There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

News and social media platforms have implicated dietary supplements in the treatment and prevention of coronavirus disease 2019 (COVID-19). During this pandemic when information quickly evolves in the presence of contradicting messages and misinformation, the role of the pharmacist is essential. Here, we review theoretical mechanisms and evidence related to efficacy and safety of select supplements in the setting of COVID-19, including vitamin C, vitamin D, zinc, elderberry, and silver. Evidence evaluating these supplements in COVID-19 patients is lacking, and providers and patients should not rely on dietary supplements to prevent or treat COVID-19. Rather, reference to evidence-based guidelines should guide treatment decisions.

https://journals.sagepub.com/doi/pdf/10.1177/1060028020928052

Myth Busters: Dietary Supplements and COVID-19.

A current transformer (CT) is accurately modeled for representation of the CT saturation effects on digital protective relays. Simulation studies performed in the PSCAD/EMTDC platform are used to investigate the impacts of CT saturation on the current phasor estimation. A new algorithm is also proposed for detection and compensation of CT saturation effects, based on: a least error squares (LES) filter which estimates the phasor parameters of the CT secondary current; a novel saturation detection method which uses the output of the LES filter for saturation detection; and a new minimum estimation error tracking approach which enhances the precision of the phasor estimation. The proposed saturation detection/compensation algorithm is independent of the parameters of the CT, the burden, and the power system. The study results show that the proposed algorithm: 1) reconstructs the distorted current waveform, under dc and ac saturation conditions, with the required precision and speed and 2) performs satisfactorily under inductive burden and under deep and slight saturation conditions.

/pdf/compensation-of-the-current-transformer-saturation-effects-aokm4uygzk.pdf

Compensation of the Current-Transformer Saturation Effects for Digital Relays

In this paper, we present the first automated system-level analysis of multicore CPUs based on ARMv8 64-bit architecture (8-core, 28nm X-Gene 2 micro-server by AppliedMicro) when pushed to operate in scaled voltage conditions. We report detailed system-level effects including SDCs, corrected/uncorrected errors and application/system crashes. Our study reveals large voltage margins (that can be harnessed for energy savings) and also large $V_{min}$ variation among the 8 cores of the CPU chip, among 3 different chips (a nominal rated and two sigma chips), and among different benchmarks.Apart from the $V_{min}$ analysis we propose a new composite metric (severity) that aggregates the behavior of cores when undervolted and can support system operation and design protection decisions. Our undervolting characterization findings are the first reported analysis for an enterprise class 64-bit ARMv8 platform and we highlight key differences with previous studies on x86 platforms. We utilize the results of the system characterization along with performance counters information to measure the accuracy of prediction models for the behavior of benchmarks running in particular cores. Finally, we discuss how the detailed characterization and the prediction results can be effectively used to support design and system software decisions to harness voltage margins for energy efficiency while preserving operation correctness. Our findings show that, on average, 19.4% energy saving can be achieved without compromising the performance, while with 25% performance reduction, the energy saving raises to 38.8%.CCS CONCEPTS• Hardware → Power and energy → Power estimation and optimization; • Hardware → Robustness → Hardware reliability → Process, voltage and temperature variations

Harnessing voltage margins for energy efficiency in multicore CPUs

Residues from the processing of cassava roots (Manihot esculenta Crantz), or cassava peels, are evaluated as chemically modified adsorbents with H2O2, H2SO4, and NaOH, in the removal of metal ions Cd(II), Pb(II), and Cr(III) from contaminated water. Modified adsorbents were chemically characterized for their chemical composition and (point of zero charge), while adsorption tests determined the best conditions of pH, adsorbent mass, and contact time between adsorbent and adsorbate in the process of removal of the metal ions. Isotherms obtained from the preliminary results were linearized by Langmuir’s and Freudlich’s models. The thermodynamic parameters, such as , , and , were also evaluated. The modifying solutions proposed were effective in the modification of adsorbents and resulted in high capacity sorption materials. Equilibrium time between adsorbent and adsorbate for the solutions contaminated with metals is about 40 minutes. The Langmuir model adjusted to most results, indicating monolayers adsorption of Cd(II), Pb(II), and Cr(III). The values obtained for Langmuir show a higher adsorption capacity caused by chemical modifications, with values such as 19.54 mg Cd(II) per g of M. NaOH, 42.46 mg of Pb(II) per g of M. NaOH, and 43.97 mg of Cr(III) per g of M H2O2. Results showed that modified cassava peels are excellent adsorbent, renewable, high availability, and low-cost materials and a feasible alternative in the removal of metals in industries.

/pdf/chemical-modifications-of-cassava-peel-as-adsorbent-material-1oyvtwe2n9.pdf

Chemical Modifications of Cassava Peel as Adsorbent Material for Metals Ions from Wastewater

This chapter is an overview of the applications of particle swarm optimization for circuits and systems. The chapter is targeted for the Analog/RF circuits and systems designers. Design automation, modeling, optimization and testing of analog/RF circuits using particle swarm optimization is presented. Various applications of particle swarm optimization for circuits and systems are explained by examples.

Design Automation, Modeling, Optimization, and Testing of Analog/RF Circuits and Systems by Particle Swarm Optimization

Ex situ spectroscopic ellipsometry (SE) measurements have been employed to investigate the effect of liquid-phase hydrofluoric acid (HF) cleaning on Si surfaces for microelectromechanical systems application. The hydrogen terminated (H-terminated) Si surface was realized as an equivalent dielectric layer, and SE measurements are performed. The SE analyses indicate that after a 20-s 100:5 HF dip with rinse, the Si (100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si (100) surface was observed and analyzed by the ex-situ SE. Evidence for desorption of the H-terminated Si surface layer is studied using Fourier transform infrared spectroscopy and ellipsometry, and discussed. This piece of work explains the usage of an ex situ, non-destructive technique capable of showing state of passivation, the H-termination of Si surfaces.

/pdf/spectroscopic-ellipsometric-study-of-native-oxide-removal-by-4po7ccq8wr.pdf

Spectroscopic-ellipsometric study of native oxide removal by liquid phase HF process

SU-8 is being increasingly used as a compliant structural material for MEMS applications due to its interesting properties such as lower Young’s modulus and higher mechanical and thermal stability. One of the popular classes of MEMS devices is a piezoresitive microcantilever. Ultra-sensitive polymer composite cantilevers made up of SU-8 as a structural layer and 10% carbon Black in SU8 as a piezoresistive layer with lower Young’s modulus and higher gauge factor have been reported recently by our group. Higher electrical conductivity at lower concentration of conductive filler is of increased interest. Here we report a novel composite with purified multiwall carbon nanotubes (MWNT) in SU8 as a piezoresistor. MWNT were modified with octadecyl triphenyl phosphonium bromide (OTPB) in order to achieve debundled MWNT. A microcantilever device with integrated MWNT/SU-8 composite has been fabricated and characterized.

SU8 / modified MWNT composite for piezoresistive sensor application

Designing of an Asymmetric RF Oscillator for improved Signal Integrity, using Design of Experiments is presented and Taguchi Orthogonal Array is used for the same. Dependence of various physical parameters on output quality parameters that are Eye Height and Jitter, are shown by curves. Jitter is reduced and Eye Height is increased and as outcome of both, Eye SNR is increased. All in all, Designing of an Asymmetric Oscillator for better Signal Integrity is shown using Design of Experiments.

Designing Asymmetric 2.4 GHz RF Oscillator for improving Signal Integrity by Design of Experiments

Micro-cantilever arrays with different dimensions are fabricated by micromachining technique onto silicon substrate. These sputtered Gold-Coated micro-cantilevers were later surface functionalized. Scanning Electron Microscopy, Atomic Force Microscopy and Optical SWLI using LASER probe are employed to characterize the morphology and image measurement of the micro-cantilever arrays, respectively. Compared with conventional AFM and SPM measurement technique, the proposed method has demonstrated sufficient flexibility and reliability. The experimental results have been analyzed and presented in this paper for MEMS Micro-cantilevers. The scanning White Light Interferometry based two point high resolution optical method is presented for characterizing Micro-cantilevers and other MEMS micro-structures. The repeatable error and the repeatable precision produced in the proposed image measurement method is nanometre confirmable. In this piece of work, we investigate the micro-structure fabrication and image measurement of Length, Width and Step-Height of micro-cantilever arrays fabricated using bulk micromachining technique onto Silicon substrate.

Prakash R. Apte

Papers

Design Automation, Modeling, Optimization, and Testing of Analog/RF Circuits and Systems by Particle Swarm Optimization

Spectroscopic-ellipsometric study of native oxide removal by liquid phase HF process

SU8 / modified MWNT composite for piezoresistive sensor application

Designing Asymmetric 2.4 GHz RF Oscillator for improving Signal Integrity by Design of Experiments

Step-Height Measurement of Surface Functionalized Micromachined Microcantilever Using Scanning White Light Interferometry.