Study on electric pulse destruction of diseased nematodes

The article presents the results of research on the use of electric discharges of current for the destruction of worms, larvae and galls of pathogenic nematodes. Nematodes consisting of round worms in the process of their vital activity penetrates the roots, stems and leaves of the plant, disrupting the integrity of tissues, cells and cellular structures, feeding on plant sap leads to lagging behind growth and development, contributes to the spread of various diseases, causes rot and infection. They can be found even in fruits and seeds of plants. Most often, worms form a kind of swelling growth in the roots, in the stems in the leaves and in the fruits, the growths of which are called galls. When unfavorable conditions arise, they move at an accelerated rate in the soil, maintaining their vitality. Therefore, their destruction using well-known methods such as agro technical, thermal biological, chemical, etc. is laborious and ineffective. The article describes an alternative electro technological method for the destruction of nematodes using electric current discharges, which provides the required destruction effect at the lowest cost.

A Review of Microbial Decontamination of Cereals by Non-Thermal Plasma

Cereals, an important food for humans and animals, may carry microbial contamination undesirable to the consumer or to the next generation of plants. Currently, non-thermal plasma (NTP) is often considered a new and safe microbicidal agent without or with very low adverse side effects. NTP is a partially or fully ionized gas at room temperature, typically generated by various electric discharges and rich in reactive particles. This review summarizes the effects of NTP on various types of cereals and products. NTP has undisputed beneficial effects with high potential for future practical use in decontamination and disinfection.

Anomalous transport of electrons in an electric discharge with transverse magnetic field

The experimental data showing the relationship of excitation of microwave oscillations with abnormally transport of electrons across the magnetic field in turbulent plasma are presented. The mechanism of the formation of the discharge current due to scattering of drift electrons in the near-electrode layers of the electric discharges on microwave oscillations has been substantiated. The conditions for the manifestation of the turbulent mechanism of anomalous electron transport through the magnetic barrier at the boundary of the toroidal electric discharge have been studied most fully. The mobility of electrons across a magnetic field is one of the main parameters of electric discharges that use crossed electric and magnetic fields for technological purposes.

Studies on Underwater Electric Discharge and Associated Pressure Waves

<p>Pulsed electric discharges in a liquid with the sufficiently wide range of energy contributions to them can generate diverging shock waves. А significant part of this energy is carried away by these waves from the center of the system to its periphery. At the same time, pulsed plasma-liquid systems limited by reflecting walls of both cylindrical and spherical geometry are insufficiently studied. A fundamental feature of such systems is the generation of a sequence of both diverging and converging (reflected) shock waves by a single pulse discharge. It was shown earlier that in a cylindrical plasma-liquid system with a height of the cylinder (h) comparable with the interelectrode distance (d), radius of the cylinder base R (at R >> h), when discharge current is increased, the ratio of the second diverging shock wave amplitude to the amplitude of the first diverging shock wave can be → 1. This leads to effective return of the energy carried away to the periphery back to the center of the system by converging shock waves. The collapse of the converging shock waves and initiated processes in the center of such plasma-fluid systems can be very interesting. The paper presents the results of experimental studies of pulsed cylindrical plasma-liquid system using both H₂O and a mixture of H₂O / D₂O and pure D₂O as a liquid. The energy-storage capacitor is charged by using a high voltage DC power supply (up to 70 kV).</p>

Studies on Underwater Electric Discharge and Associated Pressure Waves

<p>Pulsed electric discharges in a liquid with the sufficiently wide range of energy contributions to them can generate diverging shock waves. А significant part of this energy is carried away by these waves from the center of the system to its periphery. At the same time, pulsed plasma-liquid systems limited by reflecting walls of both cylindrical and spherical geometry are insufficiently studied. A fundamental feature of such systems is the generation of a sequence of both diverging and converging (reflected) shock waves by a single pulse discharge. It was shown earlier that in a cylindrical plasma-liquid system with a height of the cylinder (h) comparable with the interelectrode distance (d), radius of the cylinder base R (at R >> h), when discharge current is increased, the ratio of the second diverging shock wave amplitude to the amplitude of the first diverging shock wave can be → 1. This leads to effective return of the energy carried away to the periphery back to the center of the system by converging shock waves. The collapse of the converging shock waves and initiated processes in the center of such plasma-fluid systems can be very interesting. The paper presents the results of experimental studies of pulsed cylindrical plasma-liquid system using both H₂O and a mixture of H₂O / D₂O and pure D₂O as a liquid. The energy-storage capacitor is charged by using a high voltage DC power supply (up to 70 kV).</p>

Experimental and Thermal Investigation on Powder Mixed EDM Using FEM and Artificial Neural Networks

Electric discharge machining (EDM) process is one of the earliest and most extensively used unconventional machining processes. It is a noncontact machining process that uses a series of electric discharges to remove material from an electrically conductive workpiece. This article is aimed to do a comprehensive experimental and thermal investigation of the EDM, which can predict the machining characteristic and then optimize the output parameters with a newly integrated neural network-based methodology for modelling and optimal selection of process variables involved in powder mixed EDM (PMEDM) process. To compare and investigate the effects caused by powder of differently thermo physical properties on the EDM process performance with each other as well as the pure case, a series of experiments were conducted on a specially designed experimental setup developed in the laboratory. Peak current, pulse period, and source voltage are selected as the independent input parameters to evaluate the process performance in terms of material removal rate (MRR) and surface roughness (Ra). In addition, finite element method (FEM) is utilized for thermal analysis on EDM of stainless-steel 630 (SS630) grade. Further, back propagated neural network (BPNN) with feed forward architecture with analysis of variance (ANOVA) is used to find the best fit and approximate solutions to optimization and search problems. Finally, confirmation test results of experimental MRR are compared using the values of MRR obtained using FEM and ANN. Similarly, the test results of experimental Ra also compared with obtained Ra using ANN.

Study Regarding Process of the Electrical Discharge Machining with Magnetic Activation of the Welded Joints of some Materials High Alloy Steel

The scientific paper presents an extensive research on modeling and optimizing the technological parameters of the process for processing by processing electric discharges with massive electrode with and without magnetic activation. Scientific research is based on real data collected from the process of electrical discharges performed on various samples extracted from areas of welded joints of metal components made of high alloy steel. The processing of experimental data was performed both classically and actively, especially the method of the central factorial experiment composed of orthogonal and rotary. The process parameters that were initially modeled and subsequently optimized were based on a series of independent variables characteristic of dimensional processing by copying the shape of the electrical discharge processing. Subsequent research conclusions and directions, as well as original contributions, are an experimentally validated point of view and worthy of consideration. All these fundamental ideas highlighted above find their explanations and the corresponding explicit treatment in the content of this scientific paper that addresses both managers at all levels and researchers.

EXPERIMENTAL INVESTIGATION OF SURFACE TOPOGRAPHY OF AL7075-T6 ALLOY MACHINED BY EDM

Electrical discharge machining is one of the most important non-conventional machining processes for removing material from electrically conductive materials by the use of controlled electric discharges. EDM is a non-contact machining process, therefore, is free from mechanical stresses. This paper investigates the machining Al7075-T6 alloy by EDM using a copper electrode. Al7075-T6 alloy was selected, because of its growing use in a lot of engineering applications. The effect of electrical parameters, peak current and pulse-on time, on the surface integrity, was studied. Area surface roughness parameters (arithmetical mean height, Sa, and maximum height, Sz) were measured on all samples and 3D surface characterization has been carried out with confocal laser scanning microscopy. The experimental results showed that the surface roughness is mainly affected by the pulse-on time.

Analysis of the Campinas tornado (Brazil) in June 2016: damage track, radar characteristics and lightning observations of the supercell

Shortly after midnight on 05 June 2016, in the city of Campinas with > 1.2 million inhabitants, located in the State of São Paulo, intense precipitation, including hail, a large number of electric discharges and very strong wind gusts, causing significant damage, were recorded. No fatalities were documented, probably due to the day and time (Sunday around 00:20 Local Time). The affected areas are middle and even upper-middle class neighborhoods, with solid buildings, confirming the potency of the phenomenon. The destruction pattern indicates an intense perturbation resulting in the twisting of structures and tree branches, as well as large objects having been airborne over a distance of about 50 m, and large trees ripped from the ground, all suggesting that it was a tornado of category EF2-3. Severe damage was also reported from other towns in the region. About three hours before the tornado occurred in Campinas, an even stronger event devastated part of the small town of Jarinu, 40 km southeast of Campinas, possibly an EF3 tornado, which caused one fatality and overturned two semi-trailer trucks. No alerts that a disturbance of this magnitude would impact the region were raised, demonstrating that Campinas, and probably most other Brazilian cities and towns, are not prepared for such an event. During the beginning of June 2016, the synoptic situation over Brazil was characterized by a strong anticyclone centered over the northern half of South America at the 250 hPa level and bounded by a strong zonal Subtropical Jet (STJ) in the south, resulting in moist air being advected from the Amazon and Pacific region, creating favorable conditions for strong convection in the State of São Paulo, even during the night. Images from a Doppler S-band radar, located in Bauru, recorded a supercell storm lasting 8.5 hours, which traversed the eastern half of the State of São Paulo during the night of 04/05 June 2016 and spawned a tornado in the city of Campinas during the early hours of the morning (Local Time). Despite the distance of > 200 km, these radar observations confirmed typical tornado signatures, such as a rotational damage pattern, a hook echo and a mesocyclone with a rotational velocity of 12.5 m s−1. The supercell was accompanied by intense lightning activity throughout its life cycle with a “lightning jump” from 0 to 55 ground strokes per minute within 12 min just prior to the tornado touch-down, culminating in a frequency of 238 strokes per minute of Total Lightning. Although some of the Severe Storm Parameters calculated by the TITAN (Thunderstorm Identification, Tracking, Analysis and Nowcasting) Software were slightly lower than found in previous tornado cases in the State of São Paulo, this is most likely due to the fact that this was the first occurrence of a tornado observed by radar during the dry austral winter season in this region of Brazil, as well as a nocturnal event.