GNSS-Based Narrow-Angle UV Camera Targeting: Case Study of a Low-Cost MAD Robot.

One of the key challenges in Multi-Spectral Automatic Diagnostic (MAD) robot design is the precise targeting of narrow-angle cameras on a specific part of the equipment. The paper shows that a low-cost MAD robot, whose navigation system is based on open-source ArduRover firmware and a pair of low-cost Ublox F9P GNSS receivers, can inspect the 8 × 4 degree ultraviolet camera bounding the targeting error within 0.5 degrees. To achieve this result, we propose a new targeting procedure that can be implemented without any modifications in ArduRover firmware and outperforms more expensive solutions based on LiDAR SLAM and UWB. This paper will be interesting to the developers of robotic systems for power equipment inspection because it proposes a simple and effective solution for MAD robots' camera targeting and provides the first quantitative analysis of the GNSS reception conditions during power equipment inspection. This analysis is based on the experimental results collected during the inspection of the overhead power transmission lines and equipment inspections on the open switchgear of different power plants. Moreover, it includes not only satellite, dilution of precision, and positioning/heading estimation accuracy but also the direct measurements of angular errors that could be achieved on operating power plants using GNSS-only camera targeting.

Analysis of human skin sebum and animal meats by heat pulse desorption/mass spectrometry using proximity corona discharge ionization.

Recently, we have developed heat pulse desorption/mass spectrometry (HPD/MS). In HPD/MS, a heated N2 gas pulse was directed to the sample surface and desorbed analytes were mass analyzed by corona discharge ionization/mass spectrometry using an Orbitrap mass spectrometer. In this work, HPD/MS was applied to the analysis of skin surface components sampled from the forehead, nose, and jaw of three volunteers. It was found that various kinds of biological compounds such as squalene, free fatty acids, wax esters, triacylglycerols, and amino acids were detected. The simultaneous detection of compounds with a wide range of proton affinities suggests that the occurrence of consecutive proton transfer reactions is less likely to occur in the present experimental system. This is mainly due to the short distance of 1.5 mm between the tip of the corona needle and the inlet of the mass spectrometer (i.e., proximity corona discharge ion source). Under this condition, the transition time of the primary reactant ions (e.g., H3O+) from the tip of the corona discharge needle to the ion sampling orifice is roughly estimated to be ∼20 µs. This value nearly corresponds to the reaction lifetime of exoergic proton transfer reactions with a rate constant: ∼10-9 cm3 s-1 for the analytes of 1 ppm. Accordingly, analytes with concentrations less than 1 ppm would be ionized semi-quantitatively by the present method, making this method highly suitable for the rapid analysis of samples composed of complex mixture of compounds, e.g., non-target lipidomics.

Design, optimization, and evaluation of a wet electrostatic precipitator (ESP) for aerosol collection.

In this study, we developed, optimized, and evaluated in lab and field experiments a wet electrostatic precipitator (ESP) for the collection of ambient PM2.5 (particulate matter with aerodynamic diameter < 2.5 µm) into ultrapure water by applying an electrostatic charge to the particles. We operated the wet ESP at different flow rates and voltages to identify the optimal operating conditions. According to our experimental measurements, a flow rate of 125 lpm and an applied positive voltage of 11 kV resulted in a lower ozone generation of 133 ppb and a particle collection efficiency exceeding 80-90% in all size ranges. For the field tests, the wet ESP was compared with the versatile aerosol concentration enrichment system (VACES) connected to a BioSampler, a PTFE filter sampler, and an OC/EC analyzer (Sunset Laboratory Inc., USA) as a reference. The chemical analysis results indicated the wet ESP concentrations of metal and trace elements were in very good agreement with those measured by the VACES/BioSampler and PTFE filter sampler. Moreover, our results showed comparable total organic carbon (TOC) concentrations measured by the wet ESP, BioSampler, and OC/EC analyzer, while somewhat lower TOC concentrations were measured by the PTFE filter sampler, possibly due to the limitations of extracting water-insoluble organic carbon (WIOC) from a dry substrate in the latter sampler. The comparable TOC content in the wet ESP and BioSampler samples differs from previous findings that showed higher TOC content in BioSampler samples compared to those collected by dry ESP. The results of the Dithiothreitol (DTT) assay showed comparable DTT activity in the VACES/BioSampler and wet ESP PM samples while slightly lower in the PTFE filter samples. Overall, our results suggest that the wet ESP could be a promising alternative to other conventional sampling methods.

Detection of Corona Faults in Switchgear by Using 1D-CNN, LSTM, and 1D-CNN-LSTM Methods.

The damaging effects of corona faults have made them a major concern in metal-clad switchgear, requiring extreme caution during operation. Corona faults are also the primary cause of flashovers in medium-voltage metal-clad electrical equipment. The root cause of this issue is an electrical breakdown of the air due to electrical stress and poor air quality within the switchgear. Without proper preventative measures, a flashover can occur, resulting in serious harm to workers and equipment. As a result, detecting corona faults in switchgear and preventing electrical stress buildup in switches is critical. Recent years have seen the successful use of Deep Learning (DL) applications for corona and non-corona detection, owing to their autonomous feature learning capability. This paper systematically analyzes three deep learning techniques, namely 1D-CNN, LSTM, and 1D-CNN-LSTM hybrid models, to identify the most effective model for detecting corona faults. The hybrid 1D-CNN-LSTM model is deemed the best due to its high accuracy in both the time and frequency domains. This model analyzes the sound waves generated in switchgear to detect faults. The study examines model performance in both the time and frequency domains. In the time domain analysis (TDA), 1D-CNN achieved success rates of 98%, 98.4%, and 93.9%, while LSTM obtained success rates of 97.3%, 98.4%, and 92.4%. The most suitable model, the 1D-CNN-LSTM, achieved success rates of 99.3%, 98.4%, and 98.4% in differentiating corona and non-corona cases during training, validation, and testing. In the frequency domain analysis (FDA), 1D-CNN achieved success rates of 100%, 95.8%, and 95.8%, while LSTM obtained success rates of 100%, 100%, and 100%. The 1D-CNN-LSTM model achieved a 100%, 100%, and 100% success rate during training, validation, and testing. Hence, the developed algorithms achieved high performance in identifying corona faults in switchgear, particularly the 1D-CNN-LSTM model due to its accuracy in detecting corona faults in both the time and frequency domains.

Advancements in Plasma Agriculture: A Review of Recent Studies.

This review is devoted to a topic of high interest in recent times-the use of plasma technologies in agriculture. The increased attention to these studies is primarily due to the demand for the intensification of food production and, at the same time, the request to reduce the use of pesticides. We analyzed publications, focusing on research conducted in the last 3 years, to identify the main achievements of plasma agrotechnologies and key obstacles to their widespread implementation in practice. We considered the main types of plasma sources used in this area, their advantages and limitations, which determine the areas of application. We also considered the use of plasma-activated liquids and the efficiency of their production by various types of plasma sources.

Co-Benefits of Pollutant Removal, Water, and Heat Recovery from Flue Gas through Phase Transition Enhanced by Corona Discharge.

Pollutant removal and resource recovery from high-humidity flue gas after desulfurization in a thermal power plant are crucial for improving air quality and saving energy. This study developed a flue gas treatment method involving phase transition enhanced by corona discharge based on laboratory research and established a field-scale unit for demonstration. The results indicate that an adequate increase in size will improve the ease of particle capture. A wet electrostatic precipitator is applied before the condensing heat exchangers to enhance the particle growth and capture processes. This results in an increase of 58% in the particle median diameter in the heat exchanger and an emission concentration below 1 mg/m3. Other pollutants, such as SO3 and Hg, can also be removed with emission concentrations of 0.13 mg/m3 and 1.10 µg/m3, respectively. Under the condensation enhancement of the method, it is possible to recover up to 3.26 t/h of water from 200 000 m3/h saturated flue gas (323 K), and the quality of the recovered water meets the standards stipulated in China. Additionally, charge-induced condensation is shown to improve heat recovery, resulting in the recovery of more than 43.34 kJ/h·m3 of heat from the flue gas. This method is expected to save 2628 t of standard coal and reduce carbon dioxide emission by 2% annually, contributing to environmental protection and global-warming mitigation.

Atmospheric plasma-based approaches for the degradation of dimethyl phthalate (DMP) in water.

Cold plasma based treatment of contaminated water is becoming a promising novel green remediation option. This study assessed the performance of two different cold plasma reactors, using, respectively, a self-pulsing discharge (SPD) and a multipin corona discharge (MCD), in the degradation of dimethyl phthalate (DMP), a persistent and ubiquitous pollutant of the aquatic environment. The process kinetics and energy efficiency, as well as the main plasma generated reactive species were determined under various operating conditions concerning the plasma feed gas and flowrate, the voltage polarity, the input power, the DMP initial concentration, the liquid conductivity, and the aqueous matrix used to prepare DMP solutions for these experiments. The MCD reactor, operated with air as plasma feed gas and negative voltage polarity, gave the best results in terms of rate and energy efficiency. Moreover, variations in plasma input power and in the liquid conductivity have limited effect on DMP degradation rate, making this reactor suitable for treating liquids with a range of initial conductivities The effects of DMP initial concentration on its rate of degradation and on the process energy efficiency were also investigated. Differences in the efficiency of production and distribution of plasma generated reactive species, notably •OH and H2O2, observed for the two tested reactors are discussed in terms of different extension of the plasma/liquid interface and diffusion into the bulk solution. It is proposed that among the reactive species, •OH foremost, and O3 to a lesser extent, play a pivotal role in DMP degradation, while the contribution of H2O2 appears to be limited. The rate of DMP degradation was not drastically different in Milli-Q water and in tap water, a positive outcome in view of practical applications of the technology. The lower rate observed in tap than in Milli-Q water is attributed to the presence of bicarbonate and carbonate, which are known scavengers of hydroxyl radicals.

Portable Digital Linear Ion Trap Mass Spectrometer Based on Separate-Region Corona Discharge Ionization Source for On-Site Rapid Detection of Illegal Drugs.

As narcotic control has become worse in the past decade and the death toll of drug abuse hits a record high, there is an increasing demand for on-site rapid detection of illegal drugs. This work developed a portable digital linear ion trap mass spectrometer based on separate-region corona discharge ionization source to meet this need. A separate design of discharge and reaction regions was adopted with filter air as both carrier gas for the analyte and protection of the corona discharge needle. The linear ion trap was driven by a digital waveform with a low voltage (±100 V) to cover a mass range of 50-500 Da with a unit resolution at a scan rate of 10,000 Da/s. Eighteen representative drugs were analyzed, demonstrating excellent qualitative analysis capability. Tandem mass spectrometry (MS/MS) was also performed by ion isolation and collision-induced dissociation (CID) with air as a buffer gas. With cocaine as an example, over two orders of magnitude dynamic range and 10 pg of detection limit were achieved. A single analysis time of less than 10 s was obtained by comparing the information of characteristic ions and product ions with the built-in database. Analysis of a real-world sample further validated the feasibility of the instrument, with the results benchmarked by GC-MS. The developed system has powerful analytical capability without using consumables including solvent and inert gas, meeting the requirements of on-site rapid detection applications.

Disinfection and Electrostatic Recovery of N95 Respirators by Corona Discharge for Safe Reuse.

With the COVID-19 pandemic surging, the demand for masks is challenging, especially in less-developed areas across the world. Billions of used masks are threatening the environment as a new source of plastic pollution. In this paper, corona discharge (CD) was explored as a safe and reliable method for mask reuse to alleviate the situation. CD can disinfect masks and simultaneously restore electrostatic charges to prevent filtration efficiency deterioration. Electric field, ions, and reactive species generated by CD cause DNA damage and protein denaturation to effectively disinfect N95 respirators. Log reduction of 2-3 against Escherichia coli can be easily reached within 7.5 min. Log reduction of up to 6 can be reached after three cycles of treatment with optimized parameters. CD disinfection is a broad spectrum with log reduction >1 against yeast and >2.5 against spores. N95 respirators can be recharged within 30 s of treatment and the charges can be retained at a higher level than brand-new masks for at least 5 days. The filtration efficiency of masks was maintained at ∼95% after 15 cycles of treatment. CD can provide at least 10 cycles of safe reuse with benefits of high safety, affordability, accessibility, and device scalability/portability.

Indoor PM2.5 removal efficiency of two different non-thermal plasma systems.

The use of non-thermal plasma (NTP) generators in air processing systems and their duct networks to improve indoor air quality (IAQ) has grown considerably in recent years. This paper reviews the advantages and disadvantages of NTP generators for IAQ improvement in biological, chemical and particulate pollutant terms. Also, it assesses and compares the ability of a multipin corona discharge (MPCD) and a dielectric barrier discharge (DBD) generator to reduce the concentration of fine particulate matter (PM2.5) in recycled, unfiltered air in a refrigeration chamber. The MPCD generator was found to have a higher PM2.5 removal efficiency; also, it was faster in removing pollutants, used less energy, and produced much less ozone. The fact that the MPCD generator performed better was seemingly the result of its increased ion production mainly. NTP generators, however, cannot match air filtration media purifiers in this respect as the latter are much more effective in removing particles. Besides, NTP-based air purifying technology continues to be subject to a major drawback, namely: the formation of ozone as a by-product. In any case, the ozone generation was uncorrelated to ion emission when using different technologies.

Non-Thermal Plasma Sources Based on Cometary and Point-to-Ring Discharges.

A non-thermal plasma (NTP) is a promising tool against the development of bacterial, viral, and fungal diseases. The recently revealed development of microbial resistance to traditional drugs has increased interest in the use of NTPs. We have studied and compared the physical and microbicidal properties of two types of NTP sources based on a cometary discharge in the point-to-point electrode configuration and a corona discharge in the point-to-ring electrode configuration. The electrical and emission properties of both discharges are reported. The microbicidal effect of NTP sources was tested on three strains of the bacterium Staphylococcus aureus (including the methicillin-resistant strain), the bacterium Pseudomonas aeruginosa, the yeast Candida albicans, and the micromycete Trichophyton interdigitale. In general, the cometary discharge is a less stable source of NTP and mostly forms smaller but more rapidly emerging inhibition zones on agar plates. Due to the point-to-ring electrode configuration, the second type of discharge has higher stability and provides larger affected but often not completely inhibited zones. However, after 60 min of exposure, the NTP sources based on the cometary and point-to-ring discharges showed a similar microbicidal effect for bacteria and an individual effect for microscopic fungi.

Profiling nucleotides in low numbers of mammalian cells by sheathless CE-MS in positive ion mode: Circumventing corona discharge.

Negative ion mode nano-ESI-MS is often considered for the analysis of acidic compounds, including nucleotides. However, under high aqueous separation conditions, corona discharge is frequently observed at emitter tips, which may result in low ion abundances and reduced nano-ESI needle emitter lifetimes. In this work, we introduce a sheathless CE-MS method for the highly efficient and sensitive analysis of nucleotides employing ESI in positive ion mode, thereby fully circumventing corona discharge. By using a background electrolyte of 16 mM ammonium acetate (pH 9.7) a mixture of 12 nucleotides, composed of mono-, di-, and tri-phosphates, could be efficiently analyzed with plate numbers per meter above 220 000 and with LODs in the range from 0.06 to 1.3 nM, corresponding to 0.4 to 8.6 attomole, when using an injection volume of about 6.5 nL only. The utility of the method was demonstrated for the profiling of nucleotides in low numbers of mammalian cells using HepG2 cells as a model system. Endogenous nucleotides could be efficiently analyzed in extracts from 50 000 down to 500 HepG2 cells only. Moreover, apart from nucleotides, also some nicotinamide-adenine dinucleotides and amino acids could be analyzed under these conditions, thereby clearly illustrating the utility of this approach for metabolic profiling of low amounts of biological material.

Behavior of Ultrafine Particles in Electro-Hydrodynamic Flow Induced by Corona Discharge.

Ultrafine particle behavior in electro-hydrodynamic (EHD) flow induced by corona discharge is studied experimentally and numerically. The EHD flow serves as a primary particle aspiration/sampling mechanism, the collector does not require any additional flow generation. Multiphysics numerical model couples the ion transport equation and the Navier-Stokes equations (NSE) to solve for the spatiotemporal distribution of electric field, charge density, and flow field, the results are compared with experimental velocity profiles at the exit. The computed velocity and flow rate data are in good agreement with the experimental data; the maximum velocity is located at the axis and ranges from 1 m/s to 4 m/s as a function of corona voltage. Experimentally evaluated particle transmission trends for ambient and NaCl nanoparticles particles in the 20 nm - 150 nm range are in good agreement with the theoretical models. However, for particles in the 10 nm - 20 nm size range, the transmission is lower due to the increased particle charging resulted from their exposure to the high-intensity electric field and high charge density in the EHD driven flow. These conditions yield a high probability of particles below 20 nm to acquire and hold a unit charge. The transmission is lower for smaller particle (10 nm) due to their high charge to mass ratio, and it increases as the single-charged particles grow in mass up to 20 nm, resulting in their lower electrical mobility. For particles larger than 20 nm, the electrical mobility increases again as they can acquire multiple charges. The results shed insight into interaction of nanoparticle and ions in high electrical field environment, that occur in primary EHD driven flows and in the secondary flows generated by corona discharge.

Hypothesis: The electrical properties of coronavirus.

To help investigate the relationship between inflammatory and other symptoms of coronavirus and the protein-protein interactions (PPI) that occur between viral proteins and protein molecules of the host cell, I propose that the electrostatic discharge (ESD) exists including corona discharge to lead to ozone gas. I cite evidence in support of this hypothesis. I hope that the proposed will inspire new studies in finding effective treatments and vaccines for individuals with coronavirus disease in 2019. I suggest possible future studies that may lend more credibility to the proposed.

Corona discharge electrospray ionization of formate-containing solutions enables in-source reduction of disulfide bonds.

Disulfide bonds are critical linkages for maintaining protein structure and enzyme activity. These linkages, however, can limit peptide sequencing efforts by mass spectrometry (MS) and often require chemical reduction and alkylation. Under such conditions, information regarding cysteine connectivity is lost. Online partial disulfide reduction within the electrospray (ESI) source has recently been established as a means to identify complex cysteine linkage patterns in a liquid chromatography-MS experiment without the need for sample pre-treatment. Corona discharge (CD) is invoked as the causative factor of this in-source reduction (ISR); however, evidence remains largely circumstantial. In this study, we demonstrate that instrumental factors-nebulizing gas, ESI capillary material, organic solvent content, ESI spray needle-to-MS distance-all modulate the degree of reduction observed for the single disulfide in oxytocin, further implicating CD in ISR. Rigorous analysis of solution conditions, however, reveals that corona discharge alone can induce only minor disulfide reduction. We establish that CD-ESI of peptide solutions containing formic acid or its conjugate base results in a dramatic increase in disulfide reduction. It is also determined that ISR is exacerbated at low pH for complex peptides containing multiple disulfide bonds and possessing higher-order structure, as well as for a small protein. Overall, our results demonstrate that ESI of formate/formic acid-containing solutions under corona discharge conditions facilitates disulfide ISR, likely by a similar reduction pathway measured in γ-radiolysis studies nearly three decades ago.

Development and application of SBA-15 assisted electromembrane extraction followed by corona discharge ion mobility spectrometry for the determination of Thiabendazole in fruit juice samples.

A new sample preparation method based on SBA-15 assisted electromembrane extraction coupled with corona discharge ion mobility spectrometer was developed for the determination of Thiabendazole as a model basic pesticide in fruit juice samples. The addition of SBA-15 in the supported liquid membrane in electromembrane extraction system not only can lead to enhancement of the effective surface area, but also introducing the negatively charged silanol groups into supported liquid membrane might improve migration of positively charged analytes toward the supported liquid membrane and finally into the acceptor solution. To investigate the effect of the presence of SBA-15 in the supported liquid membrane on the extraction efficiency, a comparative study was carried out between the conventional electromembrane extraction and SBA-15/electromembrane extraction methods. Under the optimized conditions, SBA-15/electromembrane extraction method showed higher extraction efficiencies in comparison with conventional electromembrane extraction method. SBA-15/electromembrane extraction method exhibited a low limit of detection (0.9 ng/mL), high preconcentration factor (167) and high recovery (83%). Finally, the applicability of SBA-15/electromembrane extraction method was studied by the extraction and determination of Thiabendazole as a model basic pesticide in fruit juice samples.

A Real-Time Ultraviolet Radiation Imaging System Using an Organic Photoconductive Image Sensor.

We have developed a real time ultraviolet (UV) imaging system that can visualize both invisible UV light and a visible (VIS) background scene in an outdoor environment. As a UV/VIS image sensor, an organic photoconductive film (OPF) imager is employed. The OPF has an intrinsically higher sensitivity in the UV wavelength region than those of conventional consumer Complementary Metal Oxide Semiconductor (CMOS) image sensors (CIS) or Charge Coupled Devices (CCD). As particular examples, imaging of hydrogen flame and of corona discharge is demonstrated. UV images overlapped on background scenes are simply made by on-board background subtraction. The system is capable of imaging weaker UV signals by four orders of magnitude than that of VIS background. It is applicable not only to future hydrogen supply stations but also to other UV/VIS monitor systems requiring UV sensitivity under strong visible radiation environment such as power supply substations.

Cold Plasma as an Innovative Construction Method of Voltammetric Biosensor Based on Laccase.

Development of new, faster methods of biosensor construction is a huge challenge for current science and industry. In this work, biosensor construction was carried out using a new soft plasma polymerization (SPP) method in which a bio-recognition layer of laccase enzyme was polymerized and bonded to a glassy carbon electrode (GCE) substrate under atmospheric pressure with a corona discharge jet. Laccase belongs to the oxidoreductase enzyme group with four copper atoms in its active center. Application of the corona SPP plasma method allows reduction of the time needed for biosensor construction from several hours to minutes. The presented work includes optimization of the laccase bio-recognition layer deposition time, structural studies of the deposited laccase layer, as well as study of the fabricated biosensor applicability for the determination of Rutin in real pharmaceutical samples. This method produces a biosensor with two linear ranges from 0.3 µmol/dm³ to 0.5 µmol/dm³ and from 0.8 µmol/dm³ to 16 µmol/dm³ of Rutin concentration. Results shown in this work indicate that application of the one-step, corona SPP method enables biosensor construction with comparable analytical parameters to biosensors fabricated by conventional, multi-step, wet methods.

Parametric Study and Optimization of Flow Characteristics of Wire-Nonparallel Plate-Type Electrostatic Air Accelerators.

Wire and nonparallel plate electrode-type electrostatic air accelerators have attracted significant interest. The physical process involved in using accelerators is complicated. Moreover, mechanisms are unclear, especially for accelerators with double- and multiwire electrodes. In this study, the two-dimensional (2D) model of a wire-nonparallel plate-type accelerator validated by experiments is established with a finite element method. Onset voltage, average current, and outlet average velocity are analyzed with respect to different parameters. Onset voltage is derived by the proposed quadratic regression extrapolation method. Moreover, current is affected by interference and discharge effects, while velocity is also influenced by the suction effect. For the single-wire electrode, high wind speed can be obtained by either increasing channel slope or placing the wire near the entry section. For the double-wire electrode, velocity can be further increased when one of the wires is placed near the inlet and the distance between the two wires is widened. Comparatively, the velocity of the three-wire electrode is higher with larger gaps between wires and stronger discharge effect. The highest velocity is obtained by the four-wire electrode. Comparisons indicate that higher velocity can be obtained with weaker interference effect, stronger suction effect, and intensified discharge effect. Optimum parameter combinations are considered by the Taguchi method. Consequently, velocity can be enhanced by more than 39% after optimization compared with the reference design.

Plasma-based ambient mass spectrometry techniques: The current status and future prospective.

Plasma-based ambient mass spectrometry is emerging as a frontier technology for direct analysis of sample that employs low-energy plasma as the ionization reagent. The versatile sources of ambient mass spectrometry (MS) can be classified according to the plasma formation approaches; namely, corona discharge, glow discharge, dielectric barrier discharge, and microwave-induced discharge. These techniques allow pretreatment-free detection of samples, ranging from biological materials (e.g., flies, bacteria, plants, tissues, peptides, metabolites, and lipids) to pharmaceuticals, food-stuffs, polymers, chemical warfare reagents, and daily-use chemicals. In most cases, plasma-based ambient MS performs well as a qualitative tool and as an analyzer for semi-quantitation. Herein, we provide an overview of the key concepts, mechanisms, and applications of plasma-based ambient MS techniques, and discuss the challenges and outlook.