The chiral magnetic effect (CME) in quantum chromodynamics (QCD) refers to a charge separation (an electric current) of chirality imbalanced quarks generated along an external strong magnetic field. ...The chirality imbalance results from interactions of quarks, under the approximate chiral symmetry restoration, with metastable local domains of gluon fields of non-zero topological charges out of QCD vacuum fluctuations. Those local domains violate the P and CP invariance, potentially offering a solution to the strong CP problem in explaining the magnitude of the matter–antimatter asymmetry in today’s universe. Relativistic heavy-ion collisions, with the likely creation of the high energy density quark–gluon plasma and restoration of the approximate chiral symmetry, and the possibly long-lived strong magnetic field, provide a unique opportunity to detect the CME. Early measurements of the CME-induced charge separation in heavy-ion collisions are dominated by physics backgrounds. Major efforts have been devoted to eliminate or reduce those backgrounds. We review those efforts, with a somewhat historical perspective, and focus on the recent innovative experimental undertakings in the search for the CME in heavy-ion collisions.
Advanced solar energy utilization technology requires high-grade energy to achieve the most efficient application with compact size and least capital investment recovery period. Concentrated solar ...power (CSP) technology has the capability to meet thermal energy and electrical demands. Benefits of using CSP technology with parabolic trough collector (PTC) system include promising cost-effective investment, mature technology, and ease of combining with fossil fuels or other renewable energy sources. This review first covered the theoretical framework of CSP technology with PTC system. Next, the detailed derivation process of the maximum theoretical concentration ratio of the PTC was initially given. Multiple types of heat transfer fluids in tube receivers were reviewed to present the capability of application. Moreover, recent developments on heat transfer enhancement methods for CSP technology with PTC system were highlighted. As the rupture of glass covers was frequently observed during application, methods of thermal deformation restrain for tube receivers were reviewed as well. Commercial CSP plants worldwide with PTC system were presented, including those that are in operation, under construction, and announced. Finally, possible further developments of CSP plants with PTC system were outlined. Besides, suggestions for future research and application guidance were also illustrated.
•Symmetric outward convex corrugated tube is introduced as the metal tube of PTR.•Effective heat transfer coefficient can be increased up to 8.4% when SCPTR is used.•Regression equation is put ...forward for heat transfer coefficient and Nusselt number.•Corrugated tube can enhance thermal performance and reliability of PTR effectively.
A symmetric outward convex corrugated tube design is introduced for parabolic trough receivers with the aim of increasing their heat transfer performance and reliability. An optical–thermal–structural sequential coupled method was developed to analyze the heat transfer performance and thermal deformation of the glass cover and metal tube of the parabolic trough receiver. The developed coupled method has been validated with experimental results conducted in the DISS test facility in Spain. The numerical results indicated that the introduction of a symmetric outward convex corrugated tube design for the metal tube of the parabolic trough receiver can effectively enhance the heat transfer performance and decrease the thermal strain. The effective heat transfer coefficient can be increased up to 8.4% and the maximum thermal strain of metal tube can be decreased up to 13.1% when symmetric outward convex corrugated tube is used at Re=81728, p/D=4.3. In addition, regression correlations are put forward in order to find an effective heat transfer coefficient and effective Nusselt number for the fluid flow in the parabolic trough receiver.
We use a coalescence model to generate f0(980) particles for four configurations: ss¯ meson, uu¯ss¯ tetraquark, KK¯ molecule, and uu¯ p-wave state. The phase-space information of the coalescing ...constituents is taken from a multi-phase transport (AMPT) simulation of proton-proton (pp) and proton-lead (pPb) collisions at the LHC. It is shown that the transverse momentum spectra and production yields of f0(980) differ significantly among the configurations. It is suggested that the pT spectra of the f0(980) compared to those of other hadrons (such as pion) and the ratio of the f0(980)pT spectra in pPb over pp collisions can be exploited to tell the configuration of the f0(980).
With the aim to increase the overall heat transfer performance and reliability of tube receiver for parabolic trough solar collector system, asymmetric outward convex corrugated tube is introduced as ...the metal tube of parabolic trough receiver. An optical-thermal-structural sequential coupled method was developed to study the heat transfer performance and thermal strain of tube receiver for parabolic trough solar collector system. Heat transfer performance and thermal strain comparisons between conventional tube receiver and asymmetric outward convex corrugated tube receiver are conducted. The researches indicated that the usage of asymmetric outward convex corrugated tube as receiver can enhance the heat transfer performance and reduce the thermal strain effectively. By using asymmetric outward convex corrugated tube as receiver, the maximum enhancement of overall heat transfer performance factor is 148% and the maximum restrain of von-Mises thermal strain is 26.8%.
•Asymmetric outward convex corrugated tube receiver is introduced as the metal tube of PTR.•Overall heat transfer performance factor is increased up to 148% by using ACPTR.•Regression equations are put forward for Nusselt number and Fanning friction factor.•Asymmetric outward convex corrugated tube can increase reliability of PTR effectively.
Radiative cooling is a passive means of cooling that does not require the consumption of additional energy and has broad application potential. While experimental spectral measurements have been ...conducted, the daylighting of buildings, photovoltaic (PV) cells, and vehicles has seldom been considered. Here, we use spectrum-selective coatings to resolve the competing demands of daylighting (or appearance) and radiative cooling. A simple liquid blade-coating method that was inexpensive, convenient, and scalable was used to achieve radiative cooling with ultrahigh transmittance in visible light and excellent cooling performance. Resonant polar dielectric SiO2 microparticles with optimized volumetric fractions and diameters were randomly mixed into an acrylic resin and manually bladed at room temperature with natural evaporation drying. Spectrometry results showed that a mean visible light transmittance >91.3% was achieved, which was much higher than reported in previous studies; a mean emittance >93.7% within the “atmospheric window” was also reached. Over four days testing of a silver-plated aluminum sheet in a populous area at sea level, we achieved a maximum sub-ambient decrease in temperature of ~8.7 °C and a maximum cooling power of 108.49 W/m2.
Figure Radiative cooling blade coating with ultrahigh visible light transmittance and emission within an “atmospheric window”. Display omitted
•Competing demands of daylighting (or appearance) and radiative cooling is resolved.•Low cost liquid blade-coating method is developed for radiative cooling.•Visible light transmittance>91.3% and emittance>93.7% in atmospheric window.•Over four days testing, a maximum sub-ambient decrease in temperature of ~8.7 °C.•Over four days testing, the maximum radiative cooling power is 108.49 W/m2
Nanofluid-based spectral splitting concentrating photovoltaic thermal (CPV/T) system enables photovoltaic (CPV) cells and thermal absorbers to operate at different temperatures and realizes the ...utilization of full-spectrum sunlight. It is important to find one kind of low cost nanofluid that can be applied to nanofluid-based spectral splitting CPV/T system. In this study, the feasibility of using cost-effective glycol-ZnO nanofluid in spectral splitting CPV/T system was experimentally verified. A two-axis sun-tracking nanofluid-based spectral splitting CPV/T system was designed and fabricated. The solar energy conversion efficiency correlation coefficient was utilized to compare the thermodynamic performance of glycol-ZnO nanofluid-based spectral splitting CPV/T system with those of water-polypyrrole and water-Ag-SiO2 nanofluid-based spectral splitting CPV/T system. The effects of ZnO nanoparticles concentration in glycol-ZnO nanofluid on thermal and electrical performances were investigated. The cost comparisons of different types of nanoparticles were also conducted. The results indicated that the correlation coefficient of glycol-ZnO nanofluid-based spectral splitting CPV/T system was 0.218 and 0.05 higher than those of water-polypyrrole and water-Ag-SiO2 nanofluid-based spectral splitting CPV/T system, respectively. The cost of ZnO nanoparticles was 0.13%, 0.08% and 0.17% of cost of Au, Ag and polypyrrole nanoparticles, respectively.
•. Using cost-effective ZnO nanofluid in splitting CPVT was experimentally verified.•. ZnO nanofluid has better performance in CPVT than polypyrrole & Ag–SiO2 nanofluid.•. ZnO nanofluid has big cost advantage than reported nanofluid in CPVT system.
•Effects of glass cover on heat flux distribution are analyzed by MCRT method.•Heat flux changes slightly when sunlight pass through GC with circular cross section.•Glass cover with elliptic–circular ...cross section is put forward.•The new shape of glass cover can decrease heat flux distribution gradient.
A solar receiver is designed for operation under extremely uneven heat flux distribution, cyclic weather, and cloud transient cycle conditions, which can induce large thermal stress and even receiver failure. In this study, the effects of a glass cover (GC) on heat flux distribution are analyzed by Monte Carlo Ray Tracing (MCRT) method. In order to minimize the heat flux gradient, which in turn can reduce the thermal stress of tube receiver, a GC with elliptic–circular cross section is proposed in this study. The effects of refractivity and characteristic parameters on the heat flux distribution are also investigated. The numerical results indicate that the magnitude and distribution of heat flux are affected only slightly when concentrated sunlight passes through the GC with circular cross section, and adopting a GC with elliptic–circular cross section for the tube receiver can effectively decrease the heat flux gradient, the peak heat flux reduction is up to 32.3%.
The effects of neutron skin on the multiplicity (Nch) and eccentricity (ϵ2) in relativistic 4496Ru+4496Ru and 4096Zr+4096Zr collisions at sNN=200 GeV are investigated with the Trento model. It is ...found that the Ru+Ru/Zr+Zr ratios of the Nch distributions and ϵ2 in mid-central collisions are exquisitely sensitive to the neutron skin type (skin vs. halo). The state-of-the-art calculations by energy density functional theory (DFT) favor the halo-type neutron skin and can soon be confronted by experimental data. It is demonstrated that the halo-type density can serve as a good surrogate for the DFT density, and thus can be efficiently employed to probe nuclear deformities by using elliptic flow data in central collisions. We provide hereby a proof-of-principle venue to simultaneously determine the neutron skin type, thickness, and nuclear deformity.
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