40,041 research outputs found
Probing the QCD Critical Point with Higher Moments of Net-proton Multiplicity Distributions
Higher moments of event-by-event net-proton multiplicity distributions are
applied to search for the QCD critical point in the heavy ion collisions. It
has been demonstrated that higher moments as well as moment products are
sensitive to the correlation length and directly connected to the thermodynamic
susceptibilities computed in the Lattice QCD and Hadron Resonance Gas (HRG)
model. In this paper, we will present measurements for kurtosis (),
skewness () and variance () of net-proton multiplicity
distributions at the mid-rapidity () and GeV/ for
Au+Au collisions at =19.6, 39, 62.4, 130 and 200 GeV, Cu+Cu
collisions at =22.4, 62.4 and 200 GeV, d+Au collisions at
=200 GeV and p+p collisions at =62.4 and 200 GeV.
The moment products and of net-proton
distributions, which are related to volume independent baryon number
susceptibility ratio, are compared to the Lattice QCD and HRG model
calculations. The and of net-proton
distributions are consistent with Lattice QCD and HRG model calculations at
high energy, which support the thermalization of the colliding system.
Deviations of and for the Au+Au collisions at
low energies from HRG model calculations are also observed.Comment: 10 pages, 8 figures, Proceedings of 27th Winter Workshon on Nuclear
Dynamics. Feb. 6-13 (2011
Improved lattice QCD with quarks: the 2 dimensional case
QCD in two dimensions is investigated using the improved fermionic lattice
Hamiltonian proposed by Luo, Chen, Xu, and Jiang. We show that the improved
theory leads to a significant reduction of the finite lattice spacing errors.
The quark condensate and the mass of lightest quark and anti-quark bound state
in the strong coupling phase (different from t'Hooft phase) are computed. We
find agreement between our results and the analytical ones in the continuum.Comment: LaTeX file (including text + 10 figures
Study of solvent-based carbon capture for cargo ships through process modelling and simulation
Controlling anthropogenic CO2 emission is crucial to mitigate global warming. Marine CO2 emissions accounts for around 3% of the total CO2 emission worldwide and grows rapidly with increasing demand for passenger and cargo transport. The International Maritime Organization (IMO) has adopted mandatory measures to reduce greenhouse gases (GHGs) emissions from international shipping. This study aims to explore how to apply solvent-based post-combustion carbon capture (PCC) process to capture CO2 from the energy system in a typical cargo ship and to evaluate the cost degrees of different integration options through simulation-based techno-economic assessments. The selected reference cargo ship has a propulsion system consisting of two four-stroke reciprocating engines at a total power of 17 MW. The study first addressed the challenge on model development of the marine diesel engines and then developed the model of the ship energy system. The limitations of implementing onboard carbon capture were discussed. Two integration options between the ship energy system and the carbon capture process were simulated to analyse the thermal performance of the integrated system and to estimate equipment size of the carbon capture process. It was found that the carbon capture level could only reach 73% when the existing ship energy system is integrated with the PCC process due to limited heat and electricity supply for CCS. The cost of CO2 captured is around 77.50 €/ton CO2. With installation of an additional gas turbine to provide extra energy utilities to the capture plant, the carbon capture level could reach 90% whilst the cost of CO2 captured is around 163.07 €/ton CO2, mainly because of 21.41% more fuel consumption for the additional diesel gas turbine. This is the first systematical study in applying solvent-based carbon capture for ships, which will inspire other researchers in this area
Monte Carlo Hamiltonian of lattice gauge theory
We discuss how the concept of the Monte Carlo Hamiltonian can be applied to
lattice gauge theories.Comment: "Non-Perturbative Quantum Field Theory: Lattice and Beyond",
Guangzhou, China 200
Oxygen Isotope Effect on the Spin State Transition in (PrSm)CaCoO
Oxygen isotope substitution is performed in the perovskite cobalt oxide
(PrSm)CaCoO which shows a sharp spin
state transition from the intermediate spin (IS) state to the low spin (LS)
state at a certain temperature. The transition temperature of the spin state
up-shifts with the substitution of by O from the resistivity
and magnetic susceptibility measurements. The up-shift value is 6.8 K and an
oxygen isotope exponent () is about -0.8. The large oxygen isotope
effect indicates strong electron-phonon coupling in this material. The
substitution of O by O leads to a decrease in the frequency of
phonon and an increase in the effective mass of electron (), so that
the bandwidth W is decreased and the energy difference between the different
spin states is increased. This is the reason why the is shifted to high
temperature with oxygen isotopic exchange.Comment: 4 pages, 3 figure
- …