Determination of the Geometric Parameters of Electrode Systems for Electrical Impedance Myography: A Preliminary Study

The electrical impedance myography method is widely used in solving bionic control problems and consists of assessing the change in the electrical impedance magnitude during muscle contraction in real time. However, the choice of electrode systems sizes is not always properly considered when using the electrical impedance myography method in the existing approaches, which is important in terms of electrical impedance signal expressiveness and reproducibility. The article is devoted to the determination of acceptable sizes for the electrode systems for electrical impedance myography using the Pareto optimality assessment method and the electrical impedance signals formation model of the forearm area, taking into account the change in the electrophysical and geometric parameters of the skin and fat layer and muscle groups when performing actions with a hand. Numerical finite element simulation using anthropometric models of the forearm obtained by volunteers’ MRI 3D reconstructions was performed to determine a sufficient degree of the forearm anatomical features detailing in terms of the measured electrical impedance. For the mathematical description of electrical impedance relationships, a forearm two-layer model, represented by the skin-fat layer and muscles, was reasonably chosen, which adequately describes the change in electrical impedance when performing hand actions. Using this model, for the first time, an approach that can be used to determine the acceptable sizes of electrode systems for different parts of the body individually was proposed.

New Developments in Anterior Laryngeal Recording Technique During Neuromonitored Thyroid and Parathyroid Surgery

A recurrent laryngeal nerve (RLN) injury resulting in vocal fold paralysis and dysphonia remains a major source of morbidity after thyroid and parathyroid surgeries. Intraoperative neural monitoring (IONM) is increasingly accepted as an adjunct to the standard practice of visual RLN identification. Endotracheal tube (ET) surface recording electrode systems are now widely used for IONM; however, the major limitation of the clinical use of ET-based surface electrodes is the need to maintain constant contact between the electrodes and vocal folds during surgery to obtain a high-quality recording. An ET that is malpositioned during intubation or displaced during surgical manipulation can cause a false decrease or loss of electromyography (EMG) signal. Since it may be difficult to distinguish from an EMG change caused by a true RLN injury, a false loss or decrease in EMG signal may contribute to inappropriate surgical decision making. Therefore, researchers have investigated alternative electrode systems that circumvent common causes of poor accuracy in ET-based neuromonitoring. Recent experimental and clinical studies have confirmed the hypothesis that needle or adhesive surface recording electrodes attached to the thyroid cartilage (transcartilage and percutaneous recording) or attached to the overlying neck skin (transcutaneous recording) can provide functionality similar to that of ET-based electrodes, and these recording methods enable access to the EMG response of the vocalis muscle that originates from the inner surface of the thyroid cartilage. Studies also indicate that, during surgical manipulation of the trachea, transcartilage, percutaneous, and transcutaneous anterior laryngeal (AL) recording electrodes could be more stable than ET-based surface electrodes and could be equally accurate in depicting RLN stress during IONM. These findings show that these AL electrodes have potential applications in future designs of recording electrodes and support the use of IONM as a high-quality quantitative tool in thyroid and parathyroid surgery. This article reviews the major recent developments of newly emerging transcartilage, percutaneous, and transcutaneous AL recording techniques used in IONM and evaluates their contribution to improved voice outcomes in modern thyroid surgery.

Optical diagnostics of a dielectric surface discharge in the triggered vacuum gap using various dielectric materials

High-speed imaging and visible light stereomicroscopy were applied to do researches, which allowed us to find out differences in a dielectric surface discharge behavior in the triggered vacuum gap, when various dielectric materials (mica, muscovite and corundum-type ceramics) were used. Images of the discharge and the erosion in the electrode systems were analized to reveal that at the discharge on the ceramics surface a material of electrodes was mostly involved as a plasma-forming matter and on the mica it is the dielectric material.

Assessment of Partial Discharges in the Air by Application of Corona Camera

This paper reports the results of the analysis of measurements involving partial discharges (PD) occurring in the air using a corona camera (UV camera). The measurements were carried out in laboratory conditions and applied two electrode systems: needle–needle and needle–plate, in order to obtain various electric field distributions. The measurements of PDs, including a variety of alternatives, were carried out using a portable UV camera, taking into account the impact of the camera gain parameter and its distance from the PD sources. As a result, some important regularities and characteristics were identified that could significantly affect the ability to assess PDs by application of UV camera measurements. In addition, the results obtained can be employed for non-invasive diagnostic measurements performed on working power equipment and may be useful in further work on standardizing the result interpretation method obtained from measurements using a UV camera.

The Iron-Age of Storage Batteries: Techno-Economic Promises and Challenges

In this article, we explore the techno-economic promises and challenges related to iron electrode systems, specifically in the iron-air system. We study the discharge-charge products of an iron-air system in an aqueous electrolyte using an iron-water Pourbaix diagram. Using the discharge-charge products from the Pourbaix analysis, we construct a proposed baseline iron-air cell to estimate the basic voltage and capacity of the cell. This cell is then assembled into a battery pack to analyze the unit cost of a 150-hour iron-air system using a process-based cost model developed from the BatPaC model. With the appropriate choice of materials for an iron-air system, we estimate the total battery pack system cost for iron-air to be about US$25/kWh where the cell material costs are around US$5/kWh. The pack hardware costs, air delivery system, and manufacturing costs together account for over US$20/kWh. Through further engineering improvements, better catalysts, and cell chemistry improvements, the battery pack costs may be reduced further, which is promising for long-duration storage applications.

Simulation of acousto-optical deflectors for scanning receiving tracks of radar systems.

A technique is proposed for electrodynamic modeling of electrode systems of deflectors of optoelectronic spectrum analyzers of receiving paths of radar systems, which makes it possible to analyze the matching characteristics and adjust at the level of the electrode structure model, which helps to reduce the labor intensity of their manufacture and adjustment.

Metal Nanoparticles as Free-Floating Electrodes

Colloidal metal nanoparticles in an electrolyte environment are not only electrically charged but also electrochemically active objects. They have the typical character of metal electrodes with ongoing charge transfer processes on the metal/liquid interface. This picture is valid for the equilibrium state and also during the formation, growth, aggregation or dissolution of nanoparticles. This behavior can be understood in analogy to macroscopic mixed-electrode systems with a free-floating potential, which is determined by the competition between anodic and cathodic partial processes. In contrast to macroscopic electrodes, the small size of nanoparticles is responsible for significant effects of low numbers of elementary charges and for self-polarization effects as they are known from molecular systems, for example. The electrical properties of nanoparticles can be estimated by basic electrochemical equations. Reconsidering these fundamentals, the assembly behavior, the formation of nonspherical assemblies of nanoparticles and the growth and the corrosion behavior of metal nanoparticles, as well as the formation of core/shell particles, branched structures and particle networks, can be understood. The consequences of electrochemical behavior, charging and self-polarization for particle growth, shape formation and particle/particle interaction are discussed.

ABOUT THE POSSIBILITY OF CREATING AN EFFICIENT ENERGY ANALYZER OF CHARGED PARTICLE BEAMS BASED ON AXIALLYSYMMETRIC OCTUPOLE-CYLINDRICAL FIELD

One of the problems in creating systems for energy analysis of charged particles beams is to determine the deflecting field and calculation the shape of the deflecting electrodes. This article is devoted to the study of the possibility of creating an effective energy analyzer of charged particle beams based on multipole electrode systems. A previously unstudied type of a multipole-cylindrical field - an electrostatic axially-symmetrical octupole-cylindrical field was chosen as the deflecting field. The field is formed by using the superposition of an electrostatic cylindrical field and a circular octupole of various contributions. The family of the equipotentials of cylindrical octupoles with planes of symmetry and antisymmetry is calculated. The calculation and analysis of equipotential portraits of the electrostatic axially-symmetric octupole-cylindrical fields with different weight contributions of the cylindrical field and circular octupole are carried out.