine missing permanent teeth. Orthodontic evaluation indicated space closure for five teeth and space maintenance in the remaining four second primary molars, three of them being infraoccluded. The technique included the following clinical steps: (a) elastic separators were placed proximally to the primary molars for few days to create space; (b) proximal minimal reduction of the crown width was performed; a direct hand composite resin core was made to increase crown height facilitating the selection of a preformed metal crown (PMC). The selected PMC was filled with self-curing composite resin and placed on the primary tooth following an acid etch and adhesive procedure; excess cervical material was removed; (c) after polymerisation, the PMC was carefully removed using cutting and hand instruments, revealing the composite resin fabricated crown which was adjusted for occlusion and polished. Radiographic evaluation confirmed the result. This simple method for infraoccluded primary molars crown building up to occlusion using conventional instruments and materials, appears to be a valuable clinical tool for paediatric dentists who frequently find themselves dealing with primary teeth that need to be retained and which can produce serious clinical problems if left untreated.

  18. Role of the excess monomer in the growth of urea and formaldehyde resin deposit particles.

    Science.gov (United States)

    Hao, Zhixian; Guo, Yuqing; Mansuer, Mulati; Zhu, Junfu; Zhu, Zhirong

    2014-09-15

    The role of excess monomer (i.e., Urea (U) or Formaldehyde (F)) in UF precipitation reaction was investigated at 28°C. The maximum output of the UF resin deposit was found around the U:F molar ratio 1.0:1.0 and this output decreased if excessive urea (or formaldehyde) was used in the reaction system. The excess monomer was considered to decrease the polymerization degree of UF resin deposit and increased the bonding saturation of its copolymerization monomer as well as the solubility of the UF resin deposit. The Influence of the excess monomer on the lamellar crystallinity of the resultant deposit, involving the polymerization degree and bonding saturation of the monomer, was examined. Three different dynamic regions containing excess monomers were revealed according to the behaviors of the deposit nucleation. The density and water absorption of the UF resin particles were finally demonstrated relative to the dynamic regions in their nucleation reactions. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Mandibular second molar periodontal healing after impacted third molar extraction in young adults.

    Science.gov (United States)

    Faria, Ana Inocêncio; Gallas-Torreira, Mercedes; López-Ratón, Mónica

    2012-12-01

    To estimate the prevalence of preoperative periodontal defects and analyze 12-month spontaneous healing on the distal aspect of the mandibular second molar (M2) after impacted mandibular third molar (M3) extraction. This prospective clinical study was conducted in 25 healthy young patients (21.03 ± 4.38 yr old) with 40 extractions of higher-risk periodontal impacted M3s. Plaque and gingival indexes, recession, bleeding on probing, probing depth (PD), and attachment level were recorded before surgery and at 3, 6, and 12 months after surgery at 5 sites on the distal aspect of the M2. The initial mean PD was 5.70 ± 3.80 mm, with the deepest mean PD at the lingual side. At 12 months, a mean PD average of 3.77 ± 2.86 mm was recorded, with a total average recovery of 1.93 ± 2.46 mm (P periodontal defects that are deepest at the lingual side and almost recover at 12 months after extraction. The first 3 months is considered the cutoff for periodontal healing. Young adults with high-risk periodontal M3 impactions may benefit from early extraction, which increases spontaneous periodontal healing. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Hipomineralização molar-incisivo = Molar incisor hypomineralization

    Directory of Open Access Journals (Sweden)

    Basso, Ana Paula

    2007-01-01

    Full Text Available A hipomineralização-molar incisivo (HMI é um defeito de origem sistêmica no esmalte dentário de primeiros molares e incisivos permanentes. Nesta condição, o esmalte hipomineralizado é frágil e pode se destacar facilmente, deixando a dentina exposta e causando, assim, problemas como sensibilidade dentária e maior risco ao estabelecimento de lesões de cárie. A HMI é freqüentemente confundida com fluorose ou amelogênese imperfeita e sua prevalência varia de 3,6 a 25%. Vários fatores etiológicos são citados para a condição e estão freqüentemente relacionados com doenças na infância nos primeiros três anos de vida. O tratamento envolve desde a restauração dos dentes afetados com materiais adesivos ou até mesmo a extração dos mesmos, dependendo da severidade do caso

  1. Enthalpy and phase behavior of coal derived liquid mixtures: Technical progress report for the period April-June 1987. [1-methylnaphthalene

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1987-07-31

    On July 15, 1984, work was initiated on a program to study the enthalpy and phase behavior of coal derived liquid model compound mixtures. During the twelfth quarter, enthalpy measurements for the compound of 1-methylnaphthalene have been completed and are included in Table 1. 16 refs., 5 figs., 4 tabs.

  2. Impacted Mandibular Third Molars: Review of Literature and a ...

    African Journals Online (AJOL)

    Impacted Mandibular Third Molars: Review of Literature and a Proposal of a Combined ... Annals of Medical and Health Sciences Research ... has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader).

  3. Prediction of postoperative pain after mandibular third molar surgery

    DEFF Research Database (Denmark)

    Rudin, Asa; Eriksson, Lars; Liedholm, Rolf

    2010-01-01

    To evaluate the predictive potential of preoperative psychological and psychophysiological variables in estimating severity of postoperative pain following mandibular third molar surgery (MTMS). Methods: Following ethical committee approval and informed consent, 40 consecutive patients scheduled...

  4. Má oclusão Classe I de Angle tratada com extrações de primeiros molares permanentes Angle Class I malocclusion treated with extraction of first permanent molars

    Directory of Open Access Journals (Sweden)

    Ivan Tadeu Pinheiro da Silva

    2010-08-01

    Full Text Available A má oclusão Classe I de Angle é caracterizada por uma relação anteroposterior normal nos molares, que pode ou não estar acompanhada por alterações esqueléticas - nos planos vertical ou transverso - ou dentárias. A biprotrusão, revelada pela inclinação acentuada dos incisivos superiores e inferiores para vestibular, somada ao trespasse horizontal excessivo, faz com que o paciente fique mais exposto a traumas dentários, além de causar comprometimento estético. A escolha dos dentes a serem extraídos para a correção, geralmente, recai sobre os primeiros ou segundos pré-molares, devido à sua posição na arcada. Contudo, a extração do primeiro molar permanente, em função de algum comprometimento, por cárie ou restauração extensa, pode ser uma alternativa, proporcionando a manutenção de um dente hígido em detrimento de outro já manipulado. O presente caso, tratado de maneira incomum, pela extração dos quatro primeiros molares permanentes, foi apresentado à Diretoria do Board Brasileiro de Ortodontia e Ortopedia Facial (BBO, representando a categoria 2, como parte dos requisitos para a obtenção do título de diplomado pelo BBO.Angle Class I malocclusion is characterized by normal anteroposterior molar relationship, which may or may not be accompanied by skeletal changes-in the vertical or transverse planes-or dental changes. Bimaxillary dental protrusion, characterized by pronounced labial inclination of maxillary and mandibular incisors combined with excessive overjet, expose patients to dental trauma and compromise aesthetics. In deciding which teeth to extract for Class I correction the first or second premolars are usually selected due to their location in the dental arch. However, the extraction of a first permanent molar compromised by caries or extensive restoration may be an alternative that ensures the preservation of a healthy tooth instead of one that has already been manipulated. This case, treated in

  5. Managing molar-incisor hypomineralization: A systematic review.

    Science.gov (United States)

    Elhennawy, Karim; Schwendicke, Falk

    2016-12-01

    We systematically reviewed treatment modalities for MIH-affected molars and incisors. Trials on humans with ≥1 MIH molar/incisor reporting on various treatments were included. Two authors independently searched and extracted records. Sample-size-weighted annual failure rates were estimated where appropriate. The risk of bias was assessed using the Newcastle-Ottawa scale. Electronic databases (PubMed, Embase, Cochrane CENTRAL, Google Scholar) were screened, and hand searches and cross-referencing performed. Fourteen (mainly observational) studies were included. Ten trials (381 participants) investigated MIH-molars, four (139) MIH-incisors. For molars, remineralization, restorative or extraction therapies had been assessed. For restorative approaches, mean (SD) annual failure rates were highest for fissure sealants (12[6]%) and glass-ionomer restorations (12[2]%), and lowest for indirect restorations (1[3]%), preformed metal crowns (1.3 [2.1]%) and composite restorations (4[3]%). Ony study assessed extraction of molars in young patients (median age 8.2 years), the majority of them without malocclusions, but third molars in development. Spontaneous alignment of second molars was more frequent in the maxilla (55%) than the mandible (47%). For incisors, desensitizing agents successfully managed hypersensitivity. Micro-abrasion and composite veneers improved aesthetics. Few, mainly moderate to high-risk-studies investigated treatment of MIH. Remineralization or sealants seem suitable for MIH-molars with limited severity and/or hypersensitivity. For severe cases, restorations with composites or indirect restorations or preformed metal crowns seem suitable. Prior to tooth extraction as last resort factors like the presence of a general malocclusion, patients' age and the status of neighboring teeth should be considered. No recommendations can be given for MIH-incisors. Dentists need to consider the specific condition of each tooth and the needs and expectations of

  6. Fusion or gemination? An unusual mandibular second molar

    Directory of Open Access Journals (Sweden)

    Angela Jordão Camargo

    2016-01-01

    Full Text Available Fusion and gemination is not an uncommon finding and affected most primary dentition and the permanent maxillary incisors. These changes can develop a series of complication. A 11-year-old male presented radiography finding: an unusual mandibular second molar. A well-documented case brings a challenge for radiologists classify between fusion and gemination. In conclusion, this alteration although common in other regions, there are no case in the literature involving “second and third” molar.

  7. Anxiety before extraction of impacted lower third molars

    OpenAIRE

    Tarazona Álvarez, Beatriz; Tarazona Álvarez, Pablo; Peñarrocha Oltra, David; Rojo Moreno, Juan; Peñarrocha Diago, María

    2015-01-01

    Objetives: Assess levels of trait anxiety, state anxiety and dental anxiety before extraction of lower third molars and check the correlation and reliability of the scales used for the measurement of preoperative anxiety. Study Design: A prospective study of patients treated with extraction of a lower third molar between September 2010 to December 2010 was carried out. A total of 125 patients were included in the study. All of them were patients of the Oral Surgery and Implantology Department...

  8. A retrospective study of sodium hypochlorite pulpotomies in primary molars

    OpenAIRE

    Li, Tzu-Ying; Chuang, Li-Chuan; Aileen I Tsai

    2016-01-01

    Background/purpose: Formocresol has been a popular pulpotomy medicament for primary molars, however, its toxicity and potential carcinogenicity leaves room for other alternatives such as sodium hypochlorite (NaOCl). The purpose of this study is to evaluate the clinical and radiographic success rate of 5% NaOCl pulpotomy in primary molars. Materials and methods: A retrospective research of patient records from January 1, 2009 and December 31, 2012 was conducted to evaluate the clinical and ...

  9. Molar Absorptivities of Ultraviolet and Visible Bands of Ozone in Aqueous Solutions

    DEFF Research Database (Denmark)

    Hart, E.J.; Sehested, Knud; Holcman, J.

    1983-01-01

    by absorbance measurements of the gas at 253.7 nm and by oxidation of FeSO4 in H2SO4 solution followed by back-titration of excess Fe2+ with KMnO4. Spectrophotometric analysis of Fe3+ was also used at low ozone concentrations. A stoichiometric ratio, Fe3+/O3, of 1.996 .+-. 0.036 was found. The visible spectrum......The molar absorptivities of aqueous ozone solutions [.epsilon.(O3)] are reported for the wavelength ranges 190-300 nm and 350-900 nm. At the maxima of these bands, .epsilon.260(O3) = 3292 .+-. 70 M-1 cm-1 and .epsilon.590(O3) = 5.1 .+-. 0.1 M-1 cm-1. The analyses for ozone were carried out...... of aqueous O3 is compared with that of ozone gas....

  10. Excessive libido in a woman with rabies.

    OpenAIRE

    Dutta, J. K.

    1996-01-01

    Rabies is endemic in India in both wildlife and humans. Human rabies kills 25,000 to 30,000 persons every year. Several types of sexual manifestations including excessive libido may develop in cases of human rabies. A laboratory proven case of rabies in an Indian woman who manifested excessive libido is presented below. She later developed hydrophobia and died.

  11. Understand Your Risk for Excessive Blood Clotting

    Science.gov (United States)

    ... Vascular Health Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Understand Your Risk for Excessive Blood Clotting Updated:Nov 2,2015 Many factors can lead to excessive blood clotting, leading to limited or blocked blood flow. Blood clots can travel to the arteries or ...

  12. Bladder calculus presenting as excessive masturbation.

    Science.gov (United States)

    De Alwis, A C D; Senaratne, A M R D; De Silva, S M P D; Rodrigo, V S D

    2006-09-01

    Masturbation in childhood is a normal behaviour which most commonly begins at 2 months of age, and peaks at 4 years and in adolescence. However excessive masturbation causes anxiety in parents. We describe a boy with a bladder calculus presenting as excessive masturbation.

  13. 30 CFR 57.6902 - Excessive temperatures.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Excessive temperatures. 57.6902 Section 57.6902... Requirements-Surface and Underground § 57.6902 Excessive temperatures. (a) Where heat could cause premature... shall— (1) Measure an appropriate number of blasthole temperatures in order to assess the specific mine...

  14. 30 CFR 56.6902 - Excessive temperatures.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Excessive temperatures. 56.6902 Section 56.6902... Requirements § 56.6902 Excessive temperatures. (a) Where heat could cause premature detonation, explosive... an appropriate number of blasthole temperatures in order to assess the specific mine conditions prior...

  15. Excess Based Allocation of Risk Capital

    NARCIS (Netherlands)

    van Gulick, G.; De Waegenaere, A.M.B.; Norde, H.W.

    2010-01-01

    In this paper we propose a new rule to allocate risk capital to portfolios or divisions within a firm. Specifically, we determine the capital allocation that minimizes the excesses of sets of portfolios in lexicographical sense. The excess of a set of portfolios is defined as the expected loss of

  16. The excessively crying infant : etiology and treatment

    NARCIS (Netherlands)

    Akhnikh, S.; Engelberts, A.C.; Sleuwen, B.E. van; Hoir, M.P. L’; Benninga, M.A.

    2014-01-01

    Excessive crying, often described as infantile colic, is the cause of 10% to 20% of all early pediatrician visits of infants aged 2 weeks to 3 months. Although usually benign and selflimiting, excessive crying is associated with parental exhaustion and stress. However, and underlying organic cause

  17. Triboson interpretations of the ATLAS diboson excess

    CERN Document Server

    Aguilar-Saavedra, J.A.

    2015-01-01

    The ATLAS excess in fat jet pair production is kinematically compatible with the decay of a heavy resonance into two gauge bosons plus an extra particle. This possibility would explain the absence of such a localised excess in the analogous CMS analysis of fat dijet final states, as well as the negative results of diboson resonance searches in the semi-leptonic decay modes.

  18. Accurate Gas Phase Formation Enthalpies of Alloys and Refractories Decomposition Products.

    Science.gov (United States)

    Minenkov, Yury; Sliznev, Valery V; Cavallo, Luigi

    2017-02-06

    Accurate gas phase formation enthalpies, ΔHf, of metal oxides and halides are critical for the prediction of the stability of high temperature materials used in the aerospace and nuclear industries. Unfortunately, the experimental ΔHf values of these compounds in the most used databases, such as the NIST-JANAF database, are often reported with large inaccuracy, while some other ΔHf values clearly differ from the value predicted by CCSD(T) methods. To address this point, in this work we systematically predicted the ΔHf values of a series of these compounds having a group 4, 6, or 14 metal. The ΔHf values in question were derived within a composite Feller-Dixon-Peterson (FDP) scheme based protocol that combines the DLPNO-CCSD(T) enthalpy of ad hoc designed reactions and the experimental ΔHf values of few reference complexes. In agreement with other theoretical studies, we predict the ΔHf values for TiOCl2, TiOF2, GeF2, and SnF4 to be significantly different from the values tabulated in NIST-JANAF and other sources, which suggests that the tabulated experimental values are inaccurate. Similarly, the predicted ΔHf values for HfCl2, HfBr2, HfI2, MoOF4, MoCl6, WOF4, WOCl4, GeO2, SnO2, PbBr4, PbI4, and PbO2 also clearly differ from the tabulated experimental values, again suggesting large inaccuracy in the experimental values. In the case when largely different experimental values are available, we point to the value that is in better agreement with our results. We expect the ΔHf values reported in this work to be quite accurate, and thus, they might be used in thermodynamic calculations, because the effects from core correlation, relativistic effects, and basis set incompleteness were included in the DLPNO-CCSD(T) calculations. T1 and T2 values were thoroughly monitored as indicators of the quality of the reference Hartree-Fock orbitals (T1) and potential multireference character of the systems (T2).

  19. Charged de Sitter-like black holes: quintessence-dependent enthalpy and new extreme solutions

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Ainou, Mustapha [Baskent University, Faculty of Engineering, Ankara (Turkey)

    2015-01-01

    We consider Reissner-Nordstroem black holes surrounded by quintessence where both a non-extremal event horizon and a cosmological horizon exist besides an inner horizon (-1 ≤ ω < -1/3). We determine new extreme black hole solutions that generalize the Nariai horizon to asymptotically de Sitter-like solutions for any order relation between the squares of the charge q{sup 2} and the mass parameter M{sup 2} provided q{sup 2} remains smaller than some limit, which is larger than M{sup 2}. In the limit case q{sup 2} = 9ω{sup 2}M{sup 2}/(9ω{sup 2}-1), we derive the general expression of the extreme cosmo-blackhole, where the three horizons merge, and we discuss some of its properties.We also show that the endpoint of the evaporation process is independent of any order relation between q{sup 2} and M{sup 2}. The Teitelboim energy and the Padmanabhan energy are related by a nonlinear expression and are shown to correspond to different ensembles. We also determine the enthalpy H of the event horizon, as well as the effective thermodynamic volume which is the conjugate variable of the negative quintessential pressure, and show that in general the mass parameter and the Teitelboim energy are different from the enthalpy and internal energy; only in the cosmological case, that is, for Reissner-Nordstroem-de Sitter black hole we have H = M. Generalized Smarr formulas are also derived. It is concluded that the internal energy has a universal expression for all static charged black holes, with possibly a variable mass parameter, but it is not a suitable thermodynamic potential for static-black-hole thermodynamics if M is constant. It is also shown that the reverse isoperimetric inequality holds. We generalize the results to the case of the Reissner-Nordstroem-de Sitter black hole surrounded by quintessence with two physical constants yielding two thermodynamic volumes. (orig.)

  20. Accurate Gas Phase Formation Enthalpies of Alloys and Refractories Decomposition Products

    KAUST Repository

    Minenkov, Yury

    2017-01-17

    Accurate gas phase formation enthalpies, ΔHf, of metal oxides and halides are critical for the prediction of the stability of high temperature materials used in the aerospace and nuclear industries. Unfortunately, the experimental ΔHf values of these compounds in the most used databases, such as the NIST-JANAF database, are often reported with large inaccuracy, while some other ΔHf values clearly differ from the value predicted by CCSD(T) methods. To address this point, in this work we systematically predicted the ΔHf values of a series of these compounds having a group 4, 6, or 14 metal. The ΔHf values in question were derived within a composite Feller-Dixon-Peterson (FDP) scheme based protocol that combines the DLPNO-CCSD(T) enthalpy of ad hoc designed reactions and the experimental ΔHf values of few reference complexes. In agreement with other theoretical studies, we predict the ΔHf values for TiOCl2, TiOF2, GeF2, and SnF4 to be significantly different from the values tabulated in NIST-JANAF and other sources, which suggests that the tabulated experimental values are inaccurate. Similarly, the predicted ΔHf values for HfCl2, HfBr2, HfI2, MoOF4, MoCl6, WOF4, WOCl4, GeO2, SnO2, PbBr4, PbI4, and PbO2 also clearly differ from the tabulated experimental values, again suggesting large inaccuracy in the experimental values. In the case when largely different experimental values are available, we point to the value that is in better agreement with our results. We expect the ΔHf values reported in this work to be quite accurate, and thus, they might be used in thermodynamic calculations, because the effects from core correlation, relativistic effects, and basis set incompleteness were included in the DLPNO-CCSD(T) calculations. T1 and T2 values were thoroughly monitored as indicators of the quality of the reference Hartree-Fock orbitals (T1) and potential multireference character of the systems (T2).

  1. Prevalence of Taurodont molars in a North Indian population.

    Science.gov (United States)

    Bharti, Ramesh; Chandra, Anil; Tikku, Aseem Prakash; Arya, Deeksha

    2015-01-01

    It is very important for dentists to be familiar with anomalies of teeth not only for the clinical complications but also their management. Taurodontism also provides a valuable clue in detecting its association with various syndromes and other systemic conditions. The purpose of this study was to assess the prevalence of Taurodont molars among a North Indian population. A total of 1000 patients' full-mouth periapical radiographs were screened. The radiographs were evaluated under optimal conditions using double magnifying glasses. A total of 7615 molars (including third molars) were evaluated. The relative incidence and the correlations regarding the location of Taurodont teeth (right versus left side and maxillary versus mandibular) were analyzed using the Chi-square test. Twenty-eight patients were found to have a Taurodont molar (11 women and 17 men [P = 0.250]). The prevalence of Taurodont molar was 2.8%. Males had a higher prevalence rate than females (3.4% vs. 2.2%, respectively). A cluster analysis of total Taurodonts in the mandible (45%) versus maxilla (55%) of both males and females combined showed a statistically significant difference (P Taurodontism is basically based on racial expression in different populations. These variations in prevalence between different populations may be due to ethnic variations. The occurrence of Taurodont molars among this Indian population was rare.

  2. Cuartos molares supernumerarios: relato de caso clínico

    Directory of Open Access Journals (Sweden)

    Daniela Nascimento Silva

    2006-04-01

    Full Text Available Los dientes supernumerarios se diagnostican mediante exámenes radiográficos de rutina, pues generalmente son asintomáticos. Los cuartos molares representan el segundo grupo de dientes supernumerarios con más frecuencias; ocurren en posición distal a los terceros molares, especialmente en el maxilar superior, y en la mayoría de casos, estos están incluidos. El objetivo de este artículo es realizar la presentación de un caso, de una mujer de 30 anos con los cuartos molares incluidos en el maxilar inferior y describir la técnica para su remoción.Supernumerary teeth are generally asymptomatic and are diagnosed by routine X-ray tests. The fourth molar teeth represent the second group of the most frequent supernumerary teeth, occur in distal position to the third molar teeth, specially in the superior maxilla and, in most of the cases, they are included. The aim of this paper is to comment on the case of a 30-year-old woman with the fourth molar teeth included in the inferior maxilla and to describe the technique used for their removal.

  3. Caries Management Strategies for Primary Molars

    Science.gov (United States)

    Santamaria, R.M.; Innes, N.P.T.; Machiulskiene, V.; Evans, D.J.P.; Splieth, C.H.

    2014-01-01

    Minimal invasive approaches to managing caries, such as partial caries removal techniques, are showing increasing evidence of improved outcomes over the conventional complete caries removal. There is also increasing interest in techniques where no caries is removed. We present the 1-yr results of clinical efficacy for 3 caries management options for occlusoproximal cavitated lesions in primary molars: conventional restorations (CR; complete caries removal and compomer restoration), Hall technique (HT; no caries removal, sealing in with stainless steel crowns), and nonrestorative caries treatment (NRCT; no caries removal, opening up the cavity, teaching brushing and fluoride application). In sum, 169 children (3-8 yr old; mean, 5.56 ± 1.45 yr) were enrolled in this secondary care–based, 3-arm, parallel-group, randomized clinical trial. Treatments were carried out by specialist pediatric dentists or postgraduate trainees. One lesion per child received CR, HT, or NRCT. Outcome measures were clinical failure rates, grouped as minor failure (restoration loss/need for replacement, reversible pulpitis, caries progression, etc.) and major failure (irreversible pulpitis, abscess, etc.). There were 148 children (87.6%) with a minimum follow-up of 11 mo (mean, 12.23 ± 0.98 mo). Twenty teeth were recorded as having at least 1 minor failure: NRCT, n = 8 (5%); CR, n = 11 (7%); HT, n = 1 (1%) (p = .002, 95% CI = 0.001 to 0.003). Only the comparison between NRCT and CR showed no significant difference (p = .79, 95% CI = 0.78 to 0.80). Nine (6%) experienced at least 1 major failure: NRCT, n = 4 (2%); CR, n = 5 (3%); HT, n = 0 (0%) (p = .002, 95% CI = 0.001 to 0.003). Individual comparison of NRCT and CR showed no statistically significant difference in major failures (p = .75, 95% CI = 0.73 to 0.76). Success and failure rates were not significantly affected by pediatric dentists’ level of experience (p = .13, 95% CI = 0.12 to 0.14). The HT was significantly more successful

  4. Pressão interna e refração molar dos sistemas dimetilsulfóxido + tiofeno, dimetilsulfóxido + piridina a 298,15K

    OpenAIRE

    AZNAREZ, Silvia Beatriz; POSTIGO, Miguel Ángelo; MARTINS, Adair

    1999-01-01

    Pressão interna, volume livre, refração molar e propriedades termodinâmicas de excesso de misturas líquidas binárias de dimetil sulfóxido + tiofeno e dimetil sulfóxido + piridina a 298.15K foram calculadas a partir de medidas experimentais de densidades, tensão superficial e índice de refração. A relação entre a pressão interna, volume molar de excesso, refração molar, e a interação molecular dos sistemas binários é examinada. Internal pressure, free volume, molar refraction and excess mol...

  5. Prevalence of missing and impacted third molars in adults aged 25 years and above

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yun Hoa; Cho, Bong Hae [Dept. of Oral and Maxillofacial Radiology, School of Dentistry, Pusan National University, Yansan (Korea, Republic of)

    2013-12-15

    The purpose of this study was to determine the prevalence of missing and impacted third molars in people aged 25 years and above. The study sample of 3,799 patients was chosen randomly from patients who visited Pusan National University Dental Hospital and had panoramic radiographs taken. The data collected included presence and impaction state, angulation, and depth of impaction of third molars, and radiographically detected lesions of third molars and adjacent second molars. A greater percentage of men than women retained at least one third molar. The incidence of third molars decreased with increasing age. The incidence of partially impacted third molars greatly declined after the age of 30. Vertically impacted maxillary third molars and horizontally impacted mandibular third molars were most frequent in all age groups. Among the maxillary third molars, those impacted below the cervical line of the second molar were most frequent in all age groups, and among the mandibular third molars, deeply impacted third molars were most frequent in those aged over 40. Dental caries was the most common radiographic lesion of the third molars. Mesioangularly impacted third molars showed radiographic lesions in 13 (9.5%) adjacent maxillary second molars and 117 (27.4%) mandibular second molars. The number of remaining third molars decreased and the percentage of Class C depth increased with age. Caries was the most frequent lesion in third molars. Partially impacted mesioangular third molars showed a high incidence of caries or periodontal bone loss of the adjacent second molar. Regular oral examination will be essential to keep asymptomatic third molars in good health.

  6. Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: Variation within species and relevance to risk communication

    Science.gov (United States)

    Burger, Joanna; Gochfeld, Michael

    2015-01-01

    There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 may be at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others. PMID:23541437

  7. Two-year follow-up of indirect posterior composite restorations of permanent teeth with excessive material loss in pediatric patients: a clinical study.

    Science.gov (United States)

    Koyuturk, Alp Erdin; Ozmen, Bilal; Tokay, Ugur; Tuloglu, Nuray; Sari, M Erhan; Sonmez, T Taha

    2013-12-01

    To evaluate the clinical effectiveness of indirect composite restorations in permanent molars with excessive substance loss in pediatric patients who have undergone root canal treatments. Molars of 29 pediatric patients underwent endodontic treatment. Sixteen molars were restored with an indirect posterior composite resin restoration and 13 molars were restored with a direct posterior composite resin restoration. The success of the restorations was evaluated for 2 years based on United States Public Health Service (USPHS) criteria, photographs after staining with basic fuchsine, and radiographic data. Data obtained from both groups were compared using the Mann-Whitney U-test and Wilcoxon signed rank test. Evaluation of the clinical and radiographic data revealed no observable, statistically significant differences between the posterior and the indirect posterior composites (p > 0.05). However, evaluation of photos taken of the patients' molars after staining with basic fuchsin revealed that direct posterior composites showed increased staining on the margins of the restorations after six months (p restoring endodontically treated permanent teeth with excessive substance loss in child patients, indirect restorations may be seen as a better option.

  8. Systematic search for low-enthalpy sp3 carbon allotropes using evolutionary metadynamics

    Science.gov (United States)

    Zhu, Qiang; Zeng, Qingfeng; Oganov, Artem R.

    2012-05-01

    We present a systematic search for low-energy metastable superhard carbon allotropes by using the recently developed evolutionary metadynamics technique. It is known that cold compression of graphite produces an allotrope at 15-20 GPa. Here we look for all low-enthalpy structures accessible from graphite. Starting from 2H- or 3R-graphite and applying a pressure of 20 GPa, a large variety of intermediate sp3 carbon allotropes were observed in evolutionary metadynamics simulation. Our calculation not only found all the previous proposed candidates for “superhard graphite,” but also predicted two allotropes (X-carbon and Y-carbon) showing unusual types of 5+7 and 4+8 topologies. These superhard carbon allotropes can be classified into five families based on 6 (diamond/lonsdaleite), 5+7 (M- and W-carbon), 5+7 (X-carbon), 4+8 (bct-C4), and 4+8 (Y-carbon) topologies. This study shows that evolutionary metadynamics is a powerful approach both to find the global minima and systematically search for low-energy metastable phases reachable from given starting materials.

  9. Blunt-Body Aerothermodynamic Database from High-Enthalpy CO2 Testing in an Expansion Tunnel

    Science.gov (United States)

    Hollis, Brian R.; Prabhu, Dinesh K.; Maclean, Matthew; Dufrene, Aaron

    2016-01-01

    An extensive database of heating, pressure, and flow field measurements on a 70-deg sphere-cone blunt body geometry in high-enthalpy, CO2 flow has been generated through testing in an expansion tunnel. This database is intended to support development and validation of computational tools and methods to be employed in the design of future Mars missions. The test was conducted in an expansion tunnel in order to avoid uncertainties in the definition of free stream conditions noted in previous studies performed in reflected shock tunnels. Data were obtained across a wide range of test velocity/density conditions that produced various physical phenomena of interest, including laminar and transitional/turbulent boundary layers, non-reacting to completely dissociated post-shock gas composition and shock-layer radiation. Flow field computations were performed at the test conditions and comparisons were made with the experimental data. Based on these comparisons, it is recommended that computational uncertainties on surface heating and pressure, for laminar, reacting-gas environments can be reduced to +/-10% and +/-5%, respectively. However, for flows with turbulence and shock-layer radiation, there were not sufficient validation-quality data obtained in this study to make any conclusions with respect to uncertainties, which highlights the need for further research in these areas.

  10. Enthalpy, Geometric Volume and Logarithmic correction to Entropy for Van-der-Waals Black Hole

    CERN Document Server

    Pradhan, Parthapratim

    2016-01-01

    If the negative cosmological constant is treated as a dynamical pressure and if the volume be its thermodynamically conjugate variable then the gravitational mass can be expressed as the total gravitational enthalpy rather than the energy. Under these circumstances, a new phenomena emerges in the context of extended phase space thermodynamics. We \\emph{examine} here these features for recently discovered Van-der-Waal (VDW) black hole (BH) \\cite{mann15} which is analogous to the VDW fluid. We show that the thermodynamic volume is \\emph{greater} than the naive geometric volume. We also show that the \\emph{Smarr-Gibbs-Duhem} relation is satisfied for this BH. Furthermore, by computing the thermal specific heat we find the local thermodynamic stability criterion for this BH. It has been observed that the BH does \\emph{not} possess any kind of second order phase transition. This is an interesting feature of VDW BH by its own right. Moreover, we also derive \\emph{Cosmic-Censorship-Inequality} for this class of BH. ...

  11. Analysis of experimental routines of high enthalpy steam discharge in subcooled water

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, Rafael R., E-mail: Rafael.rade@ctmsp.mar.mil.br [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), SP (Brazil); Andrade, Delvonei A., E-mail: delvonei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The discharge of high enthalpy steam through safety release valves out from pressurizers in PWR's needs to be condensed in order to allow the treatment of possibly present radwaste within. The Direct Contact Condensation is used in a relief tank to achieve the condensation. Care must be taken to avoid the bypass of the steam through the subcooled water, what would increase the peak of pressure and the necessity of structural reinforcement of the relief tank. An experiment to determine the optimal set up of the relief tank components and their characteristics (type of sprinkler, level of water, volume of tank, discharge direction, pressure in the pressurizer among others) was executed in 2000, in the CTE 150 facility, in CTMSP. In a total, 144 routines varying its components and characteristics were made, although no comprehensive analysis of its results were yet made, since the mass of data was too big to be readily analyzed. In order to comprehensively analyze it, a VBA program is being made to compile and graphically represent the mass of data. The current state of this program allowed conclusions over the peak pressure, adiabatic assumption of the experiment, and the quality of the steam generated due to the discharge. (author)

  12. A Non-Isothermal Chemical Lattice Boltzmann Model Incorporating Thermal Reaction Kinetics and Enthalpy Changes

    Directory of Open Access Journals (Sweden)

    Stuart Bartlett

    2017-08-01

    Full Text Available The lattice Boltzmann method is an efficient computational fluid dynamics technique that can accurately model a broad range of complex systems. As well as single-phase fluids, it can simulate thermohydrodynamic systems and passive scalar advection. In recent years, it also gained attention as a means of simulating chemical phenomena, as interest in self-organization processes increased. This paper will present a widely-used and versatile lattice Boltzmann model that can simultaneously incorporate fluid dynamics, heat transfer, buoyancy-driven convection, passive scalar advection, chemical reactions and enthalpy changes. All of these effects interact in a physically accurate framework that is simple to code and readily parallelizable. As well as a complete description of the model equations, several example systems will be presented in order to demonstrate the accuracy and versatility of the method. New simulations, which analyzed the effect of a reversible reaction on the transport properties of a convecting fluid, will also be described in detail. This extra chemical degree of freedom was utilized by the system to augment its net heat flux. The numerical method outlined in this paper can be readily deployed for a vast range of complex flow problems, spanning a variety of scientific disciplines.

  13. Computational modelling of the gas flow from a high-enthalpy blast simulator

    Science.gov (United States)

    Edwards, D. G.; Phan, K. C.; Hurdle, C. V.

    1990-07-01

    An Eulerian computer code based on the Flux-Corrected Transport algorithm has been develped to model the flow within and in the immediate vicinity of the RARDE (UK) High-Enthalpy Blast Simulator. The code incorporates a fully-second-order solution-scheme incorporating operator-splitting in the solution of multi-dimensional time-dependent flows. The computing mesh has been refined to make efficient use of the limited computing memory and processing power available to this project. The flow is one-dimensional in much the greater part of the facility: two-dimensional axi-symmetric flow is confined to the junctions between long tubes of constant diameter, and the computing mesh is configured accordingly. Early runs of the code have been based on a coarse computing mesh, for reasons of expedinency. Even so, results to date have confirmed may of the qualitative predictions concerning the behavior of the HEBSIM; comparisons with existing experimental data on wall-pressure histories at various stations within the facility show an encouraging measure of accord. Later runs will feature a more refined mesh, and it is hoped that design-recommendations will result from this more-realistic simulation exercise as an aid to the further developement of the HEBSIM facility.

  14. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.

    1990-08-31

    The need for highly accurate thermal property data for a broad range of new application fluids is well documented. To facilitate expansion of the current thermophysical database, an automated flow calorimeter was developed for the measurement of highly accurate isobaric heat capacities and enthalpies of fluids at elevated temperatures and pressures. The experimental technique utilizes traditional electrical power input, adiabatic flow calorimetry with a precision metering pump that eliminates the need for on-line flow rate monitoring. In addition, a complete automation system, greatly simplifies the operation of the apparatus and increases the rapidity of the measurement process. The range over which the instrument was tested, was 300--600 K and 0--12 Mpa, although the calorimeter should perform up to the original design goals of 700 K and 30 MPa. The new flow calorimeter was evaluated by measuring the mean, isobaric, specific heat capacities of liquid water and n-pentane. These experiments yielded an average deviation from the standard literature data of +0.02% and a total variation of 0.05%. Additional data analysis indicated that the overall measurement uncertainty was conservatively estimated as 0.2% with an anticipated precision of 0.1--0.15% at all operating conditions. 44 refs., 27 figs., 2 tabs.

  15. A Multichannel Calorimetric Simultaneous Assay Platform Using a Microampere Constant-Current Looped Enthalpy Sensor Array

    Directory of Open Access Journals (Sweden)

    Hsien-Chin Wei

    2017-02-01

    Full Text Available Calorimetric biochemical measurements offer various advantages such as low waste, low cost, low sample consumption, short operating time, and labor-savings. Multichannel calorimeters can enhance the possibility of performing higher-throughput biochemical measurements. An enthalpy sensor (ES array is a key device in multichannel calorimeters. Most ES arrays use Wheatstone bridge amplifiers to condition the sensor signals, but such an approach is only suitable for null detection and low resistance sensors. To overcome these limitations, we have developed a multichannel calorimetric simultaneous assay (MCSA platform. An adjustable microampere constant-current (AMCC source was designed for exciting the ES array using a microampere current loop measurement circuit topology. The MCSA platform comprises a measurement unit, which contains a multichannel calorimeter and an automatic simultaneous injector, and a signal processing unit, which contains multiple ES signal conditioners and a data processor. This study focused on the construction of the MCSA platform; in particular, construction of the measurement circuit and calorimeter array in a single block. The performance of the platform, including current stability, temperature sensitivity and heat sensitivity, was evaluated. The sensor response time and calorimeter constants were given. The capability of the platform to detect relative enzyme activity was also demonstrated. The experimental results show that the proposed MCSA is a flexible and powerful biochemical measurement device with higher throughput than existing alternatives.

  16. REDUCTION OF ENTHALPY RELAXATION IN GELATINE FILMS BY ADDITION OF POLYOLS.

    Science.gov (United States)

    Díaz-Calderón, Paulo; MacNaughtan, Bill; Hill, Sandra; Mitchell, John; Enrione, Javier

    2017-12-16

    The aim of this study was to evaluate the effect of plasticisers with different molecular weights (glycerol and sorbitol) on the structural relaxation kinetics of bovine gelatine films stored under the glass transition temperature (Tg). Plasticisers were tested at weight fractions of 0.0, 0.06 and 0.10. Films conditioned in environments under ∼44% relative humidity gave moisture contents (w/w) in the range 0.14-0.18. The enthalpy relaxation (ΔH) was determined using differential scanning calorimetry (DSC). Samples used had Tg values in the range 24-49 °C. After removing the thermal history (30 °C above Tg, 15 minutes), samples were isothermally stored at 10 °C below Tg for between 2-80 hours. The addition of plasticisers induced a significant reduction in the rate of structural relaxation. The linearisation of ΔH by plotting against the logarithm of ageing time showed a reduction in the slope of samples plasticised with both polyols. The reduction in relaxation kinetics may be related to the ability of polyols to act as enhancers of molecular packing, as recently reported using positron spectroscopy (PALS). However, a direct correlation between the relaxation kinetics and the plasticiser's molecular weight could not be established, suggesting that this phenomenon may be governed by complex molecular gelatin-plasticiser-water interactions. Copyright © 2017. Published by Elsevier B.V.

  17. The C-H bond dissociation enthalpies in fused N-heterocyclic compounds

    Science.gov (United States)

    Wang, Ying-Xing; Zheng, Wen-Rui; Ding, Lan-Lan

    2016-03-01

    The C-H bond dissociation enthalpies (BDEs) of the 26 N, O, S-containing mono-heterocyclic compounds were evaluated using the composite high-level ab initio methods G3 and G4. The C-H BDEs for 32 heterocyclic compounds were calculated using 8 types of density functional theory (DFT) methods. Comparing with the experimental values, the BMK method gave the lowest root mean square error (RMSE) of 7.2 kJ/mol. Therefore, the C-H BDEs of N-fused-heterocyclic compounds at different positions were investigated by the BMK method. By NBO analysis two linear relationships between the C-H BDEs of quinoline and isoquinoline with natural charges qC/ e in molecules and with natural charges qC/ e in radicals were found. The substituent effects on C(α)-H BDEs in N-fused-heterocyclic compounds were also discussed. It was found that there are two linear relationships between the C(α)-H BDEs of quinoline and isoquinoline derivatives with natural charges qC(α)/ e for the EDGs and CEGs substituents.

  18. Orthodontic Replacement of Lost Permanent Molar with Neighbor Molar: A Six-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Taisa Boamorte Raveli

    2017-01-01

    Full Text Available Extraction is very frequent indication in orthodontic planning, especially when there are crowding, biprotrusion, and aesthetically unpleasant profiles. Next to extraction comes space closure, which represents a challenge for orthodontists because of extended treatment time, discomfort created for the patient, tissue tolerance, and stability concerns. When it comes to what mechanics to choose for space closure, loops present two major advantages in relation to sliding mechanics: absence of abrasion and possibility to reach pure dental translation. A case is presented where an adult female patient with early loss of the first lower permanent molars, minor lower crowding, and tooth biprotrusion was treated with upper first bicuspids extraction along with upper and lower space closure done with T-loops to promote best space closure control in order to correct the malocclusion and enhance facial aesthetics.

  19. 26 CFR 54.4979-1 - Excise tax on certain excess contributions and excess aggregate contributions.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Excise tax on certain excess contributions and excess aggregate contributions. 54.4979-1 Section 54.4979-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) MISCELLANEOUS EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4979-1 Excise tax on certain excess...

  20. Pattern of third molar impaction in a Saudi population

    Directory of Open Access Journals (Sweden)

    Ali H Hassan

    2010-10-01

    Full Text Available Ali H Hassan11Department of Preventive Dental Sciences, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi ArabiaObjective: To evaluate the current pattern of third molar impaction in a sample of Saudi patients.Methods: One thousand thirty-nine orthopantomograms (OPG of patients ranging in age from 19 to 46 years (536 males and 503 females were evaluated to determine the frequency of impacted third molars, their levels of eruption, and their angulations.Results: Four hundred twenty-two (40.5% of the 1039 OPG showed at least one impacted third molar, with no significant difference between males (222; 52.6% and females (200; 47.4% (P = 0.284. The most common number of impacted third molars per OPG was one (72.5%. Impacted third molars were 1.64 times more likely to occur in the mandible than in the maxilla. The most common angulation of impaction in the mandible was the mesial (33.4%, while the most common angulation in the maxilla, was the vertical (49.6%. Level B impaction was the most common in both maxilla (48.2% and mandible (67.7%. There was no significant difference in the frequency of impaction between the right and left sides in both jaws.Conclusion: The pattern of third molar impaction in the western region of Saudi Arabia is characterized by a high prevalence of impaction that is greater in the mandibles and with no sex predilection.Keywords: third molar, impaction, prevalence, Saudi 

  1. Predictors of excessive use of social media and excessive online gaming in Czech teenagers.

    Science.gov (United States)

    Spilková, Jana; Chomynová, Pavla; Csémy, Ladislav

    2017-12-01

    Background and aims Young people's involvement in online gaming and the use of social media are increasing rapidly, resulting in a high number of excessive Internet users in recent years. The objective of this paper is to analyze the situation of excessive Internet use among adolescents in the Czech Republic and to reveal determinants of excessive use of social media and excessive online gaming. Methods Data from secondary school students (N = 4,887) were collected within the 2015 European School Survey Project on Alcohol and Other Drugs. Logistic regression models were constructed to describe the individual and familial discriminative factors and the impact of the health risk behavior of (a) excessive users of social media and (b) excessive players of online games. Results The models confirmed important gender-specific distinctions - while girls are more prone to online communication and social media use, online gaming is far more prevalent among boys. The analysis did not indicate an influence of family composition on both the excessive use of social media and on excessive online gaming, and only marginal effects for the type of school attended. We found a connection between the excessive use of social media and binge drinking and an inverse relation between excessive online gaming and daily smoking. Discussion and conclusion The non-existence of significant associations between family environment and excessive Internet use confirmed the general, widespread of this phenomenon across the social and economic strata of the teenage population, indicating a need for further studies on the topic.

  2. Evaluation of the Gibbs Free Energy Changes and Melting Temperatures of DNA/DNA Duplexes Using Hybridization Enthalpy Calculated by Molecular Dynamics Simulation.

    Science.gov (United States)

    Lomzov, Alexander A; Vorobjev, Yury N; Pyshnyi, Dmitrii V

    2015-12-10

    A molecular dynamics simulation approach was applied for the prediction of the thermal stability of oligonucleotide duplexes. It was shown that the enthalpy of the DNA/DNA complex formation could be calculated using this approach. We have studied the influence of various simulation parameters on the secondary structure and the hybridization enthalpy value of Dickerson-Drew dodecamer. The optimal simulation parameters for the most reliable prediction of the enthalpy values were determined. The thermodynamic parameters (enthalpy and entropy changes) of a duplex formation were obtained experimentally for 305 oligonucleotides of various lengths and GC-content. The resulting database was studied with molecular dynamics (MD) simulation using the optimized simulation parameters. Gibbs free energy changes and the melting temperatures were evaluated using the experimental correlation between enthalpy and entropy changes of the duplex formation and the enthalpy values calculated by the MD simulation. The average errors in the predictions of enthalpy, the Gibbs free energy change, and the melting temperature of oligonucleotide complexes were 11%, 10%, and 4.4 °C, respectively. We have shown that the molecular dynamics simulation gives a possibility to calculate the thermal stability of native DNA/DNA complexes a priori with an unexpectedly high accuracy.

  3. Enthalpy measurement of coal-derived liquids. Final report, April 1981-September 1983. [517 to 10342 kPa; 340 to 664 K

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1983-11-10

    This report summarizes the results of experimental measurements of enthalpies for quinoline using a freon boil-off flow calorimeter, and an investigation of the applicability of cubic equations of state to correlating the enthalpy of coal-liquids. In Part A the compound quinoline is discussed. Process flow in the flow calorimeter, operational problems, and equipment modifications are described. Procedural modifications, including a new sample purification procedure, are described. Part B discusses the correlational effort. This includes a discussion of past correlational work and the difficulties associated with a general correlation for coal liquid enthalpy. In addition experimental data and computer generated predictions are presented. Three equations of state were used to predict vapor pressures and enthalpies for ten pure component systems previously studied in the lab. In general, the results were encouraging. All three equations were found to be effective in predicting both enthalpies and vapor pressures. In addition, the equations worked well when fit to mixture enthalpies. The Modified SRK equation was found to be superior to the other equations and modeled all properties for both associating and nonassociating systems well. The Modified SRK equation did have a drawback in that it was not readily generalized since it required two parameters which must be fit to data for best results. In sum, it was shown that a four parameter equation of state could be used successfully to correlate the enthalpy of coal-liquid model compounds.

  4. Excess properties of Lennard-Jones binary mixtures from computer simulation and theory

    Science.gov (United States)

    Blas, Felipe J.; Fujihara, Ichiro

    Monte Carlo simulation and theory are used to calculate the excess thermodynamic properties of binary mixtures of spherical Lennard-Jones molecules. We study the excess functions of three binary mixtures characterized by the following size and dispersive energy ratios: (1) ( σ22 / σ) 3 = 2 and ɛ22 / ɛ11 = 2; (2) ( σ22 / σ11 ) 3 = 1 and ɛ22 / ɛ11 = 2; and (3) ( σ22 / σ11 ) 3 = 1/2 and ɛ22 / ɛ11 = 2. In all cases, the unlike size parameter, σ12 , is kept constant and equal to the value given by the Lorentz combining rule ( σ12 = ( σ11 + σ22 )/2). However, different unlike dispersive energy parameter values are considered through the following combining rules: (a) ɛ12 = ( ɛ11 ɛ22 ) 1/2 (Berthelot rule); (b) ɛ12 = ɛ 11 (association); and (c) ɛ12 = ɛ 22 (solvation). The pressure and temperature dependence of the excess volume and excess enthalpy is studied using the NpT Monte Carlo simulation technique for all the systems considered. Additionally, the simplest conformal solution theory is used to check the adequacy of this approach in predicting the excess properties in a wide range of thermodynamic conditions and variety of binary mixtures. In particular, we have applied the van der Waals one-fluid theory to describe Lennard-Jones binary mixtures through the use of the JOHNSONet al. [1993, Molec. Phys. , 78 , 591] Helmholtz free energy. Agreement between simulation results and theoretical predictions is excellent in all cases and thermodynamic conditions considered. This work confirms the applicability of the van der Waals one-fluid theory in predicting excess thermodynamic properties of mixtures of spherical molecules. Furthermore, since binary mixtures of spherical Lennard-Jones molecules constitute the reference fluid to be used in perturbation theories for complex fluids, such as the statistical association fluid theory (SAFT), this work shows clearly the applicability of the conformal solution theory within the framework of SAFT for

  5. Explaining CMS lepton excesses with supersymmetry

    CERN Multimedia

    CERN. Geneva; Prof. Allanach, Benjamin

    2014-01-01

    1) Kostas Theofilatos will give an introduction to CMS result 2) Ben Allanach: Several CMS analyses involving di-leptons have recently reported small 2.4-2.8 sigma local excesses: nothing to get too excited about, but worth keeping an eye on nonetheless. In particular, a search in the $lljj p_T$(miss) channel, a search for $W_R$ in the $lljj$ channel and a di-leptoquark search in the $lljj$ channel and $ljj p_T$(miss) channel have all yielded small excesses. We interpret the first excess in the MSSM, showing that the interpretation is viable in terms of other constraints, despite only having squark masses of around 1 TeV. We can explain the last three excesses with a single R-parity violating coupling that predicts a non-zero contribution to the neutrinoless double beta decay rate.

  6. Genetics Home Reference: aromatase excess syndrome

    Science.gov (United States)

    ... Ogata T. Genomic basis of aromatase excess syndrome: recombination- and replication-mediated rearrangements leading to CYP19A1 overexpression. ... 2013 Oct 18. Citation on PubMed More from Genetics Home Reference Bulletins Rare Disease Day 2018 Darwin ...

  7. Prevention of modern teenager's computer excessive gambling

    OpenAIRE

    Shamsutdinova, D.

    2011-01-01

    This article is devoted to the prevention of young people's excessive gambling. The article organized and convincingly derived the prevention strategies dependent gaming behavior among young people and teenagers.

  8. Excessive deforestation of Gishwati Mountainous forest ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    sigp1. Excessive deforestation of Gishwati. Mountainous forest & biodiversity changes. Introduction. The Change in Forest cover in. Rwanda is result of the high growth of population density. The latter has doubled between 1978 and 2002. Over.

  9. Uterine rupture following incomplete molar pregnancy: a case report

    Directory of Open Access Journals (Sweden)

    Pourali L

    2013-03-01

    Full Text Available Background: In molar pregnancy, when hydatidiform changes are local and some embryonic components are observed, the term of partial mole is used. The risk of persistent trophoblastic tumor after partial mole is much lower than complete mole. In this persistent cases almost all are non metastatic. The aim of this study is to report a case of uterine rupture following incomplete molar pregnancy.Case presentation: The patient was a 26 year old woman with obstetric history of an abortion and one molar pregnancy and no child. She was referred to emergency unit in Ghaem University Hospital, Mashhad, Iran in May 2011. She had an evacuation curettage following molar pregnancy three months before and without any follow up visit. The patient was referred to emergency unit with hemorrhagic shock. She immediately underwent laparotomy. The uterine fundal rupture was repaired and evacuation curettage performed. In post operative evaluation, she had a nine millimeter metastatic nodule in base of right Lung. As a patient in low risk stage III, she received weekly intramuscular methotrexate (40mg/m2 for six courses. In follow up visit -hCG titer was negative (<10miu/ml at 5th week. Conclusion: In cases of in complete molar pregnancy risk of metastasis is very low. Serial beta-hCG titer is the most accurate method for detection of persistent gestational trophoblastic disease (GTN. In neglected cases like this case preservation of ruptured uterus in GTN is possible.

  10. Histopathologic Evaluation of Follicular Tissues Associated with Impacted Third Molars

    Directory of Open Access Journals (Sweden)

    M. Khorasani

    2008-06-01

    Full Text Available Objective: The aim of the present study was to histopathologically evaluate follicular tissues of third molars with pericoronal radiolucenciesof less than 2 millimeters.Materials and Methods: In this descriptive analytic study, 100 impacted third molars with normal follicular spaces were removed and their pericoronaltissues submitted for histopathologic examination. Different characteristicsof the epithelium and connective tissue were evaluated in all cases. Statisti-cal analysis was performed using chi square and Mann-Whitney tests.Results: In our study sample, 74% of the patients were female and 26% were male, ranging in age from 13 to 54 years (mean, 25.3 years. Lining epithelium was observed in 69% of the specimens of which 31%, 23% and 14% was cuboidal, squamous and columnar, respectively. A significant re-lationship was found between the presence of squamous epithelium and pa-tient age (P<0.05. Nonspecific chronic inflammation was the only patho-logic finding observed in 44% of the specimens. Inflammation was signifi-cantly associated with age and squamous metaplasia (P<0.05.Conclusion: Considering that pathologic lesions were not observed in anyof the studied cases, unerupted third molars should not be removed unless there is a clinical indication to do so, or in case the impacted molar shows evidence of pathological changes. Follow-up is suggested for asympto-matic impacted third molars.

  11. Prevalence of Taurodont Molars in a Selected Iranian Adult Population.

    Science.gov (United States)

    Jamshidi, Davoud; Tofangchiha, Maryam; Jafari Pozve, Nasim; Mohammadpour, Mahdis; Nouri, Bijan; Hosseinzadeh, Kazem

    2017-01-01

    Taurodontism is an anomaly characterized by elongated crowns and consumedly apical location of the bifurcation area. This study aimed to determine the prevalence of taurodontism in molars based on digital panoramic radiographies in eight cities of Iran. This descriptive cross-sectional study was conducted on 2360 digital panoramic radiographs taken for different treatment purposes. Demographic information of patients was recorded and radiographs were evaluated for presence of taurodont molars. The prevalence rates were calculated and the data were analyzed using SPSS software version 18 via paired t-test, chi square test and ANOVA. A total of 2360 panoramic radiographs (from 51.4% male and 48.6% female patients) were evaluated and the prevalence of taurodontism was reported 22.9% (22.6% in males and 23.3% in females) (P>0.05). Its prevalence was 51.67% in the right and 48.33% in the left quadrants (P>0.05), 34.1% in the mandible and 65.9% in the maxilla (P=0.000) and 79.52% in the second and 20.48% in the first molar (P=0.000). The prevalence of hypotaurodontism, mesotaurodontism and hypertaurodontism was 84.13%, 11.07% and 4.8%, respectively. The prevalence of taurodont molars was high in Iran and it was more common in the second molars and in the maxilla. Hypotaurodontism had the highest prevalence.

  12. Enthalpy and phase behavior of coal derived liquid mixtures: Technical progress report for the period October-December 1986

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.; Kidnay, A.J.

    1987-01-01

    The objectives of this program are to study the enthalpy and phase behavior of a selected ternary model compound system, representative of interactions present in coal derived liquids. Measurements have been made in a Freon 11 reference fluid-boil-off calorimeter, and an equilibrium flash vaporization apparatus. During the tenth quarter, enthalpy measurements for the m-cresol/quinoline/tetralin ternary system have been initiated and are included in Appendix A. Vapor liquid equilibria measurements for the m-cresol/quinoline/tetralin ternary system have been completed for four isotherms: 250, 275, 300, 325/sup 0/C, at various pressures. These results and a summary of progress to date for the VLE apparatus are in Appendix B. Also, predictions for the ternary system using the binary interaction parameters generated from previously obtained binary data were completed, and these results are also presented in Appendix B.

  13. Phospholipids as Biomarkers for Excessive Alcohol Use

    Science.gov (United States)

    2017-03-01

    of SM and LPC and the amount of alcohol consumption during the past month. The proposal has both scientific and practical significance in... alcohol use (EAU). Drinking becomes excessive when it causes or elevates the risk for alcohol -related problems or complicates the management of other...the quantity of alcohol consumption during the past month. 2. KEYWORDS: Excessive alcohol use, lipidomics, timeline follow back 3. ACCOMPLISHMENTS

  14. Romanian welfare state between excess and failure

    Directory of Open Access Journals (Sweden)

    Cristina Ciuraru-Andrica

    2012-12-01

    Full Text Available Timely or not, our issue can bring back to life some prolific discussions, sometimes diametrical. We strike the social assistance, where, at this moment, is still uncertain if, once unleashed the excess, the failure will come inevitably or there is a “Salvation Ark”. However, the difference between the excess and the failure of the welfare state is almost intangible, the reason of his potential failure being actually the abuses made until the start of depression.

  15. Organizational Inertia and Excessive Product Proliferation

    OpenAIRE

    Sakuraki, Rie

    2015-01-01

    This study investigates the internal factors of excessive product proliferation. Since empirical literature on product over-proliferation focused on how to optimize existing product portfolio, the causes of excessive product proliferation have so far attracted little attention. This study employs a case study of Shiseido, a famous Japanese cosmetics company, with particular attention to product proliferation in the Shiseido chain store channel, because external factors are mostly absent from ...

  16. Accuracy of the DLPNO-CCSD(T) method for non-covalent bond dissociation enthalpies from coinage metal cation complexes

    KAUST Repository

    Minenkov, Yury

    2015-08-27

    The performance of the domain based local pair-natural orbital coupled-cluster (DLPNO-CCSD(T)) method has been tested to reproduce the experimental gas phase ligand dissociation enthalpy in a series of Cu+, Ag+ and Au+ complexes. For 33 Cu+ - non-covalent ligand dissociation enthalpies all-electron calculations with the same method result in MUE below 2.2 kcal/mol, although a MSE of 1.4 kcal/mol indicates systematic underestimation of the experimental values. Inclusion of scalar relativistic effects for Cu either via effective core potential (ECP) or Douglass-Kroll-Hess Hamiltonian, reduces the MUE below 1.7 kcal/mol and the MSE to -1.0 kcal/mol. For 24 Ag+ - non-covalent ligand dissociation enthalpies the DLPNO-CCSD(T) method results in a mean unsigned error (MUE) below 2.1 kcal/mol and vanishing mean signed error (MSE). For 15 Au+ - non-covalent ligand dissociation enthalpies the DLPNO-CCSD(T) methods provides larger MUE and MSE, equal to 3.2 and 1.7 kcal/mol, which might be related to poor precision of the experimental measurements. Overall, for the combined dataset of 72 coinage metal ion complexes DLPNO-CCSD(T) results in a MUE below 2.2 kcal/mol and an almost vanishing MSE. As for a comparison with computationally cheaper density functional theory (DFT) methods, the routinely used M06 functional results in MUE and MSE equal to 3.6 and -1.7 kca/mol. Results converge already at CC-PVTZ quality basis set, making highly accurate DLPNO-CCSD(T) estimates to be affordable for routine calculations (single-point) on large transition metal complexes of > 100 atoms.

  17. Enthalpies of transfer of N-methylformamide, formamide, and N,N-dimethylformamide from methanol to methanol + dimethylsulfoxide mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Feakins, D.; O' Duinn, C.C.; Waghorne, W.E.

    1987-11-01

    The enthalpies of transfer of formamide, N-methylformamide and N,N-dimethylformamide from methanol to methanol + dimethylsulfoxide solvent systems have been measured. These data are analyzed in terms of a recently developed model of solvation in mixed solvents. The results of the data analyses indicate that preferential solvation of the different functional groups of the amides differs, the carbonyl oxygen being preferentially solvated by methanol and the nitrogen protons are by dimethylsulfoxide.

  18. Ab initio calculation of excess properties of La{sub 1−x}(Ln,An){sub x}PO{sub 4} solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany); Kowalski, Piotr M., E-mail: p.kowalski@fz-juelich.de [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany); Blanca-Romero, Ariadna [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany); Vinograd, Victor [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); Institute of Geoscience, Goethe Universität Frankfurt am Main, Altenhöferallee 1, 60438 Frankfurt (Germany); Bosbach, Dirk [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Jülich, Wilhelm-Johnen-Strasse, 52425 Jülich (Germany); JARA High-Performance Computing, Schinkelstrasse 2, 52062 Aachen (Germany)

    2014-12-15

    We used ab initio computational approach to predict the excess enthalpy of mixing and the corresponding regular/subregular model parameters for La{sub 1−x}Ln{sub x}PO{sub 4} (Ln=Ce,…, Tb) and La{sub 1−x}An{sub x}PO{sub 4} (An=Pu, Am and Cm) monazite-type solid solutions. We found that the regular model interaction parameter W computed for La{sub 1−x}Ln{sub x}PO{sub 4} solid solutions matches the few existing experimental data. Within the lanthanide series W increases quadratically with the volume mismatch between LaPO{sub 4} and LnPO{sub 4} endmembers (ΔV=V{sub LaPO{sub 4}}−V{sub LnPO{sub 4}}), so that W(kJ/mol)=0.618(ΔV(cm{sup 3}/mol)){sup 2}. We demonstrate that this relationship also fits the interaction parameters computed for La{sub 1−x}An{sub x}PO{sub 4} solid solutions. This shows that lanthanides can be used as surrogates for investigation of the thermodynamic mixing properties of actinide-bearing solid solutions. - Highlights: • The excess enthalpies of mixing for monazite-type solid solutions are computed. • The excess enthalpies increase with the endmembers volume mismatch. • The relationship derived for lanthanides is transferable to La{sub 1−x}An{sub x}PO{sub 4} systems.

  19. Rapid estimation of activation enthalpies for cytochrome-P450-mediated hydroxylations.

    Science.gov (United States)

    Mayeno, Arthur N; Robinson, Jonathan L; Reisfeld, Brad

    2011-03-01

    Cytochrome P450 (CYP) enzymes play a critical role in detoxication and bioactivation of xenobiotics; thus, the ability to predict the biotransformation rates and regioselectivity of CYP enzymes toward substrates is an important goal in toxicology and pharmacology. Here, we present the use of the semiempirical quantum chemistry method SAM1 to rapidly estimate relative activation enthalpies (ΔH(‡)) for the hydroxylation of aliphatic carbon centers of various substrates. The ΔH(‡) were determined via a reaction path calculation, in the reverse direction (RRP), using the iron-hydroxo-porphine intermediate and the substrate radical. The SAM1 ΔH(‡) were calculated via unrestricted Hartree-Fock (UHF) and configuration interaction (CI) formalisms for both the doublet and quartet spin states. The SAM1 RRP ΔH(‡), after subtracting a correction factor, were compared with density functional theory (DFT) B3LYP activation energies for two sets of substrates and showed R(2) ranging from 0.69 to 0.89, and mean absolute differences ranging from 1.2 ± 1.0 to 1.7 ± 1.5 kcal/mol. SAM1 UHF and CI RRP calculation times were, on average, more than 200 times faster than those for the corresponding forward reaction path DFT calculations. Certain key transition-state (TS) geometry measurements, such as the forming O···H bond length, showed good correlation with the DFT values. These results suggest that the SAM1 RRP approach can be used to rapidly estimate the DFT activation energy and some key TS geometry measurements and can potentially be applied to estimate substrate hydroxylation rates and regioselectivity by CYP enzymes. Copyright © 2010 Wiley Periodicals, Inc.

  20. Research of Workflow Efficiency in HighEnthalpy Air Flow Compact Generators

    Directory of Open Access Journals (Sweden)

    V. Yu. Aleksandrov

    2015-01-01

    Full Text Available To test the combustion chambers (CC of high-speed ramjet engine (ramjet it is necessary to create the inlet conditions as realistic as possible, including the stagnation temperature T0, the Mach number M0, and the total airflow pressure p0. To achieve T0 = 1000 ... 2000 K is possible using a high-enthalpy airflow generator (HAG providing the fired air-heating and oxygen balance compensation.Due to strict weight and size restrictions imposed by the test conditions of the ramjet CC and bench equipment, there is a need to reduce HAG size and weight. For small HAG the relevant tasks are to organize effective workflow and ensure combustion stability, which can be solved directly at the developmental testing stage.The characteristic criterion of the workflow efficiency in HAG is the completed physicochemical combustion processes of the working fluid components. This is due to the fact that in the testing process a possible after-burning component of the working fluid in the flow path of the ramjet CC has a significant impact on the studied characteristics of the engine, thereby having a detrimental effect on the quality of the experiment.The examination of the workflow efficiency in HAG showed that the use of hydrogen as a fuel allows us to achieve a high degree of completing the physicochemical processes and reaching the specified conditions at the CC inlet to the ramjet under test. The use of hydrocarbon fuels reduces the completion degree of the workflow process in HAG and is accompanied by the development of pressure pulsations.The data obtained can be used when developing various HAGs, including those intended for testing the CC of ramjets for the prospective aircrafts.

  1. Enthalpy measurement of coal-derived liquids. Technical progress report, February 1983-April 1983

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1983-05-31

    This quarter's work has concentrated on two primary areas. The first was the completion of experimental measurements of the associated factor. The second area was a look at current equation of state application. The work has progressed smoothly so far and should in future emphasize the computational work. The significant systems looked at this quarter were the C/sub 2/-C/sub 6/ alcohols, cresol, quinoline, and cresol-quinoline mixtures. The alcohols and cresols are important because the hydroxyl hydrogen bonding which is believed to be the primary association mechanism in coal liquids. Quinoline is significant because it is an excellent model for nitrogen containing constituents of coal liquids. The cresol-quinoline system, which was measured for range of system compositions, was studied because enthalpy data for a similar range of compositions was available. The results for most of these systems were reasonable and make important additions to previous data. The results for the quinoline-cresol mixture systems were curious and very different from anything previous to these measurements. The causes of these results are currently not well understood. Clearly they are due to complex interaction phenomena occurring in these systems. Since this behavior is not generally seen in complex mixtures, it is felt that the behavior is due to the fact that the cresol-quinoline system is a simple binary system which allows complex composition dependent solute-solute-solvent interactions to occur. This effect would also probably occur in ternary, quartenary, and maybe even higher systems. This behavior would tend to washout in coal liquids which have hundreds of components. As a result, it is felt that pure component systems are more valid models for coal liquid associations and that binary, etc., systems are too great a complexity to be currently understood.

  2. Der Weg ist Das Ziel: Enthalpy Relaxation Geospeedometry in Volcanic Facies

    Science.gov (United States)

    Dingwell, D. B.

    2006-12-01

    The advent of reliable high temperature scanning calorimetry has had a major impact on the analysis of the thermodynamics of geomaterials at high temperature. A relatively novel and unconventional use of scanning calorimetry - enthalpy relaxation geospeedometry - has been employed in volcanic facies in the past ten years. Using these techniques,information on the cooling of natural and synthetic glasses can be obtained. Reliable calibration of the technique on a wide range of glasses from various volcanic facies has led to the development of a fully quantitative method for the determination of effective cooling rate on pristine natural glasses. The evidence accumulated to date reveals an extraordinarily rich variation in volcanic cooling histories. The analysis of the glass transition region in volcanic glasses has yielded cooling rates over seven log units. The highest cooling rates are observed for explosively subaqueously erupted basalts from Loihi seamount. These filigran limu varieties are inferred to have cooled at up to >100,000 K/sec. The slowest effective cooling rates are observed in welded spatter-fed pantelleritic glasses from Mayor Island NZ for which values of several K/day have been inferred. Even whithin individual volcanic terrains, and individual eruptive events the span of thermal histories is impressive. At Teide, Tenerife, 4-5 orders of magnitude of variation have been recorded. Herein lies perhaps the real power of the technique - facies-specific thermal histories - whose employment in volcanology adds a useful tool to the understanding of pristine units. Finally, I observe that the calorimetric glass transition, once a nagging detail obstructing the interpretation of calorimetric results, has become a useful tool for understanding glass petrogenesis in nature.

  3. Enthalpy-Based Thermal Evolution of Loops: II. Improvements to the Model

    Science.gov (United States)

    Cargill, P. J.; Bradshaw, S. J.; Klimchuk, J. A.

    2011-01-01

    This paper further develops the zero-dimensional (0D) hydrodynamic coronal loop model "Enthalpy-based Thermal Evolution of Loops" (EBTEL) originally proposed by Klimchuk et al (2008), which studies the plasma response to evolving coronal heating. It has typically been applied to impulsive heating events. The basis of EBTEL is the modelling of mass exchange between the corona and transition region and chromosphere in response to heating variations, with the key parameter being the ratio of transition region to coronal radiation. We develop new models for this parameter that now include gravitational stratification and a physically motivated approach to radiative cooling. A number of examples are presented, including nanoflares in short and long loops, and a small flare. It is found that while the evolution of the loop temperature is rather insensitive to the details of the model, accurate tracking of the density requires the inclusion of our new features. In particular, we are able to now obtain highly over-dense loops in the late cooling phase and decreases to the coronal density arising due to stratification. The 0D results are compared to a 1D hydro code (Hydrad). The agreement is acceptable, with the exception of the flare case where some versions of Hydrad can give significantly lower densities. This is attributed to the method used to model the chromosphere in a flare. EBTEL is suitable for general use as a tool for (a) quick-look results of loop evolution in response to a given heating function and (b) situations where the modelling of hundreds or thousands of elemental loops is needed. A single run takes a few seconds on a contemporary laptop.

  4. Enthalpy measurement of coal-derived liquids. Quarterly technical progress report, July--September 1978. [148 to 459/sup 0/F and 100 to 300 psia

    Energy Technology Data Exchange (ETDEWEB)

    Kidnay, A.J.; Yesavage, V.F.

    1978-12-01

    Experimental measurements were completed on a naphtha sample (1046) furnished by the Pittsburgh and Midway Coal Mining Company. A total of 38 measurements were made in the temperature region 148 to 459/sup 0/F, and at pressures of 100 and 300 psia. Additional analytical work was completed on the SRC-I naphtha whose enthalpy measurements were reported previously. Comparisons are given between the experimental SRC-I naphtha enthalpies and the available enthalpy data on petroleum fractions, including Kesler and Lee's correlation of these data. (LTN)

  5. Comparison and verification of enthalpy schemes for polythermal glaciers and ice sheets with a one-dimensional model

    CERN Document Server

    Blatter, Heinz

    2014-01-01

    The enthalpy method for the thermodynamics of polythermal glaciers and ice sheets is tested and verified by a one-dimensional problem (parallel-sided slab). The enthalpy method alone does not include explicitly the Stefan-type energy- and mass-flux matching conditions at the cold-temperate transition surface (CTS) that separates the upper cold from the lower temperate layer. However, these transition conditions are important for correctly determining the position of the CTS. For the numerical solution of the polythermal slab problem, we consider a two-layer front-tracking scheme as well as three different one-layer schemes that feature a single grid for both layers. Computed steady-state temperature and moisture profiles are verified with exact solutions, and transient solutions computed by the one-layer schemes are compared with those of the two-layer scheme, considered to be a reliable reference. While the conventional one-layer enthalpy scheme (that does not include the transition conditions at the CTS) ca...

  6. External root resorption of the second molar associated with third molar impaction: comparison of panoramic radiography and cone beam computed tomography.

    Science.gov (United States)

    Oenning, Anne Caroline Costa; Neves, Frederico Sampaio; Alencar, Phillipe Nogueira Barbosa; Prado, Rodrigo Freire; Groppo, Francisco Carlos; Haiter-Neto, Francisco

    2014-08-01

    The aim of the present study was to compare panoramic radiography and cone beam computed tomography (CBCT) for the assessment of external root resorption (ERR) of second molars associated with impacted third molars. In addition, the prevalence of ERR in second molars and the inclinations of the third molars more associated with ERR were investigated in both imaging methods. The sample consisted of 66 individuals with maxillary and mandibular impacted third molars (n = 188) seen on panoramic radiographs and CBCT images. The presence of ERR on the adjacent second molar was investigated, and the position of the third molar was determined using Winter's classification (vertical, horizontal, mesioangular, distoangular, and transverse). Statistical analysis was performed using the χ(2) test, Fisher exact test, and 2-proportion Z test (the significance level was set at 5%). A significantly greater number of cases of ERR (P third molars in mesioangular and horizontal inclinations were more likely to cause resorption of the adjacent teeth. CBCT should be indicated for the diagnosis of ERR in second molars when direct contact between the mandibular second and third molars has been observed on panoramic radiographs, especially in mesioangular or horizontal impactions. Furthermore, considering the propensity of these teeth to cause ERR in second molars, third molar prophylactic extraction could be suggested. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  7. La hiperdontia en región de molares Hyperdontia in molar region

    Directory of Open Access Journals (Sweden)

    George Táccio de Miranda Candeiro

    2011-12-01

    Full Text Available La hiperdontia constituye una de las anomalías más estudiadas de la dentición humana. Esa alteración representa la aparición de uno o más dientes en cantidades mayores de lo normal, que puede ocurrir en la mandíbula o maxila y de manera unilateral o bilateral. La etiología de los dientes supernumerarios puede ser explicada principalmente por hiperactividad de la lámina dentaria en la fase inicial. Es importante la detección precoz de dientes supernumerarios porque se ha visto una serie de complicaciones como los diastemas, que pueden causar en la cavidad bucal: retardo de la erupción o dientes impactados, posicionamiento inadecuado de dientes permanentes, desajuste oclusal y el desarrollo de quistes y tumores odontógenos. Así el diagnóstico es normalmente realizado a partir de un examen radiográfico convencional, principalmente la radiografía panorámica. Este trabajo tuvo como objetivo relatar 4 casos clínicos de pacientes con presencia de molares supernumerarios, que fueron atendidos en el Servicio de Radiología de la Escuela de Odontología de la Universidad Federal de Ceará.Hyperdontia is one of the more studied anomalies of human dentition. This alteration represents the appearance of one or more teeth in a number greater of normal, occurring in mandible or in maxilla and could be unilateral or bilateral. The etiology of supernumerary teeth may be explained mainly due to the hyperactivity of dental plate in its initial phase; its early detection is important because of there have been a series of complications that may to cause diastemata, eruption retard or impacted teeth, inappropriate positioning of permanent teeth, occlusal misalignment and the development of odontogenic cysts or tumors. Thus, the diagnosis is normally made from a conventional radiographic examination, mainly the panoramic X-ray. The objective of present paper is the present four clinical cases of patients presenting with supernumerary molars, seen in

  8. Variation in buccal surface morphology of deciduous first molars

    Directory of Open Access Journals (Sweden)

    M Simratvir

    2012-01-01

    Full Text Available Background: The buccal bulge of the deciduous first molars has always been a restorative challenge to the pediatric dentist. Morphologically it may vary from a slight prominence to a well-developed cusp-like structure. Aim: This study was conducted to determine the variable buccal surface morphology of deciduous first molar and its clinical relevance. Materials and Methods: A prospective study was conducted whereby 2016 patients visiting the outpatient clinic of dental hospital over 1 year were evaluated. Any variation in buccal surface morphology of the deciduous first molars was recorded photographically or by replicating in dental stone. Results: Varied morphological patterns on buccal surface were observed for which a new classification scheme has been proposed. Conclusion: The surface morphology of deciduous teeth crowns must be studied carefully as it may be indicative of pulpal extensions and accessory roots, requiring consideration during restorative treatment planning.

  9. Pendulum Therapy of Molar Distalization in Mixed Dentition.

    Science.gov (United States)

    Patil, Raju Umaji; Prakash, Amit; Agarwal, Anshu

    2016-01-01

    Early and timely pedo-orthodontic treatment is aimed at eliminating the disturbances of skeletal or dentoalveolar development, to harmonize the stomatognathic system before the full eruption of all permanent teeth. The advantages of pendulum appliance are its minimal dependence on patient's compliance (child cooperation), ease of fabrication, onetime activation and adjustment of the springs if necessary to correct minor transverse and vertical molar positions. This article reports a successful treatment method of class II malocclusion with pendulum appliance in mixed dentition phase. Distalization of maxillary molar was done, followed by guidance of canine impaction orthodontically and other dental correction using 0.022 MBT appliances. Posttreatment results were stable and remarkable. How to cite this article: Patil RU, Prakash A, Agarwal A. Pendulum Therapy of Molar Distalization in Mixed Dentition. Int J Clin Pediatr Dent 2016;9(1):67-73.

  10. Anxiety and extraction of third molars in Turkish patients.

    Science.gov (United States)

    Garip, Hasan; Abali, Osman; Göker, Kamil; Göktürk, Ulkü; Garip, Yildiz

    2004-12-01

    Preoperative anxiety is widespread and adversely affects a patient's physical and psychological outcome. Extraction of third molars is common, and many patients complain of anxiety and emotional disturbance. We assessed the anxiety of patients in Turkey before extraction of third molars. A total of 120 patients were admitted for removal of one or more third molars under local anaesthesia. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) and Spielberger's State Trait Anxiety Inventory (STAI) were used to evaluate anxiety. The results showed that women were significantly more anxious than men; women who had not had a previous operation were more anxious than other women; there was no difference in the anxiety scores of patients who had previously had a local anaesthetic and those who had not; there were no differences in anxiety as measured by trait scores; patients who wanted a lot of information were more anxious.

  11. Microbiology of the pericoronal pouch in mandibular third molar pericoronitis.

    Science.gov (United States)

    Leung, W K; Theilade, E; Comfort, M B; Lim, P L

    1993-10-01

    The microorganisms associated with mandibular third molar pericoronitis were investigated using direct microscopy and anaerobic culture method. The pericoronal pouch was sampled with paper points in A) 8 patients without mandibular third molar pericoronitis and B) 6 patients with mandibular third molar pericoronitis. Under the microscope, the microflora was found to be a complex mixture comprising gram-positive and gram-negative cocci, rods and filaments (including fusiform and curved rods), motile rods and spirochetes. Significantly higher proportions of motile, gram-negative rods were found in group B than in group A. The predominant cultivable microflora of 9 samples: A (4) and B (5) comprised several species of facultative and obligate anaerobic bacteria, namely Peptostreptococcus, Streptococcus, Actinomyces, Eubacterium, Propionibacterium, Veillonella, Porphyromonas, Prevotella, Bacteriodes, Fusobacterium, Campylobacter, Staphylococcus, Stomatococcus, Lactobacillus, Neisseria, Capnocytophaga, Haemophilus, Selenomonas and Centipeda species. The microflora in pericoronitis appeared similar to that of diseased periodontal pockets.

  12. COMPLICATIONS AFTER EXTRACTION OF IMPACTED THIRD MOLARS - LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    Elitsa G. Deliverska

    2016-07-01

    Full Text Available Third molar surgery is the most common procedure performed by oral and maxillofacial surgeons worldwide. This article addresses the incidence of specific complications and, where possible, offers a preventive or management strategy. Complications, such as pain, dry socket, swelling, paresthesia of the lingual or inferior alveolar nerve, bleeding, and infection are most common. Factors thought to influence the incidence of complications after third molar removal include age, gender, medical history, oral contraceptives, presence of pericoronitis, poor oral hygiene, smoking, type of impaction, relationship of third molar to the inferior alveolar nerve, surgical time, surgical technique, surgeon experience, use of perioperative antibiotics, use of topical antiseptics, use of intra-socket medications, and anaesthetic technique. For the general dental practitioner, as well as the oral and maxillofacial surgeon, it is important to be familiar with all the possible complications after this procedure. This improves patient education and leads to prevention, early recognition and management.

  13. Solution viscosity – molar mass relationships for poly(butylene succinate and discussion on molar mass analysis

    Directory of Open Access Journals (Sweden)

    Q. Charlier

    2015-05-01

    Full Text Available Poly(butylene succinate (PBS is currently developing due to its biodegradability and the similarity of its mechanical properties to those of polyolefins. Relationships between the number average molar mass, Mn, and solution viscosity such as [η] and ηred were derived for this aliphatic polyester. Mn values were determined by end-group analysis and size exclusion chromatography (SEC. Mark-Houwink-Sakurada (MHS parameters were proposed in two solvents and for the different molar masses and viscosity measurement methods. As an example, the MHS equations were respectively, [η] =6.4•10–4•Mn0.67 in chloroform and [η] = 7.1•10–4•Mn0.69 in 50/50 wt% 1,2-dichlorobenzene/phenol at 25°C for molar masses measured by SEC in hexafluoro isopropanol (HFIP with poly(methyl methacrylate (PMMA standards. Empirical relationships were also suggested to derive Mn directly from reduced viscosity, ηred, which is much easier to determine than intrinsic viscosity. With these data, the number average molar mass of PBS can be conveniently estimated from a single viscosity measurement. In addition, it was shown that PBS contains 1–2 wt% of cyclic oligomers produced during esterification and that molar masses determined by taking this fraction into account or not were significantly different, especially for long chains.

  14. Piezoelectric Versus Conventional Rotary Techniques for Impacted Third Molar Extraction

    Science.gov (United States)

    Jiang, Qian; Qiu, Yating; Yang, Chi; Yang, Jingyun; Chen, Minjie; Zhang, Zhiyuan

    2015-01-01

    Abstract Impacted third molars are frequently encountered in clinical work. Surgical removal of impacted third molars is often required to prevent clinical symptoms. Traditional rotary cutting instruments are potentially injurious, and piezosurgery, as a new osteotomy technique, has been introduced in oral and maxillofacial surgery. No consistent conclusion has been reached regarding whether this new technique is associated with fewer or less severe postoperative sequelae after third molar extraction. The aim of this study was to compare piezosurgery with rotary osteotomy techniques, with regard to surgery time and the severity of postoperative sequelae, including pain, swelling, and trismus. We conducted a systematic literature search in the Cochrane Library, PubMed, Embase, and Google Scholar. The eligibility criteria of this study included the following: the patients were clearly diagnosed as having impacted mandibular third molars; the patients underwent piezosurgery osteotomy, and in the control group rotary osteotomy techniques, for removing impacted third molars; the outcomes of interest include surgery time, trismus, swelling or pain; the studies are randomized controlled trials. We used random-effects models to calculate the difference in the outcomes, and the corresponding 95% confidence interval. We calculated the weighted mean difference if the trials used the same measurement, and a standardized mean difference if otherwise. A total of seven studies met the eligibility criteria and were included in our analysis. Compared with rotary osteotomy, patients undergoing piezosurgery experienced longer surgery time (mean difference 4.13 minutes, 95% confidence interval 2.75–5.52, P trismus in the piezosurgery groups. The number of included randomized controlled trials and the sample size of each trial were relatively small, double blinding was not possible, and cost analysis was unavailable due to a lack of data. Our meta-analysis indicates that although

  15. Partial Molar Volumes of Aqua Ions from First Principles.

    Science.gov (United States)

    Wiktor, Julia; Bruneval, Fabien; Pasquarello, Alfredo

    2017-08-08

    Partial molar volumes of ions in water solution are calculated through pressures obtained from ab initio molecular dynamics simulations. The correct definition of pressure in charged systems subject to periodic boundary conditions requires access to the variation of the electrostatic potential upon a change of volume. We develop a scheme for calculating such a variation in liquid systems by setting up an interface between regions of different density. This also allows us to determine the absolute deformation potentials for the band edges of liquid water. With the properly defined pressures, we obtain partial molar volumes of a series of aqua ions in very good agreement with experimental values.

  16. Treatment of Ectopic Mandibular Second Permanent Molar with Elastic Separators

    Directory of Open Access Journals (Sweden)

    R. Rajesh

    2014-01-01

    Full Text Available Ectopic eruption is a developmental disturbance in which the tooth fails to follow its normal eruption pathway. Ectopic eruption of the second molar is relatively rare. This paper presents the case of thirteen-year-old male with an ectopic mandibular second permanent molar. The condition was corrected with surgical exposure and placement of elastic separators. This case report lays emphasis on the practice of basic methods to obtain acceptable results rather than extensive surgical or orthodontic corrections. It is advised that ectopic teeth should not be neglected especially when it concerns developing caries and malocclusion.

  17. Partial molar quantity of an intensive mother function

    Science.gov (United States)

    Koga, Yoshikata

    2012-09-01

    A new formal definition is given to the partial molar quantity of a component i for an intensive mother function. We perturb the entire system by increasing the amount of the target component by δni keeping others constant and measure the response of the system in terms of an intensive mother function, Φ, δΦ. We then define its partial molar quantity of the ith component, ϕi, as ϕi = [δΦ/{δni/(N + δni)

  18. First molar health status in different craniofacial relationships

    Directory of Open Access Journals (Sweden)

    Linjawi AI

    2016-07-01

    Full Text Available Amal I Linjawi Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia Objective: To investigate the association between the health status of permanent first molars and different craniofacial relationships among adolescents. Study design: This is a retrospective study on patients’ records aged 11–15 years. Sex, skeletal relationship, vertical growth pattern, malocclusion, overjet, and overbite were assessed. The health status of permanent first molars was recorded from the orthopantomograms and intraoral photographs as “sound” and “not sound”. Chi-square, Mann–Whitney U and Kruskal–Wallis tests, and Pearson’s correlation coefficient were used to analyze and correlate the assessed variables. Significance level was set at P<0.05. Results: A total of 210 records were evaluated; 81 were male, 68 had Class I and 91 had Class II skeletal relationships. More than half of the subjects had normal (n=67 to moderate deep bite (n=72; normal (n=91, moderately increased (n=54, to severely increased (n=50 overjet; and Class I (n=106 and Class II division 1 (n=75 malocclusion. Significant differences were found in the health status of the permanent first molars with respect to sex (P=0.034, vertical growth pattern (P=0.01, and overbite (P=0.047. Strong correlations were only found between the health status of the permanent first molars and the following variables: sex (P=0.036 and vertical growth pattern (P=0.004. Significant correlation was further found between the upper left first molar health status and sex (P=0.019 and the lower right first molar health status and the vertical growth pattern (P=0.001. No significant association was found with the anteroposterior craniofacial relationships (P>0.05. Conclusion: Sex difference and vertical growth patterns were found to be potential predictors of the health status of the permanent first molars. No significant association was found with the

  19. Special Contribution: Third Molar Clinical Trials Annotated Bibliography.

    Science.gov (United States)

    White, Raymond P; Fisher, Elda L; Magraw, Caitlin B L; Phero, James; Abdelbaky, Omar; Sherwood, Colin; Nelson, Blake

    2016-01-01

    To provide clinicians with an annotated bibliography of published articles from research funded externally by the Oral and Maxillofacial Surgery Foundation, spanning 1996 to 2015, addressing the topic of third molar management. A brief summary for each article was generated by the respective authors. The complete annotated bibliography generated by the authors is included in the Appendix. The annotated bibliography provides clinicians and other interested individuals with a summary of current literature emanating from clinical studies on third molar topics. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Patient's perception on mini-screws used for molar distalization

    OpenAIRE

    Blaya, Micéli Guimarães; Blaya, Diego Segatto; Guimarães, Magáli Beck; Hirakata, Luciana M.; Marquezan, Marcela

    2010-01-01

    PURPOSE: The objective of this study was to evaluate and compare the perceived pain intensity, side effects and discomfort related to the moment of placement, during mechanics and removal of a mini-screw for molar distalization in orthodontic treatment. METHODS: The sample consisted of 30 adult patients with a mean age of 30 years old, with class II malocclusion subdivision right or left. A mini-screw was installed in each patient, in the maxillary arch to provide a molar distalization. The p...

  1. [What nosographic framework for excessive tanning?].

    Science.gov (United States)

    Petit, A; Karila, L; Lejoyeux, M

    2014-04-01

    Socially valorised tanning, like other forms of behaviour, can take on an addictive aspect. Excessive tanning, defined by the presence of impulsivity and repetition of tanning that leads to personal distress, is a psychiatric disorder that has only recently been recognized. This finding is based on the observations of many dermatologists who report an addictive relationship in their patients with tanning cabins despite announcement of the diagnosis of malignant melanoma. This article attempts to synthesize the existing literature on excessive tanning and addiction to investigate possible associations. This review focuses on the prevalence, clinical features, aetiology, and treatment of this disorder. The literature review was conducted from 1983 to 2012, using PubMed, Google Scholar, EMBASE, and PsycInfo, using the following keywords alone or combined: Tanning, Addiction, Sunbeds, Skin cancer prevention, and Treatment. We investigated different models to determine how excessive tanning met these criteria. Excessive Tanning was described in the 2000s by an American dermatologist, Carolyn Heckman. Wartham et al. were the first to have proposed a theoretical framework for addiction to sunbathing, as well as two scales (m CAGE and m DSM IV) for the diagnosis and to assess the degree of addiction. These diagnostic criteria describe the craving like-symptoms, the feeling of losing control, or the continuation of the behavior despite knowledge of negative consequences. Excessive Tanning is not present in the classifications of the DSM or ICD, but may be related to Addiction, Obsessive-Compulsive Disorder, Impulse control disorders, Anorexia, or Body Dysmorphic Disorder. Excessive tanning can be included in the spectrum of behavioural addictions due its clinical characteristics in common with classics addictive disorders. They are a variety of other models, which may offer an explanation for or insight into tanning behaviour. Further studies must be controlled, notably on

  2. Impact of Flight Enthalpy, Fuel Simulant, and Chemical Reactions on the Mixing Characteristics of Several Injectors at Hypervelocity Flow Conditions

    Science.gov (United States)

    Drozda, Tomasz G.; Baurle, Robert A.; Drummond, J. Philip

    2016-01-01

    The high total temperatures or total enthalpies required to duplicate the high-speed flight conditions in ground experiments often place stringent requirements on the material selection and cooling needs for the test articles and intrusive flow diagnostic equipment. Furthermore, for internal flows, these conditions often complicate the use of nonintrusive diagnostics that need optical access to the test section and interior portions of the flowpath. Because of the technical challenges and increased costs associated with experimentation at high values of total enthalpy, an attempt is often made to reduce it. This is the case for the Enhanced Injection and Mixing Project (EIMP) currently underway in the Arc-Heated Scramjet Test Facility at the NASA Langley Research Center. The EIMP aims to investigate supersonic combustion ramjet (scramjet) fuel injection and mixing physics, improve the understanding of underlying physical processes, and develop enhancement strategies and functional relationships between mixing performance and losses relevant to flight Mach numbers greater than 8. The experiments will consider a "direct-connect" approach and utilize a Mach 6 nozzle to simulate the combustor entrance flow of a scramjet engine. However, while the value of the Mach number is matched to that expected at the combustor entrance in flight, the maximum value of the total enthalpy for these experiments is limited by the thermal-structural limits of the uncooled experimental hardware. Furthermore, the fuel simulant is helium, not hydrogen. The use of "cold" flows and non-reacting mixtures of fuel simulants for mixing experiments is not new and has been extensively utilized as a screening technique for scramjet fuel injectors. In this study, Reynolds-averaged simulations are utilized (RAS) to systematically verify the implicit assumptions used by the EIMP. This is accomplished by first performing RAS of mixing for two injector configurations at planned nominal experimental

  3. Antidepressant induced excessive yawning and indifference

    Directory of Open Access Journals (Sweden)

    Bruno Palazzo Nazar

    2015-03-01

    Full Text Available Introduction Antidepressant induced excessive yawning has been described as a possible side effect of pharmacotherapy. A syndrome of indifference has also been described as another possible side effect. The frequency of those phenomena and their physiopathology are unknown. They are both considered benign and reversible after antidepressant discontinuation but severe cases with complications as temporomandibular lesions, have been described. Methods We report two unprecedented cases in which excessive yawning and indifference occurred simultaneously as side effects of antidepressant therapy, discussing possible physiopathological mechanisms for this co-occurrence. Case 1: A male patient presented excessive yawning (approximately 80/day and apathy after venlafaxine XR treatment. Symptoms reduced after a switch to escitalopram, with a reduction to 50 yawns/day. Case 2: A female patient presented excessive yawning (approximately 25/day and inability to react to environmental stressors with desvenlafaxine. Conclusion Induction of indifference and excessive yawning may be modulated by serotonergic and noradrenergic mechanisms. One proposal to unify these side effects would be enhancement of serotonin in midbrain, especially paraventricular and raphe nucleus.

  4. The effect of a fourth element (Co, Cu, Fe, Pd) on the standard enthalpy of formation of the Heusler compound Ni{sub 2}MnSn

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Ming, E-mail: myin1@hawk.iit.edu; Nash, Philip

    2016-05-15

    The standard enthalpies of formation of quaternary Heusler compounds (X, Ni){sub 2}MnSn (X = Co, Cu, Fe, Pd) were investigated experimentally using high temperature direct reaction calorimetry. Lattice parameters of these compounds were determined using X-ray diffraction analysis. Microstructures were identified using scanning electron microscopy and energy dispersive spectroscopy. The effect of an additional X element on the standard enthalpy of formation of the Heusler compound Ni{sub 2}MnSn is discussed. - Highlights: • Enthalpies of formation of (X,Ni){sub 2}YZ (X = Co, Cu, Fe, Pd) were measured by drop calorimeters. • Magnetic contribution to enthalpy of formation plays an important role. • Introducing a fourth element could stabilize an unstable Heusler structure. • Lattice parameters do not necessarily obey the Vegard's law. • It is possible to tailor properties of Heusler compounds with enough background information.

  5. Cicatrización periodontal del segundo molar mandibular tras la exodoncia del tercer molar mandibular incluido

    OpenAIRE

    Inocêncio Teixeira de Faria, Ana Cristina

    2015-01-01

    La extracción quirúrgica del tercer molar (M3) puede provocar complicaciones periodontales en la cara distal del segundo molar (M2) adyacente. Se realizó un estudio clínico prospectivo a 12 meses en 25 pacientes jóvenes sanos (edad media 21 años) sometidos a 40 extracciones quirúrgicas de M3 mandibulares incluidos con elevado riesgo periodontal, con objeto de estudiar la cicatrización periodontal espontánea en la cara distal del M2. Prequirúrgicamente y a 3, 6 y 12 meses tras l...

  6. Self-diffusion in crystalline silicon: A single diffusion activation enthalpy down to 755°

    Science.gov (United States)

    Südkamp, Tobias; Bracht, Hartmut

    2016-09-01

    Self-diffusion in silicon and the contribution of vacancies and self-interstitials have been controversially discussed for 50 yr. Most recent results show that the intrinsic silicon self-diffusion coefficient deviates from an Arrhenius-type, single exponential function for temperatures below 950° [Y. Shimizu, M. Uematsu, and K. M. Itoh, Phys. Rev. Lett. 98, 095901 (2007), 10.1103/PhysRevLett.98.095901; R. Kube, H. Bracht, E. Hüger, H. Schmidt, J. L. Hansen, A. N. Larsen, J. W. Ager, E. E. Haller, T. Geue, and J. Stahn, Phys. Rev. B 88, 085206 (2013), 10.1103/PhysRevB.88.085206]. This led us to propose temperature-dependent thermodynamic properties of vacancies in order to achieve full consistency to vacancy-mediated dopant diffusion in silicon. Concepts of temperature-dependent properties of native defects or distinct forms of defects with different formation entropies suggested by Cowern et al. [N. E. B. Cowern, S. Simdyankin, C. Ahn, N. S. Bennett, J. P. Goss, J.-M. Hartmann, A. Pakfar, S. Hamm, J. Valentin, E. Napolitani, D. De Salvador, E. Bruno, and S. Mirabella, Phys. Rev. Lett. 110, 155501 (2013), 10.1103/PhysRevLett.110.155501] question the present understanding on atomic transport in semiconductors. To verify these concepts, additional self-diffusion experiments under particular gettering conditions were performed. As a result, silicon self-diffusion was found to be accurately described by one single diffusion activation enthalpy of (4.73 ±0.02 ) eV down to 755°C. This provides full consistency to dopant diffusion without claiming native-defect concepts that were originally proposed by Seeger and Chik in 1968 [A. Seeger and K. P. Chik, Phys. Stat. Sol. 29, 455 (1968), 10.1002/pssb.19680290202] and confirms most recent density functional theory calculations on the activation energy of self-diffusion via vacancies and self-interstitials. Overall, this unravels the old debate of self-diffusion in silicon with the supposed intrinsic temperature dependence.

  7. Effect of halogen substitution on the enthalpies of solvation and hydrogen bonding of organic solutes in chlorobenzene and 1,2-dichlorobenzene derived using multi-parameter correlations

    Energy Technology Data Exchange (ETDEWEB)

    Varfolomeev, Mikhail A.; Rakipov, Ilnaz T.; Khachatrian, Artashes A. [Department of Physical Chemistry, Kazan Federal University, Kremlevskaya 18, Kazan 420008 (Russian Federation); Acree, William E., E-mail: acree@unt.edu [Department of Chemistry, 1155 Union Circle # 305070, University of North Texas, Denton, TX 76203-5017 (United States); Brumfield, Michela [Department of Chemistry, 1155 Union Circle # 305070, University of North Texas, Denton, TX 76203-5017 (United States); Abraham, Michael H. [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

    2015-10-10

    Graphical abstract: - Highlights: • Enthalpies of solution measured for 43 solutes dissolved in chlorobenzene. • Enthalpies of solution measured for 72 solutes dissolved in 1,2-dichlorobenzene. • Mathematical expressions derived for predicting enthalpies of solvation of solutes in chlorobenzene. • Mathematical expressions derived for predicting enthalpies of solvation of solutes in 1,2-chlorobenzene. - Abstract: Enthalpies of solution at infinite dilution at 298 K, Δ{sub soln}H{sup A/Solvent}, have been measured by isothermal solution calorimetry for 43 and 72 organic solutes dissolved in chlorobenzene and 1,2-dichlorobenzene, respectively. The measured Δ{sub soln}H{sup A/Solvent} data, along with published Δ{sub soln}H{sup A/Solvent} values taken from the published literature for solutes dissolved in both chlorobenzene solvents, were converted to enthalpies of solvation, Δ{sub solv}H{sup A/Solvent}, using standard thermodynamic equations. Abraham model correlations were developed from the experimental Δ{sub solv}H{sup A/Solvent} data. The best derived correlations describe the experimental gas-to-chlorobenzene and gas-to-1,2-dichlorobenzene enthalpies of solvation to within standard deviations of 1.5 kJ mol{sup −1} and 1.9 kJ mol{sup −1}, respectively. Enthalpies of X−H…π (X – O, N, and C) hydrogen bond formation of proton donor solutes (alcohols, amines, chlorinated hydrocarbons, etc.) with chlorobenzene and 1,2-dichlorobenzene were calculated based on the Abraham solvation equation. Obtained values are in good agreement with the results determined using conventional methods.

  8. Low enthalpy geothermal energy: borehole heat exchangers (BHE). Geological and geothermal supervision during active construction in support of the energy certification of buildings - ESBE certification plan

    OpenAIRE

    Lorenzo Cadrobbi; Fioroni Daniele; Alessandro Bozzoli

    2012-01-01

    This article draws on the experience matured while working with low-enthalpy geothermic installations both in the design and executive phase as well as ongoing monitoring, within the scope of energy conservation as it relates to building and construction. The goal is to illustrate the feasibility of adopting the ESBE certification protocol (Certification of Energy Efficient Low-Enthalpy Probes) aimed at optimizing the harnessing of local geothermic resources to satisfy the energy requirements...

  9. Limiting law excess sum rule for polyelectrolytes.

    Science.gov (United States)

    Landy, Jonathan; Lee, YongJin; Jho, YongSeok

    2013-11-01

    We revisit the mean-field limiting law screening excess sum rule that holds for rodlike polyelectrolytes. We present an efficient derivation of this law that clarifies its region of applicability: The law holds in the limit of small polymer radius, measured relative to the Debye screening length. From the limiting law, we determine the individual ion excess values for single-salt electrolytes. We also consider the mean-field excess sum away from the limiting region, and we relate this quantity to the osmotic pressure of a dilute polyelectrolyte solution. Finally, we consider numerical simulations of many-body polymer-electrolyte solutions. We conclude that the limiting law often accurately describes the screening of physical charged polymers of interest, such as extended DNA.

  10. Molar Intubation for Intra Oral Swellings:Our Experience

    Directory of Open Access Journals (Sweden)

    Meenoti Potdar

    2008-01-01

    Full Text Available Molar intubation is a technique of laryngoscopy that can be used for anticipated difficult intubation in cases where standard laryngoscopy technique is difficult due to presence of any intraoral mass that anatomically hampers laryngoscopy or that bleeds on touch. This technique is very easy, reliable and rewarding but should be practiced on normal patients for easy application in actual difficult cases.

  11. Variant Root Morphology of Third Mandibular Molar in Normal and ...

    African Journals Online (AJOL)

    isaac kipyator

    2017-11-12

    Nov 12, 2017 ... Anatomy Journal of Africa. 2017. Vol 6 (3): 1052 - 1061. 1052. ORIGINAL COMMUNICATION. Variant Root Morphology of Third Mandibular Molar in Normal and. Impacted Teeth. Isaac Kipyator Bokindo1, Fawzia Butt 2,3, Francis Macigo4. 1School of Dental Sciences, University of Nairobi, Nairobi, Kenya.

  12. Ectopic (tubal) Molar Gestation: Report Of Two Cases | Abdul ...

    African Journals Online (AJOL)

    Ectopicmolar gestation is a rare event. Itsmalignant potential is similar to that of an intrauterine molar pregnancy. To document two cases of tubalmolar gestations seen over a 10-year period. Case series. Two young Nigerian undergraduates presented with features of ruptured tubal pregnancy. They had total salpingectomy ...

  13. Management of inflammatory complications in third molar surgery: A ...

    African Journals Online (AJOL)

    Results: Methods ranges from surgical closure techniques, use of drains, physical therapy and pharmacological means. Studies reviewed have shown that no single modality effectively minimizes postoperative pain, swelling and trismus without undesirable effects. Conclusion: Inflammatory complications after third molar ...

  14. SIGNS Molar tooth sign − looking beyond the obvious

    African Journals Online (AJOL)

    The molar tooth sign refers to the characteristic appearance on axial CT or MRI of enlarged and horizontally directed columnar structures on each side of the midline flanking a deep interpeduncular fossa.[1] This appearance is a result of absence or hypoplasia of the cerebellar vermis, lack of normal dorsal decussation and ...

  15. Measurement of the specific and the apparent molar volumes of ...

    African Journals Online (AJOL)

    The objective was to understand the extent to which the acids can disturb the structure of the solvent as well as affect the micellar characteristics. The specific volumes were obtained by fitting the measured viscosity data to the Einstein equation while the apparent molar volumes were obtained using the pycnometric method.

  16. Complete molar pregnancy in a 53-year-old woman

    African Journals Online (AJOL)

    Enrique

    43. SA JOURNAL OF RADIOLOGY • May 2004. CASE REPORT. Introduction. This case emphasises the role of sonography in the diagnosis of a com- plete molar pregnancy. Case report. A 53-year-old female, para 13 gravid 13, presented to the casualty department of Pretoria Academic. Hospital with a complaint of PV (per.

  17. Canal pattern in mesiobuccal root of maxillary molars of Nigerians ...

    African Journals Online (AJOL)

    planed maxillary first and second molars respectively were sectioned transversely at three different points corresponding to the cemento-enamel junction, the peak of the external outline of the furcation and the margin of the middle and apical thirds ...

  18. Impacted Mandibular Third Molars: Review of Literature and a ...

    African Journals Online (AJOL)

    Impacted tooth is a tooth which is completely or partially unerupted and is positioned against another tooth, bone or soft tissue so that its further eruption is unlikely, described according to its anatomic position.[1] The third molar impaction is occurring in about 73% of the young adults in Europe,[2] these teeth generally erupt ...

  19. Dental caries pattern of first and second permanent molars and ...

    African Journals Online (AJOL)

    Objective: The study was carried out to assess the dental caries pattern of first and second permanent molars and treatment needs among adolescent Nigerians in Lagos. Method: Examinations for dental caries and treatment needs in accordance with the criteria of the World Health Organization Basic Methods for oral ...

  20. internal root morphology in maxillary first permanent molars in a ...

    African Journals Online (AJOL)

    2011-03-03

    Mar 3, 2011 ... N. J. Muriithi, BDS (NBI), MDS, Prosthodontist, Ministry of Medical Services, Divisional of Oral Health, Rift Valley. Provincial Hospital, P. O. Box .... molars and satisfied the inclusion criteria were selected. The study was approved by the .... according to Vertucci classification. Type I. Type II. Type VII. Type VIII.

  1. Case report - Ectopic molar pregnancy: A case report | Bousfiha ...

    African Journals Online (AJOL)

    The patient was followed with weekly quantitative ;-hCG titers until three successive ;-hCG levels were negative. It is pertinent that clinicians take routine histological examination of tubal specimens in ectopic pregnancy very seriously in order to diagnose cases of ectopic molar gestations early and mount appropriate post ...

  2. ON THE MOLAR POLARIZABILITIES OF BINARY MIXTURES FROM ...

    African Journals Online (AJOL)

    TBA), lso-Propyl alcohol (IPA) and Toluene (TOL) were prepared at 298k and 1 atm. Subsequently, the densities, mole fractions and refractive indices of the mixtures and their pure components were obtained at 298k. The average molar ...

  3. internal root morphology in mandibular first permanent molars in a ...

    African Journals Online (AJOL)

    2013-11-06

    Nov 6, 2013 ... and for disinfection. Subsequently, the teeth were ... (70%, 95%, 100%) of ethyl alcohol (Scharlab S.L.. Sentmenat, Spain) for three ... Number of canals in mandibular first molars. 100. 90. 80. 70. 60. 50. 40. 30. 20. 10. 0. 3.2%.

  4. Variant Root Morphology of Third Mandibular Molar in Normal and ...

    African Journals Online (AJOL)

    isaac kipyator

    2017-11-12

    Nov 12, 2017 ... The mandibular third molar poses a challenge to dental surgeons due to it's unpredictable morphology which leads to increased difficulty during its .... Regeneration within the canal will thus be unimpeded unless obstructed by ... MATERIALS AND METHODS. A descriptive study was carried out at the.

  5. Taurodontism of deciduous and permanent molars: report of two cases.

    Science.gov (United States)

    Rao, Ashwin; Arathi, R

    2006-03-01

    Taurodontism is an aberration of teeth that lacks the constriction at the level of the CEJ characterized by elongated pulp chambers and apical displacement of bifurcation or trifurcation of the roots, giving it a rectangular shape. Its occurrence in permanent teeth is common and is quite rare in deciduous dentition. Presented in this article are two cases with taurodontism involving deciduous and permanent molars.

  6. A Rare Condition of Bimaxillary Primary Molar Taurodontism

    OpenAIRE

    Avula Jogendra Sai Sankar; Enuganti Sreedevi; Akkala Satya Gopal; Manne Naga Lakshmi

    2017-01-01

    Taurodontism is a relatively rare variance with a very low incidence in primary dentition and only a few cases have been reported in the literature. It stands a challenge when these teeth require pulp therapy. This case report illustrates the oral rehabilitation of multiple primary molars with taurodontism involving both the maxillary and mandibular arches, which is a rare occurrence.

  7. A Rare Condition of Bimaxillary Primary Molar Taurodontism.

    Science.gov (United States)

    Jogendra Sai Sankar, Avula; Sreedevi, Enuganti; Satya Gopal, Akkala; Naga Lakshmi, Manne

    2017-06-01

    Taurodontism is a relatively rare variance with a very low incidence in primary dentition and only a few cases have been reported in the literature. It stands a challenge when these teeth require pulp therapy. This case report illustrates the oral rehabilitation of multiple primary molars with taurodontism involving both the maxillary and mandibular arches, which is a rare occurrence.

  8. Temporal abscess after third molar extraction in the mandible.

    Science.gov (United States)

    de Oliveira Neto, Patrício José; de Souza Maliska, Maximiana Cristina; Sawazaki, Renato; Asprino, Luciana; de Moraes, Márcio; Moreira, Roger William Fernandes

    2012-03-01

    Dental infections resulting before or after third molar removal are complications in which the maxillofacial surgeon may have to initiate an earlier management. The severe dental infections resulting before or after this procedure is one of the few life-threatening complications in which the maxillofacial surgeon may have to initiate an earlier management. Infections involving the temporal space are rare and infrequently reported. Infections in this space have also been observed secondary to maxillary sinusitis, maxillary sinus fracture, temporomandibular arthroscopy, and drug injection, although more commonly associated to third molar infections. A 22-year-old man had undergone extraction of tooth 38 secondary to pericoronaritis by a general dentist. Physical examination of his face demonstrated severe trismus, pain, and swelling in temporal region. A CT scan showed an inflammatory area into the temporal space. He was started on IV cephalosporin, but the clinical course of the patient was not satisfactory. Incision and drainage were performed from an extraoral and intraoral approach. After discharged, the antibiotic was switched to clindamycin IO 600 mg. The retromaxillary and temporal infections are quite common after maxillary molar extractions but not after mandibular third molar, the spread mechanism of ascension must be involved with the virulence of microorganisms, but more studies are necessary to clarify this occurrence.

  9. Molar extinction coefficients of some carbohydrates in aqueous ...

    Indian Academy of Sciences (India)

    pp. 521–528. Molar extinction coefficients of some carbohydrates in aqueous solutions. K SINGH£, G K SANDHU, B S LARKa and S P SUDb. Department of Physics, Guru Nanak Dev University, Amritsar 143 005, India. aDepartment of Chemistry, Guru Nanak Dev University, Amritsar 143 005, India. bDepartment of Physics ...

  10. Molar extinction coefficients of solutions of some organic compounds

    Indian Academy of Sciences (India)

    were also fitted to third-order polynomial for all the carbohydrates of CnH2nOn type. Value of molar extinction coefficient is independent of the concentration of the solution as illustrated in figure 2. Using the present experimental data of mass attenuation coefficients of solutions and of H, C and O at different energies from ...

  11. Masticatory function following implants replacing a second molar.

    Science.gov (United States)

    Kim, Moon-Sun; Lee, Jae-Kwan; Chang, Beom-Seok; Um, Heung-Sik

    2011-04-01

    The aim of this study was to obtain objective and standardized information on masticatory function and patient satisfaction following second molar single implant therapy. Twenty adult patients, who had restored second molar single implants more than 1 month before the study, were enrolled in this study. All patients received a chewing test using peanuts before and after insertion of the implant prosthesis, with a questionnaire and visual analogue scale (VAS) to evaluate the effect of second molar single implant therapy. This study obtained standardized information on the masticatory function objectively (e.g., P, R, X(50)) before (Pre-insertion) and after insertion (Post-insertion) of the implant prosthesis. Masticatory performance (P) after insertion of the implant prosthesis significantly increased from 67.8±9.9 to 84.3±8.5% (Pmasticatory efficiency index (R) of Post-insertion is higher than that of Pre-insertion (Pfunctional point of view. These findings indicate that a second molar single implant can increase masticatory function.

  12. Inflammatory root resorption in primary molars: prevalence and associated factors.

    Science.gov (United States)

    Vieira-Andrade, Raquel Gonçalves; Drumond, Clarissa Lopes; Alves, Laura Pereira Azevedo; Marques, Leandro Silva; Ramos-Jorge, Maria Letícia

    2012-01-01

    This study aimed at determining the prevalence of inflammatory root resorption and associated factors in 1068 primary mandibular molars in 453 children 3 to 12 years of age. Age, dental history and medical history were recorded using a questionnaire administered to the children's parents/caregivers. Previously trained and calibrated examiners assessed radiographic images of the primary molars by direct observation, with the aid of a viewing box. Root resorption (physiological or inflammatory), dental crown status (healthy, carious with no pulp involvement, carious with pulp involvement and evidence of restoration), and pulpotomy or pulpectomy were determined. Data analysis involved descriptive statistics, the chi-square test and a multiple logistic regression (p pulpectomy (OR: 5.4; 95% CI) were risk factors for the occurrence of inflammatory root resorption in primary molars. In conclusion, the prevalence of inflammatory root resorption in the present sample was 16.2%. Gender, age, an unhealthy tooth, caries with pulp involvement, pulpotomy, pulpectomy, and the absence of a restoration were associated with a higher occurrence of inflammatory root resorption in primary molars.

  13. Inflammatory root resorption in primary molars: prevalence and associated factors

    Directory of Open Access Journals (Sweden)

    Raquel Gonçalves Vieira-Andrade

    2012-08-01

    Full Text Available This study aimed at determining the prevalence of inflammatory root resorption and associated factors in 1068 primary mandibular molars in 453 children 3 to 12 years of age. Age, dental history and medical history were recorded using a questionnaire administered to the children's parents/caregivers. Previously trained and calibrated examiners assessed radiographic images of the primary molars by direct observation, with the aid of a viewing box. Root resorption (physiological or inflammatory, dental crown status (healthy, carious with no pulp involvement, carious with pulp involvement and evidence of restoration, and pulpotomy or pulpectomy were determined. Data analysis involved descriptive statistics, the chi-square test and a multiple logistic regression (p < 0.05. The prevalence of inflammatory root resorption was 16.2% (n = 173. The male gender (OR: 1.4; 95% CI, the 3-to-7-years age bracket (OR: 1.5; 95% CI, an unhealthy dental crown (OR: 8.7; 95% CI, caries with pulp involvement (OR: 7.4; 95% CI, pulpotomy (OR: 3.1; 95% CI, and pulpectomy (OR: 5.4; 95% CI were risk factors for the occurrence of inflammatory root resorption in primary molars. In conclusion, the prevalence of inflammatory root resorption in the present sample was 16.2%. Gender, age, an unhealthy tooth, caries with pulp involvement, pulpotomy, pulpectomy, and the absence of a restoration were associated with a higher occurrence of inflammatory root resorption in primary molars.

  14. Permanent versus temporary restorations after emergency pulpotomies in primary molars.

    Science.gov (United States)

    Guelmann, Marcio; Fair, Jodi; Bimstein, Enrique

    2005-01-01

    The purpose of this retrospective study was to determine if immediate placement of a stainless steel crown (SSC) after emergency pulpotomies in primary molars would result in a better outcome when compared to different temporary restorations. Records of 94 emergency pulpotomies in primary molars performed at a university pediatric graduate dental clinic between July 2001 and June 2004 were analyzed. Inclusion criteria included: (1) teeth with a positive history of spontaneous or elicited pain; (2) deep caries with close approximation to the pulp; (3) absence of clinical and radiographic signs of pulpal degeneration; (4) abnormal mobility; or (5) swelling. Pulpotomized teeth were temporarily restored with a zinc oxide eugenol-based temporary restoration (IRM) covered with Ketac Molar or with a permanent restoration (SSC). The time interval between emergency and definitive treatment or recall, age, gender, tooth type, and arch were the variables analyzed in the study. Success was determined by record (progress notes and radiographs) verification of SSC placement in case of a temporary restoration and by confirmation of crown presence during recall exam. Data from emergency pulpotomies restored only with IRM was added to the study and included in the statistical analysis. Superior clinical success was obtained when emergency pulpotomies were restored with SSC (86%) when compared to IRM only (61%) or IRM and Ketac Molar combined (77%). Statistical significance was obtained in favor of SSC when survival analysis was performed (P.05). Immediate placement of an SSC tended to improve the chances for success when emergency pulpotomies are performed.

  15. Impacted third molar transplantation on the malpracticed extraction ...

    African Journals Online (AJOL)

    ... followed after transplant for a four-year period with the best satisfaction. Funding: A grant of the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea. (HI15C0689). Keywords: Autotransplantation, Endodontic treatment, Impacted third molar, Malpracticed extraction, Maxillofacial specialty ...

  16. Evaluation of radiographic features of embedded primary molar ...

    African Journals Online (AJOL)

    2014-05-20

    May 20, 2014 ... should be alert to this possibility and should perform a thorough clinical and radiographic examination. If these primary molar roots are allowed to remain in the oral cavity, periodontist should be aware of their presence and modify the treatment plan accordingly.[13]. Differential diagnosis of retained roots ...

  17. Miniscrew-supported coil spring for molar uprighting: description

    Directory of Open Access Journals (Sweden)

    Antônio Carlos de Oliveira Ruellas

    2013-02-01

    Full Text Available INTRODUCTION: Since the beginning of miniscrews as orthodontic anchorage, many applications have been described in the literature. Among these, one is the uprighting of mesially inclined molars. In regard to the mechanical aspects, however, there is little information about the application of orthodontic forces using such devices. OBJECTIVE: The objective of this study was to describe a miniscrew supported spring for uprighting of mesially inclined molars. With this device, one can achieve the correct use of orthodontic biomechanics, thus favoring more predictable tooth movements and preventing unwanted movements from occurring.INTRODUÇÃO: desde o surgimento dos mini-implantes como recurso de ancoragem ortodôntica, muitas aplicações têm sido descritas na literatura. Entre essas, cita-se a verticalização de molares inclinados para mesial. No entanto, pouco se fala da correta aplicação das forças ortodônticas nesses dispositivos, sob o ponto de vista mecânico. OBJETIVOS: o objetivo desse artigo foi demonstrar uma mola mini-implante suportada para verticalizar molares inclinados para mesial. Com esse dispositivo consegue-se correta aplicação da mecânica ortodôntica, favorecendo movimentos mais previsíveis e minimizando os movimentos indesejáveis.

  18. Risk for molars without antagonists: opinion of dental practitioners in ...

    African Journals Online (AJOL)

    Results: The great majority of practitioners (92%) believed that unopposed molars overerupt markedly and majority (87%) recommends replacement of the missing antagonist with partial dentures while 13% preferred to wait and see. The main reasons for the suggested treatment were (1) to prevent overeruption of ...

  19. Geometric morphometric analysis of the molars in three species of ...

    African Journals Online (AJOL)

    The relatively new technique of outline-based geometric morphometrics was applied in a study of the variation in the shape of the upper and lower molars among 122 mice, belonging to one species from Iran (Mus musculus) and two species from Europe (Mus macedonicus, Mus spicilegus). Differentiation of specimens ...

  20. Antibiotic prophylaxis in third molar surgery: a review

    NARCIS (Netherlands)

    Oomens, M.A.E.; Forouzanfar, T.

    2012-01-01

    Objective: Controversy exists about the efficacy of antibiotic prophylaxis in preventing complications after lower third molar surgery. For evidence-based recommendation, a review was performed on clinical trials reporting the use of antibiotic prophylaxis compared with no treatment or placebo with