Energy extraction from rotating regular black hole via magnetic reconnection

Recently, it has been demonstrated that magnetic reconnection processes in the ergosphere of a Kerr black hole can provide us with a promising mechanism for extracting the rotational energy from it. In this paper, we study the energy extraction from the the newly proposed rotating regular black holes via this magnetic reconnection mechanism. This novel rotating regular black hole has an exponential convergence factor $e^{-k/r}$ on the mass term characterized by the regular parameter $k$ in the exponent. We explore the effects of this regular parameter on the magnetic reconnection as well as other critical parameters determining the magnetic reconnection process. The parameter spaces allowing energy extraction to occur are investigated. The power, efficiency and the power ratio to the Blandford-Znajek mechanism are studied. The results show that the regularity of the rotating black hole has significant effects on the energy extraction via the magnetic reconnection mechanism.Comment: 8 pages, 9 figure

Dispersion of Short- and Medium-Chain Chlorinated Paraffins (CPs) from a CP Production Plant to the Surrounding Surface Soils and Coniferous Leaves

Chlorinated paraffin (CP) production is one important emission source for short- and medium-chain CPs (SCCPs and MCCPs) in the environment. In this study, 48 CP congener groups were measured in the surface soils and coniferous leaves collected from the inner and surrounding environment of a CP production plant that has been in operation for more than 30 years to investigate the dispersion and deposition behavior of SCCPs and MCCPs. The average concentrations of the sum of SCCPs and MCCPs in the in-plant coniferous leaves and surface soils were 4548.7 ng g^–1 dry weight (dw) and 3481.8 ng g^–1 dw, which were 2-fold and 10-fold higher than those in the surrounding environment, respectively. The Gaussian air pollution model explained the spatial distribution of CPs in the coniferous leaves, whereas the dispersion of CPs to the surrounding surface soils fits the Boltzmann equation well. Significant fractionation effect was observed for the atmospheric dispersion of CPs from the production plant. CP congener groups with higher octanol–air partitioning coefficients (<i>K</i>_OA) were more predominant in the in-plant environment, whereas the ones with lower <i>K</i>_OA values had the elevated proportion in the surrounding environment. A radius of approximately 4 km from the CP production plant was influenced by the atmospheric dispersion and deposition of CPs

Yohimbine promotes cardiac NE release and prevents LPS-induced cardiac dysfunction via blockade of presynaptic α2A-adrenergic receptor.

Myocardial depression is an important contributor to mortality in sepsis. We have recently demonstrated that α2-adrenoceptor (AR) antagonist, yohimbine (YHB), attenuates lipopolysaccharide (LPS)-induced myocardial depression. However, the mechanisms for this action of YHB are unclear. Here, we demonstrated that YHB decreased nitric oxide (NO) and tumor necrosis factor-alpha (TNF-α) levels in the myocardium and plasma, attenuated cardiac and hepatic dysfunction, but not kidney and lung injuries in endotoxemic mice. Immunohistochemical analysis revealed that cardiac α2A-AR was mostly located in sympathetic nerve presynaptic membrane; YHB decreased cardiac α2A-AR level and promoted cardiac norepinephrine (NE) release in endotoxemic mice. Reserpine that exhausted cardiac NE without markedly decreasing plasma NE level abrogated the inhibitory effects of YHB on cardiac TNF-α and iNOS expression as well as cardiac dysfunction, but not the suppressive effects of YHB on plasma TNF-α and NO elevation in LPS-challenged mice. Furthermore, both reserpine and YHB significantly inhibited LPS-induced myocardial apoptosis. α1-AR, β2-AR, but not β1-AR antagonists reversed the inhibitory effect of YHB on LPS-stimulated myocardial apoptosis. However, β1-AR antagonist attenuated LPS-caused cardiomyocyte apoptosis, partly abolished the protective effect of YHB on the left ventricular ejection fraction in endotoxemic mice. Altogether, these findings indicate that YHB attenuates LPS-induced cardiac dysfunction, at least in part, through blocking presynaptic α2A-AR and thus increasing cardiac NE release. YHB-elevated cardiac NE improves cardiac function via suppressing cardiac iNOS and TNF-α expression, activating β1-AR and inhibiting cardiomyocyte apoptosis through α1- and β2-AR in endotoxemic mice. However, cardiac β1-AR activation promotes LPS-induced cardiomyocyte apoptosis

Concentrations of short- and medium-chain chlorinated paraffins in indoor dusts from malls in China: Implications for human exposure

Levels and distribution of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) were measured in indoor dusts from malls in China. The concentrations of SCCPs and MCCPs in dustfalls from a building material mall ranged from 6.0 to 361.4 mu g g(-1) and from 5.0 to 285.9 mu g g(-1), respectively. Much heavier contamination was found in central air conditioner filter (CACF) dusts from a newly opened shopping mall, with SCCP concentrations of 114.7-707.0 mu g g(-1) and MCCP concentrations of 89.0 -1082.9 mu g g(-1). The C-13- and C-14-CP5 were the dominant congeners, while the Cl-7 and Cl-8 groups were the major chlorine congeners in both kinds of dust samples. Significant correlation relationships (p <= 0.05) were found between ESCCPs and EMCCPs in CACF dusts and dustfalls. Varied exposure pathways including dust ingestion and dermal permeation have been evaluated. The average daily exposure doses of SCCPs and MCCPs for the adult in CACF dusts and dustfalls were estimated to be 0.394 and 0.150 mu g kg(-1) day(-1), respectively. The toddler had higher exposure risks with 5.918 and 2.658 mu g kg(-1) day(-1) in the shopping and building material malls, respectively. Dermal permeation was the predominated exposure pathway for the adult, while dust ingestion was suggested to be more important for the toddler due to hand-to-mouth contact. (C) 2017 Elsevier Ltd. All rights reserved

A Thermal Tuning Meta-Duplex-Lens (MDL): Design and Characterization

Multifunctional metasurfaces play an important role in the development of integrated optical paths. However, some of the realizations of current multifunctional metasurface devices depend on polarization selectivity, and others change the polarization state of the outgoing light. Here, based on vanadium dioxide (VO2) phase change material, a strategy to design a meta-duplex-lens (MDL) is proposed and numerical simulation calculations demonstrate that at low temperature (about 300 K), VO2 behaves as a dielectric so that the MDL can act as a transmission lens (transmission efficiency of 87.6%). Conversely, when VO2 enters the metallic state (about 355 K), the MDL has the ability to reflect and polymerize electromagnetic waves and works as a reflection lens (reflection efficiency of 85.1%). The dielectric waveguide and gap-surface plasmon (GSP) theories are used in transmission and reflection directions, respectively. In order to satisfy the coverage of the phase gradient in the range of 2&pi; in both cases, we set the antenna as a nanopillar with a high aspect ratio. It is notable that, via symmetrical antennas acting in concert with VO2 phase change material, the polarization states of both the incident light and the outgoing light are not changed. This reversible tuning will play a significant role in the fields of imaging, optical storage devices, communication, sensors, etc

Release and Gas-Particle Partitioning Behaviors of Short-Chain Chlorinated Paraffins (SCCPs) During the Thermal Treatment of Polyvinyl Chloride Flooring

Chlorinated paraffin (CP) mixture is a common additive in polyvinyl chloride (PVC) products as a plasticizer and flame retardant. During the PVC plastic life cycle, intentional or incidental thermal processes inevitably cause an abrupt release of short-chain CPs (SCCPs). In this study, the thermal processing of PVC plastics was simulated by heating PVC flooring at 100–200 °C in a chamber. The 1 h thermal treatment caused the release of 1.9–10.7% of the embedded SCCPs. A developed emission model indicated that SCCP release was mainly controlled by material–gas partitioning at 100 °C. However, release control tended to be subjected to material-phase diffusion above 150 °C, especially for SCCP congeners with shorter carbon-chain lengths. A cascade impactor (NanoMoudi) was used to collect particles of different sizes and gas-phase SCCPs. The elevated temperature resulted in a higher partition of SCCPs from the gas-phase to particle-phase. SCCPs were not strongly inclined to form aerosol particles by nucleation, and less present in the Aitken mode particles. Junge-Pankow adsorption model well fitted the partitioning of SCCPs between the gas-phase and accumulation mode particles. Inhalation exposure estimation indicated that PVC processing and recycling workers could face a considerably high risk for exposure to SCCPs

Electrically-Driven Zoom Metalens Based on Dynamically Controlling the Phase of Barium Titanate (BTO) Column Antennas

The zoom metalens has been a research hotspot for metasurfaces in recent years. There are currently a variety of zoom methods, including dual metalenses, micro-electromechanical system metalenses, polydimethylsiloxane metalenses and Alvarez metalenses. However, for most metalenses, zooming is achieved by manipulating the relative displacement of two or more metasurfaces. Therefore, these methods seem inadequate when faced with more precise zooming requirements, and the precise control of the phase distribution cannot be achieved. In this paper, we innovatively propose an electrically-driven zoom metalens (EZM) of one-dimensional based on dynamically controlling barium titanate (BaTiO3, BTO) antennas. Using the electro-optic effect of BTO crystals, we can apply a voltage to change the refractive index of BTO nanopillars (n = 2.4–3.6), thereby accurately controlling the phase distribution of column antennas. The proposed EZM can achieve 5× zoom (f = 10–50 μm), with advantages, such as high-speed optical amplitude modulation, ultra-compactness, flexibility and replicability. It can be applied in fields that require ultra-compact beam focusing, zoom imaging, and microscopic measuring

Analysis of the virulence, infection process, and extracellular enzyme activities of Aspergillus nomius against the Asian corn borer, Ostrinia furnacalis guenée (Lepidoptera: Crambidae)

ABSTRACTThe control of Ostrinia furnacalis, a major pest of maize in Xinjiang, is challenging owing to the occurrence of resistant individuals. Entomopathogenic fungi (EPF) are natural insect regulators used as substitutes for synthetic chemical insecticides. The fungus Aspergillus nomius is highly pathogenic to O. furnacalis; however, its virulence characteristics have not been identified. This study aimed to analyse the lethal efficacy, mode of infection on the cuticle, and extracellular enzyme activity of A. nomius against O. furnacalis. We found that the mortality and mycosis of O. furnacalis were dose-dependent when exposed to A. nomius and varied at different life stages. The egg-hatching and adult emergence rates decreased with an increase in conidial suspension. The highest mortality (83.33%, 7 d post-infection [DPI]) and mycosis (74.33%, 7 DPI) and the lowest mortality response (8.52 × 103 conidia mL−1) and median lethal time (4.91 d) occurred in the 3rd instar larvae of O. furnacalis. Scanning electron microscopy indicated that numerous conidia germination and infection structure formation may have contributed to the high pathogenicity of A. nomius against O. furnacalis. There were significant correlations between O. furnacalis mortality and the activities of extracellular protease, lipase, and chitinase of A. nomius. This study revealed the infection process of the highly pathogenic A. nomius against O. furnacalis, providing a theoretical basis and reference for strain improvement and field application of EPF