Search results for "THERMODYNAMICS"
showing 10 items of 2774 documents
Charge measurement of dust particles on photovoltaic module
2013
Photovoltaic (PV) systems are one of the most promising renewable energy sources in the world, and hence it is important to explore the factors that affect the working / operational efficiency of this source. Many factors can affect the efficiency of the solar cells such as: dust accumulation on the surface of the arrays; cell material; shading; tilt angle of the cells; orientation of the PV modules and cell temperatures. This research is focused on the analyzing the effect of charged dust particles on the PV module performance. A number of studies have demonstrated the effect of dust accumulation on the PV modules' performance. But the relation between the amounts of charge of the dust par…
Fractional-Order Theory of Thermoelasticity. II: Quasi-Static Behavior of Bars
2018
This work aims to shed light on the thermally-anomalous coupled behavior of slightly deformable bodies, in which the strain is additively decomposed in an elastic contribution and in a thermal part. The macroscopic heat flux turns out to depend upon the time history of the corresponding temperature gradient, and this is the result of a multiscale rheological model developed in Part I of the present study, thereby resembling a long-tail memory behavior governed by a Caputo's fractional operator. The macroscopic constitutive equation between the heat flux and the time history of the temperature gradient does involve a power law kernel, resulting in the anomaly mentioned previously. The interp…
Non-classical Velocity Statistics in Counterflow Quantum Turbulence
2014
In this work we analyse the statistical distribution of turbulent superfluid velocity components in a He II counterflow channel, via two-dimensional numerical simulations pre- sented in past studies. The Probability Density Functions (PDFs) of the superfluid velocity components are investigated at lengthscales smaller than the average intervortex spacing, for varying vortex densities and different wall-normal distances. The results obtained con- firm the non-classical signature of quantum turbulence already observed in past numerical studies.
Theρ(ω)/B*(B) system and bound states in the unitary local Hidden Gauge approach
2016
In this work, we study systems composed of a ρ/ω and B* meson pair. We find three bound states in isospin, spin-parity channels (1/2, 0+ ), (1/2, 1+ ) and (1/2, 2+ ). The state with J = 2 can be a good candidate for the B * 2 (5747). We also study the ρB system, and a bound state with mass 5728 MeV and width around 20 MeV is obtained, which can be identified with the B 1 (5721) resonance. In the case of I = 3/2, one obtains repulsion and thus, no exotic (molecular) mesons in this sector are generated in the approach.
Initial state anisotropies in ultrarelativistic heavy-ion collisions from the Monte Carlo Glauber model
2012
In hydrodynamicalmodeling of heavy-ion collisions the initial state spatial anisotropies translate into momentum anisotropies of the final state particle distributions. Thus, understanding the origin of the initial anisotropies and quantifying their uncertainties is important for the extraction of specific QCD matter properties, such as viscosity, from the experimental data. In this work we study the wounded nucleon approach in the Monte Carlo Glauber model framework, focusing especially on the uncertainties which arise from the modeling of the nucleon-nucleon interactions between the colliding nucleon pairs and nucleon-nucleon correlations inside the colliding nuclei. We compare the black …
Approximate NNLO predictions for the stop-pair production cross section at the LHC
2013
If the minimal supersymmetric standard model at scales of around 1 TeV is realized in nature, the total top-squark pair production cross section should be measurable at the CERN Large Hadron Collider. In this work we present precise predictions for this observable, which are based upon approximate NNLO formulas obtained using soft-collinear effective theory methods.
THE LIMITING EFFICIENCY OF FOUR-BAND CELLS REVISITED
2014
The limiting theoretical efficiency of four-band solar cells is revisited. In previous work, researchers have looked at the theoretical efficiency of four band cells where the smallest of the three sub-band gaps is closest to the valence band and the largest closest to the conduction band. In this work, limits are calculated also for other possible band configurations. In multi-band cells, photon selectivity can be assured by adjusting the band widths. The present work shows that previous authors have put too rigid constraints on the band structure to achieve spectral selectivity. Relieving these constraints gives a considerably higher limiting efficiency for cells with band width restricti…
Numerical Simulations and Diagnostics in Astrophysics: A few Magnetohydrodynamics Examples
2007
We discuss some issues related to numerical simulations in Astrophysics and, in particular, to their use both as a theoretical tool and as a diagnostic tool, to gain insight into the physical phenomena at work. We make our point presenting some examples of Magneto-hydro-dynamic (MHD) simulations of astrophysical plasmas and illustrating their use. In particular we show the need for appropriate tools to interpret, visualize and present results in an adequate form, and the importance of spectral synthesis for a direct comparison with observations.
Dynamics of a Quantum Particle in Asymmetric Bistable Potential with Environmental Noise
2011
In this work we analyze the dynamics of a quantum particle subject to an asymmetric bistable potential and interacting with a thermal reservoir. We obtain the time evolution of the population distributions in both energy and position eigenstates of the particle, for different values of the coupling strength with the thermal bath. The calculation is carried out using the Feynman-Vernon functional under the discrete variable representation.
A geometric analysis of the effects of noise on Berry phase
2007
In this work we describe the effect of classical and quantum noise on the Berry phase. It is not a topical review article but rather an overview of our work in this field aiming at giving a simple pictorial intuition of our results.