Effects Of Energy Loss Research Articles

Design of Hybrid Power Systems with Energy Losses

The application of Process Integration using the Pinch Analysis technique has been recently extended to the design of hybrid power systems to determine the maximum power recovery and the battery storage capacity. The graphical and the numerical Power Pinch Analysis (PoPA) tools provide designers with visualisation tools that are systematic and simple to implement for the optimisation of power systems. However, the power losses incurred in the systems, have so far, not been considered in detail in the previous works. This paper extends the PoPA method by considering the power losses that occur during the power system's conversion, transfer and storage. The effects of the losses on the minimum outsourced electricity targets and the storage capacity are evaluated. The Storage Cascade Table (SCT) of PoPA has been further developed to include the effect of energy losses in the system's design. Application of the developed method on a case study yields the more realistic power targets for off-grid hybrid power systems.

J/ψSuppression inp−ACollisions from Parton Energy Loss in Cold QCD Matter

The effects of energy loss in cold nuclear matter on J/ψ suppression in p-A collisions are studied. A simple model based on first principles and depending on a single free parameter is able to reproduce J/ψ suppression data at large x(F) and at various center-of-mass energies. These results strongly support energy loss as a dominant effect in quarkonium suppression. They also give some hint on its hadroproduction mechanism suggesting color neutralization to happen on long time scales. Predictions for J/ψ and Υ suppression in p-Pb collisions at the LHC are made.

Monte Carlo approach for hadron azimuthal correlations in high energy proton and nuclear collisions

We use a Monte Carlo approach to study hadron azimuthal angular correlations in high energy proton-proton and central nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) energies at mid-rapidity. We build a hadron event generator that incorporates the production of $2\to 2$ and $2\to 3$ parton processes and their evolution into hadron states. For nucleus-nucleus collisions we include the effect of parton energy loss in the Quark-Gluon Plasma using a modified fragmentation function approach. In the presence of the medium, for the case when three partons are produced in the hard scattering, we analyze the Monte Carlo sample in parton and hadron momentum bins to reconstruct the angular correlations. We characterize this sample by the number of partons that are able to hadronize by fragmentation within the selected bins. In the nuclear environment the model allows hadronization by fragmentation only for partons with momentum above a threshold $p_T^{{\tiny{thresh}}}=2.4$ GeV. We argue that one should treat properly the effect of those partons with momentum below the threshold, since their interaction with the medium may lead to showers of low momentum hadrons along the direction of motion of the original partons as the medium becomes diluted.

Nuclear modification factor for heavy flavors: An energy loss effect or more baryons than mesons?

The properties of the nuclear modification factor for heavy flavors are usually attributed to the energy loss suffered by the heavy quark propagating in a QCD plasma. Nevertheless it is a bit surprising that the suppression of this factor is as strong as the one suffered by light flavors. In this work we show that when accounting for the momentum shift associated to the opening of the recombination channel to produce hadrons in the QCD plasma, it is not necessary to invoke such a strong energy loss. We show that when the heavy baryon to meson ratio is larger in nuclear than in proton collisions, data from RHIC and LHC for the nuclear modification factor of electrons coming from heavy flavor decays as well as for charmed masons can be accounted for.

Ion-beam-treated strained AlGaN/GaN multi-quantum wells: HAADF-STEM, HRTEM, Raman and HRXRD characterizations

Ion beams are extensively used for the modification and analysis of a wide range of materials. However, basic mechanisms of defect propagation with the effect of different electronic energy losses are not understood yet and are essential to improve device performance. In the present study, AlGaN/GaN multi-quantum wells (MQWs), which were grown on sapphire by metal organic chemical vapor deposition, have been subjected to swift heavy ion irradiation at a fixed fluence as a function of type of projectile and its energy to understand the defect formation. Irradiated materials have been compared with the as-deposited ones to see the effects on composition, periodicity and strain. The composition gradient as a function of S e has been investigated with analytical and high-angle annular dark field scanning transmission electron microscopy (TEM) and the results have been further confirmed by high-resolution X-ray diffraction. The interface quality has been analyzed with aberration-corrected high-resolution TEM images. Effects of electronic energy loss on Raman modes have been investigated. Finally, the effects of ion beams on MQWs interfaces are discussed.

Model for nonlinear evolution of localized ion ring beam in magnetoplasma

An electrostatic hybrid model, which investigates the nonlinear evolution of a localized ion ring beam in a magnetoplasma, is described and applied to the generation and evolution of turbulence in the very low frequency (VLF) (Ωci<ω<Ωce) range, where Ωci(e) is the ion (electron) gyro frequency. Electrons are treated as a fluid and the ions with the particle-in-cell method. Although the model is electrostatic, it includes the effects of energy loss by convection of electromagnetic VLF waves out of the instability region by utilizing a phenomenological model for effective collisions with the fluid electrons. In comparison with a more conventional electrostatic hybrid model, the new model shows much more efficient extraction of energy from the ion ring beam and reduced background plasma heating over a range of parameters.

Improvement of Depth Resolution of ADF-SCEM by Deconvolution: Effects of Electron Energy Loss and Chromatic Aberration on Depth Resolution

Scanning confocal electron microscopy (SCEM) is a new imaging technique that is capable of depth sectioning with nanometer-scale depth resolution. However, the depth resolution in the optical axis direction (Z) is worse than might be expected on the basis of the vertical electron probe size calculated with the existence of spherical aberration. To investigate the origin of the degradation, the effects of electron energy loss and chromatic aberration on the depth resolution of annular dark-field SCEM were studied through both experiments and computational simulations. The simulation results obtained by taking these two factors into consideration coincided well with those obtained by experiments, which proved that electron energy loss and chromatic aberration cause blurs at the overfocus sides of the Z-direction intensity profiles rather than degrade the depth resolution much. In addition, a deconvolution method using a simulated point spread function, which combined two Gaussian functions, was adopted to process the XZ-slice images obtained both from experiments and simulations. As a result, the blurs induced by energy loss and chromatic aberration were successfully removed, and there was also about 30% improvement in the depth resolution in deconvoluting the experimental XZ-slice image.

Cold nuclear matter effects on dijet productions in relativistic heavy-ion reactions at LHC

We investigate the cold nuclear matter (CNM) effects on dijet productions in high-energy nuclear collisions at LHC with the next-to-leading order perturbative QCD. The nuclear modifications for dijet angular distributions, dijet invariant mass spectra, dijet transverse momentum spectra and dijet momentum imbalance due to CNM effects are calculated by incorporating EPS, EKS, HKN and DS parametrization sets of parton distributions in nucleus. It is found that dijet angular distributions and dijet momentum imbalance are insensitive to the initial-state CNM effects and thus provide optimal tools to study the final-state hot QGP effects such as jet quenching. On the other hand, the invariant mass spectra and the transverse momentum spectra of dijet are generally enhanced in a wide region of the invariant mass or transverse momentum due to CNM effects with a feature opposite to the expected suppression because of the final-state parton energy loss effect in the QGP. The difference of EPS, EKS, HKN and DS parametrization sets of nuclear parton distribution functions is appreciable for dijet invariant mass spectra and transverse momentum spectra at p+Pb collisions, and becomes more pronounced for those at Pb+Pb reactions.

Effects of electronic energy loss on the behavior of Nd2Zr2O7 pyrochlore irradiated with swift heavy ions

Nd2Zr2O7 pyrochlore was irradiated with swift heavy ions in order to investigate the effects of electronic energy loss on the structural changes induced in this material. XRD and TEM results show that both pyrochlore–fluorite phase transformation and amorphization occur in Nd2Zr2O7. Ion tracks are thus composed of a mixture of anion-deficient fluorite phase and amorphous zones. A new phenomenological model (heterogeneous track overlap model – HTOM), which assumes a direct impact mechanism coupled with a single track overlap process to fit the transformation build-ups, is proposed to estimate the areas of the various track regions. The variation of electronic energy loss mainly influences the structure of ion tracks (and weakly their diameter), and essentially concerns the amount of amorphous phase versus the amount of fluorite counterpart.

Quenching of hadron and photon spectra in heavy-ion collisions from RHIC to LHC

The generic features of parton energy loss effects on the quenching of single hadron spectra in heavy-ion collisions are discussed, paying attention to the expected differences from RHIC to LHC. The need for precise baseline measurements in p–Pb collisions at the LHC is also emphasized. Finally, I briefly mention the production of prompt photons in heavy-ion collisions as well as some open questions.

Parton energy loss and modified beam quark distribution functions in Drell–Yan process in collisions

Within the framework of generalized collinear factorization in perturbative QCD (pQCD), we study the effect of initial multiple parton scattering and induced parton energy loss in Drell-Yan (DY) process in proton-nucleus collisions. We express the contribution from multiple parton scattering and induced gluon radiation to the DY dilepton spectra in terms of nuclear modified effective beam quark distribution functions. The modification depends on the quark transport parameter in nuclear medium. This is similar to the final-state multiple parton scattering in deeply inelastic scattering (DIS) off large nuclei and leads to the suppression of the Drell-Yan cross section in $p+A$ relative to $p+p$ collisions. With the value of quark transport parameter determined from the nuclear modification of single-inclusive DIS hadron spectra as measured by the HERMES experiment, we calculate DY spectra in $p+A$ collisions and find the nuclear suppression due to beam parton energy loss negligible at the Fermilab energy $E_{\rm lab}$=800 GeV in the kinematic region as covered by the E866 experiment. Most of the observed nuclear suppression of DY spectra in E866 experiment can be described well by parton shadowing in target nuclei as given by the EPS08 parameterization. The effect of beam parton energy loss, however, becomes significant for DY lepton pairs with large beam parton momentum fraction $x^{\prime}$ or small target parton momentum fraction $x$. We also predict the DY cross section in $p+A$ collisions at lower beam proton energy $E_{\rm lab}$=120 GeV and show significant suppression due to initial state parton energy loss at moderately large $x^{\prime}$ where the effect of parton shadowing is very small.

A possible determination of the quark radiation length in cold nuclear matter

We calculate the differential Drell–Yan production cross section in proton–nucleus collisions by including both next-to-leading order perturbative effects and effects of the nuclear medium. We demonstrate that dilepton production in fixed target experiments is an excellent tool to study initial-state parton energy loss in large nuclei and to accurately determine the stopping power of cold nuclear matter. We provide theoretical predictions for the attenuation of the Drell–Yan cross section at large values of Feynman xF and show that for low proton beam energies experimental measurements at Fermilabʼs E906 can clearly distinguish between nuclear shadowing and energy loss effects. If confirmed by data, our results may help determine the quark radiation length in cold nuclear matter X0∼10−13 m.

The dependence of J/ψ-nucleon inelastic cross section on the Feynman variable

By means of two typical sets of nuclear parton distribution functions, meanwhile taking account of the energy loss of the beam proton and the nuclear absorption of the charmonium states traversing the nuclear matter in the uniform framework of the Glauber model, a leading order phenomenological analysis is given in the color evaporation model of the E866 experimental data on J/ψ production differential cross section ratios RFe/Be(xF). It is shown that the energy loss effect of beam proton on RFe/Be(xF) is more important than the nuclear effects on parton distribution functions in the high Feynman variable xF region. It is found that the J/ψ-nucleon inelastic cross section depends on the Feynman variable xF and increases linearly with xF in the region xF > 0.2.

Three-hadron angular correlations in high-energy proton-proton and nucleus-nucleus collisions from perturbative QCD

We study three-hadron azimuthal angular correlations in high energy proton-proton and central nucleus-nucleus collisions at RHIC and LHC at mid-rapidity. We use the LO parton matrix elements for 2 \rightarrow 3 processes and include the effect of parton energy loss in the Quark-Gluon Plasma using the modified fragmentation function approach. For the case when the produced hadrons have either same or not too different momenta, we observe two away side peaks at 2pi/3 and 4pi/3. We consider the dependence of the angular correlations on energy loss parameters that have been used in studies of single inclusive hadron production at RHIC. Our results on the angular dependence of the cross section agree well with preliminary data by the PHENIX collaboration. We comment on the possible contribution of 2 \rightarrow 3 processes to di-hadron angular correlations and how a comparison of the two processes may help characterize the plasma further.

On the nuclear modification factor at RHIC and LHC

We show that pQCD factorization incorporated with pre-haronization energy-loss effect naturally leads to flatness of the nuclear modification factor R_{AA} for produced hadrons at high transverse momentum p_T. We consider two possible scenarios for the pre-hadronization: In scenario 1, the produced gluon propagates through dense QCD medium and loses energy. In scenario 2, all gluons first decay to quark-antiquark pairs and then each pair loses energy as propagating through the medium. We show that the estimates of the energy-loss in these two different models lead to very close values and is able to explain the suppression of high-p_T hadrons in nucleus-nucleus collisions at RHIC. We show that the onset of the flatness of R_{AA} for the produced hadron in central collisions at midrapidity is about p_T\approx 15 and 25 GeV at RHIC and the LHC energies, respectively. We show that the smallness (R_{AA}<0.5) and the high-p_T flatness of R_{AA} obtained from the k_T factorization supplemented with the Balitsky-Kovchegov (BK) equation is rather generic and it does not strongly depend on the details of the BK solutions. We show that energy-loss effect reduces the nuclear modification factor obtained from the k_T factorization about 30\div 50% at moderate p_T.

Numerical analysis of the effects of radiation heat transfer and ionization energy loss on the cavitation Bubbleʼs dynamics

A numerical scheme for simulating the acoustic and hydrodynamic cavitation was developed. Bubble instantaneous radius was obtained using Gilmore equation which considered the compressibility of the liquid. A uniform temperature was assumed for the inside gas during the collapse. Radiation heat transfer inside the bubble and the heat conduction to the bubble was considered. The numerical code was validated with the experimental data and a good correspondence was observed. The dynamics of hydrofoil cavitation bubble were also investigated. It was concluded that the thermal radiation heat transfer rate strongly depended on the cavitation number, initial bubble radius and hydrofoil angle of attack.

Measurements of di-jets in p+p and Au+Au in the STAR experiment

Jets are produced from hard scatterings in the early stages of heavy-ion collisions. It is expected that these high-p T partons travel through the hot and dense medium before fragmenting. Therefore they are expected to suffer energy loss in the QGP via gluon radiation or elastic collisions along their path. Measurements from full jet reconstruction help in the understanding of energy loss and its effect on the jet structure and energy profile. A data-driven characterization of the background in Au+Au is needed in order to compare the results to p+p. The large coverage of the STAR detector along with an online trigger also allows for reconstructing di-jets. Suitable selection of trigger jets allows for studying a subset of jets on the recoil side which are biased towards higher energy loss because of a larger, on average, in-medium path length traversed. Trigger jets are also used to study jet-hadron correlations as an independent measurement to assess the effect of energy loss on the recoil side. We present measurements of di-jets and jet-hadron correlations in the presence of reconstructed di-jets in Au+Au and p+p at 200 GeV in the STAR experiment.

The effect of high water temperatures on the allometric scaling effects of energy and protein starvation losses in juvenile barramundi, Lates calcarifer

This study was undertaken to examine the effects of high water temperatures on the allometric scaling effects of energy and protein starvation losses by juvenile barramundi, Lates calcarifer. The somatic energy and protein loss was examined in fish of varying sizes when starved for 24 or 25 days at temperatures ranging from 23 °C to 38 °C. The amount of energy and protein lost varied according to both size and temperature and was consistent with the function of a ⁎ W b , where a is a temperature dependent coefficient, W the animal's weight and b an exponent relating energy loss to live-weight. The coefficient for energy or protein loss varied and was described by a polynomial function, with a general increase from 23 °C to 32 °C, before a dramatic decline after 35 °C. In contrast, the exponent for energy loss was relatively constant between 23 °C and 35 °C, but showed a rapid increase at 38 °C. Both the coefficients and exponents of protein loss mirrored that of energy loss. Analysis of the protein and lipid contributions to energy loss shows that typically lipid loss accounts for the greater part of energy loss (~ 67%), but also shows that above 35 °C protein energy loss increases (from ~ 33% to ~ 39%) while the losses seen from lipid catabolism remain the same. These results show that one of the main nutritional issues associated with heat stress in fish is a dramatic increase in endogenous loss of protein.

Evolution and tailoring of plasmonic properties in Ag:ZrO2 nanocomposite films by swift heavy ion irradiation

Ag:ZrO2 nanocomposite films have been synthesized by a sol-gel dip coating process at room temperature, followed by irradiation using swift heavy ions. The effect of electronic energy loss and fluences on the evolution and consequently on the tailoring of plasmonic properties of films has been studied. The optical study exhibits that color of films converts from transparent in pristine form into shiny yellow when films are irradiated by 100 MeV Ag ions at a fluence of 3×1012 ions/cm2. However, irradiation by 120 MeV O ions up to the fluence of 1 × 1014 ions/cm2 does not induce any coloration in films. The coloration is attributed to the evolution of plasmonic feature resulting in a surface plasmon resonance (SPR) induced absorption peak in the visible region. Increase in fluence from 3 × 1012 to 6 × 1013 ions/cm2 of 100 MeV Ag ions induces a redshift in SPR induced peak position from 434 to 487 nm. Microstructural studies confirms the conversion of Ag2O3 (in pristine films) into cubic phase of metallic Ag and the increase of average size of particles with the increasing fluence up to 6 × 1013 ions/cm2. Further increase in fluence leads to the dissolution of Ag atoms in the ZrO2 matrix.

Effect of liquid-solid ratio on the morphology, structure, conductivity, and electromagnetic characteristics of iron particles

Using a ball-milling technique, polymorphous iron particles were prepared by changing only the liquid-solid ratio λ. Effects of λ on their morphology, structure, conductivity, and electromagnetic properties were studied. The results show that an increase of λ from 0 to 0.25 causes a nonlinear decrease of the conductivity in the ranges of 88.50–2.25 S cm−1 and a regular variation of the electromagnetic parameters, corresponding to the as-obtained iron particles. This is ascribed to a combination of the increased shape anisotropy and the decreased fresh surface with active atoms deriving from the weakened welding-on action and the enhanced micro-malleation action in the ball-milling process. Hereinto, the iron flakes formed at wet-milling with λ=0.08−0.25 have lower conductivity, higher permittivity and permeability, and more excellent absorption property compared with the irregular iron particles obtained at dry-milling with λ=0. It is a consequence of the synergistic effect of dielectric relaxation loss, exchange energy and conductance loss originating from the flake-shape structures. This indicates that the morphology, structure, conductivity, and electromagnetic properties of the products can be effectively controlled by changing λ.