Cross‐linked polyethylene (XLPE) is notable for its use as power cable insulation. Its longevity is limited by space charge buildup linked to impurities such as the byproducts left behind by the ...cross‐linking agent dicumyl peroxide (DCP). The goal of this work is to determine the impacts of these byproducts on charge trapping and detrapping in XLPE using the thermally stimulated depolarization current technique. XLPE with byproducts has one source of trapped charge, which originates from the byproducts. XLPE that was thermally treated via degassing exhibits two other sources of trapped charge, which are charge injection and dipolar relaxations. Oxidation from degassing was shown to control the trapping from these sources, which is useful knowledge for processing this material prior to its use. Reintroducing acetophenone, one of the major byproducts of DCP, suppresses those two peaks once more, showing that it controls the overall space charge buildup characteristics in XLPE.
The electrical properties of cross‐linked polyethylene (XLPE) are relevant for power cable applications. Charge trapping and detrapping in XLPE is examined in this work using the thermally stimulated depolarization technique. Under the as‐received condition, there is one main source of trapped charge–cross‐linking byproducts such as acetophenone (ACP) and water. Thermal treatments like degassing alter the resulting thermally stimulated depolarization current spectra by removing ACP and leaving behind water, thus revealing the intrinsic trapping characteristics of XLPE.
A hernia is a pathological condition caused by a defect or opening in the muscle wall, which leads to organs pushing through the opening or defect. Hernia recurrence, seroma, persistent pain, tissue ...adhesions, and wound infection are common complications following hernia repair surgery. Infection after hernia mesh implantation is the third major complication leading to hernia recurrence. In order to reduce the incidence of late infections, we developed a polypropylene mesh with antibacterial properties. In this study, knitted polypropylene meshes were exposed to radio-frequency plasma to activate their surfaces. The antibacterial monomer diallyldimethylammonium chloride (DADMAC) was then grafted onto the mesh surface using pentaerythritol tetraacrylate as the cross-linker since it is able to engage all four functional groups to form a high-density cross-linked network. The subsequent antibacterial performance showed a 2.9 log reduction toward Staphylococcus aureus and a 0.9 log reduction for Escherichia coli.
A fully integrated phase-shifted (PS) transmitter is presented in this paper. The PS transmitter employs switching power amplifiers, operates without mixers, and provides an intermodulation ...distortion-free output spectrum, making it a suitable choice for mobile communication systems. The RF blocks of the PS transmitter include a local oscillator, phase shifters, and switching class-F power amplifiers with wide-band matching networks. The PS transmitter is implemented in a standard single-polysilicon, six-metal 0.18-/spl mu/m CMOS technology and occupies an area of 3 mm/sup 2/. It operates from a 1-V supply and provides better than 42 dBc adjacent channel power ratio with an output bandwidth of 50 MHz at 8 GHz. The PS transmitter RF front-end provides 22 dBm of average output power with a 38% average power added efficiency.
G. M. Whitesides and co‐workers describe, on page 2446, the design and fabrication of electrically controlled paper actuators made from paper, conducting polymer, and adhesive tape. The central ...element of the actuators is a porous conducting path providing electrothermal heating that changes the moisture content of the paper and causes actuation. These simple and inexpensive devices can achieve different types of motion such as bending and accordion‐type motion.
We present an aeroacoustic shape optimization framework that relies on high-order Flux Reconstruction (FR) spatial discretization, the gradient-free Mesh Adaptive Direct Search (MADS) optimization ...algorithm, and Large Eddy Simulation (LES). Our parallel implementation ensures that the runtime of each optimization iteration remains consistent, irrespective of the number of design parameters involved in the optimization problem, provided sufficient resources are available. This eliminates the dependence of the runtime of gradient-free algorithms on the number of design variables. The objective is to minimize Sound Pressure Level (SPL) at a near-field observer by computing it directly from the flow field. We evaluate this framework across three different problems. First, an open deep cavity is considered at a free-stream Mach number of \(M=0.15\) and Reynolds number of \(Re=1500\) based on the cavity's depth, reducing the SPL by \(12.86dB\). Next, we optimized tandem cylinders at \(Re=1000\) and \(M=0.2\), achieving over \(11dB\) noise reduction by optimizing cylinder spacing and diameter ratio. Lastly, a baseline NACA0012 airfoil is optimized at \(Re=23000\) and \(M=0.2\). The shape of the airfoil is optimized to generate a new 4-digit NACA airfoil at an appropriate angle of attack to minimize the SPL while ensuring the baseline time-averaged lift coefficient is maintained and prevent any increase in the baseline time-averaged drag coefficient. The SPL is reduced by \(5.66dB\) while the mean drag coefficient is reduced by more than \(7\%\). These results highlight the feasibility and effectiveness of our aeroacoustic shape optimization framework.
The group-contribution, lattice-fluid (GCLF) equation of state (EoS) is now more than 10 years old. The primary objective of our effort has been to develop a predictive model for the phase equilibria ...in polymer-solvent systems. The model has been developed by introducing group-contribution to the Panayiotou-Vera EoS. This paper reviews and updates the application of this approach along with its shortcomings. This EoS has been applied to prediction of the density of pure polymers, VLE of vapors, supercritical gas solubility, LLE, solubility parameters, and glass transition temperatures. Homopolymers and random copolymers can be successfully treated. The key features of this model are that it is purely predictive based only on the molecular structure of the molecules, and it is able to describe the pressure as well as temperature and composition effects because it is based on an EoS.
Antiserum raised against
Rhodnius prolixus perimicrovillar membranes (PMM) and midgut tissue interfered with the midgut structural organization and reduced the development of
Trypanosoma cruzi in the
...R. prolixus insect vector. SDS–PAGE and Western blot analyses confirmed the specific recognition of midgut proteins by the antibody. Feeding, mortality, molt, and oviposition of the insects were unaffected by feeding with the antiserum. However, the eclosion of the eggs were reduced from
R. prolixus females treated with antiserum. Additionally, in vivo evaluation showed that after oral treatment with the antiserum, the intensity of infection with the Dm-28c clone of
T. cruzi decreased in the digestive tract of fifth-instar nymphs and in the excretions of
R. prolixus adults. These results suggest that the changes observed in the PMM organization in the posterior midgut of
R. prolixus may not be important for triatomine survival but the antiserum acts as a transmission-reduction vaccine able to induce significant decreases in
T. cruzi infection in the vector.
We investigate the phenomenon of magnomechanically induced grating (MMIG) within a cavity magnomechanical system, comprising magnons (spins in a ferromagnet, such as yttrium iron garnet), cavity ...microwave photons, and phonons \textit{J. Li, S.-Y. Zhu, and G. S. Agarwal, Phys. Rev. Lett. \textbf{121}, 203601 (2018)}. By applying an external standing wave control, we observe modifications in the transmission profile of a probe light beam, signifying the presence of MMIG. Through numerical analysis, we explore the diffraction intensities of the probe field, examining the impact of interactions between cavity magnons, magnon-phonon interactions, standing wave field strength, and interaction length. MMIG systems leverage the unique properties of magnons, and collective spin excitations with attributes like long coherence times and spin-wave propagation. These distinctive features can be harnessed in MMIG systems for innovative applications in information storage, retrieval, and quantum memories, offering various orders of diffraction grating.
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