Anomalous enthalpy relaxation in vitreous silica

DEFF Research Database (Denmark)

Yue, Yuanzheng

2015-01-01

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...... the fragile ones do in a structurally independent fashion. We discuss the origin of the anomalous enthalpy relaxation in the HQ vitreous silica....

Enthalpies of a binary alloy during solidification

Science.gov (United States)

Poirier, D. R.; Nandapurkar, P.

1988-01-01

The purpose of the paper is to present a method of calculating the enthalpy of a dendritic alloy during solidification. The enthalpies of the dendritic solid and interdendritic liquid of alloys of the Pb-Sn system are evaluated, but the method could be applied to other binaries, as well. The enthalpies are consistent with a recent evaluation of the thermodynamics of Pb-Sn alloys and with the redistribution of solute in the same during dendritic solidification. Because of the heat of mixing in Pb-Sn alloys, the interdendritic liquid of hypoeutectic alloys (Pb-rich) of less than 50 wt pct Sn has enthalpies that increase as temperature decreases during solidification.

Standard molar enthalpy of formation of methoxyacetophenone isomers

International Nuclear Information System (INIS)

Amaral, Luísa M.P.F.; Morais, Victor M.F.; Ribeiro da Silva, Manuel A.V.

2014-01-01

Highlights: • Experimental and computational energetic study of methoxyacetophenone isomers. • Enthalpies of formation and phase transition determined by calorimetric techniques. • Quantum chemical calculations allowed estimation of enthalpies of formation. • Structure and energy correlations were established. - Abstract: Values of the standard (p o = 0.1 MPa) molar enthalpy of formation of 2′-, 3′- and 4′-methoxyacetophenones were derived from their standard molar energy 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/vaporization of the compounds studied. 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 the standard molar enthalpies for the phase transition. The results obtained are −(232.0 ± 2.5), −(237.7 ± 2.7) and −(241.1 ± 2.1) kJ · mol −1 for 2′-, 3′- and 4′-methoxyacetophenone, respectively. Standard molar enthalpies of formation were also estimated from different methodologies: the Cox scheme as well as two different computational approaches using density functional theory-based B3LYP and the multilevel G3 methodologies

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

Calibration models for high enthalpy calorimetric probes.

Science.gov (United States)

Kannel, A

1978-07-01

The accuracy of gas-aspirated liquid-cooled calorimetric probes used for measuring the enthalpy of high-temperature gas streams is studied. The error in the differential temperature measurements caused by internal and external heat transfer interactions is considered and quantified by mathematical models. The analysis suggests calibration methods for the evaluation of dimensionless heat transfer parameters in the models, which then can give a more accurate value for the enthalpy of the sample. Calibration models for four types of calorimeters are applied to results from the literature and from our own experiments: a circular slit calorimeter developed by the author, single-cooling jacket probe, double-cooling jacket probe, and split-flow cooling jacket probe. The results show that the models are useful for describing and correcting the temperature measurements.

New experimental heat capacity and enthalpy of formation of lithium cobalt oxide

International Nuclear Information System (INIS)

Gotcu-Freis, Petronela; Cupid, Damian M.; Rohde, Magnus; Seifert, Hans J.

2015-01-01

Highlights: • LiCoO 2 heat capacity was measured in the temperature range (160 to 953) K using DSC. • Continuous/discontinuous methods were applied on different types of calorimeters. • Enthalpy increment of LiCoO 2 was determined using drop calorimetry at T = 974 K. • Enthalpies of formation were evaluated from oxide melt drop solution calorimetry. - Abstract: The heat capacity of LiCoO 2 (O3-phase), constituent material in cathodes for lithium-ion batteries, was measured using two differential scanning calorimeters over the temperature range from (160 to 953) K (continuous method). As an alternative, the discontinuous method was employed over the temperature range from (493 to 693) K using a third calorimeter. Based on the results obtained, the enthalpy increment of LiCoO 2 was derived from T = 298.15 K up to 974.15 K. Very good agreement was obtained between the derived enthalpy increment and our independent measurements of enthalpy increment using transposed temperature drop calorimetry at 974.15 K. In addition, values of the enthalpy of formation of LiCoO 2 from the constituent oxides and elements were assessed based on measurements of enthalpy of dissolution using high temperature oxide melt drop solution calorimetry. The high temperature values obtained by these measurements are key input data in safety analysis and optimisation of the battery management systems which accounts for possible thermal runaway events

Enthalpy of mixing of liquid Co–Sn alloys

International Nuclear Information System (INIS)

Yakymovych, A.; Fürtauer, S.; Elmahfoudi, A.; Ipser, H.; Flandorfer, H.

2014-01-01

Highlights: • The enthalpies of mixing of liquid Co–Sn alloys between T = (673 and 1773) K. • The temperature dependence of the enthalpies of mixing was described. • Full report of measured values including polynomial coefficients. - Abstract: A literature overview of enthalpy of mixing data for liquid Co–Sn alloys shows large scattering but no clear temperature dependence. Therefore drop calorimetry was performed in the Co–Sn system at twelve different temperatures in 100 K steps in the temperature range (673 to 1773) K. The integral enthalpy of mixing was determined starting from 1173 K and fitted to a standard Redlich–Kister polynomial. In addition, the limiting partial molar enthalpy of Co in Sn was investigated by small additions of Co to liquid Sn at temperatures (673 to 1773) K. The integral and partial molar enthalpies of the Co–Sn system generally show an exothermic mixing behavior. Significant temperature dependence was detected for the enthalpies of mixing. The minimum integral enthalpy values vary with rising temperature from approx. −7820 J/mol at T = 1173 K to −1350 J/mol at T = 1773 K; the position of the minimum is between (59 and 61) at.% Co. The results are discussed and compared with literature data available for this system. X-ray studies and scanning electron microscopy of selected alloys obtained from the calorimetric measurements were carried out in order to check the completeness of the solution process

Formation enthalpy of alkali-borosilicate glass

International Nuclear Information System (INIS)

Borisova, N.V.; Ushakov, V.M.

1991-01-01

Temperature dependence of formation enthalpy of glass of the composition 0.0438Na 2 O-0.0385K 2 O-0.3394B 2 O 3 -0.5783SiO 2 was determined using the method of high-temperature colorimetry-dissolution, mixing and differential scanning calorimetry. The glass considered has liquation nature-two-vitrification ranges at 713 K and 817 K are detected. The brightening point is 922 K. The calculation of formation enthalpy using the method of partial heat capacities is made in the temperature range of 973-1473 K. Formation enthalpy does not depend on temperature in the temperature range of 298-1273 K

Direct determination of enthalpies of solid phase reactions by immersion method; Determination directe des enthalpies de reaction en phase solide par une methode de plongee

Energy Technology Data Exchange (ETDEWEB)

Roux, A; Richard, M; Eyraud, L; Stevanovic, M; Elston, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1967-07-01

It is not generally possible to measure the enthalpy change corresponding to solid phase reactions using the dynamic differential thermal analysis method because these reactions are usually too slow at the temperature of operation of present equipment. A ballistic differential thermal analysis apparatus has been developed which is based on an immersion-compensation method; it overcomes the difficulties previously encountered. This apparatus has been used after calibration for determining the enthalpies of formation of calcium and cadmium titanates. and also the Wigner energies of BeO, MgO and Al{sub 2}O{sub 3} samples irradiated at variable dose at a temperature of under 100 deg. C. (authors) [French] Il n'est generalement pas possible de mesurer la variation d'enthalpie correspondant aux reactions en phase solide par la methode d'analyse thermique differentielle dynamique. En effet, ces reactions sont le plus souvent trop lentes aux temperatures d'utilisation des dispositifs actuels. Un appareil d'analyse thermique differentielle balistique, base sur une methode de plongee avec compensation, a ete mis au point et permet de surmonter les difficultes precedentes. Apres etalonnages, cet appareil a ete utilise pour la determination des enthalpies de formation du titanate de calcium et du titanate de cadmium ainsi que pour celle des energies Wigner emmagasinees dans des echantillons de BeO, MgO et Al{sub 2}O{sub 3} irradies a une temperature inferieure a 100 deg. C et a differentes doses. (auteurs)

Thermochemistry of methoxythiophenes: Measurement of their enthalpies of vaporization and estimation of their enthalpies of formation in the condensed phase

International Nuclear Information System (INIS)

Temprado, Manuel; Notario, Rafael; Roux, María Victoria; Verevkin, Sergey P.

2014-01-01

Highlights: • The enthalpies of vaporization of 2- and 3-methoxythiophenes have been measured by the transpiration method. • We have estimated the enthalpies of formation of methoxythiophenes in liquid phase. • The optimized geometries of methoxythiophenes have been tabulated and compared with the experimental crystal structures. - Abstract: Enthalpies of vaporization of 2- and 3-methoxythiophenes (48.32 ± 0.30 and 48.54 ± 0.22 kJ · mol −1 , respectively) have been measured by the transpiration method using nitrogen as the carrying and protecting stream. Combustion experiments leading to enthalpies of formation in the liquid phase, Δ f H 0 m (l), for both isomers failed due to rapid darkening of freshly distilled samples even under a protecting atmosphere. However, combination of experimental vaporization enthalpies with values of the gaseous enthalpies of formation, Δ f H 0 m (g), obtained by quantum-chemical calculations from our previous work Notario et al. (2012) [24] permits establishing estimated Δ f H 0 m (l) values of −(68.3 ± 4.2) and −(80.1 ± 4.2) kJ · mol −1 , for 2- and 3-methoxythiophene, respectively

Calculating the enthalpy of vaporization for ionic liquid clusters.

Science.gov (United States)

Kelkar, Manish S; Maginn, Edward J

2007-08-16

Classical atomistic simulations are used to compute the enthalpy of vaporization of a series of ionic liquids composed of 1-alkyl-3-methylimidazolium cations paired with the bis(trifluoromethylsulfonyl)imide anion. The calculations show that the enthalpy of vaporization is lowest for neutral ion pairs. The enthalpy of vaporization increases by about 40 kJ/mol with the addition of each ion pair to the vaporizing cluster. Non-neutral clusters have much higher vaporization enthalpies than their neutral counterparts and thus are not expected to make up a significant fraction of volatile species. The enthalpy of vaporization increases slightly as the cation alkyl chain length increases and as temperature decreases. The calculated vaporization enthalpies are consistent with two sets of recent experimental measurements as well as with previous atomistic simulations.

A DFT study on the enthalpies of thermite reactions and enthalpies of formation of metal composite oxide

Science.gov (United States)

Zhang, Yu-ying; Wang, Meng-jie; Chang, Chun-ran; Xu, Kang-zhen; Ma, Hai-xia; Zhao, Feng-qi

2018-05-01

The standard thermite reaction enthalpies (ΔrHmθ) for seven metal oxides were theoretically analyzed using density functional theory (DFT) under five different functional levels, and the results were compared with experimental values. Through the comparison of the linear fitting constants, mean error and root mean square error, the Perdew-Wang functional within the framework of local density approximation (LDA-PWC) and Perdew-Burke-Ernzerhof exchange-correlation functional within the framework of generalized gradient approximation (GGA-PBE) were selected to further calculate the thermite reaction enthalpies for metal composite oxides (MCOs). According to the Kirchhoff formula, the standard molar reaction enthalpies for these MCOs were obtained and their standard molar enthalpies of formation (ΔfHmθ) were finally calculated. The results indicated that GGA-PBE is the most suitable one out of the total five methods to calculate these oxides. Tungstate crystals present the maximum deviation of the enthalpies of thermite reactions for MCOs and these of their physical metal oxide mixtures, but ferrite crystals are the minimum. The correlation coefficients are all above 0.95, meaning linear fitting results are very precise. And the molar enthalpies of formation for NiMoO4, CuMoO4, PbZrO3 (Pm/3m), PbZrO3 (PBA2), PbZrO3 (PBam), MgZrO3, CdZrO3, MnZrO3, CuWO4 and Fe2WO6 were first obtained as -1078.75, -1058.45, -1343.87, -1266.54, -1342.29, -1333.03, -1210.43, -1388.05, -1131.07 and - 1860.11 kJ·mol-1, respectively.

Enthalpies of Formation of Hydrazine and Its Derivatives.

Science.gov (United States)

Dorofeeva, Olga V; Ryzhova, Oxana N; Suchkova, Taisiya A

2017-07-20

Enthalpies of formation, Δ f H 298 ° , in both the gas and condensed phase, and enthalpies of sublimation or vaporization have been estimated for hydrazine, NH 2 NH 2 , and its 36 various derivatives using quantum chemical calculations. The composite G4 method has been used along with isodesmic reaction schemes to derive a set of self-consistent high-accuracy gas-phase enthalpies of formation. To estimate the enthalpies of sublimation and vaporization with reasonable accuracy (5-20 kJ/mol), the method of molecular electrostatic potential (MEP) has been used. The value of Δ f H 298 ° (NH 2 NH 2 ,g) = 97.0 ± 3.0 kJ/mol was determined from 75 isogyric reactions involving about 50 reference species; for most of these species, the accurate Δ f H 298 ° (g) values are available in Active Thermochemical Tables (ATcT). The calculated value is in excellent agreement with the reported results of the most accurate models based on coupled cluster theory (97.3 kJ/mol, the average of six calculations). Thus, the difference between the values predicted by high-level theoretical calculations and the experimental value of Δ f H 298 ° (NH 2 NH 2 ,g) = 95.55 ± 0.19 kJ/mol recommended in the ATcT and other comprehensive reference sources is sufficiently large and requires further investigation. Different hydrazine derivatives have been also considered in this work. For some of them, both the enthalpy of formation in the condensed phase and the enthalpy of sublimation or vaporization are available; for other compounds, experimental data for only one of these properties exist. Evidence of accuracy of experimental data for the first group of compounds was provided by the agreement with theoretical Δ f H 298 ° (g) value. The unknown property for the second group of compounds was predicted using the MEP model. This paper presents a systematic comparison of experimentally determined enthalpies of formation and enthalpies of sublimation or vaporization with the results of

EzArray: A web-based highly automated Affymetrix expression array data management and analysis system

Directory of Open Access Journals (Sweden)

Zhu Yuelin

2008-01-01

Full Text Available Abstract Background Though microarray experiments are very popular in life science research, managing and analyzing microarray data are still challenging tasks for many biologists. Most microarray programs require users to have sophisticated knowledge of mathematics, statistics and computer skills for usage. With accumulating microarray data deposited in public databases, easy-to-use programs to re-analyze previously published microarray data are in high demand. Results EzArray is a web-based Affymetrix expression array data management and analysis system for researchers who need to organize microarray data efficiently and get data analyzed instantly. EzArray organizes microarray data into projects that can be analyzed online with predefined or custom procedures. EzArray performs data preprocessing and detection of differentially expressed genes with statistical methods. All analysis procedures are optimized and highly automated so that even novice users with limited pre-knowledge of microarray data analysis can complete initial analysis quickly. Since all input files, analysis parameters, and executed scripts can be downloaded, EzArray provides maximum reproducibility for each analysis. In addition, EzArray integrates with Gene Expression Omnibus (GEO and allows instantaneous re-analysis of published array data. Conclusion EzArray is a novel Affymetrix expression array data analysis and sharing system. EzArray provides easy-to-use tools for re-analyzing published microarray data and will help both novice and experienced users perform initial analysis of their microarray data from the location of data storage. We believe EzArray will be a useful system for facilities with microarray services and laboratories with multiple members involved in microarray data analysis. EzArray is freely available from http://www.ezarray.com/.

Experimental evaluation of enthalpy efficiency and gas-phase contaminant transfer in an enthalpy recovery unit with polymer membrane foils

DEFF Research Database (Denmark)

Nie, Jinzhe; Yang, Jianrong; Fang, Lei

2015-01-01

Experimental studies were conducted in a laboratory setting to investigate the enthalpy efficiency and gas-phase contaminant transfer in a polymer membrane enthalpy recovery unit. One commercially available polymer membrane enthalpy recovery unit was used as a reference unit. Simulated indoor air...... and outdoor air by twin chambers was connected to the unit. Three chemical gases were dosed to the indoor exhaust air to mimic indoor air contaminants. Based on the measurements of temperature, humidity ratio, and contaminant concentrations of the indoor exhaust air and outdoor air supply upstream...

Standard molar enthalpies of formation of monochloroacetophenone isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.

2010-01-01

The standard (p 0 =0.1MPa) molar enthalpies of formation of the liquids 2'-, 3'-, and 4'-chloroacetophenones were derived from the standard molar energies of combustion, in oxygen, to yield CO 2 (g) and HCl . 600H 2 O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet microcalorimetry was used to measure the enthalpies of vaporization of the three compounds. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the chloroacetophenone isomers, in the gaseous phase, at T = 298.15 K. (table) An empirical scheme, developed by Cox, was used to estimate the gas-phase enthalpies of formation and the obtained values were compared with the experimental ones.

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.

Enthalpy generation from mixing in hohlraum-driven targets

Science.gov (United States)

Amendt, Peter; Milovich, Jose

2016-10-01

The increase in enthalpy from the physical mixing of two initially separated materials is analytically estimated and applied to ICF implosions and gas-filled hohlraums. Pressure and temperature gradients across a classical interface are shown to be the origin of enthalpy generation from mixing. The amount of enthalpy generation is estimated to be on the order of 100 Joules for a 10 micron-scale annular mixing layer between the solid deuterium-tritium fuel and the undoped high-density carbon ablator of a NIF-scale implosion. A potential resonance is found between the mixing layer thickness and gravitational (Cs2/ g) and temperature-gradient scale lengths, leading to elevated enthalpy generation. These results suggest that if mixing occurs in current capsule designs for the National Ignition Facility, the ignition margin may be appreciably eroded by the associated enthalpy of mixing. The degree of enthalpy generation from mixing of high- Z hohlraum wall material and low- Z gas fills is estimated to be on the order of 100 kJ or more for recent NIF-scale hohlraum experiments, which is consistent with the inferred missing energy based on observed delays in capsule implosion times. Work performed under the auspices of Lawrence Livermore National Security, LLC (LLNS) under Contract No. DE-AC52-07NA27344.

Enthalpies of vaporization of organometallic compounds

International Nuclear Information System (INIS)

Kuznetsov, N.T.; Sevast'yanov, V.G.; Mitin, V.A.; Krasnodubskaya, S.V.; Zakharov, L.N.; Domrachev, G.A.; AN SSSR, Gor'kij. Inst. Khimii)

1987-01-01

A possibility to use the method of additive schemes for the calculation of vaporizaton enthalpies of uranium organometallic compounds is discussed while comparing the values obtained using the method with experimental data. The possibility of apriori evaluation of evaporation enthalpy values of different uranium compounds using the method of additive schemes and structural characteristics of molecules, such as the sum of ligand solid angles, is shown

Study on the enthalpy of solution and enthalpy of dilution for the ionic liquid [C3mim][Val] (1-propyl-3-methylimidazolium valine)

International Nuclear Information System (INIS)

Guan Wei; Li Long; Ma Xiaoxue; Tong Jing; Fang Dawei; Yang Jiazhen

2012-01-01

Graphical abstract: The thermodynamic cycle for estimation of the hydration enthalpy of ionic liquid [C 3 mim][Val]. Highlights: ► A new amino acid ionic liquid [C 3 mim][Val] was prepared. ► The molar enthalpies of solution of the ionic liquid. ► The hydration enthalpy of the cation [C 3 mim] + was estimated. ► The molar enthalpies of dilution, of aqueous [C 3 mim][Val] were measured. - Abstract: A new amino acid ionic liquid (AAIL) [C 3 mim][Val] (1-propyl-3-methylimidazolium valine) was prepared by the neutralization method. Using the solution-reaction isoperibol calorimeter, molar solution enthalpies of the ionic liquid [C 3 mim][Val] with known amounts of water and with different concentrations in molality were measured at T = 298.15 K. In terms of standard addition method (SAM) and Archer’s method, the standard molar enthalpy of solution for [C 3 mim][Val] without water, Δ s H m ∘ = (−55.7 ± 0.4) kJ · mol −1 , was obtained. The hydration enthalpy of the cation [C 3 mim] + , ΔH + ([C 3 mim] + ) = −226 kJ · mol −1 , was estimated in terms of Glasser’s theory. Using the RD496-III heat conduction microcalorimeter, the molar enthalpies of dilution, Δ D H m (m i → m f ), of aqueous [C 3 mim][Val] with various values of molality were measured. The values of Δ D H m (m i → m f ) were fitted to Pitzer’s ion-interaction model and the values of apparent relative molar enthalpy, φ L, calculated using Pitzer’s ion-interaction model.

Relationships between fusion, solution, vaporization and sublimation enthalpies of substituted phenols

International Nuclear Information System (INIS)

Yagofarov, Mikhail I.; Nagrimanov, Ruslan N.; Solomonov, Boris N.

2017-01-01

Highlights: • Method for determination of sublimation and vaporization enthalpies of phenols was developed. • Vaporization enthalpies of 28 phenols at 298 K were calculated. • Sublimation enthalpies of 26 phenols at 298 K were calculated using fusion enthalpies at melting temperatures. • Obtained values are in good agreement with the results of conventional methods. - Abstract: In this work a method for determination of sublimation and vaporization enthalpies of substituted phenols was developed. This method is a modification of solution calorimetry approach. Modification is based on the novel relations, which bind solution, vaporization and sublimation enthalpies at 298.15 K and fusion enthalpy at the melting temperature. According to novel relations the equations for calculating sublimation and vaporization enthalpies at 298.15 K were offered. Calculated values of sublimation and vaporization enthalpies of phenol derivatives containing alkyls, halogens, –OCH 3 , –NO 2 , –COCH 3 , –COOCH 3 groups, and dihydroxybenzenes were compared with literature data (298.15 K) obtained by conventional methods. In most of the cases divergence does not exceed 2–3%.

Standard molar enthalpies of formation of monochloroacetophenone isomers

Energy Technology Data Exchange (ETDEWEB)

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

2010-12-15

The standard (p{sup 0}=0.1MPa) molar enthalpies of formation of the liquids 2'-, 3'-, and 4'-chloroacetophenones were derived from the standard molar energies of combustion, in oxygen, to yield CO{sub 2}(g) and HCl . 600H{sub 2}O(l), at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The Calvet microcalorimetry was used to measure the enthalpies of vaporization of the three compounds. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the chloroacetophenone isomers, in the gaseous phase, at T = 298.15 K. (table) An empirical scheme, developed by Cox, was used to estimate the gas-phase enthalpies of formation and the obtained values were compared with the experimental ones.

Enthalpy of dissociation and hydration number of methane hydrate from the Clapeyron equation

International Nuclear Information System (INIS)

Anderson, Graydon K.

2004-01-01

The enthalpies of the reactions in which methane hydrate is dissociated to methane vapor and either (1) water, or (2) ice are determined by a new analysis using the Clapeyron equation. The difference in enthalpies of the two reactions is used to infer the hydration number at the quadruple point where hydrate, ice, liquid water, and methane vapor coexist. By appropriate corrections, the hydration number at points removed from the quadruple point is also determined. The most important feature of the new analysis is the direct use of the Clapeyron equation. The method avoids the use of certain simplifying assumptions that have compromised the accuracy of previous analyses in which the Clausius-Clapeyron equation was used. The analysis takes into account the finite volumes of all phases, the non-ideality of the vapor phase, and the solubility of methane in water. The results show that the enthalpy of dissociation and hydration number are constant within experimental error over the entire (hydrate, liquid, vapor) coexistence region. The results are more accurate than but entirely consistent with almost all previous studies

Determination of the vacancy formation enthalpy for high purity Ni

International Nuclear Information System (INIS)

Lynn, K.G.; Snead, C.L. Jr.; Hurst, J.J.; Farrell, K.

1979-01-01

Positron-annihilation lifetime measurements have been made on Ni over a temperature range of 4.2 to 1700 K. We find a small change in the lifetime from 4.2 to 900 K indicating a very small thermal-expansion effect. A small precursor effect is observed before the onset of significant vacancy trapping. A monovacancy formation enthalpy of 1.54/sub +0.2//sup -0.1/ eV is extracted without taking divacancies into consideration in the analysis. No detrapping from mono-vacancies is observed even at the higher temperatures. The vacancy formation enthalpy extracted from the lifetime data is compared to values obtained by Doppler-broadening and angular-correlation techniques

Determination of the vacancy formation enthalpy for high purity Ni

International Nuclear Information System (INIS)

Lynn, K.G.; Snead, C.L. Jr.; Hurst, J.J.; Farrell, K.

1979-01-01

Positron-annihilation lifetime measurements have been made on Ni over a temperature range of 4.2 to 1700 K. We find a small change in the lifetime from 4.2 - 900 K indicating a very small thermal-expansion effect. A small precursor effect is observed before the onset of significant vacancy trapping. A monovacancy formation enthalpy of 1.54sub(+0.2)sup(-0.1) eV is extracted without taking divacancies into consideration in the analysis. No detrapping from mono-vacancies is observed even at the higher temperatures. The vacancy formation enthalpy extracted from the lifetime data is compared to values obtained by Doppler-broadening and angular-correlation techniques. (author)

Enthalpy of formation of anisole: implications for the controversy on the O-H bond dissociation enthalpy in phenol.

Science.gov (United States)

Simões, Ricardo G; Agapito, Filipe; Diogo, Hermínio P; da Piedade, Manuel E Minas

2014-11-20

Significant discrepancies in the literature data for the enthalpy of formation of gaseous anisole, ΔfHmo(PhOCH3, g), have fueled an ongoing controversy regarding the most reliable enthalpy of formation of the phenoxy radical and of the gas phase O-H bond dissociation enthalpy, DHo(PhO-H), in phenol. In the present work ΔfHmo(PhOCH3, g) was reassessed using a combination of calorimetric determinations and high-level (W2-F12) ab initio calculations. Static-bomb combustion calorimetry led to the standard molar enthalpy of formation of liquid anisole at 298.15 K, ΔfHmo(PhOCH3, l) = −(117.1 ± 1.4) kJ·mol(-1). The corresponding enthalpy of vaporization was obtained as, ΔvapHmo(PhOCH3) = 46.41 ± 0.26 kJ·mol(-1), by Calvet-drop microcalorimetry. These results give ΔfHmo(PhOCH3, g) = −(70.7 ± 1.4) kJ·mol(-1), in excellent agreement with ΔfHmo(PhOCH3, g) = −(70.8 ± 3.2) kJ·mol(-1), obtained from the W2-F12 calculations. The ΔfHmo(PhOCH3, g) here recommended leads to ΔfHmo(PhO•, g) = 55.5 ± 2.4 kJ·mol(-)1 and DH°(PhO-H) = 368.1 ± 2.6 kJ·mol(-1).

The thermochemistry of 2,4-pentanedione revisited: observance of a nonzero enthalpy of mixing between tautomers and its effects on enthalpies of formation.

Science.gov (United States)

Temprado, Manuel; Roux, Maria Victoria; Umnahanant, Patamaporn; Zhao, Hui; Chickos, James S

2005-06-30

The enthalpies of formation of pure liquid and gas-phase (Z)-4-hydroxy-3-penten-2-one and 2,4-pentanedione are examined in the light of some more recent NMR studies on the enthalpy differences between gas-phase enthalpies of the two tautomers. Correlation gas chromatography experiments are used to evaluate the vaporization enthalpies of the pure tautomers. Values of (51.2 +/- 2.2) and (50.8 +/- 0.6) kJ.mol(-1) are measured for pure 2,4-pentanedione and (Z)-4-hydroxy-3-penten-2-one, respectively. The value of (50.8 +/- 0.6) kJ.mol(-1) can be contrasted to a value of (43.2 +/- 0.2) kJ.mol(-1) calculated for pure (Z)-4-hydroxy-3-penten-2-one when the vaporization enthalpy is measured in a mixture of tautomers. The difference is attributed to an endothermic enthalpy of mixing that destabilizes the mixture relative to the pure components. Calculation of new enthalpies of formation for (Z)-4-hydroxy-3-penten-2-one and 2,4-pentanedione in both the gas, Delta(f)H degrees (m)(g) = (-378.2 +/- 1.2) and (-358.9 +/- 2.5) kJ.mol(-1), respectively, and liquid phases, Delta(f)H degrees (m)(l) = (-429.0 +/- 1.0) and (-410.1 +/- 1.2) kJ.mol(-1), respectively, results in enthalpy differences between the two tautomers both in the liquid and gas phases that are identical within experimental error, and in excellent agreement with recent gas-phase NMR studies.

The relationship between vapour pressure, vaporization enthalpy, and enthalpy of transfer from solution to gas: An extension of the Martin equation

International Nuclear Information System (INIS)

Srisaipet, A.; Aryusuk, K.; Lilitchan, S.; Krisnangkura, K.

2007-01-01

Martin's equation, Δ sln g G=Δ sln g G o +zδ sln g G, is extended to cover vaporization free energy (Δ l g G). The extended equation is further expanded in terms of enthalpy and entropy and then used to correlate vaporization enthalpy (Δ l g H) and enthalpy of transfer from solution to gas (Δ sln g H). Data available in the literatures are used to validate and support the speculations derived from the proposed equation

Enthalpy of sublimation as measured using a silicon oscillator

Science.gov (United States)

Shakeel, Hamza; Pomeroy, J. M.

In this study, we report the enthalpy of sublimation of common gases (nitrogen, oxygen, argon, carbon dioxide, neon, krypton, xenon, and water vapor) using a large area silicon oscillator with a sub-ng (~0.027 ng/cm2) mass sensitivity. The double paddle oscillator design enables high frequency stability (17 ppb) at cryogenic temperatures and provides a consistent technique for enthalpy measurements. The enthalpies of sublimation are derived from the rate of mass loss during programmed thermal desorption and are detected as a change in the resonance frequency of the self-tracking oscillator. These measured enthalpy values show excellent agreement with the accepted literature values.

Leakage analysis of crossbar memristor arrays

KAUST Repository

Zidan, Mohammed A.

2014-07-01

Crossbar memristor arrays provide a promising high density alternative for the current memory and storage technologies. These arrays suffer from parasitic current components that significantly increase the power consumption, and could ruin the readout operation. In this work we study the trade-off between the crossbar array density and the power consumption required for its readout. Our analysis is based on simulating full memristor arrays on a SPICE platform.

Vapor pressures and enthalpies of vaporization of azides

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Emel'yanenko, Vladimir N.; Algarra, Manuel; Manuel Lopez-Romero, J.; Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G.

2011-01-01

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 Δ l g H 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.

Microbial Diagnostic Array Workstation (MDAW: a web server for diagnostic array data storage, sharing and analysis

Directory of Open Access Journals (Sweden)

Chang Yung-Fu

2008-09-01

Full Text Available Abstract Background Microarrays are becoming a very popular tool for microbial detection and diagnostics. Although these diagnostic arrays are much simpler when compared to the traditional transcriptome arrays, due to the high throughput nature of the arrays, the data analysis requirements still form a bottle neck for the widespread use of these diagnostic arrays. Hence we developed a new online data sharing and analysis environment customised for diagnostic arrays. Methods Microbial Diagnostic Array Workstation (MDAW is a database driven application designed in MS Access and front end designed in ASP.NET. Conclusion MDAW is a new resource that is customised for the data analysis requirements for microbial diagnostic arrays.

Enthalpy-entropy compensation and the isokinetic temperature in ...

Indian Academy of Sciences (India)

Enthalpy-entropy compensation supposes that differences in activation enthalpy delta-H-++ for different reactions (or, typically inbiochemistry, the same reaction catalysed by enzymes obtained from different species) may be compensated for bydifferences in activation entropy delta-S-++. At the isokinetic temperature the ...

Nanoelectrode array for electrochemical analysis

Energy Technology Data Exchange (ETDEWEB)

Yelton, William G [Sandia Park, NM; Siegal, Michael P [Albuquerque, NM

2009-12-01

A nanoelectrode array comprises a plurality of nanoelectrodes wherein the geometric dimensions of the electrode controls the electrochemical response, and the current density is independent of time. By combining a massive array of nanoelectrodes in parallel, the current signal can be amplified while still retaining the beneficial geometric advantages of nanoelectrodes. Such nanoelectrode arrays can be used in a sensor system for rapid, non-contaminating field analysis. For example, an array of suitably functionalized nanoelectrodes can be incorporated into a small, integrated sensor system that can identify many species rapidly and simultaneously under field conditions in high-resistivity water, without the need for chemical addition to increase conductivity.

Prediction of failure enthalpy and reliability of irradiated fuel rod under reactivity-initiated accidents by means of statistical approach

International Nuclear Information System (INIS)

Nam, Cheol; Choi, Byeong Kwon; Jeong, Yong Hwan; Jung, Youn Ho

2001-01-01

During the last decade, the failure behavior of high-burnup fuel rods under RIA has been an extensive concern since observations of fuel rod failures at low enthalpy. Of great importance is placed on failure prediction of fuel rod in the point of licensing criteria and safety in extending burnup achievement. To address the issue, a statistics-based methodology is introduced to predict failure probability of irradiated fuel rods. Based on RIA simulation results in literature, a failure enthalpy correlation for irradiated fuel rod is constructed as a function of oxide thickness, fuel burnup, and pulse width. From the failure enthalpy correlation, a single damage parameter, equivalent enthalpy, is defined to reflect the effects of the three primary factors as well as peak fuel enthalpy. Moreover, the failure distribution function with equivalent enthalpy is derived, applying a two-parameter Weibull statistical model. Using these equations, the sensitivity analysis is carried out to estimate the effects of burnup, corrosion, peak fuel enthalpy, pulse width and cladding materials used

Enthalpy of solution of rubidium nitrate in water

International Nuclear Information System (INIS)

Weintraub, R.; Apelblat, A.; Tamir, A.

1984-01-01

Molar enthalpies of solution of RbNO 3 in water at 298.15 K were measured in an LKB calorimeter. The molar enthalpies of solution extrapolated to infinite solution are: (36788 +- 30)J. mol -1 (Alfa) and (36539 +- 52)J.mol -1 (Aldrich). (author)

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.

Vapor pressure and enthalpy of vaporization of linear aliphatic alkanediamines

International Nuclear Information System (INIS)

Pozdeev, Vasiliy A.; Verevkin, Sergey P.

2011-01-01

Highlights: → We measured vapor pressure of diamines H 2 N-(CH 2 ) n -NH 2 with n = 3 to 12. → Vaporization enthalpies at 298 K were derived. → We examined consistency of new and available in the literature data. → Enthalpies of vaporization show linear dependence on numbers n. → Enthalpies of vaporization correlate linearly with Kovat's indices. - Abstract: Vapor pressures and the molar enthalpies of vaporization of the linear aliphatic alkanediamines H 2 N-(CH 2 ) n -NH 2 with n = (3 to 12) have been determined using the transpiration method. A linear correlation of enthalpies of vaporization (at T = 298.15 K) of the alkanediamines with the number n and with the Kovat's indices has been found, proving the internal consistency of the measured data.

[Enthalpy stabilization of chicken egg lysozyme in aqueous dimethylsulfoxide solutions].

Science.gov (United States)

Kovrigin, E L; Kirkitadze, M D; Potekhin, S A

1996-01-01

Scanning microcalorimetry data have been used to plot the dependences of the denaturation enthalpy of hen egg lysozyme on dimethylsulfoxide concentration at fixed temperatures. It has been shown that at dimethylsulfoxide concentrations below 40% (v/v) the enthalpy does not depend on pH of the medium. An increase of dimethylsulfoxide concentrations in this range leads to a linear growth of enthalpy. The rate of enthalpy growth decreases with the temperature increase. The denaturation enthalpy begins to considerably depend on pH at dimethylsulfoxide concentrations more than 40%. Spectroscopy data indicate that conformational changes occur in the protein in this range of concentrations already at room temperature, whereas according to scanning microcalorimetry, they take place at much higher temperatures. This difference is probably due to a decrease of the real temperature of protein melting below room temperature and a very inhibited character of the denaturational transition. This results in a decrease of calorimetric enthalpy at acidic pH owing to incomplete protein renaturation upon calorimeter cooling to the starting point.

Experimental formation enthalpies for intermetallic phases and other inorganic compounds

Science.gov (United States)

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

2017-01-01

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. PMID:29064466

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

Science.gov (United States)

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

2018-03-01

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 Elsevier B.V. All rights reserved.

Standard enthalpies of formation of uranium compounds

International Nuclear Information System (INIS)

Cordfunke, E.H.P.; Ouweltjes, W.

1977-01-01

Enthalpies of solution of β-UO 2 SO 4 and α-UO 2 SeO 4 in H 2 SO 4 (aq) and of UO 2 SeO 3 in H 2 SO 4 (aq) + Ce(SO 4 ) 2 have been measured calorimetrically. Together with measurements of the enthalpy of solution of γ-UO 3 in these solvents, the standard enthalpies of formation of anhydrous β-UO 2 SO 4 , α-UO 2 SeO 4 , and UO 2 SeO 3 have been derived. The results obtained are: ΔHsub(f) 0 (s, 298.15 K)/ kcalsub(th) mol -1 : β-UO 2 SO 4 , -(440.9 +- 0.2); α-UO 2 SeO 4 , -(367.9 +- 0.8); UO 2 SeO 3 , -(363.8 +- 0.2). (author)

Leakage analysis of crossbar memristor arrays

KAUST Repository

Zidan, Mohammed A.; Salem, Ahmed Sultan; Fahmy, Hossam Aly Hassan; Salama, Khaled N.

2014-01-01

the readout operation. In this work we study the trade-off between the crossbar array density and the power consumption required for its readout. Our analysis is based on simulating full memristor arrays on a SPICE platform.

Excess molar enthalpies for binary mixtures of different amines with water

International Nuclear Information System (INIS)

Zhang, Ruilei; Chen, Jian; Mi, Jianguo

2015-01-01

Highlights: • Isothermal excess molar enthalpies for binary mixtures of different amines with water. • The Redlich–Kister equation and the NRTL model was used to fit the experimental data. • The excess molar enthalpies were discussed with different structures of amines. - Abstract: The isothermal excess molar enthalpies for binary mixtures of different amines with water were measured with a C-80 Setaram calorimeter. The experimental results indicate that the excess molar enthalpy is related to the molecular structure. The experimental excess molar enthalpies were satisfactorily fitted with the Redlich–Kister equation. They were also used to test the suitability of the NRTL model, and the deviations are a little larger than the R–K equation

Solar array qualification through qualified analysis

Science.gov (United States)

Zijdemans, J.; Cruijssen, H. J.; Wijker, J. J.

1991-04-01

To achieve qualification is in general a very expensive exercise. For solar arrays this is done by a dedicated test program through which final qualification is achieved. Due to severe competition on the solar array market, cheaper means are looked for to achieve a qualified product for the customers. One of the methods is to drastically limit the environmental test program and to qualify the solar-array structure against its environmental loads by analysis. Qualification by analysis is possible. The benefits are that a significant amount of development effort can be saved in case such a powerful tool is available. Extensive testing can be avoided thus saving time and money.

Immersion enthalpies of activated carbon cloths as physical chemistry characterization parameter

International Nuclear Information System (INIS)

Rodriguez, Giovanny; Giraldo, Liliana; Moreno Juan Carlos

2009-01-01

The immersion enthalpies of five activated carbon cloths in carbon, CCl 4 , H 2 O and NaOH and HCl 0.1 M solutions are determined. The surface area values of the cloths are between 243 and 848 m 2 g-1 and exhibit a linear relationship with the immersion enthalpies in CCl 4 . The immersion enthalpies of carbon cloths are between 5.49 and 42.3 Jg-1 for CCl 4 and 3.83 and 7.54 Jg-1 for H 2 O. The immersion enthalpies in the solutions are related to the contents of acidic and basic groups and find that in the first case to increase the immersion enthalpy in NaOH increases the total acidity. Hydrophobic factor is calculated from the immersion enthalpies in CCl 4 and H 2 O, that indicate the interaction with polar and a polar compounds, and also relates to pHPZC each sample.

The determination of the enthalpy of formation and the enthalpy increment of Cd0.5 Te0.5 by Calvet calorimetry

International Nuclear Information System (INIS)

Agarwal, R.; Venugopal, V.; Sood, D.D.

1993-01-01

In the present study the enthalpy of formation of Cd 0.5 Te 0.5 compound at 785 K were determined from the two elements by direct reaction calorimetry using two different types of set-ups. The enthalpy increment values were measured by drop technique in Calvet calorimetry. (author). 3 refs., 4 tabs

Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds. Sublimation, Vaporization and Fusion Enthalpies From 1880 to 2015. Part 1. C1 - C10

Science.gov (United States)

Acree, William; Chickos, James S.

2016-09-01

A compendium of phase change enthalpies published in 2010 is updated to include the period 1880-2015. Phase change enthalpies including fusion, vaporization, and sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds. Part 1 of this compendium includes organic compounds from C1 to C10. Part 2 of this compendium, to be published separately, will include organic and organometallic compounds from C11 to C192. Sufficient data are presently available to permit thermodynamic cycles to be constructed as an independent means of evaluating the reliability of the data. Temperature adjustments of phase change enthalpies from the temperature of measurement to the standard reference temperature, T = 298.15 K, and a protocol for doing so are briefly discussed.

Application of low enthalpy geothermal energy

International Nuclear Information System (INIS)

Stancher, B.; Giannone, G.

2007-01-01

Geothermal energy comes from the superficial layers of the Earth's crust; it can be exploited in several ways, depending on its temperature. Many systems have been developed to use this clean and renewable energy resource. This paper deals with a particular application of low enthalpy geothermal energy in Latisana (district of Udine NE, Italy). The Latisana's indoor stadium is equipped with geothermal plant that uses low temperature water (29-30 0 ) to provide heating. Economic analysis shows that the cost of its plant is comparable to the cost powered by other kinds of renewable energy resources

Standard molar enthalpies of formation of 1- and 2-cyanonaphthalene

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.; Barros, Ana L.M.; Bessa, Ana R.C.; Brito, Barbara C.S.A.; Vieira, Joana A.S.; Martins, Silvia A.P.

2011-01-01

Highlights: → Enthalpies of formation of 1- and 2-cyanonaphthalene were measured by combustion calorimetry. → Vapor pressures of crystalline 1- and 2-cyanonaphthalene obtained by Knudsen effusion mass loss technique. → Enthalpies, entropies and Gibbs functions of sublimation at T = 298.15 K were calculated. - Abstract: The standard (p o = 0.1 MPa) molar enthalpies of formation, in the crystalline state, of the 1- and 2-cyanonaphthalene were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static-bomb combustion calorimetry. Vapor pressure measurements at different temperatures, using the Knudsen mass loss effusion technique, enabled the determination of the enthalpy, entropy, and Gibbs energy of sublimation, at T = 298.15 K, for both isomers. The standard molar enthalpies of sublimation, at T = 298.15 K, for 1- and 2-cyanonaphthalene, were also measured by high-temperature Calvet microcalorimetry. (table) Combining these two experimental values, the gas-phase standard molar enthalpies, at T = 298.15 K, were derived and compared with those estimated by employing two different methodologies: one based on the Cox scheme and the other one based on G3MP2B3 calculations. The calculated values show a good agreement with the experimental values obtained in this work.

Enthalpies of formation of selected Co{sub 2}YZ Heusler compounds

Energy Technology Data Exchange (ETDEWEB)

Yin, Ming, E-mail: myin1@hawk.iit.edu; Chen, Song; Nash, Philip

2013-11-15

Highlights: •Enthalpies of formation of selected Co{sub 2}YZ were measured by drop calorimeters. •Enthalpy decreases as the Z element approaches the top right corner of the periodic table. •For the Y element, enthalpy increases on increasing the number of d electrons. •Result of L2{sub 1} structured compounds agrees with first principles data. •Lattice parameters and related phase relationships were consistent with literature data. -- Abstract: Standard enthalpies of formation at 298 K of selected ternary Co{sub 2}-based Heusler compounds Co{sub 2}YZ (Y = Fe, Hf, Mn, Ti, V, Zr; Z = Al, Ga, In, Si, Ge, Sn) were measured by high temperature direct synthesis calorimetry. The measured enthalpies of formation (in kJ/mole of atoms) of the L2{sub 1} compounds are: Co{sub 2}FeGa (−25.8 ± 2.6); Co{sub 2}FeSi (−38.4 ± 2.2); Co{sub 2}FeGe (−11.6 ± 2.1); Co{sub 2}MnGa (−30.1 ± 2.3); Co{sub 2}MnSi (−42.4 ± 1.2); Co{sub 2}MnGe (−31.6 ± 3.0); Co{sub 2}MnSn (−15.6 ± 2.8); Co{sub 2}TiAl (−55.0 ± 3.7); Co{sub 2}TiGa (−54.2 ± 2.6); Co{sub 2}TiSi (−61.4 ± 1.7); Co{sub 2}TiGe (−59.3 ± 3.8); Co{sub 2}TiSn (−38.4 ± 2.0); Co{sub 2}VGa (−28.4 ± 1.1) and for the B2 compounds: Co{sub 2}FeAl (−22.5 ± 2.5), Co{sub 2}MnAl (−27.6 ± 2.7). Values are compared with those from first principles calculation when available and the extended semi-empirical model of Miedema. Trends in enthalpy of formation with element atomic number are discussed. Lattice parameters of the compounds with L2{sub 1} structure are determined by X-ray diffraction analysis.

Vapor pressure and enthalpy of vaporization of aliphatic propanediamines

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Chernyak, Yury

2012-01-01

Highlights: ► We measured vapor pressure of four aliphatic 1,3-diamines. ► Vaporization enthalpies at 298 K were derived. ► We examined consistency of new and available data in the literature. ► A group-contribution method for prediction was developed. - Abstract: Vapor pressures of four aliphatic propanediamines including N-methyl-1,3-propanediamine (MPDA), N,N-dimethyl-1,3-propanediamine (DMPDA), N,N-diethyl-1,3-propanediamine (DEPDA) and N,N,N′,N′-tetramethyl-1,3-propanediamine (4MPDA) were measured using the transpiration method. The vapor pressures developed in this work and reported in the literature were used to derive molar enthalpy of vaporization values at the reference temperature 298.15 K. An internal consistency check of the enthalpy of vaporization was performed for the aliphatic propanediamines studied in this work. A group-contribution method was developed for the validation and prediction vaporization enthalpies of amines and diamines.

Hypervelocity Expansion Facility for Fundamental High-Enthalpy Research

Science.gov (United States)

2017-02-27

ii Final Technical Report of Contract ONR N00014-15-1-2260 Entitled: HYPERVELOCITY EXPANSION FACILITY FOR FUNDAMENTAL HIGH-ENTHALPY...previous DoD investments in high-energy pulsed laser diagnostics for instantaneous planar velocimetry and thermometry to perform scientific studies of...capability for fundamental and applied studies of hypervelocity high enthalpy flows. In this document, we report on the progress over the 18-month

The Calculation of Standard Enthalpies of Formation of Alkanes: Illustrating Molecular Mechanics and Spreadsheet Programs

Science.gov (United States)

Hawk, Eric Leigh

1999-02-01

How group increment methods may be used to predict standard enthalpies of formation of alkanes is outlined as an undergraduate computational chemistry experiment. The experiment requires input and output data sets. Although users may create their own data sets, both sets are provided. The input data set contains experimentally determined gas-phase standard enthalpies of formation and calculated steric energies for 10 alkanes. The steric energy for an alkane is calculated via a Molecular Mechanics approach employing Allinger's MM3 force field. Linear regression analysis on data contained in the input data set generates the coefficients that are used with the output data set to calculate standard enthalpies of formation for 15 alkanes. The average absolute error for the calculated standard enthalpies of formation is 1.22 kcal/mol. The experiment is highly suited to those interested in incorporating more computational chemistry in their curricula. In this regard, it is ideally suited for a physical chemistry laboratory, but it may be used in an organic chemistry course as well.

Update-in-Place Analysis for True Multidimensional Arrays

Directory of Open Access Journals (Sweden)

Steven M. Fitzgerald

1996-01-01

Full Text Available Applicative languages have been proposed for defining algorithms for parallel architectures because they are implicitly parallel and lack side effects. However, straightforward implementations of applicative-language compilers may induce large amounts of copying to preserve program semantics. The unnecessary copying of data can increase both the execution time and the memory requirements of an application. To eliminate the unnecessary copying of data, the Sisal compiler uses both build-in-place and update-in-place analyses. These optimizations remove unnecessary array copy operations through compile-time analysis. Both build-in-place and update-in-place are based on hierarchical ragged arrays, i.e., the vector-of-vectors array model. Although this array model is convenient for certain applications, many optimizations are precluded, e.g., vectorization. To compensate for this deficiency, new languages, such as Sisal 2.0, have extended array models that allow for both high-level array operations to be performed and efficient implementations to be devised. In this article, we introduce a new method to perform update-in-place analysis that is applicable to arrays stored either in hierarchical or in contiguous storage. Consequently, the array model that is appropriate for an application can be selected without the loss of performance. Moreover, our analysis is more amenable for distributed memory and large software systems.

Standard enthalpies of formation of selected Rh2YZ Heusler compounds

International Nuclear Information System (INIS)

Yin, Ming; Nash, Philip

2015-01-01

The standard enthalpies of formation (Δ f H°) of selected ternary Rh-based Rh 2 YZ (Y = Cu, Fe, Mn, Ni, Ru, Ti, V; Z = Al, Ga, In, Si, Ge, Sn) compounds were measured using high temperature direct reaction calorimetry. The measured standard enthalpies of formation (in kJ/mol of atoms) are, for the Heusler compound Rh 2 MnSn (−40.1 ± 3.6), for the B2-structured compounds: Rh 2 FeAl (−48.5 ± 2.9); Rh 2 MnAl (−72.4 ± 2.7); Rh 2 MnGa (−55.3 ± 2.0); Rh 2 MnIn (−35.3 ± 1.9), for the tetragonal compounds: Rh 2 FeSn (−28.9 ± 1.3); Rh 2 TiAl (−97.6 ± 2.2); Rh 2 TiGa (−79.0 ± 1.8); Rh 2 TiSn (−74.7 ± 3.1). Values are compared with those from first principles calculations in published papers and the Open Quantum Materials Database (OQMD). Lattice parameters of these compounds are determined using X-ray diffraction analysis (XRD). Microstructures were characterized using scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). - Highlights: • Standard enthalpies of formation of Rh 2 YZ were measured using a drop calorimeter. • Measured enthalpies agree with first principles data in general. • Lattice parameters and related phase relationships were consistent with literature data. • Rh 2 TiSn of tI8 structure were reported for the first time.

Determination of vaporization enthalpies of polychlorinated biphenyls by correlation gas chromatography.

Science.gov (United States)

Puri, S; Chickos, J S; Welsh, W J

2001-04-01

The vaporization enthalpies of 16 polychlorinated biphenyls have been determined by correlation gas chromatography. This study was prompted by the realization that the vaporization enthalpy of the standard compounds used in previous studies, octadecane and eicosane, were values measured at 340 and 362 K, respectively, rather than at 298 K. Adjustment to 298 K amounts to a 7-8 kJ/mol increment in the values. With the inclusion of this adjustment, vaporization enthalpies evaluated by correlation gas chromatography are in good agreement with the values determined previously in the literature. The present results are based on the vaporization enthalpies of several standards whose values are well established in the literature. The standards include a variety of n-alkanes and various chlorinated hydrocarbons. The vaporization enthalpies of PCBs increased with the number of chlorine atoms and were found to be larger for meta- and para-substituted polychlorinated biphenyls.

Hybrid Information Flow Analysis for Programs with Arrays

Directory of Open Access Journals (Sweden)

Gergö Barany

2016-07-01

Full Text Available Information flow analysis checks whether certain pieces of (confidential data may affect the results of computations in unwanted ways and thus leak information. Dynamic information flow analysis adds instrumentation code to the target software to track flows at run time and raise alarms if a flow policy is violated; hybrid analyses combine this with preliminary static analysis. Using a subset of C as the target language, we extend previous work on hybrid information flow analysis that handled pointers to scalars. Our extended formulation handles arrays, pointers to array elements, and pointer arithmetic. Information flow through arrays of pointers is tracked precisely while arrays of non-pointer types are summarized efficiently. A prototype of our approach is implemented using the Frama-C program analysis and transformation framework. Work on a full machine-checked proof of the correctness of our approach using Isabelle/HOL is well underway; we present the existing parts and sketch the rest of the correctness argument.

Fault Analysis in Solar Photovoltaic Arrays

Science.gov (United States)

Zhao, Ye

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays. First, this thesis introduces new simulation and analytic models that are suitable for fault analysis in PV arrays. Based on the simulation environment, this thesis studies a variety of typical faults in PV arrays, such as ground faults, line-line faults, and mismatch faults. The effect of a maximum power point tracker on fault current is discussed and shown to, at times, prevent the fault current protection devices to trip. A small-scale experimental PV benchmark system has been developed in Northeastern University to further validate the simulation conclusions. Additionally, this thesis examines two types of unique faults found in a PV array that have not been studied in the literature. One is a fault that occurs under low irradiance condition. The other is a fault evolution in a PV array during night-to-day transition. Our simulation and experimental results show that overcurrent protection devices are unable to clear the fault under "low irradiance" and "night-to-day transition". However, the overcurrent protection devices may work properly when the same PV fault occurs in daylight. As a result, a fault under "low irradiance" and "night-to-day transition" might be hidden in the PV array and become a potential hazard for system efficiency and reliability.

Integral enthalpy of mixing of the liquid ternary Au-Cu-Sn system

International Nuclear Information System (INIS)

Knott, S.; Li, Z.; Mikula, A.

2008-01-01

The integral enthalpy of mixing of the ternary Au-Cu-Sn has been determined with a Calvet type calorimeter at 6 different cross sections at 1273 K. The substitutional solution model of Redlich-Kister-Muggianu was used for a least square fit of the experimental data in order to get an analytical expression for the integral enthalpy of mixing. The ternary extrapolation models of Kohler, Muggianu and Toop were used to calculate the integral enthalpy of mixing and to compare measured and extrapolated values. Additional calculations of the integral enthalpy of mixing using the Chou model have been performed. With the calculated data, the iso-enthalpy lines have been determined using the Redlich-Kister-Muggianu model. A comparison of the data has been made

arrayCGHbase: an analysis platform for comparative genomic hybridization microarrays

Directory of Open Access Journals (Sweden)

Moreau Yves

2005-05-01

Full Text Available Abstract Background The availability of the human genome sequence as well as the large number of physically accessible oligonucleotides, cDNA, and BAC clones across the entire genome has triggered and accelerated the use of several platforms for analysis of DNA copy number changes, amongst others microarray comparative genomic hybridization (arrayCGH. One of the challenges inherent to this new technology is the management and analysis of large numbers of data points generated in each individual experiment. Results We have developed arrayCGHbase, a comprehensive analysis platform for arrayCGH experiments consisting of a MIAME (Minimal Information About a Microarray Experiment supportive database using MySQL underlying a data mining web tool, to store, analyze, interpret, compare, and visualize arrayCGH results in a uniform and user-friendly format. Following its flexible design, arrayCGHbase is compatible with all existing and forthcoming arrayCGH platforms. Data can be exported in a multitude of formats, including BED files to map copy number information on the genome using the Ensembl or UCSC genome browser. Conclusion ArrayCGHbase is a web based and platform independent arrayCGH data analysis tool, that allows users to access the analysis suite through the internet or a local intranet after installation on a private server. ArrayCGHbase is available at http://medgen.ugent.be/arrayCGHbase/.

Performance Analysis of Digital loudspeaker Arrays

DEFF Research Database (Denmark)

Pedersen, Bo Rohde; Kontomichos, Fotios; Mourjopoulos, John

2008-01-01

An analysis of digital loudspeaker arrays shows that the ways in which bits are mapped to the drivers influence the quality of the audio result. Specifically, a "bit-summed" rather than the traditional "bit-mapped" strategy greatly reduces the number of times drivers make binary transitions per...... period of the input frequency. Detailed simulations compare the results for a 32-loudspeaker array with a similar configuration with analog excitation of the drivers. Ideally, drivers in digital arrays should be very small and span a small area, but that sets limits on the low-frequency response...

Enthalpy of Formation of N2H4 (Hydrazine) Revisited.

Science.gov (United States)

Feller, David; Bross, David H; Ruscic, Branko

2017-08-17

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 (97.42 ± 0.47 kJ/mol at 298.15 K). Close agreement was found between the ATcT (even excluding the latest theoretical result) and the FPD enthalpy.

Formation enthalpy of iron, chromium and aluminium vanadates

International Nuclear Information System (INIS)

Kesler, Ya.A.; Cheshnitskij, S.M.; Fotiev, A.A.; Tret'yakov, Yu.D.

1985-01-01

The enthalpies of formation of FeVO 4 , CrVO 4 and AlVO 4 orthovanadates are determined. The method for measuring reaction heats of direct synthesis of oxide compounds is used. All experiments have been conducted at 973 K. The measurements have been performed by the drop-calorimetry method using high temperature differential microcalorimeter. The specified enthalpy values of FeVO 4 , CrVO 4 , AlVO 4 and FeCr(VO 4 ) 2 formation are obtained

Predicting the enthalpies of melting and vaporization for pure components

Science.gov (United States)

Esina, Z. N.; Korchuganova, M. R.

2014-12-01

A mathematical model of the melting and vaporization enthalpies of organic components based on the theory of thermodynamic similarity is proposed. In this empirical model, the phase transition enthalpy for the homological series of n-alkanes, carboxylic acids, n-alcohols, glycols, and glycol ethers is presented as a function of the molecular mass, the number of carbon atoms in a molecule, and the normal transition temperature. The model also uses a critical or triple point temperature. It is shown that the results from predicting the melting and vaporization enthalpies enable the calculation of binary phase diagrams.

Standard molar enthalpies of formation and of sublimation of the terphenyl isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Lima, Luis M. Spencer S.

2008-01-01

The standard (p 0 = 0.1 MPa) molar enthalpies of formation in the crystalline phases of ortho, meta and para-terphenyl isomers, at T = 298.15 K, were derived from the standard molar energies of combustion, measured by mini-bomb combustion calorimetry. The Knudsen mass-loss effusion technique was used to measure the dependence of the vapour pressure of the crystals with the temperature, thus deriving their standard molar enthalpies of sublimation by means of the Clausius-Clapeyron equation. Combining the standard molar enthalpies of formation and sublimation of the crystalline terphenyls, the standard molar enthalpies of formation in the gaseous state, at T = 298.15 K, were derived for the three isomers. Results are provided in a table. The results show small but detectable isomerization enthalpies between the terphenyls, indicating the following relative enthalpic stabilities: m- > p- ∼ o-terphenyl

Standard molar enthalpies of formation of three N-benzoylthiocarbamic-O-alkylesters

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.; Schroeder, Bernd; Dietze, Frank; Beyer, Lothar

2004-01-01

The standard (p 0 =0.1 MPa) molar enthalpies of combustion in oxygen of three crystalline N-benzoylthiocarbamic-O-alkylesters, PhCONHCSOR, R=Et (Hbtcee), n-Bu (Hbtcbe), n-Hex (Hbtche), were measured at T=298.15 K by rotating bomb calorimetry. The standard molar enthalpies of sublimation of the three compounds were measured using Calvet microcalorimetry. These values were used to derive the standard molar enthalpies of formation of the compounds in their crystalline and gaseous phases, respectively

Enthalpies of vaporization of some acetylene peroxy derivatives of carboranes-12

International Nuclear Information System (INIS)

Dibrivnyj, V.N.; Pistun, Z.E.; Van-Chin-Syan, Yu.Ya.; Yuvchenko, A.P.; Zvereva, T.D.

1999-01-01

Temperature dependences of saturated vapor pressure and vaporization enthalpies of five acetylene peroxy derivatives of carboranes-12 are determined by the Knudsen effusion method. Enthalpies and melting points of crystals, as well as temperatures of liquid compounds decomposition start are determined by the method of differential scanning calorimetry. Comparison of evaporation enthalpies determined in the study confirms the conclusions on non-additive character of intermolecular interaction in carboranes and their derivatives, which have been made previously [ru

Balanced into array : genome-wide array analysis in 54 patients with an apparently balanced de novo chromosome rearrangement and a meta-analysis

NARCIS (Netherlands)

Feenstra, Ilse; Hanemaaijer, Nicolien; Sikkema-Raddatz, Birgit; Yntema, Helger; Dijkhuizen, Trijnie; Lugtenberg, Dorien; Verheij, Joke; Green, Andrew; Hordijk, Roel; Reardon, William; de Vries, Bert; Brunner, Han; Bongers, Ernie; de Leeuw, Nicole; van Ravenswaaij-Arts, Conny

2011-01-01

High-resolution genome-wide array analysis enables detailed screening for cryptic and submicroscopic imbalances of microscopically balanced de novo rearrangements in patients with developmental delay and/or congenital abnormalities. In this report, we added the results of genome-wide array analysis

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

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.; Boaventura, Cristina R.P.; Gomes, Jose R.B.

2008-01-01

The standard (p 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 -1 , -(153.6 ± 1.7) kJ . mol -1 and -(157.1 ± 1.4) kJ . mol -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

Enthalpy changes when passing from simple to complex perovskite-like oxides

International Nuclear Information System (INIS)

Reznitskij, L.A.

1999-01-01

Formation enthalpies of complex perovskite-like oxides and their hexagonal analogs of the composition: Ba 2 ReFeO 6 , Sr 2 ReFeO 6 , Sr 2 ReMnO 6 , Ca 2 ReMnO 6 , Sr 2 WCrO 6 , Sr 2 MoCrO 6 , Ca 2 MoCrO 6 , Ca 2 WCrO 6 , Ba 3 Fe 2 ReO 9 , Ba 3 Cr 2 ReO 9 , Ba 2 RhTaO 6 and B 2 ScIrO 6 from simple oxides were calculated by approximate method using enthalpies of the cations coordination change in oxygen medium. The conclusion was made that enthalpy stabilization of the oxide with regard to simple oxides is mainly determined by the change in enthalpies of alkaline earth metal cations [ru

Status on high enthalpy geothermal resources in Greece

International Nuclear Information System (INIS)

Koutinas, G.A.

1990-01-01

Greece is privileged to have many high and medium enthalpy geothermal resources. Related activities during the last 5 years were conducted mainly on the previously discovered geothermal fields of Milos, Nisyros and Lesvos islands, without any deep geothermal drilling. Most efforts were focused on the demonstration of a high enthalpy geothermal reservoir on Milos, by generating electricity from high salinity fluid, with a 2 MW pilot plant. Significant experience has been gained there, by solving technical problems, but still site specific constraints have to be overcome in order to arrive at a comprehensive feasibility study, leading to the development phase. A pre-feasibility study has been carried out in the Nisyros geothermal field. Moreover, a detailed geoscientific exploration program has been completed on Lesvos island, where very promising geothermal areas have been identified. In this paper, reference is made to the most important data concerning high enthalpy geothermal resources by emphasizing the Milos geothermal field

A combined experimental and computational investigation of excess molar enthalpies of (nitrobenzene + alkanol) mixtures

International Nuclear Information System (INIS)

Neyband, Razieh Sadat; Zarei, Hosseinali

2015-01-01

Highlights: • Excess molar enthalpies for the binary mixtures of nitrobenzene + alkanols mixtures were measured. • The infinite dilution excess partial molar enthalpies were calculated using the ab initio methods. • The PCM calculations were performed. • The computed excess partial molar enthalpies at infinite dilution were compared to experimental results. - Abstract: Excess molar enthalpies (H m E ) for the binary mixtures of {(nitrobenzene + ethanol), 1-propanol, 2-propanol, 1-butanol and 2-butanol} have been measured over the entire composition range at ambient pressure (81.5 kPa) and temperature 298 K using a Parr 1455 solution calorimeter. From the experimental results, the excess partial molar enthalpies (H i E ) and excess partial molar enthalpies at infinite dilution (H i E,∞ ) were calculated. The excess molar enthalpies (H m E ) are positive for all {nitrobenzene (1) + alkanol (2)} mixtures over the entire composition range. A state-of-the-art computational strategy for the evaluation of excess partial molar enthalpies at infinite dilution was followed at the M05-2X/6-311++G ∗∗ level of theory with the PCM model. The experimental excess partial molar enthalpies at infinite dilution have been compared to the computational data of the ab initio in liquid phase. Integrated experimental and computational results help to clarify the nature of the intermolecular interactions in {nitrobenzene (1) + alkanol (2)} mixtures. The experimental and computational work which was done in this study complements and extends the general research on the computation of excess partial molar enthalpy at infinite dilution of binary mixtures

Waveguide Phased Array Antenna Analysis and Synthesis

NARCIS (Netherlands)

Visser, H.J.; Keizer, W.P.M.N.

1996-01-01

Results of two software packages for analysis and synthesis of waveguide phased array antennas are shown. The antennas consist of arrays of open-ended waveguides where irises can be placed in the waveguide apertures and multiple dielectric sheets in front of the apertures in order to accomplish a

Enthalpy of formation of titanium diboride

International Nuclear Information System (INIS)

Akhachinskij, V.V.; Chirin, N.A.

1975-01-01

The values given in the literature for the enthalpy of the formation of titanium diboride, as obtained experimentally and by theoretical estimation, range between -32 and -74.4 kcal/mol. In this paper the authors use the method of direct synthesis from elements in a Calvet calorimeter to determine the enthalpy of formation, ΔHsub(f) 0 , sub(298), of titanium diboride with the composition Tisub(1.000+-0.002)Bsub(2.056+-0.006)Csub(0.009)Nsub(0.003), which was found to be -76.78+-0.83 kcal/mol. They calculate that ΔHsub(f,298) (TiBsub(2.056)=-76.14+-0.85 kcal/mol. The procedure employed makes it possible to carry out the titanium diboride synthesis reaction with the calorimeter at room temperature

Formation enthalpy of iron, chromium and aluminium vanadates

Energy Technology Data Exchange (ETDEWEB)

Kesler, Ya.A.; Cheshnitskij, S.M.; Fotiev, A.A.; Tret' yakov, Yu.D.

1985-04-01

The enthalpies of formation of FeVO/sub 4/, CrVO/sub 4/ and AlVO/sub 4/ orthovanadates are determined. The method for measuring reaction heats of direct synthesis of oxide compounds is used. All experiments have been conducted at 973 K. The measurements have been performed by the drop-calorimetry method using high temperature differential microcalorimeter. The specified enthalpy values of FeVO/sub 4/, CrVO/sub 4/, AlVO/sub 4/ and FeCr(VO/sub 4/)/sub 2/ formation are obtained.

What is the enthalpy of formation of pyrazine-2-carboxylic acid?

International Nuclear Information System (INIS)

Miranda, Margarida S.; Duarte, Darío J.R.; Liebman, Joel F.

2016-01-01

There are two contemporary conflicting, indeed, incompatible determinations of measurements of the enthalpies of combustion and of formation of pyrazine-2-carboxylic acid in the literature, (−2268.0 ± 0.9 and −271.2 ± 1.1 kJ · mol −1 ) and (−2211.4 ± 0.9 and −327.8 ± 1.1 kJ · mol −1 ). The current paper discusses these two sets of values and from the use of a measurement of the enthalpy of sublimation, a newly evaluated enthalpy of formation of pyrazine itself, and of the quantum chemical calculations at the G3(MP2)//B3LYP level, the former results are accepted and the derived gas phase enthalpy of formation, −(167.6 ± 3.1) kJ · mol −1 , suggested.

Improved algorithm based on equivalent enthalpy drop method of pressurized water reactor nuclear steam turbine

International Nuclear Information System (INIS)

Wang Hu; Qi Guangcai; Li Shaohua; Li Changjian

2011-01-01

Because it is difficulty to accurately determine the extraction steam turbine enthalpy and the exhaust enthalpy, the calculated result from the conventional equivalent enthalpy drop method of PWR nuclear steam turbine is not accurate. This paper presents the improved algorithm on the equivalent enthalpy drop method of PWR nuclear steam turbine to solve this problem and takes the secondary circuit thermal system calculation of 1000 MW PWR as an example. The results show that, comparing with the design value, the error of actual thermal efficiency of the steam turbine cycle obtained by the improved algorithm is within the allowable range. Since the improved method is based on the isentropic expansion process, the extraction steam turbine enthalpy and the exhaust enthalpy can be determined accurately, which is more reasonable and accurate compared to the traditional equivalent enthalpy drop method. (authors)

Enthalpy measurement of lithium meta-titanate by drop calorimetry and its derived heat capacity

International Nuclear Information System (INIS)

Ishioka, Rika; Mukai, Keisuke; Terai, Takayuki; Suzuki, Akihiro

2013-01-01

Highlights: • Li 2 TiO 3 was synthesized by a neutralizing method. • Enthalpy of Li 2 TiO 3 was measured by a drop calorimeter. • Heat capacity of Li 2 TiO 3 was derived as a function of temperature. -- Abstract: Enthalpy of Li 2 TiO 3 , which was synthesized by a neutralizing method and its Li/Ti ratio was determined to be Li/Ti ratio (mol/mol) = 1.97, was measured by a drop calorimeter, and its heat capacity was derived as a function of temperature. XRD (X-ray diffraction) analysis of the sample before and after the enthalpy measurement indicated no phase change during the measurement and a single phase of Li 2 TiO 3 was observed. The enthalpy data were expressed as H(T) − H(323.17) (J/g) = 2.2 × 10 −5 ·T 2 + 1.4·T + 2.7 × 10 4 /T − 5.6 × 10 2 (373–1273 K), where T is temperature in K. The heat capacity was calculated as C p (J/g K) = 2.2 × 2 × 10 −5 ·T + 1.4–2.7 × 10 4 /T 2 by differentiating the equation by temperature. These equations have accuracy of 3%

Enthalpy of Vaporization by Gas Chromatography: A Physical Chemistry Experiment

Science.gov (United States)

Ellison, Herbert R.

2005-01-01

An experiment is conducted to measure the enthalpy of vaporization of volatile compounds like methylene chloride, carbon tetrachloride, and others by using gas chromatography. This physical property was measured using a very tiny quantity of sample revealing that it is possible to measure the enthalpies of two or more compounds at the same time.

Aerosol volatility and enthalpy of sublimation of carboxylic acids.

Science.gov (United States)

Salo, Kent; Jonsson, Asa M; Andersson, Patrik U; Hallquist, Mattias

2010-04-08

The enthalpy of sublimation has been determined for nine carboxylic acids, two cyclic (pinonic and pinic acid) and seven straight-chain dicarboxylic acids (C(4) to C(10)). The enthalpy of sublimation was determined from volatility measurements of nano aerosol particles using a volatility tandem differential mobility analyzer (VTDMA) set-up. Compared to the previous use of a VTDMA, this novel method gives enthalpy of sublimation determined over an extended temperature range (DeltaT approximately 40 K). The determined enthalpy of sublimation for the straight-chain dicarboxylic acids ranged from 96 to 161 kJ mol(-1), and the calculated vapor pressures at 298 K are in the range of 10(-6)-10(-3) Pa. These values indicate that dicarboxylic acids can take part in gas-to-particle partitioning at ambient conditions and may contribute to atmospheric nucleation, even though homogeneous nucleation is unlikely. To obtain consistent results, some experimental complications in producing nanosized crystalline aerosol particles were addressed. It was demonstrated that pinonic acid "used as received" needed a further purification step before being suspended as a nanoparticle aerosol. Furthermore, it was noted from distinct differences in thermal properties that aerosols generated from pimelic acid solutions gave two types of particles. These two types were attributed to crystalline and amorphous configurations, and based on measured thermal properties, the enthalpy of vaporization was 127 kJ mol(-1) and that of sublimation was 161 kJ mol(-1). This paper describes a new method that is complementary to other similar methods and provides an extension of existing experimental data on physical properties of atmospherically relevant compounds.

Vapour pressure and enthalpy of vaporization of aliphatic poly-amines

International Nuclear Information System (INIS)

Efimova, Anastasia A.; Emel'yanenko, Vladimir N.; Verevkin, Sergey P.; Chernyak, Yury

2010-01-01

Molar enthalpies of vaporization of aliphatic poly-amines: 1,4-dimethylpiperazine [106-58-1], 1-(2-aminoethyl)-piperazine, [140-31-8], 1-(2-aminoethyl)-4-methyl-piperazine [934-98-5], and triethylenetetramine [112-24-3] were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. A large number of the primary experimental results on temperature dependences of vapour pressures of the parent compounds have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies of poly-amines at the reference temperature 298.15 K. An internal consistency check was performed on enthalpy of vaporization values for poly-amines studied in this work.

The excess enthalpies of liquid Ge-Pb-Te alloys

International Nuclear Information System (INIS)

Blachnik, R.; Binder, J.; Schlieper, A.

1997-01-01

The excess enthalpies of liquid alloys in the ternary system Ge-Pb-Te were determined at 1210 K in a heat flow calorimeter for five sections Ge y Pb 1-y -Te with y = 0.2, 0.4, 0.5, 0.6 and 0.8 and at 1153 K for Ge 0.5 Pb 0.5 -Te. The enthalpy surface in the ternary system is determined by a valley of exothermic minima, stretching from an exothermic minimum at the composition GeTe to one at the composition PbTe in the respective binaries. The excess enthalpies in the limiting metallic binary were adapted with the Redlich-Kister formalism. For the description of the thermodynamic functions in the ternary system the equation of Bonnier was taken using ternary coefficients. The calculated curves are in good agreement with the experimental data. (orig.)

Standard enthalpies of formation of selected Rh{sub 2}YZ Heusler compounds

Energy Technology Data Exchange (ETDEWEB)

Yin, Ming, E-mail: myin1@hawk.iit.edu; Nash, Philip

2015-11-25

The standard enthalpies of formation (Δ{sub f}H°) of selected ternary Rh-based Rh{sub 2}YZ (Y = Cu, Fe, Mn, Ni, Ru, Ti, V; Z = Al, Ga, In, Si, Ge, Sn) compounds were measured using high temperature direct reaction calorimetry. The measured standard enthalpies of formation (in kJ/mol of atoms) are, for the Heusler compound Rh{sub 2}MnSn (−40.1 ± 3.6), for the B2-structured compounds: Rh{sub 2}FeAl (−48.5 ± 2.9); Rh{sub 2}MnAl (−72.4 ± 2.7); Rh{sub 2}MnGa (−55.3 ± 2.0); Rh{sub 2}MnIn (−35.3 ± 1.9), for the tetragonal compounds: Rh{sub 2}FeSn (−28.9 ± 1.3); Rh{sub 2}TiAl (−97.6 ± 2.2); Rh{sub 2}TiGa (−79.0 ± 1.8); Rh{sub 2}TiSn (−74.7 ± 3.1). Values are compared with those from first principles calculations in published papers and the Open Quantum Materials Database (OQMD). Lattice parameters of these compounds are determined using X-ray diffraction analysis (XRD). Microstructures were characterized using scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). - Highlights: • Standard enthalpies of formation of Rh{sub 2}YZ were measured using a drop calorimeter. • Measured enthalpies agree with first principles data in general. • Lattice parameters and related phase relationships were consistent with literature data. • Rh{sub 2}TiSn of tI8 structure were reported for the first time.

Enthalpy of sublimation/vaporization of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine

International Nuclear Information System (INIS)

Tome, Luciana I.N.; Rosado, Mario T.S.; Nunes, Sandra C.C.; Maria, Teresa M.R.; Canotilho, Joao; Eusebio, M. Ermelinda S.

2007-01-01

The molar enthalpy of sublimation, Δ cr g H m 0 , of trans-cyclohexyl-1,4-diamine and the molar enthalpy of vaporization, Δ l g H m 0 , of cis-cyclohexyl-1,2-diamine, at the temperature 298.15 K, were determined by calorimetry. Δ cr g H m 0 (T=298.15K)=(105.0±0.8)kJ.mol -1 was obtained for the trans-isomer and Δ l g H m 0 (T=298.15K)=(62.2±1.0)kJ.mol -1 for the cis form. The molar enthalpy of fusion of the first compound, at T = 342.1 K, was determined by differential scanning calorimetry. The molar enthalpy of vaporization of the 1,4-isomer was estimated by combining the value of the enthalpy of sublimation with that of the enthalpy of fusion. The values obtained for molar standard enthalpy of vaporization and those available for the enthalpy of the diamines in the gas state were used to calculate the difference between the enthalpies of both compounds in the liquid state

Enthalpy estimation for thermal comfort and energy saving in air conditioning system

International Nuclear Information System (INIS)

Chu, C.-M.; Jong, T.-L.

2008-01-01

The thermal comfort control of a room must consider not only the thermal comfort level but also energy saving. This paper proposes an enthalpy estimation that is conducive for thermal comfort control and energy saving. The least enthalpy estimator (LEE) combines the concept of human thermal comfort with the theory of enthalpy to predict the load for a suitable setting pair in order to maintain more precisely the thermal comfort level and save energy in the air conditioning system

Enthalpy of formation of zircon

International Nuclear Information System (INIS)

Ellison, A.J.G.; Navrotsky, A.

1992-01-01

Using high-temperature solution calorimetry in molt 2PbO · B 2 O 3 , the enthalpy of reaction of the formation of zircon, ZrSiO 4 , from its constituent oxides has been determined: Δ 4 H 977 (ZrSiO 4 ) = -27.9 (±1.9) kJ/mol. With previously reported data for the heat contents of ZrO 2 SiO 2 and ZrSiO 4 and standard-state enthalpies of formation of ZrO 2 and SiO 2 , we obtain Δ f H 298 degrees. (ZrSiO 4 ) = -2034.2 (±3.1) kJ/mol and Δ t G 298 degrees (ZrSiO 4 ) = -1919.8 kJ/mol. The free energy value is in excellent agreement with a range previously estimated from solid-state reaction equilibria. At higher temperature also the data are in close agreement with existing data, though the data sets diverge somewhat with increasing T. In this paper the limitations of the data for predicting the breakdown temperature of zircon into its constituent oxides are discussed

Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

Science.gov (United States)

Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

2012-04-12

Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

R13B1 and R114 exergy-enthalpy charts and their usefulness in a refrigerating-heating process analysis

International Nuclear Information System (INIS)

de Rossi, F.; Mastrullo, R.; Sasso, M.; Sibilio, S.

1989-01-01

R13B1 and R114 exergy-enthalpy diagrams in SI units based on data and equations published by the International Institute of Refrigeration are presented. The charts cover the ranges of 0.5 kPa to 15000 kPa and 120 degrees C to 180 degrees C for R13B1 and 0.8 kPa to 5000 kPa and -70 degrees C to 250 degrees C for R114. In this paper an analysis of a cascade refrigerating-heating compound system is included to illustrate the use of the charts

Standard molar enthalpies of formation of three methyl-pyrazole derivatives

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Cabral, Joana I.T.A.

2012-01-01

Highlights: ► Combustion calorimetry was used to determine Δ f H m ∘ (cr) of methyl-pyrazole derivatives. ► Vapour pressures were determined by the Knudsen mass-loss effusion technique. ► Gas-phase Δ f H m ∘ of the studied compounds have been derived. - Abstract: The standard (p ° = 0.1 MPa) molar enthalpies of formation of the crystalline 3-methyl-1-pyrazolecarboxamide; 3-methyl-3-pyrazoline-5-one; and 4-methyl-2-pyrazoline-5-one were derived from the standard massic energies of combustion, in oxygen, to yield CO 2 (g), H 2 O (l) and N 2 (g), at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpies of sublimation were calculated from the variation of the vapour pressures of each compound with temperature, measured by the Knudsen effusion technique. These two thermodynamic parameters yielded the standard molar enthalpies of formation of the pyrazole derivatives, in the gaseous phase, at T = 298.15 K. The derived standard molar enthalpies of formation, in gaseous state, are analyzed in terms of enthalpic increments and interpreted in terms of molecular structure.

Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11-C192

Science.gov (United States)

Acree, William; Chickos, James S.

2017-03-01

The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11-C192 reported over the period 1880-2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid-solid transitions or behave anisotropically in the liquid state.

High-resolution SNP array analysis of patients with developmental disorder and normal array CGH results

Directory of Open Access Journals (Sweden)

Siggberg Linda

2012-09-01

Full Text Available Abstract Background Diagnostic analysis of patients with developmental disorders has improved over recent years largely due to the use of microarray technology. Array methods that facilitate copy number analysis have enabled the diagnosis of up to 20% more patients with previously normal karyotyping results. A substantial number of patients remain undiagnosed, however. Methods and Results Using the Genome-Wide Human SNP array 6.0, we analyzed 35 patients with a developmental disorder of unknown cause and normal array comparative genomic hybridization (array CGH results, in order to characterize previously undefined genomic aberrations. We detected no seemingly pathogenic copy number aberrations. Most of the vast amount of data produced by the array was polymorphic and non-informative. Filtering of this data, based on copy number variant (CNV population frequencies as well as phenotypically relevant genes, enabled pinpointing regions of allelic homozygosity that included candidate genes correlating to the phenotypic features in four patients, but results could not be confirmed. Conclusions In this study, the use of an ultra high-resolution SNP array did not contribute to further diagnose patients with developmental disorders of unknown cause. The statistical power of these results is limited by the small size of the patient cohort, and interpretation of these negative results can only be applied to the patients studied here. We present the results of our study and the recurrence of clustered allelic homozygosity present in this material, as detected by the SNP 6.0 array.

HTGR core seismic analysis using an array processor

International Nuclear Information System (INIS)

Shatoff, H.; Charman, C.M.

1983-01-01

A Floating Point Systems array processor performs nonlinear dynamic analysis of the high-temperature gas-cooled reactor (HTGR) core with significant time and cost savings. The graphite HTGR core consists of approximately 8000 blocks of various shapes which are subject to motion and impact during a seismic event. Two-dimensional computer programs (CRUNCH2D, MCOCO) can perform explicit step-by-step dynamic analyses of up to 600 blocks for time-history motions. However, use of two-dimensional codes was limited by the large cost and run times required. Three-dimensional analysis of the entire core, or even a large part of it, had been considered totally impractical. Because of the needs of the HTGR core seismic program, a Floating Point Systems array processor was used to enhance computer performance of the two-dimensional core seismic computer programs, MCOCO and CRUNCH2D. This effort began by converting the computational algorithms used in the codes to a form which takes maximum advantage of the parallel and pipeline processors offered by the architecture of the Floating Point Systems array processor. The subsequent conversion of the vectorized FORTRAN coding to the array processor required a significant programming effort to make the system work on the General Atomic (GA) UNIVAC 1100/82 host. These efforts were quite rewarding, however, since the cost of running the codes has been reduced approximately 50-fold and the time threefold. The core seismic analysis with large two-dimensional models has now become routine and extension to three-dimensional analysis is feasible. These codes simulate the one-fifth-scale full-array HTGR core model. This paper compares the analysis with the test results for sine-sweep motion

Specification and comparative calculation of enthalpies and Gibbs formation energies of anhydrous lanthanide nitrates

International Nuclear Information System (INIS)

Del' Pino, Kh.; Chukurov, P.M.; Drakin, S.I.

1980-01-01

Analyzed are the results of experimental depermination of formation enthalpies of waterless nitrates of lanthane cerium, praseodymium, neodymium and samarium. Using method of comparative calculation computed are enthalpies of formation of waterless lanthanide and yttrium nitrates. Calculated values of enthalpies and Gibbs energies of waterless lanthanide nitrate formation are tabulated

Effects of electric fields in polymerization on enthalpy of PMAA anhydridization

Energy Technology Data Exchange (ETDEWEB)

Chang Zhenqi; Liu Gang; Zhang Zhicheng

2004-02-19

PMAA (polymethacrylic acid) polymerized by {gamma}-irradiation in electric field forms six-membered cyclic anhydride during heating process and the enthalpy of PMAA anhydridization was determined by DSC. Why the endothermic peak of PMAA anhydridization in DSC curve between 200 and 300 deg. C appears is particularly explained by calculation. The relations between applied electric field and the enthalpy of PMAA anhydridization are studied. The results show that, with the increases of the intensity of electric field in polymerization, the enthalpy of PMAA forming anhydrides nonlinearly increase, which might be related to orientation of carboxylic acid groups of the PMAA in an electric field.

Standard molar enthalpies of formation of 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.

2009-01-01

The standard (p 0 = 0.1 MPa) molar energies of combustion of 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde were measured by static bomb combustion calorimetry; the Calvet high-temperature microcalorimetry was used to measure the enthalpies of vaporization of these liquid compounds. 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 liquid phase and the standard molar enthalpies of phase transition, as (106.8 ± 1.1) kJ . mol -1 , -(207.4 ± 1.3) kJ . mol -1 , and -(151.9 ± 1.1) kJ . mol -1 , for 2-furancarbonitrile, 2-acetylfuran, and 3-furaldehyde, respectively. Standard molar enthalpies of formation are discussed in terms of the isomerization ortho meta. Enthalpic increment values of the introduction of the functional groups -CN, -CHO, and -COCH 3 were also compared with some other heterocycles; i.e. thiophene and pyridine

Formation enthalpies of Al–Fe–Zr–Nd system calculated by using geometric and Miedema's models

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lei [Department of Mathematics and Information Science, Guangxi College of Education, Nanning 530023 (China); Wang, Rongcheng; Tao, Xiaoma; Guo, Hui; Chen, Hongmei [College of Physical Science and Technology, Guangxi University, Nanning 530004 (China); Ouyang, Yifang, E-mail: ouyangyf@gxu.edu.cn [College of Physical Science and Technology, Guangxi University, Nanning 530004 (China)

2015-04-15

Formation enthalpy is important for the phase stability and amorphous forming ability of alloys. The formation enthalpies of Fe{sub 17}RE{sub 2} (RE=Ce, Pr, Nd, Gd and Er) obtained by Miedema's theory are in good agreement with those of the experiments. The dependence of formation enthalpy on concentration of Al for intermetallic (Al{sub x}Fe{sub 1−x}){sub 17}Nd{sub 2} have been calculated by Miedema's theory and the geometric model. The solid solubility of Al in (Al{sub x}Fe{sub 1−x}){sub 17}Nd{sub 2} is coincident with the concentration dependence of formation enthalpy. The mixing enthalpies of liquid alloys and formation enthalpies of alloys for Al–Fe–Zr–Nd system have been predicted. The calculated mixing enthalpy indicates that the adding of Fe or Nd decreases monotonously the magnitude of enthalpy. The formation enthalpies of Al–Fe–Zr–Nd system indicate that the shape of the enthalpy contour map changes when the content of Al is less than 50.0 at% and then it remains unchanged except the decrease of magnitude. The formation enthalpy of Al–Fe–Zr–Nd increases with the increase of Fe and/or Nd content. The negative formation enthalpy indicates that Al–Fe–Zr–Nd system has higher amorphous forming ability and wide amorphous forming range. The certain contents of Zr and/or Al are beneficial for the formation of Al–Fe–Zr–Nd intermetallics.

High-temperature enthalpies of plutonium monocarbide and plutonium sesquicarbide

International Nuclear Information System (INIS)

Oetting, F.L.

1979-01-01

The high-temperature enthalpies of plutonium monocarbide and plutonium sesquicarbide have been determined with a copper-block calorimeter of the isoperibol type. The experimental enthalpy data, which was measured relative to 298 K, covered the temperature range from 400 to 1500 K. The calculation of the temperature rise of the calorimeter takes into account the added heat evolution from the radioactive decay of the plutonium samples. These enthalpy results, combined with the heat capacity and entropy of the respective carbide at 298 K available from the literature, has made it possible to generate tables of thermodynamic functions for the plutonium carbides. The behavior of the heat capacity of both of the plutonium carbides, i.e., a relatively steep increase in the heat capacity as the temperature increases, may be attributed to a premelting effect with the formation of vacancies within the crystal lattice although a theoretical treatment of this phenomenon is not given

A correct enthalpy relationship as thermal comfort index for livestock.

Science.gov (United States)

Rodrigues, Valéria Cristina; da Silva, Iran José Oliveira; Vieira, Frederico Márcio Corrêa; Nascimento, Sheila Tavares

2011-05-01

Researchers working with thermal comfort have been using enthalpy to measure thermal energy inside rural facilities, establishing indicator values for many situations of thermal comfort and heat stress. This variable turned out to be helpful in analyzing thermal exchange in livestock systems. The animals are exposed to an environment which is decisive for the thermoregulatory process, and, consequently, the reactions reflect states of thermal comfort or heat stress, the last being responsable for problems of sanity, behavior and productivity. There are researchers using enthalpy as a qualitative indicator of thermal environment of livestock such as poultry, cattle and hogs in tropical regions. This preliminary work intends to check different enthalpy equations using information from classical thermodynamics, and proposes a direct equation as thermal comfort index for livestock systems.

Structure of metal β-diketonates and their enthalpies of vaporization

International Nuclear Information System (INIS)

Domrachev, G.A.; Sevast'yanov, V.G.; Zakharov, L.N.; Krasnodubskaya, S.V.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

1987-01-01

Using the method of additive schemes in combinaion with the structural estimation of the degree of screening of the central atom and other elements of β-diketonate molecule while analyzing the experimental enthalpies of vaporization, the contributions of separate fragments of complexes into the enthalpy of vaporization are found. It is shown that energies of intermolecular interaction in a condensed phase of monomeric metal β-diketonates with identical substituents do not depend on the central atom type. The enthalpies of dimer dissociation in a series of rare earth dipivaloylmethanates calculated. The proposed approach is advisable fo selecting forms of metal β-diketonates, the most suitable for the purposes of deep purificaion, which are characterized by maximum chemical and physico-chemical selectivity with respect to impurities, chemical inertness to equipment material, container, etc

Design and Analysis of MEMS Linear Phased Array

Directory of Open Access Journals (Sweden)

Guoxiang Fan

2016-01-01

Full Text Available A structure of micro-electro-mechanical system (MEMS linear phased array based on “multi-cell” element is designed to increase radiation sound pressure of transducer working in bending vibration mode at high frequency. In order to more accurately predict the resonant frequency of an element, the theoretical analysis of the dynamic equation of a fixed rectangular composite plate and finite element method simulation are adopted. The effects of the parameters both in the lateral and elevation direction on the three-dimensional beam directivity characteristics are comprehensively analyzed. The key parameters in the analysis include the “cell” number of element, “cell” size, “inter-cell” spacing and the number of elements, element width. The simulation results show that optimizing the linear array parameters both in the lateral and elevation direction can greatly improve the three-dimensional beam focusing for MEMS linear phased array, which is obviously different from the traditional linear array.

Temperatures and enthalpies of melting of alkali-metal perrhenates

International Nuclear Information System (INIS)

Lukas, W.; Gaune-Escard, M.

1982-01-01

Melting temperatures and enthalpies of melting were determined for alkali-metal perrhenates by differential enthalpic analysis using a high-temperature Calvet microcalorimeter. The following values were obtained: for LiReO 4 : 692 K and 24.9 kJ.mol -1 ; for NaReO 4 : 693 K and 33 kJ.mol -1 ; for KReO 4 : 828 K and 36 kJ.mol -1 ; for RbReO 4 : 878 K and 34 kJ.mol -1 ; for CsReO 4 : 893 K and 34 kJ.mol -1 . (author)

Formation enthalpy of NiBe and Ni5Be21

International Nuclear Information System (INIS)

Ivanov, M.I.; Karpova, T.F.; Dalago, N.Yu.

1981-01-01

The method of dissolution calorimetry is used to determine standard enthalpies of NiBe and Ni 5 Be 21 formation, which are 84.8+-2.2 and (-669+-37)kJ/mol. The enthalpy values of NiBe and Ni 5 Be 21 at 331 K are shown to coincide (within the limits of errors of these values) with the values at the standard temperature of 298.15 K [ru

Enthalpy of sublimation/vaporization of trans-cyclohexyl-1,4-diamine and cis-cyclohexyl-1,2-diamine

OpenAIRE

Tomé, Luciana I. N.; Rosado, Mário T. S.; Nunes, Sandra C. C.; Maria, Teresa M. R.; Canotilho, João; Eusébio, M. Ermelinda S.

2007-01-01

The molar enthalpy of sublimation, , of trans-cyclohexyl-1,4-diamine and the molar enthalpy of vaporization, , of cis-cyclohexyl-1,2-diamine, at the temperature 298.15 K, were determined by calorimetry. was obtained for the trans-isomer and for the cis form. The molar enthalpy of fusion of the first compound, at T = 342.1 K, was determined by differential scanning calorimetry. The molar enthalpy of vaporization of the 1,4-isomer was estimated by combining the value of the enthalpy of sublimat...

Enthalpies of formation of dihydroxybenzenes revisited: Combining experimental and high-level ab initio data

International Nuclear Information System (INIS)

Gonçalves, Elsa M.; Agapito, Filipe; Almeida, Tânia S.; Martinho Simões, José A.

2014-01-01

Highlights: • Thermochemistry of hydroxyphenols probed by experimental and theoretical methods. • A new paradigm for obtaining enthalpies of formation of crystalline compounds. • High-level ab initio results for the thermochemistry of gas-phase hydroxyphenols. • Sublimation enthalpies of hydroxyphenols determined by Calvet microcalorimetry. - Abstract: Accurate values of standard molar enthalpies of formation in condensed phases can be obtained by combining high-level quantum chemistry calculations of gas-phase enthalpies of formation with experimentally determined enthalpies of sublimation or vapourization. The procedure is illustrated for catechol, resorcinol, and hydroquinone. Using W1-F12, the gas-phase enthalpies of formation of these compounds at T = 298.15 K were computed as (−270.6, −269.4, and −261.0) kJ · mol −1 , respectively, with an uncertainty of ∼0.4 kJ · mol −1 . Using well characterised solid samples, the enthalpies of sublimation were determined with a Calvet microcalorimeter, leading to the following values at T = 298.15 K: (88.3 ± 0.3) kJ · mol −1 , (99.7 ± 0.4) kJ · mol −1 , and (102.0 ± 0.9) kJ · mol −1 , respectively. It is shown that these results are consistent with the crystalline structures of the compounds

Vaporization thermodynamics and enthalpy of formation of aluminum silicon carbide

International Nuclear Information System (INIS)

Behrens, R.G.; Rinehart, G.H.

1984-01-01

The vaporization thermodynamics of aluminum silicon carbide was investigated using Knudsen effusion mass spectrometry. Vaporization occurred incongruently to give Al(g), SiC(s), and graphite as reaction products. The vapor pressure of aluminum above (Al 4 SiC 4 + SiC + C) was measured using graphite effusion cells with orifice areas between 1.1 X 10 -2 and 3.9 X 10 -4 cm 2 . The vapor pressure of aluminum obtained between 1427 and 1784 K using an effusion cell with the smallest orifice area, 3.9 X 10 -4 cm 2 , is expressed as log p (Pa) = - (18567 + or - 86) (K/T) + (12.143 + or - 0.054) The third-law calculation of the enthalpy change for the reaction Al 4 SiC 4 (s) = 4Al(g) + SiC(hex) + 3C(s) using the present aluminum pressures gives ΔH 0 (298.15 K) = (1455 + or - 79) kJ /SUP ./ mol -1 . The corresponding second-law result is ΔH 0 (298.15 K) = (1456 + or - 47) kJ /SUP ./ mol -1 . The standard enthalpy of formation of Al 4 SiC 4 (s) from the elements calculated from the present vaporization enthalpy (third-law calculation) and the enthalpies of formation of Al(g) and hexagonal SiC is ΔH 0 /SUB f/ (298.15 K) = -(221 + or - 85) kJ /SUP ./ mol -1 . The standard enthalpy of formation of Al 4 SiC 4 (s) from its constituent carbides Al 4 C 3 (s) and SiC(c, hex) is calculated to be ΔH 0 (298.15 K) = (38 + or - 92) KJ /SUP ./ mol -1

Analysis of measurements on wind turbine arrays. Vol. 1

International Nuclear Information System (INIS)

Hoeg, E.

1990-12-01

In 1989 a Danish electric power company initiated an analysis of eight wind turbine arrays. Data from this project is presented together with the explained results of the analyses and the output variations for individual arrays and for systems within the arrays. The models for prognosis are compared and evaluated in order to find that which is most effective. (AB)

Experimental standard molar enthalpies of formation of some methylbenzenediol isomers

International Nuclear Information System (INIS)

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

2009-01-01

The present work is part of a research program on the energetics of formation of alkyl substituted benzenediols, aiming the study of the enthalpic effect of the introduction of methyl substituents into benzenediols. In this work we present the results of the thermochemical research on 2-methylresorcinol, 3-methylresorcinol, 4-methylresorcinol, and methylhydroquinone. The standard (p 0 =0.1MPa) molar enthalpies of formation, in the crystalline phase, at T = 298.15 K, of the compounds mentioned above were derived from their standard massic energies of combustion, measured by static-bomb combustion calorimetry, while the standard molar enthalpies of sublimation of those compounds were obtained by the temperature dependence of their vapour pressures determined by the Knudsen effusion technique. From experimental values, the standard molar enthalpies of formation of the studied methylbenzenediols in the gaseous phase, at T = 298.15 K were then derived. The results are interpreted in terms of structural contributions to the energetics of the substituted benzenediols and compared with the same parameters estimated from the Cox Scheme. Moreover, the standard (p 0 =0.1MPa) molar enthalpies, entropies, and Gibbs energies of sublimation, at T = 298.15 K, were derived for the four isomers of methylbenzenediols.

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

African Journals Online (AJOL)

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 K in an isothermal displacement calorimeter with vapour space. A significantly increasing trend in the endothermic excess enthalpy values for ...

Vapour pressures and enthalpies of vaporization of a series of the ferrocene derivatives

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Verevkin, Sergey P.; Krol, Olesya V.; Varushchenko, Raisa M.; Chelovskaya, Nelly V.

2007-01-01

Vapour pressures of the ferrocene, ferrocene-methanol, benzyl-ferrocene, and benzoyl-ferrocene have been determined by the transpiration method. The molar enthalpies of sublimation Δ cr g H m and of vaporization Δ l g H m have been determined from the temperature dependence of the vapour pressure. The molar enthalpies of fusion of these compounds were measured by d.s.c. The measured data sets of vaporization, sublimation, and fusion enthalpies were checked for internal consistency

Enthalpies of formation of UAl1 and UAl3 by calorimetry

International Nuclear Information System (INIS)

Nagarajan, K.; Babu, R.; Mathews, C.K.

1993-01-01

Enthalpies of formation of the intermetallic compounds UAl 4 and UAl 3 at 298.15 K were determined by high temperature solution calorimetry in which liquid aluminium was used as the solvent. The thermal effects of dissolution of UAl 4 , UAl 3 and U in liquid aluminium were measured in separate experiments by dropping the samples held at the ambient temperature into liquid aluminium maintained at 980 K in the calorimeter. The thermal effects of dissolution of these samples at infinite dilution in liquid aluminium were derived from these measurements and based on this data the enthalpies of formation of UAl 4 and UAl 3 at 298.15 K were computed. The values obtained are ΔH f,298.15 (UAl 4 )=-126.5±13.3 kJ mol -1 and ΔH f,298.15 (UAl 3 )=-118.1±8.2 kJ mol -1 . The integral enthalpies of formation of U-Al alloys at 978 K, 1078 K and 1094 K were measured by dropping U samples maintained at the ambient temperature into liquid aluminium in the calorimeter at the experimental temperature. From the integral enthalpies of formation of U-Al alloys in the two phase regions, {U-Al}+ 4 > and {U-Al}+ 3 >, the enthalpies of formation of UAl 4 and UAl 3 , respectively, at the temperatures of measurement were derived. These results are discussed in comparison with the literature data. (orig.)

Insights on activation enthalpy for non-Schmid slip in body-centered cubic metals

International Nuclear Information System (INIS)

Hale, Lucas M.; Lim, Hojun; Zimmerman, Jonathan A.; Battaile, Corbett C.; Weinberger, Christopher R.

2015-01-01

We use insights gained from atomistic simulation to develop an activation enthalpy model for dislocation slip in body-centered cubic iron. Using a classical potential that predicts dislocation core stabilities consistent with ab initio predictions, we quantify the non-Schmid stress-dependent effects of slip. The kink-pair activation enthalpy is evaluated and a model is identified as a function of the general stress state. Our model enlarges the applicability of the classic Kocks activation enthalpy model to materials with non-Schmid behavior

Enthalpy-entropy compensation for the solubility of drugs in solvent mixtures: paracetamol, acetanilide, and nalidixic acid in dioxane-water.

Science.gov (United States)

Bustamante, P; Romero, S; Pena, A; Escalera, B; Reillo, A

1998-12-01

In earlier work, a nonlinear enthalpy-entropy compensation was observed for the solubility of phenacetin in dioxane-water mixtures. This effect had not been earlier reported for the solubility of drugs in solvent mixtures. To gain insight into the compensation effect, the behavior of the apparent thermodynamic magnitudes for the solubility of paracetamol, acetanilide, and nalidixic acid is studied in this work. The solubility of these drugs was measured at several temperatures in dioxane-water mixtures. DSC analysis was performed on the original powders and on the solid phases after equilibration with the solvent mixture. The thermal properties of the solid phases did not show significant changes. The three drugs display a solubility maximum against the cosolvent ratio. The solubility peaks of acetanilide and nalidixic acid shift to a more polar region at the higher temperatures. Nonlinear van't Hoff plots were observed for nalidixic acid whereas acetanilide and paracetamol show linear behavior at the temperature range studied. The apparent enthalpies of solution are endothermic going through a maximum at 50% dioxane. Two different mechanisms, entropy and enthalpy, are suggested to be the driving forces that increase the solubility of the three drugs. Solubility is entropy controlled at the water-rich region (0-50% dioxane) and enthalpy controlled at the dioxane-rich region (50-100% dioxane). The enthalpy-entropy compensation analysis also suggests that two different mechanisms, dependent on cosolvent ratio, are involved in the solubility enhancement of the three drugs. The plots of deltaH versus deltaG are nonlinear, and the slope changes from positive to negative above 50% dioxane. The compensation effect for the thermodynamic magnitudes of transfer from water to the aqueous mixtures can be described by a common empirical nonlinear relationship, with the exception of paracetamol, which follows a separate linear relationship at dioxane ratios above 50%. The

Standard molar enthalpies of formation of sodium alkoxides

International Nuclear Information System (INIS)

Chandran, K.; Srinivasan, T.G.; Gopalan, A.; Ganesan, V.

2007-01-01

The molar enthalpies of solution of sodium in methanol, ethanol, and n-propanol and of sodium alkoxides in their corresponding alcohols were measured at T=298.15K using an isoperibol solution calorimeter. From these results and other auxiliary data, the standard molar enthalpies of formation, Δ f H m o (RONa,cr) of sodium methoxide, sodium ethoxide, and sodium n-propoxide were calculated and found to be {(-366.21+/-1.38) (-413.39+/-1.45), and (-441.57+/-1.18)}kJ.mol -1 , respectively. A linear correlation has been found between Δ f H m o (RONa)andΔ f H m o (ROH) for R=n-alkyl, enabling the prediction of data for other sodium alkoxides

Standard molar enthalpies of formation of 2-, 3-, and 4-piperidinomethanol isomers

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Cabral, Joana I.T.A.

2006-01-01

The standard (p o =0.1MPa) molar energies of combustion in oxygen of 2-piperidinemethanol, 3-piperidinemethanol, and 4-piperidinemethanol, all in the crystalline phase, were measured, at T=298.15K, by static bomb calorimetry. These values were used to derive the standard molar enthalpies of combustion and the standard molar enthalpies of formation, in the condensed phase, for these compounds. Further, the standard molar enthalpies of sublimation, at T=298.15K, of these three piperidinomethanol isomers were determined by Cavet microcalorimetry. The combustion calorimetry results together with those from the Calvet microcalorimetry, were used to derive the standard molar enthalpies of formation, at T=298.15K, in the gaseous phase, of the three piperidinemethanol studied. -Δ c H m o (cr)Δ cr g H m o kJ.mol -1 kJ.mol -1 2-Piperidinemethanol3890.70+/-0.9293.02+/-0.503- Piperidinemethanol3895.3+/-1.195.9+/-1.44-Piperidinemethanol3891.3+/- 1.198.31+/-0.69

Experimental redetermination of the gas-phase enthalpy of formation of ethyl 2-thiophenecarboxylate

International Nuclear Information System (INIS)

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

2013-01-01

The condensed phase standard (p° = 0.1 MPa) molar enthalpy of formation of ethyl-2-thiophenecarboxylate was derived from the remeasured standard molar energy of combustion, in oxygen, at T = 298.15 K, by rotating bomb combustion calorimetry and the standard molar enthalpy of vaporization, at T = 298.15 K, remeasured by Calvet microcalorimetry. Combining these two values, the following enthalpy of formation in the gas phase, at T = 298.15 K, was then derived for ethyl-2-thiophenecarboxylate: −(277.7 ± 2.9) kJ · mol −1 . The calculated gas-phase enthalpy of formation of the title compound, through the G3(MP2)//B3LYP approach was found to be 278.9 kJ · mol −1 , in excellent agreement with the experimental measured value

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)

Analysis of experimental routines of high enthalpy steam discharge in subcooled water

International Nuclear Information System (INIS)

Pacheco, Rafael R.; Andrade, Delvonei A.

2015-01-01

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)

Fabrication of plasmonic cavity arrays for SERS analysis

Science.gov (United States)

Li, Ning; Feng, Lei; Teng, Fei; Lu, Nan

2017-05-01

The plasmonic cavity arrays are ideal substrates for surface enhanced Raman scattering analysis because they can provide hot spots with large volume for analyte molecules. The large area increases the probability to make more analyte molecules on hot spots and leads to a high reproducibility. Therefore, to develop a simple method for creating cavity arrays is important. Herein, we demonstrate how to fabricate a V and W shape cavity arrays by a simple method based on self-assembly. Briefly, the V and W shape cavity arrays are respectively fabricated by taking KOH etching on a nanohole and a nanoring array patterned silicon (Si) slides. The nanohole array is generated by taking a reactive ion etching on a Si slide assembled with monolayer of polystyrene (PS) spheres. The nanoring array is generated by taking a reactive ion etching on a Si slide covered with a monolayer of octadecyltrichlorosilane before self-assembling PS spheres. Both plasmonic V and W cavity arrays can provide large hot area, which increases the probability for analyte molecules to deposit on the hot spots. Taking 4-Mercaptopyridine as analyte probe, the enhancement factor can reach 2.99 × 105 and 9.97 × 105 for plasmonic V cavity and W cavity array, respectively. The relative standard deviations of the plasmonic V and W cavity arrays are 6.5% and 10.2% respectively according to the spectra collected on 20 random spots.

Crosstalk analysis of silicon-on-insulator nanowire-arrayed waveguide grating

International Nuclear Information System (INIS)

Li Kai-Li; An Jun-Ming; Zhang Jia-Shun; Wang Yue; Wang Liang-Liang; Li Jian-Guang; Wu Yuan-Da; Yin Xiao-Jie; Hu Xiong-Wei

2016-01-01

The factors influencing the crosstalk of silicon-on-insulator (SOI) nanowire arrayed waveguide grating (AWG) are analyzed using the transfer function method. The analysis shows that wider and thicker arrayed waveguides, outsider fracture of arrayed waveguide, and larger channel space, could mitigate the deterioration of crosstalk. The SOI nanowire AWGs with different arrayed waveguide widths are fabricated by using deep ultraviolet lithography (DUV) and inductively coupled plasma etching (ICP) technology. The measurement results show that the crosstalk performance is improved by about 7 dB through adopting 800 nm arrayed waveguide width. (paper)

Enthalpy of solution of potassium iodide in the water-formamide-dimethyl sulfoxide mixtures

International Nuclear Information System (INIS)

Belova, L.N.; Solov'ev, S.N.; Vorob'ev, A.F.

1985-01-01

Solution enthalpies are measured for potassium iodide in the water-formamide-dimethyl sulfoxide mixtures in a sealed oscillating calorimeter with an isothermal shell at a constant water molar fraction equal to 0.3; 0.5 and 0.7 at 298.15 K. A diagram of the dependence of solution enthalpies on the of mixed solvent composition is plotted. Deviations of experimental solution enthalpies from the calculated ones are negative over the entire concentration range studied, which testifies to the preferable solvatation of electrolyte by the formid and dimthyl sulfoxide molecules

Experimental standard molar enthalpies of formation of some 4-alkoxybenzoic acids

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Lobo Ferreira, Ana I.M.C.; Maciel, Fabrice M.

2010-01-01

The present work is part of a research program on the energetics of the linear 4-n-alkoxybenzoic acids, aiming the study of the enthalpic effect of the introduction of an alkoxy chain in the position 4- of the benzoic acid ring. In this work, we present the results of the thermochemical research on 4-n-alkoxybenzoic acids with the alkoxy chain length n = 2, 4, and 8. The standard (p 0 =0.1MPa) molar enthalpy of formation of crystalline 4-ethoxybenzoic acid, 4-butoxybenzoic acid, and 4-(octyloxy)benzoic acid was measured, at T = 298.15 K, by static-bomb calorimetry. These values, combined with the values of standard molar enthalpies of sublimation, were used to derive the standard molar enthalpies of formation in the gaseous phase.

Analysis and synthesis of (SAR) waveguide phased array antennas

Science.gov (United States)

Visser, H. J.

1994-02-01

This report describes work performed due to ESA contract No. 101 34/93/NL/PB. Started is with a literature study on dual polarized waveguide radiators, resulting in the choice for the open ended square waveguide. After a thorough description of the mode matching infinite waveguide array analysis method - including finiteness effects - that forms the basis for all further described analysis and synthesis methods, the accuracy of the analysis software is validated by comparison with measurements on two realized antennas. These antennas have centered irises in the waveguide apertures and a dielectric wide angle impedance matching sheet in front of the antenna. A synthesis method, using simulated annealing and downhill simplex, is described next and different antenna designs, based on the analysis of a single element in an infinite array environment, are presented. Next, designs of subarrays are presented. Shown is the paramount importance of including the array environment in the design of a subarray. A microstrip patch waveguide exciter and subarray feeding network are discussed and the depth of the waveguide radiator is estimated. Chosen is a rectangular grid array with waveguides of 2.5 cm depth without irises and without dielectric sheet, grouped in linear 8 elements subarrays.

Recommended sublimation pressure and enthalpy of benzene

Czech Academy of Sciences Publication Activity Database

Růžička, K.; Fulem, Michal; Červinka, C.

2014-01-01

Roč. 68, Jan (2014), s. 40-47 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal - gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

Enthalpy of vaporization and vapor pressure of whiskey lactone and menthalactone by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Chickos, James

2017-01-01

Highlights: • The vapor pressure and vaporization enthalpies of cis and trans-whiskey lactone have been evaluated. • Enthalpies of vaporization and vapor pressures of (+)-isomintlactone and (−)-mintlactone were also evaluated. • The sublimation enthalpy and corresponding vapor pressure of (+) -isomintlactone at T = 298.15 K is estimated. - Abstract: Enthalpies of vaporization at T = 298.15 K of cis and trans-whiskey lactone have been evaluated by correlation gas chromatography to be (68.4 ± 1.7) kJ·mol −1 and (67.5 ± 1.7) kJ·mol −1 , respectively. The enthalpies of vaporization of isomintlactone and mintlactone also evaluated by correlation gas chromatography have been found to have vaporization enthalpies of (74.2 ± 1.8) kJ·mol −1 and (73.2 ± 1.8) kJ·mol −1 respectively. The vapor pressures for cis and trans-whiskey lactone at T = 298.15 K have been evaluated as (1.5 ± 0.09) Pa and (2.0 ± 0.1) Pa using vapor pressures of a series of lactones as standards. Vapor pressures for isomintlactone and mintlactone were evaluated as (0.26 ± 0.012) Pa and (0.33 ± 0.02) Pa, respectively. Fusion and sublimation enthalpies for (+)-isomintlactone as well as the vapor pressure of the solid have been estimated.

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.

Enthalpy of mixing of liquid Ag–Bi–Cu alloys at 1073 K

International Nuclear Information System (INIS)

Fima, Przemysław; Flandorfer, Hans

2014-01-01

Highlights: • Partial and integral mixing enthalpies of liquid Ag–Bi–Cu alloys were determined. • Integral mixing enthalpies are small and endothermic, similar to limiting binaries. • The ternary data were fitted on the basis of Redlich–Kister–Muggianu model. - Abstract: The Ag–Bi–Cu system is among those ternary systems which have not been fully studied yet, in particular the thermodynamic description of the liquid phase is missing. Partial and integral enthalpies of mixing of liquid ternary Ag–Bi–Cu alloys were determined over a broad composition range along six sections: x(Ag)/x(Bi) = 0.25, 1, 4; x(Ag)/x(Cu) = 1.5; x(Bi)/x(Cu) = 1.86, 4. Measurements were carried out at 1073 K using two Calvet type microcalorimeters and drop calorimetric technique. It was found that integral enthalpies of mixing are small and endothermic, similarly to limiting binary alloys. The ternary data were fitted on the basis of an extended Redlich–Kister–Muggianu model for substitutional solutions. There are no significant additional ternary interactions

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.

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.

The enthalpy of sublimation and thermodynamic functions of fermium

International Nuclear Information System (INIS)

Haire, R.G.; Gibson, J.K.

1989-01-01

The enthalpy of sublimation of fermium (Fm), element 100, has now been determined directly by measuring the partial pressure of Fm over alloys, for the temperature range of 642 to 905 K. The partial pressures were determined using Knudsen effusion and target collection techniques. Dilute (10 -5 --10 -7 atom %) solid alloys of Fm and mixtures of Fm and Es in both Sm and Yb solvents were studied. The presence of Es in two of the alloys allowed a direct comparison of the behavior of Fm and Es, where the latter could be used as a reference. It was possible to calculate enthalpies of sublimation and a hypothetical vapor pressure/temperature relationship for pure Fm metal by selecting Yb as the solvent most likely to form a nearly ideal alloy with Fm. From the experimental vapor pressure data, we derived average Second Law values of 33.8±3 kcal/mol and 23.5±3 cal/mol deg for the enthalpy and entropy of sublimation of Fm at 298 K. Third Law enthalpy values were also calculated using the experimental partial pressure data and entropies estimated from derived free energy functions and heat capacities for the solid and gaseous forms of Fm. The average Third Law values (34.8 kcal/mol and 25.1 cal/mol deg, respectively, at 298 K) are in agreement with those obtained via the Second Law. These results establish that Fm, like Es (element 99), is a divalent metal. The finding that Fm metal is the second divalent actinide element experimentally establishes the trend towards metallic divalency expected in the second half of the actinide series

Standard enthalpy of formation of Sm6UO12 acid dissolution calorimetry

International Nuclear Information System (INIS)

Venkata Krishnan, R.; Jogeswararao, G.; Ananthasivan, K.

2016-01-01

The standard molar enthalpies of formation of Δ f (298 K) of Sm 6 UO 12 have been determined by using an indigenously developed isoperibol acid solution calorimeter. The water equivalent of this calorimeter was determined by electrical calibration. The accuracy of measurement were determined by using standard materials KCl and tris(hydroxyl methyl) amino-methane (TRIS) and was found to be within ±2%. The enthalpies of solution at 298 K of Sm 2 O 3 , UO 3 and Sm 6 UO 12 were measured by using this calorimeter. From these experimental results the enthalpies of formation of Sm 6 UO 12 at 298 K were computed by using Hess's law of summation. (author)

An Empirical Study of Precise Interprocedural Array Analysis

Directory of Open Access Journals (Sweden)

Michael Hind

1994-01-01

Full Text Available In this article we examine the role played by the interprocedural analysis of array accesses in the automatic parallelization of Fortran programs. We use the PTRAN system to provide measurements of several benchmarks to compare different methods of representing interprocedurally accessed arrays. We examine issues concerning the effectiveness of automatic parallelization using these methods and the efficiency of a precise summarization method.

Reliability analysis of the solar array based on Fault Tree Analysis

International Nuclear Information System (INIS)

Wu Jianing; Yan Shaoze

2011-01-01

The solar array is an important device used in the spacecraft, which influences the quality of in-orbit operation of the spacecraft and even the launches. This paper analyzes the reliability of the mechanical system and certifies the most vital subsystem of the solar array. The fault tree analysis (FTA) model is established according to the operating process of the mechanical system based on DFH-3 satellite; the logical expression of the top event is obtained by Boolean algebra and the reliability of the solar array is calculated. The conclusion shows that the hinges are the most vital links between the solar arrays. By analyzing the structure importance(SI) of the hinge's FTA model, some fatal causes, including faults of the seal, insufficient torque of the locking spring, temperature in space, and friction force, can be identified. Damage is the initial stage of the fault, so limiting damage is significant to prevent faults. Furthermore, recommendations for improving reliability associated with damage limitation are discussed, which can be used for the redesigning of the solar array and the reliability growth planning.

Reliability analysis of the solar array based on Fault Tree Analysis

Energy Technology Data Exchange (ETDEWEB)

Wu Jianing; Yan Shaoze, E-mail: yansz@mail.tsinghua.edu.cn [State Key Laboratory of Tribology, Department of Precision Instruments and Mechanology, Tsinghua University,Beijing 100084 (China)

2011-07-19

The solar array is an important device used in the spacecraft, which influences the quality of in-orbit operation of the spacecraft and even the launches. This paper analyzes the reliability of the mechanical system and certifies the most vital subsystem of the solar array. The fault tree analysis (FTA) model is established according to the operating process of the mechanical system based on DFH-3 satellite; the logical expression of the top event is obtained by Boolean algebra and the reliability of the solar array is calculated. The conclusion shows that the hinges are the most vital links between the solar arrays. By analyzing the structure importance(SI) of the hinge's FTA model, some fatal causes, including faults of the seal, insufficient torque of the locking spring, temperature in space, and friction force, can be identified. Damage is the initial stage of the fault, so limiting damage is significant to prevent faults. Furthermore, recommendations for improving reliability associated with damage limitation are discussed, which can be used for the redesigning of the solar array and the reliability growth planning.

Modelling of high-enthalpy, high-Mach number flows

International Nuclear Information System (INIS)

Degrez, G; Lani, A; Panesi, M; Chazot, O; Deconinck, H

2009-01-01

A review is made of the computational models of high-enthalpy flows developed over the past few years at the von Karman Institute and Universite Libre de Bruxelles, for the modelling of high-enthalpy hypersonic (re-)entry flows. Both flows in local thermo-chemical equilibrium (LTE) and flows in thermo-chemical non-equilibrium (TCNEQ) are considered. First, the physico-chemical models are described, i.e. the set of conservation laws, the thermodynamics, transport phenomena and chemical kinetics models. Particular attention is given to the correct modelling of elemental (LTE flows) and species (chemical non-equilibrium-CNEQ-flows) transport. The numerical algorithm, based on a state-of-the-art finite volume discretization, is then briefly described. Finally, selected examples are included to illustrate the capabilities of the developed solver. (review article)

Standard molar enthalpy of formation of 1-benzosuberone: An experimental and computational study

International Nuclear Information System (INIS)

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

2010-01-01

The energetics of 1-benzosuberone was studied by a combination of calorimetric techniques and computational calculations. The standard (p o = 0.1 MPa) molar enthalpy of formation of 1-benzosuberone, in the liquid phase, was derived from the massic energy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The standard molar enthalpy of vaporization, at T = 298.15 K, was measured by Calvet microcalorimetry. From these two parameters the standard (p o = 0.1 MPa) molar enthalpy of formation, in the gaseous phase, at T = 298.15 K, was derived: -(96.1 ± 3.4) kJ . mol -1 . The G3(MP2)//B3LYP composite method and appropriate reactions were used to computationally calculate the standard molar enthalpy of formation of 1-benzosuberone, in the gaseous phase, at T = 298.15 K. The computational results are in very good agreement with the experimental value.

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. PMID:26796523

Investigation of enthalpy and specific heat of the gallium-indium-tin eutectic alloy

International Nuclear Information System (INIS)

Roshchupkin, V.V.; Migaj, L.L.; Fordeeva, L.K.; Perlova, N.L.

1978-01-01

Enthalpy and specific heat of the fusible (melting point is 10.6 deg C) eutectic alloy (67% Ga - 20.5% In - 12.5% Sn according to mass) are determined by the mixing method. The determination was carried out in vacuum at the residual pressure of >= 1x10 -5 torr in the temperature range from 59.3 to 437.0 deg C. It is established that temperature dependence of alloy enthalpy is described by the equation: Hsub(t) - Hsub(0degC)=1.014+0.0879t-0.0000129 t 2 , where (Hsub(t) - Hsub(0degC)) is enthalpy, cal/g; t-temperature, deg C. Mean-square dispersion is +-0.6%. Temperature dependence of alloy specific heat in the temperature range under study was determined by differentiation of the equation obtained for enthalpy: Csub(p)=0.0879-0.000026t, where Csub(p)-specific heat, cal/gx deg. It is supposed that temperature increase makes it possible to decrease slightly specific heat

High Enthalpy Effects on Two Boundary Layer Disturbances in Supersonic and Hypersonic Flow

Science.gov (United States)

Wagnild, Ross Martin

The fluid flow phenomenon of boundary layer transition is a complicated and difficult process to model and predict. The importance of the state of the boundary layer with regard to vehicle design cannot be understated. The high enthalpy environment in which high speed vehicles operate in further complicates the transition process by adding several more degrees of freedom. In this environment, the internal properties of the gas can stabilize or destabilize the boundary layer as well as modify the disturbances that cause transition. In the current work, the interaction of two types of disturbances with the high enthalpy flow environment are analyzed. The first is known as a second mode disturbance, which is acoustic in nature. The second type is known as a transient growth disturbance and is associated with flows behind roughness elements. Theoretical analyses, linear stability analyses, and computation fluid dynamics (CFD) are used to determine the ways in which these disturbances interact with the high enthalpy environment as well as the consequences of these interactions. First, acoustic wave are directly studied in order to gain a basic understanding of the response of second mode disturbances in the high enthalpy boundary layer. Next, this understanding is used in interpreting the results of several computations attempting to simulate the flow through a high enthalpy flow facility as well as experiments attempting to take advantage of the acoustic interaction with the high enthalpy environment. Because of the difficulty in modeling these experiments, direct simulations of acoustic waves in a hypersonic flow of a gas with molecular vibration are performed. Lastly, compressible transient growth disturbances are simulated using a linear optimal disturbance solver as well as a CFD solver. The effect of an internal molecular process on this type of disturbance is tested through the use of a vibrational mode. It is the goal of the current work to reinforce the

Skin-friction measurements in high-enthalpy hypersonic boundary layers

Science.gov (United States)

Goyne, C. P.; Stalker, R. J.; Paull, A.

2003-06-01

Skin-friction measurements are reported for high-enthalpy and high-Mach-number laminar, transitional and turbulent boundary layers. The measurements were performed in a free-piston shock tunnel with air-flow Mach number, stagnation enthalpy and Reynolds numbers in the ranges of 4.4 6.7, 3 13 MJ kg(-1) and 0.16× 10(6) 21× 10(6) , respectively. Wall temperatures were near 300 K and this resulted in ratios of wall enthalpy to flow-stagnation enthalpy in the range of 0.1 0.02. The experiments were performed using rectangular ducts. The measurements were accomplished using a new skin-friction gauge that was developed for impulse facility testing. The gauge was an acceleration compensated piezoelectric transducer and had a lowest natural frequency near 40 kHz. Turbulent skin-friction levels were measured to within a typical uncertainty of ± 7%. The systematic uncertainty in measured skin-friction coefficient was high for the tested laminar conditions; however, to within experimental uncertainty, the skin-friction and heat-transfer measurements were in agreement with the laminar theory of van Driest (1952). For predicting turbulent skin-friction coefficient, it was established that, for the range of Mach numbers and Reynolds numbers of the experiments, with cold walls and boundary layers approaching the turbulent equilibrium state, the Spalding & Chi (1964) method was the most suitable of the theories tested. It was also established that if the heat transfer rate to the wall is to be predicted, then the Spalding & Chi (1964) method should be used in conjunction with a Reynolds analogy factor near unity. If more accurate results are required, then an experimentally observed relationship between the Reynolds analogy factor and the skin-friction coefficient may be applied.

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.

Enthalpies of Formation of Transition Metal Diborides: A First Principles Study

Directory of Open Access Journals (Sweden)

Catherine Colinet

2015-11-01

Full Text Available The enthalpies of formation of transition metals diborides in various structures have been obtained from density functional theory (DFT calculations in order to determine the ground state at T = 0 K and p = 0. The evolution of the enthalpies of formation along the 3D, 4D, and 5D series has been correlated to the considered crystal structures. In the whole, the calculated values of the enthalpies of formation of the diborides in their ground state are in good agreement with the experimental ones when available. The calculated values of the lattice parameters at T = 0 K of the ground state agree well with the experimental values. The total and partial electronic densities of states have been computed. Special features of the transition metal electronic partial density of states have been evidenced and correlated to the local environment of the atoms.

Analysis of Camera Arrays Applicable to the Internet of Things.

Science.gov (United States)

Yang, Jiachen; Xu, Ru; Lv, Zhihan; Song, Houbing

2016-03-22

The Internet of Things is built based on various sensors and networks. Sensors for stereo capture are essential for acquiring information and have been applied in different fields. In this paper, we focus on the camera modeling and analysis, which is very important for stereo display and helps with viewing. We model two kinds of cameras, a parallel and a converged one, and analyze the difference between them in vertical and horizontal parallax. Even though different kinds of camera arrays are used in various applications and analyzed in the research work, there are few discussions on the comparison of them. Therefore, we make a detailed analysis about their performance over different shooting distances. From our analysis, we find that the threshold of shooting distance for converged cameras is 7 m. In addition, we design a camera array in our work that can be used as a parallel camera array, as well as a converged camera array and take some images and videos with it to identify the threshold.

Enthalpies of solution of ampicillin, amoxycillin and their binary mixtures at 310.15 K.

Science.gov (United States)

Jain, D V; Kashid, N; Kapoor, S; Chadha, R

2000-05-15

Enthalpies of solutions of ampicillin, amoxycillin and their binary mixtures have been determined at pH 2, 5, and 7 using C-80 calorimeter. The systems showed endothermic behaviour; molar enthalpies of solutions of ampicillin were determined to be 13.32, 15.89 and 23.21 kJ mol(-1) and amoxycillin were 16.32, 18.45 and 26. 25 kJ mol(-1) at pH 2, 5, and 7, respectively. The excess molar enthalpies of solution have also been calculated to find any interaction between these two drugs.

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, Carbochem(TM)-PS230, was modified by chemical and thermal treatment in flow of H(2), 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 pK(a). 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).

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

Directory of Open Access Journals (Sweden)

Liliana Giraldo

2011-12-01

Full Text Available 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.

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

International Nuclear Information System (INIS)

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

2005-01-01

The enthalpies of formation of seven uranyl oxide hydrate phases and one uranate have been determined using high-temperature oxide melt solution calorimetry: [(UO 2 ) 4 O(OH) 6 ](H 2 O) 5 , metaschoepite; β-UO 2 (OH) 2 ; CaUO 4 ; Ca(UO 2 ) 6 O 4 (OH) 6 (H 2 O) 8 , becquerelite; Ca(UO 2 ) 4 O 3 (OH) 4 (H 2 O) 2 ; Na(UO 2 )O(OH), clarkeite; Na 2 (UO 2 ) 6 O 4 (OH) 6 (H 2 O) 7 , the sodium analogue of compreignacite and Pb 3 (UO 2 ) 8 O 8 (OH) 6 (H 2 O) 2 , curite. The enthalpy of formation from the binary oxides, ΔH f-ox , at 298 K was calculated for each compound from the respective drop solution enthalpy, ΔH ds . The standard enthalpies of formation from the elements, ΔH f 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 -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

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

International Nuclear Information System (INIS)

Riveros, Diana C.; Martínez, Fleming; Vargas, Edgar F.

2012-01-01

Highlights: ► The solution enthalpies of methylcalix[4]resorcinarene in alcohols have been measured. ► The solution enthalpies of methylcalix[4]resorcinarene in alcohols are endothermic. ► 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.

Enthalpy recovery in glassy materials: Heterogeneous versus homogenous models

Science.gov (United States)

Mazinani, Shobeir K. S.; Richert, Ranko

2012-05-01

Models of enthalpy relaxations of glasses are the basis for understanding physical aging, scanning calorimetry, and other phenomena that involve non-equilibrium and non-linear dynamics. We compare models in terms of the nature of the relaxation dynamics, heterogeneous versus homogeneous, with focus on the Kovacs-Aklonis-Hutchinson-Ramos (KAHR) and the Tool-Narayanaswamy-Moynihan (TNM) approaches. Of particular interest is identifying the situations for which experimental data are capable of discriminating the heterogeneous from the homogeneous scenario. The ad hoc assumption of a single fictive temperature, Tf, is common to many models, including KAHR and TNM. It is shown that only for such single-Tf models, enthalpy relaxation of a glass is a two-point correlation function in reduced time, implying that experimental results are not decisive regarding the underlying nature of the dynamics of enthalpy relaxation. We also find that the restriction of the common TNM model to a Kohlrausch-Williams-Watts type relaxation pattern limits the applicability of this approach, as the particular choice regarding the distribution of relaxation times is a more critical factor compared with isothermal relaxation experiments. As a result, significant improvements in fitting calorimetry data can be achieved with subtle adjustments in the underlying relaxation time distribution.

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

KAUST Repository

Starikov, E.B.; Nordé n, B.

2012-01-01

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.

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.

Physical analysis for designing nested-wire arrays on Z-pinch implosion

International Nuclear Information System (INIS)

Yang Zhenhua; Liu Quan; Ding Ning; Ning Cheng

2005-01-01

Z-pinch experiments have demonstrated that the X-ray power increases 40% with a nested-wire array compared with that with a single-layered wire array. The design of the nested-wire array on Z accelerator is studied through the implosion dynamics and the growth of RT instabilities. The analysis shows that the nested-wire array does not produce more total X-ray radiation energy than the single-layered wire array, but it obviously increases the X-ray power. The radius of the outer array of the nested-wire array could be determined based on the radius of the optimized single-layered. The masses of the outer and inner arrays could be determined by the implosion time of the nested-wire array, which is roughly the same as that of the single-layered wire array. Some suggestions are put forward which may be helpful in the nested-wire array design for Z-pinch experiments. (authors)

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

African Journals Online (AJOL)

NJD

2004-07-01

Jul 1, 2004 ... NaBr and KBr in Mixed Ternary Solvent Systems at 298.15 K. Bal Raj Deshwala* ... industrial waters and their thermodynamic properties are of practical interest for .... The enthalpy of mixing (∆Hm) is the difference between the excess enthalpy of the ..... tural (categorized by softness, open- ness, and ...

Interface Enthalpy-Entropy Competition in Nanoscale Metal Hydrides

Directory of Open Access Journals (Sweden)

Nicola Patelli

2018-01-01

Full Text Available We analyzed the effect of the interfacial free energy on the thermodynamics of hydrogen sorption in nano-scaled materials. When the enthalpy and entropy terms are the same for all interfaces, as in an isotropic bi-phasic system, one obtains a compensation temperature, which does not depend on the system size nor on the relative phase abundance. The situation is different and more complex in a system with three or more phases, where the interfaces have different enthalpy and entropy. We also consider the possible effect of elastic strains on the stability of the hydride phase and on hysteresis. We compare a simple model with experimental data obtained on two different systems: (1 bi-phasic nanocomposites where ultrafine TiH2 crystallite are dispersed within a Mg nanoparticle and (2 Mg nanodots encapsulated by different phases.

Solution enthalpies of alkali metal halides in water and heavy water mixtures with dimethyl sulfoxide

International Nuclear Information System (INIS)

Egorov, G.I.

1994-01-01

Solution enthalpies of CsF, LiCl, NaI, CsI and some other halides of alkali metals and tetrabutylammonium have been measured by the method of calorimetry. Standard solution enthalpies of all alkali metals (except rubidium) halides in water and heavy water mixtures with dimethylsulfoxide at 298.15 K have been calculated. Isotopic effects in solvation enthalpy of the electrolytes mentioned in aqueous solutions of dimethylsulfoxide have been discussed. 29 refs., 2 figs., 4 tabs

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.

On the Enthalpy and Entropy of Point Defect Formation in Crystals

Science.gov (United States)

Kobelev, N. P.; Khonik, V. A.

2018-03-01

A standard way to determine the formation enthalpy H and entropy S of point defect formation in crystals consists in the application of the Arrhenius equation for the defect concentration. In this work, we show that a formal use of this method actually gives the effective (apparent) values of these quantities, which appear to be significantly overestimated. The underlying physical reason lies in temperature-dependent formation enthalpy of the defects, which is controlled by temperature dependence of the elastic moduli. We present an evaluation of the "true" H- and S-values for aluminum, which are derived on the basis of experimental data by taking into account temperature dependence of the formation enthalpy related to temperature dependence of the elastic moduli. The knowledge of the "true" activation parameters is needed for a correct calculation of the defect concentration constituting thus an issue of major importance for different fundamental and application issues of condensed matter physics and chemistry.

Study of Shallow Low-Enthalpy Geothermal Resources Using Integrated Geophysical Methods

Science.gov (United States)

De Giorgi, Lara; Leucci, Giovanni

2015-02-01

The paper is focused on low enthalpy geothermal exploration performed in south Italy and provides an integrated presentation of geological, hydrogeological, and geophysical surveys carried out in the area of municipality of Lecce. Geological and hydrogeological models were performed using the stratigraphical data from 51 wells. A ground-water flow (direction and velocity) model was obtained. Using the same wells data, the ground-water annual temperature was modeled. Furthermore, the ground surface temperature records from ten meteorological stations were studied. This allowed us to obtain a model related to the variations of the temperature at different depths in the subsoil. Integrated geophysical surveys were carried out in order to explore the low-enthalpy geothermal fluids and to evaluate the results of the model. Electrical resistivity tomography (ERT) and self-potential (SP) methods were used. The results obtained upon integrating the geophysical data with the models show a low-enthalpy geothermal resource constituted by a shallow ground-water system.

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.

Parametric analysis of ATM solar array.

Science.gov (United States)

Singh, B. K.; Adkisson, W. B.

1973-01-01

The paper discusses the methods used for the calculation of ATM solar array performance characteristics and provides the parametric analysis of solar panels used in SKYLAB. To predict the solar array performance under conditions other than test conditions, a mathematical model has been developed. Four computer programs have been used to convert the solar simulator test data to the parametric curves. The first performs module summations, the second determines average solar cell characteristics which will cause a mathematical model to generate a curve matching the test data, the third is a polynomial fit program which determines the polynomial equations for the solar cell characteristics versus temperature, and the fourth program uses the polynomial coefficients generated by the polynomial curve fit program to generate the parametric data.

Ionic liquids. Combination of combustion calorimetry with high-level quantum chemical calculations for deriving vaporization enthalpies.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas; Schick, Christoph

2008-07-10

In this work, the molar enthalpies of formation of the ionic liquids [C2MIM][NO3] and [C4MIM][NO3] were measured by means of combustion calorimetry. The molar enthalpy of fusion of [C2MIM][NO3] was measured using differential scanning calorimetry. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the G3MP2 theory. We have used a combination of traditional combustion calorimetry with modern high-level ab initio calculations in order to obtain the molar enthalpies of vaporization of a series of the ionic liquids under study.

Vaporization, fusion and sublimation enthalpies of the dicarboxylic acids from C4 to C14 and C16

International Nuclear Information System (INIS)

Roux, Maria Victoria; Temprado, Manuel; Chickos, James S.

2005-01-01

The fusion enthalpies of the series butanedioic acid through to tetradecanedioic acid and hexadecanedioic acids have been measured by DSC. In addition to fusion, a number of solid-solid phase transitions have also been detected in these diacids. The vaporization enthalpies of these compounds have been measured by correlation gas chromatography using the vaporization enthalpies of butanedioic, hexanedioic and decanedioic acids as standards. The vaporization enthalpies of the diacids from C 4 to C 10 correlated linearly with the number of methylene groups present. Above C 10 , the vaporization enthalpies of C 11 -C 14 and C 16 begin to deviate from linearity. The vaporization enthalpies for these compounds are dependent on the temperature of the GC column used. Similar departure from linearity has also been observed previously in the sublimation enthalpies for these compounds. The results are discussed in terms of formation of a cyclic intramolecular hydrogen bonded network in the gas phase similar to the bimolecular association observed in smaller mono-carboxylic acids at ambient temperatures

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.

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.

Enthalpy of mixing of Sn-Cd system using high temperature Calvet microcalorimeter

International Nuclear Information System (INIS)

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

1993-01-01

The integral enthalpy of mixing of Sn + Cd alloys were determined at 690 K for mole fraction of cadmium (X Cd ) from 0.06 to 0.958. In the present study, the use of small quantities of metals and the determination of enthalpy of mixing of an endothermic reaction without stirring the bath solution. This was possible due to the high sensitivity of the Calvet calorimeter. (author). 3 refs., 3 tabs

Borate-polyol complexes in aqueous solution: determination of enthalpies by thermometric titrimetry.

Science.gov (United States)

Aruga, R

1985-06-01

Enthalpies for the reaction of borate with 1,2-ethanediol, 1,2-propanediol, 1,2,3-propanetriol and d-mannitol have been determined by thermometric titrimetry. From these enthalpies and equilibrium constants taken from the literature, corresponding entropies have been calculated. The data refer to aqueous solutions at 25 degrees and I = 1.0M (NaNO(3)). The results indicate reasons for the differences in the stabilities of the complexes.

Oligonucleotide arrays vs. metaphase-comparative genomic hybridisation and BAC arrays for single-cell analysis: first applications to preimplantation genetic diagnosis for Robertsonian translocation carriers.

Science.gov (United States)

Ramos, Laia; del Rey, Javier; Daina, Gemma; García-Aragonés, Manel; Armengol, Lluís; Fernandez-Encinas, Alba; Parriego, Mònica; Boada, Montserrat; Martinez-Passarell, Olga; Martorell, Maria Rosa; Casagran, Oriol; Benet, Jordi; Navarro, Joaquima

2014-01-01

Comprehensive chromosome analysis techniques such as metaphase-Comparative Genomic Hybridisation (CGH) and array-CGH are available for single-cell analysis. However, while metaphase-CGH and BAC array-CGH have been widely used for Preimplantation Genetic Diagnosis, oligonucleotide array-CGH has not been used in an extensive way. A comparison between oligonucleotide array-CGH and metaphase-CGH has been performed analysing 15 single fibroblasts from aneuploid cell-lines and 18 single blastomeres from human cleavage-stage embryos. Afterwards, oligonucleotide array-CGH and BAC array-CGH were also compared analysing 16 single blastomeres from human cleavage-stage embryos. All three comprehensive analysis techniques provided broadly similar cytogenetic profiles; however, non-identical profiles appeared when extensive aneuploidies were present in a cell. Both array techniques provided an optimised analysis procedure and a higher resolution than metaphase-CGH. Moreover, oligonucleotide array-CGH was able to define extra segmental imbalances in 14.7% of the blastomeres and it better determined the specific unbalanced chromosome regions due to a higher resolution of the technique (≈ 20 kb). Applicability of oligonucleotide array-CGH for Preimplantation Genetic Diagnosis has been demonstrated in two cases of Robertsonian translocation carriers 45,XY,der(13;14)(q10;q10). Transfer of euploid embryos was performed in both cases and pregnancy was achieved by one of the couples. This is the first time that an oligonucleotide array-CGH approach has been successfully applied to Preimplantation Genetic Diagnosis for balanced chromosome rearrangement carriers.

Oligonucleotide arrays vs. metaphase-comparative genomic hybridisation and BAC arrays for single-cell analysis: first applications to preimplantation genetic diagnosis for Robertsonian translocation carriers.

Directory of Open Access Journals (Sweden)

Laia Ramos

Full Text Available Comprehensive chromosome analysis techniques such as metaphase-Comparative Genomic Hybridisation (CGH and array-CGH are available for single-cell analysis. However, while metaphase-CGH and BAC array-CGH have been widely used for Preimplantation Genetic Diagnosis, oligonucleotide array-CGH has not been used in an extensive way. A comparison between oligonucleotide array-CGH and metaphase-CGH has been performed analysing 15 single fibroblasts from aneuploid cell-lines and 18 single blastomeres from human cleavage-stage embryos. Afterwards, oligonucleotide array-CGH and BAC array-CGH were also compared analysing 16 single blastomeres from human cleavage-stage embryos. All three comprehensive analysis techniques provided broadly similar cytogenetic profiles; however, non-identical profiles appeared when extensive aneuploidies were present in a cell. Both array techniques provided an optimised analysis procedure and a higher resolution than metaphase-CGH. Moreover, oligonucleotide array-CGH was able to define extra segmental imbalances in 14.7% of the blastomeres and it better determined the specific unbalanced chromosome regions due to a higher resolution of the technique (≈ 20 kb. Applicability of oligonucleotide array-CGH for Preimplantation Genetic Diagnosis has been demonstrated in two cases of Robertsonian translocation carriers 45,XY,der(13;14(q10;q10. Transfer of euploid embryos was performed in both cases and pregnancy was achieved by one of the couples. This is the first time that an oligonucleotide array-CGH approach has been successfully applied to Preimplantation Genetic Diagnosis for balanced chromosome rearrangement carriers.

Oligonucleotide Arrays vs. Metaphase-Comparative Genomic Hybridisation and BAC Arrays for Single-Cell Analysis: First Applications to Preimplantation Genetic Diagnosis for Robertsonian Translocation Carriers

Science.gov (United States)

Ramos, Laia; del Rey, Javier; Daina, Gemma; García-Aragonés, Manel; Armengol, Lluís; Fernandez-Encinas, Alba; Parriego, Mònica; Boada, Montserrat; Martinez-Passarell, Olga; Martorell, Maria Rosa; Casagran, Oriol; Benet, Jordi; Navarro, Joaquima

2014-01-01

Comprehensive chromosome analysis techniques such as metaphase-Comparative Genomic Hybridisation (CGH) and array-CGH are available for single-cell analysis. However, while metaphase-CGH and BAC array-CGH have been widely used for Preimplantation Genetic Diagnosis, oligonucleotide array-CGH has not been used in an extensive way. A comparison between oligonucleotide array-CGH and metaphase-CGH has been performed analysing 15 single fibroblasts from aneuploid cell-lines and 18 single blastomeres from human cleavage-stage embryos. Afterwards, oligonucleotide array-CGH and BAC array-CGH were also compared analysing 16 single blastomeres from human cleavage-stage embryos. All three comprehensive analysis techniques provided broadly similar cytogenetic profiles; however, non-identical profiles appeared when extensive aneuploidies were present in a cell. Both array techniques provided an optimised analysis procedure and a higher resolution than metaphase-CGH. Moreover, oligonucleotide array-CGH was able to define extra segmental imbalances in 14.7% of the blastomeres and it better determined the specific unbalanced chromosome regions due to a higher resolution of the technique (≈20 kb). Applicability of oligonucleotide array-CGH for Preimplantation Genetic Diagnosis has been demonstrated in two cases of Robertsonian translocation carriers 45,XY,der(13;14)(q10;q10). Transfer of euploid embryos was performed in both cases and pregnancy was achieved by one of the couples. This is the first time that an oligonucleotide array-CGH approach has been successfully applied to Preimplantation Genetic Diagnosis for balanced chromosome rearrangement carriers. PMID:25415307

Knudsen cell vaporization of rare earth nitrides: enthalpy of vaporization of HoN098

International Nuclear Information System (INIS)

Brown, R.C.; Clark, N.J.

1975-01-01

The enthalpy of vaporization of HoN 0 . 98 was measured by the weight-loss Knudsen cell technique using Motzfeldt-Whitman extrapolations to zero orifice area. A third-law enthalpy of vaporization of HoN 0 . 98 of 155.9 +- 5 kcal mole -1 was obtained compared to a second-law value of 162.0 +- 5 kcal mole -1 . Similar measurements on the nitrides of samarium, erbium, and ytterbium gave third-law enthalpies of vaporization of 126.8 +-- 5 kcal mole -1 ; 159.6 +- 5 kcal mole -1 , and 121.0 +- 5 kcal mole -1 , respectively. 7 tables

Power-feedwater enthalpy operating domain for SBWR applying Monte Carlo simulation

International Nuclear Information System (INIS)

Quezada-Garcia, S.; Espinosa-Martinez, E.-G.; Vazquez-Rodriguez, A.; Varela-Ham, J.R.; Espinosa-Paredes, G.

2014-01-01

In this work the analyses of the feedwater enthalpy effects on reactor power in a simplified boiling water reactor (SBWR) applying a methodology based on Monte Carlo's simulation (MCS), is presented. The MCS methodology was applied systematically to establish operating domain, due that the SBWR are not yet in operation, the analysis of the nuclear and thermalhydraulic processes must rely on numerical modeling, with the purpose of developing or confirming the design basis and qualifying the existing or new computer codes to enable reliable analyses. (author)

Effects of partitioned enthalpy of mixing on glass-forming ability

Energy Technology Data Exchange (ETDEWEB)

Song, Wen-Xiong; Zhao, Shi-Jin, E-mail: shijin.zhao@shu.edu.cn [Institute of Materials Science, Shanghai University, Shanghai 200072 (China)

2015-04-14

We explore the inherent reason at atomic level for the glass-forming ability of alloys by molecular simulation, in which the effect of partitioned enthalpy of mixing is studied. Based on Morse potential, we divide the enthalpy of mixing into three parts: the chemical part (Δ E{sub nn}), strain part (Δ E{sub strain}), and non-bond part (Δ E{sub nnn}). We find that a large negative Δ E{sub nn} value represents strong AB chemical bonding in AB alloy and is the driving force to form a local ordered structure, meanwhile the transformed local ordered structure needs to satisfy the condition (Δ E{sub nn}/2 + Δ E{sub strain}) < 0 to be stabilized. Understanding the chemical and strain parts of enthalpy of mixing is helpful to design a new metallic glass with a good glass forming ability. Moreover, two types of metallic glasses (i.e., “strain dominant” and “chemical dominant”) are classified according to the relative importance between chemical effect and strain effect, which enriches our knowledge of the forming mechanism of metallic glass. Finally, a soft sphere model is established, different from the common hard sphere model.

ATMAD: robust image analysis for Automatic Tissue MicroArray De-arraying.

Science.gov (United States)

Nguyen, Hoai Nam; Paveau, Vincent; Cauchois, Cyril; Kervrann, Charles

2018-04-19

Over the last two decades, an innovative technology called Tissue Microarray (TMA), which combines multi-tissue and DNA microarray concepts, has been widely used in the field of histology. It consists of a collection of several (up to 1000 or more) tissue samples that are assembled onto a single support - typically a glass slide - according to a design grid (array) layout, in order to allow multiplex analysis by treating numerous samples under identical and standardized conditions. However, during the TMA manufacturing process, the sample positions can be highly distorted from the design grid due to the imprecision when assembling tissue samples and the deformation of the embedding waxes. Consequently, these distortions may lead to severe errors of (histological) assay results when the sample identities are mismatched between the design and its manufactured output. The development of a robust method for de-arraying TMA, which localizes and matches TMA samples with their design grid, is therefore crucial to overcome the bottleneck of this prominent technology. In this paper, we propose an Automatic, fast and robust TMA De-arraying (ATMAD) approach dedicated to images acquired with brightfield and fluorescence microscopes (or scanners). First, tissue samples are localized in the large image by applying a locally adaptive thresholding on the isotropic wavelet transform of the input TMA image. To reduce false detections, a parametric shape model is considered for segmenting ellipse-shaped objects at each detected position. Segmented objects that do not meet the size and the roundness criteria are discarded from the list of tissue samples before being matched with the design grid. Sample matching is performed by estimating the TMA grid deformation under the thin-plate model. Finally, thanks to the estimated deformation, the true tissue samples that were preliminary rejected in the early image processing step are recognized by running a second segmentation step. We

Standard molar enthalpies of formation of copper(II) β-diketonates and monothio-β-diketonates

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Luis M.N.B.F.

2006-01-01

The standard (p o =0.1MPa) molar enthalpies of formation of the crystalline complexes of dibenzoylmethane (Hdbm), thenoyltrifluoroacetone (Httfa), monothiodibenzoylmethane (HdbmS), and monothiothenoyltrifluoroacetone (HttfaS) of copper(II) were determined, at T=298.15K, by high precision solution-reaction calorimetry. The standard molar enthalpies of sublimation of the copper(II) β-diketonate complexes were measured by high-temperature Calvet microcalorimetry. From the standard molar enthalpies of formation of the complexes in the gaseous state, the mean molar dissociation enthalpies copper(II)-ligand, m >(Cu-L), were derived. Δ f H m o (cr)Δ cr g H m o kJ.mol -1 kJ.mol -1 Bis(dibenzoylmethanate)copper(II), Cu(dbm) 2 -364.0+/-3.9230.7+/-8.2Bis(thenoyltrifluoroacetonate)copper(II), Cu(ttfa) 2 -1824.3+/-8.3167.9+/-7.4Bis(monothiodibenzoylmethanate)copper(II), Cu(dbmS) 2 35.6+/-7.7[241+/-15]Bis(monothiothenoyltrifluoroacetonate) copper(II), Cu(ttfaS) 2 -1405.7+/-8.3[177+/-15

The vapor pressure and enthalpy of vaporization of M-xylene

International Nuclear Information System (INIS)

Rothenberg, S.J.; Seiler, F.A.; Bechtold, W.E.; Eidson, A.F.

1988-01-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 ± 0.1 (SE) kj/ g·mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 (± 0.1) (SE) kjg·mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization (ΔCpdeg.) of 35 ± 3 (SE) J/g·mol·K over the temperature range studied. (author)

Calorimetric measurement of the enthalpy of extraction of uranyl nitrate by tri-n-amyl phosphate

International Nuclear Information System (INIS)

Srinivasan, T.G.; Vasudeva Rao, P.R.; Venugopal, V.; Sood, D.D.

2002-01-01

Enthalpy of extraction of uranyl nitrate by tri n-amyl phosphate (TAP) and its solutions in n-dodecane has been directly measured by solution calorimetry for the first time. Measurements have been made at 303±1 K, in both forward as well as the reverse extraction modes. The enthalpies of the accompanying reactions such as the dilution of the uranyl nitrate in the aqueous phase, the hydration of TAP, the mixing of TAP and n-dodecane, the mixing of the metal-solvate (UO 2 (NO 3 ) 2 ·2TAP) and n-dodecane and mixing of the metal-solvate and TAP have also been independently measured and used to derive both the equilibrium state enthalpies and the standard state enthalpies for the extraction. Two distinct standard states have been used for the organic phase, viz., 1) all solutes infinitely diluted in diluent (ΔH*) and 2) all solutes infinitely diluted in the water saturated extractant (ΔH 0 ). The results have been compared with the enthalpies of extraction measured by employing the temperature dependence of the distribution ratio as well as calorimetry reported in the literature for extraction of uranyl nitrate by TAP and TBP. (author)

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.

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...... and northern part of the country, as well as in many of the Aegean Islands. The aim of this work is to review the options for managing wind load by using low-enthalpy geothermal energy for electricity (through heat pump utilisation) according to the local energy demand....... 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...

Building blocks for ionic liquids: Vapor pressures and vaporization enthalpies of 1-(n-alkyl)-imidazoles

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Portnova, Svetlana V.; Verevkin, Sergey P.; Skrzypczak, Andrzej; Schubert, Thomas

2011-01-01

Highlights: → We measured vapor pressures of the 1-(n-alkyl)-imidazoles by transpiration method. → Variations on the alkyl chain length n were C 3 , C 5 -C 7 , and C 9 -C 10 . → Enthalpies of vaporization were derived from (p, T) dependencies. → Enthalpies of vaporization at 298.15 K were linear dependent on the chain length. - Abstract: Vapor pressures of the linear 1-(n-alkyl)-imidazoles with the alkyl chain C 3 , C 5 -C 7 , and C 9 -C 10 have been measured by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. A linear correlation of enthalpies of vaporization Δ l g H m (298.15 K) of the 1-(n-alkyl)-imidazoles with the chain length has been found.

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

International Nuclear Information System (INIS)

Arslan, Hüseyin

2015-01-01

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 Au /x 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 Au /x Cu = 1 at 900 K. • The activity of Sn shows negative deviation from ideality in the same conditions

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

Indian Academy of Sciences (India)

These include the implicit time stepping method of Voller & Cross. (1981), explicit enthalpy method of Tacke (1985), centroidal temperature correction method ... In variable viscosity method, viscosity is written as a function of liquid fraction.

PREDICTION OF THE MIXING ENTHALPIES OF BINARY LIQUID ALLOYS BY MOLECULAR INTERACTION VOLUME MODEL

Institute of Scientific and Technical Information of China (English)

H.W.Yang; D.P.Tao; Z.H.Zhou

2008-01-01

The mixing enthalpies of 23 binary liquid alloys are calculated by molecular interaction volume model (MIVM), which is a two-parameter model with the partial molar infinite dilute mixing enthalpies. The predicted values are in agreement with the experimental data and then indicate that the model is reliable and convenient.

Sensitivity Analysis of WEC Array Layout Parameters Effect on the Power Performance

DEFF Research Database (Denmark)

Ruiz, Pau Mercadé; Ferri, Francesco; Kofoed, Jens Peter

2015-01-01

This study assesses the effect that the array layout choice has on the power performance. To this end, a sensitivity analysis is carried out with six array layout parameters, as the simulation inputs, the array power performance (q-factor), as the simulation output, and a simulation model special...

Determination of the protonation enthalpy of humic acid by calorimetric titration technique

International Nuclear Information System (INIS)

Kimuro, Shingo; Kirishima, Akira; Sato, Nobuaki

2015-01-01

Graphical abstract: The thermodynamic quantities of protonation of humic acid were determined by the combination of potentiometric titration and calorimetric titration. It was observed that the protonation enthalpy and Gibbs free energy had been affected by pH of solution. As a result, the thermodynamics of the protonation reaction of humic acid is influenced by the polyelectrolyte effect and the heterogeneity. - Highlights: • We applied calorimetric titration technique to the protonation of humic acid. • The thermodynamic quantities of protonation of humic acid were determined. • The protonation enthalpy of humic acid is affected by the heterogeneity. • Gibbs free energy of the protonation is affected by the polyelectrolyte effect. - Abstract: In this study, the calorimetric titration technique was used to determine the protonation enthalpy of two reference humic acids and polyacrylic acid. First, we obtained the apparent protonation constant of two kinds of humic acid purchased from IHSS (International Humic Substances Society) and polyacrylic acid by potentiometric titration. Second, we obtained the protonation enthalpy of them by calorimetric titration. The protonation enthalpy of humic acid was affected by pH and the ionic strength of bulk solution. From the comparison of ΔH between humic acid and polyacrylic acid, it was concluded that the pH dependence of ΔH is attributed to the heterogeneity of humic acid. And ΔH of phenolic hydroxyl group in humic acid is strongly influenced by the electric double layer of humic acid’s surface. This is considered to be a reason of the ionic strength dependence of ΔH. On the other hand, Gibbs free energy of the protonation of humic acid is affected by the electrostatic attraction with the progress of dissociation of functional groups such as carboxyl group and phenolic hydroxyl group. Consequently, the thermodynamics of the protonation of humic acid is affected by the polyelectrolyte effect and the

Vapor pressures and vaporization enthalpy of codlemone by correlation gas chromatography

International Nuclear Information System (INIS)

Schultz, Shannon M.; Harris, Harold H.; Chickos, James S.

2015-01-01

Highlights: • The vaporization enthalpy of codlemone has been evaluated. • The vapor pressure of codlemone has been evaluated from T = (298.15 to T b ) K. • Vapor pressures for the 1-alkanols standards are available from T = (298.15 to 500) K. - Abstract: The vapor pressure and vaporization enthalpy of codlemone (trans, trans 8,10-dodecadien-1-ol), the female sex hormone of the codling moth is evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. A vaporization enthalpy of (92.3 ± 2.6) kJ · mol −1 and a vapor pressure, p/Pa = (0.083 ± 0.012) were evaluated at T = 298.15 K. An equation for the evaluation of vapor pressure from ambient temperature to boiling has been derived by correlation for codlemone. The calculated boiling temperature of T B = 389 K at p = 267 Pa is within the temperature range reported in the literature. A normal boiling temperature of T B = (549.1 ± 0.1) K is also estimated by extrapolation

ExonMiner: Web service for analysis of GeneChip Exon array data

Directory of Open Access Journals (Sweden)

Imoto Seiya

2008-11-01

Full Text Available Abstract Background Some splicing isoform-specific transcriptional regulations are related to disease. Therefore, detection of disease specific splice variations is the first step for finding disease specific transcriptional regulations. Affymetrix Human Exon 1.0 ST Array can measure exon-level expression profiles that are suitable to find differentially expressed exons in genome-wide scale. However, exon array produces massive datasets that are more than we can handle and analyze on personal computer. Results We have developed ExonMiner that is the first all-in-one web service for analysis of exon array data to detect transcripts that have significantly different splicing patterns in two cells, e.g. normal and cancer cells. ExonMiner can perform the following analyses: (1 data normalization, (2 statistical analysis based on two-way ANOVA, (3 finding transcripts with significantly different splice patterns, (4 efficient visualization based on heatmaps and barplots, and (5 meta-analysis to detect exon level biomarkers. We implemented ExonMiner on a supercomputer system in order to perform genome-wide analysis for more than 300,000 transcripts in exon array data, which has the potential to reveal the aberrant splice variations in cancer cells as exon level biomarkers. Conclusion ExonMiner is well suited for analysis of exon array data and does not require any installation of software except for internet browsers. What all users need to do is to access the ExonMiner URL http://ae.hgc.jp/exonminer. Users can analyze full dataset of exon array data within hours by high-level statistical analysis with sound theoretical basis that finds aberrant splice variants as biomarkers.

Determination of formation enthalpies of incongruently fusing compounds

Energy Technology Data Exchange (ETDEWEB)

Kesler, Ya.A.; Cheshnitskij, S.M.; Fotiev, A.A.; Tret' yakov, Yu.D.

1985-04-01

Using the method of drop-calorimetry i.e. drop into the calorimeter cell being at the specified temperature of the specimen thermostated at 298 K, for studying reactions of peritectic decomposition of compounds for determining their formation enthalpies is considered. The measurements have been performed at 973 K using high temperature double microcalorimeter. The values ..delta..H/sub 1/=(367.0 +- 2.8) kJ/mol and ..delta..H/sub 2/=)343.9 +- 3.1) kJ/mol are obtained as a result of two series of measurements (6 experiments in each). The advantage of the described technique consists in the fact that the value of enthalpy of compound formation is obtained as a result of direct calorimetric measurements while in the e.m.f. method this value is determined as a coefficient in the Gibbs energy temperature dependence. The method is simple and does not require much time (one measurement takes 30-40 min).

Determination of formation enthalpies of incongruently fusing compounds

International Nuclear Information System (INIS)

Kesler, Ya.A.; Cheshnitskij, S.M.; Fotiev, A.A.; Tret'yakov, Yu.D.

1985-01-01

Using the method of drop-calorimetry i.e. drop into the calorimeter cell being at the specified temperature of the specimen thermostated at 298 K, for studying reactions of peritectic decomposition of compounds for determining their formation enthalpies is considered. The measurements have been performed at 973 K using high temperature double microcalorimeter. The values ΔH 1 =(367.0+-2.8) kJ/mol and ΔH 2 =)343.9+-3.1) kJ/mol are obtained as a result of two series of measurements (6 experiments in each). The advantage of the described technique consists in the fact that the value of enthalpy of compound formation is obtained as a result of direct calorimetric measurements while in the e.m.f. method this value is determined as a coefficient in the Gibbs energy temperature dependence. The method is simple and does not require much time (one measurement takes 30-40 min)

Vaporization enthalpies of imidazolium based ionic liquids. A thermogravimetric study of the alkyl chain length dependence

International Nuclear Information System (INIS)

Verevkin, Sergey P.; Zaitsau, Dzmitry H.; Emel’yanenko, Vladimir N.; Ralys, Ricardas V.; Yermalayeu, Andrei V.; Schick, Christoph

2012-01-01

Highlights: ► Enthalpies of vaporization of ionic liquids were measured with thermogravimetry. ► We studied 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide. ► The linear alkyl chain length was 4, 6, 8, 10, 12, 14, 16, and 18 C-atoms. ► A linear dependence on the chain length of the alkyl-imidazolium cation was found. - Abstract: Vaporization enthalpies for a series of ten ionic liquids (ILs) 1-alkyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide [C n mim][NTf 2 ], with the alkyl chain length n = 4, 6, 8, 10, 12, 14, 16, and 18 were determined using the thermogravimetric method. An internally consistent set of experimental data and vaporization enthalpies at 540 K was obtained. Vaporization enthalpies at 540 K have shown a linear dependence on the chain length of the alkyl-imidazolium cation in agreement with the experimental results measured previously with a quartz crystal microbalance. Ambiguity of Δ l g C pm o -values required for the extrapolation of experimental vaporization enthalpies to the reference temperature 298 K has been discussed.

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.

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

The vapor pressure and enthalpy of vaporization of M-xylene

Energy Technology Data Exchange (ETDEWEB)

Rothenberg, S J; Seiler, F A; Bechtold, W E; Eidson, A F

1988-12-01

We measured the vapor pressure of m-xylene over the temperature range 273 to 293 deg K with a single-sided capacitance manometer. The enthalpy of vaporization was 42.2 {+-} 0.1 (SE) kj/ g{center_dot}mol. Combining our own data with previously published data, we recommend using the values 42.0, 40.6, and 39.1 ({+-} 0.1) (SE) kjg{center_dot}mol for the enthalpy of vaporization of m-xylene at 300, 340, and 380 deg. K, respectively, and a value for the change in heat capacity on vaporization ({delta}Cpdeg.) of 35 {+-} 3 (SE) J/g{center_dot}mol{center_dot}K over the temperature range studied. (author)

Exome Array Analysis of Nuclear Lens Opacity.

Science.gov (United States)

Loomis, Stephanie J; Klein, Alison P; Lee, Kristine E; Chen, Fei; Bomotti, Samantha; Truitt, Barbara; Iyengar, Sudha K; Klein, Ronald; Klein, Barbara E K; Duggal, Priya

2018-06-01

Nuclear cataract is the most common subtype of age-related cataract, the leading cause of blindness worldwide. It results from advanced nuclear sclerosis, or opacity in the center of the optic lens, and is affected by both genetic and environmental risk factors, including smoking. We sought to understand the genetic factors associated with nuclear sclerosis through interrogation of rare and low frequency coding variants using exome array data. We analyzed Illumina Human Exome Array data for 1,488 participants of European ancestry in the Beaver Dam Eye Study who were without cataract surgery for association with nuclear sclerosis grade, controlling for age and sex. We performed single-variant regression analysis for 32,138 variants with minor allele frequency (MAF) ≥0.003. In addition, gene-based analysis of 11,844 genes containing at least two variants with MAF nuclear sclerosis, the possible association with the RNF149 gene highlights a potential candidate gene for future studies that aim to understand the genetic architecture of nuclear sclerosis.

Enthalpy - entropy compensation effect in grain boundary phenomena

Czech Academy of Sciences Publication Activity Database

Lejček, Pavel

2005-01-01

Roč. 96, č. 10 (2005), s. 1129-1133 ISSN 0044-3093 R&D Projects: GA MPO(CZ) FF-P2/053 Institutional research plan: CEZ:AV0Z10100520 Keywords : compensation effect * enthalpy * entropy * thermodynamics * grain boundary Subject RIV: BJ - Thermodynamics Impact factor: 0.842, year: 2005

Improvements in analysis techniques for segmented mirror arrays

Science.gov (United States)

Michels, Gregory J.; Genberg, Victor L.; Bisson, Gary R.

2016-08-01

The employment of actively controlled segmented mirror architectures has become increasingly common in the development of current astronomical telescopes. Optomechanical analysis of such hardware presents unique issues compared to that of monolithic mirror designs. The work presented here is a review of current capabilities and improvements in the methodology of the analysis of mechanically induced surface deformation of such systems. The recent improvements include capability to differentiate surface deformation at the array and segment level. This differentiation allowing surface deformation analysis at each individual segment level offers useful insight into the mechanical behavior of the segments that is unavailable by analysis solely at the parent array level. In addition, capability to characterize the full displacement vector deformation of collections of points allows analysis of mechanical disturbance predictions of assembly interfaces relative to other assembly interfaces. This capability, called racking analysis, allows engineers to develop designs for segment-to-segment phasing performance in assembly integration, 0g release, and thermal stability of operation. The performance predicted by racking has the advantage of being comparable to the measurements used in assembly of hardware. Approaches to all of the above issues are presented and demonstrated by example with SigFit, a commercially available tool integrating mechanical analysis with optical analysis.

Standard molar enthalpies of formation of copper(II) {beta}-diketonates and monothio-{beta}-diketonates

Energy Technology Data Exchange (ETDEWEB)

Ribeiro da Silva, Manuel A.V. [Centro de Investigacao em Quimica, Departamento de Quimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)]. E-mail: risilva@fc.up.pt; Santos, Luis M.N.B.F. [Centro de Investigacao em Quimica, Departamento de Quimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)

2006-07-15

The standard (p{sup o}=0.1MPa) molar enthalpies of formation of the crystalline complexes of dibenzoylmethane (Hdbm), thenoyltrifluoroacetone (Httfa), monothiodibenzoylmethane (HdbmS), and monothiothenoyltrifluoroacetone (HttfaS) of copper(II) were determined, at T=298.15K, by high precision solution-reaction calorimetry. The standard molar enthalpies of sublimation of the copper(II) {beta}-diketonate complexes were measured by high-temperature Calvet microcalorimetry. From the standard molar enthalpies of formation of the complexes in the gaseous state, the mean molar dissociation enthalpies copper(II)-ligand, (Cu-L), were derived. {delta}{sub f}H{sub m}{sup o} (cr){delta}{sub cr}{sup g}H{sub m}{sup o} kJ.mol{sup -1}kJ.mol{sup -1}Bis(dibenzoylmethanate)copper(II), Cu(dbm){sub 2}-364.0+/-3.9230.7+/-8.2Bis(thenoyltrifluoroacetonate)copper(II), Cu(ttfa){sub 2}-1824.3+/-8.3167.9+/-7.4Bis(monothiodibenzoylmethanate)copper(II), Cu(dbmS){sub 2}35.6+/-7.7[241+/-15]Bis(monothiothenoyltrifluoroacetonate) copper(II), Cu(ttfaS){sub 2}-1405.7+/-8.3[177+/-15].

Enthalpies of mixing in the ternary system aluminium chloride - potassium chloride - aluminium chloride monoamine

Energy Technology Data Exchange (ETDEWEB)

Hatem, G.; Gaune-Escard, M.; Bros, J.P. (Aix-Marseille-2 Univ., 13 - Marseille (France). Centre de Saint Jerome); Ostvold, T. (Norges Tekniske Hoegskole, Trondheim (Norway). Inst. for Uorganisk Kjemi)

1988-06-01

Quasi binary enthalpy of mixing experiments have been performed in the ternary liquid system AlCl{sub 3}-AlCl{sub 3}NH{sub 3}-KCl by mixing AlCl{sub 3} + KCl with AlCl{sub 3}NH{sub 3} keeping the ratio X{sub AlCl3}/X{sub KCl} = 1.125, 1.5 and 2.0, respectively. At X{sub AlCl3}NH{sub 3} = 0.5 and T = 270deg C the enthalpies of mixing were {approx equal} -430 J mol{sup -1} for all the quasi-binaries studied. The new enthalpy data are not fully consistent with published vapour pressure data and thermodynamic model calculations. (orig.).

Determination of standard molar enthalpies of formation of SrMoO4 micro/nano structures

International Nuclear Information System (INIS)

Guo, Yunxiao; Fan, Gaochao; Huang, Zaiyin; Sun, Jilong; Wang, Lude; Wang, Tenghui; Chen, Jie

2012-01-01

Graphical abstract: Schematic illustration of thermochemical cycle between the nano and bulk reaction systems. Highlights: ► A thermochemical cycle was designed. ► Relationship of standard molar enthalpies of formation between micro/nano and bulk SrMoO 4 was gained. ► Microcalorimetry was used as a supplementary technology. ► Standard molar enthalpies of formation of the synthesized micro/nano SrMoO 4 were obtained. ► This novel approach can be used to other micro/nano materials. - Abstract: SrMoO 4 micro/nano structures were prepared by a simple reverse microemulsion method and were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscope (SEM). In order to associate standard molar enthalpies of formation of nano SrMoO 4 with bulk SrMoO 4 , the relationship of them was obtained through designing a thermochemical cycle according to thermodynamic potential function method. Combined with microcalorimetry, the standard molar enthalpies of formation of the synthesized micro/nano SrMoO 4 at 298.15 K were gained in this paper. And the variation of standard molar enthalpies of formation of micro/nano SrMoO 4 with different morphologies and sizes was discussed.

Modified solution calorimetry approach for determination of vaporization and sublimation enthalpies of branched-chain aliphatic and alkyl aromatic compounds at T = 298.15 K

International Nuclear Information System (INIS)

Varfolomeev, Mikhail A.; Novikov, Vladimir B.; Nagrimanov, Ruslan N.; Solomonov, Boris N.

2015-01-01

Highlights: • Solution enthalpies of 18 branching-chain alkyl aromatic and aliphatic compounds in cyclohexane were measured. • Group contributions to the enthalpy of solvation due to branching and substitution in carbon chain were evaluated. • Modified solution calorimetry based approach for determination of vaporization/sublimation enthalpies was proposed. • This approach provides vaporization/sublimation enthalpies directly at T = 298.15 K. • Vaporization/sublimation enthalpies of 35 branched-chain alkyl aromatic and aliphatic compounds were determined. - Abstract: The enthalpies of solution, solvation and vaporization/sublimation are interrelated values combined in the simplest thermodynamic circle. Hence, experimental determination of vaporization/sublimation enthalpy can be substituted by experimentally simpler determination of solution enthalpy when solvation enthalpy is known. Previously it was found that solvation enthalpies of a wide range of unbranched aliphatic and aromatic solutes in saturated hydrocarbons are in good linear correlation with their molar refraction values. This allows to estimate the vaporization/sublimation enthalpy of any unbranched organic compound from its solution enthalpy in saturated hydrocarbon and molar refraction. In the present work this approach was modified for determination of vaporization/sublimation enthalpy of branched-chain alkyl aromatic and aliphatic compounds. Group contributions to the enthalpy of solvation due to the branching of carbon chain were evaluated. Enthalpies of solution at infinite dilution of 18 branched-chain aliphatic and alkyl aromatic compounds were measured at T = 298.15 K. Vaporization/sublimation enthalpies for 35 branched aliphatic and alkyl aromatic compounds were determined by using modified solution calorimetry approach. These values are in good agreement with available literature data on vaporization/sublimation enthalpies obtained by conventional methods.

Kinetics and enthalpy of crystallization of uric acid dihydrate

International Nuclear Information System (INIS)

Sádovská, Galina; Honcová, Pavla; Sádovský, Zdeněk

2013-01-01

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 −3 NaCl and at thermodynamic and physiological temperature (25 and 37 °C) was studied using isoperibolic reaction twin calorimeter. The enthalpy of crystallization Δ cr H = −47.3 ± 0.9 and −46.2 ± 1.4 kJ mol −1 and kinetic constant k g = 2.0 × 10 −8 and 9.6 × 10 −8 m 4 s −1 mol −1 were determined at 25 and 37 °C, respectively

Standard molar enthalpies of formation of 1-methyl-2-piperidinemethanol, 1-piperidineethanol, and 2-piperidineethanol

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Cabral, Joana I.T.A.

2006-01-01

The standard (p o =0.1MPa) molar enthalpies of combustion, Δ c H m o , for the liquid compounds 1-methyl-2-piperidinemethanol, 1-piperidineethanol, and 2-piperidineethanol, were measured by static bomb calorimetry, in oxygen, at T=298.15K. The standard molar enthalpies of vaporization, at T=298.15K, of these three liquid compounds were determined by Calvet microcalorimetry. -Δ c H m o (l)/(kJ.mol -1 )Δ l g H m o /(kJ.mol -1 )1-Methyl-2-piperidinemethanol4598.3+/-1.868. 22+/-0.711-Piperidineethanol4595.2+/-1.764.18+/-0.812 -Piperidineethanol4566.2+/-1.375.24+/-0.52 These values, were used to derive the standard molar enthalpies of formation of the compounds, at T=298.15K, in their liquid and gaseous phase, respectively. The derived standard molar enthalpies of formation, in the gaseous state, are analyzed in terms of enthalpic increments and interpreted in terms of molecular structure.

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.

The mixing enthalpy of the Pb-Te system

International Nuclear Information System (INIS)

Blachnik, R.; Gather, B.

1983-01-01

The thermodynamic properties of molten Pb-Te alloys were measured at 1210 K in a Setaram-Calvet-type calorimeter. It was found that the enthalpy of mixing has a pronounced minimum of -26250 +- 950 J mol - 1 at 52 mol.%Te. The results obtained are discussed in terms of an ionic model. (Auth.)

Extension of the segment-based Wilson and NRTL models for correlation of excess molar enthalpies of polymer solutions

International Nuclear Information System (INIS)

Sadeghi, Rahmat

2005-01-01

The polymer Wilson model and the polymer NRTL model have been extended for the representation of the excess enthalpy of multicomponent polymer solutions. Applicability of obtained equations in the correlation of the excess enthalpies of polymer solutions has been examined. It is found that the both models are suitable models in representing the published excess enthalpy data for the tested polymer solutions

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.

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

International Nuclear Information System (INIS)

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 and northern part of the country, as well as in many of the Aegean Islands. The aim of this work is to review the options for managing wind load by using low-enthalpy geothermal energy for electricity (through heat pump utilisation) according to the local energy demand. -- Highlights: •Approximately 45.43 GWh per year of electricity can be covered from low-enthalpy geothermal energy resources (LEGERs). •In particular, 10% of the electricity demand can be covered from the LEGER N. Kessani (NK). •The needs for LEGER contribution were increased when wind turbine (WT) production was low. •In winter, where there is abundance of wind, LEGER can be used mostly for heating. •During summer, LEGER can assist more in electricity when heating is not needed

Data-flow Analysis of Programs with Associative Arrays

Directory of Open Access Journals (Sweden)

David Hauzar

2014-05-01

Full Text Available Dynamic programming languages, such as PHP, JavaScript, and Python, provide built-in data structures including associative arrays and objects with similar semantics—object properties can be created at run-time and accessed via arbitrary expressions. While a high level of security and safety of applications written in these languages can be of a particular importance (consider a web application storing sensitive data and providing its functionality worldwide, dynamic data structures pose significant challenges for data-flow analysis making traditional static verification methods both unsound and imprecise. In this paper, we propose a sound and precise approach for value and points-to analysis of programs with associative arrays-like data structures, upon which data-flow analyses can be built. We implemented our approach in a web-application domain—in an analyzer of PHP code.

The On-Site Analysis of the Cherenkov Telescope Array

CERN Document Server

Bulgarelli, Andrea; Zoli, Andrea; Aboudan, Alessio; Rodríguez-Vázquez, Juan José; De Cesare, Giovanni; De Rosa, Adriano; Maier, Gernot; Lyard, Etienne; Bastieri, Denis; Lombardi, Saverio; Tosti, Gino; Bergamaschi, Sonia; Beneventano, Domenico; Lamanna, Giovanni; Jacquemier, Jean; Kosack, Karl; Antonelli, Lucio Angelo; Boisson, Catherine; Borkowski, Jerzy; Buson, Sara; Carosi, Alessandro; Conforti, Vito; Colomé, Pep; Reyes, Raquel de los; Dumm, Jon; Evans, Phil; Fortson, Lucy; Fuessling, Matthias; Gotz, Diego; Graciani, Ricardo; Gianotti, Fulvio; Grandi, Paola; Hinton, Jim; Humensky, Brian; Inoue, Susumu; Knödlseder, Jürgen; Flour, Thierry Le; Lindemann, Rico; Malaguti, Giuseppe; Markoff, Sera; Marisaldi, Martino; Neyroud, Nadine; Nicastro, Luciano; Ohm, Stefan; Osborne, Julian; Oya, Igor; Rodriguez, Jerome; Rosen, Simon; Ribo, Marc; Tacchini, Alessandro; Schüssler, Fabian; Stolarczyk, Thierry; Torresi, Eleonora; Testa, Vincenzo; Wegner, Peter

2015-01-01

The Cherenkov Telescope Array (CTA) observatory will be one of the largest ground-based very high-energy gamma-ray observatories. The On-Site Analysis will be the first CTA scientific analysis of data acquired from the array of telescopes, in both northern and southern sites. The On-Site Analysis will have two pipelines: the Level-A pipeline (also known as Real-Time Analysis, RTA) and the level-B one. The RTA performs data quality monitoring and must be able to issue automated alerts on variable and transient astrophysical sources within 30 seconds from the last acquired Cherenkov event that contributes to the alert, with a sensitivity not worse than the one achieved by the final pipeline by more than a factor of 3. The Level-B Analysis has a better sensitivity (not be worse than the final one by a factor of 2) and the results should be available within 10 hours from the acquisition of the data: for this reason this analysis could be performed at the end of an observation or next morning. The latency (in part...

Standard molar enthalpies of formation of nickel(II) {beta}-diketonates and monothio-{beta}-diketonates

Energy Technology Data Exchange (ETDEWEB)

Ribeiro da Silva, Manuel A.V. [Centro de Investigacao em Quimica, Departamento de Quimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal)]. E-mail: risilva@fc.up.pt; Santos, Luis M.N.B.F. [Centro de Investigacao em Quimica, Departamento de Quimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Giera, Edward [Faculty of Chemistry, Wroclaw University, ul. F. Joliot-Curie 14, 50-383 Wroclaw (Poland)

2007-03-15

The standard (p{sup o}=0.1MPa) molar enthalpies of formation of the crystalline diaquobis(dibenzoylmethanate)nickel(II), Ni(dbm){sub 2}(H{sub 2}O){sub 2}, diaquobis(thenoyltrifluoroacetonate)nickel(II), Ni(ttfa){sub 2}(H{sub 2}O){sub 2} bis(monothiodibenzoylmethanate)nickel(II), Ni(dbmS){sub 2} and bis(monothiothenoyltrifluoroacetonate)nickel(II), Ni(HttfaS){sub 2} were determined, at T=298.15K, by high precision solution-reaction calorimetry. The standard molar enthalpy of sublimation of the monothiothenoyltrifluoroacetone (HttfaS) complex was measured by high-temperature Calvet microcalorimetry. From the standard molar enthalpies of formation of the complexes in the gaseous state, the mean nickel(II)-ligand molar dissociation enthalpies, (Ni-L), were derived. {delta}{sub f}H{sub m}{sup o}(cr)/(kJ.mol{sup -1})Diaquobis(dibenzoylmethanate)nickel(II), Ni(dbm){sub 2}(H{sub 2}O){sub 2}-993.3+/-3.8Diaquobis(thenoyltrifluoroacetonate)nickel(II), Ni(ttfa){sub 2}(H{sub 2}O){sub 2}-2452.0+/-8.3Bis(monothiodibenzoylmethanate)nickel(II), Ni(dbmS){sub 2}-42.1+/-5.9Bis(monothiothenoyltrifluoroacetonate)nickel(II), Ni(ttfaS){sub 2}-1473.5+/-8.1.

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.

Vapour pressures and enthalpies of vapourization of a series of the linear aliphatic nitriles

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Verevkin, Sergey P.; Koutek, Bohumir; Doubsky, Jan

2005-01-01

Vapour pressures and the molar enthalpies of vapourization ΔlgHm-bar of the linear aliphatic nitriles C 7 -C 17 have been determined by the transpiration method. Kovat's indices of these compounds were measured by capillary gas-chromatography. A linear correlation of enthalpies of vapourization ΔlgHm-bar at T=298.15 K of the nitriles studied with the Kovats indices has been found

Examination of hydrogen-bonding interactions between dissolved solutes and alkylbenzene solvents based on Abraham model correlations derived from measured enthalpies of solvation

Energy Technology Data Exchange (ETDEWEB)

Varfolomeev, Mikhail A.; Rakipov, Ilnaz T. [Chemical Institute, 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)

2014-10-20

Highlights: • Enthalpies of solution measured for 48 solutes dissolved in mesitylene. • Enthalpies of solution measured for 81 solutes dissolved in p-xylene. • Abraham model correlations derived for enthalpies of solvation of solutes in mesitylene. • Abraham model correlations derived for enthalpies of solvation of solutes in p-xylene. • Hydrogen-bonding enthalpies reported for interactions of aromatic hydrocarbons with hydrogen-bond acidic solutes. - Abstract: Enthalpies of solution at infinite dilution of 48 organic solutes in mesitylene and 81 organic solutes in p-xylene were measured using isothermal solution calorimeter. Enthalpies of solvation for 92 organic vapors and gaseous solutes in mesitylene and for 130 gaseous compounds in p-xylene were determined from the experimental and literature data. Abraham model correlations are determined from the experimental enthalpy of solvation data. The derived correlations describe the experimental gas-to-mesitylene and gas-to-p-xylene solvation enthalpies to within average standard deviations of 1.87 kJ mol{sup −1} and 2.08 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 mesitylene and p-xylene were calculated based on the Abraham solvation equation. Obtained values are in good agreement with the results determined using conventional methods.

Measurement of the enthalpies of vaporization and sublimation of solids aromatic hydrocarbons by differential scanning calorimetry

International Nuclear Information System (INIS)

Rojas, Aaron; Orozco, Eulogio

2003-01-01

An experimental procedure is proposed for direct measurement of the heat involved in the vaporization of a solid organic compound above its normal melting temperature. This technique consists on the fusion of a solid aromatic hydrocarbon, which is then vaporized by a sudden decrease of the pressure. The direct register of heat flow as function of time by differential scanning calorimetry allows the quantifying of the enthalpy of vaporization of compounds such as phenanthrene, β-naphthol, pyrene, and anthracene. Enthalpies of vaporization were measured in an isothermal mode over a range of temperatures from 10 to 20 K above the melting temperatures of each compound, while enthalpies of fusion were determined from separate experiments performed in a scanning mode. Enthalpies of sublimation are computed from results of fusion and vaporization, and then compared with results from the literature, which currently are obtained by calorimetric or indirect techniques

Experimental and theoretical excess molar enthalpies of ternary and binary mixtures containing 2-Methoxy-2-Methylpropane, 1-propanol, heptane

International Nuclear Information System (INIS)

Mato, Marta M.; Cebreiro, Susana M.; Paz Andrade, María Inmaculada; Legido, José Luis

2013-01-01

Highlights: • Experimental enthalpies for the ternary system MTBE + propanol + heptane were measured. • No experimental ternary values were found in the currently available literature. • Experimental enthalpies for the binary system propanol + heptane were measured. • Excess molar enthalpies are positive over the whole range of composition. • The ternary contribution is also positive, and the representation is asymmetric. -- Abstract: Excess molar enthalpies, at the temperature of 298.15 K and atmospheric pressure, have been measured for the ternary system {x 1 2-Methoxy-2-Methylpropane (MTBE) + x 2 1-propanol + (1 − x 1 − x 2 ) heptane}, over the whole composition range. Also, experimental data of excess molar enthalpy for the involved binary mixture {x 1-propanol + (1 − x) heptane} at the 298.15 K and atmospheric pressure, are reported. We are not aware of any previous experimental measurement of excess enthalpy in the literature for the ternary system presented in this study. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The ternary contribution to the excess enthalpy was correlated with the equation due to Morris et al. (1975) [15], and the equation proposed by Myers–Scott (1963) [14] was used to fitted the experimental binary mixture measured in this work. Additionally, the experimental results are compared with the estimations obtained by applying the group contribution model of UNIFAC, in the versions of Larsen et al. (1987) [16] and Gmehling et al. (1993) [17]. Several empirical expressions for estimating ternary properties from binary results were also tested

A new method for the determination of vaporization enthalpies of ionic liquids at low temperatures.

Science.gov (United States)

Verevkin, Sergey P; Zaitsau, Dzmitry H; Emelyanenko, Vladimir N; Heintz, Andreas

2011-11-10

A new method for the determination of vaporization enthalpies of extremely low volatile ILs has been developed using a newly constructed quartz crystal microbalance (QCM) vacuum setup. Because of the very high sensitivity of the QCM it has been possible to reduce the average temperature of the vaporization studies by approximately 100 K in comparison to other conventional techniques. The physical basis of the evaluation procedure has been developed and test measurements have been performed with the common ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C(2)mim][NTf(2)] extending the range of measuring vaporization enthalpies down to 363 K. The results obtained for [C(2)mim][NTf(2)] have been tested for thermodynamic consistency by comparison with data already available at higher temperatures. Comparison of the temperature-dependent vaporization enthalpy data taken from the literature show only acceptable agreement with the heat capacity difference of -40 J K(-1) mol(-1). The method developed in this work opens also a new way to obtain reliable values of vaporization enthalpies of thermally unstable ionic liquids.

Vapor pressures and sublimation enthalpies of novel bicyclic heterocycle derivatives

International Nuclear Information System (INIS)

Blokhina, Svetlana V.; Ol’khovich, Marina V.; Sharapova, Angelica V.; Perlovich, German L.; Proshin, Alexey N.

2014-01-01

Highlights: • The vapor pressures of novel bicyclo-derivatives of amine were measured. • Thermodynamic functions of sublimation were calculated. • The influence of substituent structure and chemical nature on the vapor pressure was studied. -- Abstract: The vapor pressures of five novel bicyclic heterocycle derivatives were measured over the temperature 341.15 to 396.15 K using the transpiration method by means of an inert gas carrier. From these results the standard enthalpies and Gibbs free energies of sublimation at the temperature 298.15 K were calculated. The effects of alkyl- and chloro-substitutions on changes in the thermodynamic functions have been investigated. Quantitative structure–property relationship on the basis HYBOT physico-chemical descriptors for biologically active compounds have been developed to predict the sublimation enthalpies and Gibbs free energies of the compounds studied

Enthalpy-increment measurements for CsI(s) and Cs2CrO4(s) by high-temperature Calvet calorimetry

International Nuclear Information System (INIS)

Venugopal, V.; Agarwal, R.; Roy, K.N.; Prasad, R.; Sood, D.D.

1987-01-01

Molar thermodynamic properties of CsI(s) and Cs 2 Cr O 4 (s) have been evaluated by enthalpy-increment measurements, using a Calvet high-temperature calorimeter. Least squares analyses were performed on the enthalpy increment results. Data is presented in tabular form for the dependence of enthalpy increments on temperature, in the range 333 to 822 K, for both caesium compounds, along with the thermal properties of the compounds. Good agreement is found between the present data and previously reported results on reduced enthalpy increments of CsI(s) and Cs 2 CrO 4 (s). (U.K.)

Three-dimensional quantitative structure-property relationship (3D-QSPR) models for prediction of thermodynamic properties of polychlorinated biphenyls (PCBs): enthalpy of vaporization.

Science.gov (United States)

Puri, Swati; Chickos, James S; Welsh, William J

2002-01-01

Three-dimensional Quantitative Structure-Property Relationship (QSPR) models have been derived using Comparative Molecular Field Analysis (CoMFA) to correlate the vaporization enthalpies of a representative set of polychlorinated biphenyls (PCBs) at 298.15 K with their CoMFA-calculated physicochemical properties. Various alignment schemes, such as inertial, as is, and atom fit, were employed in this study. The CoMFA models were also developed using different partial charge formalisms, namely, electrostatic potential (ESP) charges and Gasteiger-Marsili (GM) charges. The most predictive model for vaporization enthalpy (Delta(vap)H(m)(298.15 K)), with atom fit alignment and Gasteiger-Marsili charges, yielded r2 values 0.852 (cross-validated) and 0.996 (conventional). The vaporization enthalpies of PCBs increased with the number of chlorine atoms and were found to be larger for the meta- and para-substituted isomers. This model was used to predict Delta(vap)H(m)(298.15 K) of the entire set of 209 PCB congeners.

A molecular dynamics study of ambient and high pressure phases of silica: structure and enthalpy variation with molar volume.

Science.gov (United States)

Rajappa, Chitra; Sringeri, S Bhuvaneshwari; Subramanian, Yashonath; Gopalakrishnan, J

2014-06-28

Extensive molecular dynamics studies of 13 different silica polymorphs are reported in the isothermal-isobaric ensemble with the Parrinello-Rahman variable shape simulation cell. The van Beest-Kramer-van Santen (BKS) potential is shown to predict lattice parameters for most phases within 2%-3% accuracy, as well as the relative stabilities of different polymorphs in agreement with experiment. Enthalpies of high-density polymorphs - CaCl2-type, α-PbO2-type, and pyrite-type - for which no experimental data are available as yet, are predicted here. Further, the calculated enthalpies exhibit two distinct regimes as a function of molar volume-for low and medium-density polymorphs, it is almost independent of volume, while for high-pressure phases a steep dependence is seen. A detailed analysis indicates that the increased short-range contributions to enthalpy in the high-density phases arise not only from an increased coordination number of silicon but also shorter Si-O bond lengths. Our results indicate that amorphous phases of silica exhibit better optimization of short-range interactions than crystalline phases at the same density while the magnitude of Coulombic contributions is lower in the amorphous phase.

CGHPRO – A comprehensive data analysis tool for array CGH

Directory of Open Access Journals (Sweden)

Lenzner Steffen

2005-04-01

Full Text Available Abstract Background Array CGH (Comparative Genomic Hybridisation is a molecular cytogenetic technique for the genome wide detection of chromosomal imbalances. It is based on the co-hybridisation of differentially labelled test and reference DNA onto arrays of genomic BAC clones, cDNAs or oligonucleotides, and after correction for various intervening variables, loss or gain in the test DNA can be indicated from spots showing aberrant signal intensity ratios. Now that this technique is no longer confined to highly specialized laboratories and is entering the realm of clinical application, there is a need for a user-friendly software package that facilitates estimates of DNA dosage from raw signal intensities obtained by array CGH experiments, and which does not depend on a sophisticated computational environment. Results We have developed a user-friendly and versatile tool for the normalization, visualization, breakpoint detection and comparative analysis of array-CGH data. CGHPRO is a stand-alone JAVA application that guides the user through the whole process of data analysis. The import option for image analysis data covers several data formats, but users can also customize their own data formats. Several graphical representation tools assist in the selection of the appropriate normalization method. Intensity ratios of each clone can be plotted in a size-dependent manner along the chromosome ideograms. The interactive graphical interface offers the chance to explore the characteristics of each clone, such as the involvement of the clones sequence in segmental duplications. Circular Binary Segmentation and unsupervised Hidden Markov Model algorithms facilitate objective detection of chromosomal breakpoints. The storage of all essential data in a back-end database allows the simultaneously comparative analysis of different cases. The various display options facilitate also the definition of shortest regions of overlap and simplify the

Isothermogravimetric determination of the enthalpies of vaporization of 1-alkyl-3-methylimidazolium ionic liquids.

Science.gov (United States)

Luo, Huimin; Baker, Gary A; Dai, Sheng

2008-08-21

Vaporization enthalpies for two series of ionic liquids (ILs) composed of 1- n-alkyl-3-methylimidazolium cations, [Imm1+] (m=2, 3, 4, 6, 8, or 10), paired with either the bis(trifluoromethanesulfonyl)amide, [Tf2N-], or the bis(perfluoroethylsulfonyl)amide anion, [beti-], were determined using a simple, convenient, and highly reproducible thermogravimetric approach, and from these values, Hildebrand solubility parameters were estimated. Our results reveal two interesting and unanticipated outcomes: (i) methylation at the C2 position of [Imm1+] affords a significantly higher vaporization enthalpy; (ii) in all cases, the [beti-] anion served to lower the enthalpy of vaporization relative to [Tf2N-]. The widespread availability of the apparatus required for these measurements coupled with the ease of automation suggests the broad potential of this methodology for determining this critical parameter in a multitude of ILs.

Analysis and Simulation of Multi-target Echo Signals from a Phased Array Radar

OpenAIRE

Jia Zhen; Zhou Rui

2017-01-01

The construction of digital radar simulation systems has been a research hotspot of the radar field. This paper focuses on theoretical analysis and simulation of multi-target echo signals produced in a phased array radar system, and constructs an array antenna element and a signal generation environment. The antenna element is able to simulate planar arrays and optimizes these arrays by adding window functions. And the signal environment can model and simulate radar transmission signals, rada...

Enthalpy of formation of vanadates of iron, chromium, and aluminum

Energy Technology Data Exchange (ETDEWEB)

Kesler, Y.A.; Cheshnitskii, S.M.; Fotiev, A.A.; Tret' yakov, Y.D.

1985-09-01

The study of vanadates of iron, aluminum and chromium is of importance for the analysis of the functioning of catalysts of organic synthesis reactions and for the study of vanadium corrosion of structural materials. Of principal interest, however, are the processes in the treatment of vanadium-containing metallurgical slags and waste from thermal power plants, in which these compounds play a major role. At the same time, the thermochemical properties of these substances, which are necessary for creating the physicochemical foundations of industrially important processes, have not been investigated sufficiently. The authors therefore undertake here a study of the compounds FeVO/sub 4/, AIVO/sub 4/, CrVO/sub 4/ and FeCr(VO/sub 4/)/sub 2/, to determine their enthalpies of formation.

Influence of tribomechanical micronization and hydrocolloids addition on enthalpy and apparent specific heat of whey protein model solutions

Directory of Open Access Journals (Sweden)

Zoran Herceg

2002-01-01

Full Text Available Knowledge of thermophysical properties, especially the phase transitions temperature, specific heat and enthalpy, are essential in defining the freezing process parameters as well as storage conditions of frozen food. In this work thermophysical properties of 10% model solutions prepared with 60% whey protein concentrate (WPC with various hydrocolloids addition (HVEP, YO-EH, YO-L i YO-M were investigated. Powdered whey protein concentrate was treated in equipment for tribomechanical micronization and activation at 40000 rpm (Patent: PCT/1B99/00757 just before model solutions preparation. Particle size analysis was performed using Frich –laser particle sizer “analysette 22”. The phase transition temperatures were determined by differential thermal analysis (DTA, while specific heat and enthalpy were calculated according to several mathematical equations. The results have shown that, due to tribomechanical treatment, certain changes in thermophysical and energetic properties of materials occurred. Tribomechanical treatment affects changes in granulometrical composition of WPC which result in higher abilities of reactions with hydrocolloids in model solutions and significant changes in thermophysical properties of the mentioned models.

Vapor pressures and enthalpies of vaporization of a series of γ and δ-lactones by correlation gas chromatography

International Nuclear Information System (INIS)

Kozlovskiy, Mikhail; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpies of γ-octanolactone, γ- and δ-undecanolactone and γ and δ-dodecanolactone are reported. • Equations for predicting the vapor pressures over the temperature range T = (298.15 to 350) K are provided. • Vaporization enthalpies are compared to predicted values. - Abstract: The vaporization enthalpies of γ-octanolactone, γ- and δ-undecanolactone and γ and δ-dodecanolactone used commercially as flavor ingredients are reported as are their vapor pressures over the temperature range T = (298.15 to 350) K. Vaporization enthalpies at T = 298.15 K of: (66.0 ± 3.9), (79.4 ± 4.4), (80.1 ± 4.5), (83.9 ± 4.6), and (84.61 ± 4.7) kJ · mol −1 and vapor pressures also at T = 298.15 K of: (2.8 ± 0.9), (0.12 ± 0.05), (0.09 ± 0.04), (0.04 ± 0.02), and (0.03 ± 0.02) Pa, respectively, have been evaluated by correlation gas chromatography experiments. The vaporization enthalpies of the lactones studied are reproduced within ±0.5 kJ · mol −1 using a group additivity scheme reported previously for γ- and δ-lactones. The vaporization enthalpies of the γ- and δ-lactones are compared to a similar series of ω-lactones

Enthalpies of formation of 5,6-dihydro-5-methyluracil and 5,6-dihydro-6-methyluracil

International Nuclear Information System (INIS)

Amaral, Luísa M.P.F.; Szterner, Piotr; Ribeiro da Silva, Manuel A.V.

2013-01-01

Highlights: • Δ c H m ° of two methyl-5,6-dihydrouracils have been determined by combustion calorimetry. • Vapor pressures were measured by the Knudsen effusion technique. • Gas phase enthalpies of formation of methyl-5,6-dihydrouracils, have been derived. -- Abstract: The standard (p° = 0.1 MPa) molar enthalpy of combustion, Δ c H m ° , of two crystalline compounds, 5,6-dihydro-5-methyluracil and 5,6-dihydro-6-methyluracil, were determined, at T = 298.15 K, using a static bomb combustion calorimeter. The vapor pressures as a function of the temperature were measured for those compounds, by the Knudsen effusion technique, and the standard molar enthalpies of sublimation at the mean temperature of the vapor pressure measurements were derived from the Clausius–Clapeyron equation, and corrected to T = 298.15 K using an estimated value for Δ cr g C p,m ° . These values were used to derive the standard molar enthalpies of formation of the two compounds studied, in the condensed and gaseous phases. Some considerations about the relative stability of the two isomers were made and compared with similar compounds

RoboSCell: An automated single cell arraying and analysis instrument

KAUST Repository

Sakaki, Kelly

2009-09-09

Single cell research has the potential to revolutionize experimental methods in biomedical sciences and contribute to clinical practices. Recent studies suggest analysis of single cells reveals novel features of intracellular processes, cell-to-cell interactions and cell structure. The methods of single cell analysis require mechanical resolution and accuracy that is not possible using conventional techniques. Robotic instruments and novel microdevices can achieve higher throughput and repeatability; however, the development of such instrumentation is a formidable task. A void exists in the state-of-the-art for automated analysis of single cells. With the increase in interest in single cell analyses in stem cell and cancer research the ability to facilitate higher throughput and repeatable procedures is necessary. In this paper, a high-throughput, single cell microarray-based robotic instrument, called the RoboSCell, is described. The proposed instrument employs a partially transparent single cell microarray (SCM) integrated with a robotic biomanipulator for in vitro analyses of live single cells trapped at the array sites. Cells, labeled with immunomagnetic particles, are captured at the array sites by channeling magnetic fields through encapsulated permalloy channels in the SCM. The RoboSCell is capable of systematically scanning the captured cells temporarily immobilized at the array sites and using optical methods to repeatedly measure extracellular and intracellular characteristics over time. The instrument\\'s capabilities are demonstrated by arraying human T lymphocytes and measuring the uptake dynamics of calcein acetoxymethylester-all in a fully automated fashion. © 2009 Springer Science+Business Media, LLC.

Analysis of the modal behavior of an antiguide diode laser array with Talbot filter

NARCIS (Netherlands)

van Eijk, P.D.; van Eijk, Pieter D.; Reglat, Muriel; Vassilief, Georges; Krijnen, Gijsbertus J.M.; Driessen, A.; Mouthaan, A.J.

An analysis of the filtering of the array modes in a resonant optical waveguide (ROW) array of antiguides by a diffractive spatial filter (a Talbot filter) is presented. A dispersion relation is derived for the array modes, allowing the calculation of the field distribution. The filtering is

Temperature dependences of saturated vapor pressure and the enthalpy of vaporization of n-pentyl esters of dicarboxylic acids

Science.gov (United States)

Portnova, S. V.; Krasnykh, E. L.; Levanova, S. V.

2016-05-01

The saturated vapor pressures and enthalpies of vaporization of n-pentyl esters of linear C2-C6 dicarboxylic acids are determined by the transpiration method in the temperature range of 309.2-361.2 K. The dependences of enthalpies of vaporization on the number of carbon atoms in the molecule and on the retention indices have been determined. The predictive capabilities of the existing calculation schemes for estimation of enthalpy of vaporization of the studied compounds have been analyzed.

Dependence of enthalpies of dissolution of β-alanyl-β-alanine on the composition of (water + alcohol) mixtures at 298.15 K

International Nuclear Information System (INIS)

Smirnov, Valeriy I.; Badelin, Valentin G.

2011-01-01

Highlights: · Enthalpies of dissolution of β-alanyl-β-alanine are measured in aqueous methanol, ethanol, 1-propanol and 2-propanol by calorimetry. · Standard values of dissolution and transfer enthalpies of β-alanyl-β-alanine and enthalpy coefficients of pair-wise interactions are calculated. · Dependences of the thermodynamic characteristics of dissolution of β-alanyl-β-alanine on the composition of (water + alcohol) mixtures are determined. - Abstract: The dissolution enthalpies of β-alanyl-β-alanine in aqueous methanol, ethanol, 1-propanol and 2-propanol solutions with an alcohol content up to 0.4 mole fractions have been measured calorimetrically at T = 298.15 K. The standard enthalpies of dissolution, Δ sol H o and transfer, Δ tr H o , of β-alanyl-β-alanine from water into mixed solvents and the enthalpy coefficients of pair-wise interactions, h xy , of β-alanyl-β-alanine with alcohol solvent molecules have been calculated. The results are discussed in terms of solute-solute and solute-solvent interactions.

Group vector space method for estimating enthalpy of vaporization of organic compounds at the normal boiling point.

Science.gov (United States)

Wenying, Wei; Jinyu, Han; Wen, Xu

2004-01-01

The specific position of a group in the molecule has been considered, and a group vector space method for estimating enthalpy of vaporization at the normal boiling point of organic compounds has been developed. Expression for enthalpy of vaporization Delta(vap)H(T(b)) has been established and numerical values of relative group parameters obtained. The average percent deviation of estimation of Delta(vap)H(T(b)) is 1.16, which show that the present method demonstrates significant improvement in applicability to predict the enthalpy of vaporization at the normal boiling point, compared the conventional group methods.

Structural studies of cyclic ureas: 3. Enthalpy of formation of barbital

International Nuclear Information System (INIS)

Ribeiro da Silva, Maria das Dores M.C.; Ribeiro da Silva, Manuel A.V.; Freitas, Vera L.S.; Roux, Maria Victoria; Jimenez, Pilar; Temprado, Manuel; Davalos, Juan Z.; Cabildo, Pilar; Claramunt, Rosa M.; Elguero, Jose

2009-01-01

A thermochemical and thermophysical study has been carried out for crystalline barbital [5,5'-diethylbarbituric acid]. The thermochemical study was made by static bomb combustion calorimetry, from which the standard (p 0 =0.1MPa) molar enthalpy of formation of the crystalline barbital, at T = 298.15 K, was derived as -(753.0 ± 1.8) kJ . mol -1 . The thermophysical study was made by differential scanning calorimetry over the temperature interval (265 to 470) K. A solid-solid phase transition was found at T = 413.3 K. The vapour pressures of the crystalline barbital were measured at several temperatures between T = (355 and 377) K, by the Knudsen mass-loss effusion technique, from which the standard molar enthalpy of sublimation, at T = 298.15 K was derived as (117.3 ± 0.6) kJ . mol -1 . The combination of the experimental results yielded the standard molar enthalpy of formation of barbital in the gaseous phase, at T = 298.15 K, as -(635.8 ± 1.9) kJ . mol -1 . This value is compared and discussed with our theoretical calculations by several methods (Gaussian-n theories G2 and G3, complete basis set CBS-QB3, density functional B3P86 and B3LYP) by means of atomization and isodesmic reaction schemes.

Read margin analysis of crossbar arrays using the cell-variability-aware simulation method

Science.gov (United States)

Sun, Wookyung; Choi, Sujin; Shin, Hyungsoon

2018-02-01

This paper proposes a new concept of read margin analysis of crossbar arrays using cell-variability-aware simulation. The size of the crossbar array should be considered to predict the read margin characteristic of the crossbar array because the read margin depends on the number of word lines and bit lines. However, an excessively high-CPU time is required to simulate large arrays using a commercial circuit simulator. A variability-aware MATLAB simulator that considers independent variability sources is developed to analyze the characteristics of the read margin according to the array size. The developed MATLAB simulator provides an effective method for reducing the simulation time while maintaining the accuracy of the read margin estimation in the crossbar array. The simulation is also highly efficient in analyzing the characteristic of the crossbar memory array considering the statistical variations in the cell characteristics.

Solar array deployment analysis considering path-dependent behavior of a tape spring hinge

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyung Won; Park, Young Jin [KAIST, Daejeon (Korea, Republic of)

2015-05-15

Solar array deployment analysis is conducted considering the path-dependent nonlinear behavior of tape spring hinge. Such hinges offer many advantages over rigid hinges; they are self-deployable, self-locking, lightweight, and simple. However, they show strongly nonlinear behavior with respect to rotation angle, making deployment analysis difficult. To accurately consider the characteristics of tape spring hinges for deployment analysis, a path-dependent path identification (PI) method for tracing the previous path of the moment is introduced. To analyze the deployment motion, the governing equation for solar array deployment is derived within the framework of Kane's dynamic equation for three deployable solar panels. The numerical solution is compared with the Recurdyn's multi-body dynamics analysis solution using experimentally measured moment-rotation profiles. Solar array deployment analysis is conducted by considering and not considering the path-dependent PI method. This simulation example shows that the proposed path-dependent PI method is very effective for accurately predicting the deployment motion.

Molar volume, excess enthalpy, and Prigogine-Defay ratio of some silicate glasses with different (P,T) histories.

Science.gov (United States)

Wondraczek, Lothar; Behrens, Harald

2007-10-21

Structural relaxation in silicate glasses with different (p,T) histories was experimentally examined by differential scanning calorimetry and measurements of molar volume under ambient pressure. Temperature and pressure-dependent rates of changes in molar volume and generation of excess enthalpy were determined for sodium trisilicate, soda lime silicate, and sodium borosilicate (NBS) compositions. From the derived data, Prigogine-Defay ratios are calculated and discussed. Changes of excess enthalpy are governed mainly by changes in short-range structure, as is shown for NBS where boron coordination is highly sensitive to pressure. For all three glasses, it is shown how the relaxation functions that underlie volume, enthalpy, and structural relaxation decouple for changes in cooling rates and pressure of freezing, respectively. The magnitude of the divergence between enthalpy and volume may be related to differences in structural sensitivity to changes in the (p,V,T,t) space on different length scales. The findings suggest that the Prigogine-Defay ratio is related to the magnitude of the discussed decoupling effect.

Enthalpy of Vaporization and Vapor Pressures: An Inexpensive Apparatus

Science.gov (United States)

Battino, Rubin; Dolson, David A.; Hall, Michael A.; Letcher, Trevor M.

2007-01-01

A simple and inexpensive method to determine the enthalpy of vaporization of liquids by measuring vapor pressure as a function of temperature is described. The vapor pressures measured with the stopcock cell were higher than the literature values and those measured with the sidearm rubber septum cell were both higher and lower than literature…

Enthalpy and the mechanics of AdS black holes

International Nuclear Information System (INIS)

Kastor, David; Traschen, Jennie; Ray, Sourya

2009-01-01

We present geometric derivations of the Smarr formula for static AdS black holes and an expanded first law that includes variations in the cosmological constant. These two results are further related by a scaling argument based on Euler's theorem. The key new ingredient in the constructions is a two-form potential for the static Killing field. Surface integrals of the Killing potential determine the coefficient of the variation of Λ in the first law. This coefficient is proportional to a finite, effective volume for the region outside the AdS black hole horizon, which can also be interpreted as minus the volume excluded from a spatial slice by the black hole horizon. This effective volume also contributes to the Smarr formula. Since Λ is naturally thought of as a pressure, the new term in the first law has the form of effective volume times change in pressure that arises in the variation of the enthalpy in classical thermodynamics. This and related arguments suggest that the mass of an AdS black hole should be interpreted as the enthalpy of the spacetime.

Direct measurements of the enthalpy of solution of solid solute in supercritical fluids: study on the CO2-naphthalene system.

Science.gov (United States)

Zhang, X; Han, B; Zhang, J; Li, H; He, J; Yan, H

2001-10-01

A setup for a calorimeter for simultaneously measuring the solubility and the solution enthalpy of solid solutes in supercritical fluids (SCFs) has been established. The enthalpy of solution of naphthalene in supercritical CO2 was measured at 308.15 K in the pressure range from 8.0-11.0 MPa. It was found that the enthalpy of solution (deltaH) was negative in the pressure range from 8.0 to 9.5 MPa, and the absolute value decreased with increasing pressure. In this pressure range, the dissolution of the solute was enthalpy driven. However, the deltaH became positive at pressures higher than 9.5 MPa, and the dissolution was entropy driven. Monte Carlo simulation was performed to analyze the local structural environment of the solvated naphthalene molecules in supercritical CO2 under the experimental conditions for the calorimetric measurements. By combining the enthalpy data and the simulation results, it can be deduced that the energy level of CO2 in the high compressible region is higher than that at higher pressures, which results in the large negative enthalpy of solution and the larger degree of solvent-solute clustering in the high compressible region.

Enthalpy increment measurements of Sr3Zr2O7(s) and Sr4Zr3O10(s)

International Nuclear Information System (INIS)

Banerjee, A.; Dash, S.; Prasad, R.; Venugopal, V.

1998-01-01

Enthalpy increment measurements on Sr 3 Zr 2 O 7 (s) and Sr 4 Zr 3 O 10 (s) were carried out using a Calvet micro-calorimeter. The enthalpy increment values were least squares analyzed with the constraints that H 0 (T)-H 0 (298.15 K) at 298.15 K equals to zero and C p 0 (298.15 K) equals to the estimated value. The dependence of enthalpy increment with temperature is given. (orig.)

Predicting permeability of low enthalpy geothermal reservoirs: A case study from the Upper Triassic − Lower Jurassic Gassum Formation, Norwegian–Danish Basin

DEFF Research Database (Denmark)

Weibel, Rikke; Olivarius, Mette; Kristensen, Lars

2017-01-01

This paper aims at improving the predictability of permeability in low enthalpy geothermal reser-voirs by investigating the effect of diagenesis on sandstone permeability. Applying the best fittedporosity–permeability trend lines, obtained from conventional core analysis, to log-interpreted poros...

SNP Arrays

Directory of Open Access Journals (Sweden)

Jari Louhelainen

2016-10-01

Full Text Available The papers published in this Special Issue “SNP arrays” (Single Nucleotide Polymorphism Arrays focus on several perspectives associated with arrays of this type. The range of papers vary from a case report to reviews, thereby targeting wider audiences working in this field. The research focus of SNP arrays is often human cancers but this Issue expands that focus to include areas such as rare conditions, animal breeding and bioinformatics tools. Given the limited scope, the spectrum of papers is nothing short of remarkable and even from a technical point of view these papers will contribute to the field at a general level. Three of the papers published in this Special Issue focus on the use of various SNP array approaches in the analysis of three different cancer types. Two of the papers concentrate on two very different rare conditions, applying the SNP arrays slightly differently. Finally, two other papers evaluate the use of the SNP arrays in the context of genetic analysis of livestock. The findings reported in these papers help to close gaps in the current literature and also to give guidelines for future applications of SNP arrays.

Standard formation enthalpies of Nasub(2+x)Vsub(6)Osub(16-y) bronze of kappa type

International Nuclear Information System (INIS)

Khodos, M.Ya.; Slobodin, B.V.; Surat, L.L.; Fotiev, A.A.

1980-01-01

Standard formation enthalpies of sodium oxide vanadium bronze of kappa Nasub(2+x)Vsub(6)Osub(16-y) type of different composition have been determined by the method of solution calorimetry. It has been ascertained that within the limits of homogeneity a standard formation enthalpy decreases insignificantly with the increase of bronze oxygen defectiveness and is a linear function of sodium content

Array analysis of regional Pn and Pg wavefields from the Nevada Test Site

International Nuclear Information System (INIS)

Leonard, M.A.

1991-06-01

Small-aperture high-frequency seismic arrays with dimensions of a few kilometers or less, can improve our ability to seismically monitor compliance with a low-yield Threshold Test Ban Treaty. This work studies the characteristics and effectiveness of array processing of the regional Pn and Pg wavefields generated by underground nuclear explosions at the Nevada Test Site. Waveform data from the explosion HARDIN (m b = 5.5) is recorded at a temporary 12-element, 3-component, 1.5 km-aperture array sited in an area of northern Nevada. The explosions VILLE (m b = 4.4) and SALUT (m b = 5.5) are recorded at two arrays sited in the Mojave desert, one a 96-element vertical-component 7 km-aperture array and the other a 155-element vertical-component 4 km-aperture array. Among the mean spectra for the m b = 5.5 events there are significant differences in low-frequency spectral amplitudes between array sites. The spectra become nearly identical beyond about 6 Hz. Spectral ratios are used to examine seismic source properties and the partitioning of energy between Pn and Pg. Frequency-wavenumber analysis at the 12-element array is used to obtain estimates of signal gain, phase velocity, and source azimuth. This analysis reveals frequency-dependent biases in velocity and azimuth of the coherent Pn and Pg arrivals. Signal correlation, the principal factor governing array performance, is examined in terms of spatial coherence estimates. The coherence is found to vary between the three sites. In all cases the coherence of Pn is greater than that for Pg. 81 refs., 92 figs., 5 tabs

Array analysis of regional Pn and Pg wavefields from the Nevada Test Site

Energy Technology Data Exchange (ETDEWEB)

Leonard, M.A. (California Univ., Berkeley, CA (United States). Dept. of Geology and Geophysics Lawrence Berkeley Lab., CA (United States))

1991-06-01

Small-aperture high-frequency seismic arrays with dimensions of a few kilometers or less, can improve our ability to seismically monitor compliance with a low-yield Threshold Test Ban Treaty. This work studies the characteristics and effectiveness of array processing of the regional Pn and Pg wavefields generated by underground nuclear explosions at the Nevada Test Site. Waveform data from the explosion HARDIN (m{sub b} = 5.5) is recorded at a temporary 12-element, 3-component, 1.5 km-aperture array sited in an area of northern Nevada. The explosions VILLE (m{sub b} = 4.4) and SALUT (m{sub b} = 5.5) are recorded at two arrays sited in the Mojave desert, one a 96-element vertical-component 7 km-aperture array and the other a 155-element vertical-component 4 km-aperture array. Among the mean spectra for the m{sub b} = 5.5 events there are significant differences in low-frequency spectral amplitudes between array sites. The spectra become nearly identical beyond about 6 Hz. Spectral ratios are used to examine seismic source properties and the partitioning of energy between Pn and Pg. Frequency-wavenumber analysis at the 12-element array is used to obtain estimates of signal gain, phase velocity, and source azimuth. This analysis reveals frequency-dependent biases in velocity and azimuth of the coherent Pn and Pg arrivals. Signal correlation, the principal factor governing array performance, is examined in terms of spatial coherence estimates. The coherence is found to vary between the three sites. In all cases the coherence of Pn is greater than that for Pg. 81 refs., 92 figs., 5 tabs.

Study on the relationship between water exergy and enthalpy applicable to the energetic analysis of steam thermodynamic cycles; Estudo da relacao entre exergia e entalpia da agua, aplicavel a analise energetica e exergetica de ciclos termodinamicos a vapor

Energy Technology Data Exchange (ETDEWEB)

Llagostera, Jorge [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mail: llagost@fem.unicamp.br

1995-07-01

This paper presents a thermodynamic relation, defined to improve methodologies in Second Law Analysis of thermal systems. This relation is defined dividing the specific thermomechanical exergy by the specific enthalpy of a substance, adopting as reference a selected thermodynamic state. This relation is determined and analyzed for liquid water and steam in a range of temperatures (30 deg C - 700 deg C) and pressures (0.101325 MPa - 18.1 Mpa). The behavior of the proposed relation is compared against the exergy behavior as function of temperature and pressure. The proposed relation can be used to compare and evaluate thermodynamic states that have similar exergy content. It makes possible to identify the states presenting higher exergetic level per enthalpy unit. This concept can be useful in thermodynamic analysis and optimization of steam cycles and thermal processes. (author)

Structure–property relationships in ionic liquids: Influence of branched and cyclic groups on vaporization enthalpies of imidazolium-based ILs

International Nuclear Information System (INIS)

Zaitsau, Dzmitry H.; Varfolomeev, Mikhail A.; Verevkin, Sergey P.; Stanton, Alexander D.; Hindman, Michelle S.; Bara, Jason E.

2016-01-01

Highlights: • Ionic liquids [Rmim][NTf_2] with iso-alkyl and cyclic substituents were synthesized. • Vaporization enthalpies were measured using quartz-crystal microbalance. • Data consistency was tested by comparison with the homomorph compounds. • Vaporization enthalpies of branched ILs are generally on the same level as for linear. • These findings are useful for the quick estimation of vaporization enthalpies. - Abstract: Ionic liquids (ILs) with branched and cyclic substituents are seldom studied in the literature, and as such there are little to no data characterizing their thermophysical properties. ILs with branched and cyclic substituents are just as convenient to synthesize and study as their counterparts with linear substituents, but the effects of these substituents on IL properties are not yet well-defined due to the preference for linear substituents. Standard molar vaporization enthalpies of six imidazolium based ionic liquids [Rmim][NTf_2] with iso-alkyl and cyclic substituents (R = iso-propyl, iso-butyl, sec-butyl, methylcyclopropyl, cyclopentyl and methylcyclohexyl) were derived from quartz-crystal microbalance (QCM) method. Enthalpies of vaporization measured at elevated temperatures have been adjusted to the reference temperature 298 K and tested for consistency by comparison with the homomorphy alkane, alkylbenzenes and alkyl-imidazoles. It was found that vaporization enthalpies of ILs with the iso-alkyl and cyclic groups are generally on the same level within (±2 to 3) kJ · mol"−"1 significantly compared to the analogous ILs with the imidazolium cation substituted with the linear alkyl substituents of the same chain length. These findings are useful for the quick estimation of vaporization enthalpies of various substituted IL cations (e.g. pyrrolidinium, ammonium, pyridinium, etc.).

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

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.

A study of the vaporization enthalpies of some 1-substituted imidazoles and pyrazoles by correlation-gas chromatography.

Science.gov (United States)

Lipkind, Dmitry; Plienrasri, Chatchawat; Chickos, James S

2010-12-23

The vaporization enthalpies of 1-methyl-, 1-ethyl-, 1-phenyl-, and 1-benzylimidazole, 1-methyl- and 1-phenylpyrazole, and trans-azobenzene are evaluated by correlation-gas chromatography (C-GC) using a variety of azines and diazines as standards. The vaporization enthalpies obtained by C-GC when compared to literature values are approximately 14 kJ·mol(-1) smaller for the imidazoles and 6 kJ·mol(-1) smaller for the pyrazoles. The literature vaporization enthalpies of 1-methylpyrrole and 1-methylindole, two closely related compounds with one less nitrogen, are reproduced by C-GC. These results suggest that the magnitude of the intermolecular interactions present in 1-substituted imidazoles and pyrazoles are significantly larger than the those present in the reference compounds and greater than or equal in magnitude to the enhanced intermolecular interactions observed previously in aromatic 1,2-diazines. The vaporization enthalpy and vapor pressure of a trans-1,2-diazine, trans-azobenzene, measured by C-GC using similar standards reproduced the literature values within experimental error.

Theory and design of compact hybrid microphone arrays on two-dimensional planes for three-dimensional soundfield analysis.

Science.gov (United States)

Chen, Hanchi; Abhayapala, Thushara D; Zhang, Wen

2015-11-01

Soundfield analysis based on spherical harmonic decomposition has been widely used in various applications; however, a drawback is the three-dimensional geometry of the microphone arrays. In this paper, a method to design two-dimensional planar microphone arrays that are capable of capturing three-dimensional (3D) spatial soundfields is proposed. Through the utilization of both omni-directional and first order microphones, the proposed microphone array is capable of measuring soundfield components that are undetectable to conventional planar omni-directional microphone arrays, thus providing the same functionality as 3D arrays designed for the same purpose. Simulations show that the accuracy of the planar microphone array is comparable to traditional spherical microphone arrays. Due to its compact shape, the proposed microphone array greatly increases the feasibility of 3D soundfield analysis techniques in real-world applications.

Heat Effect of the Protonation of Glycine and the Enthalpies of Resolvation of Participating Chemical Species in Water-Dimethylsulfoxide Solvent Mixtures

Science.gov (United States)

Isaeva, V. A.; Sharnin, V. A.

2018-02-01

Enthalpies of the protonation of glycine in water‒dimethylsulfoxide (DMSO) mixed solvents are determined calorimetrically in the range of DMSO mole fractions of 0.0 to 0.9, at T = 298.15 K and an ionic strength μ = 0.3 (NaClO4). It is established that the protonation of glycine becomes more exothermic with an increasing mole fraction of DMSO, and the enthalpies of resolvation of glycine and glycinium ions in water‒DMSO solvent mixtures are calculated. It is shown that the small changes in the enthalpy of protonation observed at low mole fractions of DMSO are caused by the contributions from the solvation of proton and protonated glycine cancelling each other out. The enthalpy term of the Gibbs energy of the reaction leading to the formation of glycinium ion is estimated along with the enthalpy of resolvation of the reacting species in the water‒DMSO mixed solvent.

Clearance Analysis of Node 3 Aft CBM to the Stowed FGB Solar Array

Science.gov (United States)

Liddle, Donn

2014-01-01

In early 2011, the ISS Vehicle Configuration Office began considering the relocation of the Permanent Multipurpose Module (PMM) to the aft facing Common Berthing Mechanism (CBM) on Node 3 to open a berthing location for visiting vehicles on the Node 1 nadir CBM. In this position, computer-aided design (CAD) models indicated that the aft end of the PMM would be only a few inches from the stowed Functional Cargo Block (FGB) port solar array. To validate the CAD model clearance analysis, in the late summer of 2011 the Image Science and Analysis Group (ISAG) was asked to determine the true geometric relationship between the on-orbit aft facing Node 3 CBM and the FGB port solar array. The desired measurements could be computed easily by photogrammetric analysis if current imagery of the ISS hardware were obtained. Beginning in the fall of 2011, ISAG used the Dynamic Onboard Ubiquitous Graphics (DOUG) program to design a way to acquire imagery of the aft face of Node 3, the aft end-cone of Node 1, the port side of pressurized mating adapter 1 (PMA1), and the port side of the FGB out to the tip of the port solar array using cameras on the Space Station Remote Manipulator System (SSRMS). This was complicated by the need to thread the SSRMS under the truss, past Node 3 and the Cupola, and into the space between the aft side of Node 3 and the FGB solar array to acquire more than 100 images from multiple positions. To minimize the number of SSRMS movements, the Special Purpose Dexterous Manipulator (SPDM) would be attached to the SSRMS. This would make it possible to park the SPDM in one position and acquire multiple images by changing the viewing orientation of the SPDM body cameras using the pan/tilt units on which the cameras are mounted. Using this implementation concept, ISAG identified four SSRMS/SPDM positions from which all of the needed imagery could be acquired. Based on a photogrammetric simulation, it was estimated that the location of the FGB solar array could be

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

International Nuclear Information System (INIS)

Venaelaeinen, A.; Saku, S.; Jylhae, K.; Nikulin, G.; Kjellstroem, E.; Baerring, L.

2009-06-01

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

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

Standard enthalpies of formation of selected Ru{sub 2}YZ Heusler compounds

Energy Technology Data Exchange (ETDEWEB)

Yin, Ming, E-mail: myin1@hawk.iit.edu; Nash, Philip

2015-06-15

Highlights: • Standard enthalpies of formation of Ru{sub 2}YZ were measured using a drop calorimeter. • Result of L2{sub 1} structured compounds agrees with first principles data. • Lattice parameters and related phase relationships were consistent with literature data. • Ru{sub 2}HfSn, Ru{sub 2}TiSn, Ru{sub 2}VGa, Ru{sub 2}VSi, Ru{sub 2}VSn of L2{sub 1} structure were reported for the first time. - Abstract: The standard enthalpies of formation of selected ternary Ru-based Heusler compounds Ru{sub 2}YZ (Y = Fe, Hf, Mn, Ti, V; Z = Al, Ga, In, Si, Ge, Sn) were measured using high temperature direct reaction calorimetry. The measured enthalpies of formation (in kJ/mole of atoms) of the Heusler compounds are, Ru{sub 2}FeGe (−19.7 ± 3.3); Ru{sub 2}HfSn (−24.9 ± 3.6); Ru{sub 2}MnSi (−46.0 ± 2.6); Ru{sub 2}MnGe (−29.7 ± 1.0); Ru{sub 2}MnSn (−20.6 ± 2.4); Ru{sub 2}TiSi (−94.9 ± 4.0); Ru{sub 2}TiGe (−79.1 ± 3.2); Ru{sub 2}TiSn (−60.6 ± 1.8); Ru{sub 2}VSi (−55.9 ± 1.7);for the B2-structured compounds, Ru{sub 2}FeSi (−28.5 ± 0.8); Ru{sub 2}HfAl (−70.8 ± 1.9); Ru{sub 2}MnAl (−32.3 ± 1.9); Ru{sub 2}MnGa (−25.3 ± 3.0); Ru{sub 2}TiAl (−62.7 ± 3.5); Ru{sub 2}VAl (−30.9 ± 1.6); Ru{sub 2}ZrAl (−64.5 ± 1.5). Values were compared with those from published first principles calculations and the OQMD (Open Quantum Materials Database). Lattice parameters of these compounds were determined using X-ray diffraction analysis (XRD). Microstructures were identified using scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS)

Dual-Polarized Planar Phased Array Analysis for Meteorological Applications

Directory of Open Access Journals (Sweden)

Chen Pang

2015-01-01

Full Text Available This paper presents a theoretical analysis for the accuracy requirements of the planar polarimetric phased array radar (PPPAR in meteorological applications. Among many factors that contribute to the polarimetric biases, four factors are considered and analyzed in this study, namely, the polarization distortion due to the intrinsic limitation of a dual-polarized antenna element, the antenna pattern measurement error, the entire array patterns, and the imperfect horizontal and vertical channels. Two operation modes, the alternately transmitting and simultaneously receiving (ATSR mode and the simultaneously transmitting and simultaneously receiving (STSR mode, are discussed. For each mode, the polarimetric biases are formulated. As the STSR mode with orthogonal waveforms is similar to the ATSR mode, the analysis is mainly focused on the ATSR mode and the impacts of the bias sources on the measurement of polarimetric variables are investigated through Monte Carlo simulations. Some insights of the accuracy requirements are obtained and summarized.

Determination of dissociation enthalpies of KPbF3, RbPbF3, CsPbF3 complex molecules

International Nuclear Information System (INIS)

Boltalin, A.I.; Rykov, A.N.; Korenev, Yu.M.

1990-01-01

Isomolecular reactions in MPbF 3(g) -BeF 2(g) systems where M=K, Rb, Cs are studied using Knudsen effusion technique with mass-spectral analysis of evaporation products. Enthalpy values of dissociation of MPbF 3 molecules per lead difluoride and alkali metal fluoride which are equal to 212.1±12.6 kJ/mol for CsPbF 3 are determined

Joint Analysis of BICEP2/Keck Array and Planck Data

DEFF Research Database (Denmark)

Ade, P. A. R.; Aghanim, N.; Ahmed, Z.

2015-01-01

We report the results of a joint analysis of data from BICEP2/Keck Array and Planck. BICEP2 and Keck Array have observed the same approximately 400 deg2 patch of sky centered on RA 0 h, Dec. -57.5°. The combined maps reach a depth of 57 nK deg in Stokes Q and U in a band centered at 150 GHz. Planck...... GHz to a lensed-ΛCDM model that includes dust and a possible contribution from inflationary gravitational waves (as parametrized by the tensor-to-scalar ratio r), using a prior on the frequency spectral behavior of polarized dust emission from previous Planck analysis of other regions of the sky. We...... present an alternative analysis which is similar to a map-based cleaning of the dust contribution, and show that this gives similar constraints. The final result is expressed as a likelihood curve for r, and yields an upper limit r 0.05

The solvent effect on the enthalpy of hydrolysis of cyclic adenosine 3',5'-monophosphate : a quantum chemical study

NARCIS (Netherlands)

Scheffers - Sap, Miek; Buck, H.M.

1978-01-01

The solvent effect on the enthalpy of hydrolysis has been studied by the Extended-Hückel method for the hydrolysis reactions of cyclic adenosine 3',5'-monophosphate (cyclic 3',5'-AMP) and related cyclic phosphate diesters. The results show that the difference in enthalpy of hydrolysis between cyclic

A proposal to investigate higher enthalpy geothermal systems in the USA

Science.gov (United States)

Elders, W. A.

2013-12-01

After more than 50 years of development only ~3,400 MWe of electric power is currently being produced from geothermal resources in the USA. That is only about 0.33% of the country's total installed electrical capacity. In spite of the large demonstrated potential of geothermal resources, only ~2,500 MWe of new geothermal electrical capacity are under development, and the growth rate of this environmentally benign energy resource is overshadowed by the rapid increase in the installed capacity of wind and solar energy. Most of the new geothermal developments in the USA involve relatively small, moderate-temperature, geothermal systems. In contrast, development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Disadvantages include that the fact that locations of suitable geothermal systems are restricted to young volcanic terrains, production of very high enthalpy fluids usually requires drilling deeper wells and may require enhanced geothermal (EGS) technology, and drilling deep into hot hostile environments is technologically challenging. However the potential for very favorable economic returns suggests that the USA should begin developing such a program. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope an investigation. An excellent example of such a collaboration is the Iceland Deep Drilling Project (IDDP) which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. This industry-government consortium planned to drill a deep well in the volcanic caldera of Krafla in NE Iceland. However drilling had to be terminated at 2.1 km depth when 900°C rhyolite magma flowed into the well. The resultant well was highly

Blind Time-Frequency Analysis for Source Discrimination in Multisensor Array Processing

National Research Council Canada - National Science Library

Amin, Moeness

1999-01-01

.... We have clearly demonstrated, through analysis and simulations, the offerings of time-frequency distributions in solving key problems in sensor array processing, including direction finding, source...

Excess enthalpies of the ternary mixtures: {tetrahydrofuran + 3-methylpentane + (octane or decane)} at the temperature 298.15 K

International Nuclear Information System (INIS)

Wang Zhaohui; Benson, George C.; Lu, Benjamin C.-Y.

2003-01-01

Measurements of excess molar enthalpies at the temperature 298.15 K in a flow microcalorimeter, are reported for the two ternary mixtures {X 1 C 4 H 8 O + X 2 CH 3 CH 2 CH(CH 3 )CH 2 CH 3 + (1-X 1 -X 2 )CH 3 (CH 2 ) v-2 CH 3 } 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

Methanol wetting enthalpy on few-layer graphene decorated hierarchical carbon foam for cooling applications

Energy Technology Data Exchange (ETDEWEB)

Paul, R., E-mail: paul24@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Zemlyanov, D. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Voevodin, A.A.; Roy, A.K. [Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Fisher, T.S. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Department of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States)

2014-12-01

Vertical few-layer thick graphene petals are grown on macro-porous carbon foam surfaces having an intrinsic open porosity of 75%. This provides a hierarchical porous structure with a potential for surface adsorption/desorption or wetting/dewetting based thermal energy storage applications. Carbon foams have a combined advantage of large surface area and high thermal conductivity critical for thermal energy storage, but they are prone to oxidation and exhibit low adsorption enthalpies for lightweight hydrocarbons. Here we report graphene petal decoration of carbon foam surfaces and subsequent chemical modification through boron nitride incorporation in hexagonal carbon planes of both carbon foams and graphene petals. This chemically reactive hierarchical structure is characterized with FESEM, Raman, XRD, and XPS measurements. Methanol wetting enthalpy of this three-dimensional hierarchical material was measured with a solution calorimeter, and had shown a six fold increase (from 78 to 522 J/g of foam) as compared to the carbon foam prior to the surface modification. Influences of petal decoration on the surface morphology of carbon foam, BN chemical modification, structure and stoichiometry of the hierarchical material surface, and methanol wetting enthalpy improvement are discussed in detail. The applicability of this hierarchical porous material for thermal energy applications is established. - Highlights: • 500 nm thick few layer graphene petals decoration vertically on macroporous carbon foam surface. • Microwave heating assisted chemical treatment for boron-nitride modification. • Defective petals edges due to boron nitride domain formation. • 20 at. % boron and nitrogen incorporation. • Six fold increase in methanol wetting enthalpy on boron-nitride modification.

Methanol wetting enthalpy on few-layer graphene decorated hierarchical carbon foam for cooling applications

International Nuclear Information System (INIS)

Paul, R.; Zemlyanov, D.; Voevodin, A.A.; Roy, A.K.; Fisher, T.S.

2014-01-01

Vertical few-layer thick graphene petals are grown on macro-porous carbon foam surfaces having an intrinsic open porosity of 75%. This provides a hierarchical porous structure with a potential for surface adsorption/desorption or wetting/dewetting based thermal energy storage applications. Carbon foams have a combined advantage of large surface area and high thermal conductivity critical for thermal energy storage, but they are prone to oxidation and exhibit low adsorption enthalpies for lightweight hydrocarbons. Here we report graphene petal decoration of carbon foam surfaces and subsequent chemical modification through boron nitride incorporation in hexagonal carbon planes of both carbon foams and graphene petals. This chemically reactive hierarchical structure is characterized with FESEM, Raman, XRD, and XPS measurements. Methanol wetting enthalpy of this three-dimensional hierarchical material was measured with a solution calorimeter, and had shown a six fold increase (from 78 to 522 J/g of foam) as compared to the carbon foam prior to the surface modification. Influences of petal decoration on the surface morphology of carbon foam, BN chemical modification, structure and stoichiometry of the hierarchical material surface, and methanol wetting enthalpy improvement are discussed in detail. The applicability of this hierarchical porous material for thermal energy applications is established. - Highlights: • 500 nm thick few layer graphene petals decoration vertically on macroporous carbon foam surface. • Microwave heating assisted chemical treatment for boron-nitride modification. • Defective petals edges due to boron nitride domain formation. • 20 at. % boron and nitrogen incorporation. • Six fold increase in methanol wetting enthalpy on boron-nitride modification

The enthalpies of formation of neutral and charged components of saturated vapor over europium dichloride

International Nuclear Information System (INIS)

Pogrebnoj, A.M.; Kudin, L.S.

2003-01-01

Composition of saturated vapor over europium dichloride was studied by the method of high-temperature mass spectrometry in the temperature range of 1154 - 1267 K. For neutral components of the vapor, represented by monomer and dimer molecules, partial pressures were determined. Enthalpies of sublimation of europium dichloride Δ s H 0 (298 K) as monomers (338 ± 9) and dimers (407 ± 20 kJ/mol) were calculated. Equilibrium constants of ion-molecular and ion-ionic reactions were measured, their enthalpies being ascertained. Enthalpies of formation of molecules and ions Δ f H 0 (298 K) were calculated: -486 ± 11 (EuCl 2 ), -1242 ± 22 (Eu 2 Cl 4 ), 1 ± 12 (Eu 2 Cl 2 + ), -347 ± 20 (Eu 2 Cl 3 + ), -1111 ± 42 (Eu 3 Cl 5 + ), -975 ± 20 (EuCl 3 - ), -1309 ± 17(EuCl 4 - ), -1734 ± 20 (Eu 2 Cl 5 - ) kJ/mol [ru

Design and analysis of high gain array antenna for wireless communication applications

Directory of Open Access Journals (Sweden)

Sri Jaya LAKSHMI

2015-05-01

Full Text Available The array of antennas generally used for directing the radiated power towards a desired angular sector. Arrays can be used to synthesize a required pattern that cannot be achieved with a single element. The geometrical arrangement, number of elements, phases of the array elements and relative amplitudes depends on the angular pattern. This paper is focused on the issues related to the design and implementation of 4×1 array microstrip antenna with aperture coupled corporate feed for wireless local area network applications. Parametric analysis with change in element spacing is attempted in this work to understand the directional characteristics of the radiation pattern. Gain of more than 14 db and the efficiency more than 93% is achieved from the current design at desired frequency band.

Solid-State Characterization and Relative Formation Enthalpies To Evaluate Stability of Cocrystals of an Antidiabetic Drug.

Science.gov (United States)

Duggirala, Naga Kiran; Frericks Schmidt, Heather L; Lei, Zhaohui; Zaworotko, Michael J; Krzyzaniak, Joseph F; Arora, Kapildev K

2018-05-07

The current study integrates formation enthalpy and traditional slurry experiments to quickly assess the physical stability of cocrystal drug substance candidates for their potential to support drug development. Cocrystals of an antidiabetic drug (GKA) with nicotinamide (NMA), vanillic acid (VLA), and ethyl vanillin (EVL) were prepared and characterized by powder X-ray diffractometry (PXRD), spectroscopic, and thermal techniques. The formation enthalpies of the cocrystals, and their physical mixtures (GKA + coformer) were measured by the differential scanning calorimetry (DSC) method reported by Zhang et al. [ Cryst. Growth Des. 2012 , 12 ( 8 ), 4090 - 4097 ]. The experimentally measured differences in the relative formation enthalpies obtained by integrating the heat flow of each cocrystal against the respective physical mixture were correlated to the physical stability of the cocrystals in the solid state. The relative formation enthalpies of all of the cocrystals studied suggest that the cocrystals are not physically stable at room temperature versus their physical mixtures. To further address relative stability, the cocrystals were slurried in 30% v/v aqueous ethanol, and it was observed that all of the cocrystals revert to GKA within 48 h at room temperature. The slurry experiments are consistent with the relative instability of the cocrystals with respect to their physical mixtures suggested by the DSC results.

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

Science.gov (United States)

Fogolari, Federico; Corazza, Alessandra; Esposito, Gennaro

2018-01-01

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.

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.

Investigating ultra high-enthalpy geothermal systems: a collaborative initiative to promote scientific opportunities

Science.gov (United States)

Elders, W. A.; Nielson, D.; Schiffman, P.; Schriener, A., Jr.

2014-12-01

Scientists, engineers, and policy makers gathered at a workshop in the San Bernardino Mountains of southern California in October 2013 to discuss the science and technology involved in developing high-enthalpy geothermal fields. A typical high-enthalpy geothermal well between 2000 and 3000 m deep produces a mixture of hot water and steam at 200-300 °C that can be used to generate about 5-10 MWe of electric power. The theme of the workshop was to explore the feasibility and economic potential of increasing the power output of geothermal wells by an order of magnitude by drilling deeper to reach much higher pressures and temperatures. Development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Plans for resource assessment and drilling in such higher enthalpy areas are already underway in Iceland, New Zealand, and Japan. There is considerable potential for similar developments in other countries that already have a large production of electricity from geothermal steam, such as Mexico, the Philippines, Indonesia, Italy, and the USA. However drilling deeper involves technical and economic challenges. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope of investigation. An excellent example of such collaboration is the Iceland Deep Drilling Project (IDDP), which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs, and this approach could serve as model for future developments elsewhere. A planning committee was formed to explore creating a similar initiative in the USA.

The enthalpies of formation of alkyl carbamates: Experimental and computational redetermination

International Nuclear Information System (INIS)

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

2013-01-01

Highlights: ► Combustion calorimetry was used to redetermine Δ f H m o (cr) of methyl and ethyl carbamates. ► Δ cr g H m o of methyl and ethyl carbamates were redetermined by Calvet Microcalorimetry. ► Gas-phase Δ f H m o of the studied compounds have been derived from the experimental values of Δ f H m o (cr) and Δ cr g H m o . ► Gas-phase Δ f H m o of the studied compounds have been calculated by computational thermochemistry. ► The obtained Δ f H m o (g) for the alkylcarbamates are discussed versus literature values for the same compounds. - Abstract: In the present work, a redetermination of thermochemical data of methyl carbamate and ethyl carbamate was performed by both experimental and computational techniques. Their gas-phase standard (p o = 0.1 MPa) molar enthalpies of formation, Δ f H m o (g), at T = 298.15 K, were derived from the standard molar enthalpies of formation, in the crystalline phase, Δ f H m o (cr), and from the standard molar enthalpies of sublimation, Δ cr g H m o at T = 298.15 K, measured, respectively, by static bomb combustion calorimetry and high temperature Calvet microcalorimetry. The experimental results were compared with computational data, calculated at the G3(MP2)//B3LYP level, as well as with values reported in the literature. At the B3LYP/6-31G(d) level of theory, the molecular structure of both carbamates was obtained.

The enthalpy of solid scandium in the temperature range 406 - 1812 K

International Nuclear Information System (INIS)

Lyapunov, K.M.; Baginskij, A.V.; Stankus, S.V.

2001-01-01

Enthalpy of pure scandium was measured on massive calorimeter in the range from 406 to 1812 K by mixing method. The enthalpy of face centered close cubic lattice - body centered cubic lattice transformation is equal to ΔH t 4068 J/mol. Obtained value within the limits of error is compatible with the results given earlier (4009 J/mol). The dependence of the middle specific heat of scandium C p (T) on the temperature was shown in correlation with the results of other works. The results of the conducted experiments reinforce the conclusion made earlier about an absence (or a little) in the decomposition of an anharmonic component of the oscillation specific heat of scandium C p a (T) members proportional to the first or the second degrees of temperature [ru

Evaluation of enthalpy of interfacial reactions from temperature dependency of interfacial equilibrium

International Nuclear Information System (INIS)

Kallay, Nikola; Cop, Ana

2005-01-01

Temperature dependency of equilibrium at metal oxide-aqueous electrolyte solution interface was analyzed by numerical simulation. Derivations of inner surface potential with respect to temperature were performed at constant values of several different parameters. When surface charge density in inner plane was kept constant the reasonable results were obtained, i.e. the electrostatic contribution to enthalpy of protonation of amphotheric surface sites was found to be positive in the pH region below the point of zero potential and negative above this point. All other examined possibilities produced opposite results. Derivation of empirical interfacial equilibrium constant at constant surface potential indicated that electrostatic effect on protonation entropy is negligible and that electrostatic contributions to reaction Gibbs energy and enthalpy are equal and directly related to the surface potential in the inner plane

Isotope effect in enthalpy of solvation of the lithium ion

International Nuclear Information System (INIS)

Krestov, G.A.; Egorov, G.I.; Korolev, V.P.

1989-01-01

At 298.15 K, the authors determined the standard enthalpies of solution for 6 LiCl and 7 LiCl in water, heavy water, dimethylsulfoxide (DMSO) and aqueous solutions of DMSO. The authors have established that solvation of 6 Li + is differentiated in water and DMSO to a greater degree than for 7 Li +

Experimental Determination of the Formation Enthalpy of Calcium Cobaltate from Sol–Gel Precursors

DEFF Research Database (Denmark)

Holgate, Tim C.; Wu, NingYu; Van Nong, Ngo

2017-01-01

Calcium cobaltate (Ca3Co4O9) remains one of the most promising p-type oxide materials for high-temperature thermoelectric energy conversion. While much progress has been made in refining our understanding of the unique structure of the material, as well as optimization of the transport properties...... as observations of its decomposition into the Ca3Co2O6 phase. The reaction enthalpy of forming Ca3Co4O9 from CaCO3 and Co3O4 sol–gel precursors was determined to be +284 (±2%) kJ/mol, leading to a standard enthalpy of Ca3Co4O9 of −3307 (±3.5%) kJ/mol....

Oxidation potentials, Gibbs energies, enthalpies and entropies of actinide ions in aqueous solutions

International Nuclear Information System (INIS)

1977-01-01

The values of the Gibbs energy, enthalpy, and entropy of different actinide ions, thermodynamic characteristics of the processes of hydration of these ions, and the presently known ionization potentials of actinides are given. The enthalpy and entropy components of the oxidation potentials of actinide elements are considered. The curves of the dependence of the Gibbs energy of ion formation on the atomic number of the element and the Frost diagrams are analyzed. The diagram proposed by Frost represents the graphical dependence of the Gibbs energy of hydrated ions on the degree of oxidation of the element. Using the Frost diagram it is easy to establish whether a given ion is stable to disproportioning

Cluster Computing For Real Time Seismic Array Analysis.

Science.gov (United States)

Martini, M.; Giudicepietro, F.

A seismic array is an instrument composed by a dense distribution of seismic sen- sors that allow to measure the directional properties of the wavefield (slowness or wavenumber vector) radiated by a seismic source. Over the last years arrays have been widely used in different fields of seismological researches. In particular they are applied in the investigation of seismic sources on volcanoes where they can be suc- cessfully used for studying the volcanic microtremor and long period events which are critical for getting information on the volcanic systems evolution. For this reason arrays could be usefully employed for the volcanoes monitoring, however the huge amount of data produced by this type of instruments and the processing techniques which are quite time consuming limited their potentiality for this application. In order to favor a direct application of arrays techniques to continuous volcano monitoring we designed and built a small PC cluster able to near real time computing the kinematics properties of the wavefield (slowness or wavenumber vector) produced by local seis- mic source. The cluster is composed of 8 Intel Pentium-III bi-processors PC working at 550 MHz, and has 4 Gigabytes of RAM memory. It runs under Linux operating system. The developed analysis software package is based on the Multiple SIgnal Classification (MUSIC) algorithm and is written in Fortran. The message-passing part is based upon the LAM programming environment package, an open-source imple- mentation of the Message Passing Interface (MPI). The developed software system includes modules devote to receiving date by internet and graphical applications for the continuous displaying of the processing results. The system has been tested with a data set collected during a seismic experiment conducted on Etna in 1999 when two dense seismic arrays have been deployed on the northeast and the southeast flanks of this volcano. A real time continuous acquisition system has been simulated by

Design and Analysis Tools for Deployable Solar Array Systems, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Large, lightweight, deployable solar array structures have been identified as a key enabling technology for NASA with analysis and design of these structures being...

Design and Analysis Tools for Deployable Solar Array Systems, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Large, lightweight, deployable solar array structures have been identified as a key enabling technology for NASA with analysis and design of these structures being...

A user-friendly workflow for analysis of Illumina gene expression bead array data available at the arrayanalysis.org portal.

Science.gov (United States)

Eijssen, Lars M T; Goelela, Varshna S; Kelder, Thomas; Adriaens, Michiel E; Evelo, Chris T; Radonjic, Marijana

2015-06-30

Illumina whole-genome expression bead arrays are a widely used platform for transcriptomics. Most of the tools available for the analysis of the resulting data are not easily applicable by less experienced users. ArrayAnalysis.org provides researchers with an easy-to-use and comprehensive interface to the functionality of R and Bioconductor packages for microarray data analysis. As a modular open source project, it allows developers to contribute modules that provide support for additional types of data or extend workflows. To enable data analysis of Illumina bead arrays for a broad user community, we have developed a module for ArrayAnalysis.org that provides a free and user-friendly web interface for quality control and pre-processing for these arrays. This module can be used together with existing modules for statistical and pathway analysis to provide a full workflow for Illumina gene expression data analysis. The module accepts data exported from Illumina's GenomeStudio, and provides the user with quality control plots and normalized data. The outputs are directly linked to the existing statistics module of ArrayAnalysis.org, but can also be downloaded for further downstream analysis in third-party tools. The Illumina bead arrays analysis module is available at http://www.arrayanalysis.org . A user guide, a tutorial demonstrating the analysis of an example dataset, and R scripts are available. The module can be used as a starting point for statistical evaluation and pathway analysis provided on the website or to generate processed input data for a broad range of applications in life sciences research.

Diluent and extractant effects on the enthalpy of extraction of uranium(VI) and americium(III) nitrates by trialkyl phosphates

International Nuclear Information System (INIS)

Srinivasan, T.G.; Vasudeva Rao, P.R.; Sood, D.D.

1998-01-01

The effect of various diluents such as n-hexane, n-heptane n-octane, isooctane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-hexadecane, cyclohexane, benzene, toluene, p-xylene, mesitylene and o-dichlorobenzene on the enthalpy of extraction of uranyl nitrate by tri-n-amyl phosphate (TAP) over the temperature range 283 K--333 K has been studied. The results indicate that the enthalpy of extraction does not vary significantly with the diluents studied. Also enthalpies of extraction of uranyl nitrate and americium(III) nitrate by neutral organo phosphorous extractants such as tri-n-butyl phosphate (TBP), tri-n-amyl phosphate (TAP), tri-sec-butyl phosphate (TsBP), tri-isoamyl phosphate (TiAP) and tri-n-hexyl phosphate (THP) have been studied. An attempt has been made to explain the trends, on the basis of the nature of the solvate formed and the different terms which contribute to the overall enthalpy change

Analysis of Chinese women with primary ovarian insufficiency by high resolution array-comparative genomic hybridization.

Science.gov (United States)

Liao, Can; Fu, Fang; Yang, Xin; Sun, Yi-Min; Li, Dong-Zhi

2011-06-01

Primary ovarian insufficiency (POI) is defined as a primary ovarian defect characterized by absent menarche (primary amenorrhea) or premature depletion of ovarian follicles before the age of 40 years. The etiology of primary ovarian insufficiency in human female patients is still unclear. The purpose of this study is to investigate the potential genetic causes in primary amenorrhea patients by high resolution array based comparative genomic hybridization (array-CGH) analysis. Following the standard karyotyping analysis, genomic DNA from whole blood of 15 primary amenorrhea patients and 15 normal control women was hybridized with Affymetrix cytogenetic 2.7M arrays following the standard protocol. Copy number variations identified by array-CGH were confirmed by real time polymerase chain reaction. All the 30 samples were negative by conventional karyotyping analysis. Microdeletions on chromosome 17q21.31-q21.32 with approximately 1.3 Mb were identified in four patients by high resolution array-CGH analysis. This included the female reproductive secretory pathway related factor N-ethylmaleimide-sensitive factor (NSF) gene. The results of the present study suggest that there may be critical regions regulating primary ovarian insufficiency in women with a 17q21.31-q21.32 microdeletion. This effect might be due to the loss of function of the NSF gene/genes within the deleted region or to effects on contiguous genes.

Mass accretion and nested array dynamics from Ni-Clad Ti-Al wire array Z pinches

International Nuclear Information System (INIS)

Jones, Brent Manley; Jennings, Christopher A.; Coverdale, Christine Anne; Cuneo, Michael Edward; Maron, Yitzhak; LePell, Paul David; Deeney, Christopher

2010-01-01

Analysis of 50 mm diameter wire arrays at the Z Accelerator has shown experimentally the accretion of mass in a stagnating z pinch and provided insight into details of the radiating plasma species and plasma conditions. This analysis focused on nested wire arrays with a 2:1 (outeninner) mass, radius, and wire number ratio where Al wires were fielded on the outer array and Ni-clad Ti wires were fielded on the inner array.In this presentation, we will present analysis of data from other mixed Al/Ni-clad Ti configurations to further evaluate nested wire array dynamics and mass accretion. These additional configurations include the opposite configuration to that described above (Ni-clad Ti wires on the outer array, with Al wires on the inner array) as well as higher wire number Al configurations fielded to vary the interaction of the two arrays. These same variations were also assessed for a smaller diameter nested array configuration (40 mm). Variations in the emitted radiation and plasma conditions will be presented, along with a discussion of what the results indicate about the nested array dynamics. Additional evidence for mass accretion will also be presented.

Enthalpies of potassium iodide dissolution in dimethyl acetamide mixtures with water

International Nuclear Information System (INIS)

Privalova, N.M.; Gritsenko, S.I.; Vorob'ev, A.F.

1986-01-01

Enthalpies of potassium iodide dissolution in mixed dimethyl acetamide - water solvent at 298.15 K in the whole range of dimethyl acetamide compositions are measured by the calorimetric method. From the plots of KI dissolution enthalpy dependence and dependence of experimental ΔH p∞ 0 value deviations from calculational ones on solvent composition, as well as from the results of calculation of solvate shell composition of potassium iodide ions in the mixed solvent, it is obvious that in the region of 0-15 mol% concentrations of dimethyl acetamide insufficient enrichment of solvate ion shells by dimethyl acetamide (DMAA) occurs, in the region of 15-40 mol% DMAA compositions enrichment of solvate shells of ions by water occurs, in the region of 40-100 mol% DMAA enrichment of solvate ion shells by the organic component in comparison with mixture compostion occurs. Maximum enrichment of solvate ion shells by mixture components in three above mentioned regions of the mixed solvent occurs at 10, 30 and 80 mol% DMAA concentrations

Gravitational wave detection and data analysis for pulsar timing arrays

NARCIS (Netherlands)

Haasteren, Rutger van

2011-01-01

Long-term precise timing of Galactic millisecond pulsars holds great promise for measuring long-period (months-to-years) astrophysical gravitational waves. In this work we develop a Bayesian data analysis method for projects called pulsar timing arrays; projects aimed to detect these gravitational

Analysis of radiation damage in on-orbit solar array of Venus explorer Akatsuki

International Nuclear Information System (INIS)

Toyota, Hiroyuki; Shimada, Takanobu; Takahashi, You; Imamura, Takeshi; Hada, Yuko; Ishii, Takako T.; Isobe, Hiroaki; Asai, Ayumi; Shiota, Daikou

2013-01-01

This paper describes an analysis of radiation damage in solar array of Venus explorer Akatsuki observed on orbit. The output voltage of the solar array have shown sudden drops, which are most reasonably associated with radiation damage, three times since its launch. The analysis of these radiation damages is difficult, because no direct observation data of the spectra and the amount of the high-energy particles is available. We calculated the radiation damage using the relative damage coefficient (RDC) method assuming a typical spectral shape of protons. (author)

SGC method for predicting the standard enthalpy of formation of pure compounds from their molecular structures

International Nuclear Information System (INIS)

Albahri, Tareq A.; Aljasmi, Abdulla F.

2013-01-01

Highlights: • ΔH° f is predicted from the molecular structure of the compounds alone. • ANN-SGC model predicts ΔH° f with a correlation coefficient of 0.99. • ANN-MNLR model predicts ΔH° f with a correlation coefficient of 0.90. • Better definition of the atom-type molecular groups is presented. • The method is better than others in terms of combined simplicity, accuracy and generality. - Abstract: A theoretical method for predicting the standard enthalpy of formation of pure compounds from various chemical families is presented. Back propagation artificial neural networks were used to investigate several structural group contribution (SGC) methods available in literature. The networks were used to probe the structural groups that have significant contribution to the overall enthalpy of formation property of pure compounds and arrive at the set of groups that can best represent the enthalpy of formation for about 584 substances. The 51 atom-type structural groups listed provide better definitions of group contributions than others in the literature. The proposed method can predict the standard enthalpy of formation of pure compounds with an AAD of 11.38 kJ/mol and a correlation coefficient of 0.9934 from only their molecular structure. The results are further compared with those of the traditional SGC method based on MNLR as well as other methods in the literature

Numeric-modeling sensitivity analysis of the performance of wind turbine arrays

Energy Technology Data Exchange (ETDEWEB)

Lissaman, P.B.S.; Gyatt, G.W.; Zalay, A.D.

1982-06-01

An evaluation of the numerical model created by Lissaman for predicting the performance of wind turbine arrays has been made. Model predictions of the wake parameters have been compared with both full-scale and wind tunnel measurements. Only limited, full-scale data were available, while wind tunnel studies showed difficulties in representing real meteorological conditions. Nevertheless, several modifications and additions have been made to the model using both theoretical and empirical techniques and the new model shows good correlation with experiment. The larger wake growth rate and shorter near wake length predicted by the new model lead to reduced interference effects on downstream turbines and hence greater array efficiencies. The array model has also been re-examined and now incorporates the ability to show the effects of real meteorological conditions such as variations in wind speed and unsteady winds. The resulting computer code has been run to show the sensitivity of array performance to meteorological, machine, and array parameters. Ambient turbulence and windwise spacing are shown to dominate, while hub height ratio is seen to be relatively unimportant. Finally, a detailed analysis of the Goodnoe Hills wind farm in Washington has been made to show how power output can be expected to vary with ambient turbulence, wind speed, and wind direction.

Accurate Gas Phase Formation Enthalpies of Alloys and Refractories Decomposition Products

KAUST Repository

Minenkov, Yury; Sliznev, Valery V.; Cavallo, Luigi

2017-01-01

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

Electrical resistivities and solvation enthalpies for solutions of salts in liquid alkali metals

International Nuclear Information System (INIS)

Hubberstey, P.; Dadd, A.T.

1982-01-01

An empirical correlation is shown to exist between the resistivity coefficients drho/dc for solutes in liquid alkali metals and the corresponding solvation enthalpies Usub(solvn) of the neutral gaseous solute species. Qualitative arguments based on an electrostatic solvation model in which the negative solute atom is surrounded by a solvation sphere of positive solvent ion cores are used to show that both parameters are dependent on the charge density of the solute atom and hence on the extent of charge transfer from solvent to solute. Thus as the charge density of the solute increases, the solvation enthalpy increases regularly and the resistivity coefficients pass through a maximum to give the observed approximately parabolic drho/dc versus Usub(solvn) relationship. (Auth.)

Boundary Layer Transition and Trip Effectiveness on an Apollo Capsule in the JAXA High Enthalpy Shock Tunnel (HIEST) Facility

Science.gov (United States)

Kirk, Lindsay C.; Lillard, Randolph P.; Olejniczak, Joseph; Tanno, Hideyuki

2015-01-01

Computational assessments were performed to size boundary layer trips for a scaled Apollo capsule model in the High Enthalpy Shock Tunnel (HIEST) facility at the JAXA Kakuda Space Center in Japan. For stagnation conditions between 2 MJ/kg and 20 MJ/kg and between 10 MPa and 60 MPa, the appropriate trips were determined to be between 0.2 mm and 1.3 mm high, which provided kappa/delta values on the heatshield from 0.15 to 2.25. The tripped configuration consisted of an insert with a series of diamond shaped trips along the heatshield downstream of the stagnation point. Surface heat flux measurements were obtained on a capsule with a 250 mm diameter, 6.4% scale model, and pressure measurements were taken at axial stations along the nozzle walls. At low enthalpy conditions, the computational predictions agree favorably to the test data along the heatshield centerline. However, agreement becomes less favorable as the enthalpy increases conditions. The measured surface heat flux on the heatshield from the HIEST facility was under-predicted by the computations in these cases. Both smooth and tripped configurations were tested for comparison, and a post-test computational analysis showed that kappa/delta values based on the as-measured stagnation conditions ranged between 0.5 and 1.2. Tripped configurations for both 0.6 mm and 0.8 mm trip heights were able to effectively trip the flow to fully turbulent for a range of freestream conditions.

Enthalpy-Entropy Compensation in the Binding of Modulators at Ionotropic Glutamate Receptor GluA2

DEFF Research Database (Denmark)

Krintel, Christian; Francotte, Pierre; Pickering, Darryl S

2016-01-01

of 5 was examined with x-ray crystallography, showing that the only change compared to that of earlier compounds was the orientation of Ser-497 pointing toward the hydroxyl group of 5. The favorable enthalpy can be explained by the formation of a hydrogen bond from the side-chain hydroxyl group of Ser...... of modulators BPAM97 (2) and BPAM344 (3) into a hydroxyl group (BPAM557 (4) and BPAM521 (5), respectively), leads to a more favorable binding enthalpy (ΔH, kcal/mol) from −4.9 (2) and −7.5 (3) to −6.2 (4) and −14.5 (5), but also a less favorable binding entropy (−TΔS, kcal/mol) from −2.3 (2) and −1.3 (3) to −0......-497 to the hydroxyl group of 5, whereas the unfavorable entropy might be due to desolvation effects combined with a conformational restriction of Ser-497 and 5. In summary, this study shows a remarkable example of enthalpy-entropy compensation in drug development accompanied with a likely explanation...

Rapid prenatal diagnosis of cytogenetic abnormalities by array CGH analysis

Science.gov (United States)

Array CGH analysis has been shown to be highly accurate for rapid detection of chromosomal aneuploidies and submicroscopic deletions or duplications on fetal DNA samples in a clinical prenatal diagnostic setting. The objective of this study is to present our "post-validation phase" experience with ...

The intermetallic ThRh5: microstructure and enthalpy increments

International Nuclear Information System (INIS)

Banerjee, Aparna; Joshi, A.R.; Kaity, Santu; Mishra, R.; Roy, S.B.

2013-01-01

Actinide intermetallics are one of the most interesting and important series of compounds. Thermochemistry of these compounds play significant role in understand the nature of bonding in alloys and nuclear fuel performance. In the present paper we report synthesis and characterization of thorium based intermetallic compound ThRh 5 (s) by SEM/EDX technique. The mechanical properties and enthalpy increment as a function of temperature of the alloy has been measured. (author)

Problem-based learning in teaching chemistry: enthalpy changes in systems

Science.gov (United States)

Ayyildiz, Yildizay; Tarhan, Leman

2018-01-01

Problem-based learning (PBL) as a teaching strategy has recently become quite widespread in especially chemistry classes. Research has found that students, from elementary through college, have many alternative conceptions regarding enthalpy changes in systems. Although there are several studies focused on identifying student alternative conceptions and misunderstandings of this subject, studies on preventing the formation of these alternative conceptions are limited.

Combustion energies and standard molar enthalpies of formation for the complexes of the first-row transitional metal chlorides with L-α-histidine

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

Seven novel solid complexes of the first-row transitional metal with L-α-histidine were synthesized, and their compositions were determined. The constant-volume combustion energies of the complexes were measured by a precision rotation bomb calorimeter. The standard molar enthalpies of combustion and the standard molar enthalpies of formation were calculated. The results indicated thatthe plots of the standard enthalpies of formation against the atomic number of the metal show a regularity of zigzag.

Investigation of variation of additional enthalpy of proteins with respect to pH by statistical mechanical methods

International Nuclear Information System (INIS)

Oylumoglu, G.

2005-01-01

In this study variation of additional enthalpy with respect to pH has been investigated by the statistical mechanical methods.. To bring up the additional effect, the partition function of the proteins are calculated by single protein molecule approximation. From the partition function, free energies of the proteins are obtained and by this way additional free energy has been used in the calculation of the terms in the thermodynamical quantity. Additional enthalpy H D has been obtained by taking effective electric field E and constant dipole moment M as thermodynamical variables and using Maxwell Equations. In the presented semi phenomenological theory, necessary data are taken from the experimental study of P.L. Privalov. The variation in the additional enthalpy H D has been investigated in the pH interval of 1-5 and the results of the calculations are discussed for Lysozyme

Calorimetric determination of the enthalpy of 1-butyl-3-methylimidazolium bromide synthesis: a key quantity in thermodynamics of ionic liquids.

Science.gov (United States)

Paulechka, Yauheni U; Kabo, Andrey G; Blokhin, Andrey V

2009-11-05

The enthalpy of the 1-butyl-3-methylimidazolium bromide [C(4)mim]Br ionic liquid synthesis reaction 1-methylimidazole (liq) + 1-bromobutane (liq) --> [C(4)mim]Br (liq) was determined in a homemade small-volume isoperibol calorimeter to be Delta(r)H degrees (298) = -87.7 +/- 1.6 kJ x mol(-1). The activation energy for this reaction in a homogeneous system E(A) = 73 +/- 4 kJ x mol(-1) was found from the results of calorimetric measurements. The formation enthalpies for the crystalline and liquid [C(4)mim]Br were determined from the calorimetric data: Delta(f)H degrees (298)(cr) = -178 +/- 5 kJ x mol(-1) and Delta(f)H degrees (298)(liq) = -158 +/- 5 kJ x mol(-1). The ideal-gas formation enthalpy of this compound Delta(f)H degrees (298)(g) = 16 +/- 7 kJ x mol(-1) was calculated using the methods of quantum chemistry and statistical thermodynamics. The vaporization enthalpy of [C(4)mim]Br, Delta(vap)H degrees (298) = 174 +/- 9 kJ x mol(-1), was estimated from the experimental and calculated formation enthalpies. It was demonstrated that vapor pressure of this ionic liquid cannot be experimentally determined.

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....

Excess molar enthalpies of binary systems containing 2-octanone, hexanoic acid, or octanoic acid at T = 298.15 K

International Nuclear Information System (INIS)

Liao, Wei-Chen; Lin, Ho-mu; Lee, Ming-Jer

2012-01-01

Highlights: → An isothermal titration calorimeter was used for enthalpy data measurement. → The investigated binary systems contain 2-octanone, hexanoic acid, or octanoic acid. → The excess enthalpies are all positive except for mixtures containing DMSO and DMF. → The Peng-Robinson equation with two parameters yielded the best representation. - Abstract: An isothermal titration calorimeter was used to measure the excess molar enthalpies (H E ) of six binary systems at T = 298.15 K under atmospheric pressure. The systems investigated include (1-hexanol + 2-octanone), (1-octanol + 2-octanone), (1-hexanol + octanoic acid), (1-hexanol + hexanoic acid), {N,N-dimethylformamide (DMF) + hexanoic acid}, and {dimethyl sulfoxide (DMSO) + hexanoic acid}. The values of excess molar enthalpies are all positive except for the DMSO- and the DMF-containing systems. In the 1-hexanol with hexanoic acid or octanoic acid systems, the maximum values of H E are located around the mole fraction of 0.4 of 1-hexanol, but the H E vary nearly symmetrically with composition for other four systems. In addition to the modified Redlich-Kister and the NRTL models, the Peng-Robinson (PR) and the Patel-Teja (PT) equations of state were used to correlate the excess molar enthalpy data. The modified Redlich-Kister equation correlates the H E data to within about experimental uncertainty. The calculated results from the PR and the PT are comparable. It is indicated that the overall average absolute relative deviations (AARD) of the excess enthalpy calculations are reduced from 18.8% and 18.8% to 6.6% and 7.0%, respectively, as the second adjustable binary interaction parameter, k bij , is added in the PR and the PT equations. Also, the NRTL model correlates the H E data to an overall AARD of 10.8% by using two adjustable model parameters.

Numerical simulation of nonequilibrium flow in high-enthalpy shock tunnel

Energy Technology Data Exchange (ETDEWEB)

Kaneko, M.; Men' shov, I.; Nakamura, Y

2005-03-01

The flow field of a nozzle starting process with thermal and chemical nonequilibrium has been simulated. This flow is produced in high enthalpy impulse facilities such as the free piston shock tunnel. The governing equations are the axisymmetric, compressible Navier-Stokes equations. In this study, Park's two-temperature model, where air consists of five species, is used for defining the thermodynamic properties of air as a driven gas. The numerical scheme employed here is the hybrid scheme of the explicit and implicit methods, which was developed in our laboratory, along with AUSM{sup +} to evaluate inviscid fluxes. In the present simulation, the Mach number of an incident shock wave is set at M{sub s}=10.0. It corresponds to a specific enthalpy, h{sub 0}, of 12 MJ/kg. The results clearly show the complicated thermal and chemical nonequilibrium flow field around the end of the shock tube section and at the nozzle inlet during the initial stage of the nozzle starting process. They also suggest that the phenomenon of nozzle melting might be associated with a flow separation at the nozzle inlet.

Characterization and thermogravimetric analysis of lanthanide hexafluoroacetylacetone chelates.

Science.gov (United States)

Shahbazi, Shayan; Stratz, S Adam; Auxier, John D; Hanson, Daniel E; Marsh, Matthew L; Hall, Howard L

2017-01-01

This work reports the thermodynamic characterizations of organometallic species as a vehicle for the rapid separation of volatile nuclear fission products via gas chromatography due to differences in adsorption enthalpy. Because adsorption and sublimation thermodynamics are linearly correlated, there is considerable motivation to determine sublimation enthalpies. A method of isothermal thermogravimetric analysis, TGA-MS and melting point analysis are employed on thirteen lanthanide 1,1,1,5,5,5-hexafluoroacetylacetone complexes to determine sublimation enthalpies. An empirical correlation is used to estimate adsorption enthalpies of lanthanide complexes on a quartz column from the sublimation data. Additionally, four chelates are characterized by SC-XRD, elemental analysis, FTIR and NMR.

Melting point gram-atomic volumes and enthalpies of atomization for liquid elements

International Nuclear Information System (INIS)

Lamoreaux, R.H.

1976-01-01

Values of the gram-atomic volumes and enthalpies of atomization to the monatomic ideal gas state for liquid elements at their melting points are collected to facilitate predictions of the behavior of mixed systems. Estimated values are given for experimentally undetermined quantities

OpenMSI Arrayed Analysis Toolkit: Analyzing Spatially Defined Samples Using Mass Spectrometry Imaging

DEFF Research Database (Denmark)

de Raad, Markus; de Rond, Tristan; Rübel, Oliver

2017-01-01

://openmsinersc.gov), a platform for storing, sharing, and analyzing MSI data. By using a web-based python notebook (Jupyter), OMAAT is accessible to anyone without programming experience yet allows experienced users to leverage all features. OMAAT was :evaluated by analyzing an MSI data set of a high-throughput glycoside...... processing tools for the analysis of large arrayed MSI sample sets. The OpenMSI Arrayed Analysis Toolkit (OMAAT) is a software package that addresses the challenges of analyzing spatially defined samples in MSI data sets. OMAAT is written in Python and is integrated with OpenMSI (http...

Corollary from the Exact Expression for Enthalpy of Vaporization

OpenAIRE

A. A. Sobko

2011-01-01

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 paramet...

MTF measurement and analysis of linear array HgCdTe infrared detectors

Science.gov (United States)

Zhang, Tong; Lin, Chun; Chen, Honglei; Sun, Changhong; Lin, Jiamu; Wang, Xi

2018-01-01

The slanted-edge technique is the main method for measurement detectors MTF, however this method is commonly used on planar array detectors. In this paper the authors present a modified slanted-edge method to measure the MTF of linear array HgCdTe detectors. Crosstalk is one of the major factors that degrade the MTF value of such an infrared detector. This paper presents an ion implantation guard-ring structure which was designed to effectively absorb photo-carriers that may laterally defuse between adjacent pixels thereby suppressing crosstalk. Measurement and analysis of the MTF of the linear array detectors with and without a guard-ring were carried out. The experimental results indicated that the ion implantation guard-ring structure effectively suppresses crosstalk and increases MTF value.

The vaporization enthalpy and vapor pressure of S (+)-methamphetamine at T = 298.15 K by correlation gas chromatography

International Nuclear Information System (INIS)

Thornton, Melissa; Gobble, Chase; Chickos, James

2014-01-01

Highlights: • The vaporization enthalpy of (d)-methamphetamine was measured. • The vapor pressure of (d)-methamphetamine as a function of temperature was evaluated. • The vapor pressure of 4-benzylpiperidine as a function of temperature was evaluated. - Abstract: The vaporization enthalpy and vapor pressure of S (+)-methamphetamine is evaluated by correlation-gas chromatography. A vaporization enthalpy of (58.7 ± 4.3) kJ · mol −1 and a vapor pressure, p = (38 ± 9) Pa has been obtained using a variety of secondary aliphatic amines as standards. In addition, equations describing the vapor pressure temperature dependence are provided for standards and S (+)-methamphetamine covering the temperature range from T = 298.15 K to the boiling temperature. Boiling temperatures are reproduced within an interval of 8 K or less

Vapor pressure and enthalpy of vaporization of oil of catnip by correlation gas chromatography

International Nuclear Information System (INIS)

Simmons, Daniel; Gobble, Chase; Chickos, James

2016-01-01

Highlights: • Vaporization enthalpies of the nepetalactones from oil of catnip have been evaluated. • Vapor pressures from T = (298.15 to 350) K have been evaluated. • Oil of catnip has a vapor pressure similar to DEET at T = 298.15 K. - Abstract: The vaporization enthalpy and vapor pressure of the two nepetalactones found in Nepeta cataria have been evaluated by correlation gas chromatography. Vaporization enthalpies at T = 298.15 K of {(68.0 ± 1.9) and (69.4 ± 1.9)} kJ ⋅ mol"−"1 have been derived for the minor diastereomer, (4aS,7S,7aS)-nepetalactone, and major one, (4aS,7S,7aR)-nepetalactone, respectively. Vapor pressures also at T = 298.15 K of p = (1.2 ± 0.04) Pa and (0.91 ± 0.03) Pa have been evaluated for the minor and the major stereoisomer. In addition to being of interest because of the remarkable effect it has on various felids, oil of catnip is also quite effective in repelling mosquitoes, comparable to diethyl-m-toluamide (DEET). The vapor pressures evaluated in this work suggest that the two stereoisomers have similar volatility to DEET at ambient temperatures.

Solution enthalpy of potassium iodide in furfural and its mixtures with dimethylsulfoxide

International Nuclear Information System (INIS)

Vlasenko, K.K.; Belov, A.A.; Vorob'ev, A.F.

1986-01-01

Solution enthalpy of potassium iodide in furfural-dimethylsulfoxide mixtures at 298.15 K and furfural concentration 17.3-100% are determined experimentally. K + and I - ion solvate shell composition, which in the general case doesn't correspond to the mixed solvent composition, is calculated

Isosteric Vapor Pressure – Temperature Data for Water Sorption in Hardened Cement Paste: Enthalpy, Entropy and Sorption Isotherms at Different Temperatures

DEFF Research Database (Denmark)

Radjy, Fariborz; Sellevold, Erik J.; Hansen, Kurt Kielsgaard

. The accuracies for pressure, enthalpy and entropy are found to be 0.5% or less. PART II: The TPA-system has been used to generate water vapor pressure – temperature data for room temperature – and steam cured hardened cement pastes as well as porous vycor glass. The moisture contents range from saturated to dry...... and the temperatures range from 2 to 95 °C, differing for the specimen types. The data has been analyzed to yield differential enthalpy and entropy of adsorption, as well as the dependence of the relative vapor pressure on temperature at various constant moisture contents. The implications for the coefficient......PART I: In order to generate isosteric (constant mass) vapor pressure – temperature data (P-T data) for adsorbed pore water in hydrated cement paste, the Thermo Piestic Analysis system (the TPA system) described herein was developed. The TPA system generates high precision equilibrium isosteric P...

The vaporization enthalpies and vapor pressures of fatty acid methyl esters C18, C21 to C23, and C25 to C29 by correlation - gas chromatography

International Nuclear Information System (INIS)

Chickos, James S.; Zhao Hui; Nichols, Gary

2004-01-01

Vapor pressures and vaporization enthalpies for methyl heptadecanoate and methyl heneicosanoate to methyl octacosanoate exclusive of methyl tricosanoate are evaluated as a function of temperature over the temperature range T = 298.15-450 K by correlation gas chromatography. The results are generated by an extrapolative process using literature values for methyl tetradecanoate to methyl eicosanoate as standards. Relationships for calculating vapor pressures of the title compounds from T = 298.15 to 450 K are provided. Experimental fusion enthalpies are also reported for the methyl esters from methyl hexadecanoate to methyl octacosanoate excluding methyl tridecanoate. Vaporization enthalpies and fusion enthalpies adjusted for temperature to T = 298.15 K are combined to provide sublimation enthalpies. The results are compared to available literature values. A rationale for the linear relationship observed between enthalpies of vaporization and enthalpies of transfer from solution to the vapor is also provided

Estimation of formation enthalpies of vanadates by Born-Gaber cycle method

International Nuclear Information System (INIS)

Golovkin, B.G.

1993-01-01

Principle possibility of calculating Gibbs energy of ionic compound formation as a function of thermochemical radii of component ions of temperature and pressure is shown. Formula for determination of thermochemical radii of polyatomic ions is suggested. Enthalpies of formation of 81 vanadates were estimated with the use of Kapustinsky equation and Born-Gaber cycle

Enthalpy of mixing and heat of vaporization of ethyl acetate with benzene and toluene at 298.15 k and 308.15 k

OpenAIRE

K. L. Shivabasappa; P. Nirguna Babu; Y. Jagannadha Rao

2008-01-01

The present work was carried out in two phases. First, enthalpy of mixing was measured and then the heat of vaporization for the same mixtures was obtained. The data are useful in the design of separation equipments. From the various designs available for the experimental determination of enthalpy of mixing, and heat of vaporization, the apparatus was selected, modified and constructed. The apparatus of enthalpy of mixing was tested with a known system Benzene - i-Butyl Alcohol and the data o...

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

ArrayExpress update--trends in database growth and links to data analysis tools.

Science.gov (United States)

Rustici, Gabriella; Kolesnikov, Nikolay; Brandizi, Marco; Burdett, Tony; Dylag, Miroslaw; Emam, Ibrahim; Farne, Anna; Hastings, Emma; Ison, Jon; Keays, Maria; Kurbatova, Natalja; Malone, James; Mani, Roby; Mupo, Annalisa; Pedro Pereira, Rui; Pilicheva, Ekaterina; Rung, Johan; Sharma, Anjan; Tang, Y Amy; Ternent, Tobias; Tikhonov, Andrew; Welter, Danielle; Williams, Eleanor; Brazma, Alvis; Parkinson, Helen; Sarkans, Ugis

2013-01-01

The ArrayExpress Archive of Functional Genomics Data (http://www.ebi.ac.uk/arrayexpress) is one of three international functional genomics public data repositories, alongside the Gene Expression Omnibus at NCBI and the DDBJ Omics Archive, supporting peer-reviewed publications. It accepts data generated by sequencing or array-based technologies and currently contains data from almost a million assays, from over 30 000 experiments. The proportion of sequencing-based submissions has grown significantly over the last 2 years and has reached, in 2012, 15% of all new data. All data are available from ArrayExpress in MAGE-TAB format, which allows robust linking to data analysis and visualization tools, including Bioconductor and GenomeSpace. Additionally, R objects, for microarray data, and binary alignment format files, for sequencing data, have been generated for a significant proportion of ArrayExpress data.

Enthalpies of proton adsorption onto Bacillus licheniformis at 25, 37, 50, and 75 °C

Science.gov (United States)

Gorman-Lewis, Drew

2011-03-01

Understanding bacterial surface reactivity requires many different lines of investigation. Toward this end, we used isothermal titration calorimetry to measure heats of proton adsorption onto a Gram positive thermophile Bacillus licheniformis at 25, 37, 50, and 75 °C. Proton adsorption under all conditions exhibited exothermic heat production. Below pH 4.5, exothermic heats decreased as temperature increased above 37 °C; above pH 4.5, there was no significant difference in heats evolved at the temperatures investigated. Total proton uptake did not vary significantly with temperature. Site-specific enthalpies and entropies were calculated by applying a 4-site, non-electrostatic surface complexation model to the calorimetric data. Interpretation of site-specific enthalpies and entropies of proton adsorption for site L1, L2, and L4 are consistent with previous interpretations of phosphoryl, carboxyl, and hydroxyl/amine site-identities, respectively, and with previous calorimetric measurements of proton adsorption onto mesophilic species. Enthalpies and entropies for surface site L3 are not consistent with the commonly inferred phosphoryl site-identity and are more consistent with sulfhydryl functional groups. These results reveal intricacies of surface reactivity that are not detectable by other methods.

Short Pulsed Laser Methods for Velocimetry and Thermometry in High Enthalpy Facilities, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A suite of laser-based diagnostics is proposed to measure velocity and temperature simultaneously using unseeded techniques in high enthalpy flows relevant to...

The standard enthalpies of formation of L-asparagine and L-{alpha}-glutamine

Energy Technology Data Exchange (ETDEWEB)

Contineanu, Iulia, E-mail: icontineanu@yahoo.com [Institute of Physical Chemistry ' I.G. Murgulescu' , Spl. Independentei 202, Bucharest (Romania); Neacsu, Ana, E-mail: anna_matache@yahoo.com [Institute of Physical Chemistry ' I.G. Murgulescu' , Spl. Independentei 202, Bucharest (Romania); Perisanu, Stefan T., E-mail: stefan.perisanu@upb.ro [Laboratory of General Chemistry, Polytechnic University of Bucharest, str. Polizu nr. 1, Bucuresti (Romania)

2010-01-10

The energies of combustion of L-asparagine and L-{alpha}-glutamine were measured in a static bomb adiabatic calorimeter. Corrections were made for the heats due to the ignition of sample and for the nitric acid formation. The derived enthalpies of formation in solid state of asparagine monohydrate, nonhydrated asparagine and glutamine are respectively -1084.1 {+-} 3.0, -788.1 {+-} 4.7 and -834.3 {+-} 4.6 kJ mol{sup -1}. The data of enthalpy of formation are compared with the literature values and with estimated values by means of group additivity, using parameters recommended by Domalski and Hearing. The discrepancies between experimental and calculated values are explained by considering the number and strength of intermolecular hydrogen bonds. The dehydration of asparagine monohydrate and the possible melting of the three amino acids were investigated by means of DSC. Glutamine melts without considerable decomposition at about 182 {sup o}C, while asparagines decompose during the fusion process (208 {sup o}C).

Mass spectrometric study of thermodynamic properties of gaseous lead tellurates. Estimation of formation enthalpies of gaseous lead polonates

Energy Technology Data Exchange (ETDEWEB)

Shugurov, S.M., E-mail: s.shugurov@spbu.ru; Panin, A.I.; Lopatin, S.I.; Emelyanova, K.A.

2016-10-15

Gaseous reactions involving lead oxides, tellurium oxide and lead tellurates were studied by the Knudsen effusion mass spectrometry. Equilibrium constants and reaction enthalpies were evaluated. Structures, molecular parameters and thermodynamic functions of gaseous PbTeO{sub 3} and Pb{sub 2}TeO{sub 4} were calculated by quantum chemistry methods. The formation enthalpies Δ{sub f}H{sup 0} (298.15) = −294 ± 13 for gaseous PbTeO{sub 3} and Δ{sub f}H{sup 0} (298.15) = −499 ± 12 for gaseous Pb{sub 2}TeO{sub 4} were obtained. On the base of these results the formation enthalpies of gaseous PbPoO{sub 3} and Pb{sub 2}PoO{sub 4} were estimated as −249 ± 34 and −478 ± 38, respectively. - Highlights: • Gaseous lead tellurates PbTeO{sub 3}, Pb{sub 2}TeO{sub 4} were discovered. • Their thermodynamic properties were studied using both high temperature mass spectrometry and quantum chemistry computations. • The obtained data allows to predict the formation enthalpies of gaseous lead polonates PbPoO{sub 3}, Pb{sub 2}PoO{sub 4}.

Spacecraft Multiple Array Communication System Performance Analysis

Science.gov (United States)

Hwu, Shian U.; Desilva, Kanishka; Sham, Catherine C.

2010-01-01

The Communication Systems Simulation Laboratory (CSSL) at the NASA Johnson Space Center is tasked to perform spacecraft and ground network communication system simulations, design validation, and performance verification. The CSSL has developed simulation tools that model spacecraft communication systems and the space and ground environment in which the tools operate. In this paper, a spacecraft communication system with multiple arrays is simulated. Multiple array combined technique is used to increase the radio frequency coverage and data rate performance. The technique is to achieve phase coherence among the phased arrays to combine the signals at the targeting receiver constructively. There are many technical challenges in spacecraft integration with a high transmit power communication system. The array combining technique can improve the communication system data rate and coverage performances without increasing the system transmit power requirements. Example simulation results indicate significant performance improvement can be achieved with phase coherence implementation.

Enthalpies of solution of N,N,N',N'-tetramethylurea in amides, dimethylsulphoxide, and acetone at 298.15 K

International Nuclear Information System (INIS)

Ivanov, Evgeniy V.; Smirnov, Valeriy I.

2008-01-01

The enthalpies of solution Δ sol H m m were determined for N,N,N',N'-tetramethylurea in formamide, N-methylformamide, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulphoxide, and acetone. Measurements were made at 298.15 K and molalities m = (0.004 to 0.031) mol . kg -1 with a precise isoperibol ampoule-type calorimeter. Standard enthalpies of solution Δ sol H m 0 and transfer Δ tr H m 0 from one solvent to another were computed. The enthalpies of solution of the solute in the hydrogen-non-bonding media were found to be endothermic and weak depending on the nature of methylation in a solvent molecule. It was concluded that the solvent proton-donor ability and existing steric hindrances for hydrogen bonding and other intermolecular interactions play the key role in solvation of tetramethylurea

Experimental investigation of the enthalpy and mass flow distribution between subchannels in a BWR cluster geometry (PELCO-S)

International Nuclear Information System (INIS)

Herkenrath, H.; Hufschmidt, W.

1979-01-01

Experiments based on the subchannel isokinetic technique have been carried out at the JRC of the European Community at Ispra, using a purposely designed 16-rod test section, simulating in a rather accurate way a typical BWR geometry. The adopted system allows the simultaneous determination of mass flow and enthalpy, at the end of the bundle active length, in four characteristic subchannels of the 16-rod lattice. The results show some pronounced flow and enthalpy variations within the bundle, not accurately taken into account by current subchannel codes, such as COBRA-3C. In particular low values both in mass flow and enthalpy have been found in corner subchannel, in disagreement with code predictions, but confirming previous General Electric experiments carried out in a 9-rod test section. This report deals only with the experimental procedure and the results

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.

Vapor pressures and vaporization enthalpy of (−) α-bisabolol and (dl) menthol by correlation gas chromatography

International Nuclear Information System (INIS)

Keating, Leasa; Harris, Harold H.; Chickos, James S.

2017-01-01

Highlights: • The vaporization enthalpy and vapor pressure of (−) α-bisabolol and (dl)-menthol have been measured as a function of temperature. • Vapor pressures, vaporization enthalpies and boiling temperatures have been compared to available literature data. • Vapor pressures of (l)-menthol are compared to (dl)-menthol. - Abstract: The vapor pressures and vaporization enthalpies of (−) α-bisabolol and (dl)-menthol, two GRAS chemicals (generally recognized as safe) are evaluated by correlation gas chromatography using a series of saturated primary alcohols as standards. Vaporization enthalpies of (96.6 ± 2.4) and (74.2 ± 2.8) kJ mol −1 and vapor pressures of p/Pa = (0.020 ± 0.003) and (4.5 ± 0.44) were evaluated at T = 298.15 K for (−) α-bisabolol and (dl)-menthol, respectively, and compared to literature values. The vapor pressures of both compounds from T = (298.15 to 500) K have been derived from correlations using vapor pressures of a series of 1-alkanols and corresponding gas chromatographic retention times at 10 K intervals. The results were fit to a second order polynomial. Calculated normal boiling temperatures of T B = (574.8 and 492.7) K are calculated for (−) α-bisabolol and (dl)-menthol, respectively. A normal boiling temperature of T B = (485.2, and 489.7) K has previously been reported for (dl)-menthol. Vapor pressures for both (l)-menthol and (dl)-menthol from a previous study and (dl)-menthol from this study are compared with literature values.

Energetic studies of urea derivatives: Standard molar enthalpy of formation of 3,4,4'-trichlorocarbanilide

Energy Technology Data Exchange (ETDEWEB)

Ribeiro da Silva, Maria das Dores M.C. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Ribeiro da Silva, Manuel A.V., E-mail: risilva@fc.up.p [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Freitas, Vera L.S. [Centro de Investigacao em Quimica, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto (Portugal); Roux, Maria Victoria; Jimenez, Pilar; Davalos, Juan Z. [Instituto de Quimica Fisica ' Rocasolano' , C.S.I.C., Serrano, 119, E-28006 Madrid (Spain); Cabildo, Pilar; Claramunt, Rosa M. [Departamento de Quimica Organica y Bio-Organica, Facultad de Ciencias, UNED, Senda del Rey, 9, E-28040 Madrid (Spain); Pinilla, Elena; Rosario Torres, M. [Departamento de Quimica Inorganica I, Laboratorio de Difraccion de Rayos X, Facultad de Ciencias Quimicas, E-28040 Madrid (Spain); Elguero, Jose [Instituto de Quimica Medica, C.S.I.C., Juan de la Cierva, 3, E-28006 Madrid (Spain)

2010-04-15

Thermochemical and thermophysical studies have been carried out for crystalline 3,4,4'-trichlorocarbanilide. The standard (p{sup o} = 0.1 MPa) molar enthalpy of formation, at T = 298.15 K, for the crystalline 3,4,4'-trichlorocarbanilide (TCC) was experimentally determined using rotating-bomb combustion calorimetry, as -(234.6 +- 8.3) kJ . mol{sup -1}. The standard enthalpy of sublimation, at the reference temperature of 298.15 K, was measured by the vacuum drop microcalorimetric technique, using a High Temperature Calvet Microcalorimeter as (182.1 +- 1.7) kJ . mol{sup -1}. These two thermochemical parameters yielded the standard molar enthalpy of formation of the studied compound, in the gaseous phase, at T = 298.15 K, as -(52.5 +- 8.5) kJ . mol{sup -1}. This parameter was also calculated by computational thermochemistry at M05-2X/6-311++G** and B3LYP/6-311++G(3df, 2p) levels, with a deviation less than 4.5 kJ . mol{sup -1} from experimental value. Moreover, the thermophysical study was made by differential scanning calorimetry, DSC, over the temperature interval between T = 263 K and its onset fusion temperature, T = (527.5 +- 0.4) K. A solid-solid phase transition was found at T = (428 +- 1) K, with the enthalpy of transition of (6.1 +- 0.1) kJ . mol{sup -1}. The X-ray crystal structure of TCC was determined and the three-centred N-H...O=C hydrogen bonds present analyzed.

Standard enthalpy, entropy and Gibbs free energy of formation of «A» type carbonate phosphocalcium hydroxyapatites

International Nuclear Information System (INIS)

Jebri, Sonia; Khattech, Ismail; Jemal, Mohamed

2017-01-01

Highlights: • A-type carbonate hydroxyapatites with 0 ⩽ x ⩽ 1 were prepared and characterized by DRX, IR spectroscopy and CHN analysis. • The heat of solution was measured in 9 wt% HNO 3 using an isoperibol calorimeter. • The standard enthalpy of formation was determined by thermochemical cycle. • Gibbs free energy has been deduced by estimating standard entropy of formation. • Carbonatation increases the stability till x = 0.6 mol. - Abstract: « A » type carbonate phosphocalcium hydroxyapatites having the general formula Ca 10 (PO 4 ) 6 (OH) (2-2x) (CO 3 ) x with 0 ⩽ x ⩽ 1, were prepared by solid gas reaction in the temperature range of 700–1000 °C. The obtained materials were characterized by X-ray diffraction and infrared spectroscopy. The carbonate content has been determined by C–H–N analysis. The heat of solution of these products was measured at T = 298 K in 9 wt% nitric acid solution using an isoperibol calorimeter. A thermochemical cycle was proposed and complementary experiences were performed in order to access to the standard enthalpies of formation of these phosphates. The results were compared to those previously obtained on apatites containing strontium and barium and show a decrease with the carbonate amount introduced in the lattice. This quantity becomes more negative as the ratio of substitution increases. Estimation of the entropy of formation allowed the determination of standard Gibbs free energy of formation of these compounds. The study showed that the substitution of hydroxyl by carbonate ions contributes to the stabilisation of the apatite structure.

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

Experimental-numerical study of heat flow in deep low-enthalpy geothermal conditions

NARCIS (Netherlands)

Saeid, S.; Al-Khoury, R.; Nick, H.M.; Barends, F.

2014-01-01

This paper presents an intensive experimental-numerical study of heat flow in a saturated porous domain. A temperature and a flow rate range compared to that existing in a typical deep low-enthalpy hydrothermal system is studied. Two main issues are examined: the effect of fluid density and

Standard molar enthalpies of formation of 2-chloroquinoline, 4-chloroquinoline, 6-chloroquinoline and 4,7-dichloroquinoline by rotating-bomb calorimetry

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Matos, Maria Agostinha R.; Amaral, Luisa M.P.F.

2006-01-01

The standard (p o =0.1MPa) molar enthalpies of combustion, Δ c H m - bar , for crystalline 2-, 4-, 6-chloroquinoline and 4,7-dichloroquinoline were determined at the temperature 298.15K using a rotating-bomb combustion calorimeter. The standard molar enthalpies of sublimation, Δ cr g H m o , at T= 298.15K, were determined by Calvet microcalorimetry. The results were as follows: -Δ c H m o (cr)/(kJ.mol -1 )Δ cr g H m o /(kJ.mol -1 )2-Chloroquinoline4492.5+/-1.684.3+/-2.64-Chloroquinoline4508.4 +/ -1.678.6+/-1.76-Chloroquinoline4508.2+/-1.680.8+/-1.94,7-Dichloroquinoline 4353.3+/-1.389.5+/-2.3 These values were used to derive the standard molar enthalpies of formation of the compounds in their crystalline and gaseous phases, respectively. The derived standard molar enthalpies of formation, in the gaseous state, are analysed in terms of enthalpic increments and interpreted in terms of molecular structure

Seismic Background Noise Analysis of BRTR (PS-43) Array

Science.gov (United States)

Ezgi Bakir, Mahmure; Meral Ozel, Nurcan; Umut Semin, Korhan

2015-04-01

The seismic background noise variation of BRTR array, composed of two sub arrays located in Ankara and in Ankara-Keskin, has been investigated by calculating Power Spectral Density and Probability Density Functions for seasonal and diurnal noise variations between 2005 and 2011. PSDs were computed within the frequency range of 100 s - 10 Hz. The results show us a little change in noise conditions in terms of time and location. Especially, noise level changes were observed at 3-5 Hz in diurnal variations at Keskin array and there is a 5-7 dB difference in day and night time in cultural noise band (1-10 Hz). On the other hand, noise levels of medium period array is high in 1-2 Hz frequency rather than short period array. High noise levels were observed in daily working times when we compare it to night-time in cultural noise band. The seasonal background noise variation at both sites also shows very similar properties to each other. Since these stations are borehole instruments and away from the coasts, we saw a small change in noise levels caused by microseism. Comparison between Keskin short period array and Ankara medium period array show us Keskin array is quiter than Ankara array.

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

OpenAIRE

Berta ALVAREZ PENEDO; Sandra FORSTNER; Alexandru RUSU

2016-01-01

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,

The Role of Structural Enthalpy in Spherical Nucleic Acid Hybridization.

Science.gov (United States)

Fong, Lam-Kiu; Wang, Ziwei; Schatz, George C; Luijten, Erik; Mirkin, Chad A

2018-05-23

DNA hybridization onto DNA-functionalized nanoparticle surfaces (e.g., in the form of a spherical nucleic acid (SNA)) is known to be enhanced relative to hybridization free in solution. Surprisingly, via isothermal titration calorimetry, we reveal that this enhancement is enthalpically, as opposed to entropically, dominated by ∼20 kcal/mol. Coarse-grained molecular dynamics simulations suggest that the observed enthalpic enhancement results from structurally confining the DNA on the nanoparticle surface and preventing it from adopting enthalpically unfavorable conformations like those observed in the solution case. The idea that structural confinement leads to the formation of energetically more stable duplexes is evaluated by decreasing the degree of confinement a duplex experiences on the nanoparticle surface. Both experiment and simulation confirm that when the surface-bound duplex is less confined, i.e., at lower DNA surface density or at greater distance from the nanoparticle surface, its enthalpy of formation approaches the less favorable enthalpy of duplex formation for the linear strand in solution. This work provides insight into one of the most important and enabling properties of SNAs and will inform the design of materials that rely on the thermodynamics of hybridization onto DNA-functionalized surfaces, including diagnostic probes and therapeutic agents.

A Simple Experiment for Determining Vapor Pressure and Enthalpy of Vaporization of Water.

Science.gov (United States)

Levinson, Gerald S.

1982-01-01

Laboratory procedures, calculations, and sample results are described for a freshman chemistry experiment in which the Clausius-Clapeyron equation is introduced as a means of describing the variation of vapor pressure with temperature and for determining enthalpy of vaporization. (Author/SK)

Enthalpy and high temperature relaxation kinetics of stable vapor-deposited glasses of toluene

International Nuclear Information System (INIS)

Bhattacharya, Deepanjan; Sadtchenko, Vlad

2014-01-01

Stable non-crystalline toluene films of micrometer and nanometer thicknesses were grown by vapor deposition at distinct rates and probed by fast scanning calorimetry. Fast scanning calorimetry is shown to be extremely sensitive to the structure of the vapor-deposited phase and was used to characterize simultaneously its kinetic stability and its thermodynamic properties. According to our analysis, transformation of vapor-deposited samples of toluene during heating with rates in excess 10 5 K s −1 follows the zero-order kinetics. The transformation rate correlates strongly with the initial enthalpy of the sample, which increases with the deposition rate according to sub-linear law. Analysis of the transformation kinetics of vapor-deposited toluene films of various thicknesses reveal a sudden increase in the transformation rate for films thinner than 250 nm. The change in kinetics seems to correlate with the surface roughness scale of the substrate. The implications of these findings for the formation mechanism and structure of vapor-deposited stable glasses are discussed

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.

Discrimination of honeys using colorimetric sensor arrays, sensory analysis and gas chromatography techniques.

Science.gov (United States)

Tahir, Haroon Elrasheid; Xiaobo, Zou; Xiaowei, Huang; Jiyong, Shi; Mariod, Abdalbasit Adam

2016-09-01

Aroma profiles of six honey varieties of different botanical origins were investigated using colorimetric sensor array, gas chromatography-mass spectrometry (GC-MS) and descriptive sensory analysis. Fifty-eight aroma compounds were identified, including 2 norisoprenoids, 5 hydrocarbons, 4 terpenes, 6 phenols, 7 ketones, 9 acids, 12 aldehydes and 13 alcohols. Twenty abundant or active compounds were chosen as key compounds to characterize honey aroma. Discrimination of the honeys was subsequently implemented using multivariate analysis, including hierarchical clustering analysis (HCA) and principal component analysis (PCA). Honeys of the same botanical origin were grouped together in the PCA score plot and HCA dendrogram. SPME-GC/MS and colorimetric sensor array were able to discriminate the honeys effectively with the advantages of being rapid, simple and low-cost. Moreover, partial least squares regression (PLSR) was applied to indicate the relationship between sensory descriptors and aroma compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Field tests for the comparative evaluation of heat and enthalpy exchangers in compact ventilation units; Feldvergleich von Waerme- und Enthalpieuebertragern in Kompakt-Lueftungsgeraeten - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Frei, B.

2007-07-01

In an efficiency review on low energy buildings promoted by the Swiss Federal Office of Energy, low air humidity has been measured during thousands of annual hours. Modern compact ventilation units are being increasingly offered with transmission of heat and moisture. One possibility to raise the air humidity level is an enthalpy exchanger with steam-permeable membranes. With an enthalpy exchanger you can not only recover heat but also a good part of the humidity of the return air. In a comparative field study alternate applications with enthalpy or heat exchangers have been analysed at four different locations. Also calculations have been made to estimate how a rotating heat exchanger with ion-exchange resin would have performed. The comparative field study has shown that the enthalpy exchanger is able to raise the humidity level. Conditions for this are internal humidity loads, balanced air volume rates which correspond to occupancy as well as low leakages of the ventilation unit. Over-moistening due to the system with enthalpy exchanger was not found. The measurements have been affected by a sequence of winter months which have been partially warmer than usual. Otherwise the difference between enthalpy and heat exchangers would have been more significant. (author)

Revision of standard molar enthalpies of formation of glycine and L-alanine in the gaseous phase on the basis of theoretical calculations

International Nuclear Information System (INIS)

Dorofeeva, Olga V.; Ryzhova, Oxana N.

2009-01-01

The standard molar enthalpies of formation of urea, glycine, and L-alanine in the gaseous phase at 298.15 K were calculated by the high-level Gaussian-3X method. The agreement with the available experimental data is very good for urea and glycine and, thus, supports the high accuracy of calculated values. A significant discrepancy between theoretical and experimental enthalpy of formation values for L-alanine provides a reason to reconsider the experimental data previously used to derive the standard molar enthalpy of formation of L-alanine in the gaseous phase at 298.15 K. To obtain a more reliable value of enthalpy of sublimation at 298.15 K, the heat capacity values of gaseous L-alanine were calculated by standard statistical thermodynamics formulae using molecular parameters determined from B3LYP/cc-pVTZ calculations. With the obtained value of C p,m 0 (L-alanine, g, 298.15 K) = 112.6 ± 4.0 J . K -1 . mol -1 the original published experimental values of enthalpy of sublimation of L-alanine were readjusted to the reference temperature: Δ cr g H m (L-alanine, 298.15 K) = 135.2 ± 2.0 kJ . mol -1 . This value, together with the experimental enthalpy of formation of solid L-alanine, Δ f H m 0 (L-alanine, cr, 298.15 K) = -560.0 ± 1.0 kJ . mol -1 [S.N. Ngauv, R. Sabbah, M. Laffitte, Thermochim. Acta 20 (1977) 371-380; I. Contineanu, D.I. Marchidan, Rev. Roum. Chim. 29 (1984) 43-48], gives a new value for the enthalpy of formation of L-alanine in the gaseous phase, Δ f H m 0 (L-alanine, g, 298.15 K) = -424.8 ± 2.0 kJ . mol -1 , which is in good agreement with our theoretical G3X result, -427.6 ± 4.0 kJ . mol -1 . The same procedure for glycine allowed us to improve the literature value of the enthalpy of formation for this compound, Δ f H m 0 (glycine, g, 298.15 K) = -393.7 ± 1.5 kJ . mol -1 . As a result a set of self-consistent thermochemical data for glycine and L-alanine is proposed

Enthalpy and interfacial free energy changes of water capillary condensed in mesoporous silica, MCM-41 and SBA-15.

Science.gov (United States)

Kittaka, Shigeharu; Ishimaru, Shinji; Kuranishi, Miki; Matsuda, Tomoko; Yamaguchi, Toshio

2006-07-21

The effect of confinement on the solid-liquid phase transitions of water was studied by using DSC and FT-IR measurements. Enthalpy changes upon melting of frozen water in MCM-41 and SBA-15 were determined as a function of pore size and found to decrease with decreasing pore size. The melting point also decreased almost monotonically with a decrease in pore size. Analysis of the Gibbs-Thomson relation on the basis of the thermodynamic data showed that there were two stages of interfacial free energy change after the constant region, i.e., below a pore size of 6.0 nm: a gradual decrease down to 3.4 nm and another decrease after a small jump upward. This fact demonstrates that the simple Gibbs-Thomson relation, i.e., a linear relation between the melting point change and the inverse pore size, is limited to the range not far from the melting point of bulk water. FT-IR measurements suggest that the decrease in enthalpy change and interfacial free energy change with decreasing pore size reflect the similarity of the structures of both liquid and solid phases of water in smaller pores at lower temperatures.

Vapor pressures and enthalpies of vaporization of a series of 1- and 2-halogenated naphthalenes

International Nuclear Information System (INIS)

Verevkin, Sergey P.

2003-01-01

Molar enthalpies of vaporization, Δ l g H m 0 , of 1-methyl-naphthalene, 1-chloro-napthalene, 2-chloro-naphthalene, 1-bromo-naphthalene, 2-bromo-naphthalene, and 1-iodo-naphthalene, as well as molar enthalpies of sublimation, Δ s g H m 0 , of 2-chloro-naphthalene and 2-bromo-naphthalene have been obtained from the temperature dependence of the vapor pressure determined with the transpiration method. These values and the correlation gas-chromatography method, based on the Kovat's index, have been used to determine Δ l g H m 0 and Δ s g H m 0 of 2-iodo-naphthalene. Results obtained in this work have been compared with those from the literature and found consistent

Enthalpies of Dissolution of Crystalline Naproxen Sodium in Water and Potassium Hydroxide Aqueous Solutions at 298 K

Science.gov (United States)

Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Bychkova, S. A.; Volkov, A. V.; Skvortsov, I. A.

2018-03-01

The enthalpies of dissolution of crystalline naproxen sodium in water and aqueous solutions of KOH at 298.15 K are measured by direct calorimetric means in a wide range of concentrations. The acid-base properties of naproxen sodium at ionic strength I 0 and I = 0.1 (KNO3) and a temperature of 298.15 K are studied by spectrophotometric means. The concentration and thermodynamic dissociation constants are determined. The standard enthalpies of the formation of naproxen sodium and the products of its dissociation in aqueous solution are calculated.

Investigation on the transient enthalpy of coal combustion

Energy Technology Data Exchange (ETDEWEB)

Fu, Pei-fang; Wang, Na; Yu, Bo; Zhang, Bin; Liu, Yang; Zhou, Huai-chun [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion

2013-07-01

The transient enthalpy ({Delta}h) of coal/char combustion of the three different coals (including anthracite, bituminous, and lignite) during the process of combustion is determined as a function of burn-off degree by using thermo-gravimetric-differential scanning calorimeter (TG-DSC) simultaneous thermal analyzer, and The error of determining calorific values of coals/chars is less 5% compared the results of TG-DSC with that of an automatic isoperibol calorimeter. It is found that In the initial stage, all the {Delta}h of coals are greater than that of the char pyrolysized from parent coal for many of volatiles contained more a great deal of heat per unit mass oxidized at low temperature, it also imply that coal is more easily ignited than char corresponded; And in the middle stage, all the {Delta}h of coals is lower than that of the char pyrolysized, so the pyrolysized char oxidation can supply much more of thermo-energy per unit mass. {Delta}h are almost a constant when the burn-off degree is equal to between 0.35/0.15 and 0.95/0.85 for ZCY bituminous coal/char and JWY anthracite/char, between 0.35/0.35 and 0.75/0.9 for SLH lignite/char; In the later stage, the {Delta}h of the coal/char decreased with the burn-off degree, it imply that the activity of the coal/char decreases. Therefore, coal pyrolysis changes not only the structure of char, but also the property of release heat; the transient enthalpy of coal/char combustion has been in change with the burn-out degree.

Transient three-dimensional thermal-hydraulic analysis of nuclear reactor fuel rod arrays: general equations and numerical scheme

International Nuclear Information System (INIS)

Wnek, W.J.; Ramshaw, J.D.; Trapp, J.A.; Hughes, E.D.; Solbrig, C.W.

1975-11-01

A mathematical model and a numerical solution scheme for thermal-hydraulic analysis of fuel rod arrays are given. The model alleviates the two major deficiencies associated with existing rod array analysis models, that of a correct transverse momentum equation and the capability of handling reversing and circulatory flows. Possible applications of the model include steady state and transient subchannel calculations as well as analysis of flows in heat exchangers, other engineering equipment, and porous media

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.

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.

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,

Efficient Analysis of Systems Biology Markup Language Models of Cellular Populations Using Arrays.

Science.gov (United States)

Watanabe, Leandro; Myers, Chris J

2016-08-19

The Systems Biology Markup Language (SBML) has been widely used for modeling biological systems. Although SBML has been successful in representing a wide variety of biochemical models, the core standard lacks the structure for representing large complex regular systems in a standard way, such as whole-cell and cellular population models. These models require a large number of variables to represent certain aspects of these types of models, such as the chromosome in the whole-cell model and the many identical cell models in a cellular population. While SBML core is not designed to handle these types of models efficiently, the proposed SBML arrays package can represent such regular structures more easily. However, in order to take full advantage of the package, analysis needs to be aware of the arrays structure. When expanding the array constructs within a model, some of the advantages of using arrays are lost. This paper describes a more efficient way to simulate arrayed models. To illustrate the proposed method, this paper uses a population of repressilator and genetic toggle switch circuits as examples. Results show that there are memory benefits using this approach with a modest cost in runtime.

A continuous flow microfluidic calorimeter: 3-D numerical modeling with aqueous reactants

International Nuclear Information System (INIS)

Sen, Mehmet A.; Kowalski, Gregory J.; Fiering, Jason; Larson, Dale

2015-01-01

Highlights: • A co-flow microreactor is modeled in flow, reaction/diffusion, and thermal domains. • Analysis shows how arrayed temperature sensors can provide enthalpy of reaction. • Optical plasmonic temperature sensors could be arrayed suitably for calorimetry. • The reactor studied has a volume of 25 nL. - Abstract: A computational analysis of the reacting flow field, species diffusion and heat transfer processes with thermal boundary layer effects in a microchannel reactor with a coflow configuration was performed. Two parallel adjacent streams of aqueous reactants flow along a wide, shallow, enclosed channel in contact with a substrate, which is affixed to a temperature controlled plate. The Fluent computational fluid dynamics package solved the Navier–Stokes, mass transport and energy equations. The energy model, including the enthalpy of reaction as a nonuniform heat source, was validated by calculating the energy balance at several control volumes in the microchannel. Analysis reveals that the temperature is nearly uniform across the channel thickness, in the direction normal to the substrate surface; hence, measurements made by sensors at or near the surface are representative of the average temperature. Additionally, modeling the channel with a glass substrate and a silicone cover shows that heat transfer is predominantly due to the glass substrate. Finally, using the numerical results, we suggest that a microcalorimeter could be based on this configuration, and that temperature sensors such as optical nanohole array sensors could have sufficient spatial resolution to determine enthalpy of reaction

A continuous flow microfluidic calorimeter: 3-D numerical modeling with aqueous reactants

Energy Technology Data Exchange (ETDEWEB)

Sen, Mehmet A., E-mail: mehmet.sen@mathworks.com [Northeastern University, Department of Mechanical and Industrial Engineering, 360 Hungtington Avenue, 334 Snell Engineering Center, Boston, MA 02115 (United States); Kowalski, Gregory J., E-mail: gkowal@coe.neu.edu [Northeastern University, Department of Mechanical and Industrial Engineering, 360 Hungtington Avenue, 334 Snell Engineering Center, Boston, MA 02115 (United States); Fiering, Jason, E-mail: jfiering@draper.com [Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139 (United States); Larson, Dale, E-mail: dlarson@draper.com [Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139 (United States)

2015-03-10

Highlights: • A co-flow microreactor is modeled in flow, reaction/diffusion, and thermal domains. • Analysis shows how arrayed temperature sensors can provide enthalpy of reaction. • Optical plasmonic temperature sensors could be arrayed suitably for calorimetry. • The reactor studied has a volume of 25 nL. - Abstract: A computational analysis of the reacting flow field, species diffusion and heat transfer processes with thermal boundary layer effects in a microchannel reactor with a coflow configuration was performed. Two parallel adjacent streams of aqueous reactants flow along a wide, shallow, enclosed channel in contact with a substrate, which is affixed to a temperature controlled plate. The Fluent computational fluid dynamics package solved the Navier–Stokes, mass transport and energy equations. The energy model, including the enthalpy of reaction as a nonuniform heat source, was validated by calculating the energy balance at several control volumes in the microchannel. Analysis reveals that the temperature is nearly uniform across the channel thickness, in the direction normal to the substrate surface; hence, measurements made by sensors at or near the surface are representative of the average temperature. Additionally, modeling the channel with a glass substrate and a silicone cover shows that heat transfer is predominantly due to the glass substrate. Finally, using the numerical results, we suggest that a microcalorimeter could be based on this configuration, and that temperature sensors such as optical nanohole array sensors could have sufficient spatial resolution to determine enthalpy of reaction.

Determination of molar enthalpy of sublimation in case of orotic acid as obtained from experimental and computational data

Science.gov (United States)

Marochkin, Ilya I.; Altova, Ekaterina P.; Chilingarov, Norbert S.; Vilkova, Anna L.; Shishkov, Igor F.

2018-03-01

Saturated vapor pressure, ln(p/Pa) = (-21316 ± 511)/(T/K)+(41.64 ± 0.11), and enthalpy of sublimation of orotic acid, Δsub Hm0 (Tm) = 177 ± 4 kJ/mol, were determined by means of Knudsen effusion mass spectrometry in the temperature range of 423÷493 K. The computational approaches supported the experimental results reported. The theoretical estimation of the gas-phase enthalpy of formation for orotic acid was done with different working reactions used.

Vapor pressures and enthalpies of vaporization of a series of the linear aliphatic aldehydes

Czech Academy of Sciences Publication Activity Database

Verevkin, S. P.; Krasnykh, E. L.; Vasiltsova, T. V.; Koutek, Bohumír; Doubský, Jan; Heintz, A.

2003-01-01

Roč. 206, - (2003), s. 331-339 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z4055905 Keywords : aldehydes * vapor pressure * enthalpy of vaporization Subject RIV: CC - Organic Chemistry Impact factor: 1.165, year: 2003

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

OpenAIRE

Vasilios Alexiades; David Autrique

2010-01-01

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 th...

On determination of enthalpies of complex formation reactions by means of temperature coefficient of complexing degree

International Nuclear Information System (INIS)

Povar, I.G.

1995-01-01

Equations describing the relation between temperature coefficient of ∂lnα/∂T complexing degree and the sum of changes in the enthalpy of complex formation of the composition M m L n δH mn multiplied by the weight coefficients k mm , are presented. A method to determine changes in the enthalpy of certain ΔH mm reactions from ∂lnα/∂T derivatives has been suggested. The best approximating equation from lnα/(T) dependence has been found. Errors of thus determined δH mm values are estimated and the results of calculation experiment for the system In 3+ -F - are provided. 10 refs., 2 figs., 3 tabs

Noise analysis and performance of a selfscanned linear InSb detector array

International Nuclear Information System (INIS)

Finger, G.; Meyer, M.; Moorwood, A.F.M.

1987-01-01

A noise model for detectors operated in the capacitive discharge mode is presented. It is used to analyze the noise performance of the ESO nested timing readout technique applied to a linear 32-element InSb array which is multiplexed by a silicon switched-FET shift register. Analysis shows that KTC noise of the videoline is the major noise contribution; it can be eliminated by weighted double-correlated sampling. Best noise performance of this array is achieved at the smallest possible reverse bias voltage (not more than 20 mV) whereas excess noise is observed at higher reverse bias voltages. 5 references

The relation between inversion enthalpy and adsorption parameters for an activated carbon in aqueous Pb2+ solutions

International Nuclear Information System (INIS)

Giraldo, Liliana; Moreno, Juan Carlos

2006-01-01

We report the preparation of an activated carbon obtained by impregnation of mineral carbon samples with a phosphoric acid solution (50%).The obtained material, exhibits a superficial area of 586 m 2 .g -1 and a total pore volume of 0.37 cm 3 g -1 . With respect to the chemical properties, the activated carbon shows an increased number of acidic sites (0.92 meq g -l ) compared to basic sites (0.63 meq g-1) which yields a material with almost neutral characteristics (PHpzc: 7.4). At a pH: 4.0 the amount of Pb 2 + absorbed and the immersion enthalpy values for the activated carbon reached a maximum with values of 15.7 mg -1 y 27.6 Jg -1 respectively. It was established that similar behaviour occurs for the two properties, absorption and immersion enthalpy, as a function of pH. In addition, a second order function that relates the adsorption constant and immersion enthalpy, and the adsorption constant and pH of the solution are presented

The relation between immersion enthalpy and adsorption parameters for an activated carbon in aqueous Pb2+solutions

International Nuclear Information System (INIS)

Girado, Liliana; Moreno, Juan Carlos

2006-01-01

We report the preparation of an activated carbon obtained by impregnation of mineral carbon samples with phosphoric acid solution (50%). the obtained material, exhibits a superficial area of 586 m 2 .g -1 and a total pore volume of 0,37 cm 3 g -1 . with respect to the chemical properties, the activated carbon shows an increased number of acidic sites (0,92 meq g -1 ) compared to basic sites (0,63 meq g -1 ) which yields a material with almost neutral characteristics (pH p zc: 7,4). At a pH: 4.0 the amount of pb2+ absorbed and the immersion enthalpy values for the activated carbon reached maxim with values of 15.7 mg -1 y 27,6 Jg -1 respectively. it was established that similar behavior occurs for the two properties, absorption and immersion enthalpy, as a function of pH. in addition, a second order function that relates the adsorption constant and immersion enthalpy, and the adsorption constant and ph of the solution are presented

Standard Test Method for Calculation of Stagnation Enthalpy from Heat Transfer Theory and Experimental Measurements of Stagnation-Point Heat Transfer and Pressure

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

1.1 This test method covers the calculation from heat transfer theory of the stagnation enthalpy from experimental measurements of the stagnation-point heat transfer and stagnation pressure. 1.2 Advantages 1.2.1 A value of stagnation enthalpy can be obtained at the location in the stream where the model is tested. This value gives a consistent set of data, along with heat transfer and stagnation pressure, for ablation computations. 1.2.2 This computation of stagnation enthalpy does not require the measurement of any arc heater parameters. 1.3 Limitations and ConsiderationsThere are many factors that may contribute to an error using this type of approach to calculate stagnation enthalpy, including: 1.3.1 TurbulenceThe turbulence generated by adding energy to the stream may cause deviation from the laminar equilibrium heat transfer theory. 1.3.2 Equilibrium, Nonequilibrium, or Frozen State of GasThe reaction rates and expansions may be such that the gas is far from thermodynamic equilibrium. 1.3.3 Noncat...

Prediction of the enthalpies of vaporization for room-temperature ionic liquids: Correlations and a substitution-based additive scheme

International Nuclear Information System (INIS)

Kabo, Gennady J.; Paulechka, Yauheni U.; Zaitsau, Dzmitry H.; Firaha, Alena S.

2015-01-01

Highlights: • The available literature data on Δ l g H for ionic liquids were analyzed. • Correlation equations for Δ l g H were derived using symbolic regression. • A substitution-based incremental scheme for Δ l g H was developed. • The proposed scheme has an advantage over the existing predictive procedures. - Abstract: The literature data on the enthalpies of vaporization for aprotic ionic liquids (ILs) published by the end of May 2014 were analyzed and the most reliable Δ l g H m values were derived for 68 ILs. The selected enthalpies of vaporization were correlated with density and surface tension using symbolic regression and a number of effective correlation equations were proposed. The substitution-based incremental scheme for prediction of the enthalpies of vaporization of imidazolium, pyridinium and pyrrolidinium ILs was developed. The standard error of the regression for the developed scheme is significantly lower than that for the atom-based group-contribution schemes proposed earlier

Prediction of the vapor pressure and vaporization enthalpy of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids.

Science.gov (United States)

Diedenhofen, Michael; Klamt, Andreas; Marsh, Kenneth; Schäfer, Ansgar

2007-09-07

The vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids have been predicted with two different approaches using the COSMO-RS method and quantum chemical gas phase calculations. While the calculated enthalpies are in good agreement with the experimental data, COSMO-RS seems to underestimate the vapor pressures by roughly 0.5-4 log units dependent on the IL and approach used.

Numerical analysis of natural convection and radiation heat transfer from various shaped thin fin-arrays placed on a horizontal plate-a conjugate analysis

International Nuclear Information System (INIS)

Dogan, M.; Sivrioglu, Mecit; Yılmaz, Onder

2014-01-01

Highlights: • Optimum fin shape is determined for natural convection and radiation heat transfer. • Fin array with the optimum shape has a much greater average heat transfer coefficient. • The most important factors affecting the heat transfer coefficient are determined. - Abstract: Steady state natural convection and radiation heat transfer from various shaped thin fin-arrays on a horizontal base plate has been numerically investigated. A conjugate analysis has been carried out in which the conservation equations of mass, momentum and energy for the fluid in the two fin enclosure are solved together with the heat conduction equation in the fin and the base plate. Heat transfer by radiation is also considered in analysis. The heat transfer coefficient has been determined for each of the fin array considered in the present study at the same base and the same total area. The results of the analysis show that there are some important geometrical factors affecting the design of fin arrays. Taking into consideration these factors, an optimum fin shape that yields the highest average heat transfer coefficient has been determined

Fiber-optic microsphere-based antibody array for the analysis of inflammatory cytokines in saliva.

Science.gov (United States)

Blicharz, Timothy M; Siqueira, Walter L; Helmerhorst, Eva J; Oppenheim, Frank G; Wexler, Philip J; Little, Frédéric F; Walt, David R

2009-03-15

Antibody microarrays have emerged as useful tools for high-throughput protein analysis and candidate biomarker screening. We describe here the development of a multiplexed microsphere-based antibody array capable of simultaneously measuring 10 inflammatory protein mediators. Cytokine-capture microspheres were fabricated by covalently coupling monoclonal antibodies specific for cytokines of interest to fluorescently encoded 3.1 microm polymer microspheres. An optical fiber bundle containing approximately 50,000 individual 3.1 microm diameter fibers was chemically etched to create microwells in which cytokine-capture microspheres could be deposited. Microspheres were randomly distributed in the wells to produce an antibody array for performing a multiplexed sandwich immunoassay. The array responded specifically to recombinant cytokine solutions in a concentration-dependent fashion. The array was also used to examine endogenous mediator patterns in saliva supernatants from patients with pulmonary inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD). This array technology may prove useful as a laboratory-based platform for inflammatory disease research and diagnostics, and its small footprint could also enable integration into a microfluidic cassette for use in point-of-care testing.

Array-CGH Analysis in a Cohort of Phenotypically Well-Characterized Individuals with "Essential" Autism Spectrum Disorders

Science.gov (United States)

Napoli, Eleonora; Russo, Serena; Casula, Laura; Alesi, Viola; Amendola, Filomena Alessandra; Angioni, Adriano; Novelli, Antonio; Valeri, Giovanni; Menghini, Deny; Vicari, Stefano

2018-01-01

Copy-number variants (CNVs) are associated with susceptibility to autism spectrum disorder (ASD). To detect the presence of CNVs, we conducted an array-comparative genomic hybridization (array-CGH) analysis in 133 children with "essential" ASD phenotype. Genetic analyses documented that 12 children had causative CNVs (C-CNVs), 29…

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].

Evaluation of Influenza-Specific Humoral Response by Microbead Array Analysis

Directory of Open Access Journals (Sweden)

Yoav Keynan

2011-01-01

Full Text Available RATIONALE: Quantitation and determination of antigen specificity of systemic and mucosal immune responses to influenza vaccination is beneficial for future vaccine development. Previous methods to acquire this information were costly, time consuming and sample exhaustive. The benefits of suspension microbead array (MBA analysis are numerous. The multiplex capabilities of the system conserve time, money and sample, while generating statistically powerful data.

Cyclotron-Resonance-Maser Arrays

International Nuclear Information System (INIS)

Kesar, A.; Lei, L.; Dikhtyar, V.; Korol, M.; Jerby, E.

1999-01-01

The cyclotron-resonance-maser (CRM) array [1] is a radiation source which consists of CRM elements coupled together under a common magnetic field. Each CRM-element employs a low-energy electron-beam which performs a cyclotron interaction with the local electromagnetic wave. These waves can be coupled together among the CRM elements, hence the interaction is coherently synchronized in the entire array. The implementation of the CRM-array approach may alleviate several technological difficulties which impede the development of single-beam gyro-devices. Furthermore, it proposes new features, such as the phased-array antenna incorporated in the CRM-array itself. The CRM-array studies may lead to the development of compact, high-power radiation sources operating at low-voltages. This paper introduces new conceptual schemes of CRM-arrays, and presents the progress in related theoretical and experimental studies in our laboratory. These include a multi-mode analysis of a CRM-array, and a first operation of this device with five carbon-fiber cathodes

Degree-of-Freedom Strengthened Cascade Array for DOD-DOA Estimation in MIMO Array Systems.

Science.gov (United States)

Yao, Bobin; Dong, Zhi; Zhang, Weile; Wang, Wei; Wu, Qisheng

2018-05-14

In spatial spectrum estimation, difference co-array can provide extra degrees-of-freedom (DOFs) for promoting parameter identifiability and parameter estimation accuracy. For the sake of acquiring as more DOFs as possible with a given number of physical sensors, we herein design a novel sensor array geometry named cascade array. This structure is generated by systematically connecting a uniform linear array (ULA) and a non-uniform linear array, and can provide more DOFs than some exist array structures but less than the upper-bound indicated by minimum redundant array (MRA). We further apply this cascade array into multiple input multiple output (MIMO) array systems, and propose a novel joint direction of departure (DOD) and direction of arrival (DOA) estimation algorithm, which is based on a reduced-dimensional weighted subspace fitting technique. The algorithm is angle auto-paired and computationally efficient. Theoretical analysis and numerical simulations prove the advantages and effectiveness of the proposed array structure and the related algorithm.

Enthalpies of dilution of aqueous Li{sub 2}B{sub 4}O{sub 7} solutions at 298.15K and application of ion-interaction model

Energy Technology Data Exchange (ETDEWEB)

Yin Guoyin [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Yao Yan [Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008 (China) and Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: yaoy@isl.ac.cn; Jiao Baojuan [Department of Chemistry, Northwest University, Xi' an 710069 (China); Chen Sanping [Department of Chemistry, Northwest University, Xi' an 710069 (China); Gao Shengli [Department of Chemistry, Northwest University, Xi' an 710069 (China)

2005-09-15

The enthalpies of dilution have been measured for aqueous Li{sub 2}B{sub 4}O{sub 7} solutions from 0.0212 to 2.1530molkg{sup -1} at 298.15K. The relative apparent molar enthalpies, L{sub {phi}}, and relative partial molar enthalpies of the solvent and solute, L-bar{sub 1} and L-bar{sub 2} were calculated. The thermodynamic properties of the complex aqueous solutions were represented with a modified Pitzer ion-interaction model.

Stochastic resolution analysis of co-prime arrays in radar

NARCIS (Netherlands)

Pribic, R; Coutiño Minguez, M.A.; Leus, G.J.T.

2016-01-01

Resolution from co-prime arrays and from a full ULA of the size equal to the virtual size of co-prime arrays is investigated. We take into account not only the resulting beam width but also the fact that fewer measurements are acquired by co-prime arrays. This fact is relevant in compressive

The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, vapor pressure measurements, and ab initio calculations.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas

2007-04-04

Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of vapor pressure, enthalpy of vaporization, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of vaporization of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the vapor pressure measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.

Making sense of enthalpy of vaporization trends for ionic liquids: new experimental and simulation data show a simple linear relationship and help reconcile previous data.

Science.gov (United States)

Verevkin, Sergey P; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Yermalayeu, Andrei V; Schick, Christoph; Liu, Hongjun; Maginn, Edward J; Bulut, Safak; Krossing, Ingo; Kalb, Roland

2013-05-30

Vaporization enthalpy of an ionic liquid (IL) is a key physical property for applications of ILs as thermofluids and also is useful in developing liquid state theories and validating intermolecular potential functions used in molecular modeling of these liquids. Compilation of the data for a homologous series of 1-alkyl-3-methylimidazolium bis(trifluoromethane-sulfonyl)imide ([C(n)mim][NTf2]) ILs has revealed an embarrassing disarray of literature results. New experimental data, based on the concurring results from quartz crystal microbalance, thermogravimetric analyses, and molecular dynamics simulation have revealed a clear linear dependence of IL vaporization enthalpies on the chain length of the alkyl group on the cation. Ambiguity of the procedure for extrapolation of vaporization enthalpies to the reference temperature 298 K was found to be a major source of the discrepancies among previous data sets. Two simple methods for temperature adjustment of vaporization enthalpies have been suggested. Resulting vaporization enthalpies obey group additivity, although the values of the additivity parameters for ILs are different from those for molecular compounds.

Low-temperature heat capacities and standard molar enthalpy of formation of N-methylnorephedrine C211H17NO(s)

Institute of Scientific and Technical Information of China (English)

Di You-Ying; Wang Da-Qi; Shi Quan; Tan Zhi-Cheng

2008-01-01

This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO(s) have been mea- sured by a precision automated adiabatic calorimeter over the temperature range from T=78 K to T=400 K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T=342- 364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T=78-342 K and T=364-400 K were fitted to two poly- nomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO(s) relative to the standard refer- ence temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T=298.15 K was measured by means of an isoperibol preci- sion oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.

Analysis of oligonucleotide array experiments with repeated measures using mixed models

Directory of Open Access Journals (Sweden)

Getchell Thomas V

2004-12-01

Full Text Available Abstract Background Two or more factor mixed factorial experiments are becoming increasingly common in microarray data analysis. In this case study, the two factors are presence (Patients with Alzheimer's disease or absence (Control of the disease, and brain regions including olfactory bulb (OB or cerebellum (CER. In the design considered in this manuscript, OB and CER are repeated measurements from the same subject and, hence, are correlated. It is critical to identify sources of variability in the analysis of oligonucleotide array experiments with repeated measures and correlations among data points have to be considered. In addition, multiple testing problems are more complicated in experiments with multi-level treatments or treatment combinations. Results In this study we adopted a linear mixed model to analyze oligonucleotide array experiments with repeated measures. We first construct a generalized F test to select differentially expressed genes. The Benjamini and Hochberg (BH procedure of controlling false discovery rate (FDR at 5% was applied to the P values of the generalized F test. For those genes with significant generalized F test, we then categorize them based on whether the interaction terms were significant or not at the α-level (αnew = 0.0033 determined by the FDR procedure. Since simple effects may be examined for the genes with significant interaction effect, we adopt the protected Fisher's least significant difference test (LSD procedure at the level of αnew to control the family-wise error rate (FWER for each gene examined. Conclusions A linear mixed model is appropriate for analysis of oligonucleotide array experiments with repeated measures. We constructed a generalized F test to select differentially expressed genes, and then applied a specific sequence of tests to identify factorial effects. This sequence of tests applied was designed to control for gene based FWER.

Vapor pressures and standard molar enthalpies, entropies and Gibbs energies of sublimation of two hexachloro herbicides using a TG unit

International Nuclear Information System (INIS)

Vecchio, Stefano

2010-01-01

The vapor pressures above the solid hexachlorobenzene (HCB) and above both the solid and liquid 1,2,3,4,5,6-hexachlorocyclohexane (lindane) were determined in the ranges 332-450 K and 347-429 K, respectively, by measuring the mass loss rates recorded by thermogravimetry under both isothermal and nonisothermal conditions. The results obtained were compared with those taken from literature. From the temperature dependence of vapor pressure derived by the experimental thermogravimetry data the molar enthalpies of sublimation Δ cr g H m o ( ) were selected for HCB and lindane as well as the molar enthalpy of vaporization Δ l g H m o ( ) for lindane only, at the middle of the respective temperature intervals. The melting temperatures and the molar enthalpies of fusion Δ cr l H m o (T fus ) of lindane were measured by differential scanning calorimetry. Finally, the standard molar enthalpies of sublimation Δ cr g H m o (298.15 K) were obtained for both chlorinated compounds at the reference temperature of 298.15 K using the Δ cr g H m o ( ), Δ l g H m o ( ) and Δ cr l H m o (T fus ) values, as well as the heat capacity differences between gas and liquid and the heat capacity differences between gas and solid, Δ l g C p,m o and Δ cr g C p,m o , respectively, both estimated by applying a group additivity procedure. Therefore, the averages of the standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs energies of sublimation at 298.15 K, have been derived.

Study of the distributions of flow rate and enthalpy in the sub-channels of a bundle geometry of nuclear reactors in one and two-phase flow

International Nuclear Information System (INIS)

Bayoumi, M.A.A.

1976-10-01

A bibliographic study shows that the experimental studies examined, have been developed to understand the phenomenon acting on the mixing between the sub-channels of which geometries are such these of rod bundles used in some nuclear reactors. Experimental devices and tests have been developed to study the influence of the following parameters, operating conditions, pressure, flow rate, power brought to the bundle and inlet temperature on the distribution of flow rates and vapor content among the different sub-channels. By means of non isokinetic sampling, one has determined the enthalpy of the fluid participating to the mixing between the communicating sub-channels and it has been shown that the value of this enthalpy depends strongly on the type of fluid flow and that this enthalpy cannot be either the enthalpy of one of the two sub-channels, nor (always) an average of these two enthalpies. The experimental results have been compared with calculations developed with the code FLICA, concerning the mass velocity distribution, the exchange term of linear momentum, and the variation of the transversal enthalpy with regard to the type of fluid flow. A study of local void ratio measurement, by means of optical probes, has been proposed. The present study has been carried out with a smooth geometry [fr

Romanian earthquakes analysis using BURAR seismic array

International Nuclear Information System (INIS)

Borleanu, Felix; Rogozea, Maria; Nica, Daniela; Popescu, Emilia; Popa, Mihaela; Radulian, Mircea

2008-01-01

Bucovina seismic array (BURAR) is a medium-aperture array, installed in 2002 in the northern part of Romania (47.61480 N latitude, 25.21680 E longitude, 1150 m altitude), as a result of the cooperation between Air Force Technical Applications Center, USA and National Institute for Earth Physics, Romania. The array consists of ten elements, located in boreholes and distributed over a 5 x 5 km 2 area; nine with short-period vertical sensors and one with a broadband three-component sensor. Since the new station has been operating the earthquake survey of Romania's territory has been significantly improved. Data recorded by BURAR during 01.01.2005 - 12.31.2005 time interval are first processed and analyzed, in order to establish the array detection capability of the local earthquakes, occurred in different Romanian seismic zones. Subsequently a spectral ratios technique was applied in order to determine the calibration relationships for magnitude, using only the information gathered by BURAR station. The spectral ratios are computed relatively to a reference event, considered as representative for each seismic zone. This method has the advantage to eliminate the path effects. The new calibration procedure is tested for the case of Vrancea intermediate-depth earthquakes and proved to be very efficient in constraining the size of these earthquakes. (authors)

Recovery and evolutionary analysis of complete integron gene cassette arrays from Vibrio

Directory of Open Access Journals (Sweden)

Gillings Michael R

2006-01-01

Full Text Available Abstract Background Integrons are genetic elements capable of the acquisition, rearrangement and expression of genes contained in gene cassettes. Gene cassettes generally consist of a promoterless gene associated with a recombination site known as a 59-base element (59-be. Multiple insertion events can lead to the assembly of large integron-associated cassette arrays. The most striking examples are found in Vibrio, where such cassette arrays are widespread and can range from 30 kb to 150 kb. Besides those found in completely sequenced genomes, no such array has yet been recovered in its entirety. We describe an approach to systematically isolate, sequence and annotate large integron gene cassette arrays from bacterial strains. Results The complete Vibrio sp. DAT722 integron cassette array was determined through the streamlined approach described here. To place it in an evolutionary context, we compare the DAT722 array to known vibrio arrays and performed phylogenetic analyses for all of its components (integrase, 59-be sites, gene cassette encoded genes. It differs extensively in terms of genomic context as well as gene cassette content and organization. The phylogenetic tree of the 59-be sites collectively found in the Vibrio gene cassette pool suggests frequent transfer of cassettes within and between Vibrio species, with slower transfer rates between more phylogenetically distant relatives. We also identify multiple cases where non-integron chromosomal genes seem to have been assembled into gene cassettes and others where cassettes have been inserted into chromosomal locations outside integrons. Conclusion Our systematic approach greatly facilitates the isolation and annotation of large integrons gene cassette arrays. Comparative analysis of the Vibrio sp. DAT722 integron obtained through this approach to those found in other vibrios confirms the role of this genetic element in promoting lateral gene transfer and suggests a high rate of gene

Enthalpy increment measurements of NaCrO2 using a high temperature Calvet calorimeter

International Nuclear Information System (INIS)

Iyer, V.S.; Jayanthi, K.; Ramarao, G.A.; Venugopal, V.; Sood, D.D.

1991-01-01

Enthalpy increment measurements on NaCrO 2 (s) were carried out in the temperature range 323 to 839 K using a high temperature Calvet micro calorimeter. The enthalpy increment values were least-squares fitted with temperature with the constraint that (Hdeg T - Hdeg 298 ) at 298.18 K equals zero, and can be given by: (Hdeg T - Hdeg 298 ) J/mol) ± 336 = -23515 + 75.364T(K) + 0.01256T 2 (K) (323 to 839 K). The first differential of the above equation with temperature gives the constant pressure molar heat capacity of NaCrO 2 (s), which is given by: Cdeg p (NaCrO 2 , s, T) (J/K mol) = 75.364 + 0.02512T(K). The thermal properties of NaCrO 2 (s) were calculated using the molar heat capacities from the present study and Sdeg(298 K) from the literature. (orig.)

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

below -20 °C in the winter which make liquid-cooled fuel cells impossible. In such cases, air-cooled fuel cell systems are deployed where the air that is fed to the fuel cell serves both as reactant supplier and coolant to remove the waste heat that is generated during fuel cell operation. In some cases...... in order to optimize the operating conditions and the performance of such a system. The adjustable parameters include the fan speed that determines the amount of air that is brought into the system, and the size and rotating speed of the rotating enthalpy wheel. In addition, computational fluid dynamics...... or an ordinary heat exchanger can fulfill the heat recovery demand. Despite the fact that the air enters the stack at a cold temperature, even the forefront of the stack is at a much elevated and desired stack temperature with the help of supplying an acceptable amount of power to an electric stack heater. So...

Vertical nanowire arrays as a versatile platform for protein detection and analysis

DEFF Research Database (Denmark)

Rostgaard, Katrine R.; Frederiksen, Rune S.; Liu, Yi-Chi

2013-01-01

solutions. Here we show that vertical arrays of nanowires (NWs) can overcome several bottlenecks of using nanoarrays for extraction and analysis of proteins. The high aspect ratio of the NWs results in a large surface area available for protein immobilization and renders passivation of the surface between...

Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Liu Min, E-mail: panpanliumin@163.co [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Zhu Lanying [College of Life Science and Bioengineering, Liao Cheng University, Liaocheng, Shandong 252059 (China); Di Youying [College of Chemistry and Chemical Engineering, Liao Cheng University, Liaocheng, Shandong 252059 (China)

2011-06-15

Highlights: Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. The homogeneous enthalpic interaction coefficients were calculated. Apparent molar volumes of the ternary systems were calculated from the data of densities. Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine ({Delta}{sub dil}H{sub m}) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h{sub 2}, h{sub 3}, and h{sub 4}) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h{sub 2}) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density ({rho}) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V{sub {phi}}) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V{sub {phi}}{sup o}) and limiting partial molar volumes of transfer ({Delta}{sub trs}V{sub {phi}}{sup o}) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

Enthalpy of dilution and volumetric properties of N-glycylglycine in aqueous xylitol solutions at T = 298.15 K

International Nuclear Information System (INIS)

Liu Min; Wang Lili; Li Guangqian; Dong Lina; Sun Dezhi; Zhu Lanying; Di Youying

2011-01-01

Highlights: → Enthalpies of dilution of N-glycylglycine in aqueous xylitol solutions were determined at 298.15 K. → The homogeneous enthalpic interaction coefficients were calculated. → Apparent molar volumes of the ternary systems were calculated from the data of densities. → Limiting partial molar volumes and limiting partial molar volumes of transfer were deduced. - Abstract: The enthalpy of dilution of N-glycylglycine (Δ dil H m ) in aqueous xylitol solutions has been determined by means of flow-mix isothermal microcalorimetry at the temperature of 298.15 K. The homogeneous enthalpic interaction coefficients (h 2 , h 3 , and h 4 ) which characterize the interactions of examined N-glycylglycine in aqueous xylitol solutions have been calculated according to the excess enthalpy concept based on the values of dilution enthalpy. It has been found that the enthalpic pair interaction coefficients (h 2 ) in the systems investigated are negative and become less negative as the molality of xylitol increases. Values of the density (ρ) of the ternary homogeneous systems were also measured with a quartz vibrating-tube densimeter at the temperature of 298.15 K. The values of the apparent molar volume (V φ ) of the ternary systems were calculated from the data of density, which have been used to deduce limiting partial molar volumes of N-glycylglycine (V φ o ) and limiting partial molar volumes of transfer (Δ trs V φ o ) from water to aqueous xylitol solutions at different concentrations. The results have been discussed based on solute-solute interactions and solvation effects.

Low-temperature heat capacity and standard molar enthalpy of formation of 9-fluorenemethanol (C14H12O)

International Nuclear Information System (INIS)

Di, You-Ying; Tan, Zhi-Cheng.; Sun, Xiao-Hong; Wang, Mei-Han; Xu, Fen; Liu, Yuan-Fa; Sun, Li-Xian; Zhang, Hong-Tao

2004-01-01

Low-temperature heat capacities of the 9-fluorenemethanol (C 14 H 12 O) have been precisely measured with a small sample automatic adiabatic calorimeter over the temperature range between T=78 K and T=390 K. The solid-liquid phase transition of the compound has been observed to be T fus =(376.567±0.012) K from the heat-capacity measurements. The molar enthalpy and entropy of the melting of the substance were determined to be Δ fus H m =(26.273±0.013) kJ · mol -1 and Δ fus S m =(69.770±0.035) J · K -1 · mol -1 . The experimental values of molar heat capacities in solid and liquid regions have been fitted to two polynomial equations by the least squares method. The constant-volume energy and standard molar enthalpy of combustion of the compound have been determined, Δ c U(C 14 H 12 O, s)=-(7125.56 ± 4.62) kJ · mol -1 and Δ c H m compfn (C 14 H 12 O, s)=-(7131.76 ± 4.62) kJ · mol -1 , by means of a homemade precision oxygen-bomb combustion calorimeter at T=(298.15±0.001) K. The standard molar enthalpy of formation of the compound has been derived, Δ f H m compfn (C 14 H 12 O,s)=-(92.36 ± 0.97) kJ · mol -1 , from the standard molar enthalpy of combustion of the compound in combination with other auxiliary thermodynamic quantities through a Hess thermochemical cycle

Resorcinol adsorption from aqueous solution on activated carbon: Relation adsorption isotherm and immersion enthalpy

International Nuclear Information System (INIS)

Blanco, Diago A; Giraldo, Liliana; Moreno, Juan C.

2008-01-01

The resorcinol adsorption on a modified activated carbon, obtained from an activated commercial carbon Carbochem T M - PS30, CAG, modified by means of chemical treatment with HNO 3 7M oxidized activated carbon (CAO) and heat treatment under H 2 flow, reduced activated carbon (CAR) are studied. The influence of solution pH, the reduction and oxidation of the activated surface carbons in resorcinol aqueous solutions is determined. The interaction solid solution is characterized by adsorption isotherms analysis at 298 K and at pHs of 7.9 and 11 in order to evaluate the system on and below the value of resorcinol pKa. The adsorption capacity of carbons increases with diminishing solution pH. The amount retained increases in the reduced carbon at maximum adsorption pH and diminishes in the oxidized carbon. the experimental results of the adsorption isotherms are adjusted to the Freundlich and Langmuir models, obtaining values for the Q m ax parameter Langmuir model in the CAG of 179, 156 and 44 mgg - 1 For pH values of 7,9 and 11 respectively. In this case of modified carbons values of 233, 179 and 164 mgg - 1 Are obtained for CAR, CAG and CAO to pH 7 respectively, as general tendency the resorcinol adsorption increases in the following order CAR > CAG > CAO. Similar conclusions from immersion enthalpies are obtained, their values increase with the amount of solute retained. In the case of the CAG, immersion enthalpies between 25.8 to 40.9 Jg - 1, are obtained for resorcinol aqueous solutions in a range from 20 to 1500 mgL - 1

Ca(AlH4)2, CaAlH5, and CaH2+6LiBH4: Calculated dehydrogenation enthalpy, including zero point energy, and the structure of the phonon spectra.

Science.gov (United States)

Marashdeh, Ali; Frankcombe, Terry J

2008-06-21

The dehydrogenation enthalpies of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) have been calculated using density functional theory calculations at the generalized gradient approximation level. Harmonic phonon zero point energy (ZPE) corrections have been included using Parlinski's direct method. The dehydrogenation of Ca(AlH(4))(2) is exothermic, indicating a metastable hydride. Calculations for CaAlH(5) including ZPE effects indicate that it is not stable enough for a hydrogen storage system operating near ambient conditions. The destabilized combination of LiBH(4) with CaH(2) is a promising system after ZPE-corrected enthalpy calculations. The calculations confirm that including ZPE effects in the harmonic approximation for the dehydrogenation of Ca(AlH(4))(2), CaAlH(5), and CaH(2)+6LiBH(4) has a significant effect on the calculated reaction enthalpy. The contribution of ZPE to the dehydrogenation enthalpies of Ca(AlH(4))(2) and CaAlH(5) calculated by the direct method phonon analysis was compared to that calculated by the frozen-phonon method. The crystal structure of CaAlH(5) is presented in the more useful standard setting of P2(1)c symmetry and the phonon density of states of CaAlH(5), significantly different to other common complex metal hydrides, is rationalized.

The composition of the saturated vapor and enthalpies of dimerization of rubidium and cesium pivalates

International Nuclear Information System (INIS)

Khoretonenko, N.M.; Rykov, A.N.; Korenev, Yu.M.

1998-01-01

The rubidium and cesium pivalates sublimation processes are studied through the Knudsen effusion method with the mass-spectral analysis of the gaseous phase composition. It is established that MPiv and M 2 Piv 2 and in small amounts M 3 Piv 3 and M 4 Piv 4 constitute the basic components in the saturated vapour of the rubidium and cesium pivalates. Sublimation enthalpies (kJ/mole) of monomers Δ S H T 0 =163.5±7.2 and dimers Δ S H T 0 (Cs 2 Piv 2 )-192.1±9.6 are determined. Dissociation enthalpies (kJ/mole) of the M 2 Piv 2 dimers by the second(2) and the third (3) laws of thermodynamics: Δ D H T 0 (Cs 2 Piv 2 )=137.1±5.4(2), Δ D H T 0 (Rb 2 Piv 2 )=138.2±10.2 (3); Δ D H T 0 (Cs 2 Piv 2 )-134.9±9.3 (2), Δ D H T 0 (Cs 2 Piv 2 )=136.8±10.8 (3) are calculated. Temperature dependence equations (210-300 deg C of partial pressures (Pa) of the MPiv, M 2 Piv 2 molecules: InP(RbPiv)=-(20099±674)/T+34.6±1.2; InP(Rb 2 Piv 2 )=-(23707±734)/T+40.4±1.4; InP(CsPiv)=-(19666±866)/T+34.1±1.6; InP(Cs 2 Piv 2 )=-(23106±1155)/T+39.5±2.1 are obtained

OpenMSI Arrayed Analysis Toolkit: Analyzing Spatially Defined Samples Using Mass Spectrometry Imaging

Energy Technology Data Exchange (ETDEWEB)

de Raad, Markus [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); de Rond, Tristan [Univ. of California, Berkeley, CA (United States); Rübel, Oliver [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Keasling, Jay D. [Univ. of California, Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Technical Univ. of Denmark, Lyngby (Denmark); Northen, Trent R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Bowen, Benjamin P. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)

2017-05-03

Mass spectrometry imaging (MSI) has primarily been applied in localizing biomolecules within biological matrices. Although well-suited, the application of MSI for comparing thousands of spatially defined spotted samples has been limited. One reason for this is a lack of suitable and accessible data processing tools for the analysis of large arrayed MSI sample sets. In this paper, the OpenMSI Arrayed Analysis Toolkit (OMAAT) is a software package that addresses the challenges of analyzing spatially defined samples in MSI data sets. OMAAT is written in Python and is integrated with OpenMSI (http://openmsi.nersc.gov), a platform for storing, sharing, and analyzing MSI data. By using a web-based python notebook (Jupyter), OMAAT is accessible to anyone without programming experience yet allows experienced users to leverage all features. OMAAT was evaluated by analyzing an MSI data set of a high-throughput glycoside hydrolase activity screen comprising 384 samples arrayed onto a NIMS surface at a 450 μm spacing, decreasing analysis time >100-fold while maintaining robust spot-finding. The utility of OMAAT was demonstrated for screening metabolic activities of different sized soil particles, including hydrolysis of sugars, revealing a pattern of size dependent activities. Finally, these results introduce OMAAT as an effective toolkit for analyzing spatially defined samples in MSI. OMAAT runs on all major operating systems, and the source code can be obtained from the following GitHub repository: https://github.com/biorack/omaat.

A compilation of correlation parameters for predicting the enthalpy and thermal conductivity of solid foods within the temperature range of -40 C to +40 C

Energy Technology Data Exchange (ETDEWEB)

Amos, N.D. [Comvita New Zealand Limited, Private Bag 1, Te Puke 3153 (New Zealand); Willix, J.; North, M.F. [AgResearch Limited, MIRINZ Centre, Ruakura Campus, East Street, Private Bag 3123, Hamilton (New Zealand); Chadderton, T. [Crop and Food Research Ltd, PO Box 5114, Nelson (New Zealand)

2008-11-15

This paper presents thermal conductivity data for 40 foods, enthalpy data for 58 foods and density data for nine foods, along with the compositions of the foods. Measurements cover a range of solid food types (including meats, fats, offal, fish, dairy products and horticultural products). Some measurements reported are for foods that have never before been studied, others have been published elsewhere, but are included here for convenience. Thermal conductivity was measured using a guarded hot-plate apparatus, enthalpy using an adiabatic calorimeter and density using a water displacement meter. Thermal conductivity and enthalpy values were measured within the temperature range of -40 C to +40 C. (author) [French] Cette publication presente des donnes sur la conductivite thermique, l'enthalpie et la densite respectivement de 40, 58 et 9 produits alimentaires, ainsi que leurs compositions. Les mesures couvrent une variete de types de produits alimentaires (viande, matieres grasses, abats, poisson, produits laitiers, produits horticoles). Certaines sont rapportees pour des produits qui n 'ant jamais ete etudie auparavant, d'autres ant ete publie ailleurs mais sont aussi inclues pour plus de commodite. La conductivite thermique a ete mesure avec un appareil a plaque electrique protegee, l'enthalpie avec un calorimetre adiabatique et la densite avec un appareil mesurant Ie deplacement d'eau. La conductivite thermique et l'enthalpie ont ete toutes les mesures pour une fourchette de temperatures allant de -40 C a 40 C. (orig.)

Enthalpies of formation of Cd0.917Sr0.083, Cd0.857Sr0.143 and Cd0.667Sr0.333 intermetallic compounds

International Nuclear Information System (INIS)

Agarwal, Renu; Singh, Ziley

2008-01-01

Cadmium is expected to be the solvent for pyrochemical processing of the metallic nuclear fuel. Therefore, thermodynamic properties of cadmium with various fuel and clad elements are of interest. Enthalpies of formation of the intermetallic compounds of Cd-Sr system, Cd 0.917 Sr 0.083 , Cd 0.857 Sr 0.143 and Cd 0.667 Sr 0.333 were determined by precipitation using Calvet calorimeter. Enthalpies of formation of the compounds were found to be -3.05 ± 0.5 kJ mol -1 at 723 K, -14.2 ± 0.7 kJ mol -1 at 843 K and -28.4 ± 0.8 kJ mol -1 at 863 K, respectively. Enthalpies of formation of Cd 0.917 Sr 0.083 and Cd 0.857 Sr 0.143 were also determined by partial enthalpy of formation measurements and the values were found to be -3.9 ± 1.1 kJ mol -1 at 723 K and -13.42 ± 1.2 kJ mol -1 at 843 K, respectively. Miedema model was used to estimate the enthalpies of formation of these compounds and the estimated values were compared with the experimentally determined values

TiArA: a virtual appliance for the analysis of Tiling Array data.

Directory of Open Access Journals (Sweden)

Jason A Greenbaum

2010-04-01

Full Text Available Genomic tiling arrays have been described in the scientific literature since 2003, yet there is a shortage of user-friendly applications available for their analysis.Tiling Array Analyzer (TiArA is a software program that provides a user-friendly graphical interface for the background subtraction, normalization, and summarization of data acquired through the Affymetrix tiling array platform. The background signal is empirically measured using a group of nonspecific probes with varying levels of GC content and normalization is performed to enforce a common dynamic range.TiArA is implemented as a standalone program for Linux systems and is available as a cross-platform virtual machine that will run under most modern operating systems using virtualization software such as Sun VirtualBox or VMware. The software is available as a Debian package or a virtual appliance at http://purl.org/NET/tiara.

Single-electron tunnel junction array

International Nuclear Information System (INIS)

Likharev, K.K.; Bakhvalov, N.S.; Kazacha, G.S.; Serdyukova, S.I.

1989-01-01

The authors have carried out an analysis of statics and dynamics of uniform one-dimensional arrays of ultrasmall tunnel junctions. The correlated single-electron tunneling in the junctions of the array results in its behavior qualitatively similar to that of the Josephson transmission line. In particular, external electric fields applied to the array edges can inject single-electron-charged solitons into the array interior. Shape of such soliton and character of its interactions with other solitons and the array edges are very similar to those of the Josephson vortices (sine-Gordon solitons) in the Josephson transmission line. Under certain conditions, a coherent motion of the soliton train along the array is possible, resulting in generation of narrowband SET oscillations with frequency f/sub s/ = /e where is the dc current flowing along the array

The thermodynamic properties of the upper continental crust: Exergy, Gibbs free energy and enthalpy

International Nuclear Information System (INIS)

Valero, Alicia; Valero, Antonio; Vieillard, Philippe

2012-01-01

This paper shows a comprehensive database of the thermodynamic properties of the most abundant minerals of the upper continental crust. For those substances whose thermodynamic properties are not listed in the literature, their enthalpy and Gibbs free energy are calculated with 11 different estimation methods described in this study, with associated errors of up to 10% with respect to values published in the literature. Thanks to this procedure we have been able to make a first estimation of the enthalpy, Gibbs free energy and exergy of the bulk upper continental crust and of each of the nearly 300 most abundant minerals contained in it. Finally, the chemical exergy of the continental crust is compared to the exergy of the concentrated mineral resources. The numbers obtained indicate the huge chemical exergy wealth of the crust: 6 × 10 6 Gtoe. However, this study shows that approximately only 0.01% of that amount can be effectively used by man.

Enthalpy of mixing and heat of vaporization of ethyl acetate with benzene and toluene at 298.15 k and 308.15 k

Directory of Open Access Journals (Sweden)

K. L. Shivabasappa

2008-03-01

Full Text Available The present work was carried out in two phases. First, enthalpy of mixing was measured and then the heat of vaporization for the same mixtures was obtained. The data are useful in the design of separation equipments. From the various designs available for the experimental determination of enthalpy of mixing, and heat of vaporization, the apparatus was selected, modified and constructed. The apparatus of enthalpy of mixing was tested with a known system Benzene - i-Butyl Alcohol and the data obtained was in very good agreement with literature values. Experiments were then conducted for mixtures of Ethyl Acetate with Benzene and Toluene. The experimental data was fitted to the standard correlations and the constants were evaluated. Heat of vaporization data were obtained from a static apparatus and tested for accuracy by conducting experiments with a known system Benzene - n-Hexane and the data obtained were found to be in agreement with literature values. Experiments were then conducted to measure heat of vaporization for the mixtures of Ethyl Acetate with Benzene and Toluene. Using experimental data of enthalpy of mixing from the first phase, and heat capacity data, the heat of vaporization were calculated.

Vapour pressures and enthalpies of vaporization of a series of the linear n-alkyl acetates

Czech Academy of Sciences Publication Activity Database

Krasnykh, E. L.; Verevkin, S. P.; Koutek, Bohumír; Doubský, Jan

2006-01-01

Roč. 38, č. 6 (2006), s. 717-723 ISSN 0021-9614 Institutional research plan: CEZ:AV0Z40550506 Keywords : aliphatic acetates * transpiration method * vapour pressure * enthalpy of vaporization Subject RIV: CC - Organic Chemistry Impact factor: 1.842, year: 2006

Liquid-Liquid Equilibrium and Excess Enthalpies in the Binary System 2-Methylpentane + N,N-Dimethylformamide

Czech Academy of Sciences Publication Activity Database

Bendová, Magdalena; Řehák, K.; Matouš, J.; Novák, J. P.

2004-01-01

Roč. 49, č. 5 (2004), s. 1318-1322 ISSN 0021-9568 Institutional research plan: CEZ:AV0Z4072921 Keywords : liquid-liquid equilibrium * excess enthalpies * thermodynamic models Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.368, year: 2004

Flat-plate photovoltaic array design optimization

Science.gov (United States)

Ross, R. G., Jr.

1980-01-01

An analysis is presented which integrates the results of specific studies in the areas of photovoltaic structural design optimization, optimization of array series/parallel circuit design, thermal design optimization, and optimization of environmental protection features. The analysis is based on minimizing the total photovoltaic system life-cycle energy cost including repair and replacement of failed cells and modules. This approach is shown to be a useful technique for array optimization, particularly when time-dependent parameters such as array degradation and maintenance are involved.

Method of determining the enthalpy and moisture content of wet steam

International Nuclear Information System (INIS)

Silvestri, G.J. Jr.

1991-01-01

This patent describes a nuclear powered multi-stage steam turbine system wherein steam at higher than atmospheric pressure is introduced into the turbine system at a high pressure turbine element and thereafter flows through a series of turbine elements at successively decreasing pressures, wherein portions of the steam are extracted from the turbine elements at a plurality of lower pressure points and the steam is finally exhausted at a lowest pressure point, the method of determining moisture content and enthalpy of steam at a selected pressure point. It comprises sampling a small quantity of steam at the selected pressure point; super heating the steam sample to a single-phase state by reducing its pressure and bottling it in a closed measuring chamber whereby the flow energy of the sample is converted into internal energy; measuring the pressure of the steam sample within the chamber; determining the sonic velocity of the steam sample by passing a sound wave through the sample from a transmitter to a receiver located at a known distance from the transmitter and measuring the time required for the sound wave to travel from transmitter to receiver; and utilizing the measured pressure and sonic velocity of the steam sample to calculate the moisture content and enthalpy of the steam at the selected pressure point

An Introduction to MAMA (Meta-Analysis of MicroArray data) System.

Science.gov (United States)

Zhang, Zhe; Fenstermacher, David

2005-01-01

Analyzing microarray data across multiple experiments has been proven advantageous. To support this kind of analysis, we are developing a software system called MAMA (Meta-Analysis of MicroArray data). MAMA utilizes a client-server architecture with a relational database on the server-side for the storage of microarray datasets collected from various resources. The client-side is an application running on the end user's computer that allows the user to manipulate microarray data and analytical results locally. MAMA implementation will integrate several analytical methods, including meta-analysis within an open-source framework offering other developers the flexibility to plug in additional statistical algorithms.

Outlook on principles for designing integrated and cascade use of low enthalpy geothermal energy in Albania

International Nuclear Information System (INIS)

Frasheri, Alfred

2000-01-01

In the countries of Western Europe, USA and Japan, the technologies of a new generation evolved to exploit high and low enthalpy geothermal sources and mineral waters. There are great experiences for modern complex exploitation of these resources, which increase natural wealth values, in European Community Countries. In Albania, rich in geothermal resources of low enthalpy and mineral waters, similar new technologies have been either partly developed or remain still untouched. Modern complex exploitation is very rare phenomena. Large numbers of geothermal energy of high and low enthalpy resources, a lot of mineral water sources and some CO 2 gas reservoirs represent the base for successfully application of modern technologies in Albania, to achieve economic effectively and success of complex exploitation. Actuality, there are many geothermal, hydrogeological, hydrochemical, biological and medical investigations and studies of thermal and mineral water resources carried out in Albania. Generally, these investigations and studies are separated each from the other. Their information and data will serve for studies and evaluations in Albania regional scale. These studies and evaluations are necessary to well know in regional plane the thermal and mineral water resources potential and geothermal market of the Albania. According to results of these new studies, the evaluation for the perspective level of the best areas in country will be necessary. After the evaluation is possible to start investments in these areas. These investments will be profitable in a short period of time. Integrated and cascade use of geothermal energy of low enthalpy it is important condition for profitable investment. In Albania, there are several geothermal energy sources that can be used. Such geothermal energy sources are natural thermal water springs and deep wells with a temperature of up to 65,5 o C. Deep abandoned oil wells can be used as 'Vertical Earth Heat Probe'. The integrated and

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.

Using Enthalpy as a Prognostic Variable in Atmospheric Modelling with Variable Composition

Science.gov (United States)

2016-04-14

Sela, personal communication, 2005). These terms are also routinely neglected in models. In models with a limited number of gaseous tracers, such as...so-called energy- exchange term (second term on the left- hand side) in Equation (5). The finite-difference schemes in existing atmospheric models have...equation for the sum of enthalpy and kinetic energy of horizontal motion is solved. This eliminates the energy- exchange term and automatically

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

KAUST Repository

Han, Xiao; Lee, Richmond; Chen, Tao; Luo, Jie; Lu, Yixin; Huang, Kuo-Wei

2013-01-01

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.

Performance analysis of solar cell arrays in concentrating light intensity

International Nuclear Information System (INIS)

Xu Yongfeng; Li Ming; Lin Wenxian; Wang Liuling; Xiang Ming; Zhang Xinghua; Wang Yunfeng; Wei Shengxian

2009-01-01

Performance of concentrating photovoltaic/thermal system is researched by experiment and simulation calculation. The results show that the I-V curve of the GaAs cell array is better than that of crystal silicon solar cell arrays and the exergy produced by 9.51% electrical efficiency of the GaAs solar cell array can reach 68.93% of the photovoltaic/thermal system. So improving the efficiency of solar cell arrays can introduce more exergy and the system value can be upgraded. At the same time, affecting factors of solar cell arrays such as series resistance, temperature and solar irradiance also have been analyzed. The output performance of a solar cell array with lower series resistance is better and the working temperature has a negative impact on the voltage in concentrating light intensity. The output power has a -20 W/V coefficient and so cooling fluid must be used. Both heat energy and electrical power are then obtained with a solar trough concentrating photovoltaic/thermal system. (semiconductor devices)

Accuracy of the DLPNO-CCSD(T) method for non-covalent bond dissociation enthalpies from coinage metal cation complexes

KAUST Repository

Minenkov, Yury; Chermak, Edrisse; Cavallo, Luigi

2015-01-01

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.

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.

Glass transition memorized by the enthalpy-entropy compensation in the shear thinning of supercooled metallic liquids

Science.gov (United States)

Zhang, Meng; Liu, Lin

2018-06-01

To unravel the true nature of glass transition, broader insights into glass forming have been gained by examining the stress-driven glassy systems, where strong shear thinning, i.e. a reduced viscosity under increasing shear rate, is encountered. It is argued that arbitrarily small stress-driven shear rates would ‘melt’ the glass and erase any memory of its thermal history. In this work, we report a glass transition memorized by the enthalpy-entropy compensation in strongly shear-thinned supercooled metallic liquids, which coincides with the thermal glass transition in both the transition temperature and the activation Gibbs free energy. Our findings provide distinctive insights into both glass forming and shear thinning, and enrich current knowledge on the ubiquitous enthalpy-entropy compensation empirical law in condensed matter physics.

Theoretical calculation of enthalpy of formation of multiconformational molecules: 1,2-ethanediol, propanediols, and glycerol

Science.gov (United States)

Dorofeeva, Olga V.; Suchkova, Taisiya A.

2018-04-01

The gas-phase enthalpies of formation of four molecules with high flexibility, which leads to the existence of a large number of low-energy conformers, were calculated with the G4 method to see whether the lowest energy conformer is sufficient to achieve high accuracy in the computed values. The calculated values were in good agreement with the experiment, whereas adding the correction for conformer distribution makes the agreement worse. The reason for this effect is a large anharmonicity of low-frequency torsional motions, which is ignored in the calculation of ZPVE and thermal enthalpy. It was shown that the approximate correction for anharmonicity estimated using a free rotor model is of very similar magnitude compared with the conformer correction but has the opposite sign, and thus almost fully compensates for it. Therefore, the common practice of adding only the conformer correction is not without problems.

Standard partial molar heat capacities and enthalpies of formation of aqueous aluminate under hydrothermal conditions from integral heat of solution measurements

International Nuclear Information System (INIS)

Coulier, Yohann; Tremaine, Peter R.

2014-01-01

Highlights: • Heats of solution of NaAlO 2 (s) were measured at five temperatures up to 250 °C. • Standard molar enthalpies of solution were determined from the measured heats of solution. • Standard molar enthalpies of solution were correlated with the density model. • The density model allows us to determine the standard molar heat capacities of reaction. - Abstract: Heats of solution of sodium aluminum oxide, NaAlO 2 (s), were measured in aqueous sodium hydroxide solutions using a Tian–Calvet heat-flow calorimeter (Setaram, Model C80) with high pressure “batch cells” made of hastelloy C-276, at five temperatures from (373.15 to 523.15) K, steam saturation pressure, and concentrations from (0.02 to 0.09) mol · kg −1 . Standard molar enthalpies of solution, Δ soln H ∘ , and relative standard molar enthalpies, [H ∘ (T) − H ∘ (298.15 K)], of NaAl(OH) 4 (aq) were determined from the measured heats of solution. The results were fitted with the “density” model. The temperature dependence of Δ soln H ∘ from the model yielded the standard molar heat capacities of reaction, Δ soln C p ∘ , from which standard partial molar heat capacities for aqueous aluminate, C p ∘ [A1(OH) 4 − ,aq], were calculated. Standard partial molar enthalpies of formation, Δ f H ∘ , and entropies, S ∘ , of A1(OH) 4 − (aq) were also determined. The values for C p ∘ [A1(OH) 4 − ,aq] agree with literature data determined up to T = 413 K from enthalpy of solution and heat capacity measurements to within the combined experimental uncertainties. They are consistent with differential heat capacity measurements up to T = 573 K from Schrödle et al. (2010) [29] using the same calorimeter, but this method has the advantage that measurements could be made at much lower concentrations in the presence of an excess concentration of ligand. To our knowledge, these are the first standard partial molar heat capacities measured under hydrothermal conditions by the

Air-Sea Momentum and Enthalpy Exchange in Coupled Atmosphere-Wave-Ocean Modeling of Tropical Cyclones

Science.gov (United States)

Curcic, M.; Chen, S. S.

2016-02-01

The atmosphere and ocean are coupled through momentum, enthalpy, and mass fluxes. Accurate representation of these fluxes in a wide range of weather and climate conditions is one of major challenges in prediction models. Their current parameterizations are based on sparse observations in low-to-moderate winds and are not suited for high wind conditions such as tropical cyclones (TCs) and winter storms. In this study, we use the Unified Wave INterface - Coupled Model (UWIN-CM), a high resolution, fully-coupled atmosphere-wave-ocean model, to better understand the role of ocean surface waves in mediating air-sea momentum and enthalpy exchange in TCs. In particular, we focus on the explicit treatment of wave growth and dissipation for calculating atmospheric and oceanic stress, and its role in upper ocean mixing and surface cooling in the wake of the storm. Wind-wave misalignment and local wave disequilibrium result in difference between atmospheric and oceanic stress being largest on the left side of the storm. We find that explicit wave calculation in the coupled model reduces momentum transfer into the ocean by more than 10% on average, resulting in reduced cooling in TC's wake and subsequent weakening of the storm. We also investigate the impacts of sea surface temperature and upper ocean parameterization on air-sea enthalpy fluxes in the fully coupled model. High-resolution UWIN-CM simulations of TCs with various intensities and structure are conducted in this study to better understand the complex TC-ocean interaction and improve the representation of air-sea coupling processes in coupled prediction models.

Development of a subchannel analysis code MATRA (Ver. α)

International Nuclear Information System (INIS)

Yoo, Y. J.; Hwang, D. H.

1998-04-01

A subchannel analysis code MATRA-α, an interim version of MATRA, has been developed to be run on an IBM PC or HP WS based on the existing CDC CYBER mainframe version of COBRA-IV-I. This MATRA code is a thermal-hydraulic analysis code based on the subchannel approach for calculating the enthalpy and flow distribution in fuel assemblies and reactor cores for both steady-state and transient conditions. MATRA-α has been provided with an improved structure, various functions, and models to give the more convenient user environment and to increase the code accuracy, various functions, and models to give the more convenient user environment and to increase the code accuracy. Among them, the pressure drop model has been improved to be applied to non-square-lattice rod arrays, and the lateral transport models between adjacent subchannels have been improved to increase the accuracy in predicting two-phase flow phenomena. Also included in this report are the detailed instructions for input data preparation and for auxiliary pre-processors to serve as a guide to those who want to use MATRA-α. In addition, we compared the predictions of MATRA-α with the experimental data on the flow and enthalpy distribution in three sample rod-bundle cases to evaluate the performance of MATRA-α. All the results revealed that the prediction of MATRA-α were better than those of COBRA-IV-I. (author). 16 refs., 1 tab., 13 figs

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.

Vrancea seismic source analysis using a small-aperture array

International Nuclear Information System (INIS)

Popescu, E.; Popa, M.; Radulian, M.; Placinta, A.O.

2005-01-01

A small-aperture seismic array (BURAR) was installed in 1999 in the northern part of the Romanian territory (Bucovina area). Since then, the array has been in operation under a joint cooperation programme between Romania and USA. The array consists of 10 stations installed in boreholes (nine short period instruments and one broadband instrument) with enough high sensitivity to properly detect earthquakes generated in Vrancea subcrustal domain (at about 250 km epicentral distance) with magnitude M w below 3. Our main purpose is to investigate and calibrate the source parameters of the Vrancea intermediate-depth earthquakes using specific techniques provided by the BURAR array data. Forty earthquakes with magnitudes between 2.9 and 6.0 were selected, including the recent events of September 27, 2004 (45.70 angle N, 26.45 angle E, h = 166 km, M w = 4.7), October 27, 2004 (45.84 angle N, 26.63 angle E, h = 105 km, M w = 6.0) and May 14, 2005 (45.66 angle N, 26.52 angle E, h = 146 km, M w = 5.1), which are the best ever recorded earthquakes on the Romanian territory: Empirical Green's function deconvolution and spectral ratio methods are applied for pairs of collocated events with similar focal mechanism. Stability tests are performed for the retrieved source time function using the array elements. Empirical scaling and calibration relationships are also determined. Our study shows the capability of the BURAR array to determine the source parameters of the Vrancea intermediate-depth earthquakes as a stand alone station and proves that the recordings of this array alone provides reliable and useful tools to efficiently constrain the source parameters and consequently source scaling properties. (authors)

The relation between relaxed enthalpy and volume during physical aging of amorphous polymers and selenium

Czech Academy of Sciences Publication Activity Database

Slobodian, P.; Říha, Pavel; Rychwalski, R. W.; Emri, I.; Sáha, P.; Kubát, J.

2006-01-01

Roč. 42, č. 10 (2006), s. 2824-2837 ISSN 0014-3057 R&D Projects: GA AV ČR IAA2060401 Institutional research plan: CEZ:AV0Z20600510 Keywords : Enthalpy relaxation * Polymer aging Subject RIV: BJ - Thermodynamics Impact factor: 2.113, year: 2006

Applicability of the theory of thermodynamic similarity to predict the enthalpies of vaporization of aliphatic aldehydes

Science.gov (United States)

Esina, Z. N.; Korchuganova, M. R.

2015-06-01

The theory of thermodynamic similarity is used to predict the enthalpies of vaporization of aliphatic aldehydes. The predicted data allow us to calculate the phase diagrams of liquid-vapor equilibrium in a binary water-aliphatic aldehyde system.

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....

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....

Group additivity values for enthalpies of formation (298 K), entropies (298 K), and molar heat capacities (300 K < T < 1500 K) of gaseous fluorocarbons

International Nuclear Information System (INIS)

Van Otterloo, Maren K.; Girshick, Steven L.; Roberts, Jeffrey T.

2007-01-01

A group additivity method was developed to estimate standard enthalpies of formation and standard entropies at 298 K of linear radical and closed-shell, gaseous fluorocarbon neutrals containing four or more carbon atoms. The method can also be used to estimate constant pressure molar heat capacities of the same compounds over the temperature range 300 K to 1500 K. Seventeen groups and seven fluorine-fluorine interaction terms were defined from 12 fluorocarbon molecules. Interaction term values from Yamada and Bozzelli [T. Yamada, J.W. Bozzelli, J. Phys. Chem. A 103 (1999) 7373-7379] were utilized. The enthalpy of formation group values were derived from G3MP2 calculations by Bauschlicher and Ricca [C.W. Bauschlicher, A. Ricca, J. Phys. Chem. A 104 (2000) 4581-4585]. Standard entropy and molar heat capacity group values were estimated from ab initio geometry optimization and frequency calculations at the Hartree-Fock level using the 6-31G(d) basis set. Enthalpies of formation for larger fluorocarbons estimated from the group additivity method compare well to enthalpies of formation found in the literature

Indoor air quality inspection and analysis system based on gas sensor array

Science.gov (United States)

Gao, Xiang; Wang, Mingjiang; Fan, Binwen

2017-08-01

A detection and analysis system capable of measuring the concentration of four major gases in indoor air is designed. It uses four gas sensors constitute a gas sensor array, to achieve four indoor gas concentration detection, while the detection of data for further processing to reduce the cross-sensitivity between the gas sensor to improve the accuracy of detection.

Experimental measurement of enthalpy increments of Th0.25Ce0.75O2

International Nuclear Information System (INIS)

Babu, R.; Balakrishnan, S.; Ananthasivan, K.; Nagarajan, K.

2013-01-01

Thorium has been suggested as an alternative fertile material for a nuclear fuel cycle, and an inert matrix for burning plutonium and for waste disposal. The third stage of India's nuclear power programme envisages utilization of thorium and plutonium as a fuel in Advanced Heavy Water Reactor (AHWR) and Accelerator Driven Sub-critical Systems (ADSS). Solid solutions of ThO 2 -PuO 2 are of importance because of coexistence of Th with Pu during the breeding cycle. CeO 2 is used as a PuO 2 analog due to similar ionic radii of cations and similar physico-chemical properties of the oxides. ThO 2 forms a homogeneous solid solution with the cubic fluorite structure when doped with Ce in the entire compositional range. In the development of mixed oxide nuclear fuels, knowledge of thermodynamic properties of thorium oxide and its mixtures has become extremely importance for understanding the fuel behavior during irradiation and for predicting the performance of the fuel under accidental conditions. Thermodynamic functions such as the enthalpy increment and heat capacity of the theria-ceria solid solution have not been measured experimentally. Hence, the enthalpy increments of thoria-ceria solid solutions, Th 0.25 Ce 0.75 O 2 by inverse drop calorimetry in the temperature range 523-1723 K have been measured. The measured enthalpy increments were fitted in to polynomial functions by using the least squares method and the other thermodynamic functions such as heat capacity, entropy and Gibbs energy functions were computed in the temperature range 298-1800 K. The reported thermodynamic functions for Th 0.25 Ce 0.75 O 2 forms the first experimental data and the heat capacity of (Th,Ce)O 2 solid solutions was shown to obey the Neumann-Kopp's rule. (author)

The OncoArray Consortium

DEFF Research Database (Denmark)

Amos, Christopher I; Dennis, Joe; Wang, Zhaoming

2017-01-01

by Illumina to facilitate efficient genotyping. The consortium developed standard approaches for selecting SNPs for study, for quality control of markers, and for ancestry analysis. The array was genotyped at selected sites and with prespecified replicate samples to permit evaluation of genotyping accuracy...... among centers and by ethnic background. RESULTS: The OncoArray consortium genotyped 447,705 samples. A total of 494,763 SNPs passed quality control steps with a sample success rate of 97% of the samples. Participating sites performed ancestry analysis using a common set of markers and a scoring...

Formation enthalpies of LaLn'O{sub 3} (Ln'=Ho, Er, Tm and Yb) interlanthanide perovskites

Energy Technology Data Exchange (ETDEWEB)

Qi, Jianqi [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Key Laboratory of Radiation Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064 (China); Key Laboratory of High Energy Density Physics of Ministry of Education, Sichuan University, Chengdu 610064 (China); Guo, Xiaofeng [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States); Mielewczyk-Gryn, Aleksandra [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States); Faculty of Applied Physics and Mathematics, Department of Solid State Physics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk (Poland); Navrotsky, Alexandra, E-mail: anavrotsky@ucdavis.edu [Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California, Davis, CA 95616 (United States)

2015-07-15

High-temperature oxide melt solution calorimetry using 3Na{sub 2}O·MoO{sub 3} at 802 °C was performed for interlanthanide perovskites LaLn'O{sub 3} (Ln'=Ho, Er, Tm and Yb) and lanthanide oxides (La{sub 2}O{sub 3}, Ho{sub 2}O{sub 3}, Er{sub 2}O{sub 3}, Tm{sub 2}O{sub 3} and Yb{sub 2}O{sub 3}). The enthalpies of formation of these interlanthanide perovskites from binary lanthanide oxides at room temperature (25 °C) were determined to be −8.3±3.4 kJ/mol for LaHoO{sub 3}, −9.9±3.0 kJ/mol for LaErO{sub 3}, −10.8±2.7 kJ/mol for LaTmO{sub 3} and −12.3±2.9 kJ/mol for LaYbO{sub 3}. There is a roughly linear relationships between these enthalpy values and the tolerance factor for these and for other LaM{sup 3+}O{sub 3} (M=In, Sc, Ga, Al, Fe and Cr) perovskites, confirming that the distortion of the perovskites as results from ionic radius difference of A-site and B-site cations, is the main factor determining the stability of these compounds. - Graphical abstract: A linear relationship between the enthalpy of formation and the tolerance factor for interlanthanide LaLn'O{sub 3} (Ln'=Ho, Er, Tm, and Yb) and other LaM{sup 3+}O{sub 3} (M=In, Sc, Ga, Al, Fe and Cr) perovskites. - Highlights: • Interlanthanide perovskites were synthesized by solid state reactions. • Their enthalpies of formation were measured by oxide melt solution calorimetry. • ΔH{sub f,ox} shows a linear relationship with tolerance factor.

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

Vapor pressures and standard molar enthalpies, entropies, and Gibbs free energies of sublimation of 2,4- and 3,4-dinitrobenzoic acids

International Nuclear Information System (INIS)

Vecchio, Stefano; Brunetti, Bruno

2009-01-01

The vapor pressures of the solid and liquid 2,4- and 3,4-dinitrobenzoic acids were determined by torsion-effusion and thermogravimetry under both isothermal and non-isothermal conditions, respectively. From the temperature dependence of vapor pressure derived by the experimental torsion-effusion and thermogravimetry data the molar enthalpies of sublimation Δ cr g H m 0 ( ) and vaporization Δ l g H m 0 ( ) were determined, respectively, at the middle of the respective temperature intervals. The melting temperatures and the molar enthalpies of fusion of these compounds were measured by d.s.c. Finally, the results obtained by all the methods proposed were corrected at the reference temperature of 298.15 K using the estimated heat capacity differences between gas and liquid for vaporization experiments and the estimated heat capacity differences between gas and solid for sublimation experiments. Therefore, the averages of the standard (p o = 0.1 MPa) molar enthalpies, entropies and Gibbs free energies of sublimation at 298.15 K, have been derived.

Analyzing Array Manipulating Programs by Program Transformation

Science.gov (United States)

Cornish, J. Robert M.; Gange, Graeme; Navas, Jorge A.; Schachte, Peter; Sondergaard, Harald; Stuckey, Peter J.

2014-01-01

We explore a transformational approach to the problem of verifying simple array-manipulating programs. Traditionally, verification of such programs requires intricate analysis machinery to reason with universally quantified statements about symbolic array segments, such as "every data item stored in the segment A[i] to A[j] is equal to the corresponding item stored in the segment B[i] to B[j]." We define a simple abstract machine which allows for set-valued variables and we show how to translate programs with array operations to array-free code for this machine. For the purpose of program analysis, the translated program remains faithful to the semantics of array manipulation. Based on our implementation in LLVM, we evaluate the approach with respect to its ability to extract useful invariants and the cost in terms of code size.

Thermodynamic state, specific heat, and enthalpy function of saturated UO2 vapor between 3,000 K and 5,000 K

International Nuclear Information System (INIS)

Karow, H.U.

1977-02-01

The properties have been determined by means of statistical mechanics. The discussion of the thermodynamic state includes the evaluation of the plasma state and its contribution to the caloric variables-of-state of saturated oxide fuel vapor. Because of the extremely high ion and electron density due to thermal ionization, the ionized component of the fuel vapor does no more represent a perfect kinetic plasma. At temperatures around 5,000 K, UO 2 vapor reaches the collective plasma state and becomes increasingly 'metallic'. - Moreover, the nonuniform molecular equilibrium composition of UO 2 vapor has been taken into account in calculating its caloric functions-of-state. The contribution to specific heat and enthalpy of thermally excited electronic states of the vapor molecules has been derived by means of a Rydberg orbital model of the UO 2 molecule. The resulting enthalpy functions and specific heats for saturated UO 2 vapor of equilibrium composition and that for pure UO 2 gas are compared with the enthalpy and specific heat data of gaseous UO 2 at lower temperatures known from literature. (orig./HP) [de

Analysis of LH Launcher Arrays (Like the ITER One) Using the TOPLHA Code

International Nuclear Information System (INIS)

Maggiora, R.; Milanesio, D.; Vecchi, G.

2009-01-01

TOPLHA (Torino Polytechnic Lower Hybrid Antenna) code is an innovative tool for the 3D/1D simulation of Lower Hybrid (LH) antennas, i.e. accounting for realistic 3D waveguides geometry and for accurate 1D plasma models, and without restrictions on waveguide shape, including curvature. This tool provides a detailed performances prediction of any LH launcher, by computing the antenna scattering parameters, the current distribution, electric field maps and power spectra for any user-specified waveguide excitation. In addition, a fully parallelized and multi-cavity version of TOPLHA permits the analysis of large and complex waveguide arrays in a reasonable simulation time. A detailed analysis of the performances of the proposed ITER LH antenna geometry has been carried out, underlining the strong dependence of the antenna input parameters with respect to plasma conditions. A preliminary optimization of the antenna dimensions has also been accomplished. Electric current distribution on conductors, electric field distribution at the interface with plasma, and power spectra have been calculated as well. The analysis shows the strong capabilities of the TOPLHA code as a predictive tool and its usefulness to LH launcher arrays detailed design.

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...

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…

Detachably assembled microfluidic device for perfusion culture and post-culture analysis of a spheroid array.

Science.gov (United States)

Sakai, Yusuke; Hattori, Koji; Yanagawa, Fumiki; Sugiura, Shinji; Kanamori, Toshiyuki; Nakazawa, Kohji

2014-07-01

Microfluidic devices permit perfusion culture of three-dimensional (3D) tissue, mimicking the flow of blood in vascularized 3D tissue in our body. Here, we report a microfluidic device composed of a two-part microfluidic chamber chip and multi-microwell array chip able to be disassembled at the culture endpoint. Within the microfluidic chamber, an array of 3D tissue aggregates (spheroids) can be formed and cultured under perfusion. Subsequently, detailed post-culture analysis of the spheroids collected from the disassembled device can be performed. This device facilitates uniform spheroid formation, growth analysis in a high-throughput format, controlled proliferation via perfusion flow rate, and post-culture analysis of spheroids. We used the device to culture spheroids of human hepatocellular carcinoma (HepG2) cells under two controlled perfusion flow rates. HepG2 spheroids exhibited greater cell growth at higher perfusion flow rates than at lower perfusion flow rates, and exhibited different metabolic activity and mRNA and protein expression under the different flow rate conditions. These results show the potential of perfusion culture to precisely control the culture environment in microfluidic devices. The construction of spheroid array chambers allows multiple culture conditions to be tested simultaneously, with potential applications in toxicity and drug screening. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Array capabilities and future arrays

International Nuclear Information System (INIS)

Radford, D.

1993-01-01

Early results from the new third-generation instruments GAMMASPHERE and EUROGAM are confirming the expectation that such arrays will have a revolutionary effect on the field of high-spin nuclear structure. When completed, GAMMASHPERE will have a resolving power am order of magnitude greater that of the best second-generation arrays. When combined with other instruments such as particle-detector arrays and fragment mass analysers, the capabilites of the arrays for the study of more exotic nuclei will be further enhanced. In order to better understand the limitations of these instruments, and to design improved future detector systems, it is important to have some intelligible and reliable calculation for the relative resolving power of different instrument designs. The derivation of such a figure of merit will be briefly presented, and the relative sensitivities of arrays currently proposed or under construction presented. The design of TRIGAM, a new third-generation array proposed for Chalk River, will also be discussed. It is instructive to consider how far arrays of Compton-suppressed Ge detectors could be taken. For example, it will be shown that an idealised open-quote perfectclose quotes third-generation array of 1000 detectors has a sensitivity an order of magnitude higher again than that of GAMMASPHERE. Less conventional options for new arrays will also be explored

Bayesian Statistical Mechanics: Entropy-Enthalpy Compensation and Universal Equation of State at the Tip of Pen

Directory of Open Access Journals (Sweden)

Evgeni B. Starikov

2018-02-01

Full Text Available This work has shown the way to put the formal statistical-mechanical basement under the hotly debated notion of enthalpy-entropy compensation. The possibility of writing down the universal equation of state based upon the statistical mechanics is discussed here.

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...

On the Possibility of Calculating Entropy, Free Energy, and Enthalpy of Vitreous Substances

Directory of Open Access Journals (Sweden)

Sergei V. Nemilov

2018-03-01

Full Text Available A critical analysis for the arguments in support of, and against, the traditional approach to thermodynamics of vitreous state is provided. In this approach one presumes that there is a continuous variation of the entropy in the glass-liquid transition temperature range, or a “continuous entropy approach” towards 0 K which produces a positive value of the entropy at T → 0 K. I find that arguments given against this traditional approach use a different understanding of the thermodynamics of glass transition on cooling a liquid, because it suggests a discontinuity or “entropy loss approach” in the variation of entropy in the glass-liquid transition range. That is based on: (1 an unjustifiable use of the classical Boltzmann statistics for interpreting the value of entropy at absolute zero; (2 the rejection of thermodynamic analysis of systems with broken ergodicity, even though the possibility of analogous analysis was proposed already by Gibbs; (3 the possibility of a finite change in entropy of a system without absorption or release of heat; and, (4 describing the thermodynamic properties of glasses in the framework of functions, instead of functionals. The last one is necessary because for glasses the entropy and enthalpy are not functions of the state, but functionals, as defined by Gibbs’ in his classification.

Prediction of enthalpy of fusion of pure compounds using an Artificial Neural Network-Group Contribution method

International Nuclear Information System (INIS)

Gharagheizi, Farhad; Salehi, Gholam Reza

2011-01-01

Highlights: → An Artificial Neural Network-Group Contribution method is presented for prediction of enthalpy of fusion of pure compounds at their normal melting point. → Validity of the model is confirmed using a large evaluated data set containing 4157 pure compounds. → The average percent error of the model is equal to 2.65% in comparison with the experimental data. - Abstract: In this work, the Artificial Neural Network-Group Contribution (ANN-GC) method is applied to estimate the enthalpy of fusion of pure chemical compounds at their normal melting point. 4157 pure compounds from various chemical families are investigated to propose a comprehensive and predictive model. The obtained results show the Squared Correlation Coefficient (R 2 ) of 0.999, Root Mean Square Error of 0.82 kJ/mol, and average absolute deviation lower than 2.65% for the estimated properties from existing experimental values.

Clinical utility of an array comparative genomic hybridization analysis for Williams syndrome.

Science.gov (United States)

Yagihashi, Tatsuhiko; Torii, Chiharu; Takahashi, Reiko; Omori, Mikimasa; Kosaki, Rika; Yoshihashi, Hiroshi; Ihara, Masahiro; Minagawa-Kawai, Yasuyo; Yamamoto, Junichi; Takahashi, Takao; Kosaki, Kenjiro

2014-11-01

To reveal the relation between intellectual disability and the deleted intervals in Williams syndrome, we performed an array comparative genomic hybridization analysis and standardized developmental testing for 11 patients diagnosed as having Williams syndrome based on fluorescent in situ hybridization testing. One patient had a large 4.2-Mb deletion spanning distally beyond the common 1.5-Mb intervals observed in 10/11 patients. We formulated a linear equation describing the developmental age of the 10 patients with the common deletion; the developmental age of the patient with the 4.2-Mb deletion was significantly below the expectation (developmental age = 0.51 × chronological age). The large deletion may account for the severe intellectual disability; therefore, the use of array comparative genomic hybridization may provide practical information regarding individuals with Williams syndrome. © 2014 Japanese Teratology Society.

An analysis of seismic background noise variation and evaluation of detection capability of Keskin Array (BRTR PS-43) in Turkey

Science.gov (United States)

Bakir, M. E.; Ozel, N. M.; Semin, K. U.

2011-12-01

Bogazici University, Kandilli Observatory and Earthquake Research Institute (KOERI) is currently operating the Keskin seismic array (BRTR-PS 43) located in town Keskin, providing real-time data to IDC. The instrumentaion of seismic array includes six short period borehole seismometers and one broadband borehole seismometer. The seismic background noise variation of Keskin array are studied in order to estimate the local and regional event detection capability in the frequency range from 1 Hz to 10 Hz. The Power density spectrum and also probability density function of Keskin array data were computed for seasonal and diurnal noise variations between 2008 and 2010. The computation will be extended to cover the period between 2005 and 2008. We attempt to determine the precise frequency characteristics of the background noise, which will help us to assess the station sensitivity. Minimum detectable magnitude versus distance for Keskin seismic array will be analyzed based on the seismic noise analysis. Detailed analysis results of seismic background noise and detection capability will be presented by this research.

Second-order Data by Flow Injection Analysis with Spectrophotometric Diode-array Detection and Incorporated Gel-filtration Chromatographic Column

DEFF Research Database (Denmark)

Bechmann, Iben Ellegaard

1997-01-01

A flow injection analysis (FIA) system furnished with a gel-filtration chromatographic column and with photodiode-array detection was used for the generation of second-order data. The system presented is a model system in which the analytes are blue dextran, potassium hexacyanoferrate(III) and he......A flow injection analysis (FIA) system furnished with a gel-filtration chromatographic column and with photodiode-array detection was used for the generation of second-order data. The system presented is a model system in which the analytes are blue dextran, potassium hexacyanoferrate...

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…

Hydration–dehydration behavior and thermodynamics of MX-80 montmorillonite studied using thermal analysis

Energy Technology Data Exchange (ETDEWEB)

Tajeddine, L. [CNRS-IC2MP-UMR- Hydrasa, 5 Ave Albert, Turpain, (France); Gailhanou, H.; Blanc, P.; Lassin, A.; Gaboreau, S. [BRGM, 3 Av. Claude Guillemin, BP6009, Orléans F-45060 (France); Vieillard, P., E-mail: philippe.vieillard@univ-poitiers.fr [CNRS-IC2MP-UMR- Hydrasa, 5 Ave Albert, Turpain, (France)

2015-03-20

Highlights: • Adsorption–desorption of water on MX-80 is determined from TGA and DTA analysis. • From DTA analysis, three types of water behavior exist at various hydration states. • Surface area of DTA allows to determine the dehydration enthalpy per mole of water. • A maximum enthalpy is 12 kJ/mol for the adsorption and desorption processes. • Enthalpy of formation of water for adsorption and desorption processes are provided. - Abstract: The thermal dehydration of natural bentonite clay MX-80 chosen as a possible future backfill material, was investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The aim of this work is to provide a better understanding of the thermodynamics of the hydration–dehydration process of MX-80. The data obtained from thermogravimetry derivative curves at different relative humidities were used to determine the adsorption–desorption isotherm of MX-80. The total amount of water varies from 0.35 to 5.62 and from 0.78 to 6.12 mol adsorbed H{sub 2}O/mol of clay upon adsorption and desorption, respectively, for a RH between 11 and 91%. Furthermore, the heats released upon adsorption and desorption are not completely similar. Moreover, the analysis of DTA signals obtained at various hydration states provides insights about three types of water behavior in MX-80. Therefore, the surface area of DTA curves was taken into account to determine the dehydration enthalpy per mole of water; the values do not correlate with the amount of adsorbed water in MX-80, and the maximum enthalpy was approximately 12 kJ/mol for the adsorption and desorption studies. The values obtained were combined with the standard enthalpies of the formation of liquid water to obtain the corresponding enthalpy of the formation of water relative to dehydrated MX-80.

Adaptive Injection-locking Oscillator Array for RF Spectrum Analysis

International Nuclear Information System (INIS)

Leung, Daniel

2011-01-01

A highly parallel radio frequency receiver using an array of injection-locking oscillators for on-chip, rapid estimation of signal amplitudes and frequencies is considered. The oscillators are tuned to different natural frequencies, and variable gain amplifiers are used to provide negative feedback to adapt the locking band-width with the input signal to yield a combined measure of input signal amplitude and frequency detuning. To further this effort, an array of 16 two-stage differential ring oscillators and 16 Gilbert-cell mixers is designed for 40-400 MHz operation. The injection-locking oscillator array is assembled on a custom printed-circuit board. Control and calibration is achieved by on-board microcontroller.

Production, pathways and budgets of melts in mid-ocean ridges: An enthalpy based thermo-mechanical model

Science.gov (United States)

Mandal, Nibir; Sarkar, Shamik; Baruah, Amiya; Dutta, Urmi

2018-04-01

Using an enthalpy based thermo-mechanical model we provide a theoretical evaluation of melt production beneath mid-ocean ridges (MORs), and demonstrate how the melts subsequently develop their pathways to sustain the major ridge processes. Our model employs a Darcy idealization of the two-phase (solid-melt) system, accounting enthalpy (ΔH) as a function of temperature dependent liquid fraction (ϕ). Random thermal perturbations imposed in this model set in local convection that drive melts to flow through porosity controlled pathways with a typical mushroom-like 3D structure. We present across- and along-MOR axis model profiles to show the mode of occurrence of melt-rich zones within mushy regions, connected to deeper sources by single or multiple feeders. The upwelling of melts experiences two synchronous processes: 1) solidification-accretion, and 2) eruption, retaining a large melt fraction in the framework of mantle dynamics. Using a bifurcation analysis we determine the threshold condition for melt eruption, and estimate the potential volumes of eruptible melts (∼3.7 × 106 m3/yr) and sub-crustal solidified masses (∼1-8.8 × 106 m3/yr) on an axis length of 500 km. The solidification process far dominates over the eruption process in the initial phase, but declines rapidly on a time scale (t) of 1 Myr. Consequently, the eruption rate takes over the solidification rate, but attains nearly a steady value as t > 1.5 Myr. We finally present a melt budget, where a maximum of ∼5% of the total upwelling melt volume is available for eruption, whereas ∼19% for deeper level solidification; the rest continue to participate in the sub-crustal processes.

Enthalpies of formation of europium alkoxides: What lessons can be drawn from them

International Nuclear Information System (INIS)

Branco, Joaquim B.; Carretas, José M.; Epple, Matthias; Cruz, Adelaide; Pires de Matos, A.; Leal, João Paulo

2014-01-01

Highlights: • First time measurement of europium(II) alkoxides enthalpy of formation. • Calculation of alkoxides thermochemical radii and M–O distances in this environment. • Comparison of experimental EXAFS distance with the calculated ones. • Hints on the type of bond existing in these compounds. • Correlation of bond type and possible use as catalysts. - Abstract: The synthesis and characterization of two europium alkoxides, Eu(OCH 3 ) 2 and Eu(OC 2 H 5 ) 2 , were described. For the first time the enthalpies of formation of divalent lanthanide alkoxides were determined by using reaction-solution calorimetry. The values obtained are Δ f H 0 [Eu(OCH 3 ) 2 ,cr] = −850.5 ± 5.0 kJ/mol and Δ f H 0 [Eu(OC 2 H 5 ) 2 ,cr] = −902.5 ± 5.5 kJ/mol, respectively. Since these compounds have a large use as catalysts or catalysts precursors, the first step of the reaction of them with CO 2 was addressed, which permits to have an idea of the kind of bond involved in those compounds. Moreover, insertion of CO 2 in the europium oxygen bond and formation of metal carboxylate complexes, is in both cases presumably bidentate

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....

Array coding for large data memories

Science.gov (United States)

Tranter, W. H.

1982-01-01

It is pointed out that an array code is a convenient method for storing large quantities of data. In a typical application, the array consists of N data words having M symbols in each word. The probability of undetected error is considered, taking into account three symbol error probabilities which are of interest, and a formula for determining the probability of undetected error. Attention is given to the possibility of reading data into the array using a digital communication system with symbol error probability p. Two different schemes are found to be of interest. The conducted analysis of array coding shows that the probability of undetected error is very small even for relatively large arrays.

Simulations of nanocrystals under pressure: Combining electronic enthalpy and linear-scaling density-functional theory

Energy Technology Data Exchange (ETDEWEB)

Corsini, Niccolò R. C., E-mail: niccolo.corsini@imperial.ac.uk; Greco, Andrea; Haynes, Peter D. [Department of Physics and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Hine, Nicholas D. M. [Department of Physics and Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Cavendish Laboratory, J. J. Thompson Avenue, Cambridge CB3 0HE (United Kingdom); Molteni, Carla [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom)

2013-08-28

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 simulations. We introduce an approach for calibrating the parameters defining the volume in the context of geometry optimizations and discuss their significance. Results in good agreement with simulations using explicit solvents are obtained, validating our approach. Size-dependent pressure-induced structural transformations and variations in the energy gap of hydrogenated silicon nanocrystals are investigated, including one comparable in size to recent experiments. A detailed analysis of the polyamorphic transformations reveals three types of amorphous structures and their persistence on depressurization is assessed.

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

International Nuclear Information System (INIS)

Goldfarb, Jillian L.; Suuberg, Eric M.

2010-01-01

The vapor pressures of seven heteroatom-containing cyclic aromatic hydrocarbons, ranging in molecular weight from (168.19 to 208.21) g . mol -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.

Enthalpy of solution of α- and β-cyclodextrin in water and in some organic solvents

International Nuclear Information System (INIS)

Belica, Sylwia; Sadowska, Monika; Stępniak, Artur; Graca, Anna; Pałecz, Bartłomiej

2014-01-01

Highlights: • A great influence of crystalline water on the energetic of dissolving compounds. • The strongest interaction between β-cyclodextrin and DMSO. • The enthalpic pair interaction coefficient, h βCD-EtOH , obtained is positive. • Predominating effects of the partial dehydration of the molecules – βCD-EtOH. -- Abstract: The calorimetric measurements of solution enthalpy of α-cyclodextrin, β-cyclodextrin in water (H 2 O), dimetyloformamid (DMF), dimethyl sulfoxide (DMSO) and aqueous ethanol solutions (H 2 O + EtOH) at 298.15 K were made. The experimental results were used to calculate the enthalpic coefficients of the interactions between cyclodextrin and ethanol molecules in water based on McMillan–Mayer’s model. The results were compared with literature data and with hydrodynamic radii of cyclodextrin in examined solvents and with donor numbers of these solvents. In order to check, if the inclusion complex formation between the solvent with the highest enthalpy of solution and cyclodextrin has happened, the calorimetric isothermal titration measurements were made and the results were interpreted

Probe suppression in conformal phased array

CERN Document Server

Singh, Hema; Neethu, P S

2017-01-01

This book considers a cylindrical phased array with microstrip patch antenna elements and half-wavelength dipole antenna elements. The effect of platform and mutual coupling effect is included in the analysis. The non-planar geometry is tackled by using Euler's transformation towards the calculation of array manifold. Results are presented for both conducting and dielectric cylinder. The optimal weights obtained are used to generate adapted pattern according to a given signal scenario. It is shown that array along with adaptive algorithm is able to cater to an arbitrary signal environment even when the platform effect and mutual coupling is taken into account. This book provides a step-by-step approach for analyzing the probe suppression in non-planar geometry. Its detailed illustrations and analysis will be a useful text for graduate and research students, scientists and engineers working in the area of phased arrays, low-observables and stealth technology.

Scattering Analysis of a Compact Dipole Array with Series and Parallel Feed Network including Mutual Coupling Effect

Directory of Open Access Journals (Sweden)

H. L. Sneha

2013-01-01

Full Text Available The current focus in defense arena is towards the stealth technology with an emphasis to control the radar cross-section (RCS. The scattering from the antennas mounted over the platform is of prime importance especially for a low-observable aerospace vehicle. This paper presents the analysis of the scattering cross section of a uniformly spaced linear dipole array. Two types of feed networks, that is, series and parallel feed networks, are considered. The total RCS of phased array with either kind of feed network is obtained by following the signal as it enters through the aperture and travels through the feed network. The RCS estimation of array is done including the mutual coupling effect between the dipole elements in three configurations, that is, side-by-side, collinear, and parallel-in-echelon. The results presented can be useful while designing a phased array with optimum performance towards low observability.

Facing the challenge of predicting the standard formation enthalpies of n-butyl-phosphate species with ab initio methods

Science.gov (United States)

Saab, Mohamad; Réal, Florent; Šulka, Martin; Cantrel, Laurent; Virot, François; Vallet, Valérie

2017-06-01

Tributyl-phosphate (TBP), a ligand used in the PUREX liquid-liquid separation process of spent nuclear fuel, can form an explosive mixture in contact with nitric acid that might lead to a violent explosive thermal runaway. In the context of safety of a nuclear reprocessing plant facility, it is crucial to predict the stability of TBP at elevated temperatures. So far, only the enthalpies of formation of TBP are available in the literature with rather large uncertainties, while those of its degradation products, di-(HDBP) and mono-(H2MBP), are unknown. In this goal, we have used state-of-the art quantum chemical methods to compute the formation enthalpies and entropies of TBP and its degradation products di-(HDBP) and mono-(H2MBP) in gas and liquid phases. Comparisons of levels of quantum chemical theory revealed that there are significant effects of correlation on their electronic structures, pushing for the need of not only high level of electronic correlation treatment, namely, local coupled cluster with single and double excitation operators and perturbative treatment of triple excitations, but also extrapolations to the complete basis to produce reliable and accurate thermodynamics data. Solvation enthalpies were computed with the conductor-like screening model for real solvents [COSMO-RS], for which we observe errors not exceeding 22 kJ mol-1. We thus propose with final uncertainty of about 20 kJ mol-1 standard enthalpies of formation of TBP, HDBP, and H2MBP which amounts to -1281.7 ± 24.4, -1229.4 ± 19.6, and -1176.7 ± 14.8 kJ mol-1, respectively, in the gas phase. In the liquid phase, the predicted values are -1367.3 ± 24.4, -1348.7 ± 19.6, and -1323.8± 14.8 kJ mol-1, to which we may add about -22 kJ mol-1 error from the COSMO-RS solvent model. From these data, the complete hydrolysis of TBP is predicted as an exothermic phenomena but showing a slightly endergonic process.

Dynamical analysis of surface-insulated planar wire array Z-pinches

Science.gov (United States)

Li, Yang; Sheng, Liang; Hei, Dongwei; Li, Xingwen; Zhang, Jinhai; Li, Mo; Qiu, Aici

2018-05-01

The ablation and implosion dynamics of planar wire array Z-pinches with and without surface insulation are compared and discussed in this paper. This paper first presents a phenomenological model named the ablation and cascade snowplow implosion (ACSI) model, which accounts for the ablation and implosion phases of a planar wire array Z-pinch in a single simulation. The comparison between experimental data and simulation results shows that the ACSI model could give a fairly good description about the dynamical characteristics of planar wire array Z-pinches. Surface insulation introduces notable differences in the ablation phase of planar wire array Z-pinches. The ablation phase is divided into two stages: insulation layer ablation and tungsten wire ablation. The two-stage ablation process of insulated wires is simulated in the ACSI model by updating the formulas describing the ablation process.

AnovArray: a set of SAS macros for the analysis of variance of gene expression data

Directory of Open Access Journals (Sweden)

Renard Jean-Paul

2005-06-01

Full Text Available Abstract Background Analysis of variance is a powerful approach to identify differentially expressed genes in a complex experimental design for microarray and macroarray data. The advantage of the anova model is the possibility to evaluate multiple sources of variation in an experiment. Results AnovArray is a package implementing ANOVA for gene expression data using SAS® statistical software. The originality of the package is 1 to quantify the different sources of variation on all genes together, 2 to provide a quality control of the model, 3 to propose two models for a gene's variance estimation and to perform a correction for multiple comparisons. Conclusion AnovArray is freely available at http://www-mig.jouy.inra.fr/stat/AnovArray and requires only SAS® statistical software.

Terabyte IDE RAID-5 Disk Arrays

Energy Technology Data Exchange (ETDEWEB)

David A. Sanders et al.

2003-09-30

High energy physics experiments are currently recording large amounts of data and in a few years will be recording prodigious quantities of data. New methods must be developed to handle this data and make analysis at universities possible. We examine some techniques that exploit recent developments in commodity hardware. We report on tests of redundant arrays of integrated drive electronics (IDE) disk drives for use in offline high energy physics data analysis. IDE redundant array of inexpensive disks (RAID) prices now are less than the cost per terabyte of million-dollar tape robots! The arrays can be scaled to sizes affordable to institutions without robots and used when fast random access at low cost is important.

Efficient Full-Wave Analysis of Waveguide Arrays on Cylindrical Surfaces.

NARCIS (Netherlands)

Gerini, G.; Guglielmi, M.; Rozzi, T.; Zappelli, L.

1999-01-01

Conformal open-ended waveguide arrays received great attention in the early seventies. Recently, dielectric loaded waveguide radiators have been again proposed to achieve high dety microwave packaging [1], [2]. The efficient design of highly integrated array solutions, however, require fast and

Hybrid Arrays for Chemical Sensing

Science.gov (United States)

Kramer, Kirsten E.; Rose-Pehrsson, Susan L.; Johnson, Kevin J.; Minor, Christian P.

In recent years, multisensory approaches to environment monitoring for chemical detection as well as other forms of situational awareness have become increasingly popular. A hybrid sensor is a multimodal system that incorporates several sensing elements and thus produces data that are multivariate in nature and may be significantly increased in complexity compared to data provided by single-sensor systems. Though a hybrid sensor is itself an array, hybrid sensors are often organized into more complex sensing systems through an assortment of network topologies. Part of the reason for the shift to hybrid sensors is due to advancements in sensor technology and computational power available for processing larger amounts of data. There is also ample evidence to support the claim that a multivariate analytical approach is generally superior to univariate measurements because it provides additional redundant and complementary information (Hall, D. L.; Linas, J., Eds., Handbook of Multisensor Data Fusion, CRC, Boca Raton, FL, 2001). However, the benefits of a multisensory approach are not automatically achieved. Interpretation of data from hybrid arrays of sensors requires the analyst to develop an application-specific methodology to optimally fuse the disparate sources of data generated by the hybrid array into useful information characterizing the sample or environment being observed. Consequently, multivariate data analysis techniques such as those employed in the field of chemometrics have become more important in analyzing sensor array data. Depending on the nature of the acquired data, a number of chemometric algorithms may prove useful in the analysis and interpretation of data from hybrid sensor arrays. It is important to note, however, that the challenges posed by the analysis of hybrid sensor array data are not unique to the field of chemical sensing. Applications in electrical and process engineering, remote sensing, medicine, and of course, artificial

Characteristics of low-enthalpy geothermal applications in Greece

International Nuclear Information System (INIS)

Andritsos, N.; Dalabakis, P.; Karydakis, G.; Kolios, N.; Fytikas, M.

2011-01-01

The paper offers a brief overview of the current direct geothermal uses in Greece and discusses their characteristics, with emphasis to the economical and technical problems encountered. Greece holds a prominent place in Europe regarding the existence of promising geothermal resources (both high and low-enthalpy), which can be economically exploited. Currently, no geothermal electricity is produced in Greece. The installed capacity of direct uses at the end of 2009 is estimated at about 155 MW t , exhibiting an increase of more than 100% compared to the figures reported at the World Geothermal Congress 2005. The main uses, in decreasing share, are geothermal heat pumps, swimming and balneology, greenhouse heating and soil warming. Earth-coupled and groundwater (or seawater) heat pumps have shown a drastic expansion during the past 2-3 years, mainly due to high oil prices two years ago and easing of the license requirements for drilling shallow wells. (author)

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.)

Thermal analysis for folded solar array of spacecraft in orbit

International Nuclear Information System (INIS)

Yang, W.H.; Cheng, H.E.; Cai, A.

2004-01-01

The combined radiation-conduction heat transfer in folded solar array was considered as a three-dimensional anisotropic conduction without inner heat source. The three-dimensional equivalent conductivity in cell plate were obtained. The especially discrete equation coefficients of the nodes on the surfaces of adjacent cell plates were deduced by utilizing the simplified radiation network among the two adjacent cell plate surfaces and the deep cold space. All the thermal influence factors on the temperature response of the folded solar array were considered carefully. SIP method was used to solve the discrete equation. By comparing the calculation results under three cases, the temperature response and the maximum average difference of the folded solar array was obtained during the period of throw-radome of the launch vehicle and spread of the folded solar array. The obtained result is a valuable reference for the selection of the launch time of the spacecraft

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

Science.gov (United States)

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

2014-11-20

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

Analysis of O-glycans as 9-fluorenylmethyl derivatives and its application to the studies on glycan array.

Science.gov (United States)

Yamada, Keita; Hirabayashi, Jun; Kakehi, Kazuaki

2013-03-19

A method is proposed for the analysis of O-glycans as 9-fluorenylmethyl (Fmoc) derivatives. After releasing the O-glycans from the protein backbone in the presence of ammonia-based media, the glycosylamines thus formed are conveniently labeled with Fmoc-Cl and analyzed by HPLC and MALDI-TOF MS after easy purification. Fmoc labeled O-glycans showed 3.5 times higher sensitivities than those labeled with 2-aminobenzoic acid in fluorescent detection. Various types of O-glycans having sialic acids, fucose, and/or sulfate residues were successfully labeled with Fmoc and analyzed by HPLC and MALDI-TOF MS. The method was applied to the comprehensive analysis of O-glycans expressed on MKN45 cells (human gastric adenocarcinoma). In addition, Fmoc-derivatized O-glycans were easily converted to free hemiacetal or glycosylamine-form glycans that are available for fabrication of glycan array and neoglycoproteins. To demonstrate the availability of our methods, we fabricate the glycan array with Fmoc labeled glycans derived from mucin samples and cancer cells. The model studies using the glycan array showed clear interactions between immobilized glycans and some lectins.

Analysis of mean time to data loss of fault-tolerant disk arrays RAID-6 based on specialized Markov chain

Science.gov (United States)

Rahman, P. A.; D'K Novikova Freyre Shavier, G.

2018-03-01

This scientific paper is devoted to the analysis of the mean time to data loss of redundant disk arrays RAID-6 with alternation of data considering different failure rates of disks both in normal state of the disk array and in degraded and rebuild states, and also nonzero time of the disk replacement. The reliability model developed by the authors on the basis of the Markov chain and obtained calculation formula for estimation of the mean time to data loss (MTTDL) of the RAID-6 disk arrays are also presented. At last, the technique of estimation of the initial reliability parameters and examples of calculation of the MTTDL of the RAID-6 disk arrays for the different numbers of disks are also given.