The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform

Ludwik Adamowicz - One of the best experts on this subject based on the ideXlab platform.

  • Algorithms for calculating Mass-Velocity and Darwin relativistic corrections with n-electron explicitly correlated Gaussians with shifted centers
    The Journal of Chemical Physics, 2016
    Co-Authors: Monika Stanke, Ewa Palikot, Ludwik Adamowicz
    Abstract:

    Algorithms for calculating the leading Mass-Velocity (MV) and Darwin (D) relativistic corrections are derived for electronic wave functions expanded in terms of n-electron explicitly correlated Gaussian functions with shifted centers and without pre-exponential angular factors. The algorithms are implemented and tested in calculations of MV and D corrections for several points on the ground-state potential energy curves of the H2 and LiH molecules. The algorithms are general and can be applied in calculations of systems with an arbitrary number of electrons.

  • Darwin and Mass-Velocity relativistic corrections in non-Born-Oppenheimer variational calculations
    The Journal of chemical physics, 2006
    Co-Authors: Dariusz Kędziera, Monika Stanke, Sergiy Bubin, Maria Barysz, Ludwik Adamowicz
    Abstract:

    The Pauli approach to account for the Mass-Velocity and Darwin relativistic corrections has been applied to the formalism for quantum mechanical molecular calculations that does not assume the Born-Oppenheimer (BO) approximation regarding separability of the electronic and nuclear motions in molecular systems. The corrections are determined using the first order perturbation theory and are derived for the non-BO wave function of a diatomic system expressed in terms of explicitly correlated Gaussian functions with premultipliers in the form of even powers of the internuclear distance. As a numerical example we used calculations of the transition energies for pure vibrational states of the HD+ ion.

  • Darwin and Mass-Velocity relativistic corrections in the non-Born-Oppenheimer calculations of pure vibrational states of H2.
    The Journal of chemical physics, 2006
    Co-Authors: Dariusz Kȩdziera, Sergiy Bubin, Monika Stanke, Maria Barysz, Ludwik Adamowicz
    Abstract:

    The Darwin and Mass-Velocity relativistic corrections have been calculated for all pure vibrational states of the H2 using the perturbation theory and very accurate variational wave functions obtained without assuming the Born-Oppenheimer (BO) approximation. Expansions in terms of explicitly correlated Gaussians with premultipliers in the form of even powers of the internuclear distance were used for the wave functions. With the inclusion of the two relativistic corrections to the non-BO energies the transition energies for the highest states agree more with the experimental results.

D Kelson - One of the best experts on this subject based on the ideXlab platform.

  • clash vlt the Mass Velocity anisotropy and pseudo phase space density profiles of the z 0 44 galaxy cluster macs j1206 2 0847
    Astronomy and Astrophysics, 2013
    Co-Authors: A Biviano, Piero Rosati, I Balestra, Matteo Girardi, M Nonino, Caterina Grillo, M Scodeggio, Doron Lemze, Andrea Mercurio, D Kelson
    Abstract:

    Aims. We constrain the Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing.Methods. We use an unprecedented data-set of ≃600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster Mass profile over the radial range ~0–5 Mpc (0–2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the Velocity-anisotropy profiles of cluster members. With the Mass-density and Velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile.Results. The kinematics and lensing determinations of the cluster Mass profile are in excellent agreement. This is very well fitted by a NFW model with Mass M200 = (1.4 ± 0.2) × 1015 M⊙ and concentration c200 = 6 ± 1, only slightly higher than theoretical expectations. Other Mass profile models also provide acceptable fits to our data, of (slightly) lower (Burkert, Hernquist, and Softened Isothermal Sphere) or comparable (Einasto) quality than NFW. The Velocity anisotropy profiles of the passive and star-forming cluster members are similar, close to isotropic near the center and increasingly radial outside. Passive cluster members follow extremely well the theoretical expectations for the pseudo-phase-space density profile and the relation between the slope of the Mass-density profile and the Velocity anisotropy. Star-forming cluster members show marginal deviations from theoretical expectations.Conclusions. This is the most accurate determination of a cluster Mass profile out to a radius of 5 Mpc, and the only determination of the Velocity-anisotropy and pseudo-phase-space density profiles of both passive and star-forming galaxies for an individual cluster. These profiles provide constraints on the dynamical history of the cluster and its galaxies. Prospects for extending this analysis to a larger cluster sample are discussed.

  • CLASH-VLT: The Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy cluster MACS J1206.2-0847
    Astronomy and Astrophysics - A&A, 2013
    Co-Authors: A Biviano, Piero Rosati, I Balestra, M Nonino, M Scodeggio, Doron Lemze, Amata Mercurio, Marisa Girardi, Claudio Grillo, D Kelson
    Abstract:

    Aims. We constrain the Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing.Methods. We use an unprecedented data-set of ≃600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster Mass profile over the radial range ~0–5 Mpc (0–2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the Velocity-anisotropy profiles of cluster members. With the Mass-density and Velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile.Results. The kinematics and lensing determinations of the cluster Mass profile are in excellent agreement. This is very well fitted by a NFW model with Mass M200 = (1.4 ± 0.2) × 1015 M⊙ and concentration c200 = 6 ± 1, only slightly higher than theoretical expectations. Other Mass profile models also provide acceptable fits to our data, of (slightly) lower (Burkert, Hernquist, and Softened Isothermal Sphere) or comparable (Einasto) quality than NFW. The Velocity anisotropy profiles of the passive and star-forming cluster members are similar, close to isotropic near the center and increasingly radial outside. Passive cluster members follow extremely well the theoretical expectations for the pseudo-phase-space density profile and the relation between the slope of the Mass-density profile and the Velocity anisotropy. Star-forming cluster members show marginal deviations from theoretical expectations.Conclusions. This is the most accurate determination of a cluster Mass profile out to a radius of 5 Mpc, and the only determination of the Velocity-anisotropy and pseudo-phase-space density profiles of both passive and star-forming galaxies for an individual cluster. These profiles provide constraints on the dynamical history of the cluster and its galaxies. Prospects for extending this analysis to a larger cluster sample are discussed.

  • CLASH-VLT: The Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy
    2013
    Co-Authors: A Biviano, I Balestra, M Nonino, M Scodeggio, Doron Lemze, D Kelson, Amata Mercurio, Marisa Girardi, Claudio Grillo, Adi Zitrin
    Abstract:

    Aims. We constrain the Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing. Methods. We use an unprecedented data-set of � 600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster Mass profile over the radial range ∼0‐5 Mpc (0‐2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the Velocity-anisotropy profiles of cluster members. With the Mass-density and Velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile. Results. The kinematics and lensing determinations of the cluster Mass profile are in excellent agreement. This is very well fitted by a NFW model

Xiaojing Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Experimental study on the pressure drop characteristics of steam-water two-phase flow at a low Mass Velocity in a four-head rifled tube
    Applied Thermal Engineering, 2017
    Co-Authors: Xiaojing Zhu, Zhuqiang Yang
    Abstract:

    Abstract The pressure drop characteristics of steam-water two-phase flow at a low Mass Velocity in a four-head rifled tube were experimentally studied under an adiabatic condition with pressure ranging from 11.3 to 21.5 MPa, Mass Velocity ranging from 250 to 1200 kg/m 2  s, and steam quality ranging from 0 to 1. A test section composed of a 2000 mm long horizontal tube and 3500 mm long vertical tube was set up to fully evaluate the pressure drop characteristics, including the gravitational pressure drop and frictional pressure drop. It was found that the self-compensating characteristic is present in the four-head rifled tube when the Mass Velocity is lower than a certain critical value. The major parameters affecting the two-phase multiplier are pressure and steam quality. The two-phase multiplier increases with increasing steam quality and decreases with increasing pressure. In the near-critical pressure region, the two-phase frictional pressure drop approaches that of single phase flow because the density difference between water and steam is small. A new correlation for the two-phase multiplier for the frictional pressure drop of steam-water two-phase flow in the four-head rifled tube was proposed based on a total of 516 experimental data points, with a root mean square error of less than 20%. Comparing these results with previous correlations, the two-phase frictional pressure drop in the rifled tube is lower than those studied by previous scholars under low-Velocity conditions, especially in the high steam quality region. The results provide instructive guidelines to improve the design and operational safety of a supercritical circulating fluidized bed boiler.

  • Heat sensitivity of vertical water wall at low Mass Velocity in supercritical pressure W-shaped flame boiler
    International Journal of Thermal Sciences, 2012
    Co-Authors: Weishu Wang, Xiaojing Zhu, Jintao Huang
    Abstract:

    The vertical water wall of the once-through boiler is sensitive to heat disturbance because of its smaller water volume compared with the drum boiler. This paper deduced formulas of the sensitivity coefficient of flow and output enthalpy, and made a heat sensitivity analysis for the vertical water wall of a 600 MW supercritical pressure W-shaped flame boiler at a low Mass Velocity when heat disturbance occurs. It was found that the flow sensitivity coefficient decreases and the outlet enthalpy sensitivity coefficient increases with increasing steam quality. Increasing Mass Velocity weakens the flow sensitivity and enhances the outlet enthalpy sensitivity. When the Mass Velocity exceeds a certain value, the flow sensitivity coefficient is less than zero. Increasing heat flux leads to an increase in the flow sensitivity coefficient and a decrease in the outlet enthalpy sensitivity coefficient. In the condition of low steam quality, the flow sensitivity weakens and outlet enthalpy sensitivity strengthens when the pressure is up to 22 MPa. Moreover, when the quality is high, rising pressure strengthens the flow sensitivity and weakens the outlet enthalpy sensitivity. The study has provided some instructive findings, which may be helpful for the safety operation of the 600 MW supercritical pressure W-shaped flame boiler.

  • Self-compensating characteristic of steam–water mixture at low Mass Velocity in vertical upward parallel internally ribbed tubes
    Applied Thermal Engineering, 2010
    Co-Authors: Xiaojing Zhu, Dong Yang, Jianguo Wang
    Abstract:

    Abstract This paper presents an experimental investigation on Self-Compensating Characteristic (SCC) in vertical upward parallel tubes with low Mass Velocity of steam–water two-phase mixture. A physical model was built up using parallel internally ribbed tubes. A method called Differential Pressure Substitute was used to measure two-phase flow parameters. The results indicated that the SCC of vertical upward parallel tubes is caused by combined action of frictional pressure drop and gravitational pressure drop. The Mass Velocity in the tube with lower heat flux decreases first, and then increases with an increase in quality. The uneven heat fluxes among tubes are the main reasons that cause Mass Velocity differentials. Greater uneven heating ratio enhances the SCC in low quality region and weakens it in high quality region. The SCC has different variation rules in different pressure region. In the sub-critical pressure region, rising pressure weakens the SCC when quality is low and enhances it when quality is high. In near-critical pressure region, the Mass Velocity varies monotonically and slowly with the increase in quality because the difference between water and steam is minor in this pressure region. The results provide some instructive advices to improve the design and operation safety of once-through boiler.

Monika Stanke - One of the best experts on this subject based on the ideXlab platform.

  • Algorithms for calculating Mass-Velocity and Darwin relativistic corrections with n-electron explicitly correlated Gaussians with shifted centers
    The Journal of Chemical Physics, 2016
    Co-Authors: Monika Stanke, Ewa Palikot, Ludwik Adamowicz
    Abstract:

    Algorithms for calculating the leading Mass-Velocity (MV) and Darwin (D) relativistic corrections are derived for electronic wave functions expanded in terms of n-electron explicitly correlated Gaussian functions with shifted centers and without pre-exponential angular factors. The algorithms are implemented and tested in calculations of MV and D corrections for several points on the ground-state potential energy curves of the H2 and LiH molecules. The algorithms are general and can be applied in calculations of systems with an arbitrary number of electrons.

  • Darwin and Mass-Velocity relativistic corrections in non-Born-Oppenheimer variational calculations
    The Journal of chemical physics, 2006
    Co-Authors: Dariusz Kędziera, Monika Stanke, Sergiy Bubin, Maria Barysz, Ludwik Adamowicz
    Abstract:

    The Pauli approach to account for the Mass-Velocity and Darwin relativistic corrections has been applied to the formalism for quantum mechanical molecular calculations that does not assume the Born-Oppenheimer (BO) approximation regarding separability of the electronic and nuclear motions in molecular systems. The corrections are determined using the first order perturbation theory and are derived for the non-BO wave function of a diatomic system expressed in terms of explicitly correlated Gaussian functions with premultipliers in the form of even powers of the internuclear distance. As a numerical example we used calculations of the transition energies for pure vibrational states of the HD+ ion.

  • Darwin and Mass-Velocity relativistic corrections in the non-Born-Oppenheimer calculations of pure vibrational states of H2.
    The Journal of chemical physics, 2006
    Co-Authors: Dariusz Kȩdziera, Sergiy Bubin, Monika Stanke, Maria Barysz, Ludwik Adamowicz
    Abstract:

    The Darwin and Mass-Velocity relativistic corrections have been calculated for all pure vibrational states of the H2 using the perturbation theory and very accurate variational wave functions obtained without assuming the Born-Oppenheimer (BO) approximation. Expansions in terms of explicitly correlated Gaussians with premultipliers in the form of even powers of the internuclear distance were used for the wave functions. With the inclusion of the two relativistic corrections to the non-BO energies the transition energies for the highest states agree more with the experimental results.

A Biviano - One of the best experts on this subject based on the ideXlab platform.

  • clash vlt the Mass Velocity anisotropy and pseudo phase space density profiles of the z 0 44 galaxy cluster macs j1206 2 0847
    Astronomy and Astrophysics, 2013
    Co-Authors: A Biviano, Piero Rosati, I Balestra, Matteo Girardi, M Nonino, Caterina Grillo, M Scodeggio, Doron Lemze, Andrea Mercurio, D Kelson
    Abstract:

    Aims. We constrain the Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing.Methods. We use an unprecedented data-set of ≃600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster Mass profile over the radial range ~0–5 Mpc (0–2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the Velocity-anisotropy profiles of cluster members. With the Mass-density and Velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile.Results. The kinematics and lensing determinations of the cluster Mass profile are in excellent agreement. This is very well fitted by a NFW model with Mass M200 = (1.4 ± 0.2) × 1015 M⊙ and concentration c200 = 6 ± 1, only slightly higher than theoretical expectations. Other Mass profile models also provide acceptable fits to our data, of (slightly) lower (Burkert, Hernquist, and Softened Isothermal Sphere) or comparable (Einasto) quality than NFW. The Velocity anisotropy profiles of the passive and star-forming cluster members are similar, close to isotropic near the center and increasingly radial outside. Passive cluster members follow extremely well the theoretical expectations for the pseudo-phase-space density profile and the relation between the slope of the Mass-density profile and the Velocity anisotropy. Star-forming cluster members show marginal deviations from theoretical expectations.Conclusions. This is the most accurate determination of a cluster Mass profile out to a radius of 5 Mpc, and the only determination of the Velocity-anisotropy and pseudo-phase-space density profiles of both passive and star-forming galaxies for an individual cluster. These profiles provide constraints on the dynamical history of the cluster and its galaxies. Prospects for extending this analysis to a larger cluster sample are discussed.

  • CLASH-VLT: The Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy cluster MACS J1206.2-0847
    Astronomy and Astrophysics - A&A, 2013
    Co-Authors: A Biviano, Piero Rosati, I Balestra, M Nonino, M Scodeggio, Doron Lemze, Amata Mercurio, Marisa Girardi, Claudio Grillo, D Kelson
    Abstract:

    Aims. We constrain the Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing.Methods. We use an unprecedented data-set of ≃600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster Mass profile over the radial range ~0–5 Mpc (0–2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the Velocity-anisotropy profiles of cluster members. With the Mass-density and Velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile.Results. The kinematics and lensing determinations of the cluster Mass profile are in excellent agreement. This is very well fitted by a NFW model with Mass M200 = (1.4 ± 0.2) × 1015 M⊙ and concentration c200 = 6 ± 1, only slightly higher than theoretical expectations. Other Mass profile models also provide acceptable fits to our data, of (slightly) lower (Burkert, Hernquist, and Softened Isothermal Sphere) or comparable (Einasto) quality than NFW. The Velocity anisotropy profiles of the passive and star-forming cluster members are similar, close to isotropic near the center and increasingly radial outside. Passive cluster members follow extremely well the theoretical expectations for the pseudo-phase-space density profile and the relation between the slope of the Mass-density profile and the Velocity anisotropy. Star-forming cluster members show marginal deviations from theoretical expectations.Conclusions. This is the most accurate determination of a cluster Mass profile out to a radius of 5 Mpc, and the only determination of the Velocity-anisotropy and pseudo-phase-space density profiles of both passive and star-forming galaxies for an individual cluster. These profiles provide constraints on the dynamical history of the cluster and its galaxies. Prospects for extending this analysis to a larger cluster sample are discussed.

  • CLASH-VLT: The Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy
    2013
    Co-Authors: A Biviano, I Balestra, M Nonino, M Scodeggio, Doron Lemze, D Kelson, Amata Mercurio, Marisa Girardi, Claudio Grillo, Adi Zitrin
    Abstract:

    Aims. We constrain the Mass, Velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing. Methods. We use an unprecedented data-set of � 600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster Mass profile over the radial range ∼0‐5 Mpc (0‐2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the Velocity-anisotropy profiles of cluster members. With the Mass-density and Velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile. Results. The kinematics and lensing determinations of the cluster Mass profile are in excellent agreement. This is very well fitted by a NFW model