Metal-Coated Defect-Core Photonic Crystal Fiber for THz Propagation

Modal solutions for metal-coated defect-core photonic crystal fiber (PCF) with a central air-hole have been obtained by using a full-vectorial finite element method to model the guidance of THz waves. It has been shown that the surface plasmon modes can couple with the defect-core PCF mode to form supermodes, with potential for sensing applications

Drug-Induced Liver Injury: Pattern Recognition and Future Directions

Drug-induced liver injury (DILI) remains a significant clinical challenge and is the leading cause of acute liver failure in most countries. An aging population that uses more medications, a constant influx of newly developed drugs and a growing risk from unfamiliar herbal and dietary supplements will make DILI an increasing part of clinical practice. Currently, the most effective strategy for disease management is rapid identification, withholding the inciting agents, supportive care and having a firm understanding of the expected natural history. There are resources available to aid the clinician, including a new online “textbook” as well as causality assessment tools, but a heightened awareness of risk and the disease’s varying phenotypes and good history-taking remain cornerstones to diagnosis. Looking ahead, growing registries of cases, pharmacoepidemiology studies and translational research into the mechanisms of injury may produce better diagnostic tools, markers for risk and disease, and prevention and therapeutics

Smart and robust electrospun fabrics of piezoelectric polymer nanocomposite for self-powering electronic textiles

The present work designs a piezoelectric nanogenerator (PENG) based on the electrospun nanofibers of the piezoelectric polymer, polyvinylidene fluoride hexafluoropropylene (PVDF-HFP), by uniformly drawing the spun membranes containing cellulose nanocrystals (CNC, 2 wt%) and the Fe-doped nano ZnO (2 wt%). The hybrid nanocomposite fibers were made in double layers, with CNC/PVDF-HFP composite on one side and the Fe-doped ZnO/PVDF-HFP on the other side. This ferroelectric polymer composite exhibited maximum peak-to-peak output voltage of 12 V with a current density, 1.9 ?Acm?2, which are respectively higher by 60 and 2.3 times compared to the neat polymer fibers. The PENG is tested for its energy harvesting ability by exposing it to different environments such as ultrasound vibrations and human body movements during hand tapping, elbow movements and by attaching with the textile fabrics. While the finger tapping generated peak-to-peak output voltage of 6.5 V, elbow movements resulted in 5.5 V generation. In all sorts of movements, the nanogenerator shows good output performance indicating its compatibility with textile materials. The mechanical properties, breakdown strength and dielectric properties of the material are also in accordance with its possible applications in wearable electronic textiles. - 2019 The AuthorsThis publication is made possible by NPRP grant 6-282-2-119 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

On the Tapping Mode Measurement for Young’s Modulus of Nanocrystalline Metal Coatings

Young’s modulus of nanocrystalline metal coatings is measured using the oscillating, that is, tapping, mode of a cantilever with a diamond tip. The resonant frequency of the cantilever changes when the diamond tip comes in contact with a sample surface. A Hertz-contact-based model is further developed using higher-order terms in a Taylor series expansion to determine a relationship between the reduced elastic modulus and the shift in the resonant frequency of the cantilever during elastic contact between the diamond tip and sample surface. The tapping mode technique can be used to accurately determine Young’s modulus that corresponds with the crystalline orientation of the sample surface as demonstrated for nanocrystalline nickel, vanadium, and tantalum coatings

Robust hydrophobic surfaces from suspension HVOF thermal sprayed rare-earth oxide ceramics coatings

This study has presented an efficient coating method, namely suspension high velocity oxy-fuel (SHVOF) thermal spraying, to produce large super-hydrophobic ceramic surfaces with a unique micro- and nano-scale hierarchical structures to mimic natural super-hydrophobic surfaces. CeO2 was selected as coatings material, one of a group of rare-earth oxide (REO) ceramics that have recently been found to exhibit intrinsic hydrophobicity, even after exposure to high temperatures and abrasive wear. Robust hydrophobic REO ceramic surfaces were obtained from the deposition of thin CeO2 coatings (3–5 μm) using an aqueous suspension with a solid concentration of 30 wt.% sub-micron CeO2 particles (50–200 nm) on a selection of metallic substrates. It was found that the coatings’ hydrophobicity, microstructure, surface morphology, and deposition efficiency were all determined by the metallic substrates underneath. More importantly, it was demonstrated that the near super-hydrophobicity of SHVOF sprayed CeO2 coatings was achieved not only by the intrinsic hydrophobicity of REO but also their unique hierarchically structure. In addition, the coatings’ surface hydrophobicity was sensitive to the O/Ce ratio, which could explain the ‘delayed’ hydrophobicity of REO coatings

Higher Order Lateral Mode Suppression Schemes for Edge Emitting Terahertz Quantum Cascade Laser Waveguides

The modal performance of a slot-clad metal-metal waveguide for terahertz quantum cascade lasers (QCLs) is elucidated in this study. Terahertz QCLs, based on metal-metal waveguides having a large ridge width, are susceptible to lase with higher order lateral modes, which may produce poor quality beams and can lead to detrimental consequences for certain applications. By comparing the modal performance of the slot-clad waveguide with previously reported designs, it has been shown that the slot-clad metal-metal waveguide can significantly enhance the degree of suppression of higher order lateral modes

The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817

The historic detection of gravitational waves from a binary neutron star merger (GW170817) and its electromagnetic counterpart led to the first accurate (sub-arcsecond) localization of a gravitational-wave event. The transient was found to be $\sim$10" from the nucleus of the S0 galaxy NGC 4993. We report here the luminosity distance to this galaxy using two independent methods. (1) Based on our MUSE/VLT measurement of the heliocentric redshift ($z_{\rm helio}=0.009783\pm0.000023$) we infer the systemic recession velocity of the NGC 4993 group of galaxies in the cosmic microwave background (CMB) frame to be $v_{\rm CMB}=3231 \pm 53$ km s$^{-1}$. Using constrained cosmological simulations we estimate the line-of-sight peculiar velocity to be $v_{\rm pec}=307 \pm 230$ km s$^{-1}$, resulting in a cosmic velocity of $v_{\rm cosmic}=2924 \pm 236$ km s$^{-1}$ ($z_{\rm cosmic}=0.00980\pm 0.00079$) and a distance of $D_z=40.4\pm 3.4$ Mpc assuming a local Hubble constant of $H_0=73.24\pm 1.74$ km s$^{-1}$ Mpc$^{-1}$. (2) Using Hubble Space Telescope measurements of the effective radius (15.5" $\pm$ 1.5") and contained intensity and MUSE/VLT measurements of the velocity dispersion, we place NGC 4993 on the Fundamental Plane (FP) of E and S0 galaxies. Comparing to a frame of 10 clusters containing 226 galaxies, this yields a distance estimate of $D_{\rm FP}=44.0\pm 7.5$ Mpc. The combined redshift and FP distance is $D_{\rm NGC 4993}= 41.0\pm 3.1$ Mpc. This 'electromagnetic' distance estimate is consistent with the independent measurement of the distance to GW170817 as obtained from the gravitational-wave signal ($D_{\rm GW}= 43.8^{+2.9}_{-6.9}$ Mpc) and confirms that GW170817 occurred in NGC 4993.Comment: 9 pages, 5 figure