Power control optimization of a new contactless piezoelectric harvester

In this study, we propose an optimization scheme for the control of a piezoelectric wind energy harvester. The harvester is constructed by a blade in front and a magnet in the rear in order to sustain a magnetic repulsion by another magnet located on the stable harvester body in a contactless manner. For such a new harvester, the control scheme is missing in the literature in the sense that the harvester is new and an overall optimization study is required for such a device. In that context, the optimization has been realized by using a new current control law based on the harvester piezoelectric terminal voltage and the layer bending. The proposed control law can impose a second order linear dynamics although the magnetic effects can yield to nonlinear magnetic force relation. In order to improve the new control strategy, a Particle Swarm Optimization algorithm (PSO) has been applied, since there is a nonlinear dependency among the control parameters, the collected energy and the bending force mean values. According to results, the captured electrical power has a high increasing trend with respect to the only-voltage-based (OVB) control as the current study proves. On the contrary, the artifact of the method is that the obtained power is too low to increase the mean bending forces and it requires much complicated control system.     

Diffusion characteristics of vinyl chloride from PVC in slurry phase

The porous nature of poly(vinyl chloride) (PVC) brings along the problem of residual vinyl chloride in the final product. Stripping techniques are developed to eliminate vinyl chloride to the desired levels. After a certain extent of monomer removal, the stripping rate of vinyl chloride is limited by diffusion. Therefore, the diffusion characteristics of vinyl chloride from PVC slurries was investigated. Stripping was carried out at the boiling point of water where the generated steam was used as a carrier substance. The boiling point of water was changed by elevating the pressures. The dependence of diffusion on concentration is put forward and the activation energy of diffusion was calculated.     

Effects of annealing on the structural and magnetic properties of flame spray pyrolyzed MnFe2O4 nanoparticles

In this study, manganese ferrite (MnFe₂O₄) nanoparticles were produced through flame spray pyrolysis (FSP). To investigate the effects of heat treatment, the nanoparticles were annealed between 400 and 650°C for 4 h in air in a comparative manner. The structural, chemical, morphological, and magnetic properties of the nanoparticles were evaluated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), dynamic light scattering (DLS), and vibrating sample magnetometry (VSM), respectively. The XRD results showed that the nanoparticles synthesized by the FSP method exhibited the MnFe₂O₄ spinel ferrite structure. The annealing process led to the decomposition of MnFe₂O₄ into various phases. According to the morphological analysis, the as-synthesized particles were hemispherical–cubic in shape and had an average particle size of less than 100 nm. In addition, the chemical bond structures of the nanoparticles were confirmed in detail by XPS elemental analysis. The highest saturation magnetization was recorded as 33.50 emu/g for the as-produced nanoparticles. The saturation magnetization of the nanoparticles decreased with increasing annealing temperature, while coercivity increased.     

MPI8 is Potent against SARS-CoV-2 by Inhibiting Dually and Selectively the SARS-CoV-2 Main Protease and the Host Cathepsin L**

A number of inhibitors have been developed for the SARS-CoV-2 main protease (M^Pro) as potential COVID-19 medications but little is known about their selectivity. Using enzymatic assays, we characterized inhibition of TMPRSS2, furin, and cathepsins B/K/L by more than a dozen of previously developed M^Pro inhibitors including MPI1-9, GC376, 11a, 10–1, 10–2, and 10–3. MPI1-9, GC376 and 11a all contain an aldehyde for the formation of a reversible covalent hemiacetal adduct with the M^Pro active site cysteine and 10–1, 10–2 and 10–3 contain a labile ester to exchange with the M^Pro active site cysteine for the formation of a thioester. Our data revealed that all these inhibitors are inert toward TMPRSS2 and furin. Diaryl esters also showed low inhibition of cathepsins. However, all aldehyde inhibitors displayed high potency in inhibiting three cathepsins. Their determined IC₅₀ values vary from 4.1 to 380 nM for cathepsin B, 0.079 to 2.3 nM for cathepsin L, and 0.35 to 180 nM for cathepsin K. All aldehyde inhibitors showed similar inhibition levels toward cathepsin L. A cellular analysis indicated high potency of MPI5 and MPI8 in inhibiting lysosomal activity, which is probably attributed to their inhibition of cathepsins. Among all aldehyde inhibitors, MPI8 shows the best selectivity toward cathepsin L. With respect to cathepsins B and K, the selective indices are 192 and 150, respectively. MPI8 is the most potent compound among all aldehyde inhibitors in cellular M^Pro inhibition potency and anti-SARS-CoV-2 activity in Vero E6 cells. Cathepsin L has been demonstrated to play a critical role in the SARS-CoV-2 cell entry. By selectively inhibiting both SARS-CoV-2 M^Pro and the host cathepsin L, MPI8 potentiates dual inhibition effects to synergize its overall antiviral potency and efficacy. Due to its high selectivity toward cathepsin L that reduces potential toxicity toward host cells and high cellular and antiviral potency, we urge serious consideration of MPI8 for preclinical and clinical investigations for treating COVID-19.