WorldWideScience

Sample records for base bulges thermodynamic

  1. Thermodynamic examination of 1- to 5-nt purine bulge loops in RNA and DNA constructs.

    Science.gov (United States)

    Strom, Shane; Shiskova, Evgenia; Hahm, Yaeeun; Grover, Neena

    2015-07-01

    Bulge loops are common features of RNA structures that are involved in the formation of RNA tertiary structures and are often sites for interactions with proteins and ions. Minimal thermodynamic data currently exist on the bulge size and sequence effects. Using thermal denaturation methods, thermodynamic properties of 1- to 5-nt adenine and guanine bulge loop constructs were examined in 10 mM MgCl(2) or 1 M KCl. The [Formula: see text] loop parameters for 1- to 5-nt purine bulge loops in RNA constructs were between 3.07 and 5.31 kcal/mol in 1 M KCl buffer. In 10 mM magnesium ions, the ΔΔG° values relative to 1 M KCl were 0.47-2.06 kcal/mol more favorable for the RNA bulge loops. The [Formula: see text] loop parameters for 1- to 5-nt purine bulge loops in DNA constructs were between 4.54 and 5.89 kcal/mol. Only 4- and 5-nt guanine constructs showed significant change in stability for the DNA constructs in magnesium ions. A linear correlation is seen between the size of the bulge loop and its stability. New prediction models are proposed for 1- to 5-nt purine bulge loops in RNA and DNA in 1 M KCl. We show that a significant stabilization is seen for small bulge loops in RNA in the presence of magnesium ions. A prediction model is also proposed for 1- to 5-nt purine bulge loop RNA constructs in 10 mM magnesium chloride. © 2015 Strom et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  2. Galactic bulges

    CERN Document Server

    Peletier, Reynier; Gadotti, Dimitri

    2016-01-01

    This book consists of invited reviews on Galactic Bulges written by experts in the field. A central point of the book is that, while in the standard picture of galaxy formation a significant amount of the baryonic mass is expected to reside in classical bulges, the question what is the fraction of galaxies with no classical bulges in the local Universe has remained open. The most spectacular example of a galaxy with no significant classical bulge is the Milky Way. The reviews of this book attempt to clarify the role of the various types of bulges during the mass build-up of galaxies, based on morphology, kinematics, and stellar populations, and connecting their properties at low and high redshifts. The observed properties are compared with the predictions of the theoretical models, accounting for the many physical processes leading to the central mass concentration and their destruction in galaxies. This book serves as an entry point for PhD students and non-specialists and as a reference work for researchers...

  3. Development of a thermodynamic data base for selected heavy metals

    International Nuclear Information System (INIS)

    Hageman, Sven; Scharge, Tina; Willms, Thomas

    2015-07-01

    The report on the development of a thermodynamic data base for selected heavy metals covers the description of experimental methods, the thermodynamic model for chromate, the thermodynamic model for dichromate, the thermodynamic model for manganese (II), the thermodynamic model for cobalt, the thermodynamic model for nickel, the thermodynamic model for copper (I), the thermodynamic model for copper(II), the thermodynamic model for mercury (0) and mercury (I), the thermodynamic model for mercury (III), the thermodynamic model for arsenate.

  4. REDSHIFT EVOLUTION IN BLACK HOLE-BULGE RELATIONS: TESTING C IV-BASED BLACK HOLE MASSES

    International Nuclear Information System (INIS)

    Greene, Jenny E.; Peng, Chien Y.; Ludwig, Randi R.

    2010-01-01

    We re-examine claims for redshift evolution in black hole-bulge scaling relations based on lensed quasars. In particular, we refine the black hole (BH) mass estimates using measurements of Balmer lines from near-infrared spectroscopy obtained with Triplespec at Apache Point Observatory. In support of previous work, we find a large scatter between Balmer and UV line widths, both Mg IIλλ2796, 2803 and C IVλλ1548, 1550. There is tentative evidence that C III]λ1909, despite being a blend of multiple transitions, may correlate well with Mg II, although a larger sample is needed for a real calibration. Most importantly, we find no systematic changes in the estimated BH masses for the lensed sample based on Balmer lines, providing additional support to the interpretation that black holes were overly massive compared to their host galaxies at high redshift.

  5. Trifunctional fluorescent unnatural nucleoside: Label free detection of T-T/C-C base mismatches, abasic site and bulge DNA.

    Science.gov (United States)

    Bag, Subhendu Sekhar; Pradhan, Manoj Kumar; Talukdar, Sangita

    2017-08-01

    The detection and targeting of both the mismatched and abasic DNA is highly important which would ultimately help in designing new diagnostics and chemotherapeutics. Furthermore, sensing and targeting the bulge sequence with a fluorescent probe would be useful to study the role of bulges in nucleic acid function or could have significant therapeutic potential. Thus, detection of specific bulges by small fluorescent molecules is an attractive research area since the past several years. Many attempts have been made to prepare such compounds. We report herein a label free strategy for the detection of pyrimidine base mismatches (T/T and C/C), sensing of abasic site, and pyrimidine base bulge DNA using an unnatural tetrazolylpyrene nucleoside ( TPy B Do ) as a bare fluorescent probe. The H-bonding/hydrophobic force mediated interactions allow the sensing of all three deformed DNA via an enhancement of fluorescence signal using our simple "Just-Mix and Read" strategy. The binding of the probe to all the three deformed DNA duplexes is accompanied by an increase in the thermal melting stability of the deformed DNAs. That the probe binds efficiently to the minor groove near the deformed site was evident from spectroscopic studies. All the spectral evidences open up a multitude of possibilities for using our probe, tetrazolylpyrene nucleoside, as an efficient fluorescent light-up bio-probe for label free DNA detection. Copyright © 2017. Published by Elsevier B.V.

  6. Thermodynamics

    CERN Document Server

    Fermi, Enrico

    1956-01-01

    Indisputably, this is a modern classic of science. Based on a course of lectures delivered by the author at Columbia University, the text is elementary in treatment and remarkable for its clarity and organization. Although it is assumed that the reader is familiar with the fundamental facts of thermometry and calorimetry, no advanced mathematics beyond calculus is assumed.Partial contents: thermodynamic systems, the first law of thermodynamics (application, adiabatic transformations), the second law of thermodynamics (Carnot cycle, absolute thermodynamic temperature, thermal engines), the entr

  7. Living with a parastomal bulge

    DEFF Research Database (Denmark)

    Krogsgaard, Marianne; Thomsen, Thordis; Vinther, Anders

    2017-01-01

    and readjust stoma care continuously. The physical change called for patients' awareness and posed a threat to patients' control of the ostomy and challenged stoma self-care. The bulge caused a bodily asymmetry that deformed the patients' bodies in a way that exceeded the perceived alteration already caused...... is limited and highly warranted to improve clinical outcome. RELEVANCE TO CLINICAL PRACTICE: The ever-changing bulge posed a threat to patients' control of the ostomy and required specific care from the stoma therapist. Needs-based access to counselling, advice and supplementary materials is important.......AIMS AND OBJECTIVES: To investigate experienced symptoms of parastomal bulging in relation to an ileostomy or colostomy. BACKGROUND: Parastomal bulging is a common complication of stoma formation that can affect patients' physical, psychological and social function. Symptom burdens reported...

  8. Astrid-2 and ground-based observations of the auroral bulge in the middle of the nightside convection throat

    Directory of Open Access Journals (Sweden)

    G. T. Marklund

    2001-06-01

    Full Text Available Results concerning the electrodynamics of the nightside auroral bulge are presented based on simultaneous satellite and ground-based observations. The satellite data include Astrid-2 measurements of electric fields, currents and particles from a midnight auroral oval crossing and Polar UVI images of the large-scale auroral distribution. The ground-based observations include STARE and SuperDARN electric fields and magnetic records from the Greenland and MIRACLE magnetometer network, the latter including stations from northern Scandinavia north to Svalbard. At the time of the Astrid-2 crossing the ground-based data reveal intense electrojet activity, both to the east and west of the Astrid-2 trajectory, related to the Polar observations of the auroral bulge but not necessarily to a typical substorm. The energetic electron fluxes measured by Astrid-2 across the auroral oval were generally weak being consistent with a gap observed in the auroral luminosity distribution. The electric field across the oval was directed westward, intensifying close to the poleward boundary followed by a decrease in the polar cap. The combined observations suggests that Astrid-2 was moving close to the separatrix between the dusk and dawn convection cells in a region of low conductivity. The constant westward direction of the electric field across the oval indicates that current continuity was maintained, not by polarisation electric fields (as in a Cowling channel, but solely by localized up- and downward field-aligned currents in good agreement with the Astrid-2 magnetometer data. The absence of a polarisation electric field and thus of an intense westward closure current between the dawn and dusk convection cells is consistent with the relatively weak precipitation and low conductivity in the convection throat. Thus, the Cowling current model is not adequate for describing the electrodynamics of the nightside auroral bulge treated here.Key words. Ionosphere (auroral

  9. Thermodynamic data-base for metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

    2001-05-01

    This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project.

  10. Thermodynamic data-base for metal fluorides

    International Nuclear Information System (INIS)

    Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

    2001-05-01

    This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project

  11. Fracture prediction in hydraulic bulging of AISI 304 austenitic steel sheets based on a modified ductile fracture criterion

    Science.gov (United States)

    Xu, Y.; Song, H. W.; Zhang, S. H.; Cheng, M.

    2011-08-01

    The demand for weight reduction in modern vehicle construction has resulted in an increase in the application of hydroforming processes for the manufacture of automotive lightweight components. This trend led to the research of evaluation on formability of the sheet or tube hydroforming to be noted, particularly the prediction of fracture. In this study, a new proposed approach based on damage theory for fracture prediction considering the deformation history was introduced. And the modified ductile fracture criterion was applied to predict the failure for hydraulic bulging of AISI 304 austenitic steel sheets. The material parameters in terms of the function of strain rate in the failure criterion were determined from the equivalent fracture strains corresponding tensile tests under different stress conditions. Then, in the finite element simulation the effect of strain rates and their distribution as well during practical sheet metal forming process was considered. The hydraulic bulging tests were carried out to identify the fracture behavior predicted from FE analysis. A comparison between the prediction and experimental results showed that the proposed approach with a modified ductile fracture criteria can give better fracture predictions than traditional ways.

  12. Simulation of disc-bulge-halo galaxies using parallel GPU based codes

    Science.gov (United States)

    Veles, O.; Berczik, P.; Just, A.

    2016-02-01

    We compare the performance of the very popular Tree-GPU code BONSAI with the older Particle-(Multi)Mesh code SUPERBOX. Both code we run on a same hardware using the GPU acceleration for the force calculation. SUPERBOX is a particle-mesh code with high resolution sub-grid and a higher order NGP (nearest grid point) force-calculation scheme. In our research, we are aiming to demonstrate that the new parallel version of SUPERBOX is capable to do the high resolution simulations of the interaction of the system of disc-bulge-halo composed galaxy. We describe the improvement of performance and scalability of SUPERBOX particularly for the Kepler cluster (NVIDIA K20 GPU). A comparison was made with the very popular and publicly available Tree-GPU code BONSAI†.

  13. A constitutive model for magnetostriction based on thermodynamic framework

    International Nuclear Information System (INIS)

    Ho, Kwangsoo

    2016-01-01

    This work presents a general framework for the continuum-based formulation of dissipative materials with magneto–mechanical coupling in the viewpoint of irreversible thermodynamics. The thermodynamically consistent model developed for the magnetic hysteresis is extended to include the magnetostrictive effect. The dissipative and hysteretic response of magnetostrictive materials is captured through the introduction of internal state variables. The evolution rate of magnetostrictive strain as well as magnetization is derived from thermodynamic and dissipative potentials in accordance with the general principles of thermodynamics. It is then demonstrated that the constitutive model is competent to describe the magneto-mechanical behavior by comparing simulation results with the experimental data reported in the literature. - Highlights: • A thermodynamically consistent model is proposed to describe the magneto-mechanical coupling effect. • Internal state variables are introduced to capture the dissipative material response. • The evolution rate of the magnetostrictive strain is derived through thermodynamic and dissipation potentials.

  14. Abundances in the Galactic bulge

    Energy Technology Data Exchange (ETDEWEB)

    Barbuy, B; Alves-Brito, A [Universidade de Sao Paulo, IAG, Rua do Matao 1226, Sao Paulo 05508-900 (Brazil); Ortolani, S; Zoccali, M [Dipartimento di Astronomia, Universita di Padova, Vicolo dell' Osservatorio 2, I-35122 Padova (Italy); Hill, V; Gomez, A [Observatoire de Paris-Meudon, 92195 Meudon Cedex (France); Melendez, J [Centro de AstrofIsica da Universidade de Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Asplund, M [Max Planck Institute for Astrophysics, Postfach 1317, 85741 Garching (Germany); Bica, E [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, CP 15051, Porto Alegre 91501-970 (Brazil); Renzini, A [Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Minniti, D [Department of Astronomy and Astrophysics, Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile)], E-mail: barbuy@astro.iag.usp.br

    2008-12-15

    The metallicity distribution and abundance ratios of the Galactic bulge are reviewed. Issues raised by recent work of different groups, in particular the high metallicity end, the overabundance of {alpha}-elements in the bulge relative to the thick disc and the measurement of giants versus dwarfs, are discussed. Abundances in the old moderately metal-poor bulge globular clusters are described.

  15. Development of a thermodynamic data base for selected heavy metals; Entwicklung einer thermodynamischen Datenbasis fuer ausgewaehlte Schwermetalle

    Energy Technology Data Exchange (ETDEWEB)

    Hageman, Sven; Scharge, Tina; Willms, Thomas

    2015-07-15

    The report on the development of a thermodynamic data base for selected heavy metals covers the description of experimental methods, the thermodynamic model for chromate, the thermodynamic model for dichromate, the thermodynamic model for manganese (II), the thermodynamic model for cobalt, the thermodynamic model for nickel, the thermodynamic model for copper (I), the thermodynamic model for copper(II), the thermodynamic model for mercury (0) and mercury (I), the thermodynamic model for mercury (III), the thermodynamic model for arsenate.

  16. Thermodynamics

    International Nuclear Information System (INIS)

    Zanchini, E.

    1988-01-01

    The definition of energy, in thermodynamics, is dependent by starting operative definitions of the basic concepts of physics on which it rests, such as those of isolated systems, ambient of a system, separable system and set of separable states. Then the definition of energy is rigorously extended to open systems. The extension gives a clear physical meaning to the concept of energy difference between two states with arbitrary different compositions

  17. Recognition of DNA/RNA bulges by antimicrobial and antitumor metallohelices.

    Science.gov (United States)

    Malina, Jaroslav; Scott, Peter; Brabec, Viktor

    2015-09-07

    Bulged structures have been identified in nucleic acids and have been shown to be linked to biomolecular processes involved in numerous diseases. Thus, chemical agents with affinity for bulged nucleic acids are of general biological significance. Herein, the mechanism of specific recognition and stabilization of bulged DNA and RNA by helical bimetallic species was established through detailed molecular biophysics and biochemistry assays. These agents, known as 'flexicates', are potential mimetics of α-helical peptides in cancer treatment, exhibiting antimicrobial and antitumor effects. The flexicates have positive impacts on the thermal stability of DNA duplexes containing bulges, which means that the flexicates interact with the duplexes containing bulges, and that these interactions stabilize the secondary structures of these duplexes. Notably, the stabilising effect of the flexicates increases with the size of the bulge, the maximal stabilization is observed for the duplexes containing a bulge composed of at least three bases. The flexicates bind most preferentially to the bulges composed of pyrimidines flanked on both sides also by pyrimidines. It is suggested that it is so because these bulges exhibit greatest conformational variability in comparison with other combinations of bases in the bulge loop and bases flanking the bulge. Finally, the results indicate that there is only one dominant binding site for the flexicates on the DNA and RNA bulges and that the flexicates bind directly to the bulge or in its close proximity. It is also shown that the flexicates effectively bind to RNA duplexes containing the bulged region of HIV-1 TAR RNA.

  18. Thermodynamic Activity-Based Progress Curve Analysis in Enzyme Kinetics.

    Science.gov (United States)

    Pleiss, Jürgen

    2018-03-01

    Macrokinetic Michaelis-Menten models based on thermodynamic activity provide insights into enzyme kinetics because they separate substrate-enzyme from substrate-solvent interactions. Kinetic parameters are estimated from experimental progress curves of enzyme-catalyzed reactions. Three pitfalls are discussed: deviations between thermodynamic and concentration-based models, product effects on the substrate activity coefficient, and product inhibition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Binding thermodynamics discriminates fragments from druglike compounds: a thermodynamic description of fragment-based drug discovery.

    Science.gov (United States)

    Williams, Glyn; Ferenczy, György G; Ulander, Johan; Keserű, György M

    2017-04-01

    Small is beautiful - reducing the size and complexity of chemical starting points for drug design allows better sampling of chemical space, reveals the most energetically important interactions within protein-binding sites and can lead to improvements in the physicochemical properties of the final drug. The impact of fragment-based drug discovery (FBDD) on recent drug discovery projects and our improved knowledge of the structural and thermodynamic details of ligand binding has prompted us to explore the relationships between ligand-binding thermodynamics and FBDD. Information on binding thermodynamics can give insights into the contributions to protein-ligand interactions and could therefore be used to prioritise compounds with a high degree of specificity in forming key interactions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Diagnostics of gas turbines based on changes in thermodynamics parameters

    Science.gov (United States)

    Hocko, Marián; Klimko, Marek

    2016-03-01

    This article is focused on solving the problems of determining the true state of gas turbine based on measured changes in thermodynamic parameters. Dependence between the real individual parts for gas turbines and changing the thermodynamic parameters were experimentally verified and confirmed on a small jet engine MPM-20 in the laboratory of the Department of Aviation Engineering at Technical University in Košice. The results of experiments confirm that the wear and tear of basic parts for gas turbines (turbo-compressor engines) to effect the change of thermodynamic parameters of the engine.

  1. Diagnostics of gas turbines based on changes in thermodynamics parameters

    Directory of Open Access Journals (Sweden)

    Hocko Marián

    2016-01-01

    Full Text Available This article is focused on solving the problems of determining the true state of gas turbine based on measured changes in thermodynamic parameters. Dependence between the real individual parts for gas turbines and changing the thermodynamic parameters were experimentally verified and confirmed on a small jet engine MPM-20 in the laboratory of the Department of Aviation Engineering at Technical University in Košice. The results of experiments confirm that the wear and tear of basic parts for gas turbines (turbo-compressor engines to effect the change of thermodynamic parameters of the engine.

  2. Combined thermodynamic study of nickel-base alloys. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, C. R.; Meschter, P. J.

    1981-02-15

    Achievements during this period are the following: (1) initiation of a high-temperature study of the Ni-Ta system using the galvanic cell technique, (2) emf study of high-temperature thermodynamics in the Ni-Mo system, (3) measured heat capacity data on ordered and disordered Ni/sub 4/Mo, (4) heat capacities of Ni and disordered Ni/sub 3/Fe, and (5) computer correlation of thermodynamic and phase diagram data in binary Ni-base alloys. (MOW)

  3. Combined thermodynamic study of nickel-base alloys. Progress report

    International Nuclear Information System (INIS)

    Brooks, C.R.; Meschter, P.J.

    1981-01-01

    Achievements during this period are the following: (1) initiation of a high-temperature study of the Ni-Ta system using the galvanic cell technique, (2) emf study of high-temperature thermodynamics in the Ni-Mo system, (3) measured heat capacity data on ordered and disordered Ni 4 Mo, (4) heat capacities of Ni and disordered Ni 3 Fe, and (5) computer correlation of thermodynamic and phase diagram data in binary Ni-base alloys

  4. Characterization of Multiaxial Stress-Strain Response of Tube Metal from Double-Sided Hydro-Bulging Test Based on Hosford's 1979 Yield Criterion

    Science.gov (United States)

    Cui, Xiao-Lei; Yang, Zhai-Ping; Wang, Xiao-Song

    2017-05-01

    To further explore the characterization of the multiaxial stress-strain responses of anisotropic tube metal from double-sided hydro-bulging tests, an analytical model for the equivalent stress and equivalent strain calculation was derived based on Hosford's 1979 yield criterion. Furthermore, thin-walled 5052-O aluminum alloy tubes were used to conduct the bulging experiment with an external pressure of 85 MPa. After the experimental data were substituted into the above analytical model, the Voce equation was used to fit the equivalent stress-strain relationship. It is concluded that the stress versus strain curves of the 5052-O tubes are strongly dependent on the loaded stress states, the adopted yield criteria, and the anisotropy coefficients. The external pressure of 85 MPa had little or no effect on the stress versus strain curves of the tubes, but the locations of the multiaxial stress versus strain curves were lower than that of the uniaxial stress versus strain curve. Moreover, the curve from Hosford's 1979 yield criterion not only had a higher saturation stress and material constant value than the curve from Mises and Hill's 1948 yield criteria but also had a dependence on the anisotropy coefficient.

  5. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P.G.; Bassa, C. G.; Dieball, A.; Greiss, S.; Maccarone, T. J.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Britt, C. T.; Clem, J. L.; Gossen, L.; Grindlay, J. E.; Groot, P.J.; Kuiper, L.; Kuulkers, E.; Mendez, M.; Mikles, V. J.; Ratti, E. M.; Rea, N.; van Haaften, L.; Wijnands, R.; in't Zand, J. J. M.

    The Chandra Galactic Bulge Survey (CGBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  6. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P. G.; Bassa, C. G.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Maccarone, T. J.; Greiss, S.; Clem, J.; Dieball, A.; Mikles, V. J.; Britt, C. T.; Gossen, L.; Collazzi, A. C.; Wijnands, R.; In't Zand, J. J. M.; Mendez, M.; Rea, N.; Kuulkers, E.; Ratti, E. M.; van Haaften, L. M.; Heinke, C.; Ozel, F.; Groot, P. J.; Verbunt, F.

    2012-01-01

    The Chandra Galactic Bulge Survey (GBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  7. The Chandra Galactic Bulge Survey

    NARCIS (Netherlands)

    Hynes, Robert I.; Jonker, P. G.; Bassa, C. G.; Nelemans, G.; Steeghs, D.; Torres, M. A. P.; Maccarone, T. J.; Greiss, S.; Clem, J.; Dieball, A.; Mikles, V. J.; Britt, C. T.; Gossen, L.; Collazzi, A. C.; Wijnands, R.; In't Zand, J. J. M.; Mendez, M.; Rea, N.; Kuulkers, E.; Ratti, E. M.; van Haaften, L. M.; Heinke, C.; Ozel, F.; Groot, P. J.; Verbunt, F.

    The Chandra Galactic Bulge Survey (GBS) is a shallow but wide survey of two approximately 6x1 degree strips of the Galactic Bulge about a degree above and below the plane. The survey by design targets regions where extinction and crowding are manageable and optical counterparts are accessible to

  8. Grid sleeve bulge tool

    International Nuclear Information System (INIS)

    Phillips, W.D.; Vaill, R.E.

    1980-01-01

    An improved grid sleeve bulge tool is designed for securing control rod guide tubes to sleeves brazed in a fuel assembly grid. The tool includes a cylinder having an outer diameter less than the internal diameter of the control rod guide tubes. The walls of the cylinder are cut in an axial direction along its length to provide several flexible tines or ligaments. These tines are similar to a fork except they are spaced in a circumferential direction. The end of each alternate tine is equipped with a semispherical projection which extends radially outwardly from the tine surface. A ram or plunger of generally cylindrical configuration and about the same length as the cylinder is designed to fit in and move axially of the cylinder and thereby force the tined projections outwardly when the ram is pulled into the cylinder. The ram surface includes axially extending grooves and plane surfaces which are complimentary to the inner surfaces formed on the tines on the cylinder. As the cylinder is inserted into a control rod guide tube, and the projections on the cylinder placed in a position just below or above a grid strap, the ram is pulled into the cylinder, thus moving the tines and the projections thereon outwardly into contact with the sleeve, to plastically deform both the sleeve and the control rod guide tube, and thereby form four bulges which extend outwardly from the sleeve surface and beyond the outer periphery of the grid peripheral strap. This process is then repeated at the points above the grid to also provide for outwardly projecting surfaces, the result being that the grid is accurately positioned on and mechanically secured to the control rod guide tubes which extend the length of a fuel assembly

  9. Age bimodality in the central region of pseudo-bulges in S0 galaxies

    Science.gov (United States)

    Mishra, Preetish K.; Barway, Sudhanshu; Wadadekar, Yogesh

    2017-11-01

    We present evidence for bimodal stellar age distribution of pseudo-bulges of S0 galaxies as probed by the Dn(4000) index. We do not observe any bimodality in age distribution for pseudo-bulges in spiral galaxies. Our sample is flux limited and contains 2067 S0 and 2630 spiral galaxies drawn from the Sloan Digital Sky Survey. We identify pseudo-bulges in S0 and spiral galaxies, based on the position of the bulge on the Kormendy diagram and their central velocity dispersion. Dividing the pseudo-bulges of S0 galaxies into those containing old and young stellar populations, we study the connection between global star formation and pseudo-bulge age on the u - r colour-mass diagram. We find that most old pseudo-bulges are hosted by passive galaxies while majority of young bulges are hosted by galaxies that are star forming. Dividing our sample of S0 galaxies into early-type S0s and S0/a galaxies, we find that old pseudo-bulges are mainly hosted by early-type S0 galaxies while most of the pseudo-bulges in S0/a galaxies are young. We speculate that morphology plays a strong role in quenching of star formation in the disc of these S0 galaxies, which stops the growth of pseudo-bulges, giving rise to old pseudo-bulges and the observed age bimodality.

  10. Thermodynamics-based models of transcriptional regulation with gene sequence.

    Science.gov (United States)

    Wang, Shuqiang; Shen, Yanyan; Hu, Jinxing

    2015-12-01

    Quantitative models of gene regulatory activity have the potential to improve our mechanistic understanding of transcriptional regulation. However, the few models available today have been based on simplistic assumptions about the sequences being modeled or heuristic approximations of the underlying regulatory mechanisms. In this work, we have developed a thermodynamics-based model to predict gene expression driven by any DNA sequence. The proposed model relies on a continuous time, differential equation description of transcriptional dynamics. The sequence features of the promoter are exploited to derive the binding affinity which is derived based on statistical molecular thermodynamics. Experimental results show that the proposed model can effectively identify the activity levels of transcription factors and the regulatory parameters. Comparing with the previous models, the proposed model can reveal more biological sense.

  11. Thermodynamics-based Metabolite Sensitivity Analysis in metabolic networks.

    Science.gov (United States)

    Kiparissides, A; Hatzimanikatis, V

    2017-01-01

    The increasing availability of large metabolomics datasets enhances the need for computational methodologies that can organize the data in a way that can lead to the inference of meaningful relationships. Knowledge of the metabolic state of a cell and how it responds to various stimuli and extracellular conditions can offer significant insight in the regulatory functions and how to manipulate them. Constraint based methods, such as Flux Balance Analysis (FBA) and Thermodynamics-based flux analysis (TFA), are commonly used to estimate the flow of metabolites through genome-wide metabolic networks, making it possible to identify the ranges of flux values that are consistent with the studied physiological and thermodynamic conditions. However, unless key intracellular fluxes and metabolite concentrations are known, constraint-based models lead to underdetermined problem formulations. This lack of information propagates as uncertainty in the estimation of fluxes and basic reaction properties such as the determination of reaction directionalities. Therefore, knowledge of which metabolites, if measured, would contribute the most to reducing this uncertainty can significantly improve our ability to define the internal state of the cell. In the present work we combine constraint based modeling, Design of Experiments (DoE) and Global Sensitivity Analysis (GSA) into the Thermodynamics-based Metabolite Sensitivity Analysis (TMSA) method. TMSA ranks metabolites comprising a metabolic network based on their ability to constrain the gamut of possible solutions to a limited, thermodynamically consistent set of internal states. TMSA is modular and can be applied to a single reaction, a metabolic pathway or an entire metabolic network. This is, to our knowledge, the first attempt to use metabolic modeling in order to provide a significance ranking of metabolites to guide experimental measurements. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier

  12. Energy conservation technologies based on thermodynamic principles

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Masaru [Shibaura Institute of Technology of Technology, Tokyo (Japan)

    1996-12-31

    In order to reduce CO{sub 2} emission to prevent global warming, the most promising way for electric generation in the Northeast Asia is to introduce cogeneration and {open_quotes}repowering{close_quotes} technologies based on high temperature gas turbines fueled by natural gas. Especially the old type coal burning boiler-steam turbine plants should be retrofit by introducing gas turbines to become highly efficient combined cycle. Same technologies should be applied to the old garbage incineration plants and/or even to the nuclear power plants. The exhaust heat or steam should become much increased and it should be utilized as the process heat for industries or heat supply as the distinct heating or cooling for residential area. This paper introduces a brief survey of these new technologies.

  13. Youth bulges and youth unemployment

    OpenAIRE

    David Lam

    2014-01-01

    The youth population bulge is often mentioned in discussions of youth unemployment and unrest in developing countries, most recently in explaining the “Arab Spring.” But the youth share of the population has fallen rapidly in recent decades in most countries, and is projected to continue to fall. Evidence on the link between youth population bulges and youth unemployment is mixed. It should not be assumed that declines in the relative size of the youth population will translate into falling y...

  14. Thermodynamic analysis of ecosystem based on remote sensing data

    Science.gov (United States)

    Sandlerskiy, Robert; Puzachenko, Yurii

    2010-05-01

    key words: ecosystem thermodynamic, energy balance, exergy, Transformation of matter and energy in plant associations and their relationship with other parts of the ecosystem are being determined by the physiological processes in plants. Accordingly, to identify general patterns of ecosystem energy transformation, assessment of an energy balance components reflecting the nature of physiological processes: photosynthesis, transpiration (of which carbon balance is evaluated), water and minerals exchange, is required. Assessment of the main energy variables for ecosystems is possible on the basis of information-thermodynamic approach in which the ecosystem - is an open system, producing yield for self-maintenance on its structure through the conversion of solar energy. In doing so, the distribution of energy absorbed by balance components depends on the structure of the system that determines the nonequilibrium energy conversion. In the information-thermodynamic approach essential component in the transformation of solar energy is exergy - the maximum work that a thermodynamic system may commit during its transition from the current state to the state of equilibrium with the environment. Exergy sometimes called system yield, it is the function of the distance between the current state of the system and thermodynamic equilibrium. Relating to ecosystems, exergy - part of absorbed solar energy, spend on biological productivity and evapotranspiration (exergy of solar radiation). The rest goes into the bound energy - energy transition in the heat flow and entropy, and in increment of internal energy - system energy accumulation wich in its turn spend on maintenance of intercomponent and interspecific interactions, local cycles. Get estimation of energy balance for the entire set of ecosystems based on ground-based measurements is virtually impossible. Such assessments are possible on the basis of remote sensing data, which show the energetic state of the Earth's surface at

  15. The GIRAFFE Inner Bulge Survey (GIBS). III. Metallicity distributions and kinematics of 26 Galactic bulge fields

    Science.gov (United States)

    Zoccali, M.; Vasquez, S.; Gonzalez, O. A.; Valenti, E.; Rojas-Arriagada, A.; Minniti, J.; Rejkuba, M.; Minniti, D.; McWilliam, A.; Babusiaux, C.; Hill, V.; Renzini, A.

    2017-03-01

    Galactic bulge, that will help discrimination between different formation models. Based on observations taken with ESO telescopes at the La Silla Paranal Observatory under programme IDs 71.B-0617, 385.B-0735 and 187.B-0909.Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A12

  16. YOUNG STARS IN AN OLD BULGE: A NATURAL OUTCOME OF INTERNAL EVOLUTION IN THE MILKY WAY

    Energy Technology Data Exchange (ETDEWEB)

    Ness, M. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Debattista, Victor P.; Cole, D. R. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Bensby, T.; Feltzing, S. [Lund Observatory, Department of Astronomy and Theoretical Physics, Box 43, SE-221 00 Lund (Sweden); Roškar, R. [Institute for Theoretical Physics, University of Zürich, Wintherthurerstrasse 190, Zürich CH-8057 (Switzerland); Johnson, J. A. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Freeman, K., E-mail: ness@mpia.de [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia)

    2014-06-01

    The center of our disk galaxy, the Milky Way, is dominated by a boxy/peanut-shaped bulge. Numerous studies of the bulge based on stellar photometry have concluded that the bulge stars are exclusively old. The perceived lack of young stars in the bulge strongly constrains its likely formation scenarios, providing evidence that the bulge is a unique population that formed early and separately from the disk. However, recent studies of individual bulge stars using the microlensing technique have reported that they span a range of ages, emphasizing that the bulge may not be a monolithic structure. In this Letter we demonstrate that the presence of young stars that are located predominantly nearer to the plane is expected for a bulge that has formed from the disk via dynamical instabilities. Using an N-body+ smoothed particle hydrodynamics simulation of a disk galaxy forming out of gas cooling inside a dark matter halo and forming stars, we find a qualitative agreement between our model and the observations of younger metal-rich stars in the bulge. We are also able to partially resolve the apparent contradiction in the literature between results that argue for a purely old bulge population and those that show a population comprised of a range in ages; the key is where to look.

  17. Stellar Feedback from Galactic Bulges

    Science.gov (United States)

    Tang, Shikui; Wang, D. Q.

    2009-01-01

    We demonstrate that feedback from galactic bulges can play an essential role in the halo gas dynamics and the evolution of their host galaxies by conducting a series of 1-D and 3-D simulations. In our 1-D models we approximately divide the the bulge stellar feedback into two phases: 1) a starbusrt-induced blastwave from the formation of bulge built up through frequent major mergers at high redshift and 2) a gradual feedback in forms of stellar wind and Type Ia SNe from low mass stars. Our simulations show that the combination of the two-phase feedback can heat the surrounding gas beyond the virial radius and stop further gas accretion, which naturally produces a baryon deficit around MW-like galaxies and explains the lack of large-scale X-ray halos, consistent with observations. The hot gas dynamics depends sensitively on the environment and bulge formation history. This dependency may account for the large dispersion in the X-ray luminosities of the galaxies with similar L_B. In the 3-D simulations, we examine the spatial, thermal, and chemical substructures and their effects on X-ray measurements. The sporadic SN explosion creates wealth of filamentary and shell-like structures in the hot gas and produces a broad lognormal-like emission-measure distribution, which enhances the X-ray emission at a low and high temperatures. The luminosity at 0.3-2.0 keV band is nearly tripled due to the gas structures. We find that the SN Ia ejecta are not well-mixed with the ambient medium within the bulge scale, and the X-ray emission is primarily from shocked stellar wind materials which in general has low metallicity.

  18. Thermodynamic and structural basis for electrochemical response of Cu–Zr based metallic glass

    International Nuclear Information System (INIS)

    Zhang, Chunzhi; Qiu, Nannan; Kong, Lingliang; Yang, Xiaodan; Li, Huiping

    2015-01-01

    Highlights: • Thermodynamic and structural basis for electrochemical response were proposed. • La improves the corrosion resistance by inhibition of the selective dissolution. • Corrosion of the MG responses well with thermodynamic and structural parameters. - Abstract: Cu–Zr based metallic glasses were prepared by hyperquenching strategy to explore the thermodynamic and structural basis for electrochemical response. The thermodynamic parameters and the local atomic structure were obtained. Corrosion resistance in seawater was investigated via potentiodynamic polarization curve. The results indicate that increasing thermodynamic parameter values improves the corrosion resistance. The topological instability represented by the nearest neighbor atomic distance yields same tendency as the corrosion resistance with La addition

  19. Phase transformations and thermodynamics of aluminum-based metallic glasses

    Science.gov (United States)

    Gao, Changhua (Michael)

    This thesis examines the thermodynamics and associated kinetics and phase transformations of the glass forming Al-Ni-Gd and Al-Fe-Gd systems. In order to fully understand the unique glass forming ability (GFA) of Al-based metallic glasses, the ternary Al-Fe-Gd and Al-Ni-Gd systems in their Al-rich corners were examined experimentally to assist in a thermodynamic assessment. The solid-state phase equilibria are determined using XRD and TEM-EDS techniques. While this work basically confirms the solid-state equilibria in Al-Fe-Gd reported previously, the ternary phase in Al-Ni-Gd system has been identified to be Al15Ni3Gd2 rather than Al16Ni 3Gd reported in the literature. DTA analysis of 24 alloys in the Al-Fe-Gd system and 42 alloys in the Al-Ni-Gd system have yielded critical temperatures pertaining to the solid-liquid transition. Based on these data and information from the literature, a self-consistent thermodynamic database for these systems has been developed using the CALPHAD technique. Parameters describing the Gibbs free energy for various phases of the Al-Gd, Al-Fe-Gd and Al-Ni-Gd systems are manually optimized in this study. Once constructed, the database is used to calculate driving forces for nucleation of crystalline phases which can qualitatively explain the phase formation sequence during crystallization at low temperatures. It was also confirmed that alloy compositions with the lowest Gibbs free energy difference between the equilibrium state and undercooled liquid state exhibit better GFA than other chemistries. Based on 250°C isothermal devitrification phase transformations of 17 Al-Ni-Gd alloys, a phase formation sequence map is constructed. Fcc-Al nanocrystals are formed first in most of the alloys studied, but eutectic crystallization of a metastable phase and fcc-Al is also observed. Addition of Al or Ni promotes fcc-Al phase formation, while increasing Gd suppresses it. The continuous heating DSC scans revealed that crystallization in Al

  20. Stability of black holes based on horizon thermodynamics

    Directory of Open Access Journals (Sweden)

    Meng-Sen Ma

    2015-12-01

    Full Text Available On the basis of horizon thermodynamics we study the thermodynamic stability of black holes constructed in general relativity and Gauss–Bonnet gravity. In the framework of horizon thermodynamics there are only five thermodynamic variables E, P, V, T, S. It is not necessary to consider concrete matter fields, which may contribute to the pressure of black hole thermodynamic system. In non-vacuum cases, we can derive the equation of state, P=P(V,T. According to the requirements of stable equilibrium in conventional thermodynamics, we start from these thermodynamic variables to calculate the heat capacity at constant pressure and Gibbs free energy and analyze the local and global thermodynamic stability of black holes. It is shown that P>0 is the necessary condition for black holes in general relativity to be thermodynamically stable, however this condition cannot be satisfied by many black holes in general relativity. For black hole in Gauss–Bonnet gravity negative pressure can be feasible, but only local stable black hole exists in this case.

  1. Insights from Exploring Thermodynamics-Based Artificial Viscosity

    Science.gov (United States)

    Mattsson, Ann E.

    2015-06-01

    Artificial viscosity is a crucial method for handling shock waves numerically in continuum codes. It serves to smoothen the naturally abrupt shock front over several numerical cells, thus enhancing numerical stability of the calculation. I have re-derived, in general terms, the requirements on, and limitations of, the artificial viscosity to produce a stable smoothened shock front and will share insights from this work. In particular, I will discuss which thermodynamic quantities will be needed in an implementation based on this new artificial viscosity concept. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  2. Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

    International Nuclear Information System (INIS)

    Singh, Tejwant; Kumar, Arvind

    2011-01-01

    Research highlights: → The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. → Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. → Viscometric studies revealed studied ionic liquids as water-structure makers. → Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density ρ, speed of sound u, and viscosity η of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [C n mim] having [BF 4 ] - , [Cl] - , [C 1 OSO 3 ] - , and [C 8 OSO 3 ] - as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume φ V , isentropic compressibility β s , and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (V int ) molar electrostriction volume (V elec ), molar disordered (V dis ), and cage volume (V cage ). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

  3. pycalphad: CALPHAD-based Computational Thermodynamics in Python

    Directory of Open Access Journals (Sweden)

    Richard Otis

    2017-01-01

    Full Text Available The pycalphad software package is a free and open-source Python library for designing thermodynamic models, calculating phase diagrams and investigating phase equilibria using the CALPHAD method. It provides routines for reading thermodynamic databases and solving the multi-component, multi-phase Gibbs energy minimization problem. The pycalphad software project advances the state of thermodynamic modeling by providing a flexible yet powerful interface for manipulating CALPHAD data and models. The key feature of the software is that the thermodynamic models of individual phases and their associated databases can be programmatically manipulated and overridden at run-time without modifying any internal solver or calculation code. Because the models are internally decoupled from the equilibrium solver and the models themselves are represented symbolically, pycalphad is an ideal tool for CALPHAD database development and model prototyping.

  4. The Effect of Learning Based on Technology Model and Assessment Technique toward Thermodynamic Learning Achievement

    Science.gov (United States)

    Makahinda, T.

    2018-02-01

    The purpose of this research is to find out the effect of learning model based on technology and assessment technique toward thermodynamic achievement by controlling students intelligence. This research is an experimental research. The sample is taken through cluster random sampling with the total respondent of 80 students. The result of the research shows that the result of learning of thermodynamics of students who taught the learning model of environmental utilization is higher than the learning result of student thermodynamics taught by simulation animation, after controlling student intelligence. There is influence of student interaction, and the subject between models of technology-based learning with assessment technique to student learning result of Thermodynamics, after controlling student intelligence. Based on the finding in the lecture then should be used a thermodynamic model of the learning environment with the use of project assessment technique.

  5. Dust properties in the Galactic bulge

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    Context. It has been suggested that the ratio of total-to-selective extinction R-V in dust in the interstellar medium differs in the Galactic bulge from its value in the local neighborhood. Aims. We attempt to test this suggestion. Methods. The mid-infrared hydrogen lines in 16 Galactic bulge PNe

  6. Optimization of technological parameters in the calescent superplastic bulge forming of Ti-6Al-4V alloys sheet based on fuzzy neural network

    Energy Technology Data Exchange (ETDEWEB)

    Chen, M.H.; Gao, L.; Zuo, D.W.; Wang, M. [Coll. of Mechanical and Electrical Engineering, Nanjing Univ. of Aeronautics and Astronautics, Nanjing (China); Zhu, Z.S. [Beijing Inst. of Aeronautics Materials, Beijing, BJ (China)

    2004-07-01

    The calescent superplastic bulge forming (CSPBF) of Ti-6Al-4V (TC4) alloy sheet was investigated using experimental method, and carried out the research that optimized its technological parameters using fuzzy neural network (FNN). The experimental results show that the CSPBF may save processing time, can also improve materials' formability as well as get ideal microstructure. The study indicated that the FNN adapt to solve complex nonlinear problem such as technological parameters of CSPBF of TC4 sheet. Utilizing optimized technological parameters successfully have formed the part of aerostat, the nonuniformity of wall thickness is less than 8% and part' forming time may be shorten 10minute. (orig.)

  7. German activities towards a thermodynamic reference data base

    International Nuclear Information System (INIS)

    Herbert, H.J.; Hagemann, S.; Brendler, V.; Marquardt, Ch.; Voigt, W.; Wilhelm, S.

    2006-01-01

    Leading research centres in the field of radioactive waste disposal in Germany have decided to combine their efforts in order to achieve a common goal, the development of a comprehensive and consistent thermodynamic reference database. All the thermodynamic data needed for the modelling of geochemical near- and far field processes in the geological media for high level waste repositories presently under discussion in Germany (salt, clay, granite) shall be collected and qualified in a single database. The partners participating in the project are a group of experts, who are generating, collecting and evaluating thermodynamic data of all relevant radionuclides and matrix elements according to uniform previously established and internationally accepted criteria. Special attention will be given to complete documentation and traceability of all data entries in the database. Existing data from international databases such as those of NEA, NAGRA, YMP will be integrated. Ion interaction coefficients (SIT, Pitzer) needed for modelling in a high saline environment will be included also. (authors)

  8. Is neoclassical microeconomics formally valid? An approach based on an analogy with equilibrium thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Tania; Domingos, Tiago [Environment and Energy Section, DEM, Instituto Superior Tecnico, Avenida Rovisco Pais, 1, 1049-001 Lisboa (Portugal)

    2006-06-10

    The relation between Thermodynamics and Economics is a paramount issue in Ecological Economics. Two different levels can be distinguished when discussing it: formal and substantive. At the formal level, a mathematical framework is used to describe both thermodynamic and economic systems. At the substantive level, thermodynamic laws are applied to economic processes. In Ecological Economics, there is a widespread claim that neoclassical economics has the same mathematical formulation as classical mechanics and is therefore fundamentally flawed because: (1) utility does not obey a conservation law as energy does; (2) an equilibrium theory cannot be used to study irreversible processes. Here, we show that neoclassical economics is based on a wrong formulation of classical mechanics, being in fact formally analogous to equilibrium thermodynamics. The similarity between both formalisms, namely that they are both cases of constrained optimisation, is easily perceived when thermodynamics is looked upon using the Tisza-Callen axiomatisation. In this paper, we take the formal analogy between equilibrium thermodynamics and economic systems far enough to answer the formal criticisms, proving that the formalism of neoclassical economics has irreversibility embedded in it. However, the formal similarity between equilibrium thermodynamics and neoclassical microeconomics does not mean that economic models are in accordance with mass, energy and entropy balance equations. In fact, neoclassical theory suffers from flaws in the substantive integration with thermodynamic laws as has already been fully demonstrated by valuable work done by ecological economists in this field. (author)

  9. The GIRAFFE Inner Bulge Survey (GIBS)

    Science.gov (United States)

    Zoccali, M.; Gonzalez, O. A.; Vasquez, S.; Hill, V.; Rejkuba, M.; Valenti, E.; Renzini, A.; Rojas-Arriagada, A.; Babusiaux, C.; Brown, T.; Minniti, D.; McWilliam, A.

    2015-03-01

    The GIRAFFE Inner Bulge Survey (GIBS) is a spectroscopic survey of ~ 6500 core helium burning (red clump) stars in the Milky Way Bulge, carried out with the FLAMES GIRAFFE spectrograph at the VLT. The aim of the GIBS survey is to derive the metallicity and radial velocity distributions of Bulge stars, across 31 fields in the region of Galactic longitude range -10° to +10° and latitude range -10° to +5°. This is the area also mapped by the VISTA Variables in the Vía Láctea (VVV) ESO Public Survey.

  10. Heading in the right direction: thermodynamics-based network analysis and pathway engineering.

    Science.gov (United States)

    Ataman, Meric; Hatzimanikatis, Vassily

    2015-12-01

    Thermodynamics-based network analysis through the introduction of thermodynamic constraints in metabolic models allows a deeper analysis of metabolism and guides pathway engineering. The number and the areas of applications of thermodynamics-based network analysis methods have been increasing in the last ten years. We review recent applications of these methods and we identify the areas that such analysis can contribute significantly, and the needs for future developments. We find that organisms with multiple compartments and extremophiles present challenges for modeling and thermodynamics-based flux analysis. The evolution of current and new methods must also address the issues of the multiple alternatives in flux directionalities and the uncertainties and partial information from analytical methods. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Mechanics, waves and thermodynamics an example-based approach

    CERN Document Server

    Jain, Sudhir Ranjan

    2016-01-01

    The principles of classical physics, though superseded in specific fields by such theories as quantum mechanics and general relativity, are still of great importance in a broad range of applications. The book presents fundamental concepts of classical physics in a coherent and logical manner. It discusses important topics including the mechanics of a single particle, kinetic theory, oscillations and waves. Topics including the kinetic theory of gases, thermodynamics and statistical mechanics are discussed, which are normally not present in the books on classical physics. The fundamental concepts of energy, momentum, mass and entropy are explained with examples. Discussion on concepts of thermodynamics is presented along with the simplified explanation on Caratheodory's axioms. It covers chapters on wave motion and statistical physics, useful for the graduate students. Each concept is supported with real-life applications on several concepts including impulse and collision, Bernoulli's equation, and friction.

  12. ARGOS - II. The Galactic bulge survey

    Science.gov (United States)

    Freeman, K.; Ness, M.; Wylie-de-Boer, E.; Athanassoula, E.; Bland-Hawthorn, J.; Asplund, M.; Lewis, G.; Yong, D.; Lane, R.; Kiss, L.; Ibata, R.

    2013-02-01

    We describe the motivation, field locations and stellar selection for the Abundances and Radial velocity Galactic Origins Survey (ARGOS) spectroscopic survey of 28 000 stars in the bulge and inner disc of the Milky Way galaxy across latitudes of b = -5° to -10°. The primary goal of this survey is to constrain the formation processes of the bulge and establish whether it is predominantly a merger or instability remnant. From the spectra (R = 11 000), we have measured radial velocities and determined stellar parameters, including metallicities and [α/Fe] ratios. Distances were estimated from the derived stellar parameters and about 14 000 stars are red giants within 3.5 kpc of the Galactic Centre. In this paper, we present the observations and analysis methods. Subsequent papers (III and IV) will discuss the stellar metallicity distribution and kinematics of the Galactic bulge and inner disc, and the implications for the formation of the bulge.

  13. Deconstructing bulges in lenticular galaxies using CALIFA

    Science.gov (United States)

    Méndez-Abreu, J.; CALIFA Team

    2015-05-01

    Bulges play a key role in the evolution of disk galaxies and their influence on the fate of lenticular galaxies (S0s) is still more manifest. We present preliminary results on the photometric and kinematic properties of S0 bulges drawn from the CALIFA survey. We find that S0 galaxies usually deviate from their archetypal view of simple systems composed by a bulge and disk structure. In fact, most of S0 galaxies (˜65%) host bars or non-single exponential profiles, making compulsory the use of multi-component photometric decompositions to properly address the bulge properties. We confirm previous results present in the literature showing S0 galaxies as a complete photometric and kinematic sequence of galaxies.

  14. Bulging Fontanelle and Need for Lumbar Puncture

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2009-10-01

    Full Text Available Etiologies of bulging fontanelle and fever and clinical evidence for lumbar puncture were determined from medical records of 153 infants treated at Assaf Harofeh Medical Center, Israel.

  15. Thermodynamically based constraints for rate coefficients of large biochemical networks.

    Science.gov (United States)

    Vlad, Marcel O; Ross, John

    2009-01-01

    Wegscheider cyclicity conditions are relationships among the rate coefficients of a complex reaction network, which ensure the compatibility of kinetic equations with the conditions for thermodynamic equilibrium. The detailed balance at equilibrium, that is the equilibration of forward and backward rates for each elementary reaction, leads to compatibility between the conditions of kinetic and thermodynamic equilibrium. Therefore, Wegscheider cyclicity conditions can be derived by eliminating the equilibrium concentrations from the conditions of detailed balance. We develop matrix algebra tools needed to carry out this elimination, reexamine an old derivation of the general form of Wegscheider cyclicity condition, and develop new derivations which lead to more compact and easier-to-use formulas. We derive scaling laws for the nonequilibrium rates of a complex reaction network, which include Wegscheider conditions as a particular case. The scaling laws for the rates are used for clarifying the kinetic and thermodynamic meaning of Wegscheider cyclicity conditions. Finally, we discuss different ways of using Wegscheider cyclicity conditions for kinetic computations in systems biology.

  16. Comparative Analysis of Bulge Deformation between 2D and 3D Finite Element Models

    Directory of Open Access Journals (Sweden)

    Qin Qin

    2014-02-01

    Full Text Available Bulge deformation of the slab is one of the main factors that affect slab quality in continuous casting. This paper describes an investigation into bulge deformation using ABAQUS to model the solidification process. A three-dimensional finite element analysis model of the slab solidification process has been first established because the bulge deformation is closely related to slab temperature distributions. Based on slab temperature distributions, a three-dimensional thermomechanical coupling model including the slab, the rollers, and the dynamic contact between them has also been constructed and applied to a case study. The thermomechanical coupling model produces outputs such as the rules of bulge deformation. Moreover, the three-dimensional model has been compared with a two-dimensional model to discuss the differences between the two models in calculating the bulge deformation. The results show that the platform zone exists in the wide side of the slab and the bulge deformation is affected strongly by the ratio of width-to-thickness. The indications are also that the difference of the bulge deformation for the two modeling ways is little when the ratio of width-to-thickness is larger than six.

  17. Thermodynamic modeling of the power plant based on the SOFC with internal steam reforming of methane

    International Nuclear Information System (INIS)

    Ivanov, Peter

    2007-01-01

    Mathematical model based on the thermodynamic modeling of gaseous mixtures is developed for SOFC with internal steam reforming of methane. Macroscopic porous-electrode theory, including non-linear kinetics and gas-phase diffusion, is used to calculate the reforming reaction and the concentration polarization. Provided the data concerning properties and costs of materials the model is fit for wide range of parametric analysis of thermodynamic cycles including SOFC

  18. Thermodynamic activity-based intrinsic enzyme kinetic sheds light on enzyme-solvent interactions.

    Science.gov (United States)

    Grosch, Jan-Hendrik; Wagner, David; Nistelkas, Vasilios; Spieß, Antje C

    2017-01-01

    The reaction medium has major impact on biocatalytic reaction systems and on their economic significance. To allow for tailored medium engineering, thermodynamic phenomena, intrinsic enzyme kinetics, and enzyme-solvent interactions have to be discriminated. To this end, enzyme reaction kinetic modeling was coupled with thermodynamic calculations based on investigations of the alcohol dehydrogenase from Lactobacillus brevis (LbADH) in monophasic water/methyl tert-butyl ether (MTBE) mixtures as a model solvent. Substrate concentrations and substrate thermodynamic activities were varied separately to identify the individual thermodynamic and kinetic effects on the enzyme activity. Microkinetic parameters based on concentration and thermodynamic activity were derived to successfully identify a positive effect of MTBE on the availability of the substrate to the enzyme, but a negative effect on the enzyme performance. In conclusion, thermodynamic activity-based kinetic modeling might be a suitable tool to initially curtail the type of enzyme-solvent interactions and thus, a powerful first step to potentially understand the phenomena that occur in nonconventional media in more detail. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:96-103, 2017. © 2016 American Institute of Chemical Engineers.

  19. Comparison of Ablation Predictions for Carbonaceous Materials Using CEA and JANAF-Based Species Thermodynamics

    Science.gov (United States)

    Milos, Frank S.

    2011-01-01

    In most previous work at NASA Ames Research Center, ablation predictions for carbonaceous materials were obtained using a species thermodynamics database developed by Aerotherm Corporation. This database is derived mostly from the JANAF thermochemical tables. However, the CEA thermodynamics database, also used by NASA, is considered more up to date. In this work, the FIAT code was modified to use CEA-based curve fits for species thermodynamics, then analyses using both the JANAF and CEA thermodynamics were performed for carbon and carbon phenolic materials over a range of test conditions. The ablation predictions are comparable at lower heat fluxes where the dominant mechanism is carbon oxidation. However, the predictions begin to diverge in the sublimation regime, with the CEA model predicting lower recession. The disagreement is more significant for carbon phenolic than for carbon, and this difference is attributed to hydrocarbon species that may contribute to the ablation rate.

  20. Does the Galactic Bulge Have Fewer Planets?

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    The Milky Ways dense central bulge is a very different environment than the surrounding galactic disk in which we live. Do the differences affect the ability of planets to form in the bulge?Exploring Galactic PlanetsSchematic illustrating how gravitational microlensing by an extrasolar planet works. [NASA]Planet formation is a complex process with many aspects that we dont yet understand. Do environmental properties like host star metallicity, the density of nearby stars, or the intensity of the ambient radiation field affect the ability of planets to form? To answer these questions, we will ultimately need to search for planets around stars in a large variety of different environments in our galaxy.One way to detect recently formed, distant planets is by gravitational microlensing. In this process, light from a distant source star is bent by a lens star that is briefly located between us and the source. As the Earth moves, this momentary alignment causes a blip in the sources light curve that we can detect and planets hosted by the lens star can cause an additional observable bump.Artists impression of the Milky Way galaxy. The central bulge is much denserthan the surroundingdisk. [ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt]Relative AbundancesMost source stars reside in the galactic bulge, so microlensing events can probe planetary systems at any distance between the Earth and the galactic bulge. This means that planet detections from microlensing could potentially be used to measure the relative abundances of exoplanets in different parts of our galaxy.A team of scientists led by Matthew Penny, a Sagan postdoctoral fellow at Ohio State University, set out to do just that. The group considered a sample of 31 exoplanetary systems detected by microlensing and asked the following question: are the planet abundances in the galactic bulge and the galactic disk the same?A Paucity of PlanetsTo answer this question, Penny and collaborators derived the expected

  1. a Study of the AGB in Local Group Bulge Populations

    Science.gov (United States)

    Rich, R.

    1994-01-01

    We propose to survey the bolometric luminosities, colors, and space distribution of the most luminous asymptotic giant branch (AGB) stars in the bulges of M31, M32, and M33. We seek to discover whether the bulges of these galaxies are relatively young, of order 10 Gyr rather than 15 Gyr. We will use WFPC2 and the R, I, and F1042M (1 micron) filters. Knowing that F1042M falls on the first continuum point of M giants, we have shown that we can use 1.04 micron fluxes to reliably calculate bolometric magnitudes for these very red stars. Color information from R and I will permit (1) comparison with Galactic bulge M giants, (2) an estimate of the spread of abundance and (3) increase the accuracy of the bolometric magnitudes. Frames with the damaged HST show signs of resolution to within 3" of the M31 nucleus; Red images with the aberrated HST show a red star cluster associated with the nucleus. Ground-based studies of M32 find an intermediate-age population from spectroscopy and infrared photometry. The repaired HST should resolve stars close to the nuclei of these galaxies. We will measure bolometric luminosity functions to determine if the populations are intermediate age, and attempt to measure the abundance range for stars near the nuclei of these galaxies. If metals have been lost due to winds, theory predicts that we should see a substantial spread of abundances even near the nucleus.

  2. Are there carbon stars in the Bulge ?

    OpenAIRE

    Ng, Y. K.

    1998-01-01

    The bulge carbon stars have been a mystery since their discovery, because they are about 2.5mag too faint to be regarded as genuine AGB stars, if located inside the metal-rich bulge (m-M=14.5mag). Part of the mystery can be solved if these carbon stars are related to the Sagittarius dwarf galaxy (SDG; m-M=17.0mag). They are in that case not old and metal-rich, but young, ~0.1 Gyr, with SMC-like metallicity. The sigma_RV=113+/-14 km/s radial velocity dispersion of the stars appears to be consi...

  3. Applications of thermodynamic calculations to Mg alloy design: Mg-Sn based alloy development

    International Nuclear Information System (INIS)

    Jung, In-Ho; Park, Woo-Jin; Ahn, Sang Ho; Kang, Dae Hoon; Kim, Nack J.

    2007-01-01

    Recently an Mg-Sn based alloy system has been investigated actively in order to develop new magnesium alloys which have a stable structure and good mechanical properties at high temperatures. Thermodynamic modeling of the Mg-Al-Mn-Sb-Si-Sn-Zn system was performed based on available thermodynamic, phase equilibria and phase diagram data. Using the optimized database, the phase relationships of the Mg-Sn-Al-Zn alloys with additions of Si and Sb were calculated and compared with their experimental microstructures. It is shown that the calculated results are in good agreement with experimental microstructures, which proves the applicability of thermodynamic calculations for new Mg alloy design. All calculations were performed using FactSage thermochemical software. (orig.)

  4. Bulge growth and quenching since z = 2.5 in CANDELS/3D-HST

    International Nuclear Information System (INIS)

    Lang, Philipp; Wuyts, Stijn; Schreiber, Natascha M. Förster; Genzel, Reinhard; Lutz, Dieter; Rosario, David J.; Somerville, Rachel S.; Bell, Eric F.; Brammer, Gabe; Dekel, Avishai; Faber, Sandra M.; Momcheva, Ivelina; Ferguson, Henry C.; Grogin, Norman A.; Koekemoer, Anton M.; Kocevski, Dale D.; McGrath, Elizabeth J.; Nelson, Erica J.; Primack, Joel R.; Skelton, Rosalind E.

    2014-01-01

    Exploiting the deep high-resolution imaging of all five CANDELS fields, and accurate redshift information provided by 3D-HST, we investigate the relation between structure and stellar populations for a mass-selected sample of 6764 galaxies above 10 10 M ☉ , spanning the redshift range 0.5 < z < 2.5. For the first time, we fit two-dimensional models comprising a single Sérsic fit and two-component (i.e., bulge + disk) decompositions not only to the H-band light distributions, but also to the stellar mass maps reconstructed from resolved stellar population modeling. We confirm that the increased bulge prominence among quiescent galaxies, as reported previously based on rest-optical observations, remains in place when considering the distributions of stellar mass. Moreover, we observe an increase of the typical Sérsic index and bulge-to-total ratio (with median B/T reaching 40%-50%) among star-forming galaxies above 10 11 M ☉ . Given that quenching for these most massive systems is likely to be imminent, our findings suggest that significant bulge growth precedes a departure from the star-forming main sequence. We demonstrate that the bulge mass (and ideally knowledge of the bulge and total mass) is a more reliable predictor of the star-forming versus quiescent state of a galaxy than the total stellar mass. The same trends are predicted by the state-of-the-art, semi-analytic model by Somerville et al. In this model, bulges and black holes grow hand in hand through merging and/or disk instabilities, and feedback from active galactic nuclei shuts off star formation. Further observations will be required to pin down star formation quenching mechanisms, but our results imply that they must be internal to the galaxies and closely associated with bulge growth.

  5. Gauging the Helium Abundance of the Galactic Bulge RR Lyrae Stars

    Science.gov (United States)

    Marconi, Marcella; Minniti, Dante

    2018-02-01

    We report the first estimate of the He abundance of the population of RR Lyrae stars in the Galactic bulge. This is done by comparing the recent observational data with the latest models. We use the large samples of ab-type RR Lyrae stars found by OGLE IV in the inner bulge and by the VVV survey in the outer bulge. We present the result from the new models computed by Marconi et al., showing that the minimum period for fundamental RR Lyrae pulsators depends on the He content. By comparing these models with the observations in a period versus effective temperature plane, we find that the bulk of the bulge ab-type RR Lyrae are consistent with primordial He abundance Y = 0.245, ruling out a significant He-enriched population. This work demonstrates that the He content of the bulge RR Lyrae is different from that of the bulk of the bulge population as traced by the red clump giants that appear to be significantly more He-rich. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 179.B-2002 and 298.D-5048.

  6. Thermodynamic analysis of an HCCI engine based system running on natural gas

    International Nuclear Information System (INIS)

    Djermouni, Mohamed; Ouadha, Ahmed

    2014-01-01

    Highlights: • A thermodynamic analysis of an HCCI based system has been carried out. • A thermodynamic model has been developed taking into account the gas composition resulting from the combustion process. • The specific heat of the working fluid is temperature dependent. - Abstract: This paper attempts to carry out a thermodynamic analysis of a system composed of a turbocharged HCCI engine, a mixer, a regenerator and a catalytic converter within the meaning of the first and the second law of thermodynamics. For this purpose, a thermodynamic model has been developed taking into account the gas composition resulting from the combustion process and the specific heat temperature dependency of the working fluid. The analysis aims in particular to examine the influence of the compressor pressure ratio, ambient temperature, equivalence ratio, engine speed and the compressor isentropic efficiency on the performance of the HCCI engine. Results show that thermal and exergetic efficiencies increase with increasing the compressor pressure ratio. However, the increase of the ambient temperature involves a decrease of the engine efficiencies. Furthermore, the variation of the equivalence ratio improves considerably both thermal and exergetic efficiencies. As expected, the increase of the engine speed enhances the engine performances. Finally, an exergy losses mapping of the system show that the maximum exergy losses occurs in the HCCI engine

  7. Manganese abundances in Galactic bulge red giants

    Science.gov (United States)

    Barbuy, B.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.; Trevisan, M.; Dutra, N.

    2013-11-01

    Context. Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut between the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. Aims: The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. Methods: High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. Results: We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Galactic bulge. We find [Mn/Fe] ~ -0.7 at [Fe/H] ~ -1.3, increasing to a solar value at metallicities close to solar, and showing a spread around - 0.7 ≲ [Fe/H] ≲ -0.2, in good agreement with other work on Mn in bulge stars. There is also good agreement with chemical evolution models. We find no clear difference in the behaviour of the four bulge fields. Whereas [Mn/Fe] vs. [Fe/H] could be identified with the behaviour of the thick disc stars, [Mn/O] vs. [O/H] has a behaviour running parallel, at higher metallicities, compared to thick disc stars, indicating that the bulge enrichment might have proceeded differently from that of the thick disc. Observations collected at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Tables 1-6 and Figs. 1-6 are available in electronic form at http://www.aanda.org

  8. Improving Students' Chemical Literacy Levels on Thermochemical and Thermodynamics Concepts through a Context-Based Approach

    Science.gov (United States)

    Cigdemoglu, Ceyhan; Geban, Omer

    2015-01-01

    The aim of this study was to delve into the effect of context-based approach (CBA) over traditional instruction (TI) on students' chemical literacy level related to thermochemical and thermodynamics concepts. Four eleventh-grade classes with 118 students in total taught by two teachers from a public high school in 2012 fall semester were enrolled…

  9. Thermodynamically based solvent design for enzymatic saccharide acylation with hydroxycinnamic acids in non-conventional media

    DEFF Research Database (Denmark)

    Zeuner, Birgitte; Kontogeorgis, Georgios; Riisager, Anders

    2012-01-01

    as a crucial part of the reaction design, the review explores the use of activity coefficient models for describing these systems and – more importantly – the use of group contribution model UNIFAC and quantum chemistry based COSMO-RS for thermodynamic predictions and preliminary solvent screening. Surfactant...

  10. Thermodynamic properties and atomic structure of Ca-based liquid alloys

    Science.gov (United States)

    Poizeau, Sophie

    To identify the most promising positive electrodes for Ca-based liquid metal batteries, the thermodynamic properties of diverse Ca-based liquid alloys were investigated. The thermodynamic properties of Ca-Sb alloys were determined by emf measurements. It was found that Sb as positive electrode would provide the highest voltage for Ca-based liquid metal batteries (1 V). The price of such a battery would be competitive for the grid-scale energy storage market. The impact of Pb, a natural impurity of Sb, was predicted successfully and confirmed via electrochemical measurements. It was shown that the impact on the open circuit voltage would be minor. Indeed, the interaction between Ca and Sb was demonstrated to be much stronger than between Ca and Pb using thermodynamic modeling, which explains why the partial thermodynamic properties of Ca would not vary much with the addition of Pb to Sb. However, the usage of the positive electrode would be reduced, which would limit the interest of a Pb-Sb positive electrode. Throughout this work, the molecular interaction volume model (MIVM) was used for the first time for alloys with thermodynamic properties showing strong negative deviation from ideality. This model showed that systems such as Ca-Sb have strong short-range order: Ca is most stable when its first nearest neighbors are Sb. This is consistent with what the more traditional thermodynamic model, the regular association model, would predict. The advantages of the MIVM are the absence of assumption regarding the composition of an associate, and the reduced number of fitting parameters (2 instead of 5). Based on the parameters derived from the thermodynamic modeling using the MIVM, a new potential of mixing for liquid alloys was defined to compare the strength of interaction in different Ca-based alloys. Comparing this trend with the strength of interaction in the solid state of these systems (assessed by the energy of formation of the intermetallics), the systems with

  11. The intrinsic shape of bulges in the CALIFA survey

    Science.gov (United States)

    Costantin, L.; Méndez-Abreu, J.; Corsini, E. M.; Eliche-Moral, M. C.; Tapia, T.; Morelli, L.; Dalla Bontà, E.; Pizzella, A.

    2018-02-01

    Context. The intrinsic shape of galactic bulges in nearby galaxies provides crucial information to separate bulge types. Aims: We aim to derive accurate constraints to the intrinsic shape of bulges to provide new clues on their formation mechanisms and set new limitations for future simulations. Methods: We retrieved the intrinsic shape of a sample of CALIFA bulges using a statistical approach. Taking advantage of GalMer numerical simulations of binary mergers we estimated the reliability of the procedure. Analyzing the i-band mock images of resulting lenticular remnants, we studied the intrinsic shape of their bulges at different galaxy inclinations. Finally, we introduced a new (B/A, C/A) diagram to analyze possible correlations between the intrinsic shape and the properties of bulges. Results: We tested the method on simulated lenticular remnants, finding that for galaxies with inclinations of 25° ≤ θ ≤ 65° we can safely derive the intrinsic shape of their bulges. We found that our CALIFA bulges tend to be nearly oblate systems (66%), with a smaller fraction of prolate spheroids (19%), and triaxial ellipsoids (15%). The majority of triaxial bulges are in barred galaxies (75%). Moreover, we found that bulges with low Sérsic indices or in galaxies with low bulge-to-total luminosity ratios form a heterogeneous class of objects; additionally, bulges in late-type galaxies or in less massive galaxies have no preference for being oblate, prolate, or triaxial. On the contrary, bulges with high Sérsic index, in early-type galaxies, or in more massive galaxies are mostly oblate systems. Conclusions: We concluded that various evolutionary pathways may coexist in galaxies, with merging events and dissipative collapse being the main mechanisms driving the formation of the most massive oblate bulges and bar evolution reshaping the less massive triaxial bulges.

  12. Establishment of data base files of thermodynamic data developed by OECD/NEA. Pt. 2. Thermodynamic data of Tc, U, Np, Pu and Am with auxiliary species

    International Nuclear Information System (INIS)

    Yoshida, Yasushi; Shibata, Masahiro

    2005-03-01

    Thermodynamic data base for compounds and complexes of actinides and fission products with auxiliary species specialized in modeling requirements for safety assessment of radioactive waste disposal systems are being developed by NEA TDB project of OECD/NEA. In this project, relevant data bases for compounds and complexes of U, Am, Tc, Np and Pu with auxiliary species were updated and published in 2003. JNC established the data base files available for geochemical calculation codes using these updated data. The procedure for establishment and contents of data base files are described in this report. These data base files were prepared as the formats of major geochemical codes PHREEQE, PHREEQC, EQ3/6 and Geochemist's workbench. Additionally modification for data in the thermodynamic data base files which had been already published by JNC was also done. This procedure and revised data bases are shown in the appendix of this report. (author)

  13. EXPLORING THE UNUSUALLY HIGH BLACK-HOLE-TO-BULGE MASS RATIOS IN NGC 4342 AND NGC 4291: THE ASYNCHRONOUS GROWTH OF BULGES AND BLACK HOLES

    International Nuclear Information System (INIS)

    Bogdán, Ákos; Forman, William R.; Kraft, Ralph P.; Li, Zhiyuan; Vikhlinin, Alexey; Nulsen, Paul E. J.; Jones, Christine; Zhuravleva, Irina; Churazov, Eugene; Mihos, J. Christopher; Harding, Paul; Guo, Qi; Schindler, Sabine

    2012-01-01

    We study two nearby early-type galaxies, NGC 4342 and NGC 4291, that host unusually massive black holes relative to their low stellar mass. The observed black-hole-to-bulge mass ratios of NGC 4342 and NGC 4291 are 6.9 +3.8 –2.3 % and 1.9% ± 0.6%, respectively, which significantly exceed the typical observed ratio of ∼0.2%. As a consequence of the exceedingly large black-hole-to-bulge mass ratios, NGC 4342 and NGC 4291 are ≈5.1σ and ≈3.4σ outliers from the M . -M bulge scaling relation, respectively. In this paper, we explore the origin of the unusually high black-hole-to-bulge mass ratio. Based on Chandra X-ray observations of the hot gas content of NGC 4342 and NGC 4291, we compute gravitating mass profiles, and conclude that both galaxies reside in massive dark matter halos, which extend well beyond the stellar light. The presence of dark matter halos around NGC 4342 and NGC 4291 and a deep optical image of the environment of NGC 4342 indicate that tidal stripping, in which ∼> 90% of the stellar mass was lost, cannot explain the observed high black-hole-to-bulge mass ratios. Therefore, we conclude that these galaxies formed with low stellar masses, implying that the bulge and black hole did not grow in tandem. We also find that the black hole mass correlates well with the properties of the dark matter halo, suggesting that dark matter halos may play a major role in regulating the growth of the supermassive black holes.

  14. An Application of Context- and Problem-Based Learning (C-PBL) into Teaching Thermodynamics

    Science.gov (United States)

    Baran, Mukadder; Sozbilir, Mustafa

    2017-05-01

    This study aims to investigate the applicability of context- and problem-based learning (C-PBL) into teaching thermodynamics and to examine its influence on the students' achievements in chemistry, retention of knowledge, students' attitudes, motivation and interest towards chemistry. The embedded mixed method design was utilized with a group of 13 chemistry students in a 2-year program of "Medical Laboratory and Techniques" at a state university in an underdeveloped city at the southeastern region of Turkey. The research data were collected via questionnaires regarding the students' attitudes, motivation and interest in chemistry, an achievement test on "thermodynamics" and interviews utilized to find out the applicability of C-PBL into thermodynamics. The findings demonstrated that C-PBL led a statistically significant increase in the students' achievement in thermodynamics and their interest in chemistry, while no statistically significant difference was observed in the students' attitudes and motivation towards chemistry before and after the intervention. The interviews revealed that C-PBL developed not only the students' communication skills but also their skills in using time effectively, making presentations, reporting research results and using technology. It was also found to increase their self-confidence together with the positive attitudes towards C-PBL and being able to associate chemistry with daily life. In light of these findings, it could be stated that it will be beneficial to increase the use of C-PBL in teaching chemistry.

  15. A review of marine anthropogenic CO2 definitions: introducing a thermodynamic approach based on observations

    International Nuclear Information System (INIS)

    Friis, Karsten

    2006-01-01

    A review of existing methods that define anthropogenic CO 2 as deduced from total inorganic carbon is presented. A refined approach to define anthropogenic CO 2 is introduced that has a stronger thermodynamic orientation than current methods, and is based on a back-calculation technique by Chen and Millero and Poisson and Chen. Anthropogenic CO 2 results of the new technique are compared with results from the original technique as well as with results of the technique of Gruber et al. The new technique is furthermore applied to three time-separated data sets in the subpolar North Atlantic and shows consistent results with regard to available data quality and anthropogenic CO 2 quantities. The difference between the new thermodynamic approach and the anthropogenic CO 2 definition of Gruber et al., which is termed mechanistic, is discussed. Here likely changes in the CO 2 solubility pump are a thermodynamic property of this definition, whereas it is a separate phenomenon in the mechanistic definition. The thermodynamic approach is not without caveats, but points to improvements by the synergistic use of model results and those from observations. Future improvements are considered for the initial saturation state of oxygen and CO 2 , at the instant the surface water loses contact with the atmosphere and for variations in the Redfield ratio

  16. Insights on the Milky Way bulge formation from the correlations between kinematics and metallicity

    Science.gov (United States)

    Babusiaux, C.; Gómez, A.; Hill, V.; Royer, F.; Zoccali, M.; Arenou, F.; Fux, R.; Lecureur, A.; Schultheis, M.; Barbuy, B.; Minniti, D.; Ortolani, S.

    2010-09-01

    Context. Two main scenarios for the formation of the Galactic bulge are invoked, the first one through gravitational collapse or hierarchical merging of subclumps, the second through secular evolution of the Galactic disc. Aims: We aim to constrain the formation of the Galactic bulge through studies of the correlation between kinematics and metallicities in Baade's Window (l = 1°, b = -4°) and two other fields along the bulge minor axis (l = 0°, b = -6° and b = -12°). Methods: We combine the radial velocity and the [Fe/H] measurements obtained with FLAMES/GIRAFFE at the VLT with a spectral resolution of R = 20 000, plus for the Baade's Window field the OGLE-II proper motions, and compare these with published N-body simulations of the Galactic bulge. Results: We confirm the presence of two distinct populations in Baade's Window found in Hill et al. (2010, A&A, submitted): the metal-rich population presents bar-like kinematics while the metal-poor population shows kinematics corresponding to an old spheroid or a thick disc. In this context the metallicity gradient along the bulge minor axis observed by Zoccali et al. (2008, A&A, 486, 177), visible also in the kinematics, can be related to a varying mix of these two populations as one moves away from the Galactic plane, alleviating the apparent contradiction between the kinematic evidence of a bar and the existence of a metallicity gradient. Conclusions: We show evidence that the two main scenarios for the bulge formation co-exist within the Milky Way bulge. Based on ESO-VLT observations 71.B-0617, 73.B-0074, and Paris Observatory GTO 71.B-0196.

  17. Explaining the Formation of Bulges with MOND

    Science.gov (United States)

    Combes, Françoise

    In the cold dark matter (CDM) paradigm, bulges easily form through galaxy mergers, either major or minor, or through clumpy discs in the early universe, where clumps are driven to the center by dynamical friction. Also pseudobulges, with a more discy morphology and kinematics, can form more slowly through secular evolution of a bar, where resonant stars are elevated out of the plane, in a peanut/box shape. As a result, in CDM cosmological simulations, it is very difficult to find a bulgeless galaxy, while they are observed very frequently in the local universe. A different picture emerges in alternative models of the missing mass problem. In MOND (MOdified Newtonian Dynamics), galaxy mergers are much less frequent, since the absence of dark matter halos reduces the dynamical friction between two galaxies. Also, while clumpy galaxies lead to rapid classical bulge formation in CDM, the inefficient dynamical friction with MOND in the early-universe galaxies prevents the clumps to coalesce together in the center to form spheroids. This leads to less frequent and less massive classical bulges. Bars in MOND are more frequent and stronger, and have a more constant pattern speed, which modifies significantly the pseudobulge morphology. The fraction of pseudobulges is expected to be dominant in MOND.

  18. THEREDA. Thermodynamic reference data base. Phase II. Release of thermodynamic data. Summary and final report; THEREDA. Thermodynamische Referenz-Datenbasis. Phase II. Freigabe thermodynamischer Daten. Zusammenfassung der Abschlussberichte

    Energy Technology Data Exchange (ETDEWEB)

    Altmaier, Marcus; Gaona, Xavier; Marquardt, Christian; Montoya, Vanessa [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Institut fuer Nukleare Entsorgung; Bok, Frank; Richter, Anke [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Moog, Helge C.; Scharge, Tina [Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (GRS), Koeln (Germany); Voigt, Wolfgang [Technische Univ. Bergakademie Freiberg (Germany); Wilhelm, Stefan [AF Consult AG, Baden-Daettwil (Switzerland)

    2015-12-15

    The final report on the thermodynamic reference data base THEREDA covers the following issues: project management, quality management (Helmholtz-Zentrum Dresden-Rossendorf HZDR and GRS), data base interfaces, documentation, uranium (HZDR), other nuclides (Karlsruhe Institute for technology, KIT), data for cement minerals and their reaction products (AF-Consult, GRS), phosphate (GRS), systems with CO2 and carbonate at variable temperatures and pressure (Bergakademie Freiberg, TUBAF).

  19. The metallicity distribution of bulge clump giants in Baade's window

    Science.gov (United States)

    Hill, V.; Lecureur, A.; Gómez, A.; Zoccali, M.; Schultheis, M.; Babusiaux, C.; Royer, F.; Barbuy, B.; Arenou, F.; Minniti, D.; Ortolani, S.

    2011-10-01

    ) and for the metal-rich component, a formation on a longer time scale driven by the evolution of the bar (pseudo-bulge). The observations are described well by a simple model consisting of two components: a simple closed box model to predict the metal-poor population contribution and a local thin disc metallicity distribution, shifted in metallicity, to represent the metal-rich population. The pseudo-bulge is compatible with its being formed from the inner thin disc, assuming high (but plausible) values of the gradients in the early Galactic disc. Based on ESO-VLT observations during Paris Observatory FLAMES GTO 71.B-0196.Full Tables 1-3 are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A80

  20. ARGOS - IV. The kinematics of the Milky Way bulge

    Science.gov (United States)

    Ness, M.; Freeman, K.; Athanassoula, E.; Wylie-de-Boer, E.; Bland-Hawthorn, J.; Asplund, M.; Lewis, G. F.; Yong, D.; Lane, R. R.; Kiss, L. L.; Ibata, R.

    2013-07-01

    We present the kinematic results from our ARGOS spectroscopic survey of the Galactic bulge of the Milky Way. Our aim is to understand the formation of the Galactic bulge. We examine the kinematics of about 17 400 stars in the bulge located within 3.5 kpc of the Galactic Centre, identified from the 28 000 star ARGOS survey. We aim to determine if the formation of the bulge has been internally driven from disc instabilities as suggested by its boxy shape, or if mergers have played a significant role as expected from lambda cold dark matter simulations. From our velocity measurements across latitudes b = -5°, - 7.5° and -10° we find the bulge to be a cylindrically rotating system that transitions smoothly out into the disc. From observations of 3 fields at b = +10, the kinematics of the bulge show North-South symmetry about the major axis. Within the bulge, we find a kinematically distinct metal-poor population ([Fe/H] ARGOS Paper III (mean [Fe/H] ≈ -0.25 and [Fe/H] ≈ +0.15, respectively) demonstrate that they are likely to share a common formation origin and are distinct from the more metal-poor populations of the thick disc and halo which are co-located inside the bulge. We do not exclude an underlying merger generated bulge component but our results favour bulge formation from instabilities in the early thin disc.

  1. Thermodynamics of information processing based on enzyme kinetics: An exactly solvable model of an information pump

    Science.gov (United States)

    Cao, Yuansheng; Gong, Zongping; Quan, H. T.

    2015-06-01

    Motivated by the recent proposed models of the information engine [Proc. Natl. Acad. Sci. USA 109, 11641 (2012), 10.1073/pnas.1204263109] and the information refrigerator [Phys. Rev. Lett. 111, 030602 (2013), 10.1103/PhysRevLett.111.030602], we propose a minimal model of the information pump and the information eraser based on enzyme kinetics. This device can either pump molecules against the chemical potential gradient by consuming the information to be encoded in the bit stream or (partially) erase the information initially encoded in the bit stream by consuming the Gibbs free energy. The dynamics of this model is solved exactly, and the "phase diagram" of the operation regimes is determined. The efficiency and the power of the information machine is analyzed. The validity of the second law of thermodynamics within our model is clarified. Our model offers a simple paradigm for the investigating of the thermodynamics of information processing involving the chemical potential in small systems.

  2. Dynamics of contact line depinning during droplet evaporation based on thermodynamics.

    Science.gov (United States)

    Yu, Dong In; Kwak, Ho Jae; Doh, Seung Woo; Ahn, Ho Seon; Park, Hyun Sun; Kiyofumi, Moriyama; Kim, Moo Hwan

    2015-02-17

    For several decades, evaporation phenomena have been intensively investigated for a broad range of applications. However, the dynamics of contact line depinning during droplet evaporation has only been inductively inferred on the basis of experimental data and remains unclear. This study focuses on the dynamics of contact line depinning during droplet evaporation based on thermodynamics. Considering the decrease in the Gibbs free energy of a system with different evaporation modes, a theoretical model was developed to estimate the receding contact angle during contact line depinning as a function of surface conditions. Comparison of experimentally measured and theoretically modeled receding contact angles indicated that the dynamics of contact line depinning during droplet evaporation was caused by the most favorable thermodynamic process encountered during constant contact radius (CCR mode) and constant contact angle (CCA mode) evaporation to rapidly reach an equilibrium state during droplet evaporation.

  3. Statistical thermodynamics

    International Nuclear Information System (INIS)

    Hwang, Jeong Ui; Jang, Jong Jae; Jee, Jong Gi

    1987-01-01

    The contents of this book are thermodynamics on the law of thermodynamics, classical thermodynamics and molecule thermodynamics, basics of molecule thermodynamics, molecule and assembly partition function, molecule partition function, classical molecule partition function, thermodynamics function for ideal assembly in fixed system, thermodynamics function for ideal assembly in running system, Maxwell-Boltzmann's law of distribution, chemical equilibrium like calculation of equilibrium constant and theory of absolute reaction rate.

  4. Mixture model-based atmospheric air mass classification: a probabilistic view of thermodynamic profiles

    Science.gov (United States)

    Pernin, Jérôme; Vrac, Mathieu; Crevoisier, Cyril; Chédin, Alain

    2017-04-01

    Air mass classification has become an important area in synoptic climatology, simplifying the complexity of the atmosphere by dividing the atmosphere into discrete similar thermodynamic patterns. However, the constant growth of atmospheric databases in both size and complexity implies the need to develop new adaptive classifications. Here, we propose a robust unsupervised and supervised classification methodology of a large thermodynamic dataset, on a global scale and over several years, into discrete air mass groups homogeneous in both temperature and humidity that also provides underlying probability laws. Temperature and humidity at different pressure levels are aggregated into a set of cumulative distribution function (CDF) values instead of classical ones. The method is based on a Gaussian mixture model and uses the expectation-maximization (EM) algorithm to estimate the parameters of the mixture. Spatially gridded thermodynamic profiles come from ECMWF reanalyses spanning the period 2000-2009. Different aspects are investigated, such as the sensitivity of the classification process to both temporal and spatial samplings of the training dataset. Comparisons of the classifications made either by the EM algorithm or by the widely used k-means algorithm show that the former can be viewed as a generalization of the latter. Moreover, the EM algorithm delivers, for each observation, the probabilities of belonging to each class, as well as the associated uncertainty. Finally, a decision tree is proposed as a tool for interpreting the different classes, highlighting the relative importance of temperature and humidity in the classification process.

  5. Investigation of the Thermodynamic Process of the Refrigerator Compressor Based on the m-θ Diagram

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2017-10-01

    Full Text Available The variation of refrigerant mass in the cylinder of refrigerator compressor has a great influence on the compressor’s thermodynamic process. In this paper, the m-θ diagram, which represents the variation of refrigerant mass in compressor cylinder (m and the crank angle (θ, is proposed to investigate the thermodynamic process of the refrigerator compressor. Comparing with the traditional pressure-Volume (p-V indicator diagram, the refrigerant’s backflow trigged by the delayed closure of valve can be clearly expressed in the m-θ diagram together with the mass flow rate. A typical m-θ diagram was obtained by experimental and theoretical investigations. To improve the thermodynamic model of the compressor, a 3D fluid-structure interaction (FSI FEA model has been introduced to find out the effective flow area of the valves. Based on the m-θ diagram, the effect of rotating speed on the backflow through the valve, which depends on the movement of the valve, has been investigated. Specific to the compressor used in this study, the maximum backflow through the suction valve and discharge valve occur at 3500 r·min−1 and 5500 r·min−1, respectively.

  6. Estimation model for evaporative emissions from gasoline vehicles based on thermodynamics.

    Science.gov (United States)

    Hata, Hiroo; Yamada, Hiroyuki; Kokuryo, Kazuo; Okada, Megumi; Funakubo, Chikage; Tonokura, Kenichi

    2018-03-15

    In this study, we conducted seven-day diurnal breathing loss (DBL) tests on gasoline vehicles. We propose a model based on the theory of thermodynamics that can represent the experimental results of the current and previous studies. The experiments were performed using 14 physical parameters to determine the dependence of total emissions on temperature, fuel tank fill, and fuel vapor pressure. In most cases, total emissions after an apparent breakthrough were proportional to the difference between minimum and maximum environmental temperatures during the day, fuel tank empty space, and fuel vapor pressure. Volatile organic compounds (VOCs) were measured using a Gas Chromatography Mass Spectrometer and Flame Ionization Detector (GC-MS/FID) to determine the Ozone Formation Potential (OFP) of after-breakthrough gas emitted to the atmosphere. Using the experimental results, we constructed a thermodynamic model for estimating the amount of evaporative emissions after a fully saturated canister breakthrough occurred, and a comparison between the thermodynamic model and previous models was made. Finally, the total annual evaporative emissions and OFP in Japan were determined and compared by each model. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Constraints of Compound Systems: Prerequisites for Thermodynamic Modeling Based on Shannon Entropy

    Directory of Open Access Journals (Sweden)

    Martin Pfleger

    2014-05-01

    Full Text Available Thermodynamic modeling of extensive systems usually implicitly assumes the additivity of entropy. Furthermore, if this modeling is based on the concept of Shannon entropy, additivity of the latter function must also be guaranteed. In this case, the constituents of a thermodynamic system are treated as subsystems of a compound system, and the Shannon entropy of the compound system must be subjected to constrained maximization. The scope of this paper is to clarify prerequisites for applying the concept of Shannon entropy and the maximum entropy principle to thermodynamic modeling of extensive systems. This is accomplished by investigating how the constraints of the compound system have to depend on mean values of the subsystems in order to ensure additivity. Two examples illustrate the basic ideas behind this approach, comprising the ideal gas model and condensed phase lattice systems as limiting cases of fluid phases. The paper is the first step towards developing a new approach for modeling interacting systems using the concept of Shannon entropy.

  8. Thermodynamic Spectrum of Solar Flares Based on SDO/EVE Observations: Techniques and First Results

    Science.gov (United States)

    Wang, Yuming; Zhou, Zhenjun; Zhang, Jie; Liu, Kai; Liu, Rui; Shen, Chenglong; Chamberlin, Phillip C.

    2016-01-01

    The Solar Dynamics Observatory (SDO)/EUV Variability Experiment (EVE) provides rich information on the thermodynamic processes of solar activities, particularly on solar flares. Here, we develop a method to construct thermodynamic spectrum (TDS) charts based on the EVE spectral lines. This tool could potentially be useful for extreme ultraviolet (EUV) astronomy to learn about the eruptive activities on distant astronomical objects. Through several cases, we illustrate what we can learn from the TDS charts. Furthermore, we apply the TDS method to 74 flares equal to or greater than the M5.0 class, and reach the following statistical results. First, EUV peaks are always behind the soft X-ray (SXR) peaks and stronger flares tend to have faster cooling rates. There is a power-law correlation between the peak delay times and the cooling rates, suggesting a coherent cooling process of flares from SXR to EUV emissions. Second, there are two distinct temperature drift patterns, called Type I and Type II. For Type I flares, the enhanced emission drifts from high to low temperature like a quadrilateral, whereas for Type II flares the drift pattern looks like a triangle. Statistical analysis suggests that Type II flares are more impulsive than Type I flares. Third, for late-phase flares, the peak intensity ratio of the late phase to the main phase is roughly correlated with the flare class, and the flares with a strong late phase are all confined. We believe that the re-deposition of the energy carried by a flux rope, which unsuccessfully erupts out, into thermal emissions is responsible for the strong late phase found in a confined flare. Furthermore, we show the signatures of the flare thermodynamic process in the chromosphere and transition region in the TDS charts. These results provide new clues to advance our understanding of the thermodynamic processes of solar flares and associated solar eruptions, e.g., coronal mass ejections.

  9. Stochastic thermodynamics

    Science.gov (United States)

    Eichhorn, Ralf; Aurell, Erik

    2014-04-01

    'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response

  10. The development of platinum-based alloys and their thermodynamic database

    OpenAIRE

    Cornish L.A.; Hohls J.; Hill P.J.; Prins S.; Süss R.; Compton D.N.

    2002-01-01

    A series of quaternary platinum-based alloys have been demonstrated to exhibit the same two-phase structure as Ni-based superalloys and showed good mechanical properties. The properties of ternary alloys were a good indication that the quaternary alloys, with their better microstructure, will be even better. The quaternary alloy composition has been optimised at Pt84:Al11:Ru2:Cr3 for the best microstructure and hardness. Work has begun on establishing a thermodynamic database for Pt-Al-Ru-Cr ...

  11. Thermodynamic modeling of the Ca-Sn system based on finite temperature quantities from first-principles and experiment

    International Nuclear Information System (INIS)

    Ohno, M.; Kozlov, A.; Arroyave, R.; Liu, Z.K.; Schmid-Fetzer, R.

    2006-01-01

    The thermodynamic model of the Ca-Sn system was obtained, utilizing the first-principles total energies and heat capacities calculated from 0 K to the melting points of the major phases. Since the first-principles result for the formation energy of the dominating Ca 2 Sn intermetallic phase is drastically different from the reported experimental data, we performed two types of thermodynamic modeling: one based on the first-principles output and the other based on the experimental data. In the former modeling, the Gibbs energies of the intermetallic compounds were fully quantified from the first-principles finite temperature properties and the superiority of the former thermodynamic description is demonstrated. It is shown that it is the combination of finite temperature first-principle calculations and the Calphad modeling tool that provides a sound basis for identifying and deciding on conflicting key thermodynamic data in the Ca-Sn system

  12. Rolling dielectric elastomer actuator with bulged cylindrical shape

    International Nuclear Information System (INIS)

    Potz, Marco; Artusi, Matteo; Soleimani, Maryam; Menon, Carlo; Cocuzza, Silvio; Debei, Stefano

    2010-01-01

    This note presents preliminary investigations on the design and development of a rolling dielectric elastomer actuator (rDEA) with a bulged cylindrical shape. The actuator is based on an inflated silicone-based hollow cylinder consisting of a series of dielectric elastomer actuator sectors. The electrical activation of the sectors changes the shape of the rDEA; the induced geometrical change causes a variation of the position of the rDEA's centre of gravity and a consequent initiation of rolling of the rDEA. This paper presents a simplified parametric analytical model which is used to simulate the quasi-static behaviour of the rDEA. A testing procedure is used to assess the potential rolling performance of the rDEA prototypes. (technical note)

  13. Thermodynamic properties calculation of the flue gas based on its composition estimation for coal-fired power plants

    International Nuclear Information System (INIS)

    Xu, Liang; Yuan, Jingqi

    2015-01-01

    Thermodynamic properties of the working fluid and the flue gas play an important role in the thermodynamic calculation for the boiler design and the operational optimization in power plants. In this study, a generic approach to online calculate the thermodynamic properties of the flue gas is proposed based on its composition estimation. It covers the full operation scope of the flue gas, including the two-phase state when the temperature becomes lower than the dew point. The composition of the flue gas is online estimated based on the routinely offline assays of the coal samples and the online measured oxygen mole fraction in the flue gas. The relative error of the proposed approach is found less than 1% when the standard data set of the dry and humid air and the typical flue gas is used for validation. Also, the sensitivity analysis of the individual component and the influence of the measurement error of the oxygen mole fraction on the thermodynamic properties of the flue gas are presented. - Highlights: • Flue gas thermodynamic properties in coal-fired power plants are online calculated. • Flue gas composition is online estimated using the measured oxygen mole fraction. • The proposed approach covers full operation scope, including two-phase flue gas. • Component sensitivity to the thermodynamic properties of flue gas is presented.

  14. An optimization method for gas refrigeration cycle based on the combination of both thermodynamics and entransy theory

    International Nuclear Information System (INIS)

    Chen, Qun; Xu, Yun-Chao; Hao, Jun-Hong

    2014-01-01

    Highlights: • An optimization method for practical thermodynamic cycle is developed. • The entransy-based heat transfer analysis and thermodynamic analysis are combined. • Theoretical relation between system requirements and design parameters is derived. • The optimization problem can be converted into conditional extremum problem. • The proposed method provides several useful optimization criteria. - Abstract: A thermodynamic cycle usually consists of heat transfer processes in heat exchangers and heat-work conversion processes in compressors, expanders and/or turbines. This paper presents a new optimization method for effective improvement of thermodynamic cycle performance with the combination of entransy theory and thermodynamics. The heat transfer processes in a gas refrigeration cycle are analyzed by entransy theory and the heat-work conversion processes are analyzed by thermodynamics. The combination of these two analysis yields a mathematical relation directly connecting system requirements, e.g. cooling capacity rate and power consumption rate, with design parameters, e.g. heat transfer area of each heat exchanger and heat capacity rate of each working fluid, without introducing any intermediate variable. Based on this relation together with the conditional extremum method, we theoretically derive an optimization equation group. Simultaneously solving this equation group offers the optimal structural and operating parameters for every single gas refrigeration cycle and furthermore provides several useful optimization criteria for all the cycles. Finally, a practical gas refrigeration cycle is taken as an example to show the application and validity of the newly proposed optimization method

  15. Monitoring and Mapping the Galactic Bulge

    Science.gov (United States)

    Markwardt, Craig

    Both neutron star and black hole binary transients are providing some of the most exciting RXTE science, and fortunately many are concentrated in the galactic bulge region. We propose to continue our twice weekly PCA scans of the region, which cover about 500 sq deg. The observations will be sensitive to new sources at the ~1 mCrab level (a factor of 10-60 more sensitive than the ASM in the region). We have had success finding new sources and new types of variability, including three millisecond pulsars, and new increased solid angle will improve the chances of finding more in the final RXTE years. We will continue efforts to search for variability in new and known sources. Companion follow-up proposals would be triggered by the results.

  16. Stellar and Gaseous Kinematics of Seyfert Galaxies. II. The Role of the Bulge

    Science.gov (United States)

    Nelson, Charles H.; Whittle, Mark

    1996-07-01

    We have used measurements of the nuclear stellar velocity dispersion, σ_*_, for a large sample of Seyfert galaxies to investigate the role played by the nuclear gravitational potential in defining the properties of active galaxies. We address four basic questions. First, do Seyferts have unusual nuclear stellar dynamical properties compared to those of normal galaxies? Second, what are the relative contributions of gravitational and nongravitational forces creating the velocity field of the nuclear emission-line gas? Third, how do the emission-line and radio luminosities in the narrow-line region (NLR) depend on the bulge potential? Fourth, in what way are the properties of Seyfert galaxies related to those of radio galaxies? We find that Seyferts define a tight correlation between σ_*_ and bulge absolute magnitude, similar to the Faber-Jackson relation for normal spiral bulges. We infer from this that Seyfert bulges are kinematically normal. The Seyfert relation is, however, offset to higher bulge luminosities, which we interpret as evidence for a lower mean mass- to-light ratio. Either Seyferts have experienced higher than average star formation or they avoid systems with older stellar populations. We analyze the relations between σ_*_ and both galaxy rotation and galaxy absolute magnitude, finding similar relations to those of normal spirals. This also supports a normal kinematic relation between bulges and disks in Seyferts. A moderately strong correlation between σ_*_ and [O III] profile width suggests that gravitational motion plays an important role in the NLR velocity field. The correlation is weaker with [O III] base and wing widths, although the interpretation of this is not yet clear. The remaining real scatter on the relations indicates the importance of other factors. In particular, objects with kiloparsec-scale linear radio sources can have significantly broader [O III] lines, confirming that interaction with an expanding radio source can

  17. The effectiveness of problem-based learning on teaching the first law of thermodynamics

    Science.gov (United States)

    Tatar, Erdal; Oktay, Münir

    2011-11-01

    Background: Problem-based learning (PBL) is a teaching approach working in cooperation with self-learning and involving research to solve real problems. The first law of thermodynamics states that energy can neither be created nor destroyed, but that energy is conserved. Students had difficulty learning or misconceptions about this law. This study is related to the teaching of the first law of thermodynamics within a PBL environment. Purpose: This study examined the effectiveness of PBL on candidate science teachers' understanding of the first law of thermodynamics and their science process skills. This study also examined their opinions about PBL. Sample: The sample consists of 48 third-grade university students from the Department of Science Education in one of the public universities in Turkey. Design and methods: A one-group pretest-posttest experimental design was used. Data collection tools included the Achievement Test, Science Process Skill Test, Constructivist Learning Environment Survey and an interview with open-ended questions. Paired samples t-test was conducted to examine differences in pre/post tests. Results: The PBL approach has a positive effect on the students' learning abilities and science process skills. The students thought that the PBL environment supports effective and permanent learning, and self-learning planning skills. On the other hand, some students think that the limited time and unfamiliarity of the approach impede learning. Conclusions: The PBL is an active learning approach supporting students in the process of learning. But there are still many practical disadvantages that could reduce the effectiveness of the PBL. To prevent the alienation of the students, simple PBL activities should be applied from the primary school level. In order to overcome time limitations, education researchers should examine short-term and effective PBL activities.

  18. Thermodynamic and kinetic investigation of a chemical reaction-based miniature heat pump

    International Nuclear Information System (INIS)

    Flueckiger, Scott M.; Volle, Fabien; Garimella, Suresh V.; Mongia, Rajiv K.

    2012-01-01

    Highlights: ► Thermodynamic equilibrium inhibits sustainability of reaction-based cooling loop. ► Closed-loop pervaporation process proposed to exceed thermodynamic equilibrium. ► Low second-law efficiencies associated with system volume minimization. - Abstract: Representative reversible endothermic chemical reactions (paraldehyde depolymerization and 2-proponal dehydrogenation) are theoretically assessed for their use in a chemical heat pump design for compact thermal management applications. Equilibrium and dynamic simulations are undertaken to explore the operation of the heat pump which upgrades waste heat from near room temperature by approximately 20° in a minimized system volume. A model is developed based on system mass and energy balances coupled with kinetic equations to ascertain mixture conditions at each state point in the loop, as well as mass flow rate, minimum work input, and minimum endothermic reactor volume according to defined reservoir temperatures and desired heat load. Assuming that a pervaporation process is employed in both reaction systems to achieve the requisite mixture compositions for sustained operation, the simulations show that the chemical heat pump can pump 5 W of power with endothermic reactor volumes of as little as 60–93 cm 3 , depending on the selected chemical reaction. Low exergy efficiencies remain a significant design consequence, but the system performance in terms of environmental impact and COP are comparable with, and in some cases better than, the performance of alternative technologies under the same conditions.

  19. Cementing the foundations of thermodynamics: Comparison of system-based and surroundings-based definitions of work and heat

    International Nuclear Information System (INIS)

    Gislason, Eric A.; Craig, Norman C.

    2005-01-01

    The distinction between system-based and surroundings-based definitions of thermodynamic heat (q) and work (w), particularly pressure-volume work, in irreversible processes is introduced and cleanly drawn. A systematic presentation of system-based q and w is given for the first time. This development complements the authors' earlier presentation of surroundings-based work and heat. Either set of definitions can and has been used to develop the laws of thermodynamics. Both sets of definitions are used to analyze examples presented by Kivelson and Oppenheim (KO). It is seen for two KO processes that w(sys-based) and w(surr-based) are not equal. This not uncommon result does not violate the first law because the two q values are also different. One of the KO examples corresponds to a 'quasistatic' process, which is reversible from the point of view of the system but not from the point of view of the system plus surroundings taken together, and, therefore, not reversible overall. A number of reasons are given for preferring surroundings-based definitions of w and q to system-based definitions. Perhaps the most important is the fact that w(sys-based) does not always satisfy the theorem of maximum work in a constant temperature process. Finally, an explanation is presented for why the common use of two different sets of definitions for w and q has not led to greater confusion in the past

  20. The development of platinum-based alloys and their thermodynamic database

    Directory of Open Access Journals (Sweden)

    Cornish L.A.

    2002-01-01

    Full Text Available A series of quaternary platinum-based alloys have been demonstrated to exhibit the same two-phase structure as Ni-based superalloys and showed good mechanical properties. The properties of ternary alloys were a good indication that the quaternary alloys, with their better microstructure, will be even better. The quaternary alloy composition has been optimised at Pt84:Al11:Ru2:Cr3 for the best microstructure and hardness. Work has begun on establishing a thermodynamic database for Pt-Al-Ru-Cr alloys, and further work will be done to enhance the mechanical and oxidation properties of the alloys by adding small amounts of other elements to the base composition of Pt84:Al11:Ru2:Cr3.

  1. Thermodynamic investigation of waste heat driven desalination unit based on humidification dehumidification (HDH) processes

    International Nuclear Information System (INIS)

    He, W.F.; Xu, L.N.; Han, D.; Gao, L.; Yue, C.; Pu, W.H.

    2016-01-01

    Highlights: • HDH desalination system powered by waste heat is proposed. • Performance of the desalination unit and the relevant heat recovery effect is calculated. • Sensitive analysis of the performance for the HDH desalination system is investigated. • Mathematical model based on the first and second laws of thermodynamics is established. - Abstract: Humidification dehumidification (HDH) technology is an effective pattern to separate freshwater from seawater or brackish water. In this paper, a closed-air open-water (CAOW) desalination unit coupled with plate heat exchangers (PHEs) is applied to recover the waste heat from the gas exhaust. Sensitivity analysis for the HDH desalination unit as well as the PHEs from the key parameters including the top and initial temperature of the seawater, operation pressure, and the terminal temperature difference (TTD) of the PHEs are accomplished, and the corresponding performance of the whole HDH desalination system is calculated and presented. The simulation results show that the balance condition of the dehumidifier is allowed by the basic thermodynamic laws, followed by a peak value of gained-output-ratio (GOR) and a bottom value of total specific entropy generation. It is concluded that excellent results including the system performance, heat recovery effect and investment of the PHEs can be simultaneously obtained with a low top temperature, while the obtained desalination performance and the heat recovery effect from other measures are always conflicting. Different from other parameters of the desalination unit, the terminal temperature difference of the PHEs has little influences on the final value of GOR.

  2. A Thermodynamically-consistent FBA-based Approach to Biogeochemical Reaction Modeling

    Science.gov (United States)

    Shapiro, B.; Jin, Q.

    2015-12-01

    Microbial rates are critical to understanding biogeochemical processes in natural environments. Recently, flux balance analysis (FBA) has been applied to predict microbial rates in aquifers and other settings. FBA is a genome-scale constraint-based modeling approach that computes metabolic rates and other phenotypes of microorganisms. This approach requires a prior knowledge of substrate uptake rates, which is not available for most natural microbes. Here we propose to constrain substrate uptake rates on the basis of microbial kinetics. Specifically, we calculate rates of respiration (and fermentation) using a revised Monod equation; this equation accounts for both the kinetics and thermodynamics of microbial catabolism. Substrate uptake rates are then computed from the rates of respiration, and applied to FBA to predict rates of microbial growth. We implemented this method by linking two software tools, PHREEQC and COBRA Toolbox. We applied this method to acetotrophic methanogenesis by Methanosarcina barkeri, and compared the simulation results to previous laboratory observations. The new method constrains acetate uptake by accounting for the kinetics and thermodynamics of methanogenesis, and predicted well the observations of previous experiments. In comparison, traditional methods of dynamic-FBA constrain acetate uptake on the basis of enzyme kinetics, and failed to reproduce the experimental results. These results show that microbial rate laws may provide a better constraint than enzyme kinetics for applying FBA to biogeochemical reaction modeling.

  3. Land use impact evaluation in life cycle assessment based on ecosystem thermodynamics

    International Nuclear Information System (INIS)

    Wagendorp, Tim; Gulinck, Hubert; Coppin, Pol; Muys, Bart

    2006-01-01

    Life Cycle Assessment (LCA) studies of products with a major part of their life cycle in biological production systems (i.e. forestry and agriculture) are often incomplete because the assessment of the land use impact is not operational. Most method proposals include the quality of the land in a descriptive way using rank scores for an arbitrarily selected set of indicators. This paper first offers a theoretical framework for the selection of suitable indicators for land use impact assessment, based on ecosystem thermodynamics. According to recent theories on the thermodynamics of open systems, a goal function of ecosystems is to maximize the dissipation of exogenic exergy fluxes by maximizing the internal exergy storage under form of biomass, biodiversity and complex trophical networks. Human impact may decrease this ecosystem exergy level by simplification, i.e. decreasing biomass and destroying internal complexity. Within this theoretical framework, we then studied possibilities for assessing the land use impact in a more direct way by measuring the ecosystems' capacity to dissipate solar exergy. Measuring ecosystem thermal characteristics by using remote sensing techniques was considered a promising tool. Once operational, it could offer a quick and cheap alternative to quantify land use impacts in any terrestrial ecosystem of any size. Recommendations are given for further exploration of this method and for its integration into an ISO compatible LCA framework

  4. High-temperature thermodynamics by laser-vaporization mass spectrometry: An approach based on statistical mechanics

    International Nuclear Information System (INIS)

    Belloni, Fabio; Manara, Dario; Pflieger, Rachel; Colle, Jean-Yves; Rondinella, Vincenzo V.

    2008-01-01

    The problem of correlation between the temperature of the target surface and the mass-spectrometer signal in laser-vaporization mass spectrometry has been analyzed theoretically. An approach based on statistical mechanics has been applied in order to describe the transient vaporization into vacuum of molecules effused from the area of the target surface struck by a laser pulse of moderate power density and time duration of some tens of ms (Langmuir vaporization). In particular, an expression for the intensity of the output signal of the mass spectrometer, I(l,t), has been derived as a function of the detection time, t, and of the distance, l, of the ionizing chamber of the spectrometer from the target. A simple numerical method for the calculation of I(l,t) according to the time profile of the target temperature is also provided. By fitting experimental I(t) values with the theoretical expression one can retrieve thermodynamic quantities involved in the sublimation/evaporation process of the molecular species analyzed, such as enthalpy and equilibrium vapor pressure (or, alternatively, vaporization coefficient). As an illustration, this fitting was performed on experimental measurements of pyrolytic graphite sublimation in the temperature range 3200-3700 K. The analysis developed will be useful for the interpretation of experimental datasets in order to retrieve high-temperature thermodynamic data, especially on high-melting materials. Research in this domain is being launched for nuclear materials, particularly for Generation IV advanced fuels

  5. The formation of the Galactic bulge of the Milky Way

    Directory of Open Access Journals (Sweden)

    Freeman K.

    2012-02-01

    Full Text Available We aim to determine if the bulge formed via mergers as predicted by Cold Dark Matter (CDM theory, or from disk instabilities, as suggested by its boxy shape, or both processes. We are observing about 28,000 bulge stars in fields that span longitudes of − 31 to + 26° and latitudes of − 5° to − 10°, targeting mostly red clump giants and we are measuring stellar velocities and chemical abundances. We have almost concluded our observations and have analysed data of 23,000 stars. We find a cylindrical rotation profile for the bulge which blends smoothly out into the disk and from the [Fe/H] results we find the bulge to be comprised of separate components, with an underlying slowly rotating metal poor subsample which we believe to be the inner halo stars and metal weak thick disk. We find only a small [Fe/H] gradient with latitude in the bulge, of − 0.07dex/kpc. This weak gradient does not necessarily support a merger origin for our bulge and the composite nature of the bulge is consistent with formation out of the thin disk as per instability formation models.

  6. Statistical thermodynamics

    International Nuclear Information System (INIS)

    Lim, Gyeong Hui

    2008-03-01

    This book consists of 15 chapters, which are basic conception and meaning of statistical thermodynamics, Maxwell-Boltzmann's statistics, ensemble, thermodynamics function and fluctuation, statistical dynamics with independent particle system, ideal molecular system, chemical equilibrium and chemical reaction rate in ideal gas mixture, classical statistical thermodynamics, ideal lattice model, lattice statistics and nonideal lattice model, imperfect gas theory on liquid, theory on solution, statistical thermodynamics of interface, statistical thermodynamics of a high molecule system and quantum statistics

  7. Telon Blue AGLF Adsorption by NiO Based Nanomaterials:Equilibrium, Kinetic And Thermodynamic Approach

    Directory of Open Access Journals (Sweden)

    Gizem Biçer

    2017-06-01

    Full Text Available In this study, the effects of adsorption parameters such as initial pH, initial dye concentration, temperature and adsorbent dosage on the colour removal from aqueous solution containing Telon Blue AGLF(TB AGLF textile dye were investigated by NiO based nanomaterials and then the compliance of the equilibrium data with the different isotherm models in the literature was evaluated. In the next step, the adsorption sytem was analyzed in terms of kinetics and thermodynamics. At the end of the study, XRD, SEM and FTIR analysis methods were used for the particle characterization. As a result of the experimental studies, it was detected the successful use of NiO based nanomaterials synthesized by aqueous solution method rarely seen in literature for colour removal. Through this study, it is believed that the additional contributions are provided to the scientific investigations about the recovery of the water resources.

  8. Solvation thermodynamics

    CERN Document Server

    Ben-Naim, Arieh

    1987-01-01

    This book deals with a subject that has been studied since the beginning of physical chemistry. Despite the thousands of articles and scores of books devoted to solvation thermodynamics, I feel that some fundamen­ tal and well-established concepts underlying the traditional approach to this subject are not satisfactory and need revision. The main reason for this need is that solvation thermodynamics has traditionally been treated in the context of classical (macroscopic) ther­ modynamics alone. However, solvation is inherently a molecular pro­ cess, dependent upon local rather than macroscopic properties of the system. Therefore, the starting point should be based on statistical mechanical methods. For many years it has been believed that certain thermodynamic quantities, such as the standard free energy (or enthalpy or entropy) of solution, may be used as measures of the corresponding functions of solvation of a given solute in a given solvent. I first challenged this notion in a paper published in 1978 b...

  9. Light, Alpha, and Fe-peak Element Abundances in the Galactic Bulge

    Science.gov (United States)

    Johnson, Christian I.; Rich, R. Michael; Kobayashi, Chiaki; Kunder, Andrea; Koch, Andreas

    2014-10-01

    We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+5.25,-3.02) and (0,-12). The (+5.25,-3.02) field also includes observations of the bulge globular cluster NGC 6553. The results are based on high-resolution (R ~ 20,000), high signal-to-noise ration (S/N >~ 70) FLAMES-GIRAFFE spectra obtained through the European Southern Observatory archive. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analyses of this data set beyond Fe and the α-elements Mg, Si, Ca, and Ti. While we find reasonable agreement with past work, the data presented here indicate that the bulge may exhibit a different chemical composition than the local thick disk, especially at [Fe/H] >~ -0.5. In particular, the bulge [α/Fe] ratios may remain enhanced to a slightly higher [Fe/H] than the thick disk, and the Fe-peak elements Co, Ni, and Cu appear enhanced compared to the disk. There is also some evidence that the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be different at low and high metallicity. We also find that the velocity dispersion decreases as a function of increasing [Fe/H] for both fields, and do not detect any significant cold, high-velocity populations. A comparison with chemical enrichment models indicates that a significant fraction of hypernovae may be required to explain the bulge abundance trends, and that initial mass functions that are steep, top-heavy (and do not include strong outflow), or truncated to avoid including contributions from stars >40 M ⊙ are ruled out, in particular because of disagreement with the Fe-peak abundance data. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field stars. However, the

  10. Light, alpha, and Fe-peak element abundances in the galactic bulge

    International Nuclear Information System (INIS)

    Johnson, Christian I.; Rich, R. Michael; Kobayashi, Chiaki; Kunder, Andrea; Koch, Andreas

    2014-01-01

    We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+5.25,–3.02) and (0,–12). The (+5.25,–3.02) field also includes observations of the bulge globular cluster NGC 6553. The results are based on high-resolution (R ∼ 20,000), high signal-to-noise ration (S/N ≳ 70) FLAMES-GIRAFFE spectra obtained through the European Southern Observatory archive. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analyses of this data set beyond Fe and the α-elements Mg, Si, Ca, and Ti. While we find reasonable agreement with past work, the data presented here indicate that the bulge may exhibit a different chemical composition than the local thick disk, especially at [Fe/H] ≳ –0.5. In particular, the bulge [α/Fe] ratios may remain enhanced to a slightly higher [Fe/H] than the thick disk, and the Fe-peak elements Co, Ni, and Cu appear enhanced compared to the disk. There is also some evidence that the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be different at low and high metallicity. We also find that the velocity dispersion decreases as a function of increasing [Fe/H] for both fields, and do not detect any significant cold, high-velocity populations. A comparison with chemical enrichment models indicates that a significant fraction of hypernovae may be required to explain the bulge abundance trends, and that initial mass functions that are steep, top-heavy (and do not include strong outflow), or truncated to avoid including contributions from stars >40 M ☉ are ruled out, in particular because of disagreement with the Fe-peak abundance data. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field stars

  11. Light, alpha, and Fe-peak element abundances in the galactic bulge

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Christian I. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-15, Cambridge, MA 02138 (United States); Rich, R. Michael [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Kobayashi, Chiaki [Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Kunder, Andrea [Leibniz-Institute für Astrophysik Potsdam (AIP), Ander Sternwarte 16, D-14482, Potsdam (Germany); Koch, Andreas, E-mail: cjohnson@cfa.harvard.edu, E-mail: rmr@astro.ucla.edu, E-mail: c.kobayashi@herts.ac.uk, E-mail: akunder@aip.de, E-mail: akoch@lsw.uni-heidelberg.de [Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, Heidelberg (Germany)

    2014-10-01

    We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+5.25,–3.02) and (0,–12). The (+5.25,–3.02) field also includes observations of the bulge globular cluster NGC 6553. The results are based on high-resolution (R ∼ 20,000), high signal-to-noise ration (S/N ≳ 70) FLAMES-GIRAFFE spectra obtained through the European Southern Observatory archive. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analyses of this data set beyond Fe and the α-elements Mg, Si, Ca, and Ti. While we find reasonable agreement with past work, the data presented here indicate that the bulge may exhibit a different chemical composition than the local thick disk, especially at [Fe/H] ≳ –0.5. In particular, the bulge [α/Fe] ratios may remain enhanced to a slightly higher [Fe/H] than the thick disk, and the Fe-peak elements Co, Ni, and Cu appear enhanced compared to the disk. There is also some evidence that the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be different at low and high metallicity. We also find that the velocity dispersion decreases as a function of increasing [Fe/H] for both fields, and do not detect any significant cold, high-velocity populations. A comparison with chemical enrichment models indicates that a significant fraction of hypernovae may be required to explain the bulge abundance trends, and that initial mass functions that are steep, top-heavy (and do not include strong outflow), or truncated to avoid including contributions from stars >40 M {sub ☉} are ruled out, in particular because of disagreement with the Fe-peak abundance data. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field

  12. Formation of the Lunar Fossil Bulges and its Implication for the Early Earth and Moon

    Science.gov (United States)

    Qin, C.; Zhong, S.; Phillips, R. J.

    2017-12-01

    First recognized by Laplace more than two centuries ago, the lunar gravitational and shape anomalies associated with rotational and tidal bulges are significantly larger than predicted from the hydrostatic theory. The harmonic degree-2 gravitational coefficients of the Moon, C20 and C22 (measuring the size of the rotational and tidal bulges), are 17 and 14 times of their hydrostatic counterparts, respectively, after removal of the effect from large impact basins. The bulges are commonly considered as remnant hydrostatic features, "frozen-in" when the Moon was closer to the Earth, experiencing larger tidal-rotational forces. The extant hypothesis is that as the Moon cooled and migrated outwards, a strong outer layer (lithosphere) thickened and reached a stress state that supported the bulges, which no longer tracked the hydrostatic ellipticity. However, this process is poorly understood and an appropriate dynamical model has not been engaged. Here we present the first dynamically self-consistent model of lunar bulge formation that couples a lunar interior thermal evolution model to the tidal-rotational forcing of the Moon. The forcing magnitude decreases with time as the Moon despins on the receding orbit, while the recession rate is controlled by the Earth's tidal dissipation factor Q. Assuming a viscoelastic rheology, the cooling of the Moon is described by a model with high viscosity lithosphere thickening with time. While conventional methods are not suitable for models with time-dependent viscoelastic structure, a semi-analytical method has been developed to address this problem. We show that the bulge formation is controlled by the relative timing of lithosphere thickening and lunar orbit recession. Based on our calculations, we conclude that the development of the fossil bulges may have taken as long as 400 million years after the formation of lunar lithosphere and was complete when the lunar orbit semi-major axis, a, was 32 Earth's radius, RE. We find a

  13. A thermodynamic perspective to study energy performance of vacuum-based membrane dehumidification

    KAUST Repository

    Bui, Thuan Duc

    2017-05-13

    In humid environments, decoupling the latent and sensible cooling loads - dehumidifying - can significantly improve chiller efficiency. Here, a basic limit for dehumidification efficiency is established from fundamental thermodynamics. This is followed by the derivation of how this limit is modified when the pragmatic constraint of a finite flux must be accommodated. These limits allow one to identify promising system modifications, and to quantify their impact. The focus is on vacuum-based membrane dehumidification. New high-efficiency configurations are formulated, most notably, by coupling pumping with condensation. More than an order-of-magnitude improvement in efficiency is achievable. It is contingent on water vapor exiting at its saturation pressure rather than at ambient pressure. Sensitivity studies to recovery ratio, temperature, relative humidity and membrane selectivity are also presented.

  14. Effects of ammonia concentration on the thermodynamic performances of ammonia–water based power cycles

    International Nuclear Information System (INIS)

    Kim, Kyoung Hoon; Han, Chul Ho; Kim, Kyoungjin

    2012-01-01

    The power generation systems using a binary working fluid such as ammonia–water mixture are proven to be the feasible method for utilizing a low-temperature waste heat source. In this work, ammonia–water based Rankine (AWR) regenerative Rankine (AWRR) power generation cycles are comparatively analyzed by investigating the effects of ammonia mass concentration in the working fluid on the thermodynamic performances of systems. Temperature distributions of fluid streams in the heat exchanging devices are closely examined at different levels of ammonia concentration and they might be the most important design consideration in optimizing the power systems using a binary working fluid. The analysis shows that the lower limit of workable ammonia concentration decreases with increasing turbine inlet pressure. Results also show that both the thermal and exergy efficiencies of AWRR system are generally better than those of AWR system, and can have peaks at the minimum allowable ammonia concentrations in the working range of system operation.

  15. Thermodynamic Feasibility of Hydrogen-Rich Gas Production Supported by Iron Based Chemical Looping Process

    Directory of Open Access Journals (Sweden)

    Grzegorz Słowiński

    2016-01-01

    Full Text Available The continuously increasing oil prices as well as stronger environmental regulations regarding greenhouse emissions made the greatest economic powers search a new, price competitive, and environment friendly energy carrier, such as hydrogen. The world research activities in these terms focus on the development of integrated hydrogen and power generating technologies, particularly technologies of hydrogen production from various carbonaceous resources, like methane, coal, biomass, or waste, often combined with carbon dioxide capture. In the paper the thermodynamic analysis of the enhancement of hydrogen production in iron based chemical looping process is presented. In this method, iron oxide is first reduced to iron with a reducing agent, such as carbon oxide, hydrogen, or mixture of both gases (synthesis gas, and then, in the inverse reaction with steam, it is regenerated to iron oxide, and pure stream of hydrogen is produced.

  16. Thermodynamic and transport properties of plasmas including silicon-based compounds

    Science.gov (United States)

    Colonna, G.; D’Angola, A.; Pietanza, L. D.; Capitelli, M.; Pirani, F.; Stevanato, E.; Laricchiuta, A.

    2018-01-01

    The characterization of the thermodynamic and transport properties of plasmas including silicon species could be of great interest for the investigation of many different systems containing the product of the ablation of silicon-based materials. Different plasma systems (pure silicon, silicon–argon, silicon dioxide and silicon carbide) have been investigated in a wide temperature range (103–4 104 K) and for different pressures (1, 10, 30 and 100 atm), relying on the construction of accurate and extended databases of internal energy levels and binary-interaction transport cross sections for the silicon compounds. The results have been compared with the available results in the literature also studying the dependence on the ratio of components.

  17. Analysis of Terminal Metallic Armor Plate Free-Surface Bulging

    National Research Council Canada - National Science Library

    Rapacki, Jr, E. J

    2008-01-01

    An analysis of the bulge formed on the free-surface of the terminal metallic plate of an armor array is shown to lead to reasonable estimates of the armor array's remaining penetration/perforation resistance...

  18. Effect of confining overlay in micro scale laser bulge forming

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Chao; Sun, Sheng; Zhang, Guofang; Song, Libin; Ji, Zhong, E-mail: jizhong@sdu.edu.cn

    2013-11-15

    Micro scale laser bulge forming (μLBF) shows great potential in fabricating high precision and high-aspect-ratio metallic micro components. The present paper investigated the effect of the confining overlay in μLBF experimentally. The surface morphology of micro bulged parts of pure copper foils with and without confining overlay was explored through the scanning electron microscope. The surface features of quartz glasses with different thickness shocked by single and multiple laser pulses were observed using the optical microscope. The effect of thickness of the confining overlay on the maximum bulging height of micro parts was investigated. Experiments reveal that the application of the confining overlay in μLBF has significant influence on both the surface morphology and plastic deformation of micro bulged parts. The change of laser ablation mode is responsible for forming results. In addition, there is a moderate thickness of the confining overlay to induce noticeable plastic deformation without failure.

  19. COBE diffuse infrared background experiment observations of the galactic bulge

    Science.gov (United States)

    Weiland, J. L.; Arendt, R. G.; Berriman, G. B.; Dwek, E.; Freudenreich, H. T.; Hauser, M. G.; Kelsall, T.; Lisse, C. M.; Mitra, M.; Moseley, S. H.

    1994-01-01

    Low angular resolution maps of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 micrometers obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard NASA's Cosmic Background Explorer (COBE) are presented. After correction for extinction and subtraction of an empirical model for the Galactic disk, the surface brightness distribution of the bulge resembles a flattened ellipse with a minor-to-major axis ratio of approximately 0.6. The bulge minor axis scale height is found to be 2.1 deg +/- 0.2 deg for all four near-infrared wavelengths. Asymmetries in the longitudinal distribution of bulge brightness contours are qualitatively consistent with those expected for a triaxial bar with its near end in the first Galactic quadrant (0 deg less than l less than 90 deg). There is no evidence for an out-of-plane tilt of such a bar.

  20. Thermodynamic assessment of integrated biogas-based micro-power generation system

    International Nuclear Information System (INIS)

    Hosseini, Seyed Ehsan; Barzegaravval, Hasan; Wahid, Mazlan Abdul; Ganjehkaviri, Abdolsaeid; Sies, Mohsin Mohd

    2016-01-01

    Highlights: • A thermodynamic modelling of an integrated biogas-based micro-power generation system is reported. • The impact of design parameters on the thermodynamic performance of the system is evaluated. • High turbine inlet temperatures lead the system to the higher energy and exergy efficiency and higher power generation. • Enhancement of GT isentropic efficiency incurs negative effects on the performance of air preheater and heat exchanger. • The rate of power generation increases by the enhancement of steam turbine pressure in ORC. - Abstract: In this paper, a thermodynamic modelling of an integrated biogas (60%CH 4 + 40%CO 2 ) micro-power generation system for electricity generation is reported. This system involves a gas turbine cycle and organic Rankine cycle (ORC) where the wasted heat of gas turbine cycle is recovered by closed ORC. The net output power of the micro-power generation system is fixed at 1.4 MW includes 1 MW power generated by GT and 0.4 MW by ORC. Energy and exergy assessments and related parametric studies are carried out, and parameters that influence on energy and exergy efficiency are evaluated. The performance of the system with respect to variation of design parameters such as combustion air inlet temperature, turbine inlet temperature, compressor pressure ratio, gas turbine isentropic efficiency and compressor isentropic efficiency (from the top cycle) and steam turbine inlet pressure, and condenser pressure (from bottoming cycle) is evaluated. The results reveal that by the increase of gas turbine isentropic efficiency, the outlet temperature of gas turbine decreases which incurs negative impacts on the performance of air preheater and heat exchanger, however the energy and exergy efficiency increases in the whole system. By the increase of air compressor pressure ratio, the energy and exergy of the combined cycle decreases. The exergy efficiency of ORC alters by the variation of gas turbine parameters which can be

  1. Galaxies Grow Their Bulges and Black Holes in Diverse Ways

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Eric F.; Harmsen, Benjamin; D’Souza, Richard [Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109-1107 (United States); Monachesi, Antonela [Max Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching (Germany); Jong, Roelof S. de [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Bailin, Jeremy [Department of Physics and Astronomy, University of Alabama, Box 870324, Tuscaloosa, AL 35487-0324 (United States); Radburn-Smith, David J. [Department of Astronomy, University of Washington, 3910 15th Avenue NE, Seattle, WA 98195 (United States); Holwerda, Benne W., E-mail: ericbell@umich.edu [Department of Physics and Astronomy, University of Louisville, 102 Natural Science Building, Louisville, KY 40292 (United States)

    2017-03-01

    Galaxies with Milky Way–like stellar masses have a wide range of bulge and black hole masses; in turn, these correlate with other properties such as star formation history. While many processes may drive bulge formation, major and minor mergers are expected to play a crucial role. Stellar halos offer a novel and robust measurement of galactic merger history; cosmologically motivated models predict that mergers with larger satellites produce more massive, higher-metallicity stellar halos, reproducing the recently observed stellar halo metallicity–mass relation. We quantify the relationship between stellar halo mass and bulge or black hole prominence using a sample of 18 Milky Way-mass galaxies with newly available measurements of (or limits on) stellar halo properties. There is an order of magnitude range in bulge mass, and two orders of magnitude in black hole mass, at a given stellar halo mass (or, equivalently, merger history). Galaxies with low-mass bulges show a wide range of quiet merger histories, implying formation mechanisms that do not require intense merging activity. Galaxies with massive “classical” bulges and central black holes also show a wide range of merger histories. While three of these galaxies have massive stellar halos consistent with a merger origin, two do not—merging appears to have had little impact on making these two massive “classical” bulges. Such galaxies may be ideal laboratories to study massive bulge formation through pathways such as early gas-rich accretion, violent disk instabilities, or misaligned infall of gas throughout cosmic time.

  2. Process optimization of joining by upset bulging with local heating

    Science.gov (United States)

    Rusch, Michael; Almohallami, Amer; Sviridov, Alexander; Bonk, Christian; Behrens, Bernd-Arno; Bambach, Markus

    2017-10-01

    Joining by upset bulging is a mechanical joining method where axial load is applied to a tube to form two revolving bulges, which clamp the parts to be joined and create a force and form fit. It can be used to join tubes with other structures such as sheets, plates, tubes or profiles of the same or different materials. Other processes such as welding are often limited in joining multi-material assemblies or high-strength materials. With joining by upset bulging at room temperature, the main drawback is the possible initiation of damage (cracks) in the inner buckling zone because of high local stresses and strains. In this paper, a method to avoid the formation of cracks is introduced. Before forming the bulge the tube is locally heated by an induction coil. For the construction steel (E235+N) a maximum temperature of 700 °C was used to avoid phase transformation. For the numerical study of the process the mechanical properties of the tube material were examined at different temperatures and strain rates to determine its flow curves. A parametrical FE model was developed to simulate the bulging process with local heating. Experiments with local heating were executed and metallographic studies of the bulging area were conducted. While specimens heated to 500 °C showed small cracks left, damage-free flanges could be created at 600 and 700 °C. Static testing of damage-free bulges showed improvements in tensile strength and torsion strength compared to bulges formed at room-temperature, while bending and compression behavior remained nearly unchanged. In cyclic testing the locally heated specimens underwent about 3.7 times as many cycles before failure as the specimens formed at room temperature.

  3. A Practical and Fast Method To Predict the Thermodynamic Preference of omega-Transaminase-Based Transformations

    DEFF Research Database (Denmark)

    Meier, Robert J.; Gundersen Deslauriers, Maria; Woodley, John

    2015-01-01

    A simple, easy-to-use, and fast approach method is proposed and validated that can predict whether a transaminase reaction is thermodynamically unfavourable. This allowed us to de-select, in the present case, at least 50% of the reactions because they were thermodynamically unfavourable as confir...

  4. A minimal dissipation type-based classification in irreversible thermodynamics and microeconomics

    Science.gov (United States)

    Tsirlin, A. M.; Kazakov, V.; Kolinko, N. A.

    2003-10-01

    We formulate the problem of finding classes of kinetic dependencies in irreversible thermodynamic and microeconomic systems for which minimal dissipation processes belong to the same type. We show that this problem is an inverse optimal control problem and solve it. The commonality of this problem in irreversible thermodynamics and microeconomics is emphasized.

  5. Thermodynamic analysis of a solar-based multi-generation system with hydrogen production

    International Nuclear Information System (INIS)

    Ozturk, Murat; Dincer, Ibrahim

    2013-01-01

    Thermodynamic analysis of a renewable-based multi-generation energy production system which produces a number of outputs, such as power, heating, cooling, hot water, hydrogen and oxygen is conducted. This solar-based multi-generation system consists of four main sub-systems: Rankine cycle, organic Rankine cycle, absorption cooling and heating, and hydrogen production and utilization. Exergy destruction ratios and rates, power or heat transfer rates, energy and exergy efficiencies of the system components are carried out. Some parametric studies are performed in order to examine the effects of varying operating conditions (e.g., reference temperature, direct solar radiation and receiver temperature) on the exergy efficiencies of the sub-systems as well as the whole system. The solar-based multi-generation system which has an exergy efficiency of 57.35%, is obtained to be higher than using these sub-systems separately. The evaluation of the exergy efficiency and exergy destruction for the sub-systems and the overall system show that the parabolic dish collectors have the highest exergy destruction rate among constituent parts of the solar-based multi-generation system, due to high temperature difference between the working fluid and collector receivers. -- Highlights: ► Development of a new multi-generation system for solar-based hydrogen production. ► Investigation of exergy efficiencies and destructions in each process of the system. ► Evaluation of varying operating conditions on the exergy destruction and efficiency

  6. lncRNATargets: A platform for lncRNA target prediction based on nucleic acid thermodynamics.

    Science.gov (United States)

    Hu, Ruifeng; Sun, Xiaobo

    2016-08-01

    Many studies have supported that long noncoding RNAs (lncRNAs) perform various functions in various critical biological processes. Advanced experimental and computational technologies allow access to more information on lncRNAs. Determining the functions and action mechanisms of these RNAs on a large scale is urgently needed. We provided lncRNATargets, which is a web-based platform for lncRNA target prediction based on nucleic acid thermodynamics. The nearest-neighbor (NN) model was used to calculate binging-free energy. The main principle of NN model for nucleic acid assumes that identity and orientation of neighbor base pairs determine stability of a given base pair. lncRNATargets features the following options: setting of a specific temperature that allow use not only for human but also for other animals or plants; processing all lncRNAs in high throughput without RNA size limitation that is superior to any other existing tool; and web-based, user-friendly interface, and colored result displays that allow easy access for nonskilled computer operators and provide better understanding of results. This technique could provide accurate calculation on the binding-free energy of lncRNA-target dimers to predict if these structures are well targeted together. lncRNATargets provides high accuracy calculations, and this user-friendly program is available for free at http://www.herbbol.org:8001/lrt/ .

  7. The Gaia-ESO Survey: Exploring the complex nature and origins of the Galactic bulge populations

    Science.gov (United States)

    Rojas-Arriagada, A.; Recio-Blanco, A.; de Laverny, P.; Mikolaitis, Š.; Matteucci, F.; Spitoni, E.; Schultheis, M.; Hayden, M.; Hill, V.; Zoccali, M.; Minniti, D.; Gonzalez, O. A.; Gilmore, G.; Randich, S.; Feltzing, S.; Alfaro, E. J.; Babusiaux, C.; Bensby, T.; Bragaglia, A.; Flaccomio, E.; Koposov, S. E.; Pancino, E.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Damiani, F.; Donati, P.; Franciosini, E.; Hourihane, A.; Jofré, P.; Lardo, C.; Lewis, J.; Lind, K.; Magrini, L.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.; Zaggia, S.

    2017-05-01

    not participate in the X-shape bulge. Their Mg enhancement level and general shape in the [Mg/Fe] vs. [Fe/H] plane is comparable to that of the thick disk sequence. The position at which [Mg/Fe] starts to decrease with [Fe/H], called the "knee", is observed in the metal-poor bulge at [Fe/H] knee = -0.37 ± 0.09, being 0.06 dex higher than that of the thick disk. Although this difference is inside the error bars, it suggest a higher star formation rate (SFR) for the bulge than for the thick disk. We estimate an upper limit for this difference of Δ [Fe/H] knee = 0.24 dex. Finally, we present a chemical evolution model that suitably fits the whole bulge sequence by assuming a fast (poor subpopulation might be the product of an early prompt dissipative collapse dominated by massive stars. Nevertheless, our results do not allow us to firmly rule out the possibility that these stars come from the secular evolution of the early thick disk. This is the first time that an analysis of the bulge MDF and α-abundances has been performed in a large area on the basis of a homogeneous, fully spectroscopic analysis of high-resolution, high S/N data. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. These data products have been processed by the Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia-ESO Survey Data Archive, prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council.

  8. Using Thermodynamics to Predict the Outcomes of Nitrate-Based Oil Reservoir Souring Control Interventions

    Directory of Open Access Journals (Sweden)

    Jan Dolfing

    2017-12-01

    Full Text Available Souring is the undesirable production of hydrogen sulfide (H2S in oil reservoirs by sulfate-reducing bacteria (SRB. Souring is a common problem during secondary oil recovery via water flooding, especially when seawater with its high sulfate concentration is introduced. Nitrate injection into these oil reservoirs can prevent and remediate souring by stimulating nitrate-reducing bacteria (NRB. Two conceptually different mechanisms for NRB-facilitated souring control have been proposed: nitrate-sulfate competition for electron donors (oil-derived organics or H2 and nitrate driven sulfide oxidation. Thermodynamics can facilitate predictions about which nitrate-driven mechanism is most likely to occur in different scenarios. From a thermodynamic perspective the question “Which reaction yields more energy, nitrate driven oxidation of sulfide or nitrate driven oxidation of organic compounds?” can be rephrased as: “Is acetate driven sulfate reduction to sulfide exergonic or endergonic?” Our analysis indicates that under conditions encountered in oil fields, sulfate driven oxidation of acetate (or other SRB organic electron donors is always more favorable than sulfide oxidation to sulfate. That predicts that organotrophic NRB that oxidize acetate would outcompete lithotrophic NRB that oxidize sulfide. However, sulfide oxidation to elemental sulfur is different. At low acetate HS− oxidation is more favorable than acetate oxidation. Incomplete oxidation of sulfide to S0 is likely to occur when nitrate levels are low, and is favored by low temperatures; conditions that can be encountered at oil field above-ground facilities where intermediate sulfur compounds like S0 may cause corrosion. These findings have implications for reservoir management strategies and for assessing the success and progress of nitrate-based souring control strategies and the attendant risks of corrosion associated with souring and nitrate injection.

  9. Thermodynamically based solvent design for enzymatic saccharide acylation with hydroxycinnamic acids in non-conventional media.

    Science.gov (United States)

    Zeuner, Birgitte; Kontogeorgis, Georgios M; Riisager, Anders; Meyer, Anne S

    2012-02-15

    Enzyme-catalyzed synthesis has been widely studied with lipases (EC 3.1.1.3), but feruloyl esterases (FAEs; EC 3.1.1.73) may provide advantages such as higher substrate affinity and regioselectivity in the synthesis of hydroxycinnamate saccharide esters. These compounds are interesting because of their amphiphilicity and antioxidative potential. Synthetic reactions using mono- or disaccharides as one of the substrates may moreover direct new routes for biomass upgrading in the biorefinery. The paper reviews the available data for enzymatic hydroxycinnamate saccharide ester synthesis in organic solvent systems as well as other enzymatic hydroxycinnamate acylations in ionic liquid systems. The choice of solvent system is highly decisive for enzyme stability, selectivity, and reaction yields in these synthesis reactions. To increase the understanding of the reaction environment and to facilitate solvent screening as a crucial part of the reaction design, the review explores the use of activity coefficient models for describing these systems and - more importantly - the use of group contribution model UNIFAC and quantum chemistry based COSMO-RS for thermodynamic predictions and preliminary solvent screening. Surfactant-free microemulsions of a hydrocarbon, a polar alcohol, and water are interesting solvent systems because they accommodate different substrate and product solubilities and maintain enzyme stability. Ionic liquids may provide advantages as solvents in terms of increased substrate and product solubility, higher reactivity and selectivity, as well as tunable physicochemical properties, but their design should be carefully considered in relation to enzyme stability. The treatise shows that thermodynamic modeling tools for solvent design provide a new toolbox to design enzyme-catalyzed synthetic reactions from biomass sources. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Using Thermodynamics to Predict the Outcomes of Nitrate-Based Oil Reservoir Souring Control Interventions

    Science.gov (United States)

    Dolfing, Jan; Hubert, Casey R. J.

    2017-01-01

    Souring is the undesirable production of hydrogen sulfide (H2S) in oil reservoirs by sulfate-reducing bacteria (SRB). Souring is a common problem during secondary oil recovery via water flooding, especially when seawater with its high sulfate concentration is introduced. Nitrate injection into these oil reservoirs can prevent and remediate souring by stimulating nitrate-reducing bacteria (NRB). Two conceptually different mechanisms for NRB-facilitated souring control have been proposed: nitrate-sulfate competition for electron donors (oil-derived organics or H2) and nitrate driven sulfide oxidation. Thermodynamics can facilitate predictions about which nitrate-driven mechanism is most likely to occur in different scenarios. From a thermodynamic perspective the question “Which reaction yields more energy, nitrate driven oxidation of sulfide or nitrate driven oxidation of organic compounds?” can be rephrased as: “Is acetate driven sulfate reduction to sulfide exergonic or endergonic?” Our analysis indicates that under conditions encountered in oil fields, sulfate driven oxidation of acetate (or other SRB organic electron donors) is always more favorable than sulfide oxidation to sulfate. That predicts that organotrophic NRB that oxidize acetate would outcompete lithotrophic NRB that oxidize sulfide. However, sulfide oxidation to elemental sulfur is different. At low acetate HS− oxidation is more favorable than acetate oxidation. Incomplete oxidation of sulfide to S0 is likely to occur when nitrate levels are low, and is favored by low temperatures; conditions that can be encountered at oil field above-ground facilities where intermediate sulfur compounds like S0 may cause corrosion. These findings have implications for reservoir management strategies and for assessing the success and progress of nitrate-based souring control strategies and the attendant risks of corrosion associated with souring and nitrate injection. PMID:29312252

  11. Formulation based on artificial neural network of thermodynamic properties of ozone friendly refrigerant/absorbent couples

    International Nuclear Information System (INIS)

    Soezen, Adnan; Arcaklioglu, Erol; Oezalp, Mehmet

    2005-01-01

    This paper presents a new approach based on artificial neural networks (ANNs) to determine the properties of liquid and two phase boiling and condensing of two alternative refrigerant/absorbent couples (methanol/LiBr and methanol/LiCl). These couples do not cause ozone depletion and use in the absorption thermal systems (ATSs). ANNs are able to learn the key information patterns within multidimensional information domain. ANNs operate such as a 'black box' model, requiring no detailed information about the system. On the other hand, they learn the relationship between the input and the output. In order to train the neural network, limited experimental measurements were used as training data and test data. In this study, in input layer, there are temperatures in the range of 298-498 K, pressures (0.1-40 MPa) and concentrations of 2%, 7%, 12% of the couples; specific volume is in output layer. The back-propagation learning algorithm with three different variants, namely scaled conjugate gradient (SCG), Pola-Ribiere conjugate gradient (CGP), and Levenberg-Marquardt (LM), and logistic sigmoid transfer function were used in the network so that the best approach can find. The most suitable algorithm and neuron number in the hidden layer are found as SCG with 8 neurons. For this number level, after the training, it is found that maximum error is less than 3%, average error is about 1% and R 2 value are 99.999%. As seen from the results obtained the thermodynamic equations for each pair by using the weights of network have been obviously predicted within acceptable errors. This paper shows that values predicted with ANN can be used to define the thermodynamic properties instead of approximate and complex analytic equations

  12. Surface thermodynamics

    International Nuclear Information System (INIS)

    Garcia-Moliner, F.

    1975-01-01

    Basic thermodynamics of a system consisting of two bulk phases with an interface. Solid surfaces: general. Discussion of experimental data on surface tension and related concepts. Adsorption thermodynamics in the Gibbsian scheme. Adsorption on inert solid adsorbents. Systems with electrical charges: chemistry and thermodynamics of imperfect crystals. Thermodynamics of charged surfaces. Simple models of charge transfer chemisorption. Adsorption heat and related concepts. Surface phase transitions

  13. The nearest neighbor and next nearest neighbor effects on the thermodynamic and kinetic properties of RNA base pair

    Science.gov (United States)

    Wang, Yujie; Wang, Zhen; Wang, Yanli; Liu, Taigang; Zhang, Wenbing

    2018-01-01

    The thermodynamic and kinetic parameters of an RNA base pair with different nearest and next nearest neighbors were obtained through long-time molecular dynamics simulation of the opening-closing switch process of the base pair near its melting temperature. The results indicate that thermodynamic parameters of GC base pair are dependent on the nearest neighbor base pair, and the next nearest neighbor base pair has little effect, which validated the nearest-neighbor model. The closing and opening rates of the GC base pair also showed nearest neighbor dependences. At certain temperature, the closing and opening rates of the GC pair with nearest neighbor AU is larger than that with the nearest neighbor GC, and the next nearest neighbor plays little role. The free energy landscape of the GC base pair with the nearest neighbor GC is rougher than that with nearest neighbor AU.

  14. On thermodynamics of rhenium ion exchange sorption by strong-base anionite from nitrate-sulfate solutions

    International Nuclear Information System (INIS)

    Blokhin, A.A.; Pak, V.I.; Siracheva, M.K.

    1984-01-01

    The apparent thermodynamic parameters of the process of rhenium absorption by strong-base anionites from nitrate-sulfate media in the range of low degrees of filling the sorbents with perrhenate ions are estimated. On the basis of studying the temperature dependence of ion-exchange rhenium sorption it is shown that this process is accompanied by heat release and entropy reduction

  15. Stability range of MoC (hp2). II. Thermodynamic properties of generalized Lewis acid-base intermetallics

    International Nuclear Information System (INIS)

    Koukouvetakis, J.

    1988-01-01

    The γ-MoC phase with the hexagonal WC structure was prepared without the presence of metal stabilizers at temperatures below 1000 degree C. This phase was found to be thermodynamically stable at low temperatures and decomposed to Mo 2 C and graphite at 1400 K. Using equilibrium and thermodynamic data, the thermodynamic quantities of this phase were calculated. Oxide equilibration and solid-state galvanic cell experiments were used to study thermodynamic properties of binary Lewis acid-base stabilized transition-metal alloys. The activity of vanadium was determined in alloys of vanadium with platinum-group metals such as Rh, Pd, and Ir at 1000 degree C. The activities of titanium in titanium-iridium alloys and of niobium in Nb 3 Ir were determined at 1400 degree C. The ternary phase diagram of V-Pd-O at 1000 degree C was obtained. Based on the vanadium-palladium results, a partial titration curve of palladium by vanadium was constructed. The excess partial molar Gibbs free energy of vanadium at infinite dilution was found to be -36.4 kcal mol -1 at 1000 degree C. Results are in agreement with the predictions of Brewer's theory of transition-metal alloy acid-base behavior

  16. The Gaia-ESO Survey: Low-α element stars in the Galactic bulge

    Science.gov (United States)

    Recio-Blanco, A.; Rojas-Arriagada, A.; de Laverny, P.; Mikolaitis, S.; Hill, V.; Zoccali, M.; Fernández-Trincado, J. G.; Robin, A. C.; Babusiaux, C.; Gilmore, G.; Randich, S.; Alfaro, E.; Allende Prieto, C.; Bragaglia, A.; Carraro, G.; Jofré, P.; Lardo, C.; Monaco, L.; Morbidelli, L.; Zaggia, S.

    2017-06-01

    We take advantage of the Gaia-ESO Survey iDR4 bulge data to search for abundance anomalies that could shed light on the composite nature of the Milky Way bulge. The α-element (Mg, Si, and whenever available, Ca) abundances, and their trends with Fe abundances have been analysed for a total of 776 bulge stars. In addition, the aluminum abundances and their ratio to Fe and Mg have also been examined. Our analysis reveals the existence of low-α element abundance stars with respect to the standard bulge sequence in the [α/ Fe] versus [Fe/H] plane. Eighteen objects present deviations in [α/ Fe] ranging from 2.1 to 5.3σ with respect to the median standard value. Those stars do not show Mg-Al anti-correlation patterns. Incidentally, this sign of the existence of multiple stellar populations is reported firmly for the first time for the bulge globular cluster NGC 6522. The identified low-α abundance stars have chemical patterns that are compatible with those of the thin disc. Their link with massive dwarf galaxies accretion seems unlikely, as larger deviations in α abundance and Al would be expected. The vision of a bulge composite nature and a complex formation process is reinforced by our results. The approach used, which is a multi-method and model-driven analysis of high resolution data, seems crucial to reveal this complexity. Based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. These data products have been processed by the Cambridge Astronomy Survey Unit (CASU) at the Institute of Astronomy, University of Cambridge, and by the FLAMES/UVES reduction team at INAF/Osservatorio Astrofisico di Arcetri. These data have been obtained from the Gaia-ESO Survey Data Archive, and prepared and hosted by the Wide Field Astronomy Unit, Institute for Astronomy, University of Edinburgh, which is funded by the UK Science and Technology Facilities Council.

  17. Refrigerant flow characteristics of electronic expansion valve based on thermodynamic analysis and experiment

    International Nuclear Information System (INIS)

    Xue Zhifang; Shi Lin; Ou Hongfei

    2008-01-01

    A mass flow correlation for R134a through an EEV (electronic expansion valve) is developed from extensive experimental data. The refrigerant mass flow characteristics of the EEV are an important issue in heat pump/refrigeration system operation because the valve regulates the refrigerant flow to match various operating conditions. Based on the throttling mechanism and thermodynamic analysis, the mass flow rate is a function of various parameters. The selected decision parameters include the valve's geometric parameters, the inlet refrigerant pressure and temperature, the outlet refrigerant pressure, and the refrigerant thermophysical properties represented by the dynamic viscosity and the surface tension, which are sufficient and irredundant for determining the flow coefficient. Because these parameters have very complex and coupled effects on the mass flow characteristics, two combined non-dimensional parameters are defined to describe the coupled effects based on the influence and uncertainty analysis of parameters. The experimental results illustrate that the defined non-dimensional parameters can reveal the EEV flow characteristics correctly. Then, the semi-theoretical flow coefficient correlation with respect to the defined non-dimensional parameters is proposed and identified from several hundred sets of experimental samples using multivariable regression analysis. The proposed correlation agrees well with experimental data for R134a within a wide range of operating conditions. The investigation method in this paper can be adopted by the flow characteristics studies for other types of the EEVs and refrigerants

  18. Analysis of the Glass-Forming Ability of Fe-Er Alloys, Based on Thermodynamic Modeling

    Science.gov (United States)

    Arutyunyan, N. A.; Zaitsev, A. I.; Dunaev, S. F.; Kalmykov, K. B.; El'nyakov, D. D.; Shaposhnikov, N. G.

    2018-05-01

    The Fe-Er phase diagram and thermodynamic properties of all its phases are assessed by means of self-consistent analysis. To refine the data on phase equilibria in the Fe-Er system, an investigation is performed in the 10-40 at % range of Er concentrations. The temperature-concentration dependences of the thermodynamic properties of a melt are presented using the model of ideal associated solutions. Thermodynamic parameters of each phase are obtained, and the calculated results are in agreement with available experimental data. The correlation between the thermodynamic properties of liquid Fe-Er alloys and their tendency toward amorphization are studied. It is shown that compositions of amorphous alloys prepared by melt quenching coincide with the ranges of concentration with the predominance of Fe3Er and FeEr2 associative groups that have large negative entropies of formation.

  19. Advancing viral RNA structure prediction: measuring the thermodynamics of pyrimidine-rich internal loops.

    Science.gov (United States)

    Phan, Andy; Mailey, Katherine; Saeki, Jessica; Gu, Xiaobo; Schroeder, Susan J

    2017-05-01

    Accurate thermodynamic parameters improve RNA structure predictions and thus accelerate understanding of RNA function and the identification of RNA drug binding sites. Many viral RNA structures, such as internal ribosome entry sites, have internal loops and bulges that are potential drug target sites. Current models used to predict internal loops are biased toward small, symmetric purine loops, and thus poorly predict asymmetric, pyrimidine-rich loops with >6 nucleotides (nt) that occur frequently in viral RNA. This article presents new thermodynamic data for 40 pyrimidine loops, many of which can form UU or protonated CC base pairs. Uracil and protonated cytosine base pairs stabilize asymmetric internal loops. Accurate prediction rules are presented that account for all thermodynamic measurements of RNA asymmetric internal loops. New loop initiation terms for loops with >6 nt are presented that do not follow previous assumptions that increasing asymmetry destabilizes loops. Since the last 2004 update, 126 new loops with asymmetry or sizes greater than 2 × 2 have been measured. These new measurements significantly deepen and diversify the thermodynamic database for RNA. These results will help better predict internal loops that are larger, pyrimidine-rich, and occur within viral structures such as internal ribosome entry sites. © 2017 Phan et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  20. Principles of hyperplasticity an approach to plasticity theory based on thermodynamic principles

    CERN Document Server

    Houlsby, Guy T

    2007-01-01

    A new approach to plasticity theory firmly routed in and compatible with the laws of thermodynamicsProvides a common basis for the formulation and comparison of many existing plasticity modelsIncorporates and introduction to elasticity, plasticity, thermodynamics and their interactionsShows the reader how to formulate constitutive models completely specified by two scalar potential functions from which the incremental responses of any hyperplastic model can be derived.

  1. The Black Hole Mass-Bulge Luminosity Relationship for Active Galactic Nuclei From Reverberation Mapping and Hubble Space Telescope Imaging

    DEFF Research Database (Denmark)

    Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.

    2009-01-01

    We investigate the relationship between black hole mass and bulge luminosity for active galactic nuclei (AGNs) with reverberation-based black hole mass measurements and bulge luminosities from two-dimensional decompositions of Hubble Space Telescope host galaxy images. We find that the slope...... of the relationship for AGNs is 0.76-0.85 with an uncertainty of ~0.1, somewhat shallower than the M BH vprop L 1.0±0.1 relationship that has been fit to nearby quiescent galaxies with dynamical black hole mass measurements. This difference is somewhat perplexing, as the AGN black hole masses include an overall...

  2. Theory of chemical kinetics and charge transfer based on nonequilibrium thermodynamics.

    Science.gov (United States)

    Bazant, Martin Z

    2013-05-21

    Advances in the fields of catalysis and electrochemical energy conversion often involve nanoparticles, which can have kinetics surprisingly different from the bulk material. Classical theories of chemical kinetics assume independent reactions in dilute solutions, whose rates are determined by mean concentrations. In condensed matter, strong interactions alter chemical activities and create variations that can dramatically affect the reaction rate. The extreme case is that of a reaction coupled to a phase transformation, whose kinetics must depend not only on the order parameter but also on its gradients at phase boundaries. Reaction-driven phase transformations are common in electrochemistry, when charge transfer is accompanied by ion intercalation or deposition in a solid phase. Examples abound in Li-ion, metal-air, and lead-acid batteries, as well as metal electrodeposition-dissolution. Despite complex thermodynamics, however, the standard kinetic model is the Butler-Volmer equation, based on a dilute solution approximation. The Marcus theory of charge transfer likewise considers isolated reactants and neglects elastic stress, configurational entropy, and other nonidealities in condensed phases. The limitations of existing theories recently became apparent for the Li-ion battery material LixFePO4 (LFP). It has a strong tendency to separate into Li-rich and Li-poor solid phases, which scientists believe limits its performance. Chemists first modeled phase separation in LFP as an isotropic "shrinking core" within each particle, but experiments later revealed striped phase boundaries on the active crystal facet. This raised the question: What is the reaction rate at a surface undergoing a phase transformation? Meanwhile, dramatic rate enhancement was attained with LFP nanoparticles, and classical battery models could not predict the roles of phase separation and surface modification. In this Account, I present a general theory of chemical kinetics, developed over

  3. Thermodynamic and economic evaluations of a geothermal district heating system using advanced exergy-based methods

    International Nuclear Information System (INIS)

    Tan, Mehmet; Keçebaş, Ali

    2014-01-01

    Highlights: • Evaluation of a GDHS using advanced exergy-based methods. • Comparison of the results of the conventional and advanced exergy-based methods. • The modified exergetic efficiency and exergoeconomic factor are found as 45% and 13%. • Improvement and total cost-savings potentials are found to be 3% and 14%. • All the pumps have the highest improvement potential and total cost-savings potential. - Abstract: In this paper, a geothermal district heating system (GDHS) is comparatively evaluated in terms of thermodynamic and economic aspects using advanced exergy-based methods to identify the potential for improvement, the interactions among system components, and the direction and potential for energy savings. The actual operational data are taken from the Sarayköy GDHS, Turkey. In the advanced exergetic and exergoeconomic analyses, the exergy destruction and the total operating cost within each component of the system are split into endogenous/exogenous and unavoidable/avoidable parts. The advantages of these analyses over conventional ones are demonstrated. The results indicate that the advanced exergy-based method is a more meaningful and effective tool than the conventional one for system performance evaluation. The exergetic efficiency and the exergoeconomic factor of the overall system for the Sarayköy GDHS were determined to be 43.72% and 5.25% according to the conventional tools and 45.06% and 12.98% according to the advanced tools. The improvement potential and the total cost-savings potential of the overall system were also determined to be 2.98% and 14.05%, respectively. All of the pumps have the highest improvement potential and total cost-savings potential because the pumps were selected to have high power during installation at the Sarayköy GDHS

  4. Deep JHK Photometry and the Infrared Luminosity Function of the Galactic Bulge

    Science.gov (United States)

    Tiede, Glenn P.; Frogel, Jay A.; Terndrup, D. M.

    1995-03-01

    We derive the deepest, most complete near-IR luminosity function for Galactic bulge stars yet obtained based on new JHK photometry for stars in two fields of Baade's Window. When combined with previously published data, we are able to construct a luminosity function over the range 5.5 Blanco, V.M., & Whitford, A.E. 1990, ApJ, 353, 494). Between b = -3 and -12 we find a gradient in [Fe/H] of -0.06 +/- 0.03 dex/degree, consistent with other, independent derivations. We derive a helium abundance for Baade's Window with the R and R(') methods and find that Y = 0.27 +/- 0.03. Finally, we find that the bolometric corrections for bulge K giants (V - K >= 2) are in excellent agreement with empirical derivations based on observations of globular cluster and local field stars. However, for the redder M giants we find, as did Frogel and Whitford 1987, that the bolometric corrections differ by several tenths of a magnitude from those derived for field giants and adopted in the Revised Yale Isochrones. This difference most likely arises from the excess molecular blanketing in the V and I bands of the bulge giants relative to that seen in field stars.

  5. Thermodynamic estimation: Ionic materials

    International Nuclear Information System (INIS)

    Glasser, Leslie

    2013-01-01

    Thermodynamics establishes equilibrium relations among thermodynamic parameters (“properties”) and delineates the effects of variation of the thermodynamic functions (typically temperature and pressure) on those parameters. However, classical thermodynamics does not provide values for the necessary thermodynamic properties, which must be established by extra-thermodynamic means such as experiment, theoretical calculation, or empirical estimation. While many values may be found in the numerous collected tables in the literature, these are necessarily incomplete because either the experimental measurements have not been made or the materials may be hypothetical. The current paper presents a number of simple and relible estimation methods for thermodynamic properties, principally for ionic materials. The results may also be used as a check for obvious errors in published values. The estimation methods described are typically based on addition of properties of individual ions, or sums of properties of neutral ion groups (such as “double” salts, in the Simple Salt Approximation), or based upon correlations such as with formula unit volumes (Volume-Based Thermodynamics). - Graphical abstract: Thermodynamic properties of ionic materials may be readily estimated by summation of the properties of individual ions, by summation of the properties of ‘double salts’, and by correlation with formula volume. Such estimates may fill gaps in the literature, and may also be used as checks of published values. This simplicity arises from exploitation of the fact that repulsive energy terms are of short range and very similar across materials, while coulombic interactions provide a very large component of the attractive energy in ionic systems. Display Omitted - Highlights: • Estimation methods for thermodynamic properties of ionic materials are introduced. • Methods are based on summation of single ions, multiple salts, and correlations. • Heat capacity, entropy

  6. Application of the thermodynamic-based strain gradient plasticity theory in high velocity impact problems

    Science.gov (United States)

    Voyiadjis, George; Song, Yooseob

    In this work, a thermodynamic-based framework of the higher-order strain gradient plasticity is presented to investigate the thermo-mechanical material response of the metallic volumes at extreme conditions such as high velocity impact related problems. The need of the plastic strain gradients and their corresponding rates is discussed along with the mechanism associated with geometrically necessary dislocations. One of the major issues in the strain gradient plasticity is the determination of the intrinsic material length scales that scale with the gradient of the plastic strain. Explicit and implicit microstructural length scales, which preserve the well-posed nature of the differential equations, are introduced through the use of the viscosity and gradient localization limiters. Numerical simulations of the dynamic deformation response of tantalum hat-shaped specimens, subjected to compressive loading at the ambient initial temperatures and three different strain rates, are carried out and the comparisons of the numerical results to experimental measurements are also made. Another numerical application of a blunt projectile impacting a target is examined and the direct comparison between numerical and experimental results is presented.

  7. Adsorption Thermodynamic Analysis of a Quartz Tuning Fork Based Sensor for Volatile Organic Compounds Detection.

    Science.gov (United States)

    Deng, Yue; Liu, Nai-Yuan; Tsow, Francis; Xian, Xiaojun; Forzani, Erica S

    2017-11-22

    A volatile organic compounds (VOC) sensor based on molecularly imprinted polymer (MIP) modified quartz tuning fork (QTF) has been developed. In this paper, the stability of the modified sensor as a function of the MIP composition, and the temperature effect of the analyte adsorption on the sensing transduction mechanism are evaluated. By mixing MIP and PS together, the stability was improved. A target analyte, o-xylene, was chosen as the VOC model to study the sensor response in a temperature range of 6-40 °C. Langmuir model fitted adsorption isotherms were used for thermodynamic analysis. The changes in the sensitivity of the QTF sensor to temperature rendered different behaviors. For a freshly modified QTF sensor, the adsorption response increased with increasing temperature, while for an aged QTF sensor, the adsorption response decreased with increasing temperature. The results indicated that the enthalpy change of the MIP and PS composition sensing material changes from positive to negative over the course of aging. The characterization of the reaction enabled the definition of sensor calibration conditions and stable sensor performance in field testing conditions.

  8. Extended thermodynamics

    CERN Document Server

    Müller, Ingo

    1993-01-01

    Physicists firmly believe that the differential equations of nature should be hyperbolic so as to exclude action at a distance; yet the equations of irreversible thermodynamics - those of Navier-Stokes and Fourier - are parabolic. This incompatibility between the expectation of physicists and the classical laws of thermodynamics has prompted the formulation of extended thermodynamics. After describing the motifs and early evolution of this new branch of irreversible thermodynamics, the authors apply the theory to mon-atomic gases, mixtures of gases, relativistic gases, and "gases" of phonons and photons. The discussion brings into perspective the various phenomena called second sound, such as heat propagation, propagation of shear stress and concentration, and the second sound in liquid helium. The formal mathematical structure of extended thermodynamics is exposed and the theory is shown to be fully compatible with the kinetic theory of gases. The study closes with the testing of extended thermodynamics thro...

  9. New VVV Survey Globular Cluster Candidates in the Milky Way Bulge

    Energy Technology Data Exchange (ETDEWEB)

    Minniti, Dante; Gómez, Matías [Departamento de Física, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. Fernandez Concha 700, Las Condes, Santiago (Chile); Geisler, Douglas; Fernández-Trincado, Jose G. [Departamento de Astronomía, Casilla 160-C, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Alonso-García, Javier; Beamín, Juan Carlos; Borissova, Jura; Catelan, Marcio; Ramos, Rodrigo Contreras; Kurtev, Radostin; Pullen, Joyce [Instituto Milenio de Astrofísica, Santiago (Chile); Palma, Tali; Clariá, Juan J. [Observatorio Astronómico, Universidad Nacional de Córdoba, Laprida 854, Córdoba (Argentina); Cohen, Roger E. [Space Telescope Science Institute, 2700 San Martin Drive, Baltimore (United States); Dias, Bruno [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Hempel, Maren [Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Av. Vicuña Mackenna 4860, Santiago (Chile); Ivanov, Valentin D. [European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany); Lucas, Phillip W. [Dept. of Astronomy, University of Hertfordshire, Hertfordshire (United Kingdom); Moni-Bidin, Christian; Alegría, Sebastian Ramírez [Instituto de Astronomía, Universidad Católica del Norte, Antofagasta (Chile); and others

    2017-11-10

    It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color–magnitude diagrams. We provide their coordinates as well as their near-IR color–magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color–magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A {sub Ks} < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color–magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.

  10. Unified phonon-based approach to the thermodynamics of solid, liquid and gas states

    Science.gov (United States)

    Bolmatov, Dima; Zav'yalov, Dmitry; Zhernenkov, Mikhail; Musaev, Edvard T.; Cai, Yong Q.

    2015-12-01

    We introduce a unified approach to states of matter (solid, liquid and gas) and describe the thermodynamics of the pressure-temperature phase diagram in terms of phonon excitations. We derive the effective Hamiltonian with low-energy cutoff in two transverse phonon polarizations (phononic band gaps) by breaking the symmetry in phonon interactions. Further, we construct the statistical mechanics of states of aggregation employing the Debye approximation. The introduced formalism covers the Debye theory of solids, the phonon theory of liquids, and thermodynamic limits such as the Dulong-Petit thermodynamic limit (cV = 3kB), the ideal gas limit (cV =3/2 kB) and the new thermodynamic limit (cV = 2kB), dubbed here the Frenkel line thermodynamic limit. We discuss the phonon propagation and localization effects in liquids above and below the Frenkel line, and explain the "fast sound" phenomenon. As a test for our theory we calculate velocity-velocity autocorrelation and pair distribution functions within the Green-Kubo formalism. We show the consistency between dynamics of phonons and pair correlations in the framework of the unified approach. New directions towards advancements in phononic band gaps engineering, hypersound manipulation technologies and exploration of exotic behaviour of fluids relevant to geo- and planetary sciences are discussed. The presented results are equally important both for practical implications and for fundamental research.

  11. DISCOVERY OF RR LYRAE STARS IN THE NUCLEAR BULGE OF THE MILKY WAY

    Energy Technology Data Exchange (ETDEWEB)

    Minniti, Dante; Ramos, Rodrigo Contreras; Zoccali, Manuela; Gran, Felipe [Instituto Milenio de Astrofisica, Santiago (Chile); Rejkuba, Marina; Valenti, Elena [European Southern Observatory, Karl-Schwarszchild-Str. 2, D-85748 Garching bei Muenchen (Germany); Gonzalez, Oscar A., E-mail: dante@astrofisica.cl, E-mail: rcontrer@astro.puc.cl [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)

    2016-10-10

    Galactic nuclei, such as that of the Milky Way, are extreme regions with high stellar densities, and in most cases, the hosts of a supermassive black hole. One of the scenarios proposed for the formation of the Galactic nucleus is merging of primordial globular clusters. An implication of this model is that this region should host stars that are characteristically found in old Milky Way globular clusters. RR Lyrae stars are primary distance indicators, well known representatives of old and metal-poor stellar populations, and therefore are regularly found in globular clusters. Here we report the discovery of a dozen RR Lyrae type ab stars in the vicinity of the Galactic center, i.e., in the so-called nuclear stellar bulge of the Milky Way. This discovery provides the first direct observational evidence that the Galactic nuclear stellar bulge contains ancient stars (>10 Gyr old). Based on this we conclude that merging globular clusters likely contributed to the build-up of the high stellar density in the nuclear stellar bulge of the Milky Way.

  12. Equilibrium thermodynamics

    CERN Document Server

    de Oliveira, Mário J

    2017-01-01

    This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This new edit...

  13. Thermodynamic analysis of a coal-based polygeneration system with partial gasification

    International Nuclear Information System (INIS)

    Li, Yuanyuan; Zhang, Guoqiang; Yang, Yongping; Zhai, Dailong; Zhang, Kai; Xu, Gang

    2014-01-01

    This study proposed a polygeneration system based on coal partial gasification, in which methanol and power were generated. This proposed system, comprising chemical and power islands, was designed and its characteristics are analyzed. The commercial software Aspen Plus was used to perform the system analysis. In the case study, the energy and exergy efficiency values of the proposed polygeneration system were 51.16% and 50.58%, which are 2.34% and 2.10%, respectively, higher than that of the reference system. Energy-Utilization Diagram analysis showed that removing composition adjustment and recycling 72.7% of the unreacted gas could reduce the exergy destruction during methanol synthesis by 46.85% and that the char utilized to preheat the compressed air could reduce the exergy destruction during combustion by 10.28%. Sensitivity analysis was also performed. At the same capacity ratio, the energy and exergy efficiency values of the proposed system were 1.30%–2.48% and 1.21%–2.30% higher than that of the reference system, respectively. The range of chemical-to-power capacity ratio in the proposed system was 0.41–1.40, which was narrower than that in the reference system. But the range of 1.04–1.4 was not recommended for the disappearance of energy saving potential in methanol synthesis. - Highlights: • A novel polygeneration system based on coal partial gasification is proposed. • The efficient conversion method for methanol and power is explored. • The exergy destruction in chemical energy conversion processes is decreased. • Thermodynamic performance and system characteristics are analyzed

  14. The physicochemical and thermodynamic properties of the choline chloride-based deep eutectic solvents

    Directory of Open Access Journals (Sweden)

    Troter Dragan Z.

    2017-01-01

    Full Text Available This paper reports the physicochemical (density, dynamic viscosity, electrical conductivity and refractive index and the thermodynamic (thermal expansion coefficient, molecular volume, lattice energy and heat capacity properties of several choline chloride (ChCl based deep eutectic solvents (DESs, with 1:2 mole ratio, respectively: ChCl:propylene glycol, ChCl:1,3-dimethylurea and ChCl:thiourea, at atmospheric pressure as a function of temperature over the range of 293.15–363.15 K. Their properties were also compared with those of some already characterized ChCl-based DESs, namely ChCl:ethylene glycol, ChCl:glycerol and ChCl:urea (1:2 mole ratio. Density, viscosity and refractive index of all DESs decrease with the increasing temperature while the electrical conductivity increases. Viscosity and conductivity of the tested DESs were fitted by both Arrhenius-type and Vogel–Tamman–Fulcher equations. The changes of molar enthalpy, entropy and Gibbs energy of activation, determined using the Eyring theory, demonstrated the interactional factor as predominant over the structural factor for all DES systems. The fractional Walden rule, used to correlate molar conductivity and viscosity, showed an excellent linear behaviour. It was shown that ChCl:propylene glycol DES had properties similar to ChCl:ethylene glycol and ChCl:glycerol DESs. However, the properties (density, viscosity and electrical conductivity of ChCl:1,3-dimethylurea and ChCl: :thiourea DESs were inferior to those of the ChCl:urea DES. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 45001

  15. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Osman Özkaraca

    2017-10-01

    Full Text Available Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP and its components in the aspects of thermodynamic modeling, exergy analysis and optimization processes. In-depth information is obtained about the exergy (maximum work a system can make, exergy losses and destruction at the power plant and its components. Thus the performance of the power plant may be predicted with reasonable accuracy and better understanding is gained for the physical process to be used in improving the performance of the power plant. The results of the exergy analysis show that total exergy production rate and exergy efficiency of the GPP are 21 MW and 14.52%, respectively, after removing parasitic loads. The highest amount of exergy destruction occurs, respectively, in condenser 2, vaporizer HH2, condenser 1, pumps 1 and 2 as components requiring priority performance improvement. To maximize the system exergy efficiency, the artificial bee colony (ABC is applied to the model that simulates the actual GPP. Under all the optimization conditions, the maximum exergy efficiency for the GPP and its components is obtained. Two of these conditions such as Case 4 related to the turbine and Case 12 related to the condenser have the best performance. As a result, the ABC optimization method provides better quality information than exergy analysis. Based on the guidance of this study, the performance of power plants based on geothermal energy and other energy resources may be improved.

  16. A Hamiltonian approach to Thermodynamics

    International Nuclear Information System (INIS)

    Baldiotti, M.C.; Fresneda, R.; Molina, C.

    2016-01-01

    In the present work we develop a strictly Hamiltonian approach to Thermodynamics. A thermodynamic description based on symplectic geometry is introduced, where all thermodynamic processes can be described within the framework of Analytic Mechanics. Our proposal is constructed on top of a usual symplectic manifold, where phase space is even dimensional and one has well-defined Poisson brackets. The main idea is the introduction of an extended phase space where thermodynamic equations of state are realized as constraints. We are then able to apply the canonical transformation toolkit to thermodynamic problems. Throughout this development, Dirac’s theory of constrained systems is extensively used. To illustrate the formalism, we consider paradigmatic examples, namely, the ideal, van der Waals and Clausius gases. - Highlights: • A strictly Hamiltonian approach to Thermodynamics is proposed. • Dirac’s theory of constrained systems is extensively used. • Thermodynamic equations of state are realized as constraints. • Thermodynamic potentials are related by canonical transformations.

  17. A Hamiltonian approach to Thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Baldiotti, M.C., E-mail: baldiotti@uel.br [Departamento de Física, Universidade Estadual de Londrina, 86051-990, Londrina-PR (Brazil); Fresneda, R., E-mail: rodrigo.fresneda@ufabc.edu.br [Universidade Federal do ABC, Av. dos Estados 5001, 09210-580, Santo André-SP (Brazil); Molina, C., E-mail: cmolina@usp.br [Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Av. Arlindo Bettio 1000, CEP 03828-000, São Paulo-SP (Brazil)

    2016-10-15

    In the present work we develop a strictly Hamiltonian approach to Thermodynamics. A thermodynamic description based on symplectic geometry is introduced, where all thermodynamic processes can be described within the framework of Analytic Mechanics. Our proposal is constructed on top of a usual symplectic manifold, where phase space is even dimensional and one has well-defined Poisson brackets. The main idea is the introduction of an extended phase space where thermodynamic equations of state are realized as constraints. We are then able to apply the canonical transformation toolkit to thermodynamic problems. Throughout this development, Dirac’s theory of constrained systems is extensively used. To illustrate the formalism, we consider paradigmatic examples, namely, the ideal, van der Waals and Clausius gases. - Highlights: • A strictly Hamiltonian approach to Thermodynamics is proposed. • Dirac’s theory of constrained systems is extensively used. • Thermodynamic equations of state are realized as constraints. • Thermodynamic potentials are related by canonical transformations.

  18. Application of thermodynamics-based rate-dependent constitutive models of concrete in the seismic analysis of concrete dams

    Directory of Open Access Journals (Sweden)

    Leng Fei

    2008-09-01

    Full Text Available This paper discusses the seismic analysis of concrete dams with consideration of material nonlinearity. Based on a consistent rate-dependent model and two thermodynamics-based models, two thermodynamics-based rate-dependent constitutive models were developed with consideration of the influence of the strain rate. They can describe the dynamic behavior of concrete and be applied to nonlinear seismic analysis of concrete dams taking into account the rate sensitivity of concrete. With the two models, a nonlinear analysis of the seismic response of the Koyna Gravity Dam and the Dagangshan Arch Dam was conducted. The results were compared with those of a linear elastic model and two rate-independent thermodynamics-based constitutive models, and the influences of constitutive models and strain rate on the seismic response of concrete dams were discussed. It can be concluded from the analysis that, during seismic response, the tensile stress is the control stress in the design and seismic safety evaluation of concrete dams. In different models, the plastic strain and plastic strain rate of concrete dams show a similar distribution. When the influence of the strain rate is considered, the maximum plastic strain and plastic strain rate decrease.

  19. Synthesis, thermodynamic properties and BSA interaction of a new Valen Shiff base derived from o-vanillin and trimethoprim

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xu; Jiang, Jian-Hong; Xiao, Sheng-Xiong [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan Province (China); Gu, Hui-Wen, E-mail: gruyclewee@hnu.edu.cn [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, Hunan Province (China); Li, Chuan-Hua; Ye, Li-Juan; Li, Xia; He, Du-Gui; Yao, Fei-Hong [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan Province (China); Li, Qiang-Guo, E-mail: liqiangguo@163.com [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan Province (China)

    2014-01-10

    Graphical abstract: A new single Valen Shiff base was synthesized and characterized. The thermodynamics properties of the Shiff base were investigated by microcalorimetry. In particular, the interaction between the synthetic Shiff base and BSA at four different temperatures has been investigated using fluorescence quenching method. - Highlights: • A new single Valen Shiff base was synthesized and characterized. • The thermodynamics properties of the Shiff base were investigated by microcalorimetry. • The interaction between the Shiff base and BSA has been investigated using fluorescence quenching method. - Abstract: A new Valen Shiff base (C{sub 22}H{sub 24}N{sub 4}O{sub 5}) was synthesized using equivalent moles of o-vanillin and trimethoprim. At 298.15 K, the standard molar enthalpy of formation of the new compound was estimated to be Δ{sub f}H{sub m}{sup Θ} [C{sub 22}H{sub 24}N{sub 4}O{sub 5}(s), 298.15 K] = −(696.92 ± 1.67) kJ mol{sup −1} by microcalorimetry. In particular, the interaction between the Shiff base and bovine serum albumin (BSA) has been investigated. It was proved that the fluorescence quenching of BSA by Shiff base is a result of the formation of a Shiff base-BSA complex. Quenching constants were determined using the Sterns–Volmer equation to provide a measurement of the binding site between Shiff base and BSA. The thermodynamic parameters ΔG, ΔH, and ΔS of the system at different temperatures were calculated. What is more, the distance r between donor (Trp. 213) and acceptor (Shiff base) was obtained. Finally, synchronous fluorescence spectroscopy data has suggested the association between Shiff base and BSA changed the molecular conformation of BSA.

  20. Synthesis, thermodynamic properties and BSA interaction of a new Valen Shiff base derived from o-vanillin and trimethoprim

    International Nuclear Information System (INIS)

    Li, Xu; Jiang, Jian-Hong; Xiao, Sheng-Xiong; Gu, Hui-Wen; Li, Chuan-Hua; Ye, Li-Juan; Li, Xia; He, Du-Gui; Yao, Fei-Hong; Li, Qiang-Guo

    2014-01-01

    Graphical abstract: A new single Valen Shiff base was synthesized and characterized. The thermodynamics properties of the Shiff base were investigated by microcalorimetry. In particular, the interaction between the synthetic Shiff base and BSA at four different temperatures has been investigated using fluorescence quenching method. - Highlights: • A new single Valen Shiff base was synthesized and characterized. • The thermodynamics properties of the Shiff base were investigated by microcalorimetry. • The interaction between the Shiff base and BSA has been investigated using fluorescence quenching method. - Abstract: A new Valen Shiff base (C 22 H 24 N 4 O 5 ) was synthesized using equivalent moles of o-vanillin and trimethoprim. At 298.15 K, the standard molar enthalpy of formation of the new compound was estimated to be Δ f H m Θ [C 22 H 24 N 4 O 5 (s), 298.15 K] = −(696.92 ± 1.67) kJ mol −1 by microcalorimetry. In particular, the interaction between the Shiff base and bovine serum albumin (BSA) has been investigated. It was proved that the fluorescence quenching of BSA by Shiff base is a result of the formation of a Shiff base-BSA complex. Quenching constants were determined using the Sterns–Volmer equation to provide a measurement of the binding site between Shiff base and BSA. The thermodynamic parameters ΔG, ΔH, and ΔS of the system at different temperatures were calculated. What is more, the distance r between donor (Trp. 213) and acceptor (Shiff base) was obtained. Finally, synchronous fluorescence spectroscopy data has suggested the association between Shiff base and BSA changed the molecular conformation of BSA

  1. THE X-SHAPED BULGE OF THE MILKY WAY REVEALED BY WISE

    Energy Technology Data Exchange (ETDEWEB)

    Ness, Melissa [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Lang, Dustin, E-mail: ness@mpia-hd.mpg.de [Dunlap Institute and Department of Astronomy and Astrophysics, University of Toronto, 50 Saint George Street, Toronto, ON, M5S 3H4 (Canada)

    2016-07-01

    The Milky Way bulge has a boxy/peanut morphology and an X-shaped structure. This X-shape has been revealed by the “split in the red clump” from star counts along the line of sight toward the bulge, measured from photometric surveys. This boxy, X-shaped bulge morphology is not unique to the Milky Way and such bulges are observed in other barred spiral galaxies. N -body simulations show that boxy and X-shaped bulges are formed from the disk via dynamical instabilities. It has also been proposed that the Milky Way bulge is not X-shaped, but rather, the apparent split in the red clump stars is a consequence of different stellar populations, in an old classical spheroidal bulge. We present a Wide-Field Infrared Survey Explorer ( WISE ) image of the Milky Way bulge, produced by downsampling the publicly available “unWISE” coadds. The WISE image of the Milky Way bulge shows that the X-shaped nature of the Milky Way bulge is self-evident and irrefutable. The X-shape morphology of the bulge in itself and the fraction of bulge stars that comprise orbits within this structure has important implications for the formation history of the Milky Way, and, given the ubiquity of boxy X-shaped bulges, spiral galaxies in general.

  2. General thermodynamics

    CERN Document Server

    Olander, Donald

    2007-01-01

    The book’s methodology is unified, concise, and multidisciplinary, allowing students to understand how the principles of thermodynamics apply to all technical fields that touch upon this most fundamental of scientific theories. It also offers a rigorous approach to the quantitative aspects of thermodynamics, accompanied by clear explanations to help students transition smoothly from the physical concepts to their mathematical representations

  3. Theoretical models for fluid thermodynamics based on the quasi-Gaussian entropy theory

    NARCIS (Netherlands)

    Amadei, Andrea

    1998-01-01

    Summary The theoretical modeling of fluid thermodynamics is one of the most challenging fields in physical chemistry. In fact the fluid behavior, except at very low density conditions, is still extremely difficult to be modeled from a statistical mechanical point of view, as for any realistic model

  4. Some Thermodynamics Aspects Regarding the Heating-Cooling Cycle of a SMA–Based Actuator

    Directory of Open Access Journals (Sweden)

    Alexandru Borza

    2015-12-01

    Full Text Available The goal of the paper is to prevue the conditions necessary for cooling down (from 90-95 0C to 40-45 0 C in short time the Shape Memory Alloy (SMA actuator element used in a harmonic drive. The paper analyzes the thermodynamics aspects of the heating-cooling cycle of the actuator.

  5. Investigating the Thermodynamic Performances of TO-Based Metamaterial Tunable Cells with an Entropy Generation Approach

    Directory of Open Access Journals (Sweden)

    Guoqiang Xu

    2017-10-01

    Full Text Available Active control of heat flux can be realized with transformation optics (TO thermal metamaterials. Recently, a new class of metamaterial tunable cells has been proposed, aiming to significantly reduce the difficulty of fabrication and to flexibly switch functions by employing several cells assembled on related positions following the TO design. However, owing to the integration and rotation of materials in tunable cells, they might lead to extra thermal losses as compared with the previous continuum design. This paper focuses on investigating the thermodynamic properties of tunable cells under related design parameters. The universal expression for the local entropy generation rate in such metamaterial systems is obtained considering the influence of rotation. A series of contrast schemes are established to describe the thermodynamic process and thermal energy distributions from the viewpoint of entropy analysis. Moreover, effects of design parameters on thermal dissipations and system irreversibility are investigated. In conclusion, more thermal dissipations and stronger thermodynamic processes occur in a system with larger conductivity ratios and rotation angles. This paper presents a detailed description of the thermodynamic properties of metamaterial tunable cells and provides reference for selecting appropriate design parameters on related positions to fabricate more efficient and energy-economical switchable TO devices.

  6. DFT, RHF and MP2 based study of the thermodynamic, electronic ...

    African Journals Online (AJOL)

    The thermodynamic parameters such as entropy, enthalpy, heat capacity and zero point vibrationional energy, non optical linear properties (dipole moment and mean polarizability) and Mullikan charges were calculated using Restricted Hartree–Fock (RHF), Moller-Plesset Second Order Perturbation Theory (MP2) and ...

  7. Numerical Predictions of Damage and Failure in Carbon Fiber Reinforced Laminates Using a Thermodynamically-Based Work Potential Theory

    Science.gov (United States)

    Pineda, Evan Jorge; Waas, Anthony M.

    2013-01-01

    A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, referred to as enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Consistent characteristic lengths are introduced into the formulation to govern the evolution of the failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs are derived. The theory is implemented into a commercial finite element code. The model is verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared against the experimental results.

  8. Ongoing massive star formation in the bulge of M51

    NARCIS (Netherlands)

    Lamers, HJGLM; Panagia, N; Scuderi, S; Romaniello, M; Spaans, M; Kirshner, R

    2002-01-01

    We present a study of Hubble Space Telescope Wide Field Planetary Camera 2 observations of the inner kiloparsec of the interacting galaxy M51 in six bands from 2550 to 8140 Angstrom. The images show an oval-shaped area (which we call the "bulge") of about 11" x 16", or 450 x 650 pc, around the

  9. COLORS AND COLOR GRADIENTS IN BULGES OF GALAXIES

    NARCIS (Netherlands)

    BALCELLS, M; PELETIER, RF

    We have obtained surface photometry in U, B, R, and I for a complete optically selected sample of 45 early-type spiral galaxies, to investigate the colors and color gradients of spiral bulges. Color profiles in U-R, B-R, U-B, and R-I have been determined in wedges opening on the semiminor axes.

  10. THE BULGE OF M-104 - STELLAR CONTENT AND KINEMATICS

    NARCIS (Netherlands)

    HES, R; PELETIER, RF

    Optical and near-infrared surface photometry of the bulge of M 104, the Sombrero Galaxy, is presented. From these data we have determined the radial variations of colours along the minor axis. We also present absorption line strength gradients of a number of metal lines and molecular bands. The

  11. Observational constraints to boxy/peanut bulge formation time

    NARCIS (Netherlands)

    Pérez, I.; Martínez-Valpuesta, I.; Ruiz-Lara, T.; de Lorenzo-Caceres, A.; Falcón-Barroso, J.; Florido, E.; González Delgado, R. M.; Lyubenova, M.; Marino, R. A.; Sánchez, S. F.; Sánchez-Blázquez, P.; van de Ven, G.; Zurita, A.

    2017-01-01

    Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this Letter is to determine if the mass assembly of the different components leaves an imprint in their

  12. Distinguishing ventricular septal bulge versus hypertrophic cardiomyopathy in the elderly.

    Science.gov (United States)

    Canepa, Marco; Pozios, Iraklis; Vianello, Pier Filippo; Ameri, Pietro; Brunelli, Claudio; Ferrucci, Luigi; Abraham, Theodore P

    2016-07-15

    The burgeoning evidence of patients diagnosed with sigmoidal hypertrophic cardiomyopathy (HCM) later in life has revived the quest for distinctive features that may help discriminate it from more benign forms of isolated septal hypertrophy often labelled ventricular septal bulge (VSB). HCM is diagnosed less frequently than VSB at older ages, with a reversed female predominance. Most patients diagnosed with HCM at older ages suffer from hypertension, similar to those with VSB. A positive family history of HCM and/or sudden cardiac death and the presence of exertional symptoms usually support HCM, though they are less likely in older patients with HCM, and poorly investigated in individuals with VSB. A more severe hypertrophy and the presence of left ventricular outflow obstruction are considered diagnostic of HCM, though stress echocardiography has not been consistently used in VSB. Mitral annulus calcification is very prevalent in both conditions, whereas a restrictive filling pattern is found in a minority of older patients with HCM. Genetic testing has low applicability in this differential diagnosis at the current time, given that a causative mutation is found in less than 10% of elderly patients with suspected HCM. Emerging imaging modalities that allow non-invasive detection of myocardial fibrosis and disarray may help, but have not been fully investigated. Nonetheless, there remains a considerable morphological overlap between the two conditions. Comprehensive studies, particularly imaging based, are warranted to offer a more evidence-based approach to elderly patients with focal septal thickening. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  13. Advanced thermodynamics engineering

    CERN Document Server

    Annamalai, Kalyan; Jog, Milind A

    2011-01-01

    Thermolab Excel-Based Software for Thermodynamic Properties and Flame Temperatures of Fuels IntroductionImportance, Significance and LimitationsReview of ThermodynamicsMathematical BackgroundOverview of Microscopic/NanothermodynamicsSummaryAppendix: Stokes and Gauss Theorems First Law of ThermodynamicsZeroth LawFirst Law for a Closed SystemQuasi Equilibrium (QE) and Nonquasi-equilibrium (NQE) ProcessesEnthalpy and First LawAdiabatic Reversible Process for Ideal Gas with Constant Specific HeatsFirst Law for an Open SystemApplications of First Law for an Open SystemIntegral and Differential Form

  14. Experimental investigation and thermodynamic modeling of molybdenum and vanadium-containing carbide hardened iron-based alloys

    International Nuclear Information System (INIS)

    Cabrol, E.; Bellot, C.; Lamesle, P.; Delagnes, D.; Povoden-Karadeniz, E.

    2013-01-01

    Highlights: ► Improvement of a carbide selective extraction method. ► Determination of experimental data on the Fe–C–Cr–Mo–V system for carbides above 900 °C: crystallographic structures and compositions of precipitates, matrix composition. ► High molybdenum solubility in FCC carbides. ► Improvement of thermodynamic databases from experimental results. ► Validation of the optimized database with different compositions steels. -- Abstract: A technique for the microstructural study of steels, based on the use of matrix dissolution to collect the very low number density precipitates formed in martensitic steels, has been considerably improved. This technique was applied to two different grades of alloy, characterized by high nickel and cobalt contents and varying chromium, molybdenum and vanadium contents. The technique was implemented at temperatures ranging between 900 °C and 1000 °C, in order to accurately determine experimental data including the crystallographic structure and chemical composition of the carbides, the carbide solvus temperatures, and variations in the chemical composition of the matrix. These experimental investigations reveal that the solubility of molybdenum in FCC carbides can be very high. These results have been compared with the behavior predicted by computational thermodynamics, and used to evaluate and improve the thermodynamic Matcalc steel database. This upgraded database has been validated on three other steels with different chemical compositions, characterized by the same Fe–Cr–Mo–V–C system

  15. On the thermodynamic efficiency of a nickel-based multiferroic thermomagnetic generator: From bulk to atomic scale

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, Samuel M., E-mail: samuel.m.sandoval@gmail.com; Sepulveda, Abdon E., E-mail: abdon.sepulveda@gmail.com; Keller, Scott M., E-mail: smkeller@ucla.edu [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095 (United States)

    2015-04-28

    A model is developed to correlate the effects of size on the thermodynamic efficiency for a nickel-based multiferroic thermomagnetic generator device. Three existing models are combined in order to estimate this correlation, they are (1) thermodynamic efficiency relations, (2) a model of ferromagnetic transition behavior, and (3) the bond-order length strength correlation. At the smallest size considered, a monolayer of nickel atoms shows a reduction in Curie temperature from its bulk value of T{sub c,Bulk}=630 K to T{sub c,ML}=240 K. This difference is analytically shown to affect the thermodynamic efficiency values when compared to bulk. Various nickel nanofilms are considered as a working body, such that the combined model predicts relative efficiency values that are comparable to the bulk scale, but operating closer to room-temperature when compared to bulk form. This result is unexpected since the absolute efficiency is shown to increase as a function of decreasing size, this discrepancy is explained as a consequence of Curie point suppression. The combined model is also applied to a hypothetical composite made of separated layers of nickel with distinct thicknesses. This composite material is predicted to spread the ferromagnetic transition across a much larger temperature range as compared to bulk nickel, such that this material may be better suited for different applications; for example, as a sensor or thermal switch. Moreover, this combined model is also shown to give a lower-bound estimate for thermodynamic efficiency, since the actual performance depends on material characterizations that have yet to be determined.

  16. Thermodynamic analysis of a novel tri-generation system based on compressed air energy storage and pneumatic motor

    International Nuclear Information System (INIS)

    Liu, Jin-Long; Wang, Jian-Hua

    2015-01-01

    Based on CAES (compressed air energy storage) and PM (pneumatic motor), a novel tri-generation system (heat energy, mechanical energy and cooling power) is proposed in this paper. Both the cheap electricity generated at night and the excess power from undelivered renewable energy due to instability, can be stored as compressed air and hot water by the proposed system. When energy is in great demand, the compressed air stored in this system is released to drive PM to generate mechanical power. The discharged air from PM can be further utilized as valuable cooling power. Compared to conventional CAES systems, the biggest characteristic of the proposed system is that the discharged air usually abandoned is used as cooling power. In order to study the performances of this system, a thermodynamic analysis and an experimental investigation are carried out. The thermodynamic model is validated by the experimental data. Using the validated thermodynamic model, the mechanical energy output, cooling capacity and temperature of discharged air, as well as the efficiency of the system are analyzed. The theoretical analysis indicates that the additional application of discharged air can improve total energy efficiency by 20–30%. Therefore, this system is very worthy of consideration and being popularized. - Highlights: • The proposed system can provide mechanical energy, heat energy and cooling power. • The exhaust air of pneumatic motor is used as cooling power instead of abandoned. • A thermodynamic model of the proposed system is constructed and validated. • The effects of several parameters on system performance are examined. • The proposed system can improve total energy efficiency of CAES system by 20–30%.

  17. Thermodynamic holography.

    Science.gov (United States)

    Wei, Bo-Bo; Jiang, Zhan-Feng; Liu, Ren-Bao

    2015-10-19

    The holographic principle states that the information about a volume of a system is encoded on the boundary surface of the volume. Holography appears in many branches of physics, such as optics, electromagnetism, many-body physics, quantum gravity, and string theory. Here we show that holography is also an underlying principle in thermodynamics, a most important foundation of physics. The thermodynamics of a system is fully determined by its partition function. We prove that the partition function of a finite but arbitrarily large system is an analytic function on the complex plane of physical parameters, and therefore the partition function in a region on the complex plane is uniquely determined by its values along the boundary. The thermodynamic holography has applications in studying thermodynamics of nano-scale systems (such as molecule engines, nano-generators and macromolecules) and provides a new approach to many-body physics.

  18. Green thermodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Cengel, Y.A. [Nevada Univ., Reno, NV (United States). Dept. of Mechanical Engineering

    2006-07-01

    Green components of thermodynamics were identified and general aspects of green practices associated with thermodynamics were assessed. Energy uses associated with fossil fuels were reviewed. Green energy sources such as solar, wind, geothermal and hydropower were discussed, as well as biomass plantations. Ethanol production practices were reviewed. Conservation practices in the United States were outlined. Energy efficiency and exergy analyses were discussed. Energy intensity measurements and insulation products for houses were also reviewed. Five case studies were presented to illustrate aspects of green thermodynamics: (1) light in a classroom; (2) fuel saved by low-resistance tires; and (3) savings with high-efficiency motors; (4) renewable energy; and (5) replacing a valve with a turbine at a cryogenic manufacturing facility. It was concluded that the main principles of green thermodynamics are to ensure that all material and energy inputs minimize the depletion of energy resources; prevent waste; and improve or innovate technologies that achieve sustainability. 17 refs., 2 tabs., 9 figs.

  19. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  20. Thermodynamic holography

    Science.gov (United States)

    Wei, Bo-Bo; Jiang, Zhan-Feng; Liu, Ren-Bao

    2015-01-01

    The holographic principle states that the information about a volume of a system is encoded on the boundary surface of the volume. Holography appears in many branches of physics, such as optics, electromagnetism, many-body physics, quantum gravity, and string theory. Here we show that holography is also an underlying principle in thermodynamics, a most important foundation of physics. The thermodynamics of a system is fully determined by its partition function. We prove that the partition function of a finite but arbitrarily large system is an analytic function on the complex plane of physical parameters, and therefore the partition function in a region on the complex plane is uniquely determined by its values along the boundary. The thermodynamic holography has applications in studying thermodynamics of nano-scale systems (such as molecule engines, nano-generators and macromolecules) and provides a new approach to many-body physics. PMID:26478214

  1. Thermodynamic analysis of a dual power-hydrogen production system based on chemical-looping combustion

    OpenAIRE

    Urdiales, Álvaro; Jiménez Alvaro, Ángel; Sánchez Orgaz, Susana; González Fernández, M. Celina

    2016-01-01

    Chemical-looping hydrogen generation (CLHG) is a chemical-looping combustion variant that allows simultaneous production of power and hydrogen. A thermodynamic analysis from the exergy method point of view of an integrated syngas-fueled CLHG cycle is carried out with the aim of contributing to the conceptual understanding and development of CLHG systems. The cycle working point is optimized in a range of conditions. The proposed system shows a very interesting potential for power, hydrogen an...

  2. Kinetic and thermodynamic bases to resolve issues regarding conditioning of uranium metal fuels

    International Nuclear Information System (INIS)

    Johnson, A.B.; Ballinger, R.G.; Simpson, K.A.

    1994-12-01

    Numerous uranium - bearing fuels are corroding in fuel storage pools in several countries. At facilities where reprocessing is no longer available, dry storage is being evaluated to preclude aqueous corrosion that is ongoing. It is essential that thermodynamic and kinetic factors are accounted for in transitions of corroding uranium-bearing fuels to dry storage. This paper addresses a process that has been proposed to move Hanford N-Reactor fuel from wet storage to dry storage

  3. Exergy-based thermodynamic analysis of solar driven Organic Rankine Cycle

    OpenAIRE

    kerme, Esa; Orfi, Jamel

    2015-01-01

    In this paper thermodynamic modeling of organic Rankine cycle (ORC) driven by parabolic trough solar collectors is presented. Eight working fluids for the ORC were examined. The effect of turbine inlet temperature on main energetic and exergetic performance parameters were studied. The influences of turbine inlet temperature on turbine size parameter, turbine outlet volume flow rate and expansion ratio were also investigated. Important exergetic parameters including irreversibility ratio and ...

  4. Thermodynamic Stability of Structure H Hydrates Based on the Molecular Properties of Large Guest Molecules

    OpenAIRE

    Kyoichi Tezuka; Tatsuhiko Taguchi; Saman Alavi; Amadeu K. Sum; Ryo Ohmura

    2012-01-01

    This paper report analyses of thermodynamic stability of structure-H clathrate hydrates formed with methane and large guest molecules in terms of their gas phase molecular sizes and molar masses for the selection of a large guest molecule providing better hydrate stability. We investigated the correlation among the gas phase molecular sizes, the molar masses of large molecule guest substances, and the equilibrium pressures. The results suggest that there exists a molecular-size value for the ...

  5. Practical thermodynamic quantities for aqueous vanadium- and iron-based flow batteries

    Science.gov (United States)

    Hudak, Nicholas S.

    2014-12-01

    A simple method for experimentally determining thermodynamic quantities for flow battery cell reactions is presented. Equilibrium cell potentials, temperature derivatives of cell potential (dE/dT), Gibbs free energies, and entropies are reported here for all-vanadium, iron-vanadium, and iron-chromium flow cells with state-of-the-art solution compositions. Proof is given that formal potentials and formal temperature coefficients can be used with modified forms of the Nernst Equation to quantify the thermodynamics of flow cell reactions as a function of state-of-charge. Such empirical quantities can be used in thermo-electrochemical models of flow batteries at the cell or system level. In most cases, the thermodynamic quantities measured here are significantly different from standard values reported and used previously in the literature. The data reported here are also useful in the selection of operating temperatures for flow battery systems. Because higher temperatures correspond to lower equilibrium cell potentials for the battery chemistries studied here, it can be beneficial to charge a cell at higher temperature and discharge at lower temperature. Proof-of-concept of improved voltage efficiency with the use of such non-isothermal cycling is given for the all-vanadium redox flow battery, and the effect is shown to be more pronounced at lower current densities.

  6. Correlation between structural and thermodynamic properties of some selenium based phase-change materials

    Science.gov (United States)

    Chandel, Namrata; Mehta, Neeraj

    2018-04-01

    In this study, we prepared novel selenium rich multi-component glasses by incorporating In, Cd and Sb as foreign elements in an Sn containing Sesbnd Te system in order to study their metal-induced effects on the thermal properties of the parent ternary glass. In particular, we determined the thermodynamic parameters of Se80Te18Sn2 and Se80Te8Sn2M10 (M = Cd, In, Sb) glassy semiconductors in a non-isothermal environment using the differential scanning calorimetry. Calorimetric measurements were obtained in the glass transition regions for Se80Te18Sn2 and Se80Te8Sn2M10 (M = Cd, In, Sb) glasses to determine their thermodynamic parameters such as the specific heat, enthalpy, and entropy during glass transition. We analyzed the variation in the specific heat before and after the heat capacity jump in these alloys. The metal-induced effects of foreign elements on the thermodynamic properties of the parent glass were also investigated in terms of the influence of the elemental specific heat of the added elemental metal as well as the thermal stability and glass-forming ability of the glasses.

  7. The metallicity distribution of stars in the Galactic bulge and disc

    Science.gov (United States)

    Koeppen, J.; Arimoto, N.

    1989-06-01

    The chemical evolution of the three-component system of halo-bulge-disc is calculated. If the bulge accretes primordial halo matter quickly and forms stars rapidly before the gas is ejected by a galactic wind after 10 to the 9th yr, the metallicity distribution of the bulge K-giants (Rich, 1988) is reproduced. The metal-enriched matter in a wind from the bulge is mixed with the halo gas which is accreted into the disc. The metallicity distribution of the G-dwarfs and Twarog's (1980) age-metallicity relation in the solar neighborhood can be well reproduced by assuming reasonable bulge-to-disc mass ratio.

  8. Mathematical Model Based on Newton’s Laws and in First Thermodynamic Law of a Gas Turbine

    OpenAIRE

    Ottmar Rafael Uriza Gosebruch; Carlos Alexander Nuñez Martin; Eloy Edmundo Rodríguez Vázquez; Eduardo Campos Mercado

    2017-01-01

    The present article explains the modeling of a Gas Turbine system; the mathematical modeling is based on fluid mechanics applying the principal energy laws such as Euler’s Law, Newton’s second Law and the first thermodynamic law to obtain the equations for mass, momentum and energy conservation; expressed as the continuity equation, the Navier-Stokes equation and the energy conservation using Fourier’s Law. The purpose of this article is to establish a precise mathematical model to be applied...

  9. Mathematical Model Based on Newton’s Laws and in First Thermodynamic Law of a Gas Turbine

    Directory of Open Access Journals (Sweden)

    Ottmar Rafael Uriza Gosebruch

    2017-09-01

    Full Text Available The present article explains the modeling of a Gas Turbine system; the mathematical modeling is based on fluid mechanics applying the principal energy laws such as Euler’s Law, Newton’s second Law and the first thermodynamic law to obtain the equations for mass, momentum and energy conservation; expressed as the continuity equation, the Navier-Stokes equation and the energy conservation using Fourier’s Law. The purpose of this article is to establish a precise mathematical model to be applied in control applications, for future works, within industry applications.

  10. Thermodynamic-based retention time predictions of endogenous steroids in comprehensive two-dimensional gas chromatography.

    Science.gov (United States)

    Silva, Aline C A; Ebrahimi-Najafadabi, Heshmatollah; McGinitie, Teague M; Casilli, Alessandro; Pereira, Henrique M G; Aquino Neto, Francisco R; Harynuk, James J

    2015-05-01

    This work evaluates the application of a thermodynamic model to comprehensive two-dimensional gas chromatography (GC × GC) coupled with time-of-flight mass spectrometry for anabolic agent investigation. Doping control deals with hundreds of drugs that are prohibited in sports. Drug discovery in biological matrices is a challenging task that requires powerful tools when one is faced with the rapidly changing designer drug landscape. In this work, a thermodynamic model developed for the prediction of both primary and secondary retention times in GC × GC has been applied to trimethylsilylated hydroxyl (O-TMS)- and methoxime-trimethylsilylated carbonyl (MO-TMS)-derivatized endogenous steroids. This model was previously demonstrated on a pneumatically modulated GC × GC system, and is applied for the first time to a thermally modulated GC × GC system. Preliminary one-dimensional experiments allowed the calculation of thermodynamic parameters (ΔH, ΔS, and ΔC p ) which were successfully applied for the prediction of the analytes' interactions with the stationary phases of both the first-dimension column and the second-dimension column. The model was able to predict both first-dimension and second-dimension retention times with high accuracy compared with the GC × GC experimental measurements. Maximum differences of -8.22 s in the first dimension and 0.4 s in the second dimension were encountered for the O-TMS derivatives of 11β-hydroxyandrosterone and 11-ketoetiocholanolone, respectively. For the MO-TMS derivatives, the largest discrepancies were from testosterone (9.65 ) for the first-dimension retention times and 11-keto-etiocholanolone (0.4 s) for the second-dimension retention times.

  11. Bulging of cans containing plutonium residues. Summary report

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Wood, D.H.; Condit, R.H.; Shikany, S.D.

    1996-03-01

    In 1994, two cans in the Lawrence Livermore National Laboratory Plutonium Facility were found to be bulging as a result of the generation of gases form the plutonium ash residues contained in the cans. This report describes the chronology of this discovery, the response actions that revealed other pressurized cans, the analysis of the causes, the short-term remedial action, a followup inspection of the short-term storage packages, and a review of proposed long-term remedial options

  12. Alpha-Bulges in G Protein-Coupled Receptors

    Directory of Open Access Journals (Sweden)

    Rob van der Kant

    2014-05-01

    Full Text Available Agonist binding is related to a series of motions in G protein-coupled receptors (GPCRs that result in the separation of transmembrane helices III and VI at their cytosolic ends and subsequent G protein binding. A large number of smaller motions also seem to be associated with activation. Most helices in GPCRs are highly irregular and often contain kinks, with extensive literature already available about the role of prolines in kink formation and the precise function of these kinks. GPCR transmembrane helices also contain many α-bulges. In this article we aim to draw attention to the role of these α-bulges in ligand and G-protein binding, as well as their role in several aspects of the mobility associated with GPCR activation. This mobility includes regularization and translation of helix III in the extracellular direction, a rotation of the entire helix VI, an inward movement of the helices near the extracellular side, and a concerted motion of the cytosolic ends of the helices that makes their orientation appear more circular and that opens up space for the G protein to bind. In several cases, α-bulges either appear or disappear as part of the activation process.

  13. Modern thermodynamics

    CERN Document Server

    Ben-Naim, Arieh

    2017-01-01

    This textbook introduces thermodynamics with a modern approach, starting from four fundamental physical facts (the atomic nature of matter, the indistinguishability of atoms and molecules of the same species, the uncertainty principle, and the existence of equilibrium states) and analyzing the behavior of complex systems with the tools of information theory, in particular with Shannon's measure of information (or SMI), which can be defined on any probability distribution. SMI is defined and its properties and time evolution are illustrated, and it is shown that the entropy is a particular type of SMI, i.e. the SMI related to the phase-space distribution for a macroscopic system at equilibrium. The connection to SMI allows the reader to understand what entropy is and why isolated systems follow the Second Law of Thermodynamics. The Second Llaw is also formulated for other systems, not thermally isolated and even open with respect to the transfer of particles. All the fundamental aspects of thermodynamics are d...

  14. Physicochemical Characterization and Thermodynamic Studies of Nanoemulsion-Based Transdermal Delivery System for Fullerene

    Directory of Open Access Journals (Sweden)

    Cheng Loong Ngan

    2014-01-01

    Full Text Available Fullerene nanoemulsions were formulated in palm kernel oil esters stabilized by low amount of mixed nonionic surfactants. Pseudoternary phase diagrams were established in the colloidal system of PKOEs/Tween 80 : Span 80/water incorporated with fullerene as antioxidant. Preformulation was subjected to combination of high and low energy emulsification methods and the physicochemical characteristics of fullerene nanoemulsions were analyzed using electroacoustic spectrometer. Oil-in-water (O/W nanoemulsions with particle sizes in the range of 70–160 nm were formed. The rheological characteristics of colloidal systems exhibited shear thinning behavior which fitted well into the power law model. The effect of xanthan gum (0.2–1.0%, w/w and beeswax (1–3%, w/w in the estimation of thermodynamics was further studied. From the energetic parameters calculated for the viscous flow, a moderate energy barrier for transport process was observed. Thermodynamic study showed that the enthalpy was positive in all xanthan gum and beeswax concentrations indicating that the formation of nanoemulsions could be endothermic in nature. Fullerene nanoemulsions with 0.6% or higher xanthan gum content were found to be stable against creaming and flocculation when exposed to extreme environmental conditions.

  15. Physicochemical Characterization and Thermodynamic Studies of Nanoemulsion-Based Transdermal Delivery System for Fullerene

    Science.gov (United States)

    Basri, Mahiran; Tripathy, Minaketan; Abdul-Malek, Emilia

    2014-01-01

    Fullerene nanoemulsions were formulated in palm kernel oil esters stabilized by low amount of mixed nonionic surfactants. Pseudoternary phase diagrams were established in the colloidal system of PKOEs/Tween 80 : Span 80/water incorporated with fullerene as antioxidant. Preformulation was subjected to combination of high and low energy emulsification methods and the physicochemical characteristics of fullerene nanoemulsions were analyzed using electroacoustic spectrometer. Oil-in-water (O/W) nanoemulsions with particle sizes in the range of 70–160 nm were formed. The rheological characteristics of colloidal systems exhibited shear thinning behavior which fitted well into the power law model. The effect of xanthan gum (0.2–1.0%, w/w) and beeswax (1–3%, w/w) in the estimation of thermodynamics was further studied. From the energetic parameters calculated for the viscous flow, a moderate energy barrier for transport process was observed. Thermodynamic study showed that the enthalpy was positive in all xanthan gum and beeswax concentrations indicating that the formation of nanoemulsions could be endothermic in nature. Fullerene nanoemulsions with 0.6% or higher xanthan gum content were found to be stable against creaming and flocculation when exposed to extreme environmental conditions. PMID:25165736

  16. Atomistic modeling of thermodynamic properties of Pu-Ga alloys based on the Invar mechanism

    Science.gov (United States)

    Lee, Tongsik; Taylor, Christopher D.; Lawson, A. C.; Conradson, Steven D.; Chen, Shao Ping; Caro, A.; Valone, Steven M.; Baskes, Michael I.

    2014-05-01

    We present an atomistic model that accounts for a range of anomalous thermodynamic properties of the fcc δ phase of Pu-Ga alloys in terms of the Invar mechanism. Two modified embedded atom method potentials are employed to represent competing electronic states in δ-Pu, each of which has an individual configuration dependence as well as distinct interactions with gallium. Using classical Monte Carlo simulations, we compute the temperature dependence of various thermodynamic properties for different dilute gallium concentrations. The model reproduces the observed effects of excessive volume reduction along with a rapid shift in thermal expansion from negative to positive values with increasing gallium concentration. It also predicts progressive stiffening upon dilute-gallium alloying, while the calculated thermal softening is nearly independent of the gallium concentration in agreement with resonant ultrasound spectroscopy measurements in the literature. Analysis of the local structure predicted by the model indicates that the distribution of the gallium atoms is not completely random in the δ phase due to the presence of short-range order associated with the Invar mechanism. This effect is consistent with the nanoscale heterogeneity in local gallium concentration which is observed in recent extended x-ray absorption fine structure spectroscopy experiments. Implications of the Invar effect for phase stability and physical interpretations of the two states are also discussed.

  17. The Bases of Chemical Thermodynamics, Volumes 1 and 2 by Michael Graetzel and Pierre Infelta

    Science.gov (United States)

    van Hecke, Gerald R.

    2001-09-01

    Universal Publishers: Parkland, FL, 2000. Vol. 1: 298 pp. ISBN 1-58112-772-3. 25.95. Vol. 2: 300 pp. ISBN 1-58112-771-5. 25.95. Rarely does one pick up a text and find in it so many of one's favorite pedagogical devices. Graetzel and Infelta was a treat to read. The text offers many new and clever derivations of the well-worn equations of chemical thermodynamics and for this reason alone the text should be on the bookshelf of every serious teacher of thermodynamics. The writing is easy to read: not terse, but carefully worded as a thermodynamics text should be. There are no fancy sidebars or tidbits, just a straightforward presentation of material that is frankly refreshing. A brief description of the text should come next, for it consist of two volumes. You find in Volume 1 introductory material, the laws of thermodynamics, auxiliary functions, molar and partial molar quantities, gases, and component phase equilibria; in Volume 2, the energetics of chemical reactions, chemical equilibria, properties of ideal and nonideal mixtures, and an introduction to statistical mechanics. The authors make careful definitions of those slippery concepts, systems, states, and extensive and intensive variables, and use those definitions to show how the thermodynamic state of a system can be described in a minimum number of variables. A pedagogical feature that makes a hit with me is the authors' disuse of deltas. They explicitly write Ufinal - Uinitial instead of just good old DU, which really tells a reader nothing. How much better our students would understand thermodynamics if we were to ban D 's remains to be seen. The authors are consistent in their disuse of D 's except for standard expressions such as DrG°. Entropy, every beginning student's random nightmare, is introduced by the concept of arrangements available to the system. The number of arrangements can be quantified by various permutation formulas. Thank the authors for sticking with arrangements that can be

  18. A Laser Induced Breakdown Spectroscopy application based on Local Thermodynamic Equilibrium assumption for the elemental analysis of alexandrite gemstone and copper-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    De Giacomo, A. [Department of Chemistry, University of Bari, Via Orabona 4, 70126 Bari (Italy); Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Dell' Aglio, M. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Gaudiuso, R., E-mail: rosalba.gaudiuso@ba.imip.cnr.it [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Santagata, A. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Potenza, Via S. Loja, Zona Ind., 85050 Tito Scalo (PZ) (Italy); Senesi, G.S. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy); Rossi, M.; Ghiara, M.R. [Department of Earth Sciences, University of Naples ' Federico II' , Via Mezzocannone 8, 80134 Naples (Italy); Capitelli, F. [Institute of Crystallography - CNR, Via Salaria Km 29.300, 00015 Monterotondo (Roma) (Italy); De Pascale, O. [Institute of Inorganic Methodologies and Plasmas - CNR, U.O.S. Bari, Via Amendola 122/D, 70126 Bari (Italy)

    2012-04-04

    Graphical abstract: Self-calibrated analytical techniques based on the approximation of Local Thermodynamic Equilibrium (LTE) have been employed for the analysis of gemstones and copper-based alloys by LIBS (Laser Induced Breakdown Spectroscopy), with a special focus on LTE conditions in laser induced plasmas. Highlights: Black-Right-Pointing-Pointer Discussion of Local Thermodynamic Equilibrium (LTE) condition in laser-induced plasmas. Black-Right-Pointing-Pointer LIBS enables elemental analysis with self-calibrated LTE-based methods. Black-Right-Pointing-Pointer Be detection in alexandrite gemstone is made possible by LIBS. - Abstract: Laser Induced Breakdown Spectroscopy (LIBS) is an appealing technique to study laser-induced plasmas (LIPs), both from the basic diagnostics point of view and for analytical applications. LIPs are complex dynamic systems, expanding at supersonic velocities and undergoing a transition between different plasma regimes. If the Local Thermodynamic Equilibrium (LTE) condition is valid for such plasmas, several analytical methods can be employed and fast quantitative analyses can be performed on a variety of samples. In the present paper, a discussion about LTE is carried out and an innovative application to the analysis of the alexandrite gemstone is presented. In addition, a study about the influence of plasma parameters on the performance of LTE-based methods is reported for bronze and brass targets.

  19. A Laser Induced Breakdown Spectroscopy application based on Local Thermodynamic Equilibrium assumption for the elemental analysis of alexandrite gemstone and copper-based alloys

    International Nuclear Information System (INIS)

    De Giacomo, A.; Dell’Aglio, M.; Gaudiuso, R.; Santagata, A.; Senesi, G.S.; Rossi, M.; Ghiara, M.R.; Capitelli, F.; De Pascale, O.

    2012-01-01

    Graphical abstract: Self-calibrated analytical techniques based on the approximation of Local Thermodynamic Equilibrium (LTE) have been employed for the analysis of gemstones and copper-based alloys by LIBS (Laser Induced Breakdown Spectroscopy), with a special focus on LTE conditions in laser induced plasmas. Highlights: ► Discussion of Local Thermodynamic Equilibrium (LTE) condition in laser-induced plasmas. ► LIBS enables elemental analysis with self-calibrated LTE-based methods. ► Be detection in alexandrite gemstone is made possible by LIBS. - Abstract: Laser Induced Breakdown Spectroscopy (LIBS) is an appealing technique to study laser-induced plasmas (LIPs), both from the basic diagnostics point of view and for analytical applications. LIPs are complex dynamic systems, expanding at supersonic velocities and undergoing a transition between different plasma regimes. If the Local Thermodynamic Equilibrium (LTE) condition is valid for such plasmas, several analytical methods can be employed and fast quantitative analyses can be performed on a variety of samples. In the present paper, a discussion about LTE is carried out and an innovative application to the analysis of the alexandrite gemstone is presented. In addition, a study about the influence of plasma parameters on the performance of LTE-based methods is reported for bronze and brass targets.

  20. The Age of the Young Bulge-like Population in the Stellar System Terzan 5: Linking the Galactic Bulge to the High-z Universe

    NARCIS (Netherlands)

    Ferraro, F. R.; Massari, D.; Dalessandro, E.; Lanzoni, B.; Origlia, L.; Rich, R. M.; Mucciarelli, A.

    2016-01-01

    The Galactic bulge is dominated by an old, metal-rich stellar population. The possible presence and the amount of a young (a few gigayears old) minor component is one of the major issues debated in the literature. Recently, the bulge stellar system Terzan 5 was found to harbor three sub-populations

  1. Bioenergetics-based modeling of Plasmodium falciparum metabolism reveals its essential genes, nutritional requirements, and thermodynamic bottlenecks.

    Directory of Open Access Journals (Sweden)

    Anush Chiappino-Pepe

    2017-03-01

    Full Text Available Novel antimalarial therapies are urgently needed for the fight against drug-resistant parasites. The metabolism of malaria parasites in infected cells is an attractive source of drug targets but is rather complex. Computational methods can handle this complexity and allow integrative analyses of cell metabolism. In this study, we present a genome-scale metabolic model (iPfa of the deadliest malaria parasite, Plasmodium falciparum, and its thermodynamics-based flux analysis (TFA. Using previous absolute concentration data of the intraerythrocytic parasite, we applied TFA to iPfa and predicted up to 63 essential genes and 26 essential pairs of genes. Of the 63 genes, 35 have been experimentally validated and reported in the literature, and 28 have not been experimentally tested and include previously hypothesized or novel predictions of essential metabolic capabilities. Without metabolomics data, four of the genes would have been incorrectly predicted to be non-essential. TFA also indicated that substrate channeling should exist in two metabolic pathways to ensure the thermodynamic feasibility of the flux. Finally, analysis of the metabolic capabilities of P. falciparum led to the identification of both the minimal nutritional requirements and the genes that can become indispensable upon substrate inaccessibility. This model provides novel insight into the metabolic needs and capabilities of the malaria parasite and highlights metabolites and pathways that should be measured and characterized to identify potential thermodynamic bottlenecks and substrate channeling. The hypotheses presented seek to guide experimental studies to facilitate a better understanding of the parasite metabolism and the identification of targets for more efficient intervention.

  2. Bioenergetics-based modeling of Plasmodium falciparum metabolism reveals its essential genes, nutritional requirements, and thermodynamic bottlenecks

    Science.gov (United States)

    Chiappino-Pepe, Anush; Ataman, Meriç

    2017-01-01

    Novel antimalarial therapies are urgently needed for the fight against drug-resistant parasites. The metabolism of malaria parasites in infected cells is an attractive source of drug targets but is rather complex. Computational methods can handle this complexity and allow integrative analyses of cell metabolism. In this study, we present a genome-scale metabolic model (iPfa) of the deadliest malaria parasite, Plasmodium falciparum, and its thermodynamics-based flux analysis (TFA). Using previous absolute concentration data of the intraerythrocytic parasite, we applied TFA to iPfa and predicted up to 63 essential genes and 26 essential pairs of genes. Of the 63 genes, 35 have been experimentally validated and reported in the literature, and 28 have not been experimentally tested and include previously hypothesized or novel predictions of essential metabolic capabilities. Without metabolomics data, four of the genes would have been incorrectly predicted to be non-essential. TFA also indicated that substrate channeling should exist in two metabolic pathways to ensure the thermodynamic feasibility of the flux. Finally, analysis of the metabolic capabilities of P. falciparum led to the identification of both the minimal nutritional requirements and the genes that can become indispensable upon substrate inaccessibility. This model provides novel insight into the metabolic needs and capabilities of the malaria parasite and highlights metabolites and pathways that should be measured and characterized to identify potential thermodynamic bottlenecks and substrate channeling. The hypotheses presented seek to guide experimental studies to facilitate a better understanding of the parasite metabolism and the identification of targets for more efficient intervention. PMID:28333921

  3. Developing a thermodynamic a conceptual model for the Itumbiara hydroelectric reservoir based on satellite and telemetric data

    Directory of Open Access Journals (Sweden)

    Enner Herenio de Alcântara

    2011-08-01

    Full Text Available Aquatic systems continually respond to climatic conditions that vary over broad scales of space and time. The response of each water body to external conditions (hydro-meteorological processes is revealed in the first place by the thermal structures present in water body. Most lacustrine chemical, physical and biological processes are affected directly by lake hydrological (e.g. lake depth and thermal changes (e.g. seasonal stratification, and are thus, indirectly affected by climate variation. Understanding lake-climate system interactions is therefore of fundamental importance to evaluate the effects of climate change on limnological processes. Based on this, the objective of this work was to develop a thermodynamic conceptual model for the Itumbiara hydroelectric reservoir (Goiás State, Brazil. The developed methodology was based on the use of satellite imagery of moderate resolution that allow the computation of the water surface temperature from 2003 to 2008 (six years during the daytime and nighttime. The results showed the potential of the use of moderate resolution satellite data to study water surface temperature variability and to explain the main causes of this variability. The use of hydro-meteorological and bulk temperature collected by station and autonomous buoy, respectively, contributed to better understand the physical processes in the mixed depth of the reservoir. Also the results allow the elaboration of conceptual models for the thermodynamics of the Itumbiara reservoir.

  4. Application of the ruthenium and technetium thermodynamic data bases used in the EQ3/6 geochemical codes

    International Nuclear Information System (INIS)

    Isherwood, D.

    1985-04-01

    Based on a critical review of the available thermodynamic data, computerized data bases for technetium and ruthenium were created for use with the EQ3/6 geochemical computer codes. The technetium data base contains thermodynamic data for 8 aqueous species and 15 solids; 26 aqueous species and 9 solids were included in the ruthenium data base. The EQ3NR code was used to calculate solubility limits for ruthenium (8 x 10 -16 M) in ground water from Yucca Mountain, a potential nuclear waste repository site near the Nevada Test Site (NTS). The code confirmed the essentially unlimited solubility of technetium in oxidizing conditions, such as those that are believed to exist in the unsaturated zone at Yucca Mountain and the Cambric Nuclear event site at the NTS. Ruthenium migration observed from the Cambric site was evaluated. The solubility limit for ruthenium (as the aqueous species RuO 4 - ) when constrained by RuO 2 is approximately equal to the concentration of ruthenium found in the cavity ground water (i.e., 2.1 x 10 -11 vs 4.5 x 10 -11 M). Differences in ruthenium solubility limits between Yucca Mountain and Cambric are primarily due to differences in ground-water pH. Technetium solubility (3 x 10 -8 M) for moderately reducing conditions (Eh = -0.1 V) using the metastable oxide, TcO 2 .2H 2 O, as the solubility constraint is within the range of experimental values recently published in a study of technetium sorption on basalt. Previously published technetium solubilities of 10 -12 to 10 -16 M were apparently based on a technetium data base that did not include aqueous species other than TcO 4 - . When TcO(OH) 2 0 is included in the data base, the calculated values are much closer to the experimental results. Eh-pH diagrams were also generated for a variety of conditions using the SOLUPLOT code

  5. Characterization of Friction Stir Welded Tubes by Means of Tube Bulge Test

    International Nuclear Information System (INIS)

    D'Urso, G.; Longo, M.; Giardini, C.

    2011-01-01

    Mechanical properties of friction stir welded joints are generally evaluated by means of conventional tensile test. This testing method might provide insufficient information because maximum strain obtained in tensile test before necking is small; moreover, the application of tensile test is limited when the joint path is not linear or even when the welds are executed on curved surfaces. Therefore, in some cases, it would be preferable to obtain the joints properties from other testing methods. Tube bulge test can be a valid solution for testing circumferential or longitudinal welds executed on tubular workpieces. The present work investigates the mechanical properties and the formability of friction stir welded tubes by means of tube bulge tests. The experimental campaign was performed on tubular specimens having a thickness of 3 mm and an external diameter of 40 mm, obtained starting from two semi-tubes longitudinally friction stir welded. The first step, regarding the fabrication of tubes, was performed combining a conventional forming process and friction stir welding. Sheets in Al-Mg-Si-Cu alloy AA6060 T6 were adopted for this purpose. Plates having a dimension of 225x60 mm were bent (with a bending axis parallel to the main dimension) in order to obtain semi-tubes. A particular care was devoted to the fabrication of forming devices (punch and die) in order to minimize the springback effects. Semi-tubes were then friction stir welded by means of a CNC machine tool. Some preliminary tests were carried out by varying the welding parameters, namely feed rate and rotational speed. A very simple tool having flat shoulder and cylindrical pin was used. The second step of the research was based on testing the welded tubes by means of tube bulge test. A specific equipment having axial actuators with a conical shape was adopted for this study. Some analyses were carried out on the tubes bulged up to a certain pressure level. In particular, the burst pressure and the

  6. Statistical thermodynamics

    CERN Document Server

    Schrödinger, Erwin

    1952-01-01

    Nobel Laureate's brilliant attempt to develop a simple, unified standard method of dealing with all cases of statistical thermodynamics - classical, quantum, Bose-Einstein, Fermi-Dirac, and more.The work also includes discussions of Nernst theorem, Planck's oscillator, fluctuations, the n-particle problem, problem of radiation, much more.

  7. Optimization of air plasma reconversion of UF6 to UO2 based on thermodynamic calculations

    Science.gov (United States)

    Tundeshev, Nikolay; Karengin, Alexander; Shamanin, Igor

    2018-03-01

    The possibility of plasma-chemical conversion of depleted uranium-235 hexafluoride (DUHF) in air plasma in the form of gas-air mixtures with hydrogen is considered in the paper. Calculation of burning parameters of gas-air mixtures is carried out and the compositions of mixtures obtained via energy-efficient conversion of DUHF in air plasma are determined. With the help of plasma-chemical conversion, thermodynamic modeling optimal composition of UF6-H2-Air mixtures and its burning parameters, the modes for production of uranium dioxide in the condensed phase are determined. The results of the conducted researches can be used for creation of technology for plasma-chemical conversion of DUHF in the form of air-gas mixtures with hydrogen.

  8. Thermodynamics of adaptive molecular resolution.

    Science.gov (United States)

    Delgado-Buscalioni, R

    2016-11-13

    A relatively general thermodynamic formalism for adaptive molecular resolution (AMR) is presented. The description is based on the approximation of local thermodynamic equilibrium and considers the alchemic parameter λ as the conjugate variable of the potential energy difference between the atomistic and coarse-grained model Φ=U (1) -U (0) The thermodynamic formalism recovers the relations obtained from statistical mechanics of H-AdResS (Español et al, J. Chem. Phys. 142, 064115, 2015 (doi:10.1063/1.4907006)) and provides relations between the free energy compensation and thermodynamic potentials. Inspired by this thermodynamic analogy, several generalizations of AMR are proposed, such as the exploration of new Maxwell relations and how to treat λ and Φ as 'real' thermodynamic variablesThis article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'. © 2016 The Author(s).

  9. Nonequilibrium thermodynamics of nucleation

    NARCIS (Netherlands)

    Schweizer, M.; Sagis, L.M.C.

    2014-01-01

    We present a novel approach to nucleation processes based on the GENERIC framework (general equation for the nonequilibrium reversible-irreversible coupling). Solely based on the GENERIC structure of time-evolution equations and thermodynamic consistency arguments of exchange processes between a

  10. Thermodynamic analysis of a combined-cycle solar thermal power plant with manganese oxide-based thermochemical energy storage

    Science.gov (United States)

    Lei, Qi; Bader, Roman; Kreider, Peter; Lovegrove, Keith; Lipiński, Wojciech

    2017-11-01

    We explore the thermodynamic efficiency of a solar-driven combined cycle power system with manganese oxide-based thermochemical energy storage system. Manganese oxide particles are reduced during the day in an oxygen-lean atmosphere obtained with a fluidized-bed reactor at temperatures in the range of 750-1600°C using concentrated solar energy. Reduced hot particles are stored and re-oxidized during night-time to achieve continuous power plant operation. The steady-state mass and energy conservation equations are solved for all system components to calculate the thermodynamic properties and mass flow rates at all state points in the system, taking into account component irreversibilities. The net power block and overall solar-to-electric energy conversion efficiencies, and the required storage volumes for solids and gases in the storage system are predicted. Preliminary results for a system with 100 MW nominal solar power input at a solar concentration ratio of 3000, designed for constant round-the-clock operation with 8 hours of on-sun and 16 hours of off-sun operation and with manganese oxide particles cycled between 750 and 1600°C yield a net power block efficiency of 60.0% and an overall energy conversion efficiency of 41.3%. Required storage tank sizes for the solids are estimated to be approx. 5-6 times smaller than those of state-of-the-art molten salt systems.

  11. Thermodynamic analysis of a combined-cycle solar thermal power plant with manganese oxide-based thermochemical energy storage

    Directory of Open Access Journals (Sweden)

    Lei Qi

    2017-01-01

    Full Text Available We explore the thermodynamic efficiency of a solar-driven combined cycle power system with manganese oxide-based thermochemical energy storage system. Manganese oxide particles are reduced during the day in an oxygen-lean atmosphere obtained with a fluidized-bed reactor at temperatures in the range of 750–1600°C using concentrated solar energy. Reduced hot particles are stored and re-oxidized during night-time to achieve continuous power plant operation. The steady-state mass and energy conservation equations are solved for all system components to calculate the thermodynamic properties and mass flow rates at all state points in the system, taking into account component irreversibilities. The net power block and overall solar-to-electric energy conversion efficiencies, and the required storage volumes for solids and gases in the storage system are predicted. Preliminary results for a system with 100 MW nominal solar power input at a solar concentration ratio of 3000, designed for constant round-the-clock operation with 8 hours of on-sun and 16 hours of off-sun operation and with manganese oxide particles cycled between 750 and 1600°C yield a net power block efficiency of 60.0% and an overall energy conversion efficiency of 41.3%. Required storage tank sizes for the solids are estimated to be approx. 5–6 times smaller than those of state-of-the-art molten salt systems.

  12. Integrated design of Nb-based superalloys: Ab initio calculations, computational thermodynamics and kinetics, and experimental results

    International Nuclear Information System (INIS)

    Ghosh, G.; Olson, G.B.

    2007-01-01

    An optimal integration of modern computational tools and efficient experimentation is presented for the accelerated design of Nb-based superalloys. Integrated within a systems engineering framework, we have used ab initio methods along with alloy theory tools to predict phase stability of solid solutions and intermetallics to accelerate assessment of thermodynamic and kinetic databases enabling comprehensive predictive design of multicomponent multiphase microstructures as dynamic systems. Such an approach is also applicable for the accelerated design and development of other high performance materials. Based on established principles underlying Ni-based superalloys, the central microstructural concept is a precipitation strengthened system in which coherent cubic aluminide phase(s) provide both creep strengthening and a source of Al for Al 2 O 3 passivation enabled by a Nb-based alloy matrix with required ductile-to-brittle transition temperature, atomic transport kinetics and oxygen solubility behaviors. Ultrasoft and PAW pseudopotentials, as implemented in VASP, are used to calculate total energy, density of states and bonding charge densities of aluminides with B2 and L2 1 structures relevant to this research. Characterization of prototype alloys by transmission and analytical electron microscopy demonstrates the precipitation of B2 or L2 1 aluminide in a (Nb) matrix. Employing Thermo-Calc and DICTRA software systems, thermodynamic and kinetic databases are developed for substitutional alloying elements and interstitial oxygen to enhance the diffusivity ratio of Al to O for promotion of Al 2 O 3 passivation. However, the oxidation study of a Nb-Hf-Al alloy, with enhanced solubility of Al in (Nb) than in binary Nb-Al alloys, at 1300 deg. C shows the presence of a mixed oxide layer of NbAlO 4 and HfO 2 exhibiting parabolic growth

  13. CHARACTERIZATION OF A SAMPLE OF INTERMEDIATE-TYPE ACTIVE GALACTIC NUCLEI. II. HOST BULGE PROPERTIES AND BLACK HOLE MASS ESTIMATES

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Erika; Cruz-Gonzalez, Irene; Martinez, Benoni; Jimenez-Bailon, Elena [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-264, Mexico D.F. 04510 (Mexico); Mendez-Abreu, Jairo; Lopez-Martin, Luis [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Fuentes-Carrera, Isaura [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional (ESFM-IPN), U.P. Adolfo Lopez Mateos, Mexico D.F. 07730 (Mexico); Chavushyan, Vahram [Instituto Nacional de Astrofisica, Optica y Electronica, Apdo. Postal 51-216, 72000 Puebla (Mexico); Leon-Tavares, Jonathan, E-mail: erika@astro.unam.mx [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, 02540 Kylmaelae (Finland)

    2013-02-15

    We present a study of the host bulge properties and their relations with the black hole mass for a sample of 10 intermediate-type active galactic nuclei (AGNs). Our sample consists mainly of early-type spirals, four of them hosting a bar. For 70{sup +10} {sub -17}% of the galaxies, we have been able to determine the type of the bulge, and find that these objects probably harbor a pseudobulge or a combination of classical bulge/pseudobulge, suggesting that pseudobulges might be frequent in intermediate-type AGNs. In our sample, 50% {+-} 14% of the objects show double-peaked emission lines. Therefore, narrow double-peaked emission lines seem to be frequent in galaxies harboring a pseudobulge or a combination of classical bulge/pseudobulge. Depending on the bulge type, we estimated the black hole mass using the corresponding M {sub BH}-{sigma}* relation and found them within a range of 5.69 {+-} 0.21 < log M {sup {sigma}}*{sub BH} < 8.09 {+-} 0.24. Comparing these M {sup {sigma}}*{sub BH} values with masses derived from the FWHM of H{beta} and the continuum luminosity at 5100 A from their SDSS-DR7 spectra (M {sub BH}), we find that 8 out of 10 (80{sup +7} {sub -17}%) galaxies have black hole masses that are compatible within a factor of 3. This result would support that M {sub BH} and M {sup {sigma}}*{sub BH} are the same for intermediate-type AGNs, as has been found for type 1 AGNs. However, when the type of the bulge is taken into account, only three out of the seven (43{sup +18} {sub -15}%) objects of the sample have their M {sup {sigma}}*{sub BH} and M {sub BH} compatible within 3{sigma} errors. We also find that estimations based on the M {sub BH}-{sigma}* relation for pseudobulges are not compatible in 50% {+-} 20% of the objects.

  14. The thermodynamics of protein folding: a critique of widely used quasi-thermodynamic interpretations and a restatement based on the Gibbs-Duhem relation and consistent with the Phase Rule.

    Science.gov (United States)

    Pethica, Brian A

    2010-07-21

    Interpretations of data in the extensive literature on the unfolding of proteins in aqueous solution follow a variety of methods involving assumptions leading to estimates of thermodynamic quantities associated with the unfolding transition. Inconsistencies and thermodynamic errors in these methods are identified. Estimates of standard molar free energies and enthalpies of unfolding using incompletely defined equilibrium constants and the van't Hoff relation are unsound, and typically contradict model-free interpretation of the data. A widely used routine for estimating the change in heat capacity associated with unfolding based on changes in the unfolding temperature and enthalpy co-induced by addition of denaturant or protective additives is thermodynamically incorrect by neglect of the Phase Rule. Many models and simulations predicting thermodynamic measures of unfolding are presently making comparisons with insecure quantities derived by incorrect thermodynamic analyses of experimental data. Analysis of unfolding via the Gibbs-Duhem equation with the correct Phase Rule constraints avoids the assumptions associated with incomplete equilibrium constants and misuse of the van't Hoff relation, and applies equally to positive, negative, sitewise or diffuse solute binding to the protein. The method gives the necessary relations between the thermodynamic parameters for thermal and isothermal unfolding and is developed for the case of two-state unfolding. The differences in binding of denaturants or stabilizers to the folded and unfolded forms of the protein are identified as major determinants of the unfolding process. The Phase Rule requires the temperature and enthalpy of unfolding to depend generally on the protein concentration. The available evidence bears out this expectation for thermal unfolding, indicating that protein-protein interactions influence folding. A parallel dependence of the denaturant concentrations for isothermal unfolding on the protein

  15. Hydrogen production from natural gas using an iron-based chemical looping technology: Thermodynamic simulations and process system analysis

    International Nuclear Information System (INIS)

    Kathe, Mandar V.; Empfield, Abbey; Na, Jing; Blair, Elena; Fan, Liang-Shih

    2016-01-01

    Highlights: • Design of iron-based chemical looping process using moving bed for H 2 from CH 4 . • Auto-thermal operation design using thermodynamic rationale for 90% carbon capture. • Cold gas efficiency: 5% points higher than Steam Methane Reforming baseline case. • Net thermal efficiency: 6% points higher than Steam Methane Reforming baseline case. • Sensitivity analysis: Energy recovery scheme, operating pressure, no carbon capture. - Abstract: Hydrogen (H 2 ) is a secondary fuel derived from natural gas. Currently, H 2 serves as an important component in refining operations, fertilizer production, and is experiencing increased utilization in the transportation industry as a clean combustion fuel. In recent years, industry and academia have focused on developing technology that reduces carbon emissions. As a result, there has been an increase in the technological developments for producing H 2 from natural gas. These technologies aim to minimize the cost increment associated with clean energy production. The natural gas processing chemical looping technology, developed at The Ohio State University (OSU), employs an iron-based oxygen carrier and a novel gas–solid counter-current moving bed reactor for H 2 production. Specifically, this study examines the theoretical thermodynamic limits for full conversion of natural gas through iron-based oxygen carrier reactions with methane (CH 4 ), by utilizing simulations generated with ASPEN modeling software. This study initially investigates the reducer and the oxidizer thermodynamic phase diagrams then derives an optimal auto-thermal operating condition for the complete loop simulation. This complete loop simulation is initially normalized for analysis on the basis of one mole of carbon input from natural gas. The H 2 production rate is then scaled to match that of the baseline study, using a full-scale ASPEN simulation for computing cooling loads, water requirements and net parasitic energy consumption. The

  16. On the kinematic separation of field and cluster stars across the bulge globular NGC 6528

    Energy Technology Data Exchange (ETDEWEB)

    Lagioia, E. P.; Bono, G.; Buonanno, R. [Dipartimento di Fisica, Università degli Studi di Roma-Tor Vergata, via della Ricerca Scientifica 1, I-00133 Roma (Italy); Milone, A. P. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston, ACT 2611 (Australia); Stetson, P. B. [Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Prada Moroni, P. G. [Dipartimento di Fisica, Università di Pisa, I-56127 Pisa (Italy); Dall' Ora, M. [INAF-Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); Aparicio, A.; Monelli, M. [Instituto de Astrofìsica de Canarias, E-38200 La Laguna, Tenerife, Canary Islands (Spain); Calamida, A.; Ferraro, I.; Iannicola, G. [INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-00044 Monte Porzio Catone (Italy); Gilmozzi, R. [European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching (Germany); Matsunaga, N. [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, 10762-30, Mitake, Kiso-machi, Kiso-gun, 3 Nagano 97-0101 (Japan); Walker, A., E-mail: eplagioia@roma2.infn.it [Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)

    2014-02-10

    We present deep and precise multi-band photometry of the Galactic bulge globular cluster NGC 6528. The current data set includes optical and near-infrared images collected with ACS/WFC, WFC3/UVIS, and WFC3/IR on board the Hubble Space Telescope. The images cover a time interval of almost 10 yr, and we have been able to carry out a proper-motion separation between cluster and field stars. We performed a detailed comparison in the m {sub F814W}, m {sub F606W} – m {sub F814W} color-magnitude diagram with two empirical calibrators observed in the same bands. We found that NGC 6528 is coeval with and more metal-rich than 47 Tuc. Moreover, it appears older and more metal-poor than the super-metal-rich open cluster NGC 6791. The current evidence is supported by several diagnostics (red horizontal branch, red giant branch bump, shape of the sub-giant branch, slope of the main sequence) that are minimally affected by uncertainties in reddening and distance. We fit the optical observations with theoretical isochrones based on a scaled-solar chemical mixture and found an age of 11 ± 1 Gyr and an iron abundance slightly above solar ([Fe/H] = +0.20). The iron abundance and the old cluster age further support the recent spectroscopic findings suggesting a rapid chemical enrichment of the Galactic bulge.

  17. A "bulged" double helix in a RNA-protein contact site

    DEFF Research Database (Denmark)

    Peattie, D A; Douthwaite, S; Garrett, R A

    1981-01-01

    The binding of ribosomal protein L18 affects specific nucleotides in Escherichia coli 5S RNA as detected by dimethyl sulfate alkylation and RNase A digestion of the 5S-L18 complex. Most of the affected nucleotides are clustered and localize a site of RNA-protein interaction in and around...... the defined central helix [Fox, G. E. & Woese, C. (1975) Nature (London) 256, 505-507] of 5S RNA. Chemical carbethoxylation of the native 5S RNA with diethyl pyrocarbonate shows that a striking feature of this region is an unstacked adenosine residue at position 66. We propose that this residue exists...... as a singly bulged nucleotide extending the Fox and Woese central helix by two base pairs in the E. coli sequence (to positions 16-23/60-68) as well as in each of 61 (prokaryotic and eukaryotic) aligned 5S RNA sequences. In each case, the single bulged nucleotide is at the relative position of adenosine-66...

  18. Set of molecular models based on quantum mechanical ab initio calculations and thermodynamic data.

    Science.gov (United States)

    Eckl, Bernhard; Vrabec, Jadran; Hasse, Hans

    2008-10-09

    A parametrization strategy for molecular models on the basis of force fields is proposed, which allows a rapid development of models for small molecules by using results from quantum mechanical (QM) ab initio calculations and thermodynamic data. The geometry of the molecular models is specified according to the atom positions determined by QM energy minimization. The electrostatic interactions are modeled by reducing the electron density distribution to point dipoles and point quadrupoles located in the center of mass of the molecules. Dispersive and repulsive interactions are described by Lennard-Jones sites, for which the parameters are iteratively optimized to experimental vapor-liquid equilibrium (VLE) data, i.e., vapor pressure, saturated liquid density, and enthalpy of vaporization of the considered substance. The proposed modeling strategy was applied to a sample set of ten molecules from different substance classes. New molecular models are presented for iso-butane, cyclohexane, formaldehyde, dimethyl ether, sulfur dioxide, dimethyl sulfide, thiophene, hydrogen cyanide, acetonitrile, and nitromethane. Most of the models are able to describe the experimental VLE data with deviations of a few percent.

  19. DFT-based prediction of geometric and thermodynamic parameters in the ATP to ADP hydrolysis reaction

    Science.gov (United States)

    Palenik, Mark C.; Rodriguez, Jorge H.

    2013-03-01

    Studying covalent (chemical) and noncovalent (physical) mechanisms as well as key structural variations associated with ATP --> ADP hydrolysis is of interest for understanding a multitude of biophysical and biochemical cellular processes. We have studied geometric variations of the ATP and ADP molecules during their hydrolysis reaction using density functional theory (DFT) with an implicit solvation model. We have computed the change in free energy, ΔG, associated with the hydrolysis reaction and established relationships between key geometric parameters and thermodynamic properties. Our computed values for ΔG were found in good agreement with available experimental data for two different sets of geometric conformations. A link is suggested between these values for ΔG and changes in geometry of the ADP molecule. Of methodological and computational interest, we also determined that, while the conductor-like solvation model in the framework of the polarizable continuum model (C-PCM) was capable of producing biochemically meaningful geometries for ATP and ADP, it also displayed a strong preference for binding between the H+ and PO42 - ions formed during hydrolysis.

  20. Thermodynamic analysis of hydrocarbon refrigerants-based ethylene BOG re-liquefaction system

    Science.gov (United States)

    Beladjine, Boumedienne M.; Ouadha, Ahmed; Addad, Yacine

    2016-09-01

    The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane (R290), butane (R600), isobutane (R600a), and propylene (R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system's performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600a gives the best performance, followed by (in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.

  1. Thermodynamic constrains for life based on non-aqueous polar solvents on free-floating planets.

    Science.gov (United States)

    Badescu, Viorel

    2011-02-01

    Free-floating planets (FFPs) might originate either around a star or in solitary fashion. These bodies can retain molecular gases atmospheres which, upon cooling, have basal pressures of tens of bars or more. Pressure-induced opacity of these gases prevents such a body from eliminating its internal radioactive heat and its surface temperature can exceed for a long term the melting temperature of a life-supporting solvent. In this paper two non-aqueous but still polar solvents are considered: hydrogen sulfide and ammonia. Thermodynamic requirements to be fulfilled by a hypothetic gas constituent of a life-supporting FFP's atmosphere are studied. The three gases analyzed here (nitrogen, methane and ethane) are candidates. We show that bodies with ammonia oceans are possible in interstellar space. This may happen on FFPs of (significantly) smaller or larger mass than the Earth. Generally, in case of FFP smaller in size than the Earth, the atmosphere exhibits a convective layer near the surface and a radiative layer at higher altitudes while the atmosphere of FFPs larger in size than Earth does not exhibit a convective layer. The atmosphere mass of a life-hosting FFP of Earth size is two or three orders of magnitude larger than the mass of Earth atmosphere. For FFPs larger than the Earth and specific values of surface pressure and temperature, there are conditions for condensation (in the ethane atmosphere). Some arguments induce the conclusion than the associated surface pressures and temperatures should be treated with caution as appropriate life conditions.

  2. Determination of thermodynamic properties of aluminum based binary and ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Altıntas, Yemliha [Abdullah Gül University, Faculty of Engineering, Department of Materials Science and Nanotechnology, 38039, Kayseri (Turkey); Aksöz, Sezen [Nevşehir Hacı Bektaş Veli University, Faculty of Arts and Science, Department of Physics, 50300, Nevşehir (Turkey); Keşlioğlu, Kâzım, E-mail: kesli@erciyes.edu.tr [Erciyes University, Faculty of Science, Department of Physics, 38039, Kayseri (Turkey); Maraşlı, Necmettin [Yıldız Technical University, Faculty of Chemical and Metallurgical Engineering, Department of Metallurgical and Materials Engineering, 34210, Davutpaşa, İstanbul (Turkey)

    2015-11-15

    In the present work, the Gibbs–Thomson coefficient, solid–liquid and solid–solid interfacial energies and grain boundary energy of a solid Al solution in the Al–Cu–Si eutectic system were determined from the observed grain boundary groove shapes by measuring the thermal conductivity of the solid and liquid phases and temperature gradient. Some thermodynamic properties such as the enthalpy of fusion, entropy of fusion, the change of specific heat from liquid to solid and the electrical conductivity of solid phases at their melting temperature were also evaluated by using the measured values of relevant data for Al–Cu, Al–Si, Al–Mg, Al–Ni, Al–Ti, Al–Cu–Ag, Al–Cu–Si binary and ternary alloys. - Highlights: • The microstructure of the Al–Cu–Si eutectic alloy was observed through SEM. • The three eutectic phases (α-Al, Si, CuAl{sub 2}) have been determined by EDX analysis. • Solid–liquid and solid–solid interfacial energies of α-Al solution were determined. • ΔS{sub f},ΔH{sub M}, ΔC{sub P}, electrical conductivity of solid phases for solid Al solutions were determined. • G–T coefficient and grain boundary energy of solid Al solution were determined.

  3. Effects of sulfur on lead partitioning during sludge incineration based on experiments and thermodynamic calculations.

    Science.gov (United States)

    Liu, Jing-yong; Huang, Shu-jie; Sun, Shui-yu; Ning, Xun-an; He, Rui-zhe; Li, Xiao-ming; Chen, Tao; Luo, Guang-qian; Xie, Wu-ming; Wang, Yu-Jie; Zhuo, Zhong-xu; Fu, Jie-wen

    2015-04-01

    Experiments in a tubular furnace reactor and thermodynamic equilibrium calculations were conducted to investigate the impact of sulfur compounds on the migration of lead (Pb) during sludge incineration. Representative samples of typical sludge with and without the addition of sulfur compounds were combusted at 850 °C, and the partitioning of Pb in the solid phase (bottom ash) and gas phase (fly ash and flue gas) was quantified. The results indicate that three types of sulfur compounds (S, Na2S and Na2SO4) added to the sludge could facilitate the volatilization of Pb in the gas phase (fly ash and flue gas) into metal sulfates displacing its sulfides and some of its oxides. The effect of promoting Pb volatilization by adding Na2SO4 and Na2S was superior to that of the addition of S. In bottom ash, different metallic sulfides were found in the forms of lead sulfide, aluminosilicate minerals, and polymetallic-sulfides, which were minimally volatilized. The chemical equilibrium calculations indicated that sulfur stabilizes Pb in the form of PbSO4(s) at low temperatures (sludge incineration process mainly depended on the gas phase reaction, the surface reaction, the volatilization of products, and the concentration of Si, Ca and Al-containing compounds in the sludge. These findings provide useful information for understanding the partitioning behavior of Pb, facilitating the development of strategies to control the volatilization of Pb during sludge incineration. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. A Comparison of Galaxy Bulge+Disk Decomposition Between Pan-STARRS and SDSS

    Science.gov (United States)

    Lokken, Martine Elena; McPartland, Conor; Sanders, David B.

    2018-01-01

    Measurements of the size and shape of bulges in galaxies provide key constraints for models of galaxy evolution. A comprehensive catalog of bulge measurements for Sloan Digital Sky Survey (SDSS) DR7 galaxies is currently available to the public. However, the Pan-STARRS1 (PS1) 3π survey now covers the same region with ~1-2 mag deeper photometry, a ~10-30% smaller PSF, and additional coverage in y-band. To test how much improvement in galaxy parameter measurements (e.g. bulge + disk) can be achieved using the new PS1 data, we make use of ultra-deep imaging data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program (SSP). We fit bulge+disk models to images of 372 bright (mi < 18.5) galaxies detected in all three surveys. Comparison of galaxy parameters derived from SDSS and PS1 images with those measured from HSC-SSP images shows a tighter correlation between PS1 and SSP measurements for both bulge and disk parameters. Bulge parameters, such as bulge-to-total fraction and bulge radius, show the strongest improvement. However, measurements of all parameters degrade for galaxies with total r-band magnitude below the SDSS spectroscopic limit, mr = 17.7. We plan to use the PS1 3π survey data to produce an updated catalog of bulge+disk decomposition measurements for the entire SDSS DR7 spectroscopic galaxy sample.

  5. Bar formation in disk galaxies, and the normalized angular momentum of the bulge

    Energy Technology Data Exchange (ETDEWEB)

    Zasov, A.V.

    1985-09-01

    In 1971 Polyachenko et al. suggested that the spheroidal bulge in a spiral galaxy would retain a biaxial shape unless its normalized angular momentum, defined as M = KM/sub b//sup -5/3/ (K is the ordinary angular momentum and M/sub b/ the mass of the bulge), exceeds some critical value; in that event a triaxial ellipsoid: a bar: would develop. This proposal is in fact consistent with bulge rotational velocities observed in disk-type systems. The bar presumably represents a bulge component having a high M value.

  6. Lattice and electronic properties of strongly correlated PuCoGa5 based on first principles calculations and thermodynamic modelling

    Science.gov (United States)

    Filanovich, A. N.; Povzner, A. A.

    2017-12-01

    In the framework of density functional theory method, the ground state energy of the PuCoGa5 compound is calculated for different values of the unit cell volume. The obtained data were incorporated into the thermodynamic model, which was utilized to calculate the temperature dependencies of thermal and elastic properties of PuCoGa5. The parameters of the developed model were estimated based on data of ab initio phonon spectrum. The Gruneisen parameters, which characterize degree of anharmonicity of the acoustic and optical phonons, are obtained. Using experimental data, non-lattice contributions to the coefficient of thermal expansion and heat capacity are determined. The nature of observed anomalies of the properties of PuCoGa5 is discussed, in particular, the possibility of a valence phase transition.

  7. Thermodynamic Model of a Very High Efficiency Power Plant based on a Biomass Gasifier, SOFCs, and a Gas Turbine

    Directory of Open Access Journals (Sweden)

    P V Aravind

    2012-07-01

    Full Text Available Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable.

  8. FORMATION CONSTANTS AND THERMODYNAMIC ...

    African Journals Online (AJOL)

    , Ni(II), Cu(II) and Zn(II) ions has been ... A good deal of work has been reported on the preparation and structural investigation of. Schiff base ... Formation constants and thermodynamic parameters of Co, Ni, Cu and Zn complexes. Bull. Chem.

  9. A new closed-form analytical thermal model for simulating Stirling engines based on polytropic-finite speed thermodynamics

    International Nuclear Information System (INIS)

    Hosseinzade, Hadi; Sayyaadi, Hoseyn; Babaelahi, Mojtaba

    2015-01-01

    Highlights: • A closed-form thermal model was presented for Stirling engines. • The new model was used to simulate the GPU-3 Stirling engine. • Results were compared with experimental data as well as other models. • The new model was more accurate and simple in calculation than other models. • Effects of the engines’ parameters on operation of engine were evaluated. - Abstract: Thermal models for the simulation of Stirling engines need to have greater accuracy along with simple and low-cost calculation. In this regard, a new closed-form thermal model was presented for the thermal simulation of Stirling engines. The new model called PFST (polytropic-finite speed thermodynamics) was developed based on the combination of polytropic analysis of expansion/compression processes and the concept of finite speed thermodynamics (FST). Therefore, compression/expansion works of compression/expansion processes and transferred heat into the heater of Stirling engines were determined based on polytropic analysis, instead of isothermal processes of the ideal Stirling cycle. The calculated work of polytropic processes was corrected to include the effects of internal irreversibilities including pressure throttling in heat exchangers, mechanical friction, and finite motion of the pistons. Output power and thermal efficiency of Stirling engines were calculated as functions of various engine parameters. The developed PFST model was implemented on a prototype Stirling engine, called GPU-3 engine, and the obtained results were compared with those of other closed-form and numerical models as well as experimental data. It was found that the new closed-form model, in addition to its simple and low-cost calculation, had the same order of accuracy as recently developed numerical models

  10. Thermodynamics. An introduction into its bases and technical applications. 14. ed.; Thermodynamik. Grundlagen und technische Anwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Baehr, Hans Dieter [Hannover Univ. (Germany). Inst. fuer Thermodynamik; Kabelac, Stephan [Helmut-Schmidt-Univ., Univ. der Bundeswehr Hamburg (Germany). Inst. fuer Thermodynamik

    2009-07-01

    The actualized 14th edition covers now a further chapter on energy conversion: the structure of energy demand in Germany is discussed and patterns of energy conversion highlighted. Furtheron practical application on combustion processes, thermal power plants, carbon dioxide and power generation, heating systems and refrigerating machinery are completed. The concepts of exergy and energy are introduced by postulates instead of being constructed on the basis of certain theorems; this is to give the students easier access to the fundamental balance equations which are the basic elements in the quantitative statements of the two basic laws of thermodynamics and are indispensable for their application. The balance equations are expressed in as general a form as possible taking account also of transient processes of open systems and of the special case of steady flow processes. (orig./GL) [German] die aktualisierte 14. Auflage des bewaehrten Lehrbuchs der Technischen Thermodynamik wurde das Kapitel ueber Waermekraftanlagen gruendlich bearbeitet und durch einen Abschnitt zur Energiewandlung ergaenzt: Die Energiebedarfsstruktur von Deutschland wird erlaeutert, und die moeglichen Energiewandlungspfade werden diskutiert. Schwerpunkt des Buches ist die ausfuehrliche und auch dem Anfaenger verstaendliche Darstellung der Grundlagen der Thermodynamik mit der sorgfaeltigen Einfuehrung der thermodynamischen Begriffe und den fundamentalen Bilanzgleichungen fuer Energie, Entropie und Exergie. Die thermodynamischen Eigenschaften reiner Fluide und fluider Gemische werden eingehend erlaeutert. Darauf aufbauend wird die Thermodynamik der Gemische und der chemischen Reaktionen entwickelt. Auch die thermodynamischen Aspekte wichtiger energie- und verfahrenstechnischer Anwendungen werden praxisnah behandelt: - Stroemungs- und Arbeitsprozesse, - thermische Stofftrennverfahren, - Verbrennungsprozesse und Verbrennungskraftanlagen, - thermische Kraftwerke, - CO2-Emissionen der Stromerzeugung

  11. Thermodynamic Based Framework for Determining Sustainable Electric Infrastructures as well as Modeling of Decoherence in Quantum Composite Systems

    Science.gov (United States)

    Cano-Andrade, Sergio

    In this dissertation, applications of thermodynamics at the macroscopic and quantum levels of description are developed. Within the macroscopic level, an upper-level Sustainability Assessment Framework (SAF) is proposed for evaluating the sustainable and resilient synthesis/design and operation of sets of small renewable and non-renewable energy production technologies coupled to power production transmission and distribution networks via microgrids. The upper-level SAF is developed in accord with the four pillars of sustainability, i.e., economic, environmental, technical and social. A superstructure of energy producers with a fixed transmission network initially available is synthesized based on the day with the highest energy demand of the year, resulting in an optimum synthesis, design, and off-design network configuration. The optimization is developed in a quasi-stationary manner with an hourly basis, including partial-load behavior for the producers. Since sustainability indices are typically not expressed in the same units, multicriteria decision making methods are employed to obtain a composite sustainability index. Within the quantum level of description, steepest-entropy-ascent quantum thermodynamics (SEA-QT) is used to model the phenomenon of decoherence. The two smallest microscopic composite systems encountered in Nature are studied. The first of these is composed of two two-level-type particles, while the second one is composed of a two-level-type particle and an electromagnetic field. Starting from a non-equilibrium state of the composite and for each of the two different composite systems, the time evolution of the state of the composite as well as that of the reduced and locally-perceived states of the constituents are traced along their relaxation towards stable equilibrium at constant system energy. The modeling shows how the initial entanglement and coherence between constituents are reduced during the relaxation towards a state of stable

  12. Looking for imprints of the first stellar generations in metal-poor bulge field stars

    Science.gov (United States)

    Siqueira-Mello, C.; Chiappini, C.; Barbuy, B.; Freeman, K.; Ness, M.; Depagne, E.; Cantelli, E.; Pignatari, M.; Hirschi, R.; Frischknecht, U.; Meynet, G.; Maeder, A.

    2016-09-01

    Context. Efforts to look for signatures of the first stars have concentrated on metal-poor halo objects. However, the low end of the bulge metallicity distribution has been shown to host some of the oldest objects in the Milky Way and hence this Galactic component potentially offers interesting targets to look at imprints of the first stellar generations. As a pilot project, we selected bulge field stars already identified in the ARGOS survey as having [Fe/H] ≈-1 and oversolar [α/Fe] ratios, and we used FLAMES-UVES to obtain detailed abundances of key elements that are believed to reveal imprints of the first stellar generations. Aims: The main purpose of this study is to analyse selected ARGOS stars using new high-resolution (R ~ 45 000) and high-signal-to-noise (S/N> 100) spectra. We aim to derive their stellar parameters and elemental ratios, in particular the abundances of C, N, the α-elements O, Mg, Si, Ca, and Ti, the odd-Z elements Na and Al, the neutron-capture s-process dominated elements Y, Zr, La, and Ba, and the r-element Eu. Methods: High-resolution spectra of five field giant stars were obtained at the 8 m VLT UT2-Kueyen telescope with the UVES spectrograph in FLAMES-UVES configuration. Spectroscopic parameters were derived based on the excitation and ionization equilibrium of Fe I and Fe II. The abundance analysis was performed with a MARCS LTE spherical model atmosphere grid and the Turbospectrum spectrum synthesis code. Results: We confirm that the analysed stars are moderately metal-poor (-1.04 ≤ [Fe/H] ≤-0.43), non-carbon-enhanced (non-CEMP) with [C/Fe] ≤ + 0.2, and α-enhanced. We find that our three most metal-poor stars are nitrogen enhanced. The α-enhancement suggests that these stars were formed from a gas enriched by core-collapse supernovae, and that the values are in agreement with results in the literature for bulge stars in the same metallicity range. No abundance anomalies (Na - O, Al - O, Al - Mg anti-correlations) were

  13. Extinction maps toward the Milky Way bulge: Two-dimensional and three-dimensional tests with apogee

    Energy Technology Data Exchange (ETDEWEB)

    Schultheis, M. [Université de Nice Sophia-Antipolis, CNRS, Observatoire de Côte d' Azur, Laboratoire Lagrange, 06304 Nice Cedex 4 (France); Zasowski, G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Allende Prieto, C. [Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Anders, F.; Chiappini, C. [Leibniz-Institut für Astrophysik Potsdam (AIP), D-14482 Potsdam (Germany); Beaton, R. L.; García Pérez, A. E.; Majewski, S. R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Beers, T. C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Bizyaev, D. [Apache Point Observatory, Sunspot, NM 88349 (United States); Frinchaboy, P. M. [Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); Ge, J. [Astronomy Department, University of Florida, Gainesville, FL 32611 (United States); Hearty, F.; Schneider, D. P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Holtzman, J. [New Mexico State University, Las Cruces, NM 88003 (United States); Muna, D. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Nidever, D. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Shetrone, M., E-mail: mathias.schultheis@oca.eu, E-mail: gail.zasowski@gmail.com [McDonald Observatory, The University of Texas at Austin, Austin, TX 78712 (United States)

    2014-07-01

    Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both two-dimensional and three-dimensional extinction maps, using independent extinction measures based on a large spectroscopic sample of stars toward the Milky Way bulge. We employ stellar atmospheric parameters derived from high-resolution H-band Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectra, combined with theoretical stellar isochrones, to calculate line-of-sight extinction and distances for a sample of more than 2400 giants toward the Milky Way bulge. We compare these extinction values to those predicted by individual near-IR and near+mid-IR stellar colors, two-dimensional bulge extinction maps, and three-dimensional extinction maps. The long baseline, near+mid-IR stellar colors are, on average, the most accurate predictors of the APOGEE extinction estimates, and the two-dimensional and three-dimensional extinction maps derived from different stellar populations along different sightlines show varying degrees of reliability. We present the results of all of the comparisons and discuss reasons for the observed discrepancies. We also demonstrate how the particular stellar atmospheric models adopted can have a strong impact on this type of analysis, and discuss related caveats.

  14. Extinction maps toward the Milky Way bulge: Two-dimensional and three-dimensional tests with apogee

    International Nuclear Information System (INIS)

    Schultheis, M.; Zasowski, G.; Allende Prieto, C.; Anders, F.; Chiappini, C.; Beaton, R. L.; García Pérez, A. E.; Majewski, S. R.; Beers, T. C.; Bizyaev, D.; Frinchaboy, P. M.; Ge, J.; Hearty, F.; Schneider, D. P.; Holtzman, J.; Muna, D.; Nidever, D.; Shetrone, M.

    2014-01-01

    Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both two-dimensional and three-dimensional extinction maps, using independent extinction measures based on a large spectroscopic sample of stars toward the Milky Way bulge. We employ stellar atmospheric parameters derived from high-resolution H-band Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectra, combined with theoretical stellar isochrones, to calculate line-of-sight extinction and distances for a sample of more than 2400 giants toward the Milky Way bulge. We compare these extinction values to those predicted by individual near-IR and near+mid-IR stellar colors, two-dimensional bulge extinction maps, and three-dimensional extinction maps. The long baseline, near+mid-IR stellar colors are, on average, the most accurate predictors of the APOGEE extinction estimates, and the two-dimensional and three-dimensional extinction maps derived from different stellar populations along different sightlines show varying degrees of reliability. We present the results of all of the comparisons and discuss reasons for the observed discrepancies. We also demonstrate how the particular stellar atmospheric models adopted can have a strong impact on this type of analysis, and discuss related caveats.

  15. Thermodynamic analysis of a Kalina-based combined cooling and power cycle driven by low-grade heat source

    International Nuclear Information System (INIS)

    Cao, Liyan; Wang, Jiangfeng; Wang, Hongyang; Zhao, Pan; Dai, Yiping

    2017-01-01

    Highlights: • A Kalina-based combined cooling and power cycle is proposed to recover low-grade heat source. • The effects of several parameters on cycle performance are examined. • An optimization is conducted by GA to obtain optimum performance. - Abstract: This paper investigates a Kalina-based combined cooling and power (CCP) cycle driven by low-grade heat source. The proposed cycle consists of a Kalina cycle and an absorption refrigeration cycle. By establishing the mathematical model, numerical simulation is conducted and parametric analysis is performed to examine the effects of five key parameters on the thermodynamic performances of Kalina-based CCP cycle. A performance optimization is conducted by genetic algorithm to obtain the optimum exergy efficiency. According to parametric analysis, an optimum expander inlet pressure can be achieved; exergy efficiency increases with expander inlet pressure and concentration of ammonia-water basic solution, but exergy efficiency decreases when terminal temperature difference of high-temperature recuperator and low-temperature recuperator increases. Refrigeration exergy increases with expander inlet pressure and decreases as expander inlet temperature and concentration of ammonia-water basic solution rise. However, the refrigeration exergy keeps constant as the terminal temperature difference of high-temperature recuperator and low-temperature recuperator vary. Furthermore, the optimized Kalina-based CCP cycle is compared with a separate generation system which is also optimized. The optimization results show that the exergy efficiency and net power output of Kalina-based CCP are higher than those of separate generation system.

  16. A study of the effect of bulges on bar formation in disc galaxies

    Science.gov (United States)

    Kataria, Sandeep Kumar; Das, Mousumi

    2018-04-01

    We use N-body simulations of bar formation in isolated galaxies to study the effect of bulge mass and bulge concentration on bar formation. Bars are global disc instabilities that evolve by transferring angular momentum from the inner to outer discs and to the dark matter halo. It is well known that a massive spherical component such as halo in a disc galaxy can make it bar stable. In this study, we explore the effect of another spherical component, the bulge, on bar formation in disc galaxies. In our models, we vary both the bulge mass and concentration. We have used two sets of models: one that has a dense bulge and high surface density disc, and the other model has a less concentrated bulge and a lighter disc. In both models, we vary the bulge to disc mass fraction from 0 to 0.7. Simulations of both the models show that there is an upper cut-off in bulge-to-disc mass ratio Mb/Md above which bars cannot form; the cut-off is smaller for denser bulges (Mb/Md = 0.2) compared to less denser ones (Mb/Md = 0.5). We define a new criterion for bar formation in terms of the ratio of bulge to total radial force (Fb/Ftot) at the disc scale lengths above which bars cannot form. We find that if Fb/Ftot > 0.35, a disc is stable and a bar cannot form. Our results indicate that early-type disc galaxies can still form strong bars in spite of having massive bulges.

  17. THE BLACK HOLE MASS-BULGE LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI FROM REVERBERATION MAPPING AND HUBBLE SPACE TELESCOPE IMAGING

    International Nuclear Information System (INIS)

    Bentz, Misty C.; Peterson, Bradley M.; Pogge, Richard W.; Vestergaard, Marianne

    2009-01-01

    We investigate the relationship between black hole mass and bulge luminosity for active galactic nuclei (AGNs) with reverberation-based black hole mass measurements and bulge luminosities from two-dimensional decompositions of Hubble Space Telescope host galaxy images. We find that the slope of the relationship for AGNs is 0.76-0.85 with an uncertainty of ∼0.1, somewhat shallower than the M BH ∝ L 1.0±0.1 relationship that has been fit to nearby quiescent galaxies with dynamical black hole mass measurements. This difference is somewhat perplexing, as the AGN black hole masses include an overall scaling factor that brings the AGN M BH -σ * relationship into agreement with that of quiescent galaxies. We discuss biases that may be inherent to the AGN and quiescent galaxy samples and could cause the apparent inconsistency in the forms of their M BH -L bulge relationships. Recent work by Graham, however, presents a similar slope of ∼0.8 for the quiescent galaxies and may bring the relationship for AGNs and quiescent galaxies into agreement.

  18. Thermodynamic modeling of ionic liquid systems: development and detailed overview of novel methodology based on the PC-SAFT.

    Science.gov (United States)

    Paduszyński, Kamil; Domańska, Urszula

    2012-04-26

    We present the results of an extensive study on a novel approach of modeling ionic liquids (ILs) and their mixtures with molecular compounds, incorporating perturbed-chain statistical associating fluid theory (PC-SAFT). PC-SAFT was used to calculate the thermodynamic properties of different homologous series of ILs based on the bis(trifluormethylsulfonyl)imide anion ([NTf2]). First, pure fluid parameters were obtained for each IL by means of fitting the model predictions to experimental liquid densities over a broad range of temperature and pressure. The reliability and physical significance of the parameters as well as the employed molecular scheme were tested by calculation of density, vapor pressure, and other properties of pure ILs (e.g., critical properties, normal boiling point). Additionally, the surface tension of pure ILs was calculated by coupling the PC-SAFT equation of state with density gradient theory (DGT). All correlated/predicted results were compared with literature experimental or simulation data. Afterward, we attempted to model various thermodynamic properties of some binary systems composed of IL and organic solvent or water. The properties under study were the binary vapor-liquid, liquid-liquid, and solid-liquid equilibria and the excess enthalpies of mixing. To calculate cross-interaction energies we used the standard combining rules of Lorentz-Berthelot, Kleiner-Sadowski, and Wolbach-Sandler. It was shown that incorporation of temperature-dependent binary corrections was required to obtain much more accurate results than in the case of conventional predictions. Binary corrections were adjusted to infinite dilution activity coefficients of a particular solute in a given IL determined experimentally or predicted by means of the modified UNIFAC (Dortmund) group contribution method. We concluded that the latter method allows accurate and reliable calculations of bulk-phase properties in a totally predictive manner.

  19. Ecosystem thermodynamics

    International Nuclear Information System (INIS)

    Gomez Palacio, German Rau

    1998-01-01

    Ecology is no more a descriptive and self-sufficient science. Many viewpoints are needed simultaneously to give a full coverage of such complex systems: ecosystems. These viewpoints come from physics, chemistry, and nuclear physics, without a new far from equilibrium thermodynamics and without new mathematical tools such as catastrophe theory, fractal theory, cybernetics and network theory, the development of ecosystem science would never have reached the point of today. Some ideas are presented about the importance that concept such as energy, entropy, exergy information and none equilibrium have in the analysis of processes taking place in ecosystems

  20. Embodiment Analysis for Greenhouse Gas Emissions by Chinese Economy Based on Global Thermodynamic Potentials

    Directory of Open Access Journals (Sweden)

    Lijie Wang

    2011-11-01

    Full Text Available This paper considers the Global Thermodynamic Potential (GTP indicator to perform a unified assessment of greenhouse gas (GHG emissions, and to systematically reveal the emission embodiment in the production, consumption, and international trade of the Chinese economy in 2007 as the most recent year available with input-output table and updated inventory data. The results show that the estimated total direct GHG emissions by the Chinese economy in 2007 amount to 10,657.5 Mt CO2-eq by the GTPs with 40.6% from CH4 emissions in magnitude of the same importance as CO2 emissions. The five sectors of Electric Power/Steam and Hot Water Production and Supply, Smelting and Pressing of Ferrous and Nonferrous Metals, Nonmetal Mineral Products, Agriculture, and Coal Mining and Dressing, are responsible for 83.3% of the total GHG emissions with different emission structures. The demands of coal and coal-electricity determine the structure of emission embodiment to an essential extent. The Construction sector holds the top GHG emissions embodied in both domestic production and domestic consumption. The GHG emission embodied in gross capital formation is more than those in other components of final demand characterized by extensive investment and limited household consumption. China is a net exporter of embodied GHG emissions, with a remarkable share of direct emission induced by international trade, such as textile products, industrial raw materials, and primary machinery and equipment products exports. The fractions of CH4 in the component of embodied GHG emissions in the final demand are much greater than those fractions calculated by the Global Warming Potentials, which highlight the importance of CH4 emissions for the case of China and indicate the essential effect of CH4 emissions on global climate change. To understand the full context to achieve GHG emission mitigation, this study provides a new insight to address China’s GHG emissions status and

  1. Fundamental Research in Engineering Education. Development of Concept Questions and Inquiry-Based Activities in Thermodynamics and Heat Transfer: An Example for Equilibrium vs. Steady-State

    Science.gov (United States)

    Vigeant, Margot; Prince, Michael; Nottis, Katharyn

    2011-01-01

    This study examines the use of inquiry-based instruction to promote the understanding of critical concepts in thermodynamics and heat transfer. Significant research shows that students frequently enter our courses with tightly held misconceptions about the physical world that are not effectively addressed through traditional instruction. Students'…

  2. Galactic bulges from Hubble Space Telescope NICMOS observations : Global scaling relations

    NARCIS (Netherlands)

    Balcells, Marc; Graham, Alister W.; Peletier, Reynier F.

    2007-01-01

    We investigate bulge and disk scaling relations using a volume-corrected sample of early-to intermediate-type disk galaxies in which, importantly, the biasing flux from additional nuclear components has been modeled and removed. Structural parameters are obtained from a seeing-convolved, bulge +

  3. Chemical abundances and dust in planetary nebulae in the Galactic bulge

    NARCIS (Netherlands)

    Gutenkunst, S.; Bernard-Salas, J.; Pottasch, S. R.; Sloan, G. C.; Houck, J. R.

    2008-01-01

    We present mid-infrared Spitzer spectra of 11 planetary nebulae in the Galactic bulge. We derive argon, neon, sulfur, and oxygen abundances for them using mainly infrared line fluxes combined with some optical line fluxes from the literature. Due to the high extinction toward the bulge, the infrared

  4. THE SHAPE OF THE LUMINOSITY PROFILES OF BULGES OF SPIRAL GALAXIES

    NARCIS (Netherlands)

    ANDREDAKIS, YC; PELETIER, RF; BALCELLS, M

    1995-01-01

    Using a 2D generalization of Kent's model-independent decomposition method, we extract the K-band light profiles of the bulges of a sample of field galaxies with morphological types ranging from S0 to Sbc. We then examine the shape of the bulge profiles, by means of fitting a seeing-convolved power

  5. X-ray bursters and the X-ray sources of the galactic bulge

    International Nuclear Information System (INIS)

    Lewin, W.H.G.; Joss, P.C.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge

    1981-01-01

    In this article we shall discuss the observed X-ray, optical, infrared and radio properties of the galactic bulge sources, with an emphasis on those that produce type I X-ray bursts. There is persuasive evidence that these burst sources and many other galactic bulge sources are neutron stars in low-mass, close-binary stellar systems. (orig./WL)

  6. Acid-base equilibrium. A thermodynamic study of formation and stability of the Bi-2223 phase

    International Nuclear Information System (INIS)

    Xi, Z.; Zhou, L.

    1993-01-01

    A general acid-base equilibrium theory was proposed to explain the formation and stability of the Bi-2223 phase based on the Lewis acid base theory and principle of metallurgical physical chemistry. The acid-base nature of oxide was defined according to the electrostatic force between cation and oxygen anion. A series of experimental facts were systematically explained based on the theory: substitution of Bi for Ca in the Pb-free 2223 phase, and the effect of substitution of the high-valent cation for Bi 3+ ; oxygen-pressure atmosphere, and the heat-schocking technique on the formation and stability of the 2223 phase. 14 refs., 2 tabs

  7. Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon

    Science.gov (United States)

    Qin, Chuan; Zhong, Shijie; Phillips, Roger

    2018-02-01

    First recognized by Laplace over two centuries ago, the Moon's present tidal-rotational bulges are significantly larger than hydrostatic predictions. They are likely relics of a former hydrostatic state when the Moon was closer to the Earth and had larger bulges, and they were established when stresses in a thickening lunar lithosphere could maintain the bulges against hydrostatic adjustment. We formulate the first dynamically self-consistent model of this process and show that bulge formation is controlled by the relative timing of lithosphere thickening and lunar orbit recession. Viable solutions indicate that lunar bulge formation was a geologically slow process lasting several hundred million years, that the process was complete about 4 Ga when the Moon-Earth distance was less than 32 Earth radii, and that the Earth in Hadean was significantly less dissipative to lunar tides than during the last 4 Gyr, possibly implying a frozen hydrosphere due to the fainter young Sun.

  8. The Composition of the Bulge Globular Cluster NGC 6273

    Science.gov (United States)

    Pilachowski, C. A.; Johnson, C. I.; Rich, R. M.; Caldwell, N.; Mateo, M.; Bailey, J. I.; Crane, J. D.

    2017-03-01

    Observations of red giants in the Bulge globular cluster NGC 6273 with the Michigan/Magellan Fiber System (M2FS) mounted on the Nasmuth-East port of the Magellan-Clay 6.5-m telescope at the Las Campanas Observatory reveal a spread in metallicity. Members have been confirmed with radial velocity. NGC 6273 has at least two populations separated by 0.2-0.3 dex in [Fe/H]. The sodium and aluminum abundances are correlated while the magnesium and aluminum abundances are anti-correlated. The cluster also shows a rise in the abundance of the s-process element lanthanum with [Fe/H] similar to other massive clusters. The cluster contains a possible third population depleted in most elements by 0.3 dex.

  9. Monitoring and Mapping the Galactic Bulge (core Program)

    Science.gov (United States)

    Both neutron star and black hole binary transients are providing some of the most exciting RXTE science, and fortunately many are concentrated in the galactic bulge region. We propose to continue our twice weekly PCA scans of the region, which cover about 500 sq deg. The observations will be sensitive to new sources at the ~1 mCrab level (a factor of 10-60 more sensitive than the ASM in the region). We have had success finding new sources and new types of variability, including three millisecond pulsars, and new increased solid angle will improve the chances of finding more in the final RXTE years. We will continue efforts to search for variability in new and known sources. Companion follow-up proposals would be triggered by the results.

  10. A TWO-PHASE SCENARIO FOR BULGE ASSEMBLY IN {Lambda}CDM COSMOLOGIES

    Energy Technology Data Exchange (ETDEWEB)

    Obreja, A.; Dominguez-Tenreiro, R.; Brook, C. [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, E-28049 Cantoblanco Madrid (Spain); Martinez-Serrano, F. J.; Domenech-Moral, M.; Serna, A. [Departamento de Fisica y Arquitectura de Computadores, Universidad Miguel Hernandez, E-03202 Elche (Spain); Molla, M. [Departamento de Investigacion Basica, CIEMAT, E-28040 Madrid (Spain); Stinson, G., E-mail: aura.obreja@uam.es [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany)

    2013-01-20

    We analyze and compare the bulges of a sample of L {sub *} spiral galaxies in hydrodynamical simulations in a cosmological context, using two different codes, P-DEVA and GASOLINE. The codes regulate star formation in very different ways, with P-DEVA simulations inputting low star formation efficiency under the assumption that feedback occurs on subgrid scales, while the GASOLINE simulations have feedback that drives large-scale outflows. In all cases, the marked knee shape in mass aggregation tracks, corresponding to the transition from an early phase of rapid mass assembly to a later slower one, separates the properties of two populations within the simulated bulges. The bulges analyzed show an important early starburst resulting from the collapse-like fast phase of mass assembly, followed by a second phase with lower star formation, driven by a variety of processes such as disk instabilities and/or mergers. Classifying bulge stellar particles identified at z = 0 into old and young according to these two phases, we found bulge stellar sub-populations with distinct kinematics, shapes, stellar ages, and metal contents. The young components are more oblate, generally smaller, more rotationally supported, with higher metallicity and less alpha-element enhanced than the old ones. These results are consistent with the current observational status of bulges, and provide an explanation for some apparently paradoxical observations, such as bulge rejuvenation and metal-content gradients observed. Our results suggest that bulges of L {sub *} galaxies will generically have two bulge populations that can be likened to classical and pseudo-bulges, with differences being in the relative proportions of the two, which may vary due to galaxy mass and specific mass accretion and merger histories.

  11. Chemodynamical modelling of the galactic bulge and bar

    Science.gov (United States)

    Portail, Matthieu; Wegg, Christopher; Gerhard, Ortwin; Ness, Melissa

    2017-09-01

    We present the first self-consistent chemodynamical model fitted to reproduce data for the galactic bulge, bar and inner disc. We extend the Made-to-Measure method to an augmented phase-space including the metallicity of stars, and show its first application to the bar region of the Milky Way. Using data from the ARGOS and APOGEE (DR12) surveys, we adapt the recent dynamical model from Portail et al. to reproduce the observed spatial and kinematic variations as a function of metallicity, thus allowing the detailed study of the 3D density distributions, kinematics and orbital structure of stars in different metallicity bins. We find that metal-rich stars with [Fe/H] ≥ -0.5 are strongly barred and have dynamical properties that are consistent with a common disc origin. Metal-poor stars with [Fe/H] ≤ -0.5 show strong kinematic variations with metallicity, indicating varying contributions from the underlying stellar populations. Outside the central kpc, metal-poor stars are found to have the density and kinematics of a thick disc while in the inner kpc, evidence for an extra concentration of metal-poor stars is found. Finally, the combined orbit distributions of all metallicities in the model naturally reproduce the observed vertex deviations in the bulge. This paper demonstrates the power of Made-to-Measure chemodynamical models, that when extended to other chemical dimensions will be very powerful tools to maximize the information obtained from large spectroscopic surveys such as APOGEE, GALAH and MOONS.

  12. Thermodynamic Considerations of Contamination by Alloying Elements of Remelted End-of-Life Nickel- and Cobalt-Based Superalloys

    Science.gov (United States)

    Lu, Xin; Matsubae, Kazuyo; Nakajima, Kenichi; Nakamura, Shinichiro; Nagasaka, Tetsuya

    2016-06-01

    Cobalt and nickel are high-value commodity metals and are mostly used in the form of highly alloyed materials. The alloying elements used may cause contamination problems during recycling. To ensure maximum resource efficiency, an understanding of the removability of these alloying elements and the controllability of some of the primary alloying elements is essential with respect to the recycling of end-of-life (EoL) nickel- and cobalt-based superalloys by remelting. In this study, the distribution behaviors of approximately 30 elements that are usually present in EoL nickel- and cobalt-based superalloys in the solvent metal (nickel, cobalt, or nickel-cobalt alloy), oxide slag, and gas phases during the remelting were quantitatively evaluated using a thermodynamic approach. The results showed that most of the alloying elements can be removed either in the slag phase or into the gas phase. However, the removal of copper, tin, arsenic, and antimony by remelting is difficult, and they remain as tramp elements during the recycling. On the other hand, the distribution tendencies of iron, molybdenum, and tungsten can be controlled by changing the remelting conditions. To increase the resource efficiency of recycling, preventing contamination by the tramp elements and identifying the alloying compositions of EoL superalloys are significantly essential, which will require the development of efficient prior alloy-sorting systems and advanced separation technologies.

  13. Quantum mechanics based force field for carbon (QMFF-Cx) validated to reproduce the mechanical and thermodynamics properties of graphite

    Science.gov (United States)

    Pascal, Tod A.; Karasawa, Naoki; Goddard, William A.

    2010-10-01

    As assemblies of graphene sheets, carbon nanotubes, and fullerenes become components of new nanotechnologies, it is important to be able to predict the structures and properties of these systems. A problem has been that the level of quantum mechanics practical for such systems (density functional theory at the PBE level) cannot describe the London dispersion forces responsible for interaction of the graphene planes (thus graphite falls apart into graphene sheets). To provide a basis for describing these London interactions, we derive the quantum mechanics based force field for carbon (QMFF-Cx) by fitting to results from density functional theory calculations at the M06-2X level, which demonstrates accuracies for a broad class of molecules at short and medium range intermolecular distances. We carried out calculations on the dehydrogenated coronene (C24) dimer, emphasizing two geometries: parallel-displaced X (close to the observed structure in graphite crystal) and PD-Y (the lowest energy transition state for sliding graphene sheets with respect to each other). A third, eclipsed geometry is calculated to be much higher in energy. The QMFF-Cx force field leads to accurate predictions of available experimental mechanical and thermodynamics data of graphite (lattice vibrations, elastic constants, Poisson ratios, lattice modes, phonon dispersion curves, specific heat, and thermal expansion). This validates the use of M06-2X as a practical method for development of new first principles based generations of QMFF force fields.

  14. Solution phase thermodynamics of strong electrolytes based on ionic concentrations, hydration numbers and volumes of dissolved entities

    Czech Academy of Sciences Publication Activity Database

    Heyrovská, Raji

    2013-01-01

    Roč. 24, č. 6 (2013), s. 1895-1901 ISSN 1040-0400 Institutional support: RVO:68081707 Keywords : Solution thermodynamics * Aqueous electrolytes * Partial electrolytic dissociation Subject RIV: BO - Biophysics Impact factor: 1.900, year: 2013

  15. Premelting, solid-fluid equilibria, and thermodynamic properties in the high density region based on the Lennard-Jones potential

    Science.gov (United States)

    Köster, Andreas; Mausbach, Peter; Vrabec, Jadran

    2017-10-01

    The Lennard-Jones potential is used to study the high density fluid and face centered cubic solid state region, including solid-fluid equilibria. Numerous thermodynamic properties are considered, elucidating the behavior of matter in this poorly studied region. The present molecular simulation results are extensively compared to the latest and most accurate equation of state models for fluid and solid phases. It is shown that current models do not cover the thermodynamics of the system adequately near the solid-fluid phase transition. Furthermore, thermodynamic stability is analyzed, indicating that published solid-fluid coexistence data may not be correct at high temperatures. Particular attention is paid to the premelting zone, a range of states close to the melting line, which is characterized by strong variations of several thermodynamic properties. Because the underlying microscopic mechanisms are not yet fully understood, it is hoped that these data may contribute to the development of a theoretical framework for describing premelting effects.

  16. Andromeda chained to the box - dynamical models for M31: bulge and bar

    Science.gov (United States)

    Blaña Díaz, Matias; Wegg, Christopher; Gerhard, Ortwin; Erwin, Peter; Portail, Matthieu; Opitsch, Michael; Saglia, Roberto; Bender, Ralf

    2017-04-01

    Andromeda is our nearest neighbouring disc galaxy and a prime target for detailed modelling of the evolutionary processes that shape galaxies. We analyse the nature of M31's triaxial bulge with an extensive set of N-body models, which include box/peanut (B/P) bulges as well as initial classical bulges (ICBs). Comparing with Infrared Array Camera (IRAC) 3.6 μm data, only one model matches simultaneously all the morphological properties of M31's bulge, and requires an ICB and a B/P bulge with 1/3 and 2/3 of the total bulge mass, respectively. We find that our pure B/P bulge models do not show concentrations high enough to match the Sérsic index (n) and the effective radius of M31's bulge. Instead, the best model requires an ICB component with mass MICB = 1.1 × 1010 M⊙ and 3D half-mass radius rhalfICB = 0.53 kpc (140 arcsec). The B/P bulge component has a mass of MB/P = 2.2 × 1010 M⊙ and a half-mass radius of rhalfB/P = 1.3 kpc (340 arcsec). The model's B/P bulge extends to rB/P = 3.2 kpc (840 arcsec) in the plane of the disc as does M31's bulge. In this composite bulge model, the ICB component explains the velocity dispersion drop observed in the centre within R < 190 pc (50 arcsec), while the B/P bulge component reproduces the observed rapid rotation and the kinematic twist of the observed zero velocity line. This model's pattern speed is Ωp = 38 km s-1 kpc-1, placing corotation at rcor = 5.8 kpc (1500 arcsec). The outer Lindblad resonance (OLR) is then at rOLR = 10.4 kpc, near the 10 kpc ring of M31, suggesting that this structure may be related to the bar's OLR. By comparison with an earlier snapshot, we estimate that M31's thin bar extends to rbarthin ˜ 4.0 kpc (1000 arcsec) in the disc plane, and in projection extends to Rbarthin ˜ 2.3 kpc (600 arcsec).

  17. Computing Thermodynamic And Transport Properties

    Science.gov (United States)

    Mcbride, B.; Gordon, Sanford

    1993-01-01

    CET89 calculates compositions in chemical equilibrium and properties of mixtures of any chemical system for which thermodynamic data available. Provides following options: obtains chemical-equilibrium compositions and corresponding thermodynamic mixture properties for assigned thermodynamic states; calculates dilute-gas transport properties of complex chemical mixtures; obtains Chapman-Jouguet detonation properties for gaseous mixtures; calculates properties of incident and reflected shocks in terms of assigned velocities; and calculates theoretical performance of rocket for both equilibrium and frozen compositions during expansion. Rocket performance based on optional models of finite or infinite area combustor.

  18. An Improved Mnemonic Device for Thermodynamic Relations

    Directory of Open Access Journals (Sweden)

    Younghun Kim

    2016-12-01

    Full Text Available An improved mnemonic device for thermodynamic relations between state variables and potentials was proposed in the form of a thermodynamic circle. Based on separating the Born square into an inner square (T, P, V, and S and an outer circle (G, A, U, and H, relations such as Legendre transforms, Maxwell equations, equations to compute variables, and differential equations for thermodynamic variables can be recalled easily. The thermodynamic circle has a cross-arrow at its center and can be used to intuitively determine the sign of all thermodynamic relations.

  19. Galactic bulge population II Cepheids in the VVV survey: period-luminosity relations and a distance to the Galactic centre

    Science.gov (United States)

    Bhardwaj, A.; Rejkuba, M.; Minniti, D.; Surot, F.; Valenti, E.; Zoccali, M.; Gonzalez, O. A.; Romaniello, M.; Kanbur, S. M.; Singh, H. P.

    2017-09-01

    Context. Multiple stellar populations of different ages and metallicities reside in the Galactic bulge that trace its structure and provide clues to its formation and evolution. Aims: We present the near-infrared observations of population II Cepheids in the Galactic bulge from VISTA Variables in the Vía Láctea (VVV) survey. The JHKs photometry together with optical data from Optical Gravitational Lensing Experiment (OGLE) survey provide an independent estimate of the distance to the Galactic centre. The old, metal-poor and low-mass population II Cepheids are also investigated as useful tracers for the structure of the Galactic bulge. Methods: We identify 340 population II Cepheids in the VVV survey Galactic bulge catalogue based on their match with the OGLE-III Catalogue. The single-epoch JH and multi-epoch Ks observations complement the accurate periods and optical (VI) mean-magnitudes from OGLE. The sample consisting of BL Herculis and W Virginis subtypes is used to derive period-luminosity relations after correcting mean-magnitudes for the extinction. Our Ks-band period-luminosity relation, Ks = -2.189(0.056) [log (P)-1] + 11.187(0.032), is consistent with published work for BL Herculis and W Virginis variables in the Large Magellanic Cloud. Results: We present a combined OGLE-III and VVV catalogue with periods, classification, mean magnitudes, and extinction for 264 Galactic bulge population II Cepheids that have good-quality Ks-band light curves. The absolute magnitudes for population II Cepheids and RR Lyraes calibrated using Gaia and Hubble Space Telescope parallaxes, together with calibrated magnitudes for Large Magellanic Cloud population II Cepheids, are used to obtain a distance to the Galactic centre, R0 = 8.34 ± 0.03(stat.) ± 0.41(syst.), which changes by with different extinction laws. While noting the limitation of small number statistics, we find that the present sample of population II Cepheids in the Galactic bulge shows a nearly spheroidal

  20. Is bioethanol a sustainable energy source? An energy-, exergy-, and emergy-based thermodynamic system analysis

    NARCIS (Netherlands)

    Liao, Wenjie; Heijungs, Reinout; Huppes, Gjalt

    2011-01-01

    Biofuels are widely seen as substitutes for fossil fuels to offset the imminent decline of oil production and to mitigate the emergent increase in GHG emissions. This view is, however, based on too simple an analysis, focusing on only one piece in the whole mosaic of the complex biofuel

  1. The melting points of MgO up to 4 TPa predicted based on ab initio thermodynamic integration molecular dynamics.

    Science.gov (United States)

    Taniuchi, Takashi; Tsuchiya, Taku

    2018-03-21

    The melting curve of MgO is extended up to 4 TPa, corresponding to the Jovian core pressure, based on the one-step thermodynamic integration method implemented on ab initio molecular dynamics. The calculated melting temperatures are 3100 and 16 000 K at 0 and 500 GPa, respectively, which are consistent with previous experimental results, and 20 600 K at 3900 GPa, which is inconsistent with a recent experimental extrapolation, which implies the molten Jovian core. A quite small Clapeyron slope ([Formula: see text]) of [Formula: see text] is found at 3900 GPa due to comparable densities of the liquid and B2 phases under extreme compression. The Mg-O coordination number in the liquid phase is saturated at around 7.5 above 1 TPa and remains smaller than that in the B2 phase (8) even at 4 TPa, suggesting no density crossover between liquid and crystal and thus no further denser crystalline phases. Dynamical properties (atomic diffusivity and viscosity) are also investigated along the melting curve to understand these behaviors in greater detail.

  2. Thermodynamic simulation analysis of a multifuel CHP plant basing on the technological diagram of Avedøre unit 2

    Science.gov (United States)

    Ziębik, Andrzej; Szegda, Damian; Qvale, Bjørn; Elmegaard, Brian

    2010-03-01

    The paper presents the results of a simulative thermodynamic analysis of a multifuel CHP plant basing on the technological diagram of Avedøre 2. Calculations have been carried out for the operation of Avedøre 2 plant in the district heating mode. Several variants of simulation have been considered, determined by the choice of operation of the respective plants, viz. main boiler fired with natural gas, main and biomass boiler, main boiler and GT plant, joint operation of the main and biomass boiler and GT plant, main boiler (fired with heavy fuel oil or/and wood chips) and biomass boiler and GT plant. For each variants a diagram of iso-fuel curves has been developed, illustrating the variability of useful effects (power output and district heat) at various loads of the CHP steam part. In case of the variant in which the main boiler and GT are in operation with natural gas as fuel the exemplary energy indices were determined.

  3. Development of thermodynamically-based models for simulation of hydrogeochemical processes coupled to channel flow processes in abandoned underground mines

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, N.A., E-mail: natalie.kruse@ncl.ac.uk [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Younger, P.L. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2009-07-15

    Accurate modeling of changing geochemistry in mine water can be an important tool in post-mining site management. The Pollutant Sources and Sinks in Underground Mines (POSSUM) model and Pollutant Loadings Above Average Pyrite Influenced Geochemistry POSSUM (PLAYING POSSUM) model were developed using object-oriented programming techniques to simulate changing geochemistry in abandoned underground mines over time. The conceptual model was created to avoid significant simplifying assumptions that decrease the accuracy and defensibility of model solutions. POSSUM and PLAYING POSSUM solve for changes in flow rate and depth of flow using a finite difference hydrodynamics model then, subsequently, solve for geochemical changes at distinct points along the flow path. Geochemical changes are modeled based on a suite of 28 kinetically controlled mineral weathering reactions. Additional geochemical transformations due to reversible sorption, dissolution and precipitation of acid generating salts and mineral precipitation are also simulated using simplified expressions. Contaminant transport is simulated using a novel application of the Random-Walk method. By simulating hydrogeochemical changes with a physically and thermodynamically controlled model, the 'state of the art' in post-mining management can be advanced.

  4. The melting points of MgO up to 4 TPa predicted based on ab initio thermodynamic integration molecular dynamics

    Science.gov (United States)

    Taniuchi, Takashi; Tsuchiya, Taku

    2018-03-01

    The melting curve of MgO is extended up to 4 TPa, corresponding to the Jovian core pressure, based on the one-step thermodynamic integration method implemented on ab initio molecular dynamics. The calculated melting temperatures are 3100 and 16 000 K at 0 and 500 GPa, respectively, which are consistent with previous experimental results, and 20 600 K at 3900 GPa, which is inconsistent with a recent experimental extrapolation, which implies the molten Jovian core. A quite small Clapeyron slope (dT/dP ) of 0.0+/- 0.5 is found at 3900 GPa due to comparable densities of the liquid and B2 phases under extreme compression. The Mg–O coordination number in the liquid phase is saturated at around 7.5 above 1 TPa and remains smaller than that in the B2 phase (8) even at 4 TPa, suggesting no density crossover between liquid and crystal and thus no further denser crystalline phases. Dynamical properties (atomic diffusivity and viscosity) are also investigated along the melting curve to understand these behaviors in greater detail.

  5. A thermodynamical and structural study on the complexation of trivalent lanthanides with a polycarboxylate based concrete superplasticizer.

    Science.gov (United States)

    Fröhlich, Daniel R; Maiwald, Martin M; Taube, Franziska; Plank, Johann; Panak, Petra J

    2017-03-21

    The complexation of trivalent lanthanides with a commercial polycarboxylate based concrete superplasticizer (Glenium® 51) is investigated using different spectroscopic techniques. Time-resolved laser fluorescence spectroscopy (TRLFS) in combination with a charge neutralization model is used to determine temperature dependent conditional stability constants (log β'(T)) for the complexation of Eu(iii) with Glenium® 51 in 0.1 mol kg -1 NaCl solution in the temperature range of 20-90 °C. Only one complex species is observed, and log β'(T) (given in kg per mol eq) shows a very slight increase with temperature from 7.5 to 7.9. The related conditional molar reaction enthalpy (Δ r H' m ) and entropy (Δ r S' m ) obtained using the Van't Hoff equation show that the complexation reaction is slightly endothermic and entropy driven. The thermodynamic investigations are complemented by structural data for complexes formed with Gd(iii) or Tb(iii) and Glenium® 51 using extended X-ray absorption fine structure (EXAFS) spectroscopy. The results imply a non-chelate coordination of the trivalent metals through approximately three carboxylic functions of the polycarboxylate comb polymer which are attached predominantly in a bidentate fashion to the lanthanide under the given experimental conditions.

  6. Thermodynamic and Structure Guided Design of Statin Based Inhibitors of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase

    Energy Technology Data Exchange (ETDEWEB)

    Sarver, Ronald W.; Bills, Elizabeth; Bolton, Gary; Bratton, Larry D.; Caspers, Nicole L.; Dunbar, James B.; Harris, Melissa S.; Hutchings, Richard H.; Kennedy, Robert M.; Larsen, Scott D.; Pavlovsky, Alexander; Pfefferkorn, Jeffrey A.; Bainbridge, Graeme (Pfizer)

    2008-10-02

    Clinical studies have demonstrated that statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) inhibitors, are effective at lowering mortality levels associated with cardiovascular disease; however, 2--7% of patients may experience statin-induced myalgia that limits compliance with a treatment regimen. High resolution crystal structures, thermodynamic binding parameters, and biochemical data were used to design statin inhibitors with improved HMGR affinity and therapeutic index relative to statin-induced myalgia. These studies facilitated the identification of imidazole 1 as a potent (IC{sub 50} = 7.9 nM) inhibitor with excellent hepatoselectivity (>1000-fold) and good in vivo efficacy. The binding of 1 to HMGR was found to be enthalpically driven with a {Delta}H of -17.7 kcal/M. Additionally, a second novel series of bicyclic pyrrole-based inhibitors was identified that induced order in a protein flap of HMGR. Similar ordering was detected in a substrate complex, but has not been reported in previous statin inhibitor complexes with HMGR.

  7. Simultaneous determination of thermodynamic and kinetic parameters of aminopolycarbonate complexes of cobalt(II) and nickel(II) based on isothermal titration calorimetry data.

    Science.gov (United States)

    Tesmar, Aleksandra; Wyrzykowski, Dariusz; Muñoz, Eva; Pilarski, Bogusław; Pranczk, Joanna; Jacewicz, Dagmara; Chmurzyński, Lech

    2017-04-01

    The influence of the different side chain residues on the thermodynamic and kinetic parameters for complexation reactions of the Co 2 + and Ni 2 + ions has been investigated by using the isothermal titration calorimetry (ITC) technique supported by potentiometric titration data. The study was concerned with the 2 common tripodal aminocarboxylate ligands, namely, nitrilotriacetic acid and N-(2-hydroxyethyl) iminodiacetic acid. Calorimetric measurements (ITC) were run in the 2-(N-morpholino)ethanesulfonic acid hydrate (2-(N-morpholino) ethanesulfonic acid), piperazine-N,N'-bis(2-ethanesulfonic acid), and dimethylarsenic acid buffers (0.1 mol L -1 , pH 6) at 298.15 K. The quantification of the metal-buffer interactions and their incorporation into the ITC data analysis enabled to obtain the pH-independent and buffer-independent thermodynamic parameters (K, ΔG, ΔH, and ΔS) for the reactions under study. Furthermore, the kinITC method was applied to obtain kinetic information on complexation reactions from the ITC data. Correlations, based on kinetic and thermodynamic data, between the kinetics of formation of Co 2 + and Ni 2 + complexes and their thermodynamic stabilities are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Thermodynamics of a post combustion hydrate-based carbon dioxide capture process

    International Nuclear Information System (INIS)

    Ben Attouche Sfaxi, I.

    2011-07-01

    Hydrates selectivity towards carbon dioxide is offering a promising route for carbon dioxide removal from flue gases. Hydrate-based CO 2 capture process could substitute amine facilities widely implemented in gas treatment plants but suffering from oxidative degradation problems and high energy demand. In the framework of this thesis, we focus on phase equilibria that are involved in such process. Experimental dissociation conditions for clathrate hydrates of carbon dioxide and nitrogen, in the presence of some promoting molecules (Tetrahydrofuran, Tetrabutyl ammonium bromide and Tetrabutyl ammonium Fluoride ) are reported in the experimental section of this work. The data generated in this work along with literature data are compared to the model predictions. The developed model is based on the Cubic Plus Association (CPA) equation of state (EoS) for fluid phases combined to the van der Waals and Platteeuw's theory for the hydrate phase. (author)

  9. Thoria-based nuclear fuels thermophysical and thermodynamic properties, fabrication, reprocessing, and waste management

    CERN Document Server

    Bharadwaj, S R

    2013-01-01

    This book presents the state of the art on thermophysical and thermochemical properties, fabrication methodologies, irradiation behaviours, fuel reprocessing procedures, and aspects of waste management for oxide fuels in general and for thoria-based fuels in particular. The book covers all the essential features involved in the development of and working with nuclear technology. With the help of key databases, many of which were created by the authors, information is presented in the form of tables, figures, schematic diagrams and flow sheets, and photographs. This information will be useful for scientists and engineers working in the nuclear field, particularly for design and simulation, and for establishing the technology. One special feature is the inclusion of the latest information on thoria-based fuels, especially on the use of thorium in power generation, as it has less proliferation potential for nuclear weapons. Given its natural abundance, thorium offers a future alternative to uranium fuels in nuc...

  10. Effect of an upstream bulge configuration on film cooling with and without mist injection.

    Science.gov (United States)

    Wang, Jin; Li, Qianqian; Sundén, Bengt; Ma, Ting; Cui, Pei

    2017-12-01

    To meet the economic requirements of power output, the increased inlet temperature of modern gas turbines is above the melting point of the material. Therefore, high-efficient cooling technology is needed to protect the blades from the hot mainstream. In this study, film cooling was investigated in a simplified channel. A bulge located upstream of the film hole was numerically investigated by analysis of the film cooling effectiveness distribution downstream of the wall. The flow distribution in the plate channel is first presented. Comparing with a case without bulge, different cases with bulge heights of 0.1d, 0.3d and 0.5d were examined with blowing ratios of 0.5 and 1.0. Cases with 1% mist injection were also included in order to obtain better cooling performance. Results show that the bulge configuration located upstream the film hole makes the cooling film more uniform, and enhanceslateral cooling effectiveness. Unlike other cases, the configuration with a 0.3d-height bulge shows a good balance in improving the downstream and lateral cooling effectiveness. Compared with the case without mist at M = 0.5, the 0.3d-height bulge with 1% mist injection increases lateral average effectiveness by 559% at x/d = 55. In addition, a reduction of the thermal stress concentration can be obtained by increasing the height of the bulge configuration. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Bulging Behavior of Thin-walled Welded Low Carbon Steel Tubes

    Directory of Open Access Journals (Sweden)

    XIE Wen-cai

    2017-01-01

    Full Text Available In order to investigate the deformation behaviour of welded tubes during hydraulic bulging process,the hydraulic bulging tests of thin-walled welded low carbon steel tubes (STKM11A were conducted on the tube hydroformability testing unit.The thickness distribution,profiles of bulging area and the strain distribution were all obtained.Results show that the thickness reduction of weld zone is just 2.4%-5.5% while its effective strain is just 0.05-0.10,which is very small and negligible compared with the parent material and means that just the geometric position of weld zone is changed with the continuous bulging.The thinnest points are located on the both sides of weld seam symmetrically and the angle between the thinnest point and weld seam is about 30°,at which the necking has been occurred.When the length of bulging area increases,the fracture pressure,the thickness reduction and the ultimate expansion ratio all decrease,and the profile of the bulging area gradually steps away from the elliptical model which is powerless for the ratio of length to diameter up to 2.0.Moreover,the strain state of the tube is transformed from biaxial tension to plane strain state with the increasing length of bulging area,on the basis of this the forming limit diagram of welded STKM11A steel tubes can be established.

  12. New 3,4-diaminobenzoic acid Schiff base compounds and their complexes: synthesis, characterization and thermodynamics.

    Science.gov (United States)

    Mohammadi, Khosro; Niad, Mahmood; Jafari, Tahereh

    2014-03-25

    Some new tetradentate Schiff base ligands (H3L) were prepared via condensation of 3,4-diaminobenzoic acid with 2-hydroxybenzaldehyde derivatives, such as 3,4-bis((E)-2,4-dihydroxybenzylideneamino)benzoic acid (H3L(1)), 3,4-bis((E)-2-hydroxy-3-methoxybenzylideneamino)benzoic acid (H3L(2)) and 3,4-bis((E)-5-bromo-2-hydroxybenzylideneamino)benzoic acid (H3L(4)). Additionally, a tetradentate Schiff base ligand 3,4-bis((E)-2-hydroxybenzylideneamino)benzoic acid (H3L(3)) and its complexes were synthesized. Their metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) were prepared in good yields from the reaction of the ligands with the corresponding metal acetate. They were characterized based on IR, (1)H NMR, Mass spectroscopy and UV-Vis spectroscopy. Also, the formation constants of the complexes were measured by UV-Vis spectroscopic titration at constant ionic strength 0.1M (NaClO4), at 25 °C in dimethylformamide (DMF) as a solvent. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  13. Morpho-kinematic properties of field S0 bulges in the CALIFA survey

    Science.gov (United States)

    Méndez-Abreu, J.; Aguerri, J. A. L.; Falcón-Barroso, J.; Ruiz-Lara, T.; Sánchez-Menguiano, L.; de Lorenzo-Cáceres, A.; Costantin, L.; Catalán-Torrecilla, C.; Zhu, L.; Sánchez-Blazquez, P.; Florido, E.; Corsini, E. M.; Wild, V.; Lyubenova, M.; van de Ven, G.; Sánchez, S. F.; Bland-Hawthorn, J.; Galbany, L.; García-Benito, R.; García-Lorenzo, B.; González Delgado, R. M.; López-Sánchez, A. R.; Marino, R. A.; Márquez, I.; Ziegler, B.; Califa Collaboration

    2018-02-01

    We study a sample of 28 S0 galaxies extracted from the integral field spectroscopic (IFS) survey Calar Alto Legacy Integral Field Area. We combine an accurate two-dimensional (2D) multicomponent photometric decomposition with the IFS kinematic properties of their bulges to understand their formation scenario. Our final sample is representative of S0s with high stellar masses (M⋆/M⊙ > 1010). They lay mainly on the red sequence and live in relatively isolated environments similar to that of the field and loose groups. We use our 2D photometric decomposition to define the size and photometric properties of the bulges, as well as their location within the galaxies. We perform mock spectroscopic simulations mimicking our observed galaxies to quantify the impact of the underlying disc on our bulge kinematic measurements (λ and v/σ). We compare our bulge corrected kinematic measurements with the results from Schwarzschild dynamical modelling. The good agreement confirms the robustness of our results and allows us to use bulge deprojected values of λ and v/σ. We find that the photometric (n and B/T) and kinematic (v/σ and λ) properties of our field S0 bulges are not correlated. We demonstrate that this morpho-kinematic decoupling is intrinsic to the bulges and it is not due to projection effects. We conclude that photometric diagnostics to separate different types of bulges (disc-like versus classical) might not be useful for S0 galaxies. The morpho-kinematics properties of S0 bulges derived in this paper suggest that they are mainly formed by dissipational processes happening at high redshift, but dedicated high-resolution simulations are necessary to better identify their origin.

  14. Thermodynamics of disaggregated polymer composites based on nanosized powders of Ni and NiO

    Directory of Open Access Journals (Sweden)

    N. S. Volodina

    2015-03-01

    Full Text Available Technique to obtain disaggregated composites with uniform distribution of the Ni nanoparticles in a polymer matrix was developed on the example of epoxy resin. Disaggregated and aggregated composites based on butyl methacrylate copolymer with 5 wt% methacrylic acid and Ni and NiO nanoparticles were obtained. Enthalpies of mixing the components compositions in a wide range of compositions were defined using isothermal calorimetry. Parameters adhesive interaction at the interface and glassy polymer structure changes were calculated. The influence of the chemical nature of nanosized filler on interfacial energy was found.

  15. Thermodynamical Phase Noise in Oscillators Based on L-C Resonators

    OpenAIRE

    Izpura Torres, José Ignacio; Malo Gomez, Javier

    2012-01-01

    Using a new Admittance-based model for electrical noise able to handle Fluctuations and Dissipations of electrical energy, we explain the phase noise of oscillators that use feedback around L-C resonators. We show that Fluctuations produce the Line Broadening of their output spectrum around its mean frequency f0 and that the Pedestal of phase noise far from f0 comes from Dissipations modified by the feedback electronics. The charge noise power 4FkT/R C2/s that disturbs the otherwise periodic ...

  16. Synthesis, crystal structure and thermodynamic properties of a new praseodymium Schiff-base complex

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chuan-Hua, E-mail: lichuanhua0526@126.com [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan (China); Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China); Song, Xiang-Zhi, E-mail: xzsong@csu.edu.cn [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, Hunan (China); Jiang, Jian-Hong [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China); Gu, Hui-Wen [State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, Hunan (China); Tao, Li-Ming; Yang, Ping; Li, Xu; Xiao, Sheng-Xiong; Yao, Fei-Hong; Liu, Wen-Qi; Xie, Jin-Qi; Peng, Meng-Na; Pan, Lan; Wu, Xi-Bin; Jiang, Chao; Wang, Song; Xu, Man-Fen [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China); Li, Qiang-Guo, E-mail: liqiangguo@163.com [Hunan Provincial Key Laboratory of Xiangnan Rare-Precious Metals Compounds and Applications, Department of Chemistry and Life Science, Xiangnan University, Chenzhou 423000, Hunan (China)

    2014-04-01

    Highlights: • A new mononuclear Schiff base praseodymium complex was synthesized. • Based on Hess's law, thermochemical cycles of two reactions were designed. • The dissolution enthalpies were measured by a solution–reaction calorimeter. • The standard molar enthalpy of formation of the complex was calculated. - Abstract: The title complex [Pr(H{sub 2}vanen)(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}·NO{sub 3}] was synthesized reacting of Valen Schiff-base ligand [H{sub 2}vanen = N,N′-ethylene-bis(3-methoxysalicylideneimine)] and Pr(NO{sub 3}){sub 3}·6H{sub 2}O in ethanol at 60 °C. The complex was crystallized in the monoclinic crystal system with space group P21/c. The coordination polyhedron of Pr(III) ion was consisted of two bidentate nitrate ions, two molecules of water and one ligand which coordinated through oxygen atoms of the two phenolic and methoxy groups. After designing two reasonable thermochemical cycles according to Hess's law, the calorimetric experiments were conducted using isoperibol solution–reaction calorimeter at a constant temperature of 298.15 K. The standard molar enthalpy changes of two reactions were determined to be Δ{sub r}H{sub m}{sup θ}(1a)=−(51.94±1.26) kJ mol{sup −1} and Δ{sub r}H{sub m}{sup θ}(1b)=−(8.62±1.34) kJ mol{sup −1}. Then the standard molar enthalpies of formation of the ligand and the title complex were calculated to be Δ{sub f}H{sub m}{sup θ} [H{sub 2}vanen(s), 298.15 K] = −(517.75 ± 2.36) kJ mol{sup −1} and Δ{sub f}H{sub m}{sup θ} [Pr(H{sub 2}vanen)(NO{sub 3}){sub 2}(H{sub 2}O){sub 2}·NO{sub 3} (s), 298.15 K] = −(2454.8 ± 2.7) kJ mol{sup −1}, respectively. The rationality of two thermochemical cycles was verified by UV spectra and refractive indexes.

  17. ALMA observations of molecular absorption in four directions toward the Galactic bulge

    Science.gov (United States)

    Liszt, H.; Gerin, M.

    2018-02-01

    Context. Alma Cycle 3 observations serendipitously showed strong absorption from diffuse molecular gas in the Galactic bulge at -200 km s-1 51(3σ) for the bulge gas toward J1744 and 58 ± 9 and 64 ± 4 for the disk gas toward J1717 and J1744, respectively, all well above the value of 20-25 typical of the central molecular zone. Conclusions: The kinematics and chemistry of the bulge gas observed toward J1744 more nearly resemble that of gas in the Milky Way disk than in the central molecular zone.

  18. Bulge formation and necking in a polymer tube under dynamic expansion

    DEFF Research Database (Denmark)

    Lindgreen, Britta; Tvergaard, Viggo; Needleman, Alan

    2008-01-01

    Bulging and necking in long thin polymer tubes subjected to increasing internal pressure are analysed numerically. The polymer is characterized by a finite strain elastic-viscoplastic constitutive relation and the calculations are carried out using a dynamic finite element program. Two types...... of imposed loading are prescribed: (i) a pressure that increases linearly with time and (ii) a change in enclosed volume that increases linearly with time. For both loading conditions, an axisymmetric bulge develops on the tube followed by necking in the bulge. The necks propagate in both the circumferential...

  19. Magnetic and thermodynamic properties of the Pr-based ferromagnet PrGe2-δ

    Science.gov (United States)

    Matsumoto, Keisuke T.; Morioka, Naoya; Hiraoka, Koichi

    2018-03-01

    We investigated the magnetization, M, and specific heat, C, of ThSi2-type PrGe2-δ. A polycrystalline sample of PrGe2-δ was prepared by arc-melting. Magnetization divided by magnetic field, M / B, increased sharply and C showed a clear jump at the Curie temperature, TC, of 14.6 K; these results indicate that PrGe2-δ ordered ferromagnetically. The magnetic entropy at TC reached R ln 3, indicating a quasi-triplet crystalline electric field (CEF) ground state. The maximum value of magnetic entropy change was 11.5 J/K kg with a field change of 7 T, which is comparable to those of other right rare-earth based magnetocaloric materials. This large magnetic entropy change was attributed to the quasi-triplet ground state of the CEF.

  20. Thermodynamic study of the surface of liquid mixtures containing pyridinium-based ionic liquids and alkanols

    International Nuclear Information System (INIS)

    García-Mardones, Mónica; Cea, Pilar; Gascón, Ignacio; Lafuente, Carlos

    2014-01-01

    Highlights: • Surface tensions of a pyridinium ionic liquid with an alkanol have been determined. • From experimental data surface tension deviations have been obtained and correlated. • Relative adsorptions of alkanol at the (air + liquid) interface were also calculated. • The relative adsorptions were found positive in all the mixtures. - Abstract: Surface tension for seven binary mixtures containing a pyridinium-based ionic liquid (1-propylpyridinium tetrafluoroborate, 1-butylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium tetrafluoroborate, or 1-butyl-4-methylpyridinium) and a short chain alkanol (methanol or ethanol) were determined at the temperatures: (293.15, 303.15, 313.15, and 323.15) K. From these data, the surface tension deviations were calculated. These deviations were correlated using a Redlich–Kister polynomial expansion. Moreover, relative adsorptions of alkanol at the (air + liquid) interface were calculated from the Gibbs isotherm

  1. Thermodynamics of Radiation Modes

    Science.gov (United States)

    Pina, Eduardo; de la Selva, Sara Maria Teresa

    2010-01-01

    We study the equilibrium thermodynamics of the electromagnetic radiation in a cavity of a given volume and temperature. We found three levels of description, the thermodynamics of one mode, the thermodynamics of the distribution of frequencies in a band by summing over the frequencies in it and the global thermodynamics by summing over all the…

  2. Study of thermodynamic and transport properties of phosphonium-based ionic liquids

    International Nuclear Information System (INIS)

    Deive, Francisco J.; Rivas, Miguel A.; Rodríguez, Ana

    2013-01-01

    Highlights: ► Physical and transport properties of three hydrophilic phoshonium ILs were determined. ► Experimental density, viscosity, refractive index and speed of sound were correlated. ► Predictive equations were successfully employed to predict density of the three ILs. -- Abstract: In this work, the experimental values of density, speed of sound, refractive index and dynamic viscosity have been obtained from T = (293.15 to 343.15) K for the three phosphonium-based ionic liquids: tributyl methyl phoshponium methylsulfate (P 4441 C 1 SO 4 ), tributyl ethyl phosphonium diethylphosphate (P 4442 (C 2 ) 2 PO 4 ) and tributyl octyl phosphonium chloride (P 4448 Cl). The isentropic compressibility has been calculated by means of the Laplace equation from the experimental speed of sound results for the three ionic liquids at different temperatures. Density, speed of sound, refractive index and isentropic compressibility have been correlated by polynomial equations. The Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, Newton and modified Eykman equations were the empirical models used to correlate satisfactorily the relationship between the densities and refractive indices of the ionic liquids selected. The temperature dependence of the experimental dynamic viscosities for the ionic liquids selected can be described by an Arrhenius-like law and by VFT equations. The Riedel, Narsimham, Bradford–Thodos, Yen–Woods, Rackett, Spencer–Danner, Gunn–Yamada, Hankinson–Thomson (COSTALD model), VSY, VSD, MH and LGM equations were employed to predict the densities of the pure ionic liquids

  3. Modelling and simulation of liquid-vapor phase transition in compressible flows based on thermodynamical equilibrium

    International Nuclear Information System (INIS)

    Faccanoni, Gloria; Kokh, Samuel; Allaire, Gregoire

    2012-01-01

    In the present work we investigate the numerical simulation of liquid-vapor phase change in compressible flows. Each phase is modeled as a compressible fluid equipped with its own equation of state (EOS). We suppose that inter-phase equilibrium processes in the medium operate at a short time-scale compared to the other physical phenomena such as convection or thermal diffusion. This assumption provides an implicit definition of an equilibrium EOS for the two-phase medium. Within this framework, mass transfer is the result of local and instantaneous equilibria between both phases. The overall model is strictly hyperbolic. We examine properties of the equilibrium EOS and we propose a discretization strategy based on a finite-volume relaxation method. This method allows to cope with the implicit definition of the equilibrium EOS, even when the model involves complex EOS's for the pure phases. We present two-dimensional numerical simulations that shows that the model is able to reproduce mechanism such as phase disappearance and nucleation. (authors)

  4. mathFISH, a web tool that uses thermodynamics-based mathematical models for in silico evaluation of oligonucleotide probes for fluorescence in situ hybridization.

    Science.gov (United States)

    Yilmaz, L Safak; Parnerkar, Shreyas; Noguera, Daniel R

    2011-02-01

    Mathematical models of RNA-targeted fluorescence in situ hybridization (FISH) for perfectly matched and mismatched probe/target pairs are organized and automated in web-based mathFISH (http://mathfish.cee.wisc.edu). Offering the users up-to-date knowledge of hybridization thermodynamics within a theoretical framework, mathFISH is expected to maximize the probability of success during oligonucleotide probe design.

  5. Mathematical foundations of thermodynamics

    CERN Document Server

    Giles, R; Stark, M; Ulam, S

    2013-01-01

    Mathematical Foundations of Thermodynamics details the core concepts of the mathematical principles employed in thermodynamics. The book discusses the topics in a way that physical meanings are assigned to the theoretical terms. The coverage of the text includes the mechanical systems and adiabatic processes; topological considerations; and equilibrium states and potentials. The book also covers Galilean thermodynamics; symmetry in thermodynamics; and special relativistic thermodynamics. The book will be of great interest to practitioners and researchers of disciplines that deal with thermodyn

  6. Dynamical manifestations of quantum chaos: correlation hole and bulge

    Science.gov (United States)

    Torres-Herrera, E. J.; Santos, Lea F.

    2017-10-01

    A main feature of a chaotic quantum system is a rigid spectrum where the levels do not cross. We discuss how the presence of level repulsion in lattice many-body quantum systems can be detected from the analysis of their time evolution instead of their energy spectra. This approach is advantageous to experiments that deal with dynamics, but have limited or no direct access to spectroscopy. Dynamical manifestations of avoided crossings occur at long times. They correspond to a drop, referred to as correlation hole, below the asymptotic value of the survival probability and to a bulge above the saturation point of the von Neumann entanglement entropy and the Shannon information entropy. By contrast, the evolution of these quantities at shorter times reflects the level of delocalization of the initial state, but not necessarily a rigid spectrum. The correlation hole is a general indicator of the integrable-chaos transition in disordered and clean models and as such can be used to detect the transition to the many-body localized phase in disordered interacting systems. This article is part of the themed issue 'Breakdown of ergodicity in quantum systems: from solids to synthetic matter'.

  7. Positron Transport and Annihilation in the Galactic Bulge

    Directory of Open Access Journals (Sweden)

    Fiona Helen Panther

    2018-03-01

    Full Text Available The annihilation of positrons in the Milky Way Galaxy has been observed for ∼50 years; however, the production sites of these positrons remains hard to identify. The observed morphology of positron annihilation gamma-rays provides information on the annihilation sites of these Galactic positrons. It is understood that the positrons responsible for the annihilation signal originate at MeV energies. The majority of sources of MeV positrons occupy the star-forming thin disk of the Milky Way. If positrons propagate far from their sources, we must develop accurate models of positron propagation through all interstellar medium (ISM phases in order to reveal the currently uncertain origin of these Galactic positrons. On the other hand, if positrons annihilate close to their sources, an alternative source of MeV positrons with a distribution that matches the annihilation morphology must be identified. In this work, I discuss the various models that have been developed to understand the origin of the 511 keV line from the direction of the Galactic bulge, and the propagation of positrons in the ISM.

  8. Chemical Equilibrium as Balance of the Thermodynamic Forces

    OpenAIRE

    Zilbergleyt, B.

    2004-01-01

    The article sets forth comprehensive basics of thermodynamics of chemical equilibrium as balance of the thermodynamic forces. Based on the linear equations of irreversible thermodynamics, De Donder definition of the thermodynamic force, and Le Chatelier's principle, new thermodynamics of chemical equilibrium offers an explicit account for multiple chemical interactions within the system. Basic relations between energetic characteristics of chemical transformations and reaction extents are bas...

  9. Thermodynamic investigation on acid-base equilibria of deferiprone and deferasirox at different ionic strengths and various temperatures

    International Nuclear Information System (INIS)

    Boroujeni, Hadi Chahiyan; Gharib, Farrokh

    2016-01-01

    Highlights: • Protonation constants of deferiprone and deferasirox were determined at different ionic strengths and various temperatures. • Enthalpy, entropy, and Gibbs energy changes of protonation were determined at different ionic strengths of NaCl using modified van’t Hoff method. • The dependence of protonation constants of the drugs on ionic strength was modelled by seven different approaches at 25.0 °C. - Abstract: The acid–base equilibria of two iron chelating drugs, deferiprone (DFP) and deferasirox (DFX), have been studied in aqueous solution using potentiometric and spectrophotometric methods at different ionic strengths (0.100–3.200 and 0.100–1.548 mol kg −1 NaCl for DFP and DFX, respectively) and various temperatures (293.15–310.15 K). Owing to the low solubility of DFX in aqueous medium, in this case, the experiments were performed in aqueous solution of 30% (v/v) DMSO. The results showed that by increasing of temperature, all the protonation constants of the both drugs decreased indicating exothermic reactions. The thermodynamic functions of protonation including ΔG°, ΔH° and ΔS° at the mean temperature (301.15 K) were determined at different ionic strengths using a modified van’t Hoff equation. The relative contributions of enthalpy (ζ H ) and entropy (ζ TS ) were also calculated for the protonation steps of the drugs. The dependence of protonation constants of DFP and DFX on ionic strength was modelled by seven different approaches at 298.15 K. The log K o values (at zero ionic strength) of the drugs were also determined. Finally, the experimental protonation constants of DFP were compared with the literature data and comparison has been made and discussed between the different models.

  10. Material characterization of Inconel 718 from free bulging test at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Joon Tae; Yoon, Jong Hoon; Lee, Ho Sung [Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Youn, Sung Kie [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2012-07-15

    Macroscopic superplastic behavior of metallic or non metallic materials is usually represented by the strain rate sensitivity, and it can be determined by tensile tests in uniaxial stress state and bulging tests in multi axial stress state, which is the actual hot forming process. And macroscopic behavior of Non SPF grade materials could be described in a similar way as that of superplastic materials, including strain hardening, cavity and so on. In this study, the material characterization of non SPF grade Inconel 718 has been carried out to determine the material parameters for flow stress throughout free bulging test under constant temperature. The measured height of bulged plate during the test was used for estimation of strain rate sensitivity, strain hardening index and cavity volume fraction with the help of numerical analysis. The bulged height obtained from the simulation showed good agreement with the experimental findings. The effects of strain hardening and cavity volume fraction factor for flow stress were also compared.

  11. Incidence and Risk Factors for Parastomal Bulging in Patients with Ileostomy or Colostomy

    DEFF Research Database (Denmark)

    Andersen, Rune M; Klausen, Tobias W; Danielsen, Anne K

    2018-01-01

    AIM: To investigate incidence and risk factors for parastomal bulging, a clinically important complication, in patients with an ileostomy or colostomy. METHOD: The Danish Stoma Database Capital Region prospectively collects data on patients with a stoma up to a year after surgery. Stoma care nurses...... clinically assessed the main outcome, parastomal bulging. We linked data from the Stoma Database to data from the Danish Anaesthesia Database. Cumulative incidence of parastomal bulging over the first year was calculated with death and stoma reversal as competing risks. Risk factors were investigated using...... with cancer, inflammatory bowel disease was associated with a lower risk of parastomal bulging, and diverticulitis was associated with a higher risk. Peristomal mesh and stomas placed through a separate incision were associated with a reduction in risk. There was neither increased nor decreased risk...

  12. Galactic bulge preferred over dark matter for the Galactic centre gamma-ray excess

    Science.gov (United States)

    Macias, Oscar; Gordon, Chris; Crocker, Roland M.; Coleman, Brendan; Paterson, Dylan; Horiuchi, Shunsaku; Pohl, Martin

    2018-03-01

    An anomalous gamma-ray excess emission has been found in the Fermi Large Area Telescope data1 covering the centre of the Galaxy2,3. Several theories have been proposed for this `Galactic centre excess'. They include self-annihilation of dark-matter particles4, an unresolved population of millisecond pulsars5, an unresolved population of young pulsars6, or a series of burst events7. Here, we report on an analysis that exploits hydrodynamical modelling to register the position of interstellar gas associated with diffuse Galactic gamma-ray emission. We find evidence that the Galactic centre excess gamma rays are statistically better described by the stellar over-density in the Galactic bulge and the nuclear stellar bulge, rather than a spherical excess. Given its non-spherical nature, we argue that the Galactic centre excess is not a dark-matter phenomenon but rather associated with the stellar population of the Galactic bulge and the nuclear bulge.

  13. The discovery of thermodynamics

    Science.gov (United States)

    Weinberger, Peter

    2013-07-01

    Based on the idea that a scientific journal is also an "agora" (Greek: market place) for the exchange of ideas and scientific concepts, the history of thermodynamics between 1800 and 1910 as documented in the Philosophical Magazine Archives is uncovered. Famous scientists such as Joule, Thomson (Lord Kelvin), Clausius, Maxwell or Boltzmann shared this forum. Not always in the most friendly manner. It is interesting to find out, how difficult it was to describe in a scientific (mathematical) language a phenomenon like "heat", to see, how long it took to arrive at one of the fundamental principles in physics: entropy. Scientific progress started from the simple rule of Boyle and Mariotte dating from the late eighteenth century and arrived in the twentieth century with the concept of probabilities. Thermodynamics was the driving intellectual force behind the industrial revolution, behind the enormous social changes caused by this revolution. The history of thermodynamics is a fascinating story, which also gives insights into the mechanism that seem to govern science.

  14. ARGOS - III. Stellar populations in the Galactic bulge of the Milky Way

    Science.gov (United States)

    Ness, M.; Freeman, K.; Athanassoula, E.; Wylie-de-Boer, E.; Bland-Hawthorn, J.; Asplund, M.; Lewis, G. F.; Yong, D.; Lane, R. R.; Kiss, L. L.

    2013-04-01

    We present the metallicity results from the ARGOS spectroscopic survey of the Galactic bulge. Our aim is to understand the formation of the Galactic bulge: did it form via mergers, as expected from Λ cold dark matter theory, or from disc instabilities, as suggested by its boxy/peanut shape, or both? Our stars are mostly red clump giants, which have a well-defined absolute magnitude from which distances can be determined. We have obtained spectra for 28 000 stars at a spectral resolution of R = 11 000. From these spectra, we have determined stellar parameters and distances to an accuracy of -0.5 are part of the boxy/peanut bar/bulge. We associate the lower metallicity stars ([Fe/H] -0.5, we find two discrete populations: (i) stars with [Fe/H] ≈ -0.25 which provide a roughly constant fraction of the stars in the latitude interval b = -5° to -10°, and (ii) a kinematically colder, more metal-rich population with mean [Fe/H] ≈ +0.15 which is more prominent closer to the plane. The changing ratio of these components with latitude appears as a vertical abundance gradient of the bulge. We attribute both of these bulge components to instability-driven bar/bulge formation from the thin disc. We associate the thicker component with the stars of the early less metal-rich thin disc, and associate the more metal-rich population concentrated to the plane with the colder more metal-rich stars of the early thin disc, similar to the colder and younger more metal-rich stars seen in the thin disc in the solar neighbourhood today. We do not exclude a weak underlying classical merger-generated bulge component, but see no obvious kinematic association of any of our bulge stars with such a classical bulge component. The clear spatial and kinematic separation of the two bulge populations (i) and (ii) makes it unlikely that any significant merger event could have affected the inner regions of the Galaxy since the time when the bulge-forming instabilities occurred.

  15. Elemental abundances in AGB stars and the formation of the Galactic bulge

    Directory of Open Access Journals (Sweden)

    Wood P.R.

    2012-02-01

    Full Text Available We obtained high-resolution near-IR spectra of 45 AGB stars located in the Galactic bulge. The aim of the project is to determine key elemental abundances in these stars to help constrain the formation history of the bulge. A further aim is to link the photospheric abundances to the dust species found in the winds of the stars. Here we present a progress report of the analysis of the spectra.

  16. A Catalog of Edge-on Disk Galaxies: From Galaxies with a Bulge to Superthin Galaxies

    OpenAIRE

    Kautsch, S. J.; Grebel, E. K.; Barazza, F. D.; Gallagher, J. S.

    2005-01-01

    The formation and evolution of disk-dominated galaxies is difficult to explain, yet these objects exist. We therefore embarked on a study aimed at a better understanding of these enigmatic objects. We used data from the SDSS DR1 in order to identify edge-on galaxies with disks in a uniform, reproducible, automated fashion. We identified 3169 edge-on disk galaxies, which we subdivided into disk galaxies with bulge, intermediate types, and simple disk galaxies without any obvious bulge componen...

  17. Thermodynamic characteristics of the acid-base equilibria of taurine in aqueous solutions, according to calorimetry data

    Science.gov (United States)

    Gridchin, S. N.; Shekhanov, R. F.; Pyreu, D. F.

    2015-02-01

    Enthalpies of the neutralization and protonation of taurine (HL) are measured by direct calorimetry at 298.15 K and ionic strengths of 0.3, 0.5, and 1.0 (KNO3). The standard thermodynamic characteristics of HL protolytic equilibria are calculated.

  18. Self-assembly thermodynamics of pH-responsive amino-acid-based polymers with a nonionic surfactant

    Czech Academy of Sciences Publication Activity Database

    Bogomolova, Anna; Keller, S.; Klingler, J.; Sedlak, M.; Rak, D.; Šturcová, Adriana; Hrubý, Martin; Štěpánek, Petr; Filippov, Sergey K.

    2014-01-01

    Roč. 30, č. 38 (2014), s. 11307-11318 ISSN 0743-7463 R&D Projects: GA MŠk(CZ) LH14292 Grant - others:AV ČR(CZ) M200501201 Program:M Institutional support: RVO:61389013 Keywords : polymer * surfactant * thermodynamics Subject RIV: CC - Organic Chemistry Impact factor: 4.457, year: 2014

  19. A sub-grid, mixture-fraction-based thermodynamic equilibrium model for gas phase combustion in FIRETEC: development and results

    Science.gov (United States)

    M. M. Clark; T. H. Fletcher; R. R. Linn

    2010-01-01

    The chemical processes of gas phase combustion in wildland fires are complex and occur at length-scales that are not resolved in computational fluid dynamics (CFD) models of landscape-scale wildland fire. A new approach for modelling fire chemistry in HIGRAD/FIRETEC (a landscape-scale CFD wildfire model) applies a mixture– fraction model relying on thermodynamic...

  20. QSPR models based on molecular mechanics and quantum chemical calculations. 2. Thermodynamic properties of alkanes, alcohols, polyols, and ethers

    DEFF Research Database (Denmark)

    Dyekjær, Jane Dannow; Jonsdottir, Svava Osk

    2003-01-01

    Quantitative Structure-Property Relationship (QSPR) models for prediction of various thermodynamic properties of simple organic compounds have been developed. A number of new descriptors are proposed and used alongside with descriptors available within the Codessa program. An important feature in...

  1. Thermodynamic Property Surfaces for Adsorption of R507A, R134a, and n -Butane on Pitch-Based Carbonaceous Porous Materials

    KAUST Repository

    Chakraborty, Anutosh

    2010-10-01

    The thermodynamic property surfaces of R507A, R134a, and n-butane on pitch-based carbonaceous porous material (Maxsorb III) are developed from rigorous classical thermodynamics and experimentally measured adsorption isotherm data. These property fields enable us to compute the entropy, enthalpy, internal energy, and heat of adsorption as a function of pressure, temperature, and the amount of adsorbate. The entropy and enthalpy maps are necessary for the analysis of adsorption cooling cycle and gas storage. We have shown here that it is possible to plot an adsorption cooling cycle on the temperature-entropy (T-s) and enthalpy-uptake (h-x) maps. Copyright © Taylor and Francis Group, LLC 2010.

  2. A Simple, fast, and accurate thermodynamic-based approach for transfer and prediction of GC retention times between columns and instruments Part II: Estimation of target column geometry.

    Science.gov (United States)

    Hou, Siyuan; Stevenson, Keisean A J M; Harynuk, James J

    2018-03-25

    The transfer of thermodynamic parameters governing retention of a molecule in gas chromatography from a reference column to a target column is a difficult problem. Successful transfer demands a mechanism whereby the column geometries of both columns can be determined with high accuracy. This is the second part in a series of three papers. In Part I of this work we introduced a new approach to determine the actual effective geometry of a reference column and thermodynamic-based parameters of a suite of compounds on the column. Part II, presented here, illustrates the rapid estimation of the effective inner diameter (or length) and the effective phase ratio of a target column. The estimation model based on the principle of least squares; a fast Quasi-Newton optimization algorithm was developed to provide adequate computational speed. The model and optimization algorithm were tested and validated using simulated and experimental data. This study, together with the work in Parts I and III, demonstrates a method that improves the transferability of thermodynamic models of gas chromatography retention between gas chromatography columns. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process

    Directory of Open Access Journals (Sweden)

    Pablo Araujo Granda

    2016-01-01

    Full Text Available Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4+, NO3−, NO2−, N2 to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc. MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience.

  4. Modeling the Non-Equilibrium Process of the Chemical Adsorption of Ammonia on GaN(0001) Reconstructed Surfaces Based on Steepest-Entropy-Ascent Quantum Thermodynamics.

    Science.gov (United States)

    Kusaba, Akira; Li, Guanchen; von Spakovsky, Michael R; Kangawa, Yoshihiro; Kakimoto, Koichi

    2017-08-15

    Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3Ga-H and N ad -H + Ga-H on a 2 × 2 unit cell) is investigated using steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic-ensemble based, first-principles framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium where the state evolution is a combination of reversible and irreversible dynamics. SEAQT is an ideal choice to handle this problem on a first-principles basis since the chemical adsorption process starts from a highly non-equilibrium state. A result of the analysis shows that the probability of adsorption on 3Ga-H is significantly higher than that on N ad -H + Ga-H. Additionally, the growth temperature dependence of these adsorption probabilities and the temperature increase due to the heat of reaction is determined. The non-equilibrium thermodynamic modeling applied can lead to better control of the MOVPE process through the selection of preferable reconstructed surfaces. The modeling also demonstrates the efficacy of DFT-SEAQT coupling for determining detailed non-equilibrium process characteristics with a much smaller computational burden than would be entailed with mechanics-based, microscopic-mesoscopic approaches.

  5. First-principles calculation of thermodynamic stability of acids and bases under pH environment: A microscopic pH theory

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Kwiseon; Zhang, S. B.

    2012-04-01

    Despite being one of the most important thermodynamic variables, pH has yet to be incorporated into first-principles thermodynamics to calculate stability of acidic and basic solutes in aqueous solutions. By treating the solutes as defects in homogeneous liquids, we formulate a first-principles approach to calculate their formation energies under proton chemical potential, or pH, based on explicit molecular dynamics. The method draws analogy to first-principle calculations of defect formation energies under electron chemical potential, or Fermi energy, in semiconductors. From this, we propose a simple pictorial representation of the general theory of acid-base chemistry. By performing first-principles molecular dynamics of liquid water models with solutes, we apply the formulation to calculate formation energies of various neutral and charged solutes such as H+, OH-, NH3, NH4+, HCOOH, and HCOO- in water. The deduced auto-dissociation constant of water and the difference in the pKa values of NH3 and HCOOH show good agreement with known experimental values. Our first-principles approach can be further extended and applied to other bio- and electro-chemical molecules such as amino acids and redox reaction couples that could exist in aqueous environments to understand their thermodynamic stability.

  6. A density functional reactivity theory (DFRT) based approach to understand the effect of symmetry of fullerenes on the kinetic, thermodynamic and structural aspects of carbon NanoBuds

    International Nuclear Information System (INIS)

    Sarmah, Amrit; Roy, Ram Kinkar

    2016-01-01

    Highlights: • Kinetic and thermodynamic aspects of the interaction between fullerene (C 32 ) and SWCNT using CDASE scheme. • Role of symmetry of fullerenes as well as the site of covalent attachment to the SWCNT in the structural stability of the NanoBud structure. • Increase in the fullerene symmetry improves the relative stability of hybrid NanoBud structure. - Abstract: In the present study, we have rationalized the effect of variation in the symmetry of relatively smaller fullerene (C 32 ) on the mode of its interaction with semi-conducting Single-Walled Carbon Nanotubes (SWCNTs) in the process of formation of stable hybrid carbon NanoBuds. Thermodynamic and kinetic parameters, along with the charge transfer values associated with the interaction between fullerene and SWCNTs, have been evaluated using an un-conventional and computationally cost–effective method based on density functional reactivity theory (DFRT). In addition to this, conventional DFT based studies are also performed to substantiate the growth of NanoBud structures formed by the interaction between fullerene and SWCNTs. The findings of the present study suggest that the kinetic, thermodynamic and structural aspects of hybrid carbon NanoBuds are significantly influenced by both the symmetry of C 32 fullerene and its site of covalent attachment to the SWCNT.

  7. Thermodynamic tables to accompany Modern engineering thermodynamics

    CERN Document Server

    Balmer, Robert T

    2011-01-01

    This booklet is provided at no extra charge with new copies of Balmer's Modern Engineering Thermodynamics. It contains two appendices. Appendix C contains 40 thermodynamic tables, and Appendix D consists of 6 thermodynamic charts. These charts and tables are provided in a separate booklet to give instructors the flexibility of allowing students to bring the tables into exams. The booklet may be purchased separately if needed.

  8. Formation of the bulge of Iapetus through long-wavelength folding of the lithosphere

    Science.gov (United States)

    Kay, Jonathan P.; Dombard, Andrew J.

    2018-03-01

    Previous models that attempted to explain the formation of the pronounced oblate shape of Iapetus suggested that it was a preserved rotational bulge. These models found that heating was provided by short-lived radioactive isotopes that decayed rapidly and allowed the excess flattening of the lithosphere to be locked in by a thickening lithosphere, but placed severe timing constraints on the formation of Iapetus and its bulge. Here, we show that finite element simulations with an elastic-viscous-plastic rheology indicate it is possible to form the bulge through long-wavelength folding of the lithosphere of Iapetus during an epoch of contraction combined with a latitudinal surface temperature gradient. In contrast to models of a frozen rotational bulge, heat generated by long-lived radioactive isotopes warms the interior, which causes porosity loss and forces Iapetus to compact by ∼10%. Our simulations are most successful when there is a 30 K temperature difference between the pole and the equator. Tectonic growth of the bulge is not sensitive to the time scale over which the moon contracts, and lithospheric thickness primarily controls whether a fold can form, not fold wavelength. In addition, long term simulations show that when no stress is applied, the mechanical lithosphere is strong enough to support the bulge, with negligible relaxation over billion year time scales.

  9. A HIGH-VELOCITY BULGE RR LYRAE VARIABLE ON A HALO-LIKE ORBIT

    International Nuclear Information System (INIS)

    Kunder, Andrea; Storm, J.; Rich, R. M.; Hawkins, K.; Poleski, R.; Johnson, C. I.; Shen, J.; Li, Z.-Y.; Cordero, M. J.; Nataf, D. M.; Bono, G.; Walker, A. R.; Koch, A.; De Propris, R.; Udalski, A.; Szymanski, M. K.; Soszynski, I.; Pietrzynski, G.; Ulaczyk, K.; Wyrzykowski, Ł.

    2015-01-01

    We report on the RR Lyrae variable star, MACHO 176.18833.411, located toward the Galactic bulge and observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay, which has the unusual radial velocity of −372 ± 8 km s −1 and true space velocity of −482 ± 22 km s −1 relative to the Galactic rest frame. Located less than 1 kpc from the Galactic center and toward a field at (l, b) = (3, −2.5), this pulsating star has properties suggesting it belongs to the bulge RR Lyrae star population, yet a velocity indicating it is abnormal, at least with respect to bulge giants and red clump stars. We show that this star is most likely a halo interloper and therefore suggest that halo contamination is not insignificant when studying metal-poor stars found within the bulge area, even for stars within 1 kpc of the Galactic center. We discuss the possibility that MACHO 176.18833.411 is on the extreme edge of the bulge RR Lyrae radial velocity distribution, and also consider a more exotic scenario in which it is a runaway star moving through the Galaxy

  10. Spectroscopic decomposition of NGC 3521: unveiling the properties of the bulge and disc.

    Science.gov (United States)

    Coccato, Lodovico; Fabricius, Maximilian H.; Saglia, Roberto P.; Bender, Ralf; Erwin, Peter; Drory, Niv; Morelli, Lorenzo

    2018-03-01

    We study the kinematics and the stellar populations of the bulge and disc of the spiral galaxy NGC 3521. At each position in the field of view, we separate the contributions of the bulge and the disc from the total observed spectrum and study their kinematics, age, and metallicities independently. Their properties are clearly distinct: the bulge rotates more slowly, has a higher velocity dispersion, and is less luminous than the disc. We identify three main populations of stars in NGC 3521: old (≥7 Gyr), intermediate (≈ 3 Gyr), and young (≤1 Gyr). The mass and light of NGC 3521 are dominated by the intermediate stellar population. The youngest population contributes mostly to the disc component and its contribution increases with radius. We also study the luminosity-weighed properties of the stars in NGC 3521. Along the photometric major axis, we find: i) no age gradient for the stars in the bulge, and a negative age gradient for the stars in the disc; ii) negative metallicity gradients and sub-solar α-enhancement for both the bulge and the disc. We propose the following picture for the formation of NGC 3521: initial formation a long time ago (≥7 Gyr), followed by a second burst of star formation or a merger (≈ 3 Gyrs ago), which contributed predominantly to the mass-build up of the bulge. Recently (≤1 Gyr), the disc of NGC 3521 experienced an additional episode of star formation that started in the innermost regions.

  11. A HIGH-VELOCITY BULGE RR LYRAE VARIABLE ON A HALO-LIKE ORBIT

    Energy Technology Data Exchange (ETDEWEB)

    Kunder, Andrea; Storm, J. [Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Rich, R. M. [Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, CA 90095-1562 (United States); Hawkins, K. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Poleski, R. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Johnson, C. I. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Shen, J.; Li, Z.-Y. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Cordero, M. J. [Astronomisches Rechen-Institut: Zentrum für Astronomie, Mönchhofstr. 12-14, D-69120 Heidelberg (Germany); Nataf, D. M. [Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Bono, G. [Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma (Italy); Walker, A. R. [Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile); Koch, A. [Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, D-69117 Heidelberg (Germany); De Propris, R. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Turku (Finland); Udalski, A.; Szymanski, M. K.; Soszynski, I.; Pietrzynski, G.; Ulaczyk, K.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); and others

    2015-07-20

    We report on the RR Lyrae variable star, MACHO 176.18833.411, located toward the Galactic bulge and observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay, which has the unusual radial velocity of −372 ± 8 km s{sup −1} and true space velocity of −482 ± 22 km s{sup −1} relative to the Galactic rest frame. Located less than 1 kpc from the Galactic center and toward a field at (l, b) = (3, −2.5), this pulsating star has properties suggesting it belongs to the bulge RR Lyrae star population, yet a velocity indicating it is abnormal, at least with respect to bulge giants and red clump stars. We show that this star is most likely a halo interloper and therefore suggest that halo contamination is not insignificant when studying metal-poor stars found within the bulge area, even for stars within 1 kpc of the Galactic center. We discuss the possibility that MACHO 176.18833.411 is on the extreme edge of the bulge RR Lyrae radial velocity distribution, and also consider a more exotic scenario in which it is a runaway star moving through the Galaxy.

  12. The Bulging Behavior of Thick-Walled 6063 Aluminum Alloy Tubes Under Double-Sided Pressures

    Science.gov (United States)

    Cui, Xiao-Lei; Wang, Xiao-Song; Yuan, Shi-Jian

    2015-05-01

    To make further exploration on the deformation behavior of tube under double-sided pressures, the thick-walled 6063 aluminum alloy tubes with an outer diameter of 65 mm and an average thickness of 7.86 mm have been used to be bulged under the combined action of internal and external pressures. In the experiment, two ends of the thick-walled tubes were fixed using the tooth and groove match. Three levels of external pressure (0 MPa, 40 MPa, and 80 MPa), in conjunction with the internal pressure, were applied on the tube outside and inside simultaneously. The effect of external pressure on the bulging behavior of the thick-walled tubes, such as the limiting expansion ratio, the bulging zone profile, and the thickness distribution, has been investigated. It is shown that the limiting expansion ratio, the bulging zone profile, and the thickness distribution in the homogeneous bulging area are all insensitive to the external pressure. However, the external pressure can make the thick-walled tube achieve a thinner wall at the fracture area. It reveals that the external pressure can only improve the fracture limit of the thick-walled 6063 tubes, but it has very little effect on their homogeneous bulging behavior. It might be because the external pressure can only increase the magnitude of the hydrostatic pressure for the tube but has no effect on the Lode parameter.

  13. THE NUMBER OF TIDAL DWARF SATELLITE GALAXIES IN DEPENDENCE OF BULGE INDEX

    International Nuclear Information System (INIS)

    López-Corredoira, Martín; Kroupa, Pavel

    2016-01-01

    We show that a significant correlation (up to 5σ) emerges between the bulge index, defined to be larger for a larger bulge/disk ratio, in spiral galaxies with similar luminosities in the Galaxy Zoo 2 of the Sloan Digital Sky Survey and the number of tidal-dwarf galaxies in the catalog by Kaviraj et al. In the standard cold or warm dark matter cosmological models, the number of satellite galaxies correlates with the circular velocity of the dark matter host halo. In generalized gravity models without cold or warm dark matter, such a correlation does not exist, because host galaxies cannot capture infalling dwarf galaxies due to the absence of dark-matter-induced dynamical friction. However, in such models, a correlation is expected to exist between the bulge mass and the number of satellite galaxies because bulges and tidal-dwarf satellite galaxies form in encounters between host galaxies. This is not predicted by dark matter models in which bulge mass and the number of satellites are a priori uncorrelated because higher bulge/disk ratios do not imply higher dark/luminous ratios. Hence, our correlation reproduces the prediction of scenarios without dark matter, whereas an explanation is not found readily from the a priori predictions of the standard scenario with dark matter. Further research is needed to explore whether some application of the standard theory may explain this correlation

  14. Optimum design of dual pressure heat recovery steam generator using non-dimensional parameters based on thermodynamic and thermoeconomic approaches

    International Nuclear Information System (INIS)

    Naemi, Sanaz; Saffar-Avval, Majid; Behboodi Kalhori, Sahand; Mansoori, Zohreh

    2013-01-01

    The thermodynamic and thermoeconomic analyses are investigated to achieve the optimum operating parameters of a dual pressure heat recovery steam generator (HRSG), coupled with a heavy duty gas turbine. In this regard, the thermodynamic objective function including the exergy waste and the exergy destruction, is defined in such a way to find the optimum pinch point, and consequently to minimize the objective function by using non-dimensional operating parameters. The results indicated that, the optimum pinch point from thermodynamic viewpoint is 2.5 °C and 2.1 °C for HRSGs with live steam at 75 bar and 90 bar respectively. Since thermodynamic analysis is not able to consider economic factors, another objective function including annualized installation cost and annual cost of irreversibilities is proposed. To find the irreversibility cost, electricity price and also fuel price are considered independently. The optimum pinch point from thermoeconomic viewpoint on basis of electricity price is 20.6 °C (75 bar) and 19.2 °C (90 bar), whereas according to the fuel price it is 25.4 °C and 23.7 °C. Finally, an extensive sensitivity analysis is performed to compare optimum pinch point for different electricity and fuel prices. -- Highlights: ► Presenting thermodynamic and thermoeconomic optimization of a heat recovery steam generator. ► Defining an objective function consists of exergy waste and exergy destruction. ► Defining an objective function including capital cost and cost of irreversibilities. ► Obtaining the optimized operating parameters of a dual pressure heat recovery boiler. ► Computing the optimum pinch point using non-dimensional operating parameters

  15. Classical and statistical thermodynamics

    CERN Document Server

    Rizk, Hanna A

    2016-01-01

    This is a text book of thermodynamics for the student who seeks thorough training in science or engineering. Systematic and thorough treatment of the fundamental principles rather than presenting the large mass of facts has been stressed. The book includes some of the historical and humanistic background of thermodynamics, but without affecting the continuity of the analytical treatment. For a clearer and more profound understanding of thermodynamics this book is highly recommended. In this respect, the author believes that a sound grounding in classical thermodynamics is an essential prerequisite for the understanding of statistical thermodynamics. Such a book comprising the two wide branches of thermodynamics is in fact unprecedented. Being a written work dealing systematically with the two main branches of thermodynamics, namely classical thermodynamics and statistical thermodynamics, together with some important indexes under only one cover, this treatise is so eminently useful.

  16. Thermodynamic Analysis of Biodegradation Pathways

    Science.gov (United States)

    Finley, Stacey D.; Broadbelt, Linda J.

    2014-01-01

    Microorganisms provide a wealth of biodegradative potential in the reduction and elimination of xenobiotic compounds in the environment. One useful metric to evaluate potential biodegradation pathways is thermodynamic feasibility. However, experimental data for the thermodynamic properties of xenobiotics is scarce. The present work uses a group contribution method to study the thermodynamic properties of the University of Minnesota Biocatalysis/Biodegradation Database. The Gibbs free energies of formation and reaction are estimated for 914 compounds (81%) and 902 reactions (75%), respectively, in the database. The reactions are classified based on the minimum and maximum Gibbs free energy values, which accounts for uncertainty in the free energy estimates and a feasible concentration range relevant to biodegradation. Using the free energy estimates, the cumulative free energy change of 89 biodegradation pathways (51%) in the database could be estimated. A comparison of the likelihood of the biotransformation rules in the Pathway Prediction System and their thermodynamic feasibility was then carried out. This analysis revealed that when evaluating the feasibility of biodegradation pathways, it is important to consider the thermodynamic topology of the reactions in the context of the complete pathway. Group contribution is shown to be a viable tool for estimating, a priori, the thermodynamic feasibility and the relative likelihood of alternative biodegradation reactions. This work offers a useful tool to a broad range of researchers interested in estimating the feasibility of the reactions in existing or novel biodegradation pathways. PMID:19288443

  17. Microbial diversity arising from thermodynamic constraints

    Science.gov (United States)

    Großkopf, Tobias; Soyer, Orkun S

    2016-01-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments. PMID:27035705

  18. Microbial diversity arising from thermodynamic constraints.

    Science.gov (United States)

    Großkopf, Tobias; Soyer, Orkun S

    2016-11-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments.

  19. Polycyclic Aromatic Hydrocarbon Emission Toward the Galactic Bulge

    Science.gov (United States)

    Shannon, M. J.; Peeters, E.; Cami, J.; Blommaert, J. A. D. L.

    2018-03-01

    We examine polycyclic aromatic hydrocarbon (PAH), dust, and atomic/molecular emission toward the Galactic bulge using Spitzer Space Telescope observations of four fields: C32, C35, OGLE, and NGC 6522. These fields are approximately centered on (l, b) = (0.°0, 1.°0), (0.°0, ‑1.°0), (0.°4, ‑2.°4), and (1.°0, ‑3.°8), respectively. Far-infrared photometric observations complement the Spitzer/IRS spectroscopic data and are used to construct spectral energy distributions. We find that the dust and PAH emission are exceptionally similar between C32 and C35 overall, in part explained due to their locations—they reside on or near boundaries of a 7 Myr old Galactic outflow event and are partly shock-heated. Within the C32 and C35 fields, we identify a region of elevated Hα emission that is coincident with elevated fine-structure and [O IV] line emission and weak PAH feature strengths. We are likely tracing a transition zone of the outflow into the nascent environment. PAH abundances in these fields are slightly depressed relative to typical ISM values. In the OGLE and NGC 6522 fields, we observe weak features on a continuum dominated by zodiacal dust. SED fitting indicates that thermal dust grains in C32 and C35 have temperatures comparable to those of diffuse, high-latitude cirrus clouds. Little variability is detected in the PAH properties between C32 and C35, indicating that a stable population of PAHs dominates the overall spectral appearance. In fact, their PAH features are exceptionally similar to that of the M82 superwind, emphasizing that we are probing a local Galactic wind environment.

  20. MERGERS AND BULGE FORMATION IN ΛCDM: WHICH MERGERS MATTER?

    International Nuclear Information System (INIS)

    Hopkins, Philip F.; Bundy, Kevin; Wetzel, Andrew; Croton, Darren; Hernquist, Lars; Keres, Dusan; Younger, Joshua D.; Khochfar, Sadegh; Stewart, Kyle

    2010-01-01

    We use a suite of semi-empirical models to predict the galaxy-galaxy merger rate and relative contributions to bulge growth as a function of mass (both halo and stellar), redshift, and mass ratio. The models use empirical constraints on the halo occupation distribution, evolved forward in time, to robustly identify where and when galaxy mergers occur. Together with the results of high-resolution merger simulations, this allows us to quantify the relative contributions of mergers with different properties (e.g., mass ratios, gas fractions, redshifts) to the bulge population. We compare with observational constraints, and find good agreement. We also provide useful fitting functions and make public a code to reproduce the predicted merger rates and contributions to bulge mass growth. We identify several robust conclusions. (1) Major mergers dominate the formation and assembly of ∼L * bulges and the total spheroid mass density, but minor mergers contribute a non-negligible ∼30%. (2) This is mass dependent: bulge formation and assembly is dominated by more minor mergers in lower-mass systems. In higher-mass systems, most bulges originally form in major mergers near ∼L * , but assemble in increasingly minor mergers. (3) The minor/major contribution is also morphology dependent: higher B/T systems preferentially form in more major mergers, with B/T roughly tracing the mass ratio of the largest recent merger; lower B/T systems preferentially form in situ from minor mergers. (4) Low-mass galaxies, being gas-rich, require more mergers to reach the same B/T as high-mass systems. Gas-richness dramatically suppresses the absolute efficiency of bulge formation, but does not strongly influence the relative contribution of major versus minor mergers. (5) Absolute merger rates at fixed mass ratio increase with galaxy mass. (6) Predicted merger rates agree well with those observed in pair and morphology-selected samples, but there is evidence that some morphology

  1. Bifunctional cyclam-based ligands with phosphorus acid pendant moieties for radiocopper separation: thermodynamic and kinetic studies.

    Science.gov (United States)

    Paúrová, Monika; Havlíčková, Jana; Pospíšilová, Aneta; Vetrík, Miroslav; Císařová, Ivana; Stephan, Holger; Pietzsch, Hans-Jürgen; Hrubý, Martin; Hermann, Petr; Kotek, Jan

    2015-03-16

    Two macrocyclic ligands based on cyclam with trans-disposed N-methyl and N-(4-aminobenzyl) substituents as well as two methylphosphinic (H2L1) or methylphosphonic (H4L2) acid pendant arms were synthesised and investigated in solution. The ligands form stable complexes with transition metal ions. Both ligands show high thermodynamic selectivity for divalent copper over nickel(II) and zinc(II)-K(CuL) is larger than K(Ni/ZnL) by about seven orders of magnitude. Complexation is significantly faster for the phosphonate ligand H4L2, probably due to the stronger coordination ability of the more basic phosphonate groups, which efficiently bind the metal ion in an "out-of-cage" complex and thus accelerate its "in-cage" binding. The rate of Cu(II) complexation by the phosphinate ligand H2L1 is comparable to that of cyclam itself and its derivatives with non-coordinating substituents. Acid-assisted decomplexation of the copper(II) complexes is relatively fast (τ1/2 = 44 and 42 s in 1 M aq. HClO4 at 25 °C for H2L1 and H4L2, respectively). This combination of properties is convenient for selective copper removal/purification. Thus, the title ligands were employed in the preparation of ion-selective resins for radiocopper(II) separation. Glycidyl methacrylate copolymer beads were modified with the ligands through a diazotisation reaction. The separation ability of the modified polymers was tested with cold copper(II) and non-carrier-added (64)Cu in the presence of a large excess of both nickel(II) and zinc(II). The experiments exhibited high overall separation efficiency leading to 60-70% recovery of radiocopper with high selectivity over the other metal ions, which were originally present in 900-fold molar excess. The results showed that chelating resins with properly tuned selectivity of their complexing moieties can be employed for radiocopper separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. An optics-based variable-temperature assay system for characterizing thermodynamics of biomolecular reactions on solid support

    Energy Technology Data Exchange (ETDEWEB)

    Fei, Yiyan; Landry, James P.; Zhu, X. D., E-mail: xdzhu@physics.ucdavis.edu [Department of Physics, University of California, One Shields Avenue, Davis, California 95616 (United States); Li, Yanhong; Yu, Hai; Lau, Kam; Huang, Shengshu; Chokhawala, Harshal A.; Chen, Xi [Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616 (United States)

    2013-11-15

    A biological state is equilibrium of multiple concurrent biomolecular reactions. The relative importance of these reactions depends on physiological temperature typically between 10 °C and 50 °C. Experimentally the temperature dependence of binding reaction constants reveals thermodynamics and thus details of these biomolecular processes. We developed a variable-temperature opto-fluidic system for real-time measurement of multiple (400–10 000) biomolecular binding reactions on solid supports from 10 °C to 60 °C within ±0.1 °C. We illustrate the performance of this system with investigation of binding reactions of plant lectins (carbohydrate-binding proteins) with 24 synthetic glycans (i.e., carbohydrates). We found that the lectin-glycan reactions in general can be enthalpy-driven, entropy-driven, or both, and water molecules play critical roles in the thermodynamics of these reactions.

  3. Chemically-dissected Rotation Curves of the Galactic Bulge from Hubble Space Telescope Proper Motions on the Main Sequence

    Science.gov (United States)

    Clarkson, William I.; Calamida, Annalisa; Sahu, Kailash C.; Gennaro, Mario; Brown, Thomas M.; Avila, Roberto J.; Rich, R. Michael; Debattista, Victor P.

    2018-01-01

    We report results from a pilot study using archival Hubble Space Telescope imaging observations in seven filters over a multi-year time-baseline to probe the co-dependence of chemical abundance and kinematics, using proper motion-based rotation curves selected on relative metallicity. With spectroscopic studies suggesting the metallicity distribution of the Bulge may be bimodal, we follow a data-driven approach to classify stars as belonging to metal-rich or metal-poor ends of the observed relative photometric metallicity distribution, with classification implemented using standard unsupervised learning techniques. We detect clear differences in both slope and amplitude of the proper motion-based rotation curve as traced by the more “metal-rich” and “metal-poor” samples. The sense of the discrepancy is qualitatively in agreement both with recent observational and theoretical indications; the “metal-poor” sample does indeed show a weaker rotation signature.This is the first study to dissect the proper motion rotation curve of the Bulge by chemical abundance using main-sequence targets, which are orders of magnitude more common on the sky than bright giants. These techniques thus offer a pencil-beam complement to wide-field studies that use more traditional tracer populations.

  4. Spectroscopic classification of X-ray sources in the Galactic Bulge Survey

    Science.gov (United States)

    Wevers, T.; Torres, M. A. P.; Jonker, P. G.; Nelemans, G.; Heinke, C.; Mata Sánchez, D.; Johnson, C. B.; Gazer, R.; Steeghs, D. T. H.; Maccarone, T. J.; Hynes, R. I.; Casares, J.; Udalski, A.; Wetuski, J.; Britt, C. T.; Kostrzewa-Rutkowska, Z.; Wyrzykowski, Ł.

    2017-10-01

    We present the classification of 26 optical counterparts to X-ray sources discovered in the Galactic Bulge Survey. We use (time-resolved) photometric and spectroscopic observations to classify the X-ray sources based on their multiwavelength properties. We find a variety of source classes, spanning different phases of stellar/binary evolution. We classify CX21 as a quiescent cataclysmic variable (CV) below the period gap, and CX118 as a high accretion rate (nova-like) CV. CXB12 displays excess UV emission, and could contain a compact object with a giant star companion, making it a candidate symbiotic binary or quiescent low-mass X-ray binary (although other scenarios cannot be ruled out). CXB34 is a magnetic CV (polar) that shows photometric evidence for a change in accretion state. The magnetic classification is based on the detection of X-ray pulsations with a period of 81 ± 2 min. CXB42 is identified as a young stellar object, namely a weak-lined T Tauri star exhibiting (to date unexplained) UX Ori-like photometric variability. The optical spectrum of CXB43 contains two (resolved) unidentified double-peaked emission lines. No known scenario, such as an active galactic nucleus or symbiotic binary, can easily explain its characteristics. We additionally classify 20 objects as likely active stars based on optical spectroscopy, their X-ray to optical flux ratios and photometric variability. In four cases we identify the sources as binary stars.

  5. Thermodynamic Based Framework for Determining Sustainable Electric Infrastructures as well as Modeling of Decoherence in Quantum Composite Systems

    OpenAIRE

    Cano-Andrade, Sergio

    2014-01-01

    In this dissertation, applications of thermodynamics at the macroscopic and quantum levels of description are developed. Within the macroscopic level, an upper-level Sustainability Assessment Framework (SAF) is proposed for evaluating the sustainable and resilient synthesis/design and operation of sets of small renewable and non-renewable energy production technologies coupled to power production transmission and distribution networks via microgrids. The upper-level SAF is developed in accord...

  6. Thermodynamics in Einstein's thought

    International Nuclear Information System (INIS)

    Klein, M.J.

    1983-01-01

    The role of the thermodynamical approach in the Einstein's scientific work is analyzed. The Einstein's development of a notion about statistical fluctuations of thermodynamical systems that leads him to discovery of corpuscular-wave dualism is retraced

  7. Chemical thermodynamic representation of

    International Nuclear Information System (INIS)

    Lindemer, T.B.; Besmann, T.M.

    1984-01-01

    The entire data base for the dependence of the nonstoichiometry, x, on temperature and chemical potential of oxygen (oxygen potential) was retrieved from the literature and represented. This data base was interpreted by least-squares analysis using equations derived from the classical thermodynamic theory for the solid solution of a solute in a solvent. For hyperstoichiometric oxide at oxygen potentials more positive than -266700 + 16.5T kJ/mol, the data were best represented by a [UO 2 ]-[U 3 O 7 ] solution. For O/U ratios above 2 and oxygen potentials below this boundary, a [UO 2 ]-[U 2 O 4 . 5 ] solution represented the data. The data were represented by a [UO 2 ]-[U 1 / 3 ] solution. The resulting equations represent the experimental ln(PO 2 ) - ln(x) behavior and can be used in thermodynamic calculations to predict phase boundary compositions consistent with the literature. Collectively, the present analysis permits a mathematical representation of the behavior of the total data base

  8. An Overview of a Continuum Mechanic Approach to a Thermodynamic Model of Failure

    National Research Council Canada - National Science Library

    Palazotto, A

    1998-01-01

    .... An overview of the thermodynamic definitions, concepts, and principles will be presented. This overview of the thermodynamics is necessary to provided the background needed to understand the damage model, which is based on thermodynamic principles...

  9. Complexation of Oxovanadium(IV) and Dioxouranium(VI) with Synthesized 1,2-(Diimino-4′-antipyrinyl)-1,2-diphenylethane Schiff Base: A Thermodynamic, Kinetic, and Bioactivity Investigation

    OpenAIRE

    Shabnum Bashir; Syed Raashid Maqsood; Ghulam Mustafa Peerzada; Badruddin Khan; Masood Ahmad Rizvi

    2014-01-01

    We report the comparative synthetic methodologies and characterization of a tetradentate Schiff base ligand 1,2-(diimino-4′-antipyrinyl)-1,2-diphenylethane (DE). The target synthesis of oxovanadium(IV) and dioxouranium(VI) complexes (vanadyl and uranyl) with the (DE) ligand was also attempted to envisage the effect of metal ion steric factor on complexation process through solution phase thermodynamic and kinetic studies. The thermodynamic stabilities of synthesized vanadyl and uranyl (DE) co...

  10. The influence of changes in cervical lordosis on bulging disk and spinal stenosis: functional MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Joon; Eun, Choong Ki [Pusan Paik Hospital, Inje Univ. College of Medicine, Pusan (Korea, Republic of)

    2001-05-01

    To assess the effect of lordotic curve change of the cervical spine on disk bulging and spinal stenosis by means of functional cervical MR imaging at the flexion and extension position. Using a 1.5T imager, kinematic MR examinations of 25 patients with degenerative spondylosis (average age, 41 years) were performed at the neutral, flexed and extended position of the cervical spine. Sagittal T2-weighted turbo spin-echo images were obtained during each of the three phases. Lordotic angle, bulging thickness of the disk, AP diameter of the spinal canal, and distance between the disk and spinal cord were measured on the workstation at each disk level. After qualitative independent observation of disk bulging, one of four grades(0, normal; 1, mild; 2, moderate; 3, marked) was assigned at each phase, and after further comparative observation, one of five scores (-2, prominent decrease; -1, mild decrease; 0, no change; 1, notable increase; 2 prominent increase) was also assigned. In addition, bulging thickness of the disk was measured and compared at the neutral, flexed, and extended positions. Average angles of the cervical spine were 160.5{+-}5.9 deg (neutral position, lordotic angle); 185.4{+-}8.5 deg (flexion, kyphotic angle); and 143.7{+-}6.7 deg (extension, lordotic angle). Average grades of disk bulging were 0.55 at the neutral position. 0.16 at flexion, and 0.7 at extension. Comparative observation showed that average scores of disk bulging were -0.39 at flexion and 0.31 at extension. The bulging thickness of the disk decreased by 24.2% at flexion and increased by 30.3% at extension, while the diameter of the spinal canal increased by 4.5% at flexion and decreased by 3.6% at extension. The distance from the posterior margin of the disk to the anterior margin of the spinal cord decreased at both flexion(6.6%) and extension(19.1%). Functional MRI showed that compared with the neutral position, disk bulging and spinal stenosis are less prominent at flexion and

  11. Extremely metal-poor stars from the cosmic dawn in the bulge of the Milky Way.

    Science.gov (United States)

    Howes, L M; Casey, A R; Asplund, M; Keller, S C; Yong, D; Nataf, D M; Poleski, R; Lind, K; Kobayashi, C; Owen, C I; Ness, M; Bessell, M S; Da Costa, G S; Schmidt, B P; Tisserand, P; Udalski, A; Szymański, M K; Soszyński, I; Pietrzyński, G; Ulaczyk, K; Wyrzykowski, Ł; Pietrukowicz, P; Skowron, J; Kozłowski, S; Mróz, P

    2015-11-26

    The first stars are predicted to have formed within 200 million years after the Big Bang, initiating the cosmic dawn. A true first star has not yet been discovered, although stars with tiny amounts of elements heavier than helium ('metals') have been found in the outer regions ('halo') of the Milky Way. The first stars and their immediate successors should, however, preferentially be found today in the central regions ('bulges') of galaxies, because they formed in the largest over-densities that grew gravitationally with time. The Milky Way bulge underwent a rapid chemical enrichment during the first 1-2 billion years, leading to a dearth of early, metal-poor stars. Here we report observations of extremely metal-poor stars in the Milky Way bulge, including one star with an iron abundance about 10,000 times lower than the solar value without noticeable carbon enhancement. We confirm that most of the metal-poor bulge stars are on tight orbits around the Galactic Centre, rather than being halo stars passing through the bulge, as expected for stars formed at redshifts greater than 15. Their chemical compositions are in general similar to typical halo stars of the same metallicity although intriguing differences exist, including lower abundances of carbon.

  12. Introduction to applied thermodynamics

    CERN Document Server

    Helsdon, R M; Walker, G E

    1965-01-01

    Introduction to Applied Thermodynamics is an introductory text on applied thermodynamics and covers topics ranging from energy and temperature to reversibility and entropy, the first and second laws of thermodynamics, and the properties of ideal gases. Standard air cycles and the thermodynamic properties of pure substances are also discussed, together with gas compressors, combustion, and psychrometry. This volume is comprised of 16 chapters and begins with an overview of the concept of energy as well as the macroscopic and molecular approaches to thermodynamics. The following chapters focus o

  13. A Vector Representation for Thermodynamic Relationships

    Science.gov (United States)

    Pogliani, Lionello

    2006-01-01

    The existing vector formalism method for thermodynamic relationship maintains tractability and uses accessible mathematics, which can be seen as a diverting and entertaining step into the mathematical formalism of thermodynamics and as an elementary application of matrix algebra. The method is based on ideas and operations apt to improve the…

  14. Quantum quenches in the thermodynamic limit.

    Science.gov (United States)

    Rigol, M

    2014-05-02

    We introduce a linked-cluster based computational approach that allows one to study quantum quenches in lattice systems in the thermodynamic limit. This approach is used to study quenches in one-dimensional lattices. We provide evidence that, in the thermodynamic limit, thermalization occurs in the nonintegrable regime but fails at integrability. A phase transitionlike behavior separates the two regimes.

  15. Interlayer growth kinetics of a binary solid-solution based on the thermodynamic extremal principle: Application to the formation of spinel at periclase-corundum contacts

    Czech Academy of Sciences Publication Activity Database

    Abart, R.; Svoboda, Jiří; Jeřábek, P.; Povoden-Karadeniz, E.; Habler, G.

    2016-01-01

    Roč. 316, č. 4 (2016), s. 309-328 ISSN 0002-9599 Institutional support: RVO:68081723 Keywords : reactive dffusion * interface migration * thermodynamic modeling * spinel Subject RIV: BJ - Thermodynamics Impact factor: 4.099, year: 2016

  16. The GIRAFFE Inner Bulge Survey (GIBS). II. Metallicity distributions and alpha element abundances at fixed Galactic latitude

    Science.gov (United States)

    Gonzalez, O. A.; Zoccali, M.; Vasquez, S.; Hill, V.; Rejkuba, M.; Valenti, E.; Rojas-Arriagada, A.; Renzini, A.; Babusiaux, C.; Minniti, D.; Brown, T. M.

    2015-12-01

    Aims: We investigate metallicity and α-element abundance gradients along a Galactic longitude strip, at latitude b ~ -4°, with the aim of providing observational constraints for the structure and origin of the Milky Way bulge. Methods: High-resolution (R ~ 22 500) spectra for 400 K giants, in four fields within -4.8° ≲ b ≲ -3.4° and -10° ≲ l ≲ +10°, were obtained within the GIRAFFE Inner Bulge Survey (GIBS) project. To this sample we added another ~400 stars in Baade's Window at (l,b) = (1°,-4°), observed with the identical instrumental configuration: FLAMES GIRAFFE in Medusa mode with HR13 setup. All target stars lie within the red clump of the bulge colour-magnitude diagram, thus minimising contamination from the disc or halo stars. The spectroscopic stellar surface parameters were derived with an automatic method based on the GALA code, while the [Ca/Fe] and [Mg/Fe] abundances as a function of [Fe/H] were derived through a comparison with the synthetic spectra using MOOG. We constructed the metallicity distributions for the entire sample, and for each field individually, in order to investigate the presence of gradients or field-to-field variations in the shape of the distributions. Results: The metallicity distributions in the five fields are consistent with being drawn from a single parent population, indicating the absence of a gradient along the major axis of the Galactic bar. The global metallicity distribution is nicely fitted by two Gaussians. The metal-poor component is rather broad, with a mean at ⟨ [Fe/H] ⟩ = -0.31 dex and σ = 0.31 dex. The metal-rich component is narrower, with mean ⟨ [Fe/H] ⟩ = + 0.26 and σ = 0.2 dex. The [Mg/Fe] ratio follows a tight trend with [Fe/H], with enhancement with respect to solar in the metal-poor regime similar to the value observed for giant stars in the local thick disc. [Ca/Fe] abundances follow a similar trend, but with a considerably larger scatter than [Mg/Fe]. A decrease in [Mg/Fe] is

  17. Rational extended thermodynamics

    CERN Document Server

    Müller, Ingo

    1998-01-01

    Ordinary thermodynamics provides reliable results when the thermodynamic fields are smooth, in the sense that there are no steep gradients and no rapid changes. In fluids and gases this is the domain of the equations of Navier-Stokes and Fourier. Extended thermodynamics becomes relevant for rapidly varying and strongly inhomogeneous processes. Thus the propagation of high­ frequency waves, and the shape of shock waves, and the regression of small-scale fluctuation are governed by extended thermodynamics. The field equations of ordinary thermodynamics are parabolic while extended thermodynamics is governed by hyperbolic systems. The main ingredients of extended thermodynamics are • field equations of balance type, • constitutive quantities depending on the present local state and • entropy as a concave function of the state variables. This set of assumptions leads to first order quasi-linear symmetric hyperbolic systems of field equations; it guarantees the well-posedness of initial value problems and f...

  18. Linearization-based method for solving a multicomponent diffusion phase-field model with arbitrary solution thermodynamics

    Science.gov (United States)

    Welland, M. J.; Tenuta, E.; Prudil, A. A.

    2017-06-01

    This article describes a phase-field model for an isothermal multicomponent, multiphase system which avoids implicit interfacial energy contributions by starting from a grand potential formulation. A method is developed for incorporating arbitrary forms of the equilibrium thermodynamic potentials in all phases to determine an explicit relationship between chemical potentials and species concentrations. The model incorporates variable densities between adjacent phases, defect migration, and dependence of internal pressure on object dimensions ranging from the macro- to nanoscale. A demonstrative simulation of an overpressurized nanoscopic intragranular bubble in nuclear fuel migrating to a grain boundary under kinetically limited vacancy diffusion is shown.

  19. Thermodynamics of acid-base dissociation of several cathinones and 1-phenylethylamine, studied by an accurate capillary electrophoresis method free from the Joule heating impact.

    Science.gov (United States)

    Nowak, Paweł Mateusz; Woźniakiewicz, Michał; Mitoraj, Mariusz; Sagan, Filip; Kościelniak, Paweł

    2018-03-02

    Capillary electrophoresis is often used to the determination of the acid-base dissociation/deprotonation constant (pK a ), and the more advanced thermodynamic quantities describing this process (ΔH°, -TΔS°). Remarkably, it is commonly overlooked that due to insufficient dissipation of Joule heating the accuracy of parameters determined using a standard approach may be questionable. In this work we show an effective method allowing to enhance reliability of these parameters, and to estimate the magnitude of errors. It relies on finding a relationship between electrophoretic mobility and actual temperature, and performing pK a determination with the corrected mobility values. It has been employed to accurately examine the thermodynamics of acid-base dissociation of several amine compounds - known for their strong dependency of pK a on temperature: six cathinones (2-methylmethcathinone, 3-methylmethcathinone, 4-methylmethcathinone, α-pyrrolidinovalerophenone, methylenedioxypyrovalerone, and ephedrone); and structurally similar 1-phenylethylamine. The average pK a error caused by Joule heating noted at 25 °C was relatively small - 0.04-0.05 pH unit, however, a more significant inaccuracy was observed in the enthalpic and, in particular, entropic terms. An alternative correction method has also been proposed, simpler and faster, but not such effective in correcting ΔH°/-TΔS° terms. The corrected thermodynamic data have been interpreted with the aid of theoretical calculations, on a ground of the enthalpy-entropy relationships and the most probable structural effects accounting for them. Finally, we have demonstrated that the thermal dependencies of electrophoretic mobility, modelled during the correction procedure, may be directly used to find optimal temperature providing a maximal separation efficiency. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. THE EVOLUTION OF THE KINEMATICS OF NEBULAR SHELLS IN PLANETARY NEBULAE IN THE MILKY WAY BULGE

    International Nuclear Information System (INIS)

    Richer, Michael G.; Lopez, Jose Alberto; Garcia-Diaz, Maria Teresa; Clark, David M.; Pereyra, Margarita; Diaz-Mendez, Enrique

    2010-01-01

    We study the line widths in the [O III]λ5007 and Hα lines for two groups of planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the Observatorio Astronomico Nacional in the Sierra San Pedro Martir (OAN-SPM) using the Manchester Echelle Spectrograph. The first sample includes objects early in their evolution, having high Hβ luminosities, but [O III]λ5007/Hβ 0.5. These planetary nebulae represent evolutionary phases preceding and following those of the objects studied by Richer et al. in 2008. Our sample of planetary nebulae with weak [O III]λ5007 has a line width distribution similar to that of the expansion velocities of the envelopes of asymptotic giant branch stars and shifted to systematically lower values as compared to the less evolved objects studied by Richer et al. The sample with strong He II λ4686 has a line width distribution indistinguishable from that of the more evolved objects from Richer et al., but a distribution in angular size that is systematically larger and so they are clearly more evolved. These data and those of Richer et al. form a homogeneous sample from a single Galactic population of planetary nebulae, from the earliest evolutionary stages until the cessation of nuclear burning in the central star. They confirm the long-standing predictions of hydrodynamical models of planetary nebulae, where the kinematics of the nebular shell are driven by the evolution of the central star.

  1. Thermodynamics of the hot BIon

    DEFF Research Database (Denmark)

    Grignani, Gianluca; Harmark, Troels; Marini, Andrea

    2011-01-01

    We investigate the thermodynamics of the recently obtained nite temperature BIon solution of arXiv:1012.1494, focusing on two aspects. The first concerns comparison of the free energy of the three available phases for the finite temperature brane-antibrane wormhole configuration. Based on this we...... is the possibility of constructing a finite temperature generalization of the infinite spike configuration of the extremal BIon. To this end we identify a correspondence point at the end of the throat where the thermodynamics of the D3-F1 blackfold configuration can be matched to that of k non-extremal black...

  2. Teaching Thermodynamics of Ideal Solutions: An Entropy-Based Approach to Help Students Better Understand and Appreciate the Subtleties of Solution Models

    Science.gov (United States)

    Tomba, J. Pablo

    2015-01-01

    The thermodynamic formalism of ideal solutions is developed in most of the textbooks postulating a form for the chemical potential of a generic component, which is adapted from the thermodynamics of ideal gas mixtures. From this basis, the rest of useful thermodynamic properties can be derived straightforwardly without further hypothesis. Although…

  3. The Globular Clusters of the Galactic Bulge: Results from Multiwavelength Follow-up Imaging

    Science.gov (United States)

    Cohen, Roger; Geisler, Doug; Mauro, Francesco; Alonso Garcia, Javier; Hempel, Maren; Sarajedini, Ata

    2018-01-01

    The Galactic globular clusters (GGCs) located towards the bulge of the Milky Way suffer from severe total and differential extinction and high field star densities. They have therefore been systematically excluded from deep, large-scale homogenous GGC surveys, and will present a challenge for Gaia. Meanwhile, existing observations of bulge GGCs have revealed tantalizing hints that they hold clues to Galactic formation and evolution not found elsewhere. Therefore, in order to better characterize these poorly studied stellar systems and place them in the context of their optically well-studied counterparts, we have undertaken imaging programs at optical and near-infrared wavelengths. We describe these programs and present a variety of results, including self-consistent measurement of bulge GGC ages and structural parameters. The limitations imposed by spatially variable extinction and extinction law are highlighted, along with the complimentary nature of forthcoming facilities, allowing us to finally complete our picture of the Milky Way GGC system.

  4. Tracing the Chemical Evolution of Metal-rich Galactic Bulge Globular Clusters

    Science.gov (United States)

    Munoz Gonzalez, Cesar; Saviane, Ivo; Geisler, Doug; Villanova, Sandro

    2018-01-01

    We present in this poster the metallicity characterization of the four metal rich Bulge Galactic Gobular Clusters, which have controversial metallicities. We analyzed our high-resolution spectra (using UVES-580nm and GIRAFFE-HR13 setups) for a large sample of RGB/AGB targets in each cluster in order to measure their metallicity and prove or discard the iron spread hypothesis. We have also characterized chemically stars with potentially different iron content by measuring light (O, Na, Mg, Al), alpha (Si, Ca, Ti), iron–peak (V, Cr, Ni, Mn) and s and r process (Y, Zr, Ba, Eu) elements. We have identified possible channels responsible for the chemical heterogeneity of the cluster populations, like AGB or massive fast-rotating stars contamination, or SN explosion. Also, we have analyzed the origin and evolution of these bulge GCs and their connection with the bulge itself.

  5. Thermodynamics of a Compressible Maier-Saupe Model Based on the Self-Consistent Field Theory of Wormlike Polymer

    Directory of Open Access Journals (Sweden)

    Ying Jiang

    2017-02-01

    Full Text Available This paper presents a theoretical formalism for describing systems of semiflexible polymers, which can have density variations due to finite compressibility and exhibit an isotropic-nematic transition. The molecular architecture of the semiflexible polymers is described by a continuum wormlike-chain model. The non-bonded interactions are described through a functional of two collective variables, the local density and local segmental orientation tensor. In particular, the functional depends quadratically on local density-variations and includes a Maier–Saupe-type term to deal with the orientational ordering. The specified density-dependence stems from a free energy expansion, where the free energy of an isotropic and homogeneous homopolymer melt at some fixed density serves as a reference state. Using this framework, a self-consistent field theory is developed, which produces a Helmholtz free energy that can be used for the calculation of the thermodynamics of the system. The thermodynamic properties are analysed as functions of the compressibility of the model, for values of the compressibility realizable in mesoscopic simulations with soft interactions and in actual polymeric materials.

  6. Thermodynamics of geothermal fluids

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, P.S.Z.

    1981-03-01

    A model to predict the thermodynamic properties of geothermal brines, based on a minimum amount of experimental data on a few key systems, is tested. Volumetric properties of aqueous sodium chloride, taken from the literature, are represented by a parametric equation over the range 0 to 300{sup 0}C and 1 bar to 1 kbar. Density measurements at 20 bar needed to complete the volumetric description also are presented. The pressure dependence of activity and thermal properties, derived from the volumetric equation, can be used to complete an equation of state for sodium chloride solutions. A flow calorimeter, used to obtain heat capacity data at high temperatures and pressures, is described. Heat capacity measurements, from 30 to 200{sup 0}C and 1 bar to 200 bar, are used to derive values for the activity coefficient and other thermodynamic properties of sodium sulfate solutions as a function of temperature. Literature data on the solubility of gypsum in mixed electrolyte solutions have been used to evaluate model parameters for calculating gypsum solubility in seawater and natural brines. Predictions of strontium and barium sulfate solubility in seawater also are given.

  7. TWO-COMPONENT GALACTIC BULGE PROBED WITH RENEWED GALACTIC CHEMICAL EVOLUTION MODEL

    International Nuclear Information System (INIS)

    Tsujimoto, Takuji; Bekki, Kenji

    2012-01-01

    Results of recent observations of the Galactic bulge demand that we discard a simple picture of its formation, suggesting the presence of two stellar populations represented by two peaks of stellar metallicity distribution (MDF) in the bulge. To assess this issue, we construct Galactic chemical evolution models that have been updated in two respects: first, the delay time distribution of Type Ia supernovae (SNe Ia) recently revealed by extensive SN Ia surveys is incorporated into the models. Second, the nucleosynthesis clock, the s-processing in asymptotic giant branch stars, is carefully considered in this study. This novel model first shows that the Galaxy feature tagged by the key elements, Mg, Fe, and Ba, for the bulge as well as thin and thick disks is compatible with a short-delay SN Ia. We present a successful modeling of a two-component bulge including the MDF and the evolutions of [Mg/Fe] and [Ba/Mg], and reveal its origin as follows. A metal-poor component (([Fe/H]) ∼ –0.5) is formed with a relatively short timescale of ∼1 Gyr. These properties are identical to the thick disk's characteristics in the solar vicinity. Subsequently from its remaining gas mixed with a gas flow from the disk outside the bulge, a metal-rich component (([Fe/H]) ∼ +0.3) is formed with a longer timescale (∼4 Gyr) together with a top-heavy initial mass function that might be identified with the thin disk component within the bulge.

  8. The imprints of bars on the vertical stellar population gradients of galactic bulges

    Science.gov (United States)

    Molaeinezhad, A.; Falcón-Barroso, J.; Martínez-Valpuesta, I.; Khosroshahi, H. G.; Vazdekis, A.; La Barbera, F.; Peletier, R. F.; Balcells, M.

    2017-05-01

    This is the second paper of a series aimed to study the stellar kinematics and population properties of bulges in highly inclined barred galaxies. In this work, we carry out a detailed analysis of the stellar age, metallicity and [Mg/Fe] of 28 highly inclined (I > 65°) disc galaxies, from S0 to S(B)c, observed with the SAURON integral-field spectrograph. The sample is divided into two clean samples of barred and unbarred galaxies, on the basis of the correlation between the stellar velocity and h3 profiles, as well as the level of cylindrical rotation within the bulge region. We find that while the mean stellar age, metallicity and [Mg/Fe] in the bulges of barred and unbarred galaxies are not statistically distinct, the [Mg/Fe] gradients along the minor axis (away from the disc) of barred galaxies are significantly different than those without bars. For barred galaxies, stars that are vertically further away from the mid-plane are in general more [Mg/Fe]-enhanced and thus the vertical gradients in [Mg/Fe] for barred galaxies are mostly positive, while for unbarred bulges the [Mg/Fe] profiles are typically negative or flat. This result, together with the old populations observed in the barred sample, indicates that bars are long-lasting structures, and therefore are not easily destroyed. The marked [Mg/Fe] differences with the bulges of unbarred galaxies indicate that different formation/evolution scenarios are required to explain their build-up, and emphasizes the role of bars in redistributing stellar material in the bulge-dominated regions.

  9. Most pseudo-bulges can be formed at later stages of major mergers

    Science.gov (United States)

    Sauvaget, T.; Hammer, F.; Puech, M.; Yang, Y. B.; Flores, H.; Rodrigues, M.

    2018-01-01

    Most giant spiral galaxies have pseudo or disc-like bulges that are considered to be the result of purely secular processes. This may challenge the hierarchical scenario predicting about one major merger per massive galaxy (>3 × 1010 M⊙) since the last ∼9 billion years. Here, we verify whether or not the association between pseudo-bulges and secular processes is irrevocable. Using GADGET2 N-body/SPH simulations, we have conducted a systematic study of remnants of major mergers for which progenitors have been selected (1) to follow the gas richness-look back time relationship, and (2) with a representative distribution of orbits and spins in a cosmological frame. Analysing the surface mass density profile of both nearby galaxies and merger remnants with two components, we find that most of them show pseudo-bulges or bar dominated centres. Even if some orbits lead to classical bulges just after the fusion, the contamination by the additional gas that gradually accumulates to the centre and forming stars later on, leads to remnants apparently dominated by pseudo-bulges. We also found that simple smoothed particle hydrodynamics (SPH) simulations should be sufficient to form realistic spiral galaxies as remnants of ancient gas-rich mergers without the need for specifically tuned feedback conditions. We then conclude that pseudo-bulges and bars in spiral galaxies are natural consequences of major mergers when they are realized in a cosmological context, i.e. with gas-rich progenitors as expected when selected in the distant Universe.

  10. The peculiar Na-O anticorrelation of the bulge globular cluster NGC 6440

    Science.gov (United States)

    Muñoz, C.; Villanova, S.; Geisler, D.; Saviane, I.; Dias, B.; Cohen, R. E.; Mauro, F.

    2017-08-01

    Context. Galactic globular clusters (GCs) are essential tools for understanding the earliest epoch of the Milky Way, since they are among the oldest objects in the Universe and can be used to trace its formation and evolution. Current studies using high-resolution spectroscopy for many stars in each of a large sample of GCs allow us to develop a detailed observational picture of their formation and their relation with the Galaxy. However, it is necessary to complete this picture by including GCs that belong to all major Galactic components, including the bulge. Aims: Our aim is to perform a detailed chemical analysis of the bulge GC NGC 6440 in order to determine if this object has multiple populations (MPs) and investigate its relation with the bulge of the Milky Way and with the other Galactic GCs, especially those associated with the bulge, which are largely poorly studied. Methods: We determined the stellar parameters and the chemical abundances of light elements (Na, Al), iron-peak elements (Fe, Sc, Mn, Co, Ni), α-elements (O, Mg, Si, Ca, Ti) and heavy elements (Ba, Eu) in seven red giant members of NGC 6440 using high-resolution spectroscopy from FLAMES-UVES. Results: We found a mean iron content of [Fe/H] =-0.50 ± 0.03 dex in agreement with other studies. We found no internal iron spread. On the other hand, Na and Al show a significant intrinsic spread, but the cluster has no significant O-Na anticorrelation nor does it exhibit a Mg-Al anticorrelation. The α-elements show good agreement with the bulge field star trend, although they are at the high alpha end and are also higher than those of other GCs of comparable metallicity. The heavy elements are dominated by the r-process, indicating a strong contribution by SNeII. The chemical analysis suggests an origin similar to that of the bulge field stars.

  11. A simple conductometric method for trace level determination of brilliant green in water based on β-cyclodextrin and silver nitrate and determination of their thermodynamic parameters

    Directory of Open Access Journals (Sweden)

    Roya Mohammad Zadeh Kakhki

    2014-12-01

    Full Text Available A gravimetric and complexometric titration method based on conductometric technique is presented for the quantitative determination of brilliant green (BG in water. The equilibrium constants and the thermodynamic parameters for the complex formation of β-cyclodextrin (β-CD with brilliant green (BG and precipitation of silver nitrate with BG have been determined by conductivity measurements in water. The results suggest that stable 1:1 complex is formed between BG and β-cyclodextrin and the thermodynamic parameters (ΔHc°,ΔSc° for this complexation reaction have been determined from temperature dependence of the stability constant using the van’t Hoff plots. Based on the obtained results, the conductometric method for the determination of BG in the presence of β-CD at 25 °C was developed in the range of 10−8–10−3 molL−1 and with AgNO3 is 10−3–10−5 molL−1.

  12. Images in the rocket ultraviolet: The stellar population in the central bulge of M31

    International Nuclear Information System (INIS)

    Bohlin, R.C.; Cornett, R.H.; Hill, J.K.; Hill, R.S.; O'Connell, R.W.; Stecher, T.P.

    1985-01-01

    We discuss imagery of bulge of the M31 obtained with a rocket-borne telescope in two broad bands centered at 1460 A and 2380 A. The UV spatial profiles over a region approx.200'' wide are identical with those at visible wavelengths. The absence of detectable point sources indicates that main-sequence stars hotter than BO V are not present in the bulge. We suggest that the far-UV flux in old stellar populations originates in post-AGB stars. The UV flux from such stars is extremely sensitive to age and the physics of their previous mass loss

  13. An introduction to equilibrium thermodynamics

    CERN Document Server

    Morrill, Bernard; Hartnett, James P; Hughes, William F

    1973-01-01

    An Introduction to Equilibrium Thermodynamics discusses classical thermodynamics and irreversible thermodynamics. It introduces the laws of thermodynamics and the connection between statistical concepts and observable macroscopic properties of a thermodynamic system. Chapter 1 discusses the first law of thermodynamics while Chapters 2 through 4 deal with statistical concepts. The succeeding chapters describe the link between entropy and the reversible heat process concept of entropy; the second law of thermodynamics; Legendre transformations and Jacobian algebra. Finally, Chapter 10 provides a

  14. Thermodynamics for scientists and engineers

    International Nuclear Information System (INIS)

    Lim, Gyeong Hui

    2011-02-01

    This book deals with thermodynamics for scientists and engineers. It consists of 11 chapters, which are concept and background of thermodynamics, the first law of thermodynamics, the second law of thermodynamics and entropy, mathematics related thermodynamics, properties of thermodynamics on pure material, equilibrium, stability of thermodynamics, the basic of compound, phase equilibrium of compound, excess gibbs energy model of compound and activity coefficient model and chemical equilibrium. It has four appendixes on properties of pure materials and thermal mass.

  15. Riemannian geometry in thermodynamic fluctuation theory

    International Nuclear Information System (INIS)

    Ruppeiner, G.

    1995-01-01

    Although thermodynamic fluctuation theory originated from statistical mechanics, it may be put on a completely thermodynamic basis, in no essential need of any microscopic foundation. This review views the theory from the macroscopic perspective, emphasizing, in particular, notions of covariance and consistency, expressed naturally using the language of Riemannian geometry. Coupled with these concepts is an extension of the basic structure of thermodynamic fluctuation theory beyond the classical one of a subsystem in contact with an infinite uniform reservoir. Used here is a hierarchy of concentric subsystems, each of which samples only the thermodynamic state of the subsystem immediately larger than it. The result is a covariant thermodynamic fluctuation theory which is plausible beyond the standard second-order entropy expansion. It includes the conservation laws and is mathematically consistent when applied to fluctuations inside subsystems. Tests on known models show improvements. Perhaps most significantly, the covariant theory offers a qualitatively new tool for the study of fluctuation phenomena: the Riemannian thermodynamic curvature. The thermodynamic curvature gives, for any given thermodynamic state, a lower bound for the length scale where the classical thermodynamic fluctuation theory based on a uniform environment could conceivably hold. Straightforward computation near the critical point reveals that the curvature equals the correlation volume, a physically appealing finding. The combination of the interpretation of curvature with a well-known proportionality between the free energy and the inverse of the correlation volume yields a purely thermodynamic theory of the critical point. The scaled equation of state follows from the values of the critical exponents. The thermodynamic Riemannian metric may be put into the broader context of information theory

  16. Thermodynamics of Bioreactions.

    Science.gov (United States)

    Held, Christoph; Sadowski, Gabriele

    2016-06-07

    Thermodynamic principles have been applied to enzyme-catalyzed reactions since the beginning of the 1930s in an attempt to understand metabolic pathways. Currently, thermodynamics is also applied to the design and analysis of biotechnological processes. The key thermodynamic quantity is the Gibbs energy of reaction, which must be negative for a reaction to occur spontaneously. However, the application of thermodynamic feasibility studies sometimes yields positive Gibbs energies of reaction even for reactions that are known to occur spontaneously, such as glycolysis. This article reviews the application of thermodynamics in enzyme-catalyzed reactions. It summarizes the basic thermodynamic relationships used for describing the Gibbs energy of reaction and also refers to the nonuniform application of these relationships in the literature. The review summarizes state-of-the-art approaches that describe the influence of temperature, pH, electrolytes, solvents, and concentrations of reacting agents on the Gibbs energy of reaction and, therefore, on the feasibility and yield of biological reactions.

  17. Design of desalination system based on multistage flash distillation (MSF) method : MSF desalination process and thermodynamics aspect

    International Nuclear Information System (INIS)

    Sunaryo, G.R.; Sumijanto; Latifah, S.N.

    1999-01-01

    During the development of making fresh water for supplying the potable water in Jakarta and eastern Indonesia, Indonesia Atomic Energy Agency (BATAN) has been developing the application of small power reactor for dual purposes,electricity and fresh water producing. One of the most popular method, because of the cheapest maintenance, is the Multi Stage Flash Distillation (MSF) which us study on designing the miniscale of MDF, the process fundamental aspects are the scale formation, degassing dissolved gas and diminishing foam, and from the thermodynamic aspect it is known that the total amount of heat required for MSF desalination is equal to free energy differences between water in solution and pure water times the ratio of total boiling temperature and the boiling temperature elevation with boiling temperature, where the range value is 35-40 kj/kg. Since the complex aspect of irreversible the heat required become 7 times higher as 240∼280 kj/kg

  18. Friedel's salt profiles from thermogravimetric analysis and thermodynamic modelling of Portland cement-based mortars exposed to sodium chloride solution

    DEFF Research Database (Denmark)

    Shi, Zhenguo; Geiker, Mette Rica; Lothenbach, Barbara

    2017-01-01

    indicates that only a minor part of the chloride ions is bound in Friedel's in the studied Portland cement (P) and limestone blended (L) cement. The chloride binding capacity with respect to the formation of Friedel's salt by consumption of monocarbonate is reached for the P and L mortars, where only...... a fraction of about 20% of the amount of C3A is found to contribute to formation of Friedel's salt. Higher amounts of Friedel's salt are formed in the metakaolin containing mortars. However, the limited chloride ingress depths prevent quantification of the potential full chloride binding capacity of Friedel......Thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and thermodynamic modelling have been used to obtain Friedel's salt profiles for saturated mortar cylinders exposed to a 2.8 M NaCl solution. Comparison of the measured Friedel's salt profiles with the total chloride profiles...

  19. Effect of different sulfides on cadmium distribution during sludge combustion based on experimental and thermodynamic calculation approaches.

    Science.gov (United States)

    Liu, Jing-Yong; Fu, Jie-Wen; Sun, Shui-Yu; Ning, Xun-An; Wang, Yu-Jie; Chen, Tao; Luo, Guang-Qian; Xie, Wu-Ming; Yang, Zuo-Yi; Zhuo, Zhong-Xu

    2015-01-01

    The effects of sulfur compounds on the migration of a semi-volatile heavy metal (cadmium) during sludge incineration were investigated with two methods, i.e., experiments in a tubular furnace reactor and thermodynamic equilibrium calculations. The representative typical sludge with and without the addition of sulfur compounds was incinerated at 850 °C. The partitioning of Cd among the solid phase (bottom ash) and gas phase (fly ash and flue gas) was quantified. The results indicate that sulfur compounds in the elemental form and a reduced state could stabilize Cd in the form of CdS, aluminosilicate minerals, and polymetallic sulfides, whereas sulfur in the oxidized forms slightly increases Cd volatilization during incineration. For Cd solidification points, the inhibition effect on the volatilization of Cd is as follows: S > Na2SO4 > Na2S. Chemical equilibrium calculations indicate that sulfur binds with Cd and alters Cd speciation at low temperatures (sludge incineration.

  20. The pressure dependence of structural, electronic, mechanical, vibrational, and thermodynamic properties of palladium-based Heusler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Coban, Cansu [Balikesir Univ. (Turkey). Dept. of Physics

    2017-07-01

    The pressure dependent behaviour of the structural, electronic, mechanical, vibrational, and thermodynamic properties of Pd{sub 2}TiX (X=Ga, In) Heusler alloys was investigated by ab initio calculations. The lattice constant, the bulk modulus and its first pressure derivative, the electronic band structure and the density of states (DOS), mechanical properties such as elastic constants, anisotropy factor, Young's modulus, etc., the phonon dispersion curves and phonon DOS, entropy, heat capacity, and free energy were obtained under pressure. It was determined that the calculated lattice parameters are in good agreement with the literature, the elastic constants obey the stability criterion, and the phonon dispersion curves have no negative frequency which shows that the compounds are stable. The band structures at 0, 50, and 70 GPa showed valence instability at the L point which explains the superconductivity in Pd{sub 2}TiX (X=Ga, In).

  1. Methods of thermodynamics

    CERN Document Server

    Reiss, Howard

    1997-01-01

    Since there is no shortage of excellent general books on elementary thermodynamics, this book takes a different approach, focusing attention on the problem areas of understanding of concept and especially on the overwhelming but usually hidden role of ""constraints"" in thermodynamics, as well as on the lucid exposition of the significance, construction, and use (in the case of arbitrary systems) of the thermodynamic potential. It will be especially useful as an auxiliary text to be used along with any standard treatment.Unlike some texts, Methods of Thermodynamics does not use statistical m

  2. Thermodynamics of nuclear materials

    International Nuclear Information System (INIS)

    Rand, M.H.

    1975-01-01

    A report is presented of the Fourth International Symposium on Thermodynamics of Nuclear Materials held in Vienna, 21-25 October 1974. The technological theme of the Symposium was the application of thermodynamics to the understanding of the chemistry of irradiated nuclear fuels and to safety assessments for hypothetical accident conditions in reactors. The first four sessions were devoted to these topics and they were followed by four more sessions on the more basic thermodynamics, phase diagrams and the thermodynamic properties of a wide range of nuclear materials. Sixty-seven papers were presented

  3. Application of computational thermodynamics to the determination of thermophysical properties as a function of temperature for multicomponent Al-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Fabiana C. [Fluminense Federal University, Graduate Program in Metallurgical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Paresque, Mara C.C. [Fluminense Federal University, Graduate Program in Mechanical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Castro, José A. de [Fluminense Federal University, Graduate Program in Metallurgical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Jácome, Paulo A.D. [Fluminense Federal University, Graduate Program in Mechanical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil); Garcia, Amauri, E-mail: amaurig@fem.unicamp.br [University of Campinas – UNICAMP, Department of Manufacturing and Materials Engineering, 13083-860 Campinas, SP (Brazil); Ferreira, Ivaldo L. [Fluminense Federal University, Graduate Program in Mechanical Engineering, Av. dos Trabalhadores, 420-27255-125 Volta Redonda, RJ (Brazil)

    2015-11-10

    Highlights: • A model coupled to a computational thermodynamics software is proposed to compute thermophysical properties. • The model applies to multicomponent alloys and has been validated against experimental results. • Density and specific heat as a function of temperature are computed for Al–Si–Cu alloys. - Abstract: Despite the technological importance of Al–Si–Cu alloys in manufacturing processes involving heat transfer, such as welding, casting and heat treatment, thermophysical properties of this system of alloys are very scarce in the literature. In this paper, a model connected to a computational thermodynamics software is proposed permitting density and specific heats as a function of temperature and enthalpy of transformations to be numerically determined. The model is pre-validated against experimental density as a function of temperature for liquid and solid phases of A319 and 7075 alloys found in the literature and validated against experimental density values for the solid phase of an Al-6 wt%Cu-1 wt%Si alloy determined in the present study. In both cases the numerical predictions are in good agreement with the experimental results. Specific heat and temperatures and heats of transformation are also numerically determined for this ternary Al-based alloy.

  4. Application of Statistical Thermodynamics in Refrigeration

    International Nuclear Information System (INIS)

    Avsec, J.; Marcic, M.

    1999-01-01

    The paper presents the mathematical model for computing the thermodynamical properties in the liquid, gas and two-phase domain by means of statistical thermodynamics. The paper features all important components (translation, rotation, internal rotation, vibration, intermolecular potential energy and influence of electron and nuclei excitation). To calculate the thermodynamic properties of real gases, we have developed the cluster theory, which yields better results than the virial equation. In case of real liquids, the Johnson-Zollweg-Gubbins model based on the modified Benedict-Webb-Rubin (BWR) equation was applied. The Lennard-Jones intermolecular potential was used. The analytical results are compared with the thermodynamical data and models obtained from classical thermodynamics, and they show relatively good agreement. (author)

  5. Introduction to the thermodynamics of solids

    International Nuclear Information System (INIS)

    Ericksen, J.L.

    1992-01-01

    This book addresses issues of thermodynamics associated with solids from a unique point of view. Professor Ericksen provides a perspective of thermodynamics which is based in material science and solid mechanics, and attempts to apply basic thermodynamics to a wide range of phenomena. The book is not written as a text-book, as it does not contain example problems or exercises, is directed primarily at researchers in solids. The author states that much of the book is controversial, and that many of his treatments of thermodynamics are not traditional. The author's assessment is accurate on both counts. However, there are several reasons to believe that many of the issues raised in the book are not so much controversial, but rather simply not well described, either by the author or by thermodynamicists, in general. The primary references for much of the thermodynamics in the book are historic in nature, and certainly worthy of consideration, but only a few current references are provided

  6. Simulating metabolism with statistical thermodynamics.

    Science.gov (United States)

    Cannon, William R

    2014-01-01

    New methods are needed for large scale modeling of metabolism that predict metabolite levels and characterize the thermodynamics of individual reactions and pathways. Current approaches use either kinetic simulations, which are difficult to extend to large networks of reactions because of the need for rate constants, or flux-based methods, which have a large number of feasible solutions because they are unconstrained by the law of mass action. This report presents an alternative modeling approach based on statistical thermodynamics. The principles of this approach are demonstrated using a simple set of coupled reactions, and then the system is characterized with respect to the changes in energy, entropy, free energy, and entropy production. Finally, the physical and biochemical insights that this approach can provide for metabolism are demonstrated by application to the tricarboxylic acid (TCA) cycle of Escherichia coli. The reaction and pathway thermodynamics are evaluated and predictions are made regarding changes in concentration of TCA cycle intermediates due to 10- and 100-fold changes in the ratio of NAD+:NADH concentrations. Finally, the assumptions and caveats regarding the use of statistical thermodynamics to model non-equilibrium reactions are discussed.

  7. Thermodynamic and economic studies of two new high efficient power-cooling cogeneration systems based on Kalina and absorption refrigeration cycles

    International Nuclear Information System (INIS)

    Rashidi, Jouan; Ifaei, Pouya; Esfahani, Iman Janghorban; Ataei, Abtin; Yoo, Chang Kyoo

    2016-01-01

    Highlights: • Proposing two new power and cooling cogeneration systems based on absorption chillers and Kalina cycles. • Model-based comparison through thermodynamic and economic standpoints. • Investigating sensitivity of system performance and costs to the key parameters. • Reducing total annual costs of the base system up to 8% by cogeneration. • Increasing thermal efficiency up to 4.9% despite of cooling generation. - Abstract: Two new power and cooling cogeneration systems based on Kalina cycle (KC) and absorption refrigeration cycle (AC) are proposed and studied from thermodynamic and economic viewpoints. The first proposed system, Kalina power-cooling cycle (KPCC), combines the refrigerant loop of the water-ammonia absorption chiller, consisting of an evaporator and two throttling valves with the KC. A portion of the KC mass flow enters the evaporator to generate cooling after being condensed in the KPCC system. KPCC is a flexible system adapting power and cooling cogeneration to the demand. The second proposed system, Kalina lithium bromide absorption chiller cycle (KLACC), consists of the KC and a single effect lithium bromide-water absorption chiller (AC LiBr-water ). The KC subsystem discharges heat to the AC LiBr-water desorber before condensing in the condenser. The performance and economic aspects of both proposed systems are analyzed and compared with the stand alone KC. A parametric analysis is conducted to evaluate the sensitivity of efficiencies and the generated power and cooling quantities to the key operating variables. The results showed that, thermal efficiency and total annual costs decreased by 5.6% and 8% for KPCC system but increased 4.9% and 58% for KLACC system, respectively. Since the power-cooling efficiency of KLACC is 42% higher than KPCC it can be applied where the aim is cooling generation without considering economic aspects.

  8. The population of single and binary white dwarfs of the Galactic bulge

    Science.gov (United States)

    Torres, S.; García-Berro, E.; Cojocaru, R.; Calamida, A.

    2018-02-01

    Recent Hubble Space Telescope observations have unveiled the white dwarf cooling sequence of the Galactic bulge. Although the degenerate sequence can be well fitted employing the most up-to-date theoretical cooling sequences, observations show a systematic excess of red objects that cannot be explained by the theoretical models of single carbon-oxygen white dwarfs of the appropriate masses. Here we present a population synthesis study of the white dwarf cooling sequence of the Galactic bulge that takes into account the populations of both single white dwarfs and binary systems containing at least one white dwarf. These calculations incorporate state-of-the-art cooling sequences for white dwarfs with hydrogen-rich and hydrogen-deficient atmospheres, for both white dwarfs with carbon-oxygen and helium cores, and also take into account detailed prescriptions of the evolutionary history of binary systems. Our Monte Carlo simulator also incorporates all the known observational biases. This allows us to model with a high degree of realism the white dwarf population of the Galactic bulge. We find that the observed excess of red stars can be partially attributed to white dwarf plus main sequence binaries, and to cataclysmic variables or dwarf novae. Our best fit is obtained with a higher binary fraction and an initial mass function slope steeper than standard values, as well as with the inclusion of differential reddening and blending. Our results also show that the possible contribution of double degenerate systems or young and thick-disk bulge stars is negligible.

  9. Ages of galaxy bulges and disks from optical and near-infrared colours

    NARCIS (Netherlands)

    Peletier, RF; Balcells, M; Bender, R; Davies, RL

    1996-01-01

    For a sample of bright nearby early-type galaxies we have obtained surface photometry in bands ranging from U to K. Since the galaxies have inclinations larger than 50 degrees it is easy to separate bulges and disks. By measuring the colours in special regions, we minimize the effects of extinction,

  10. Photoionization modelling of planetary nebulae - II. Galactic bulge nebulae, a comparison with literature results

    NARCIS (Netherlands)

    van Hoof, PAM; Van de Steene, GC

    1999-01-01

    We have constructed photoionization models of five galactic bulge planetary nebulae using our automatic method, which enables a fully self-consistent determination of the physical parameters of a planetary nebula. The models are constrained using the spectrum, the IRAS and radio fluxes and the

  11. Genetically induced cell death in bulge stem cells reveals their redundancy for hair and epidermal regeneration.

    Science.gov (United States)

    Driskell, Iwona; Oeztuerk-Winder, Feride; Humphreys, Peter; Frye, Michaela

    2015-03-01

    Adult mammalian epidermis contains multiple stem cell populations in which quiescent and more proliferative stem and progenitor populations coexist. However, the precise interrelation of these populations in homeostasis remains unclear. Here, we blocked the contribution of quiescent keratin 19 (K19)-expressing bulge stem cells to hair follicle formation through genetic ablation of the essential histone methyltransferase Setd8 that is required for the maintenance of adult skin. Deletion of Setd8 eliminated the contribution of bulge cells to hair follicle regeneration through inhibition of cell division and induction of cell death, but the growth and morphology of hair follicles were unaffected. Furthermore, ablation of Setd8 in the hair follicle bulge blocked the contribution of K19-postive stem cells to wounded epidermis, but the wound healing process was unaltered. Our data indicate that quiescent bulge stem cells are dispensable for hair follicle regeneration and epidermal injury in the short term and support the hypothesis that quiescent and cycling stem cell populations are equipotent. © 2014 AlphaMed Press.

  12. Ages of galaxy bulges and disks from optical and near-infrared colors

    NARCIS (Netherlands)

    Peletier, RF; Balcells, M

    We compare optical and near-infrared colors of disks and bulges in a diameter-limited sample of inclined, bright, nearby, early-type spirals. Color profiles along wedge apertures at 15 degrees from the major axis and on the minor axis on the side of the galaxy opposite to the dust lane are used to

  13. SDSS-IV MaNGA: bulge-disc decomposition of IFU data cubes (BUDDI)

    Science.gov (United States)

    Johnston, Evelyn J.; Häußler, Boris; Aragón-Salamanca, Alfonso; Merrifield, Michael R.; Bamford, Steven; Bershady, Matthew A.; Bundy, Kevin; Drory, Niv; Fu, Hai; Law, David; Nitschelm, Christian; Thomas, Daniel; Roman Lopes, Alexandre; Wake, David; Yan, Renbin

    2017-02-01

    With the availability of large integral field unit (IFU) spectral surveys of nearby galaxies, there is now the potential to extract spectral information from across the bulges and discs of galaxies in a systematic way. This information can address questions such as how these components built up with time, how galaxies evolve and whether their evolution depends on other properties of the galaxy such as its mass or environment. We present bulge-disc decomposition of IFU data cubes (BUDDI), a new approach to fit the two-dimensional light profiles of galaxies as a function of wavelength to extract the spectral properties of these galaxies' discs and bulges. The fitting is carried out using GALFITM, a modified form of GALFIT which can fit multiwaveband images simultaneously. The benefit of this technique over traditional multiwaveband fits is that the stellar populations of each component can be constrained using knowledge over the whole image and spectrum available. The decomposition has been developed using commissioning data from the Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at APO (MaNGA) survey with redshifts z 22 arcsec, but can be applied to any IFU data of a nearby galaxy with similar or better spatial resolution and coverage. We present an overview of the fitting process, the results from our tests, and we finish with example stellar population analyses of early-type galaxies from the MaNGA survey to give an indication of the scientific potential of applying bulge-disc decomposition to IFU data.

  14. Planetary nebula velocities in the disc and bulge of M31

    NARCIS (Netherlands)

    Halliday, C.; Carter, D.; Bridges, T. J.; Jackson, Z. C.; Wilkinson, M. I.; Quinn, D. P.; Evans, N. W.; Douglas, N. G.; Merrett, H. R.; Merrifield, M. R.; Romanowsky, A. J.; Kuijken, K.; Irwin, M. J.

    2006-01-01

    We present radial velocities for a sample of 723 planetary nebulae in the disc and bulge of M31, measured using the WYFFOS fibre spectrograph on the William Herschel Telescope. Velocities are determined using the [OIII] lambda 5007 emission line. Rotation and velocity dispersion are measured to a

  15. Thermodynamic and Quantum Thermodynamic Analyses of Brownian Movement

    OpenAIRE

    Gyftopoulos, Elias P.

    2006-01-01

    Thermodynamic and quantum thermodynamic analyses of Brownian movement of a solvent and a colloid passing through neutral thermodynamic equilibrium states only. It is shown that Brownian motors and E. coli do not represent Brownian movement.

  16. Thermodynamics of nuclear materials

    International Nuclear Information System (INIS)

    1979-01-01

    Full text: The science of chemical thermodynamics has substantially contributed to the understanding of the many problems encountered in nuclear and reactor technology. These problems include reaction of materials with their surroundings and chemical and physical changes of fuels. Modern reactor technology, by its very nature, has offered new fields of investigations for the scientists and engineers concerned with the design of nuclear fuel elements. Moreover, thermodynamics has been vital in predicting the behaviour of new materials for fission as well as fusion reactors. In this regard, the Symposium was organized to provide a mechanism for review and discussion of recent thermodynamic investigations of nuclear materials. The Symposium was held in the Juelich Nuclear Research Centre, at the invitation of the Government of the Federal Republic of Germany. The International Atomic Energy Agency has given much attention to the thermodynamics of nuclear materials, as is evidenced by its sponsorship of four international symposia in 1962, 1965, 1967, and 1974. The first three meetings were primarily concerned with the fundamental thermodynamics of nuclear materials; as with the 1974 meeting, this last Symposium was primarily aimed at the thermodynamic behaviour of nuclear materials in actual practice, i.e., applied thermodynamics. Many advances have been made since the 1974 meeting, both in fundamental and applied thermodynamics of nuclear materials, and this meeting provided opportunities for an exchange of new information on this topic. The Symposium dealt in part with the thermodynamic analysis of nuclear materials under conditions of high temperatures and a severe radiation environment. Several sessions were devoted to the thermodynamic studies of nuclear fuels and fission and fusion reactor materials under adverse conditions. These papers and ensuing discussions provided a better understanding of the chemical behaviour of fuels and materials under these

  17. Ultra-deep GEMINI Near-infrared Observations of the Bulge Globular Cluster NGC 6624.

    Science.gov (United States)

    Saracino, S.; Dalessandro, E.; Ferraro, F. R.; Geisler, D.; Mauro, F.; Lanzoni, B.; Origlia, L.; Miocchi, P.; Cohen, R. E.; Villanova, S.; Moni Bidin, C.

    2016-11-01

    We used ultra-deep J and K s images secured with the near-infrared (NIR) GSAOI camera assisted by the multi-conjugate adaptive optics system GeMS at the GEMINI South Telescope in Chile, to obtain a (K s , J - K s ) color-magnitude diagram (CMD) for the bulge globular cluster NGC 6624. We obtained the deepest and most accurate NIR CMD from the ground for this cluster, by reaching K s ˜ 21.5, approximately 8 mag below the horizontal branch level. The entire extension of the Main Sequence (MS) is nicely sampled and at K s ˜ 20 we detected the so-called MS “knee” in a purely NIR CMD. By taking advantage of the exquisite quality of the data, we estimated the absolute age of NGC 6624 (t age = 12.0 ± 0.5 Gyr), which turns out to be in good agreement with previous studies in the literature. We also analyzed the luminosity and mass functions of MS stars down to M ˜ 0.45 M⊙, finding evidence of a significant increase of low-mass stars at increasing distances from the cluster center. This is a clear signature of mass segregation, confirming that NGC 6624 is in an advanced stage of dynamical evolution. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina). Based on observations gathered with ESO-VISTA telescope (program ID 179.B-2002).

  18. An application of the tensor virial theorem to hole + vortex + bulge systems

    Science.gov (United States)

    Caimmi, R.

    2009-04-01

    The tensor virial theorem for subsystems is formulated for three-component systems and further effort is devoted to a special case where the inner subsystems and the central region of the outer one are homogeneous, the last surrounded by an isothermal homeoid. The virial equations are explicitly written under the additional restrictions: (i) similar and similarly placed inner subsystems, and (ii) spherical outer subsystem. An application is made to hole + vortex + bulge systems, in the limit of flattened inner subsystems, which implies three virial equations in three unknowns. Using the Faber-Jackson relation, R∝σ02, the standard M- σ0 form (M∝σ04) is deduced from qualitative considerations. The projected bulge velocity dispersion to projected vortex velocity ratio, η=(σ)33/{[(v)qq]2+[(σ)qq]2}, as a function of the fractional radius, y=R/R, and the fractional masses, m=M/M and m=M/M, is studied in the range of interest, 0⩽m=M/M⩽5 [Escala, A., 2006. ApJ, 648, L13] and 229⩽m⩽795 [Marconi, A., Hunt, L.H., 2003. ApJ 589, L21], consistent with observations. The related curves appear to be similar to Maxwell velocity distributions, which implies a fixed value of η below the maximum corresponds to two different configurations: a compact bulge on the left of the maximum, and an extended bulge on the right. All curves lie very close one to the other on the left of the maximum, and parallel one to the other on the right. On the other hand, fixed m or m, and y, are found to imply more massive bulges passing from bottom to top along a vertical line on the (Oyη) plane, and vice versa. The model is applied to NGC 4374 and NGC 4486, taking the fractional mass, m, and the fractional radius, y, as unknowns, and the bulge mass is inferred from the knowledge of the hole mass, and compared with results from different methods. In presence of a massive vortex (m=5), the hole mass has to be reduced by a factor 2-3 with respect to the case of a massless vortex, to get

  19. Construction and functional characterization of double and triple mutants of parallel beta-bulge of ubiquitin.

    Science.gov (United States)

    Sharma, Mrinal; Prabha, C Ratna

    2011-12-01

    Ubiquitin, a small eukaryotic protein serving as a post-translational modification on many important proteins, plays central role in cellular homeostasis and cell cycle regulation. Ubiquitin features two beta-bulges, the second beta-bulge, located at the C-terminal region of the protein along with type II turn, holds 3 residues Glu64(1), Ser65(2) and Gln2(X). Percent frequency of occurrence of such a sequence in parallel beta-bulge is very low. However, the sequence and structure have been conserved in ubiquitin through out the evolution. Present study involves replacement of residues in unusual beta-bulge of ubiquitin by introducing mutations in combination through site directed mutagenesis, generating double and triple mutants and their functional characterization. Mutant ubiquitins cloned in yeast expression vector YEp96 tested for growth profile, viability assay and heat stress complementation study have revealed significant decrease in growth rate, loss of viability and non-complementation of heat sensitive phenotype with UbE64G-S65D and UbQ2N-E64G-S65D mutations. However, UbQ2N-S65D did not show any negative effects in the above assays. Present results show that, replacement of residues in beta-bulge of ubiquitin exerts severe effects on growth and viability in Saccharomyces cerevisiae due to functional failure of the mutant ubiquitins UbE64G-S65D and UbQ2N-E64G-S65D.

  20. First detection of the white dwarf cooling sequence of the galactic bulge

    International Nuclear Information System (INIS)

    Calamida, A.; Sahu, K. C.; Anderson, J.; Casertano, S.; Brown, T.; Sokol, J.; Bond, H. E.; Ferguson, H.; Livio, M.; Valenti, J.; Cassisi, S.; Buonanno, R.; Pietrinferni, A.; Salaris, M.; Ferraro, I.; Clarkson, W.

    2014-01-01

    We present Hubble Space Telescope data of the low-reddening Sagittarius window in the Galactic bulge. The Sagittarius Window Eclipsing Extrasolar Planet Search field (∼3'× 3'), together with three more Advanced Camera for Surveys and eight Wide-Field Camera 3 fields, were observed in the F606W and F814W filters, approximately every two weeks for 2 yr, with the principal aim of detecting a hidden population of isolated black holes and neutron stars through astrometric microlensing. Proper motions were measured with an accuracy of ≈0.1 mas yr –1 (≈4 km s –1 ) at F606W ≈ 25.5 mag, and better than ≈0.5 mas yr –1 (≈20 km s –1 ) at F606W ≈ 28 mag, in both axes. Proper-motion measurements allowed us to separate disk and bulge stars and obtain a clean bulge color-magnitude diagram. We then identified for the first time a white dwarf (WD) cooling sequence in the Galactic bulge, together with a dozen candidate extreme horizontal branch stars. The comparison between theory and observations shows that a substantial fraction of the WDs (≈30%) are systematically redder than the cooling tracks for CO-core H-rich and He-rich envelope WDs. This evidence would suggest the presence of a significant number of low-mass WDs and WD-main-sequence binaries in the bulge. This hypothesis is further supported by the finding of two dwarf novae in outburst, two short-period (P ≲ 1 day) ellipsoidal variables, and a few candidate cataclysmic variables in the same field.

  1. Lost in folding space? Comparing four variants of the thermodynamic model for RNA secondary structure prediction

    Directory of Open Access Journals (Sweden)

    Janssen Stefan

    2011-11-01

    Full Text Available Abstract Background Many bioinformatics tools for RNA secondary structure analysis are based on a thermodynamic model of RNA folding. They predict a single, "optimal" structure by free energy minimization, they enumerate near-optimal structures, they compute base pair probabilities and dot plots, representative structures of different abstract shapes, or Boltzmann probabilities of structures and shapes. Although all programs refer to the same physical model, they implement it with considerable variation for different tasks, and little is known about the effects of heuristic assumptions and model simplifications used by the programs on the outcome of the analysis. Results We extract four different models of the thermodynamic folding space which underlie the programs RNAFOLD, RNASHAPES, and RNASUBOPT. Their differences lie within the details of the energy model and the granularity of the folding space. We implement probabilistic shape analysis for all models, and introduce the shape probability shift as a robust measure of model similarity. Using four data sets derived from experimentally solved structures, we provide a quantitative evaluation of the model differences. Conclusions We find that search space granularity affects the computed shape probabilities less than the over- or underapproximation of free energy by a simplified energy model. Still, the approximations perform similar enough to implementations of the full model to justify their continued use in settings where computational constraints call for simpler algorithms. On the side, we observe that the rarely used level 2 shapes, which predict the complete arrangement of helices, multiloops, internal loops and bulges, include the "true" shape in a rather small number of predicted high probability shapes. This calls for an investigation of new strategies to extract high probability members from the (very large level 2 shape space of an RNA sequence. We provide implementations of all four

  2. Thermodynamics and heat power

    CERN Document Server

    Granet, Irving

    2014-01-01

    Fundamental ConceptsIntroductionThermodynamic SystemsTemperatureForce and MassElementary Kinetic Theory of GasesPressureReviewKey TermsEquations Developed in This ChapterQuestionsProblemsWork, Energy, and HeatIntroductionWorkEnergyInternal EnergyPotential EnergyKinetic EnergyHeatFlow WorkNonflow WorkReviewKey TermsEquations Developed in This ChapterQuestionsProblemsFirst Law of ThermodynamicsIntroductionFirst Law of ThermodynamicsNonflow SystemSteady-Flow SystemApplications of First Law of ThermodynamicsReviewKey TermsEquations Developed in This ChapterQuestionsProblemsThe Second Law of ThermodynamicsIntroductionReversibility-Second Law of ThermodynamicsThe Carnot CycleEntropyReviewKey TermsEquations Developed in This ChapterQuestionsProblemsProperties of Liquids and GasesIntroductionLiquids and VaporsThermodynamic Properties of SteamComputerized PropertiesThermodynamic DiagramsProcessesReviewKey TermsEquations Developed in This ChapterQuestionsProblemsThe Ideal GasIntroductionBasic ConsiderationsSpecific Hea...

  3. The thermodynamic solar energy

    International Nuclear Information System (INIS)

    Rivoire, B.

    2002-04-01

    The thermodynamic solar energy is the technic in the whole aiming to transform the solar radiation energy in high temperature heat and then in mechanical energy by a thermodynamic cycle. These technic are most often at an experimental scale. This paper describes and analyzes the research programs developed in the advanced countries, since 1980. (A.L.B.)

  4. Force fields for monovalent and divalent metal cations in TIP3P water based on thermodynamic and kinetic properties

    Science.gov (United States)

    Mamatkulov, Shavkat; Schwierz, Nadine

    2018-02-01

    Metal cations are essential in many vital processes. In order to capture the role of different cations in all-atom molecular dynamics simulations of biological processes, an accurate parametrization is crucial. Here, we develop force field parameters for the metal cations Li+, Na+, K+, Cs+, Mg2+, Ca2+, Sr2+, and Ba2+ in combination with the TIP3P water model that is frequently used in biomolecular simulations. In progressing toward improved force fields, the approach presented here is an extension of previous efforts and allows us to simultaneously reproduce thermodynamic and kinetic properties of aqueous solutions. We systematically derive the parameters of the 12-6 Lennard-Jones potential which accurately reproduces the experimental solvation free energy, the activity derivative, and the characteristics of water exchange from the first hydration shell of the metal cations. In order to reproduce all experimental properties, a modification of the Lorentz-Berthelot combination rule is required for Mg2+. Using a balanced set of solution properties, the optimized force field parameters aim to capture the fine differences between distinct metal cations including specific ion binding affinities and the kinetics of cation binding to biologically important anionic groups.

  5. Alloy Design Based on Computational Thermodynamics and Multi-objective Optimization: The Case of Medium-Mn Steels

    Science.gov (United States)

    Aristeidakis, John S.; Haidemenopoulos, Gregory N.

    2017-05-01

    A new alloy design methodology is presented for the identification of alloy compositions, which exhibit process windows (PWs) satisfying specific design objectives and optimized for overall performance. The methodology is applied to the design of medium-Mn steels containing Al and/or Ni. By implementing computational alloy thermodynamics, a large composition space was investigated systematically to map the fraction and stability of retained austenite as a function of intercritical annealing temperature. Alloys exhibiting PWs, i.e., an intercritical annealing range, which when applied satisfies the given design objectives, were identified. A multi-objective optimization method, involving Pareto optimality, was then applied to identify a list of optimum alloy compositions, which maximized retained austenite amount and stability, as well as intercritical annealing temperature, while minimized overall alloy content. A heuristic approach was finally employed in order to rank the optimum alloys. The methodology provided a final short list of alloy compositions and associated PWs ranked according to their overall performance. The proposed methodology could be the first step in the process of computational alloy design of medium-Mn steels or other alloy systems.

  6. Equilibrium thermodynamics - Callen's postulational approach

    NARCIS (Netherlands)

    Jongschaap, R.J.J.; Öttinger, Hans Christian

    2001-01-01

    In order to provide the background for nonequilibrium thermodynamics, we outline the fundamentals of equilibrium thermodynamics. Equilibrium thermodynamics must not only be obtained as a special case of any acceptable nonequilibrium generalization but, through its shining example, it also elucidates

  7. Applied chemical engineering thermodynamics

    CERN Document Server

    Tassios, Dimitrios P

    1993-01-01

    Applied Chemical Engineering Thermodynamics provides the undergraduate and graduate student of chemical engineering with the basic knowledge, the methodology and the references he needs to apply it in industrial practice. Thus, in addition to the classical topics of the laws of thermodynamics,pure component and mixture thermodynamic properties as well as phase and chemical equilibria the reader will find: - history of thermodynamics - energy conservation - internmolecular forces and molecular thermodynamics - cubic equations of state - statistical mechanics. A great number of calculated problems with solutions and an appendix with numerous tables of numbers of practical importance are extremely helpful for applied calculations. The computer programs on the included disk help the student to become familiar with the typical methods used in industry for volumetric and vapor-liquid equilibria calculations.

  8. Thermodynamics an engineering approach

    CERN Document Server

    Cengel, Yunus A

    2014-01-01

    Thermodynamics, An Engineering Approach, eighth edition, covers the basic principles of thermodynamics while presenting a wealth of real-world engineering examples so students get a feel for how thermodynamics is applied in engineering practice. This text helps students develop an intuitive understanding by emphasizing the physics and physical arguments. Cengel and Boles explore the various facets of thermodynamics through careful explanations of concepts and use of numerous practical examples and figures, having students develop necessary skills to bridge the gap between knowledge and the confidence to properly apply their knowledge. McGraw-Hill is proud to offer Connect with the eighth edition of Cengel/Boles, Thermodynamics, An Engineering Approach. This innovative and powerful new system helps your students learn more efficiently and gives you the ability to assign homework problems simply and easily. Problems are graded automatically, and the results are recorded immediately. Track individual stude...

  9. Thermodynamics of complexity

    DEFF Research Database (Denmark)

    Westerhoff, Hans V.; Jensen, Peter Ruhdal; Snoep, Jacky L.

    1998-01-01

    Thermodynamics has always been a remarkable science in that it studies macroscopic properties that are only partially determined by the properties of individual molecules. Entropy and free energy only exist in constellations of more than a single molecule (degree of freedom). They are the so...... understanding of this BioComplexity, modem thermodynamic concepts and methods (nonequilibrium thermodynamics, metabolic and hierarchical control analysis) will be needed. We shall propose to redefine nonequilibrium thermodynamics as: The science that aims at understanding the behaviour of nonequilibrium systems...... by taking into account both the molecular properties and the emergent properties that are due to (dys)organisation. This redefinition will free nonequilibrium thermodynamics from the limitations imposed by earlier near-equilibrium assumptions, resolve the duality with kinetics, and bridge the apparent gap...

  10. The thermodynamics of extraction of U(VI) and Th(IV) from nitric acid by neutral phosphorus-based organic compounds

    International Nuclear Information System (INIS)

    Kalina, D.G.; Mason, G.W.; Horwitz, E.P.

    1981-01-01

    The extraction of Th(IV) and U(VI) from dilute nitric acid solution by several neutral phosphorus-based extractants has been studied as a function of temperature in the range of 0 to 50 0 C. From the variation of the distribution ratio (Ksub(d)) with temperature the thermodynamic quantities ΔG, ΔH and ΔS have been calculated for these extractions. The results of this study indicate that the steric bulk of the extractant plays a major role in determining how well Th(IV) is extracted. The size of the extractant appears to be of little or no importance in the extraction of U(VI). Similarly, the basicity of the extractant is of lesser importance in the extraction of uranyl ion relative to thorium ion. (author)

  11. Microcanonical ensemble extensive thermodynamics of Tsallis statistics

    International Nuclear Information System (INIS)

    Parvan, A.S.

    2005-01-01

    The microscopic foundation of the generalized equilibrium statistical mechanics based on the Tsallis entropy is given by using the Gibbs idea of statistical ensembles of the classical and quantum mechanics.The equilibrium distribution functions are derived by the thermodynamic method based upon the use of the fundamental equation of thermodynamics and the statistical definition of the functions of the state of the system. It is shown that if the entropic index ξ = 1/q - 1 in the microcanonical ensemble is an extensive variable of the state of the system, then in the thermodynamic limit z bar = 1/(q - 1)N = const the principle of additivity and the zero law of thermodynamics are satisfied. In particular, the Tsallis entropy of the system is extensive and the temperature is intensive. Thus, the Tsallis statistics completely satisfies all the postulates of the equilibrium thermodynamics. Moreover, evaluation of the thermodynamic identities in the microcanonical ensemble is provided by the Euler theorem. The principle of additivity and the Euler theorem are explicitly proved by using the illustration of the classical microcanonical ideal gas in the thermodynamic limit

  12. Microcanonical ensemble extensive thermodynamics of Tsallis statistics

    International Nuclear Information System (INIS)

    Parvan, A.S.

    2006-01-01

    The microscopic foundation of the generalized equilibrium statistical mechanics based on the Tsallis entropy is given by using the Gibbs idea of statistical ensembles of the classical and quantum mechanics. The equilibrium distribution functions are derived by the thermodynamic method based upon the use of the fundamental equation of thermodynamics and the statistical definition of the functions of the state of the system. It is shown that if the entropic index ξ=1/(q-1) in the microcanonical ensemble is an extensive variable of the state of the system, then in the thermodynamic limit z-bar =1/(q-1)N=const the principle of additivity and the zero law of thermodynamics are satisfied. In particular, the Tsallis entropy of the system is extensive and the temperature is intensive. Thus, the Tsallis statistics completely satisfies all the postulates of the equilibrium thermodynamics. Moreover, evaluation of the thermodynamic identities in the microcanonical ensemble is provided by the Euler theorem. The principle of additivity and the Euler theorem are explicitly proved by using the illustration of the classical microcanonical ideal gas in the thermodynamic limit

  13. Multi-objective thermodynamic-based optimization of output power of Solar Dish-Stirling engine by implementing an evolutionary algorithm

    International Nuclear Information System (INIS)

    Ahmadi, Mohammad H.; Mohammadi, Amir H.; Dehghani, Saeed; Barranco-Jiménez, Marco A.

    2013-01-01

    Highlights: • Finite time thermodynamic modeling of a Stirling engine is presented. • Thermal efficiency and output power of the engine are maximized and entropy generation is minimized simultaneously. • Pareto optimal frontier is obtained using the NSGA-II. • A final optimal solution is selected using LINMAP, TOPSIS and Bellman–Zadeh decision making methods. - Abstract: A solar-powered high temperature differential Stirling engine has been considered for optimization with multiple criteria. A mathematical model based on the finite-time thermodynamics has been developed so that the output power and thermal efficiency and the rate of entropy generation of the solar Stirling system with finite rate of heat transfer, regenerative heat loss, conductive thermal bridging loss and finite regeneration process time are obtained. Furthermore, imperfect performance of the dish collector and convective/radiative heat transfer mechanisms at the hot end as well as the convective heat transfer at the heat sink of the engine are considered in the developed model. Three objective functions including the output power and overall thermal efficiency have been considered simultaneously for maximization and the rate of entropy generation of the Stirling engine are minimized at the same time. Multi-objective evolutionary algorithms (MOEAs) based on NSGA-II algorithm has been employed while the Effectiveness’s of regenerator, the Effectiveness’s of the low temperature heat exchanger, the Effectiveness’s of the high temperature heat exchanger, heat capacitance rate of the heat sink, heat capacitance rate of the heat source, temperatures of the working fluid in the high temperature isothermal process and temperatures of the working fluid in the low temperature isothermal process are considered as decision variables. Pareto optimal frontier has been obtained and a final optimal solution has been selected using various decision-making approaches including the fuzzy Bellman

  14. Sediment budget on African passive margins: a record of margin bulges and far field very long wavelength deformations

    Science.gov (United States)

    Guillocheau, Francois; Robin, Cécile; Baby, Guillaume; Simon, Brendan; Rouby, Delphine; Loparev, Artiom

    2017-04-01

    The post-rift siliciclastic sediment budget of passive margins is a function of (1) the deformation (uplift) of the upstream catchment, of (2) the climate (precipitation) regime and of (3) the oceanic circulation (mainly since Miocene times). The main questions in source to sink studies are (1) to quantify the relative importance of the erosion due to uplifts or to precipitation changes and (2) to characterize the source of the sediments. A source to sink study was carried out in Western, Central and Austral Africa, characterized by anorogenic relief (plains and plateaus) that record long (several 100 km) to very long (several 1000 km) wavelength deformations respectively of lithospheric and mantle origin. The sink measurement was based on seismic lines and wells (industrial - IODP) using the VolumeEstimator software including the calculation of the uncertainties (Guillocheau et al., 2013, Basin Research). The source study was performed using dated stepped planation surfaces (etchplains and pediplains), mappable at catchments-scale (Guillocheau et al., in press, Gondwana Research). Results: (1) Deformation (uplift) is the dominant control of the sediment budget. Climate (precipitation) changes only enhance or inhibit a deformation-controlled flux. (2) The sources of siliciclastic sediments are either closed marginal bulges or far field domes due to mantle dynamics with river by-passing over long-lasting polygenic surfaces located between the bulges and domes. Two main periods of African-scale deformations (contemporaneous with an increase of the sedimentary flux) are confirmed, one during Late Cretaceous (Turonian-Coniacian) and the second around the Eocene-Oligocene boundary with a gap and intense chemical erosion from 75 Ma and mainly from 65 to 40 Ma.

  15. Entropy and energy quantization: Planck thermodynamic calculation

    International Nuclear Information System (INIS)

    Mota e Albuquerque, Ivone Freire da.

    1988-01-01

    This dissertation analyses the origins and development of the concept of entropy and its meaning of the second Law of thermodynamics, as well as the thermodynamics derivation of the energy quantization. The probabilistic interpretation of that law and its implication in physics theory are evidenciated. Based on Clausius work (which follows Carnot's work), we analyse and expose in a original way the entropy concept. Research upon Boltzmann's work and his probabilistic interpretation of the second Law of thermodynamics is made. The discuss between the atomistic and the energeticist points of view, which were actual at that time are also commented. (author). 38 refs., 3 figs

  16. Thermodynamics and economics

    International Nuclear Information System (INIS)

    Mansson, B.A.

    1990-01-01

    Economics, as the social science most concerned with the use and distribution of natural resources, must start to make use of the knowledge at hand in the natural sciences about such resources. In this, thermodynamics is an essential part. In a physicists terminology, human economic activity may be described as a dissipative system which flourishes by transforming and exchanging resources, goods and services. All this involves complex networks of flows of energy and materials. This implies that thermodynamics, the physical theory of energy and materials flows, must have implications for economics. On another level, thermodynamics has been recognized as a physical theory of value, with value concepts similar to those of economic theory. This paper discusses some general aspects of the significance of non-equilibrium thermodynamics for economics. The role of exergy, probably the most important of the physical measures of value, is elucidated. Two examples of integration of thermodynamics with economic theory are reviewed. First, a simple model of a steady-state production system is sued to illustrate the effects of thermodynamic process constraints. Second, the framework of a simple macroeconomic growth model is used to illustrate how some thermodynamic limitations may be integrated in macroeconomic theory

  17. CHEMICAL EVOLUTION OF THE INNER 2 DEGREES OF THE MILKY WAY BULGE: [α/Fe] TRENDS AND METALLICITY GRADIENTS

    International Nuclear Information System (INIS)

    Ryde, N.; Schultheis, M.; Grieco, V.; Matteucci, F.; Rich, R. M.; Uttenthaler, S.

    2016-01-01

    The structure, formation, and evolution of the Milky Way bulge is a matter of debate. Important diagnostics for discriminating between models of bulge formation and evolution include α-abundance trends with metallicity, and spatial abundance and metallicity gradients. Due to the severe optical extinction in the inner Bulge region, only a few detailed investigations of this region have been performed. Here we aim at investigating the inner 2 degrees of the Bulge (projected galactocentric distance of approximately 300 pc), rarely investigated before, by observing the [α/Fe] element trends versus metallicity, and by trying to derive the metallicity gradient in the b < 2° region. [α/Fe] and metallicities have been determined by spectral synthesis of 2 μm spectra of 28 M-giants in the Bulge, lying along the southern minor axis at (l, b) = (0, 0), (0, −1°), and (0, −2°). These were observed with the CRIRES spectrometer at the Very Large Telescope, (VLT) at high spectral resolution. Low-resolution K-band spectra, observed with the ISAAC spectrometer at the VLT, are used to determine the effective temperature of the stars. We present the first connection between the Galactic center (GC) and the Bulge using similar stars, high spectral resolution, and analysis techniques. The [α/Fe] trends in all our three fields show a large similarity among each other and with trends further out in the Bulge. All point to a rapid star formation episode in the Bulge. We find that there is a lack of an [α/Fe] gradient in the Bulge all the way into the center, suggesting a homogeneous Bulge when it comes to the enrichment process and star formation history. We find a large range of metallicities from −1.2 < [Fe/H] < +0.3, with a lower dispersion in the GC: −0.2 < [Fe/H] < +0.3. The derived metallicities of the stars in the three fields get, in the mean, progressively higher the closer to the Galactic plane they lie. We could interpret this as a continuation of the

  18. Modern engineering thermodynamics

    CERN Document Server

    Balmer, Robert T

    2010-01-01

    Designed for use in a standard two-semester engineering thermodynamics course sequence. The first half of the text contains material suitable for a basic Thermodynamics course taken by engineers from all majors. The second half of the text is suitable for an Applied Thermodynamics course in mechanical engineering programs. The text has numerous features that are unique among engineering textbooks, including historical vignettes, critical thinking boxes, and case studies. All are designed to bring real engineering applications into a subject that can be somewhat abstract and mathematica

  19. Non-equilibrium thermodynamics

    CERN Document Server

    De Groot, Sybren Ruurds

    1984-01-01

    The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn

  20. Thermodynamics I essentials

    CERN Document Server

    REA, The Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Thermodynamics I includes review of properties and states of a pure substance, work and heat, energy and the first law of thermodynamics, entropy and the second law of thermodynamics

  1. A Thermodynamically-Based Mesh Objective Work Potential Theory for Predicting Intralaminar Progressive Damage and Failure in Fiber-Reinforced Laminates

    Science.gov (United States)

    Pineda, Evan J.; Waas, Anthony M.

    2012-01-01

    A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Damage is considered to be the effect of any structural changes in a material that manifest as pre-peak non-linearity in the stress versus strain response. Conversely, failure is taken to be the effect of the evolution of any mechanisms that results in post-peak strain softening. It is assumed that matrix microdamage is the dominant damage mechanism in continuous fiber-reinforced polymer matrix laminates, and its evolution is controlled with a single ISV. Three additional ISVs are introduced to account for failure due to mode I transverse cracking, mode II transverse cracking, and mode I axial failure. Typically, failure evolution (i.e., post-peak strain softening) results in pathologically mesh dependent solutions within a finite element method (FEM) setting. Therefore, consistent character element lengths are introduced into the formulation of the evolution of the three failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs is derived. The theory is implemented into commercial FEM software. Objectivity of total energy dissipated during the failure process, with regards to refinements in the FEM mesh, is demonstrated. The model is also verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared to the experiments.

  2. Theoretical physics 5 thermodynamics

    CERN Document Server

    Nolting, Wolfgang

    2017-01-01

    This concise textbook offers a clear and comprehensive introduction to thermodynamics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series, defining macroscopic variables, such as internal energy, entropy and pressure,together with thermodynamic principles. The first part of the book introduces the laws of thermodynamics and thermodynamic potentials. More complex themes are covered in the second part of the book, which describes phases and phase transitions in depth. Ideally suited to undergraduate students with some grounding in classical mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this series cove...

  3. Polyelectrolytes thermodynamics and rheology

    CERN Document Server

    P M, Visakh; Picó, Guillermo Alfredo

    2014-01-01

    This book discusses current development of theoretical models and experimental findings on the thermodynamics of polyelectrolytes. Particular emphasis is placed on the rheological description of polyelectrolyte solutions and hydrogels.

  4. Workshop on Teaching Thermodynamics

    CERN Document Server

    1985-01-01

    It seemed appropriate to arrange a meeting of teachers of thermodynamics in the United Kingdom, a meeting held in the pleasant surroundings of Emmanuel College, Cambridge, in Sept~mber, 1984. This volume records the ideas put forward by authors, the discussion generated and an account of the action that discussion has initiated. Emphasis was placed on the Teaching of Thermodynamics to degree-level students in their first and second years. The meeting, a workshop for practitioners in which all were expected to take part, was remarkably well supported. This was notable in the representation of essentially every UK university and polytechnic engaged in teaching engineering thermodynamics and has led to a stimulating spread of ideas. By intention, the emphasis for attendance was put on teachers of engineering concerned with thermodynamics, both mechanical and chemical engineering disciplines. Attendance from others was encouraged but limited as follows: non-engineering acad­ emics, 10%, industrialists, 10%. The ...

  5. General and Statistical Thermodynamics

    CERN Document Server

    Tahir-Kheli, Raza

    2012-01-01

    This textbook explains completely the general and statistical thermodynamics. It begins with an introductory statistical mechanics course, deriving all the important formulae meticulously and explicitly, without mathematical short cuts. The main part of the book deals with the careful discussion of the concepts and laws of thermodynamics, van der Waals, Kelvin and Claudius theories, ideal and real gases, thermodynamic potentials, phonons and all the related aspects. To elucidate the concepts introduced and to provide practical problem solving support, numerous carefully worked examples are of great value for students. The text is clearly written and punctuated with many interesting anecdotes. This book is written as main textbook for upper undergraduate students attending a course on thermodynamics.

  6. Elements of statistical thermodynamics

    CERN Document Server

    Nash, Leonard K

    2006-01-01

    Encompassing essentially all aspects of statistical mechanics that appear in undergraduate texts, this concise, elementary treatment shows how an atomic-molecular perspective yields new insights into macroscopic thermodynamics. 1974 edition.

  7. Elements of chemical thermodynamics

    CERN Document Server

    Nash, Leonard K

    2005-01-01

    This survey of purely thermal data in calculating the position of equilibrium in a chemical reaction highlights the physical content of thermodynamics, as distinct from purely mathematical aspects. 1970 edition.

  8. Electrochemical thermodynamic measurement system

    Science.gov (United States)

    Reynier, Yvan [Meylan, FR; Yazami, Rachid [Los Angeles, CA; Fultz, Brent T [Pasadena, CA

    2009-09-29

    The present invention provides systems and methods for accurately characterizing thermodynamic and materials properties of electrodes and electrochemical energy storage and conversion systems. Systems and methods of the present invention are configured for simultaneously collecting a suite of measurements characterizing a plurality of interconnected electrochemical and thermodynamic parameters relating to the electrode reaction state of advancement, voltage and temperature. Enhanced sensitivity provided by the present methods and systems combined with measurement conditions that reflect thermodynamically stabilized electrode conditions allow very accurate measurement of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions, that enable prediction of important performance attributes of electrode materials and electrochemical systems, such as the energy, power density, current rate and the cycle life of an electrochemical cell.

  9. X-ray bursters and the X-ray sources of the galactic bulge

    Science.gov (United States)

    Lewin, W. H. G.; Joss, P. C.

    An attempt is made to distill from observational and theoretical information on the galactic bulge X-ray sources in general, and on the X-ray burst sources in particular, those aspects which seem to have the greatest relevance to the understanding of these sources. Galactic bulge sources appear to be collapsed objects of roughly solar mass, in most cases neutron stars, which are accreting matter from low-mass stellar companions. Type I bursts seem to result from thermonuclear flashes in the surface layers of some of these neutron stars, while the type II bursts from the Rapid Burster are almost certainly due to an instability in the accretion flow onto a neutron star. It is concluded that the studies cited offer a new and powerful observational handle on the fundamental properties of neutron stars and of the interacting binary systems in which they are often contained.

  10. VVV: The near-IR Milky Way bulge and plane survey*

    Directory of Open Access Journals (Sweden)

    Lucas P.

    2012-02-01

    Full Text Available The ESO public survey “VISTA Variables in the Via Lactea” (VVV started mapping the inner disk and bulge of our Galaxy with the VISTA 4m telescope in the near-IR in 2010. The planned survey area of 520 deg2 is observed in the Z, Y, J, H and Ks filters, and in addition more than 100 epochs of repeated imaging in Ks will be collected over ∼5 years. The final products will be a deep near-IR atlas in five passbands, and catalogue of more than a million variable sources. This public survey will provide data available to the whole community and therefore will enable further studies of the history of the Milky Way, its star cluster evolution, and the population census of the Galactic Bulge and center, as well as the investigations of the star formation regions in the disk.

  11. Thermodynamics and quantum correlations

    OpenAIRE

    Perarnau Llobet, Martí

    2016-01-01

    Thermodynamics traditionally deals with macroscopic systems at thermal equilibrium. However, since the very beginning of the theory, its range of applicability has only increased, nowadays being applied to virtually every field of science, and to systems of extremely different size. This thesis is devoted to the study of thermodynamics in the quantum regime. It contains original results on topics that include: Work extraction from quantum systems, fluctuations of work, the energetic valu...

  12. Iran’s Youth Bulge and It’s Implications for U.S. National Security

    Science.gov (United States)

    2006-04-01

    the rest of the region shares similar if not worse youth unemployment problems. 10 Thus, “…most theoretical works concerned with youth bulges... youth unemployment must be estimated, interpolated, or guessed. Some analysts use per capita gross national product (GNP), per capita gross domestic...poor urban dwellers turn to Islamic extremism, which in turn leads to political instability. A major barrier that precludes definitively linking youth

  13. An Optimal Strategy for Accurate Bulge-to-disk Decomposition of Disk Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Gao Hua [Department of Astronomy, School of Physics, Peking University, Beijing 100871 (China); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2017-08-20

    The development of two-dimensional (2D) bulge-to-disk decomposition techniques has shown their advantages over traditional one-dimensional (1D) techniques, especially for galaxies with non-axisymmetric features. However, the full potential of 2D techniques has yet to be fully exploited. Secondary morphological features in nearby disk galaxies, such as bars, lenses, rings, disk breaks, and spiral arms, are seldom accounted for in 2D image decompositions, even though some image-fitting codes, such as GALFIT, are capable of handling them. We present detailed, 2D multi-model and multi-component decomposition of high-quality R -band images of a representative sample of nearby disk galaxies selected from the Carnegie-Irvine Galaxy Survey, using the latest version of GALFIT. The sample consists of five barred and five unbarred galaxies, spanning Hubble types from S0 to Sc. Traditional 1D decomposition is also presented for comparison. In detailed case studies of the 10 galaxies, we successfully model the secondary morphological features. Through a comparison of best-fit parameters obtained from different input surface brightness models, we identify morphological features that significantly impact bulge measurements. We show that nuclear and inner lenses/rings and disk breaks must be properly taken into account to obtain accurate bulge parameters, whereas outer lenses/rings and spiral arms have a negligible effect. We provide an optimal strategy to measure bulge parameters of typical disk galaxies, as well as prescriptions to estimate realistic uncertainties of them, which will benefit subsequent decomposition of a larger galaxy sample.

  14. Low temperature deformation behavior of an electromagnetically bulged 5052 aluminum alloy

    OpenAIRE

    Zu Li; Ning Li; Duzhen Wang; Di Ouyang; Lin Liu

    2016-01-01

    The fundamental understanding of the deformation behavior of electromagnetically formed metallic components under extreme conditions is important. Here, the effect of low temperature on the deformation behavior of an electromagnetically-bulged 5052 aluminum alloy was investigated through uniaxial tension. We found that the Portevin-Le Chatelier Effect, designated by the serrated characteristic in stress-strain curves, continuously decays until completely disappears with decreasing temperature...

  15. Geometry and symmetry in non-equilibrium thermodynamic systems

    Science.gov (United States)

    Sonnino, Giorgio

    2017-06-01

    The ultimate aim of this series of works is to establish the closure equations, valid for thermodynamic systems out from the Onsager region, and to describe the geometry and symmetry in thermodynamic systems far from equilibrium. Geometry of a non-equilibrium thermodynamic system is constructed by taking into account the second law of thermodynamics and by imposing the validity of the Glansdorff-Prigogine Universal Criterion of Evolution. These two constraints allow introducing the metrics and the affine connection of the Space of the Thermodynamic Forces, respectively. The Lie group associated to the nonlinear Thermodynamic Coordinate Transformations (TCT) leaving invariant both the entropy production σ and the Glansdorff-Prigogine dissipative quantity P, is also described. The invariance under TCT leads to the formulation of the Thermodynamic Covariance Principle (TCP): The nonlinear closure equations, i.e. the flux-force relations, must be covariant under TCT. In other terms, the fundamental laws of thermodynamics should be manifestly covariant under transformations between the admissible thermodynamic forces (i.e. under TCT). The symmetry properties of a physical system are intimately related to the conservation laws characterizing the thermodynamic system. Noether's theorem gives a precise description of this relation. The macroscopic theory for closure relations, based on this geometrical description and subject to the TCP, is referred to as the Thermodynamic Field Theory (TFT). This theory ensures the validity of the fundamental theorems for systems far from equilibrium.

  16. Mechanics of membrane bulging during cell-wall disruption in Gram-negative bacteria

    Science.gov (United States)

    Daly, Kristopher E.; Huang, Kerwyn Casey; Wingreen, Ned S.; Mukhopadhyay, Ranjan

    2011-04-01

    The bacterial cell wall is a network of sugar strands crosslinked by peptides that serve as the primary structure for bearing osmotic stress. Despite its importance in cellular survival, the robustness of the cell wall to network defects has been relatively unexplored. Treatment of the Gram-negative bacterium Escherichia coli with the antibiotic vancomycin, which disrupts the crosslinking of new material during growth, leads to the development of pronounced bulges and eventually of cell lysis. Here, we model the mechanics of the bulging of the cytoplasmic membrane through pores in the cell wall. We find that the membrane undergoes a transition between a nearly flat state and a spherical bulge at a critical pore radius of ~20 nm. This critical pore size is large compared to the typical distance between neighboring peptides and glycan strands, and hence pore size acts as a constraint on network integrity. We also discuss the general implications of our model to membrane deformations in eukaryotic blebbing and vesiculation in red blood cells.

  17. Reduction of lower palpebral bulge by plicating attenuated orbital septa: a technical modification in cosmetic blepharoplasty.

    Science.gov (United States)

    Huang, T

    2000-06-01

    Bulging of the lower eyelid is regarded as a sign of aging. "Herniation" of the periorbital fat pads is traditionally regarded as the factor responsible for the change. Excision of fat pads, therefore, has been the mainstay of treatment in reducing the palpebral bulge in cosmetic blepharoplasty. The surgical excision of"excess" and "herniated" fat pads, however, causes problems such as lid ecchymosis, chemosis, lid contour irregularity, ectropion, and retrobulbar hematoma formation. The author proposes that the loss of fat pad support caused by the attenuation of the orbital septa, not herniation of the excess fat pads, is the major factor responsible for the bulge. The author further proposes that the functional integrity of the orbital septum can be restored by plicating the attenuated orbital septa with 5-0 absorbable sutures. This technique of invaginating the protruded fat pad was performed in 138 individuals (276 lower eyelids). The operation was technically simple, and the approach was "tissue friendly." The results obtained, with the exception of a mild degree of puffiness encountered soon after the surgery, were satisfactory. Morbidity was minimal.

  18. Quantitative fetal fibronectin predicts preterm birth in women with bulging fetal membranes.

    Science.gov (United States)

    Fiorini, Francesco; Isted, Alexander; Hezelgrave, Natasha L; Shennan, Andrew H

    2016-08-01

    To assess the predictive value of quantitative fetal fibronectin (fFN) concentration in cervicovaginal fluid for spontaneous preterm birth in women with bulging fetal membranes. This was a prospective observational study from five UK tertiary centres of a cohort of women with singleton pregnancy and bulging fetal membranes presenting between 18 and 32 weeks of gestation (n=62), in the period 2010-2014. fFN concentrations in cervicovaginal fluid were measured both quantitatively and qualitatively at presentation in all women. Predictive statistics and receiver operating characteristic (ROC) curves were calculated for both tests to predict spontaneous preterm birth within 14 days from testing and before 34 weeks of gestation. 62 eligible women with bulging fetal membranes were recruited from screening of 2571 women at high risk of preterm birth. The median gestational age was 24(+0) (LQ-UQ, 21(+2)-25(+3)) at presentation and 34(+4) (25(+2)-39(+0)) at delivery, with a median time from testing to delivery of 58 days (17-110). Concentration of quantitative fFN at presentation correlated negatively with time to delivery (Spearman's rs=-0.615, pmembranes, suggesting that fFN leakage could potentially be an active process. This may aid the clinical management of this high-risk group in the future. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Star formation history of the Galactic bulge from deep HST imaging of low reddening windows

    Science.gov (United States)

    Bernard, Edouard J.; Schultheis, Mathias; Di Matteo, Paola; Hill, Vanessa; Haywood, Misha; Calamida, Annalisa

    2018-04-01

    Despite the huge amount of photometric and spectroscopic efforts targetting the Galactic bulge over the past few years, its age distribution remains controversial owing to both the complexity of determining the age of individual stars and the difficult observing conditions. Taking advantage of the recent release of very deep, proper-motion-cleaned colour-magnitude diagrams (CMDs) of four low reddening windows obtained with the Hubble Space Telescope (HST), we used the CMD-fitting technique to calculate the star formation history (SFH) of the bulge at -2° > b > -4° along the minor axis. We find that over 80 percent of the stars formed before 8 Gyr ago, but that a significant fraction of the super-solar metallicity stars are younger than this age. Considering only the stars that are within reach of the current generation of spectrographs (i.e. V≲ 21), we find that 10 percent of the bulge stars are younger than 5 Gyr, while this fraction rises to 20-25 percent in the metal-rich peak. The age-metallicity relation is well parametrized by a linear fit implying an enrichment rate of dZ/dt ˜ 0.005 Gyr-1. Our metallicity distribution function accurately reproduces that observed by several spectroscopic surveys of Baade's window, with the bulk of stars having metal-content in the range [Fe/H]˜-0.7 to ˜0.6, along with a sparse tail to much lower metallicities.

  20. The population of single and binary white dwarfs of the Galactic bulge

    Science.gov (United States)

    Torres, S.; García-Berro, E.; Cojocaru, R.; Calamida, A.

    2018-05-01

    Recent Hubble Space Telescope observations have unveiled the white dwarf cooling sequence of the Galactic bulge. Although the degenerate sequence can be well fitted employing the most up-to-date theoretical cooling sequences, observations show a systematic excess of red objects that cannot be explained by the theoretical models of single carbon-oxygen white dwarfs of the appropriate masses. Here, we present a population synthesis study of the white dwarf cooling sequence of the Galactic bulge that takes into account the populations of both single white dwarfs and binary systems containing at least one white dwarf. These calculations incorporate state-of-the-art cooling sequences for white dwarfs with hydrogen-rich and hydrogen-deficient atmospheres, for both white dwarfs with carbon-oxygen and helium cores, and also take into account detailed prescriptions of the evolutionary history of binary systems. Our Monte Carlo simulator also incorporates all the known observational biases. This allows us to model with a high degree of realism the white dwarf population of the Galactic bulge. We find that the observed excess of red stars can be partially attributed to white dwarf plus main sequence binaries, and to cataclysmic variables or dwarf novae. Our best fit is obtained with a higher binary fraction and an initial mass function slope steeper than standard values, as well as with the inclusion of differential reddening and blending. Our results also show that the possible contribution of double degenerate systems or young and thick-discbulge stars is negligible.

  1. Simulated pressure denaturation thermodynamics of ubiquitin.

    Science.gov (United States)

    Ploetz, Elizabeth A; Smith, Paul E

    2017-12-01

    Simulations of protein thermodynamics are generally difficult to perform and provide limited information. It is desirable to increase the degree of detail provided by simulation and thereby the potential insight into the thermodynamic properties of proteins. In this study, we outline how to analyze simulation trajectories to decompose conformation-specific, parameter free, thermodynamically defined protein volumes into residue-based contributions. The total volumes are obtained using established methods from Fluctuation Solution Theory, while the volume decomposition is new and is performed using a simple proximity method. Native and fully extended ubiquitin are used as the test conformations. Changes in the protein volumes are then followed as a function of pressure, allowing for conformation-specific protein compressibility values to also be obtained. Residue volume and compressibility values indicate significant contributions to protein denaturation thermodynamics from nonpolar and coil residues, together with a general negative compressibility exhibited by acidic residues. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole

    International Nuclear Information System (INIS)

    Myung, Yun Soo

    2008-01-01

    We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization

  3. In situ synchrotron radiation X-ray diffraction studies on molecular aggregation structure of nylon 12 films during bulge testing.

    Science.gov (United States)

    Kojio, Ken; Nagano, Chigusa; Fujimoto, Aya; Nozaki, Shuhei; Yokomachi, Kazutoshi; Kamitani, Kazutaka; Watanabe, Hirohmi; Takahara, Atsushi

    2018-02-28

    It is desirable to establish a method for evaluating mechanical properties, such as modulus and strength, of micrometer and sub-micrometer thick polymer films. Bulge tests, where bulge deformation is imposed on films by the pressure of an inert gas, are suitable for satisfying this demand. However, very few studies on polymer films exist in the literature. In this study, bulge testing equipment for in situ synchrotron radiation wide-angle X-ray diffraction (WAXD) measurements is designed and used to study the relationship between the molecular aggregation structure and the mechanical properties of a crystalline nylon 12 (Ny12) film during bulge testing. Isothermally crystallized and quenched Ny12 films exhibited stress-strain curves similar to those obtained by conventional uniaxial elongation. In situ WAXD measurements during bulge testing revealed that the lattice extension of the crystallites is clearly dependent on crystallinity. Concretely, crystallites in the isothermally crystallized film show higher elastic properties than those in the quenched one. The results of the molecular aggregation structure, including the crystal structure and the amorphous chain surrounding the crystallites, of the films during bulge deformation firstly obtained in this study must be useful for designing toughened polymer films.

  4. Thermodynamics of firms' growth

    Science.gov (United States)

    Zambrano, Eduardo; Hernando, Alberto; Hernando, Ricardo; Plastino, Angelo

    2015-01-01

    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1 155 142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of economic system for creating/destroying firms, and that can be used to measure the health of a capitalist-based economy. Indeed, our model predicts that when the exponent is larger than 1, creation of firms is favoured; when it is smaller than 1, destruction of firms is favoured instead; and when it equals 1 (matching Zipf's law), the system is in a full macroeconomic equilibrium, entailing ‘free’ creation and/or destruction of firms. For medium and smaller firm sizes, the dynamical regime changes, the whole distribution can no longer be fitted to a single simple analytical form and numerical prediction is required. Our model constitutes the basis for a full predictive framework regarding the economic evolution of an ensemble of firms. Such a structure can be potentially used to develop simulations and test hypothetical scenarios, such as economic crisis or the response to specific policy measures. PMID:26510828

  5. Physicochemical attack against solid tumors based on the reversal of direction of entropy flow: an attempt to introduce thermodynamics in anticancer therapy

    Directory of Open Access Journals (Sweden)

    Lv Xiaogui

    2006-11-01

    Full Text Available Abstract Background There are many differences between healthy tissue and growing tumor tissue, including metabolic, structural and thermodynamic differences. Both structural and thermodynamic differences can be used to follow the entropy differences in cancerous and normal tissue. Entropy production is a bilinear form of the rates of irreversible processes and the corresponding "generalized forces". Entropy production due to various dissipation mechanisms based on temperature differences, chemical potential gradient, chemical affinity, viscous stress and exerted force is a promising tool for calculations relating to potential targets for tumor isolation and demarcation. Methods The relative importance of five forms of entropy production was assessed through mathematical estimation. Using our mathematical model we demonstrated that the rate of entropy production by a cancerous cell is always higher than that of a healthy cell apart from the case of the application of external energy. Different rates of entropy production by two kinds of cells influence the direction of entropy flow between the cells. Entropy flow from a cancerous cell to a healthy cell transfers information regarding the cancerous cell and propagates its invasive action to the healthy tissues. To change the direction of entropy flow, in addition to designing certain biochemical pathways to reduce the rate of entropy production by cancerous cells, we suggest supplying external energy to the tumor area, changing the relative rate of entropy production by the two kinds of cells and leading to a higher entropy accumulation in the surrounding normal cells than in the tumorous cells. Conclusion Through the use of mathematical models it was quantitatively demonstrated that when no external force field is applied, the rate of entropy production of cancerous cells is always higher than that of healthy cells. However, when the external energy of square wave electric pulses is applied to

  6. Calibrating a large slab vessel: A battle of the bulge

    International Nuclear Information System (INIS)

    Thomas, I.R.

    1993-01-01

    Slab tanks (critically-safe-by-geometry vessels) were proposed for the storage of concentrated, highly-enriched uranium solution in the design of the Fuel Processing Restoration (FPR) Facility at the Idaho Chemical Processing Plant (ICPP). Currently, measurements of bulk mass in ICPP annular vessels have standard deviations on the order of 0.2%, or less. ICPP personnel felt that their inexperience with the aforementioned expansions would prevent them from attaining comparable precision with slab tanks. To help assess the measurement accuracy of slab vessels, a full-scale mockup of those proposed for the FPR Facility was installed for test calibrations. These calibrations were designed to detect vessel expansion under differing conditions. This paper will compare the base-line, water calibrations with those of the higher-density aluminum nitrate, and any observed deflection will be described using vessel calibration techniques. The calibration using water at an elevated temperature was not performed due to the difficulty of maintaining the elevated temperature. This calibration probably will not be conducted because the construction of the FPR Facility has been halted

  7. Statistical thermodynamics of alloys

    CERN Document Server

    Gokcen, N A

    1986-01-01

    This book is intended for scientists, researchers, and graduate students interested in solutions in general, and solutions of metals in particular. Readers are assumed to have a good background in thermodynamics, presented in such books as those cited at the end of Chapter 1, "Thermo­ dynamic Background." The contents of the book are limited to the solutions of metals + metals, and metals + metalloids, but the results are also appli­ cable to numerous other types of solutions encountered by metallurgists, materials scientists, geologists, ceramists, and chemists. Attempts have been made to cover each topic in depth with numerical examples whenever necessary. Chapter 2 presents phase equilibria and phase diagrams as related to the thermodynamics of solutions. The emphasis is on the binary diagrams since the ternary diagrams can be understood in terms of the binary diagrams coupled with the phase rule, and the Gibbs energies of mixing. The cal­ culation of thermodynamic properties from the phase diagrams is ...

  8. Thermodynamics of Crystalline States

    CERN Document Server

    Fujimoto, Minoru

    2010-01-01

    Thermodynamics is a well-established discipline of physics for properties of matter in thermal equilibrium surroundings. Applying to crystals, however, the laws encounter undefined properties of crystal lattices, which therefore need to be determined for a clear and well-defined description of crystalline states. Thermodynamics of Crystalline States explores the roles played by order variables and dynamic lattices in crystals in a wholly new way. This book is divided into three parts. The book begins by clarifying basic concepts for stable crystals. Next, binary phase transitions are discussed to study collective motion of order variables, as described mostly as classical phenomena. In the third part, the multi-electron system is discussed theoretically, as a quantum-mechanical example, for the superconducting state in metallic crystals. Throughout the book, the role played by the lattice is emphasized and examined in-depth. Thermodynamics of Crystalline States is an introductory treatise and textbook on meso...

  9. Extended Irreversible Thermodynamics

    CERN Document Server

    Jou, David

    2010-01-01

    This is the 4th edition of the highly acclaimed monograph on Extended Irreversible Thermodynamics, a theory that goes beyond the classical theory of irreversible processes. In contrast to the classical approach, the basic variables describing the system are complemented by non-equilibrium quantities. The claims made for extended thermodynamics are confirmed by the kinetic theory of gases and statistical mechanics. The book covers a wide spectrum of applications, and also contains a thorough discussion of the foundations and the scope of the current theories on non-equilibrium thermodynamics. For this new edition, the authors critically revised existing material while taking into account the most recent developments in fast moving fields such as heat transport in micro- and nanosystems or fast solidification fronts in materials sciences. Several fundamental chapters have been revisited emphasizing physics and applications over mathematical derivations. Also, fundamental questions on the definition of non-equil...

  10. Thermodynamics of complexity

    DEFF Research Database (Denmark)

    Westerhoff, Hans V.; Jensen, Peter Ruhdal; Snoep, Jacky L.

    1998-01-01

    the thesis that the aforesaid holds a fortiori for the living cell: Much of the essence of the live state depends more on the manner in which the molecules are organised than on the properties of single molecules. This is due to the phenomenon of 'Complexity'. BioComplexity is defined here as the phenomenon...... understanding of this BioComplexity, modem thermodynamic concepts and methods (nonequilibrium thermodynamics, metabolic and hierarchical control analysis) will be needed. We shall propose to redefine nonequilibrium thermodynamics as: The science that aims at understanding the behaviour of nonequilibrium systems...... with metabolic control analysis. Subsequently, the complexity of the control of the energy metabolism of E. coli will be analysed in detail. New control theorems will be derived for newly defined control coefficients. It will become transparent that molecular genetic experimentation will allow one to penetrate...

  11. Development of Bi-base high-temperature Pb-free solders with second-phase dispersion: Thermodynamic calculation, microstructure, and interfacial reaction

    Science.gov (United States)

    Takaku, Yoshikazu; Ohnuma, Ikuo; Kainuma, Ryosuke; Yamada, Yasushi; Yagi, Yuji; Nishibe, Yuji; Ishida, Kiyohito

    2006-11-01

    Bismuth and its alloys are candidates for Pb-free high-temperature solders that can be substituted for conventional Pb-rich Pb-Sn solders (melting point (mp) = 573 583 K). However, inferior properties such as brittleness and weak bonding strength should be improved for practical use. To that end, BiCu-X (X=Sb, Sn, and Zn) Pb-free high-temperature solders are proposed. Miscibility gaps in liquid BiCu-X alloys were surveyed using the thermodynamic database ADAMIS (alloy database for micro-solders), and compositions of the BiCu-X solders were designed on the basis of calculation. In-situ composite solders that consist of a Bi-base matrix with fine intermetallic compound (IMC) particles were produced by gas-atomizing and melt-spinning methods. The interfacial reaction between in-situ composite solders and Cu or Ni substrates was investigated. The IMCs at the interface formed a thin, uniform layer, which is an appropriate morphology for a reliable solder joint.

  12. Development of a modelling process for the Otto-DI combustion process based on thermodynamics; Erarbeitung eines thermodynamisch basierten Modellierungsverfahrens fuer den Otto-DI Verbrennungsprozess

    Energy Technology Data Exchange (ETDEWEB)

    Koch, T.; Schaenzlin, K.; Boulouchos, K.

    2004-07-01

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project carried out at the Federal Institute of Technology in Zurich, Switzerland, to develop a thermodynamics-based modelling process for the Otto-DI (direct injection) combustion process. As part of the development of the 'Codino' twin-zone model, the aim of this project was to provide an experimentally sound and convincing basis for the work. Several measurement techniques used on the institute's single-cylinder research engine are discussed, including ion-flow, endoscopy, the two-colour method, spectrography and the use of an optical fibre probe and emission-measurements in the exhaust gasses. Simulations made in parallel with the experiments are also discussed. The results obtained using this measurement-technology 'pool' are presented, whereby an accent is set on the physical-chemical processes involved from the start of mixture preparation up to the end of the combustion process.

  13. Mechanics, Waves and Thermodynamics

    Science.gov (United States)

    Ranjan Jain, Sudhir

    2016-05-01

    Figures; Preface; Acknowledgement; 1. Energy, mass, momentum; 2. Kinematics, Newton's laws of motion; 3. Circular motion; 4. The principle of least action; 5. Work and energy; 6. Mechanics of a system of particles; 7. Friction; 8. Impulse and collisions; 9. Central forces; 10. Dimensional analysis; 11. Oscillations; 12. Waves; 13. Sound of music; 14. Fluid mechanics; 15. Water waves; 16. The kinetic theory of gases; 17. Concepts and laws of thermodynamics; 18. Some applications of thermodynamics; 19. Basic ideas of statistical mechanics; Bibliography; Index.

  14. Thermodynamics for engineers

    CERN Document Server

    Wong, Kaufui Vincent

    2011-01-01

    Praise for the First Edition from Students: "It is a great thermodynamics text…I loved it!-Mathew Walters "The book is comprehensive and easy to understand. I love the real world examples and problems, they make you feel like you are learning something very practical."-Craig Paxton"I would recommend the book to friends."-Faure J. Malo-Molina"The clear diction, as well as informative illustrations and diagrams, help convey the material clearly to the reader."-Paul C. Start"An inspiring and effective tool for any aspiring scientist or engineer. Definitely the best book on Classical Thermodynamics out."-Seth Marini.

  15. Concise chemical thermodynamics

    CERN Document Server

    Peters, APH

    2010-01-01

    EnergyThe Realm of ThermodynamicsEnergy BookkeepingNature's Driving ForcesSetting the Scene: Basic IdeasSystem and SurroundingsFunctions of StateMechanical Work and Expanding GasesThe Absolute Temperature Scale Forms of Energy and Their Interconversion Forms of Renewable Energy Solar Energy Wind Energy Hydroelectric Power Geothermal Energy Biomass Energy References ProblemsThe First Law of Thermodynamics Statement of the First Law Reversible Expansion of an Ideal GasConstant-Volume ProcessesConstant-Pressure ProcessesA New Function: EnthalpyRelationship between ?H and ?UUses and Conventions of

  16. Thermodynamics of ABC transporters

    Directory of Open Access Journals (Sweden)

    Xuejun C. Zhang

    2015-09-01

    Full Text Available ABSTRACT ABC transporters form the largest of all transporter families, and their structural study has made tremendous progress over recent years. However, despite such advances, the precise mechanisms that determine the energy-coupling between ATP hydrolysis and the conformational changes following substrate binding remain to be elucidated. Here, we present our thermodynamic analysis for both ABC importers and exporters, and introduce the two new concepts of differential-binding energy and elastic conformational energy into the discussion. We hope that the structural analysis of ABC transporters will henceforth take thermodynamic aspects of transport mechanisms into account as well.

  17. Thermodynamics II essentials

    CERN Document Server

    REA, The Editors of

    2013-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Thermodynamics II includes review of thermodynamic relations, power and refrigeration cycles, mixtures and solutions, chemical reactions, chemical equilibrium, and flow through nozzl

  18. Looking for a Rational Thermodynamics in the late XIX century

    OpenAIRE

    Bordoni, S.

    2013-01-01

    From Rudolf Clausius’ classical version of Thermodynamics two different traditions of research really emerged. If James C. Maxwell and Ludwig Boltzmann pursued the integration of thermodynamics with the kinetic theory of gases, others relied on a macroscopic and more abstract approach, which set aside specific mechanical models. Starting from 1869, the French engineer François Massieu was able to demonstrate that thermodynamics could be based on two “characteristic functions” or potentials. J...

  19. Study of the coupling of geochemical models based on thermodynamic equilibrium with models of component transfer as solutions in porous media or fractures

    International Nuclear Information System (INIS)

    Coudrain-Ribstein, A.

    1985-01-01

    This study is a contribution of analyses possibilities of modelling the transfer of components in the underground taking into account complexes geochemical phenomena. In the first part, the aim and the methodology of existing codes are presented. The transfer codes describe with a great precision the physical phenomena of transport but they are based on a very simple conceptualisation of the geochemical phenomena of retention by the rock. The geochemical models are interested by a stable unity of volume. They allow to compute the equilibrium distribution of the components between the chemical species of the solution, and the solid and gaseous phases. They use important thermodynamic data bases corresponding to each possible reaction. To sum up the situation about the geochemical codes in Europe and United States, a list of about thirty codes describe their method and potentialities. The mathematical analysis of the different methods used in both types of codes is presented. Then, the principles of a modelisation associating the potentialities of the transport codes and the geochemical codes are discussed. It is not possible to think of a simple coupling. A general code must be established on the bases of the existing codes but also on new concepts and under new constraints. In such studies one must always deal with the problem of the reactions kinetics. When the velocity of the reactions is big enough versus the velocity of transport processes, the assumption of local geochemical equilibrium can be retained. A general code would be very cumbersome, expensive and difficult to use. The results would be difficult to analyse and exploit. On the other hand, for each case study, a detailed analysis can point out many computing simplifications without simplifying the concepts [fr

  20. A parametric description of the 3D structure of the Galactic bar/bulge using the VVV survey

    Science.gov (United States)

    Simion, I. T.; Belokurov, V.; Irwin, M.; Koposov, S. E.; Gonzalez-Fernandez, C.; Robin, A. C.; Shen, J.; Li, Z.-Y.

    2017-11-01

    We study the structure of the inner Milky Way using the latest data release of the VISTA Variables in the Via Lactea (VVV) survey. The VVV is a deep near-infrared, multi-colour photometric survey with a coverage of 300 square degrees towards the bulge/bar. We use red clump (RC) stars to produce a high-resolution dust map of the VVV's field of view. From de-reddened colour-magnitude diagrams, we select red giant branch stars to investigate their 3D density distribution within the central 4 kpc. We demonstrate that our best-fitting parametric model of the bulge density provides a good description of the VVV data, with a median percentage residual of 5 per cent over the fitted region. The strongest of the otherwise low-level residuals are overdensities associated with a low-latitude structure as well as the so-called X-shape previously identified using the split RC. These additional components contribute only ˜5 per cent and ˜7 per cent respectively to the bulge mass budget. The best-fitting bulge is `boxy' with an axial ratio of [1:0.44:0.31] and is rotated with respect to the Sun-Galactic Centre line by at least 20°. We provide an estimate of the total, full sky, mass of the bulge of M_bulge^{Chabrier} = 2.36 × 10^{10} M_{⊙} for a Chabrier initial mass function. We show that there exists a strong degeneracy between the viewing angle and the dispersion of the RC absolute magnitude distribution. The value of the latter is strongly dependent on the assumptions made about the intrinsic luminosity function of the bulge.

  1. Experimental thermodynamics experimental thermodynamics of non-reacting fluids

    CERN Document Server

    Neindre, B Le

    2013-01-01

    Experimental Thermodynamics, Volume II: Experimental Thermodynamics of Non-reacting Fluids focuses on experimental methods and procedures in the study of thermophysical properties of fluids. The selection first offers information on methods used in measuring thermodynamic properties and tests, including physical quantities and symbols for physical quantities, thermodynamic definitions, and definition of activities and related quantities. The text also describes reference materials for thermometric fixed points, temperature measurement under pressures, and pressure measurements. The publicatio

  2. Black Hole Thermodynamics in an Undergraduate Thermodynamics Course.

    Science.gov (United States)

    Parker, Barry R.; McLeod, Robert J.

    1980-01-01

    An analogy, which has been drawn between black hole physics and thermodynamics, is mathematically broadened in this article. Equations similar to the standard partial differential relations of thermodynamics are found for black holes. The results can be used to supplement an undergraduate thermodynamics course. (Author/SK)

  3. Correct thermodynamic forces in Tsallis thermodynamics: connection with Hill nanothermodynamics

    International Nuclear Information System (INIS)

    Garcia-Morales, Vladimir; Cervera, Javier; Pellicer, Julio

    2005-01-01

    The equivalence between Tsallis thermodynamics and Hill's nanothermodynamics is established. The correct thermodynamic forces in Tsallis thermodynamics are pointed out. Through this connection we also find a general expression for the entropic index q which we illustrate with two physical examples, allowing in both cases to relate q to the underlying dynamics of the Hamiltonian systems

  4. Eyes - bulging

    Science.gov (United States)

    ... lamp examination may be done. Blood testing for thyroid disease may be done. Treatments depend on the cause. ... team. Eye Diseases Read more Hyperthyroidism Read more Thyroid Diseases Read more A.D.A.M., Inc. is ...

  5. Fontanelles - bulging

    Science.gov (United States)

    ... JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 88. Review Date 2/16/2017 Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, ...

  6. Exploring the Chemical Composition and Double Horizontal Branch of the Bulge Globular Cluster NGC 6569

    Science.gov (United States)

    Johnson, Christian I.; Rich, R. Michael; Caldwell, Nelson; Mateo, Mario; Bailey, John I., III; Olszewski, Edward W.; Walker, Matthew G.

    2018-02-01

    Photometric and spectroscopic analyses have shown that the Galactic bulge cluster Terzan 5 hosts several populations with different metallicities and ages that manifest as a double red horizontal branch (HB). A recent investigation of the massive bulge cluster NGC 6569 revealed a similar, though less extended, HB luminosity split, but little is known about the cluster’s detailed chemical composition. Therefore, we have used high-resolution spectra from the Magellan–M2FS and VLT–FLAMES spectrographs to investigate the chemical compositions and radial velocity distributions of red giant branch and HB stars in NGC 6569. We found the cluster to have a mean heliocentric radial velocity of ‑48.8 km s‑1 (σ = 5.3 km s‑1 148 stars) and =-0.87 dex (19 stars), but the cluster’s 0.05 dex [Fe/H] dispersion precludes a significant metallicity spread. NGC 6569 exhibits light- and heavy-element distributions that are common among old bulge/inner Galaxy globular clusters, including clear (anti)correlations between [O/Fe], [Na/Fe], and [Al/Fe]. The light-element data suggest that NGC 6569 may be composed of at least two distinct populations, and the cluster’s low =-0.11 dex indicates significant pollution with r-process material. We confirm that both HBs contain cluster members, but metallicity and light-element variations are largely ruled out as sources for the luminosity difference. However, He mass fraction differences as small as ΔY ∼ 0.02 cannot be ruled out and may be sufficient to reproduce the double HB.

  7. Batch kinetics, isotherm and thermodynamic studies of adsorption of strontium from aqueous solutions onto low cost rice-straw based carbons.

    Directory of Open Access Journals (Sweden)

    S. M. Yakout

    2010-09-01

    Full Text Available Present study explored the feasibility of using waste rice-straw based carbons as adsorbent for the removal of strontium under different experimental conditions. The batch sorption is studied with respect to solute concentration (2.8 - 110 mg/L, contact time, adsorbent dose (2.5 - 20 g/L and solution temperature (25 - 55oC. The Langmuir and Dubinin-Radushkevich adsorption models were applied to experimental equilibrium data and isotherm constants were calculated using linear regression analysis. A comparison of kinetic models applied to the adsorption of strontium on rice-straw carbon was evaluated for the pseudo-second-order, Elovich, intraparticle diffusion and Bangham’s kinetics models. The experimental data fitted very well the pseudosecond-order kinetic model and also followed by intra-particle diffusion model, whereas diffusion is not only the rate-controlling step. The results show that the sorption capacity increases with an increase in solution temperature from 25 to 55 oC. The thermodynamics parameters were evaluated. The positive value of ΔH (40.93 kJ indicated that the adsorption of strontium onto RS1 carbon was endothermic, which result was supported by the increasing adsorption of strontium with temperature. The positive value of ΔS (121.8 kJ/mol reflects good affinity of strontium ions towards the rice-straw based carbons. The results have establishedgood potentiality for the carbons particles to be used as a sorbent for the removal of strontium from wastewater.

  8. Thermodynamics and statistical mechanics

    CERN Document Server

    Landsberg, Peter T

    1990-01-01

    Exceptionally articulate treatment combines precise mathematical style with strong physical intuition. Wide range of applications includes negative temperatures, negative heat capacities, special and general relativistic effects, black hole thermodynamics, gravitational collapse, more. Over 100 problems with worked solutions. Advanced undergraduate, graduate level. Table of applications. Useful formulas and other data.

  9. Thermodynamics applied. Where? Why?

    NARCIS (Netherlands)

    Hirs, Gerard

    2003-01-01

    In recent years, thermodynamics has been applied in a number of new fields leading to a greater societal impact. This paper gives a survey of these new fields and the reasons why these applications are important. In addition, it is shown that the number of fields could be even greater in the future

  10. On Teaching Thermodynamics

    Science.gov (United States)

    Debbasch, F.

    2011-01-01

    The logical structure of classical thermodynamics is presented in a modern, geometrical manner. The first and second law receive clear, operatively oriented statements and the Gibbs free energy extremum principle is fully discussed. Applications relevant to chemistry, such as phase transitions, dilute solutions theory and, in particular, the law…

  11. Thermodynamics, applied. : Where? why?

    NARCIS (Netherlands)

    Hirs, Gerard

    1999-01-01

    In recent years thermodynamics has been applied in a number of new fields leading to a greater societal impact. The paper gives a survey of these new fields and the reasons why these applications are important. In addition it is shown that the number of fields could be even greater in the future and

  12. Thermodynamical Arguments against Evolution

    Science.gov (United States)

    Rosenhouse, Jason

    2017-01-01

    The argument that the second law of thermodynamics contradicts the theory of evolution has recently been revived by anti-evolutionists. In its basic form, the argument asserts that whereas evolution implies that there has been an increase in biological complexity over time, the second law, a fundamental principle of physics, shows this to be…

  13. Thermodynamics of meat proteins

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2012-01-01

    We describe the water activity of meat, being a mixture of proteins, salts and water, by the Free-Volume-Flory–Huggins (FVFH) theory augmented with the equation. Earlier, the FVFH theory is successfully applied to describe the thermodynamics to glucose homopolymers like starch, dextrans and

  14. New perspectives in thermodynamics

    International Nuclear Information System (INIS)

    Serrin, J.

    1986-01-01

    The last decade has seen a unity of method and approach in the foundations of thermodynamics and continuum mechanics, in which rigorous laws of thermodynamics have been combined with invariance notions of mechanics to produce new and deep understanding. Real progress has been made in finding a set of appropriate concepts for classical thermodynamics, by which energy conservation and the Clausius inequality can be given well-defined meanings for arbitrary processes and which allow an approach to the entropy concept which is free of traditional ambiguities. There has been, moreover, a careful scrutiny of long established but nevertheless not sharply defined concepts such as the Maxwell equal-area rule, the famous Gibbs phase rule, and the equivalence of work and heat. The thirteen papers in this volume accordingly gather together for the first time the many ideas and concepts which have raised classical thermodynamics from a heuristic and intuitive science to the level of precision presently demanded of other branches of mathematical physics

  15. Thermodynamics Far from the Thermodynamic Limit.

    Science.gov (United States)

    de Miguel, Rodrigo; Rubí, J Miguel

    2017-11-16

    Understanding how small systems exchange energy with a heat bath is important to describe how their unique properties can be affected by the environment. In this contribution, we apply Landsberg's theory of temperature-dependent energy levels to describe the progressive thermalization of small systems as their spectrum is perturbed by a heat bath. We propose a mechanism whereby the small system undergoes a discrete series of excitations and isentropic spectrum adjustments leading to a final state of thermal equilibrium. This produces standard thermodynamic results without invoking system size. The thermal relaxation of a single harmonic oscillator is analyzed as a model example of a system with a quantized spectrum than can be embedded in a thermal environment. A description of how the thermal environment affects the spectrum of a small system can be the first step in using environmental factors, such as temperature, as parameters in the design and operation of nanosystem properties.

  16. Thermodynamic analysis of water vapor sorption isotherms and mechanical properties of selected paper-based food packaging materials.

    Science.gov (United States)

    Rhim, Jong-Whan; Lee, Jun Ho

    2009-01-01

    Adsorption isotherms of 3 selected paper-based packaging materials, that is, vegetable parchment (VP) paper, Kraft paper, and solid-bleached-sulfate (SBS) paperboard, were determined at 3 different temperatures (25, 40, and 50 degrees C). The GAB isotherm model was found to fit adequately for describing experimental adsorption isotherm data for the paper samples. The monolayer moisture content of the paper samples decreased with increase in temperature, which is in the range of 0.0345 to 0.0246, 0.0301 to 0.0238, and 0.0318 to 0.0243 g water/g solid for the MG paper, the Kraft paper, and the SBS paperboard, respectively. The net isosteric heats of sorption (q(st)) for the paper samples decreased exponentially with increase in moisture content after reaching the maximum values of 18.51, 27.39, and 26.80 kJ/mol for the VP paper, the Kraft paper, and the SBS paperboard, respectively, at low-moisture content. The differential enthalpy and entropy of 3 paper samples showed compensation phenomenon with the isokinetic temperature of 399.7 K indicating that water vapor had been adsorbed onto the paper samples with the same mechanism. Depending on the paper material, tensile strength of paper samples was affected by moisture content.

  17. JAEA thermodynamic database for performance assessment of geological disposal of high-level and TRU wastes. Selection of thermodynamic data of cobalt and nickel

    International Nuclear Information System (INIS)

    Kitamura, Akira; Yui, Mikazu; Kirishima, Akira; Saito, Takumi; Shibutani, Sanae; Tochiyama, Osamu

    2009-11-01

    Within the scope of the JAEA thermodynamic database project for performance assessment of geological disposal of high-level and TRU wastes, the selection of the thermodynamic data on the inorganic compounds and complexes of cobalt and nickel have been carried out. For cobalt, extensive literature survey has been performed and all the obtained literatures have been carefully reviewed to select the thermodynamic data. Selection of thermodynamic data of nickel has been based on a thermodynamic database published by the Nuclear Energy Agency in the Organisation for Economic Co-operation and Development (OECD/NEA), which has been carefully reviewed by the authors, and then thermodynamic data have been selected after surveying latest literatures. Based on the similarity of chemical properties between cobalt and nickel, complementary thermodynamic data of nickel and cobalt species expected under the geological disposal condition have been selected to complete the thermodynamic data set for the performance assessment of geological disposal of radioactive wastes. (author)

  18. The SWELLS survey - VI. Hierarchical inference of the initial mass functions of bulges and discs

    DEFF Research Database (Denmark)

    Brewer, Brendon J.; Marshal, Philip J.; Auger, Matthew W.

    2014-01-01

    ) and stellar masses (constrained by optical and near-infrared colours in the context of a stellar population synthesis model, up to an IMF normalization parameter). Using minimal assumptions apart from the physical constraint that the total stellar mass m* within any aperture must be less than the total mass...... information about multiple astronomical objects. This modelling approach allows us to place upper limits on the size of any departures from universality. More data, including spatially resolved kinematics (as in Paper V) and stellar population diagnostics over a range of bulge and disc masses, are needed...

  19. Bulge formed cooling channels with a variable lead helix on a hollow body of revolution

    Science.gov (United States)

    McAninch, Michael D. (Inventor); Holbrook, Richard L. (Inventor); Lacount, Dale F. (Inventor); Kawashige, Chester M. (Inventor); Crapuchettes, John M. (Inventor); Scala, James (Inventor)

    1993-01-01

    A method of constructing a nozzle having cooling channels comprises a shell and a liner which are formed into a body of revolution having an axis of revolution. Helical welds are formed to hold the liner and shell to each other with a channel position being defined between each pair of helical welds. Pressurized fluid which may be a gas or a liquid, is introduced between the weld pairs to outwardly bulge the material of at least one of the liner and shell to define the channels.

  20. Thermodynamics for the practicing engineer

    CERN Document Server

    Theodore, Louis; Vanvliet, Timothy

    2009-01-01

    This book concentrates specifically on the applications of thermodynamics, rather than the theory. It addresses both technical and pragmatic problems in the field, and covers such topics as enthalpy effects, equilibrium thermodynamics, non-ideal thermodynamics and energy conversion applications. Providing the reader with a working knowledge of the principles of thermodynamics, as well as experience in their application, it stands alone as an easy-to-follow self-teaching aid to practical applications and contains worked examples.

  1. Thermodynamic geometry and the metrics of Weinhold and Gilmore

    International Nuclear Information System (INIS)

    Andresen, B.; Berry, R.S.; Gilmore, R.; Ihrig, E.; Salamon, P.

    1987-01-01

    The thermodynamic geometries of Gibbs, Weinhold, and Gilmore are compared and the benefits of each are pointed out along with the structures which must be abandoned in order to reap the benefits. When Weinhold's metric is used to measure distance in the equation of state surface, the traditional Gibbsian picture of equilibrium thermodynamics, based on convexity, must be abandoned. Gilmore's metric is compatible with standard Gibbsian thermodynamics. This metric measures distance in the potential surface of statistical mechanics rather than the equation of state surface of equilibrium thermodynamics. (orig.)

  2. Thermodynamic modeling of the Co-Fe-O system

    DEFF Research Database (Denmark)

    Zhang, Weiwei; Chen, Ming

    2013-01-01

    As a part of the research project aimed at developing a thermodynamic database of the La-Sr-Co-Fe-O system for applications in Solid Oxide Fuel Cells (SOFCs), the Co-Fe-O subsystem was thermodynamically re-modeled in the present work using the CALPHAD methodology. The solid phases were described...... using the Compound Energy Formalism (CEF) and the ionized liquid was modeled with the ionic two-sublattice model based on CEF. A set of self-consistent thermodynamic parameters was obtained eventually. Calculated phase diagrams and thermodynamic properties are presented and compared with experimental...

  3. Thermodynamic analysis of a novel multigeneration energy system based on heat recovery from a biomass CHP cycle

    International Nuclear Information System (INIS)

    Soltani, Reza; Dincer, Ibrahim; Rosen, Marc A.

    2015-01-01

    A multigeneration energy system with one fuel intake (sawdust biomass fuel) and five useful outputs is proposed and energy and exergy analyses are carried out to assess its performance. Instead of using a simple heat exchanger to satisfy district heating needs, applying a deaerator is found to result in 10% more hot water mass flow rate for the same conditions. The energy and exergy efficiencies of the multigeneration system are found to be around 60% and 25%, respectively, while the corresponding energy and exergy efficiencies of a biomass system with only electricity generation are 11% and 13%, respectively. When investigating the effect of adding various product outputs to biomass power generation, steam generation and then domestic hot water production are found to have the greatest enhancing effects on the system efficiencies. Heat recovery from exhaust gases for district heating and wood drying is found to enhance the energy efficiency more than the exergy efficiency. Also, due to the size of the heat recovery system, which is smaller than the biomass CHP cycle, district heating and drying cannot increase the energy and exergy efficiencies of the primary system like steam generation. A parametric study shows that the biomass fuel input rate affects significantly the district heating heat load and the electricity generation rate, in a linear manner. However, increasing the biomass input rate has no effect on the CHP system energy and exergy efficiencies, while increasing the exergy efficiency of the entire system and decreasing its corresponding energy efficiency slightly. Of the several heat recovery options from exhaust gases, electricity generation and wood drying result in the highest exergy efficiency while district heating and drying lead to highest energy efficiency. - Highlights: • Novel heat recovery based energy system is proposed. • There is one energy input while system has 5 useful outputs. • Combustion excess air increases district heating

  4. Thermodynamics of High Temperature Plasmas

    Directory of Open Access Journals (Sweden)

    Ettore Minardi

    2009-03-01

    Full Text Available In this work we discuss how and to what extent the thermodynamic concepts and the thermodynamic formalism can be extended to the description of high temperature states of the plasma not necessarily associated with a Boltzmann distribution and with thermal equilibrium.The discussion is based on the “magnetic or electrostatic entropy concept”, an interpretative and predictive tool based on probability and information, defined in a suitably coarse-grained possibility space of all current density or of all electric charge density distributions under testable constraints, and whose variation properties are proven to be related under certain conditions to the equilibrium and the stability of the system. In the case of magnetic equilibrium the potentiality of the magnetic entropy concept is illustrated by comparing the predictions of the current density and pressure profiles with the observations in different tokamak machines and different tokamak regimes, as well as by showing how the equilibrium and the stability in devices as different as the reversed field pinch or the magnetic well are described by the variation properties of the same entropy functional applied to the different situations. In fact it emerges that the maximum of the entropy can be seen in these different cases as an optimization constraint for the minimum of the magnetic energy. The application of the entropy concept to the electrostatic processes shows in particular that the so-called reactive instabilities (non-dissipative, non-resonant instabilities with a marginal point admit a neighboring state with higher entropy and are therefore of special relevance from the point of view of the physical evolution of the system. In this case the thermodynamic formalism allows the introduction of the concept of “thermodynamic fluctuations” of the macroscopic charge density and provides a method for the calculation of the “thermodynamic” fluctuation levels both on the stable as

  5. Choice of the thermodynamic variables

    International Nuclear Information System (INIS)

    Balian, R.

    1985-09-01

    Some basic ideas of thermodynamics and statistical mechanics, both at equilibrium and off equilibrium, are recalled. In particular, the selection of relevant variables which underlies any macroscopic description is discussed, together with the meaning of the various thermodynamic quantities, in order to set the thermodynamic approaches used in nuclear physics in a general prospect [fr

  6. Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way

    Science.gov (United States)

    Bensby, T.; Feltzing, S.; Gould, A.; Yee, J. C.; Johnson, J. A.; Asplund, M.; Meléndez, J.; Lucatello, S.; Howes, L. M.; McWilliam, A.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Pietrukowicz, P.; Skowron, J.; Mróz, P.; Pawlak, M.; Abe, F.; Asakura, Y.; Bhattacharya, A.; Bond, I. A.; Bennett, D. P.; Hirao, Y.; Nagakane, M.; Koshimoto, N.; Sumi, T.; Suzuki, D.; Tristram, P. J.

    2017-09-01

    We present a detailed elemental abundance study of 90 F and G dwarf, turn-off, and subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages and abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y and Ba) have been determined. Four main findings are presented: (1) a wide metallicity distribution with distinct peaks at [Fe/H] = -1.09, -0.63, -0.20, + 0.12, + 0.41; (2) ahigh fraction of intermediate-age to young stars where at [Fe/H] > 0 more than 35% are younger than 8 Gyr, and for [Fe/H] ≲ -0.5 most stars are 10 Gyr or older; (3) several episodes of significant star formation in the bulge has been identified: 3, 6, 8, and 11 Gyr ago; (4) tentatively the "knee" in the α-element abundance trends of the sub-solar metallicity bulge is located at a slightly higher [Fe/H] than in the local thick disk. These findings show that the Galactic bulge has complex age and abundance properties that appear to be tightly connected to the main Galactic stellar populations. In particular, the peaks in the metallicity distribution, the star formation episodes, and the abundance trends, show similarities with the properties of the Galactic thin and thick disks. At the same time, the star formation rate appears to have been slightly faster in the bulge than in the local thick disk, which most likely is an indication of the denser stellar environment closer to the Galactic centre. There are also additional components not seen outside the bulge region, and that most likely can be associated with the Galactic bar. Our results strengthen the observational evidence that support the idea of a secular origin for the Galactic bulge, formed out of the other main Galactic stellar populations present in the central regions of our Galaxy. Additionally, our analysis of this enlarged sample suggests that the (V-I)0 colour of the bulge red clump should be revised to 1.09. Based on data obtained with the

  7. Comprehensive thermodynamic study of methylprednisolone

    International Nuclear Information System (INIS)

    Knyazev, A.V.; Emel'yanenko, V.N.; Smirnova, N.N.; Zaitsau, D.H.; Stepanova, O.V.; Shipilova, A.S.; Markin, A.V.; Gusarova, E.V.; Knyazeva, S.S.; Verevkin, S.P.

    2017-01-01

    Highlights: • Temperature dependence of heat capacity of methylprednisolone has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the methylprednisolone have been determined for the range from T → 0 to 350 K. • Enthalpy of combustion of the methylprednisolone was measured using high-precision combustion calorimeter. • The standard molar enthalpy of sublimation was measured by using the quartz-crystal microbalance. - Abstract: In the present work the temperature dependence of heat capacity for methylprednisolone has been measured for the first time over the temperature range from 6 to 350 K using by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the methylprednisolone, namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been evaluated from the experimental values for the range from T → 0 to 350 K. Standard molar enthalpy of combustion (−11898.9 ± 6.7) kJ·mol"−"1 of the methylprednisolone was measured for the first time using high-precision combustion calorimeter. The standard molar enthalpy of formation in the crystalline state (−1045.8 ± 7.3) kJ·mol"−"1 of compound at 298.15 K was derived from the combustion experiments. The standard molar enthalpy of sublimation at 298.15 K (194.5 ± 2.2) kJ·mol"−"1 was measured by using the quartz-crystal microbalance (QCM). Using combination of the adiabatic and combustion calorimetry with the result from QCM, the thermodynamic functions of the methylprednisolone at T = 298.15 K and p = 0.1 MPa have been calculated.

  8. Bioengineering thermodynamics of biological cells.

    Science.gov (United States)

    Lucia, Umberto

    2015-12-01

    Cells are open complex thermodynamic systems. They can be also regarded as complex engines that execute a series of chemical reactions. Energy transformations, thermo-electro-chemical processes and transports phenomena can occur across the cells membranes. Moreover, cells can also actively modify their behaviours in relation to changes in their environment. Different thermo-electro-biochemical behaviours occur between health and disease states. But, all the living systems waste heat, which is no more than the result of their internal irreversibility. This heat is dissipated into the environment. But, this wasted heat represent also a sort of information, which outflows from the cell toward its environment, completely accessible to any observer. The analysis of irreversibility related to this wasted heat can represent a new approach to study the behaviour of the cells themselves and to control their behaviours. So, this approach allows us to consider the living systems as black boxes and analyze only the inflows and outflows and their changes in relation to the modification of the environment. Therefore, information on the systems can be obtained by analyzing the changes in the cell heat wasted in relation to external perturbations. The bioengineering thermodynamics bases are summarized and used to analyse possible controls of the calls behaviours based on the control of the ions fluxes across the cells membranes.

  9. On the physical nature of globular cluster candidates in the Milky Way bulge

    Science.gov (United States)

    Piatti, A. E.

    2018-03-01

    We present results from 2MASS JKs photometry on the physical reality of recently reported globular cluster (GC) candidates in the Milky Way (MW) bulge. We relied our analysis on photometric membership probabilities that allowed us to distinguish real stellar aggregates from the composite field star population. When building colour-magnitude diagrams and stellar density maps for stars at different membership probability levels, the genuine GC candidate populations are clearly highlighted. We then used the tip of the red giant branch (RGB) as distance estimator, resulting heliocentric distances that place many of the objects in regions near of the MW bulge where no GC had been previously recognised. Some few GC candidates resulted to be MW halo/disc objects. Metallicities estimated from the standard RGB method are in agreement with the values expected according to the position of the GC candidates in the Galaxy. Finally, we derived from the first time their structural parameters. We found that the studied objects have core, half-light and tidal radii in the ranges spanned by the population of known MW GCs. Their internal dynamical evolutionary stages will be described properly when their masses are estimated.

  10. Dark Atoms and the Positron-Annihilation-Line Excess in the Galactic Bulge

    Directory of Open Access Journals (Sweden)

    J.-R. Cudell

    2014-01-01

    Full Text Available It was recently proposed that stable particles of charge −2, O--, can exist and constitute dark matter after they bind with primordial helium in O-helium (OHe atoms. We study here in detail the possibility that this model provides an explanation for the excess of gamma radiation in the positron-annihilation line from the galactic bulge observed by INTEGRAL. This explanation assumes that OHe, excited to a 2s state through collisions in the central part of the Galaxy, deexcites to its ground state via an E0 transition, emitting an electron-positron pair. The cross-section for OHe collisions with excitation to 2s level is calculated and it is shown that the rate of such excitations in the galactic bulge strongly depends not only on the mass of O-helium, which is determined by the mass of O--, but also on the density and velocity distribution of dark matter. Given the astrophysical uncertainties on these distributions, this mechanism constrains the O-- mass to lie in two possible regions. One of these is reachable in the experimental searches for stable multicharged particles at the LHC.

  11. The Illustris simulation: supermassive black hole-galaxy connection beyond the bulge

    Science.gov (United States)

    Mutlu-Pakdil, Burçin; Seigar, Marc S.; Hewitt, Ian B.; Treuthardt, Patrick; Berrier, Joel C.; Koval, Lauren E.

    2018-02-01

    We study the spiral arm morphology of a sample of the local spiral galaxies in the Illustris simulation and explore the supermassive black hole-galaxy connection beyond the bulge (e.g. spiral arm pitch angle, total stellar mass, dark matter mass, and total halo mass), finding good agreement with other theoretical studies and observational constraints. It is important to study the properties of supermassive black holes and their host galaxies through both observations and simulations and compare their results in order to understand their physics and formative histories. We find that Illustris prediction for supermassive black hole mass relative to pitch angle is in rather good agreement with observations and that barred and non-barred galaxies follow similar scaling relations. Our work shows that Illustris presents very tight correlations between supermassive black hole mass and large-scale properties of the host galaxy, not only for early-type galaxies but also for low-mass, blue and star-forming galaxies. These tight relations beyond the bulge suggest that halo properties determine those of a disc galaxy and its supermassive black hole.

  12. The INTEGRAL Galactic bulge monitoring program: the first 1.5 years

    DEFF Research Database (Denmark)

    Kuulkers, E.; Shaw, S.E.; Paizis, A.

    2007-01-01

    Aims. The Galactic bulge region is a rich host of variable high-energy point sources. Since 2005, February 17 we are monitoring the source activity in the Galactic bulge region regularly and frequently, i.e., about every three days, with the instruments onboard INTEGRAL. Thanks to the large field...... of the monitoring up to 2006, April 21, i.e., for a period of about one and a half year, during three visibility seasons. We focus on the short (hour), medium (month) and long-term (year) variability in the hard X-ray bands, i.e., 20-60 keV and 60-150 keV. When available, we discuss the simultaneous observations......-2901b, IGR J17536-2339, and IGR J17541-2252. We report here on some of the high-energy properties of these sources. Conclusions. The high-energy light curves of all the sources in the field of view, and the high-energy images of the region, are made available through the WWW, as soon as possible after...

  13. Automated Guidance for Thermodynamics Essays: Critiquing versus Revisiting

    Science.gov (United States)

    Donnelly, Dermot F.; Vitale, Jonathan M.; Linn, Marcia C.

    2015-01-01

    Middle school students struggle to explain thermodynamics concepts. In this study, to help students succeed, we use a natural language processing program to analyze their essays explaining the aspects of thermodynamics and provide guidance based on the automated score. The 346 sixth-grade students were assigned to either the critique condition…

  14. Composition and Thermodynamic Properties of Air in Chemical Equilibrium

    Science.gov (United States)

    Moeckel, W E; Weston, Kenneth C

    1958-01-01

    Charts have been prepared relating the thermodynamic properties of air in chemical equilibrium for temperatures to 15,000 degrees k and for pressures 10(-5) to 10 (plus 4) atmospheres. Also included are charts showing the composition of air, the isentropic exponent, and the speed of sound. These charts are based on thermodynamic data calculated by the National Bureau of Standards.

  15. Partial Derivative Games in Thermodynamics: A Cognitive Task Analysis

    Science.gov (United States)

    Kustusch, Mary Bridget; Roundy, David; Dray, Tevian; Manogue, Corinne A.

    2014-01-01

    Several studies in recent years have demonstrated that upper-division students struggle with the mathematics of thermodynamics. This paper presents a task analysis based on several expert attempts to solve a challenging mathematics problem in thermodynamics. The purpose of this paper is twofold. First, we highlight the importance of cognitive task…

  16. On the forces and fluxes in non-equilibrium thermodynamics

    International Nuclear Information System (INIS)

    Kitahara, Kazuo

    1986-01-01

    A formulation of non-equilibrium thermodynamics of continuum systems based on local equilibrium assumption is reported. Thermodynamic forces are defined from a generalized local entropy and irreversible fluxes are defined as non-advective parts of fluxes of conservative quantities. The validity of the general evolution criterion and its generalization is discussed. (author)

  17. VizieR Online Data Catalog: CaT/[Fe/H] calibration for Galactic bulge stars (Vasquez+, 2015)

    Science.gov (United States)

    Vasquez, S.; Zoccali, M.; Hill, V.; Gonzalez, O. A.; Saviane, I.; Rejkuba, M.; Battaglia, G.

    2015-07-01

    The target stars we used to construct the CaT calibration are all located in Baade's Window, and they consist of two samples: 80 stars in the bulge RC and 68 stars on the RGB, which are ~0.7mag brigther than the RC. The medium-resolution spectra analysed here were taken with the FLAMES-GIRAFFE multifibre spectrograph at the VLT, in Medusa mode, within the ESO program ID 385.B-0735(B). Bulge data used to compute the metallicity calibration are presented. For each bulge star we provided the coordinates, magnitude difference respect to the red clump, equivalent widths for the two strongest calcium lines and the corresponding metallicity derived from high resolution spectroscopy. (1 data file).

  18. Thermodynamic Possibilities and Constraints of Pure Hydrogen Production by a Chromium, Nickel and Manganese-Based Chemical Looping Process at Lower Temperatures

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Siewiorek, A.; Baxter, D.; Rogut, J.; Punčochář, Miroslav

    2007-01-01

    Roč. 61, č. 2 (2007), s. 110-120 ISSN 0366-6352 Institutional research plan: CEZ:AV0Z40720504 Keywords : chromium * thermodynamics * hydrogen Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.367, year: 2007

  19. Thermodynamic characteristics of the acid-base equilibria of ethylenediamine- N, N'-diglutaric acid in aqueous solutions using calorimetric data

    Science.gov (United States)

    Gridchin, S. N.; Nikol'skii, V. M.

    2017-10-01

    The enthalpies of reaction of betaine group neutralization of ethylenediamine- N, N'-diglutaric acid (H4L) at 298.15 K and at different values of ionic strength of 0.1, 0.5, 1.0 (KNO3) is measured by direct calorimetry. The standard thermodynamic characteristics of the protolytic equilibria of H4L are calculated.

  20. Contact symmetries and Hamiltonian thermodynamics

    International Nuclear Information System (INIS)

    Bravetti, A.; Lopez-Monsalvo, C.S.; Nettel, F.

    2015-01-01

    It has been shown that contact geometry is the proper framework underlying classical thermodynamics and that thermodynamic fluctuations are captured by an additional metric structure related to Fisher’s Information Matrix. In this work we analyse several unaddressed aspects about the application of contact and metric geometry to thermodynamics. We consider here the Thermodynamic Phase Space and start by investigating the role of gauge transformations and Legendre symmetries for metric contact manifolds and their significance in thermodynamics. Then we present a novel mathematical characterization of first order phase transitions as equilibrium processes on the Thermodynamic Phase Space for which the Legendre symmetry is broken. Moreover, we use contact Hamiltonian dynamics to represent thermodynamic processes in a way that resembles the classical Hamiltonian formulation of conservative mechanics and we show that the relevant Hamiltonian coincides with the irreversible entropy production along thermodynamic processes. Therefore, we use such property to give a geometric definition of thermodynamically admissible fluctuations according to the Second Law of thermodynamics. Finally, we show that the length of a curve describing a thermodynamic process measures its entropy production

  1. On the application of thermodynamics of corrosion for service life design of concrete structures

    DEFF Research Database (Denmark)

    Küter, Andre; Geiker, Mette Rica; Møller, Per

    2010-01-01

    There are unexploited possibilities in the application of thermodynamics of corrosion for service life design (SLD) of concrete structures. Thermodynamics provides means for insightful descriptions of corrosion mechanisms and of corrosion protection mechanisms. Strategies for corrosion protection...... can be based on thermodynamically consistent corrosion mechanisms and evaluation of existing and design of new countermeasures can be performed using thermodynamics. Similarly, materials concepts for embedded electrodes can be designed using thermodynamics. The present paper provides a brief outline...... of the application of thermodynamics for SLD and gives examples of two applications: description of corrosion processes and design of countermeasures. Emphasis is set on chloride induced corrosion....

  2. A simple, fast and accurate thermodynamic-based approach for transfer and prediction of GC retention times between columns and instruments Part III: Retention time prediction on target column.

    Science.gov (United States)

    Hou, Siyuan; Stevenson, Keisean A J M; Harynuk, James J

    2018-03-27

    This is the third part of a three-part series of papers. In Part I we presented a method for determining the actual effective geometry of a reference column as well as the thermodynamic-based parameters of a set of probe compounds in an in-house mixture. Part II introduced an approach for estimating the actual effective geometry of a target column by collecting retention data of the same mixture of probe compounds on the target column and using their thermodynamic parameters, acquired on the reference column, as a bridge between both systems. Part III, presented here, demonstrates the retention time transfer and prediction from the reference column to the target column using experimental data for a separate mixture of compounds. To predict the retention time of a new compound we first estimate its thermodynamic-based parameters on the reference column (using geometric parameters determined previously). The compound's retention time on a second column (of previously determined geometry) is then predicted. The models and the associated optimization algorithms were tested using simulated and experimental data. The accuracy of predicted retention times shows that the proposed approach is simple, fast and accurate for retention time transfer and prediction between gas chromatography columns. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  3. Dynamically tunable transformation thermodynamics

    International Nuclear Information System (INIS)

    García-Meca, Carlos; Barceló, Carlos

    2016-01-01

    Recently, the introduction of transformation thermodynamics has provided a way to design thermal media that alter the flow of heat according to any spatial deformation, enabling the construction of novel devices such as thermal cloaks or concentrators. However, in its current version, this technique only allows static deformations of space. Here, we develop a space–time theory of transformation thermodynamics that incorporates the possibility of performing time-varying deformations. This extra freedom greatly widens the range of achievable effects, providing an additional degree of control for heat management applications. As an example, we design a reconfigurable thermal cloak that can be opened and closed dynamically, therefore being able to gradually adjust the temperature distribution of a given region. (paper)

  4. Thermodynamic problems on HCPWR

    International Nuclear Information System (INIS)

    Akiyama, Mie

    1986-01-01

    A HCPWR design uses the high compact lattice core of 1 to 2 mm fuel rod pitch in order to decrease the water volume fraction to fuel. But such high compactness is considered to cause the decrease of coolant flow rate due to the increase of core pressure loss. And the high compactness also affects the DNB phenomena itself which is directly related to the output performance. Moreover, the coolability of the reactor core is considered to be affected at an accident. It is one of the most important problems for realizing a HCPWR plant whether or not we can design a reactor that preserves the output performance under the consideration of such thermodynamic affections. The thermodynamic affections caused by high compactness are arranged in this report, and the further research problems on HCPWR are also considered on presently available knowledge. (author)

  5. Thermodynamics of Crystalline States

    CERN Document Server

    Fujimoto, Minoru

    2013-01-01

    Thermodynamics is a well-established discipline of physics for properties of matter in thermal equilibrium with the surroundings. Applying to crystals, however, the laws encounter undefined properties of crystal lattice, which therefore need to be determined for a clear and well-defined description of crystalline states. Thermodynamics of Crystalline States explores the roles played by order variables and dynamic lattices in crystals in a wholly new way. The book begins by clarifying basic concepts for stable crystals. Next, binary phase transitions are discussed to study collective motion of order variables, as described mostly as classical phenomena. New to this edition is the examination of magnetic crystals, where magnetic symmetry is essential for magnetic phase transitions. The multi-electron system is also discussed  theoretically, as a quantum-mechanical example, for superconductivity in metallic crystals. Throughout the book, the role played by the lattice is emphasized and studied in-depth. Thermod...

  6. Mechanics and thermodynamics

    CERN Document Server

    Demtröder, Wolfgang

    2017-01-01

    This introduction to classical mechanics and thermodynamics provides an accessible and clear treatment of the fundamentals. Starting with particle mechanics and an early introduction to special relativity this textbooks enables the reader to understand the basics in mechanics. The text is written from the experimental physics point of view, giving numerous real life examples and applications of classical mechanics in technology. This highly motivating presentation deepens the knowledge in a very accessible way. The second part of the text gives a concise introduction to rotational motion, an expansion to rigid bodies, fluids and gases. Finally, an extensive chapter on thermodynamics and a short introduction to nonlinear dynamics with some instructive examples intensify the knowledge of more advanced topics. Numerous problems with detailed solutions are perfect for self study.

  7. Fragile Thermodynamic Order

    International Nuclear Information System (INIS)

    Bernhoeft, N.; Lander, G.H.; Colineau, E.

    2003-01-01

    An asymmetric shift in the position of the magnetic Bragg peak with respect to the fiducial lattice has been observed by resonant X-ray scattering in a diverse series of antiferromagnetic compounds. This apparent violation of Bragg's law is interpreted in terms of a dynamically phased order parameter. We demonstrate the use of this effect as a novel probe of fragile or dynamic thermodynamic order in strongly correlated electronic systems. In particular, fresh light is shed on the paradoxical situation encountered in URu 2 Si 2 where the measured entropy gain on passing through T Neel is incompatible with the ground state moment estimated by neutron diffraction. The intrinsic space-time averaging of the probe used to characterise the thermodynamic macroscopic state may play a crucial and previously neglected role. In turn, this suggests the further use of resonant X-ray scattering in investigations of systems dominated by quantum fluctuations. (author)

  8. Thermodynamical quantum information sharing

    International Nuclear Information System (INIS)

    Wiesniak, M.; Vedral, V.; Brukner, C.

    2005-01-01

    Full text: Thermodynamical properties fully originate from classical physics and can be easily measured for macroscopic systems. On the other hand, entanglement is a widely spoken feature of quantum physics, which allows to perform certain task with efficiency unavailable with any classical resource. Therefore an interesting question is whether we can witness entanglement in a state of a macroscopic sample. We show, that some macroscopic properties, in particular magnetic susceptibility, can serve as an entanglement witnesses. We also study a mutual relation between magnetic susceptibility and magnetisation. Such a complementarity exhibits quantum information sharing between these two thermodynamical quantities. Magnetization expresses properties of individual spins, while susceptibility might reveal non-classical correlations as a witness. Therefore, a rapid change of one of these two quantities may mean a phase transition also in terms of entanglement. The complementarity relation is demonstrated by an analytical solution of an exemplary model. (author)

  9. Work reservoirs in thermodynamics

    Science.gov (United States)

    Anacleto, Joaquim

    2010-05-01

    We stress the usefulness of the work reservoir in the formalism of thermodynamics, in particular in the context of the first law. To elucidate its usefulness, the formalism is then applied to the Joule expansion and other peculiar and instructive experimental situations, clarifying the concepts of configuration and dissipative work. The ideas and discussions presented in this study are primarily intended for undergraduate students, but they might also be useful to graduate students, researchers and teachers.

  10. Thermodynamics of explosions

    OpenAIRE

    Neergaard, Gregers; Bondorf, Jakob P.; Mishustin, Igor N.

    2000-01-01

    We present our first attempts to formulate a thermodynamics-like description of explosions. The motivation is partly a fundamental interest in non-equilibrium statistical physics, partly the resemblance of an explosion to the late stages of a heavy-ion collision. We perform numerical simulations on a microscopic model of interacting billiard-ball like particles, and we analyse the results of such simulations trying to identify collective variables describing the degree of equilibrium during t...

  11. Understanding first law of thermodynamics through activities

    Science.gov (United States)

    Pathare, Shirish; Huli, Saurabhee; Ladage, Savita; Pradhan, H. C.

    2018-03-01

    The first law of thermodynamics involves several types of energies and many studies have shown that students lack awareness of them. They have difficulties in applying the law to different thermodynamic processes. These observations were confirmed in our pilot studies, carried out with students from undergraduate colleges across the whole of India. We, then, decided to develop an activity-based module to address students’ conceptual difficulties in this area. In particular, we took up the cases of both adiabatic and isothermal compression of an ideal gas. We tested, through a two-group pre and post test design, the effectiveness of the module.

  12. Preservation of thermodynamic structure in model reduction.

    Science.gov (United States)

    Öttinger, Hans Christian

    2015-03-01

    Based on the availability of an invariant manifold, we develop a model-reduction procedure that preserves thermodynamic structure. More concretely, we construct the Poisson and irreversible brackets of the general equation for the nonequilibrium reversible-irreversible coupling of nonequilibrium thermodynamics by means of the ideas originally introduced for handling constraints. The general ideas are then applied to the Kramers problem, that is, the description of transitions between two potential wells separated by a high barrier. This example reveals how a fortuitous cancellation mechanism that allows a logarithmic entropy to generate a linear diffusion equation is inherited by a master equation resulting from model reduction.

  13. Thermodynamic theory of dislocation-enabled plasticity

    Science.gov (United States)

    Langer, J. S.

    2017-11-01

    The thermodynamic theory of dislocation-enabled plasticity is based on two unconventional hypotheses. The first of these is that a system of dislocations, driven by external forces and irreversibly exchanging heat with its environment, must be characterized by a thermodynamically defined effective temperature that is not the same as the ordinary temperature. The second hypothesis is that the overwhelmingly dominant mechanism controlling plastic deformation is thermally activated depinning of entangled pairs of dislocations. This paper consists of a systematic reformulation of this theory followed by examples of its use in analyses of experimentally observed phenomena including strain hardening, grain-size (Hall-Petch) effects, yielding transitions, and adiabatic shear banding.

  14. Thermodynamics and statistical mechanics an integrated approach

    CERN Document Server

    Hardy, Robert J

    2014-01-01

    This textbook brings together the fundamentals of the macroscopic and microscopic aspects of thermal physics by presenting thermodynamics and statistical mechanics as complementary theories based on small numbers of postulates. The book is designed to give the instructor flexibility in structuring courses for advanced undergraduates and/or beginning graduate students and is written on the principle that a good text should also be a good reference. The presentation of thermodynamics follows the logic of Clausius and Kelvin while relating the concepts involved to familiar phenomena and the mod

  15. Maximum thermodynamic efficiency problem in batch distillation

    Directory of Open Access Journals (Sweden)

    J. C. Zavala-Loría

    2011-06-01

    Full Text Available A dynamic batch distillation study of the non-ideal mixture Ethanol-Water is presented. The objective of the study was to calculate an average thermodynamic efficiency of the process under an optimal constant reflux policy and the objective function includes a given production time in order to obtain the desired product quality (measured as the average mole fraction of the accumulated product. An expression for computing the thermodynamic efficiency is presented. The simulation of the column uses a mathematical model considering the complete dynamics of the operation and the problem of optimal control resulting in a non-linear programming problem. A dynamic optimization technique based on a SQP method was used to solve the problem. The average thermodynamic efficiency for the separation process under the conditions presented was 37.95%.

  16. Systematic vibration thermodynamic properties of bromine

    Science.gov (United States)

    Liu, G. Y.; Sun, W. G.; Liao, B. T.

    2015-11-01

    Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.

  17. Stochastic Thermodynamics: A Dynamical Systems Approach

    Directory of Open Access Journals (Sweden)

    Tanmay Rajpurohit

    2017-12-01

    Full Text Available In this paper, we develop an energy-based, large-scale dynamical system model driven by Markov diffusion processes to present a unified framework for statistical thermodynamics predicated on a stochastic dynamical systems formalism. Specifically, using a stochastic state space formulation, we develop a nonlinear stochastic compartmental dynamical system model characterized by energy conservation laws that is consistent with statistical thermodynamic principles. In particular, we show that the difference between the average supplied system energy and the average stored system energy for our stochastic thermodynamic model is a martingale with respect to the system filtration. In addition, we show that the average stored system energy is equal to the mean energy that can be extracted from the system and the mean energy that can be delivered to the system in order to transfer it from a zero energy level to an arbitrary nonempty subset in the state space over a finite stopping time.

  18. Consistent thermodynamic properties of lipids systems

    DEFF Research Database (Denmark)

    Cunico, Larissa; Ceriani, Roberta; Sarup, Bent

    Physical and thermodynamic properties of pure components and their mixtures are the basic requirement for process design, simulation, and optimization. In the case of lipids, our previous works[1-3] have indicated a lack of experimental data for pure components and also for their mixtures...... different pressures, with azeotrope behavior observed. Available thermodynamic consistency tests for TPx data were applied before performing parameter regressions for Wilson, NRTL, UNIQUAC and original UNIFAC models. The relevance of enlarging experimental databank of lipids systems data in order to improve...... the performance of predictive thermodynamic models was confirmed in this work by analyzing the calculated values of original UNIFAC model. For solid-liquid equilibrium (SLE) data, new consistency tests have been developed [2]. Some of the developed tests were based in the quality tests proposed for VLE data...

  19. Thermodynamics principles characterizing physical and chemical processes

    CERN Document Server

    Honig, Jurgen M

    1999-01-01

    This book provides a concise overview of thermodynamics, and is written in a manner which makes the difficult subject matter understandable. Thermodynamics is systematic in its presentation and covers many subjects that are generally not dealt with in competing books such as: Carathéodory''s approach to the Second Law, the general theory of phase transitions, the origin of phase diagrams, the treatment of matter subjected to a variety of external fields, and the subject of irreversible thermodynamics.The book provides a first-principles, postulational, self-contained description of physical and chemical processes. Designed both as a textbook and as a monograph, the book stresses the fundamental principles, the logical development of the subject matter, and the applications in a variety of disciplines. This revised edition is based on teaching experience in the classroom, and incorporates many exercises in varying degrees of sophistication. The stress laid on a didactic, logical presentation, and on the relat...

  20. Sustainable Development within Planetary Boundaries: A Functional Revision of the Definition Based on the Thermodynamics of Complex Social-Ecological Systems

    Directory of Open Access Journals (Sweden)

    Bart Muys

    2013-05-01

    Full Text Available The dominant paradigm of sustainable development (SD where the environment is just the third pillar of SD has proven inadequate to keep humanity within the safe operational space determined by biophysical planetary boundaries. This implies the need for a revised definition compatible with a nested model of sustainable development, where humanity forms part of the overall social-ecological system, and that would allow more effective sustainable development goals and indicators. In this paper an alternative definition is proposed based on the thermodynamics of open systems applied to ecosystems and human systems. Both sub- systems of the global social-ecological system show in common an increased capability of buffering against disturbances as a consequence of an internal increase of order. Sustainable development is considered an optimization exercise at different scales in time and space based on monitoring the change in the exergy content and exergy dissipation of these two sub- systems of the social-ecological system. In common language it is the increase of human prosperity and well-being without loss of the structure and functioning of the ecosystem. This definition is functional as it allows the straightforward selection of quantitative indicators, discerning sustainable development from unsustainable development, unsustainable stagnation and sustainable retreat. The paper shows that the new definition is compatible with state of the art thinking on ecosystem services, the existence of regime shifts and societal transitions, and resilience. One of the largest challenges in applying the definition is our insufficient understanding of the change in ecosystem structure and function as an endpoint indicator of human action, and its effect on human prosperity and well-being. This implies the continued need to use midpoint indicators of human impact and related thresholds defining the safe operating space of the present generation with respect to