High Voltage Electrostatic Field Research Articles

A Review on Current Nanofiber Technologies: Electrospinning, Centrifugal Spinning, and Electro‐Centrifugal Spinning

AbstractNanofiber‐based products are widely used in the fields of public health, air/water filtration, energy storage, etc. The demand for nonwoven products is rapidly increasing especially after COVID‐19 pandemic. Electrospinning is the most popular technology to produce nanofiber‐based products from various kinds of materials in bench and commercial scales. While centrifugal spinning and electro‐centrifugal spinning are considered to be the other two well‐known technologies to fabricate nanofibers. However, their developments are restricted mainly due to the unnormalized spinning devices and spinning principles. High solution concentration and high production efficiency are the two main strengths of centrifugal spinning, but beaded fibers can be formed easily due to air perturbation or device vibration. Electro‐centrifugal spinning is formed by introducing a high voltage electrostatic field into the centrifugal spinning system, which suppresses the formation of beaded fibers and results in producing elegant nanofibers. It is believed that electrospinning can be replaced by electro‐centrifugal spinning in some specific application areas. This article gives an overview on the existing devices and the crucial processing parameters of these nanofiber technologies, also constructive suggestions are proposed to facilitate the development of centrifugal and electro‐centrifugal spinning.

Effects of HVEF treatment on the physicochemical properties and bacterial communities of Larimichthys crocea fillets during refrigerated storage

SummaryThis study investigated the effects of a high voltage electrostatic field (HVEF) on the physicochemical properties and bacterial communities of Larimichthys crocea (L. crocea) fillets. HVEF‐treated samples (5, 10 and 15 kV/m) and control samples (0 kV/m) were stored at −1 ± 0.5 °C for 0, 4, 8, 12, 16, 20 and 24 days. Compared with the control group, the HVEF‐treated groups (10 and 15 kV/m) had less muscle fibre damage and better tissue structures. In addition, HVEF treatment delayed the decrease in springiness and hardness, improved the quality of fish during refrigerated storage and effectively extended the shelf‐life of L. crocea fillets. The HVEF‐treated groups had a considerably lower total viable count (TVC) than the control group. Furthermore, high‐throughput sequencing revealed that HVEF treatment reduced the relative abundance of Shewanella by 21.48% at 8th day, implying that spoilage bacteria growth was inhibited. The results indicated that HVEF treatment could be used as a new technology in the fish processing industry to delay L. crocea fillet deterioration.

Deflection of particles of a laser erosion plume under the action of a high-voltage electrostatic field during ablation processing of titanium

The ablative particles of the laser erosion torch during the processing of titanium with subpicosecond pulses were analyzed for vertical deflection under the action of an electrostatic field. The installation of a solid-state ytterbium laser with a radiation wavelength of 1030 nm was used. The photographs of the registered deviations of ablation particles in the region of propagation of the electrostatic field were obtained. The dependence of the vertical deflections of ablated particles on the laser pulse energy and the distance from the electrodes to the target is calculated.

High-voltage direct current triboelectric nanogenerator based on charge pump and air ionization for electrospinning

Triboelectric nanogenerators (TENGs) have been widely studied as a new type of environmentally friendly green energy. But traditional TENGs mostly generate alternating current (AC) that changes periodically. Here, a novel rolling-mode direct-current triboelectric nanogenerator (DC-TENG) is designed. It consists of rollers of two different materials, a rubber belt and two metal electrodes. During the rotation, the rubber belt continuously transfers the charge from one roller to the other, so that the positive and negative charges accumulate on the two rollers respectively. The high-voltage electrostatic field generated between the roller and the electrode ionizes the air, so that the two electrodes are charged with different charges, so as to achieve DC output. The rolling-mode DC-TENG can generate a DC output of up to 16 kV and 5 μA. This device can act as a high-voltage power source for electrospinning to prepare different polymer nanofibers. DC-TENG can be directly used as a DC power supply, successfully lighting about 4000 LEDs. At the same time, it can charge the capacitor and store energy and light up the hygrometer. This work proposes a new model of DC-TENG that successfully realizes DC output, and demonstrates that this DC-TENG provides practical applications in the fields of high-voltage electrostatics and energy supply. In conclusion, this study provides a convenient and effective new strategy for DC TENG to minimize wear losses and maintain stable DC triboelectric output.

Effects of High Voltage Electrostatic Field and Gelatin-Gum Arabic Composite Film on Color Protection of Freeze-dried Grapefruit Slices

Effects of High Voltage Electrostatic Field and Gelatin-Gum Arabic Composite Film on Color Protection of Freeze-dried Grapefruit Slices

Modelling Particle Motion during High-Voltage Electrostatic Abrasive Implantation Based on Multi-Physics Field Coupling

Electrostatic abrasive implantation technology is a classical process based on electrostatic field to implant abrasive particles into base material. However, there is still not a quantitative model to ensure the implantation performance due to the fact that the electrostatic abrasive implantation is a complex multi-physics coupled process. To ensure the quality of sandpaper and elucidate the complex motion mechanism of Al2O3 based abrasive particles in a high voltage electrostatic field, a multi-physical field coupling simulation model is proposed. First, the mechanical model is constructed for the complex problem of the electrostatic abrasive implantation process. Then, the field model is established for the problem that the superposition of multi-physical fields leads to complicated environmental conditions. Finally, the evaluation model is established for the problems that the abrasive planting effect is difficult to evaluate and the planting parameters are difficult to adjust. Besides, a tailored electrostatic abrasive planting testing equipment is designed for the implantation performance analysis purpose. Single-parameter electrostatic abrasive planting experiments were conducted to analyze and verify the effect of different pole plate voltage and pole plate spacing on the abrasive implantation rate. To ensure the implantation performance, the applicable pole plate spacing ranges from 30 mm to 50 mm and the suitable voltage is 20–40 kV according to the simulation result in the proposed two models. Meanwhile, the implantation rate experimentation shows the coupling field model coincides with the experiments better. The key factors affecting the electrostatic abrasive planting process are identified, and a feasible multi-physical field coupled abrasive particle motion simulation model is proposed.

High-voltage electrostatic field-assisted modified atmosphere packaging for long-term storage of pakchoi and avoidance of off-flavors

Pakchoi is an important source of many essential nutrients for humans, but the leaves are prone to yellowing and rotting. This study aimed to maintain the quality of post-harvest pakchoi by using non-thermal high-voltage electrostatic field (HVEF) treatment in combination with modified atmosphere packaging (MAP) to compensate for each other's technical shortcomings and extend the shelf life of pakchoi. After 40 days of storage, HVEF at 4 kV/cm effectively degraded the volatile flavor components within the package, maintaining the chlorophyll and ascorbic acid content. It also reduced the microbial count by 1.82 ± log CFU g−1 (at 25 days) compared to the single MAP treatment (p < 0.05). The combined treatment of pakchoi has been verified by low-field nuclear magnetic resonance to have relatively low water mobility as well as lower electrolyte permeability and better texture than the single treatment. So, it has a higher sensory score. The HVEF assisted treatment resulted in lower respiration rates in the modified atmosphere packed pakchoi and changes in polyphenol oxidase (PPO) and superoxide dismutase (SOD) activities by affecting metal ion valence and enzyme conformation in favor of long-term storage. Principal component analysis (PCA) showed that the sensory and nutritional qualities of pakchoi treated with MAP and HVEF at 4 kV/cm in concert were closest to those of fresh samples. As a result, the shelf life of the pakchoi was successfully extended to 40 days while the pakchoi with a single MAP treatment lost its edible value at 25 days. HVEF assisted modified atmosphere packaging is expected to be an environmentally friendly, efficient and promising preservation technology. Industrial relevanceThis research provides new ideas for reducing the production of off-flavors vegetables in modified atmosphere packaging and extending the shelf life of vegetables. After modified atmosphere packaging the vegetables receive a high-voltage electrostatic field treatment at five-day intervals. This intermittent post-treatment is both low energy and efficient; and the antibiotic effect on microorganisms is unmatched by other integrated treatments. This opens up new possibilities for the transportation of fresh vegetables by fleets on long sea voyages and for the marketing of off seasonable fruit and vegetables in extreme weather.

Influence of electrochemically deposited TiO2 on the anti-weathering properties of heat-treated wood

ABSTRACT Ultraviolet light-induced discoloration is a noticeable issue when heat-treated wood is used outdoors. In this study, titanium dioxide (TiO2) particles were electrochemically deposited on the surface of heat-treated wood via a high-voltage electrostatic field (HVEF). Natural and artificial weathering tests were carried out to evaluate the anti-weathering properties after the electrochemical deposition. During HVEF treatment, Ti particles were triggered in the form of Ti4+. Ti4+ grafted with the hydroxyl groups of hemicellulose and lignin in the form of Ti–OH, and TiO2 was produced due to the oxidizing atmosphere generated by HVEF. TiO2 and Ti–OH played roles as UV absorbers, reducing degradation and discoloration of heat-treated wood. The photodegradation of lignin was alleviated effectively during both the artificial and natural weathering. The stability of wood color was remained. After the artificial weathering, the values of L*, a* and b* of the electrochemical depositied sample were 55, 10 and 25, respectively. The leaching amount of TiO2 after artificial or natural weathering was less than 6% or 40%, respectively determined by atomic absorption spectroscopy. The results suggest the feasibility of the electrochemical deposition of TiO2 for improving the anti-weathering properties of heat-treated wood and provide an effective strategy for industrial wood modification.

Effect of High-Voltage Electrostatic Field Heating on the Oxidative Stability of Duck Oils Containing Diacylglycerol.

High-voltage electrostatic field (HVEF) as an emerging green technology is just at the beginning of its use in meat products and by-products processing. In this study, we employed duck oil to produce duck-oil-based diacylglycerol (DAG), termed DDAG. Three different DDAG volume concentrations (0, 20%, and 100%) of hybrid duck oils, named 0%DDAG, 20%DDAG, and 100%DDAG, respectively, were used to investigate their thermal oxidation stability in high-voltage electrostatic field heating and ordinary heating at 180 ± 1 ℃. The results show that the content of saturated fatty acids and trans fatty acids of the three kinds of duck oils increased (p < 0.05), while that of polyunsaturated fatty acids decreased (p < 0.05) from 0 h to 8 h. After heating for 8 h, the low-field nuclear magnetic resonance showed that the transverse relaxation time (T21) of the three oils decreased (p < 0.05), while the peak area ratio (S21) was increased significantly (p < 0.05). The above results indicate that more oxidation products were generated with heating time. The peroxide value, the content of saturated fatty acids, and the S21 increased with more DAG in the duck oil, which suggested that the oxidation stability was likely negatively correlated with the DAG content. Moreover, the peroxide value, the content of saturated fatty acids and trans fatty acids, and the S21 of the three concentrations of duck oils were higher (p < 0.05) under ordinary heating than HVEF heating. It was concluded that HVEF could restrain the speed of the thermal oxidation reaction occurring in the duck oil heating and be applied in heating conditions.

In Vitro Antibacterial Mechanism of High-Voltage Electrostatic Field against Acinetobacter johnsonii.

This study aimed to investigate the antibacterial properties and mechanisms of a high-voltage static electric field (HVEF) in Acinetobacter johnsonii, which were assessed from the perspective of biochemical properties and stress-related genes. The time/voltage-kill assays and growth curves showed that an HVEF decreased the number of bacteria and OD600 values. In addition, HVEF treatment caused the leakage of cell contents (nucleic acids and proteins), increased the electrical conductivity and amounts of reactive oxygen substances (ROS) (16.88 fold), and decreased the activity of Na+ K+-ATPase in A. johnsonii. Moreover, the changes in the expression levels of genes involved in oxidative stress and DNA damage in the treated A. johnsonii cells suggested that HVEF treatment could induce oxidative stress and DNA sub-damage. This study will provide useful information for the development and application of an HVEF in food safety.

Interfacial properties of windmill palm (Trachycarpus fortunei) fiber reinforced laminated veneer lumber (LVL) composites under high voltage electrostatic field (HVEF)

The acid/alkali pretreatment of windmill palm fiber (WPF) and the application of high voltage electrostatic force (HVEF) technology were used to prepare WPF-reinforced laminated veneer lumber (LVL). The effects of acid/alkali pretreatment on the surface morphology, chemical composition, crystallinity and mechanical properties of WPF were investigated. Moreover, the effects of intensity of HVEF on chemical composition and wettability of WPF were analyzed. Based on the mechanical experiment of WPF reinforced LVL composites, the mechanism of acid/alkali pretreatment and HVEF for the reinforcement of the composite was systematically clarified. The results showed alkali treatment efficiently removed silica particles and cuticles on the fiber surface and produced windmill palm fiber with relatively high Young’s modulus and tensile strength (increased by 167.07% and 26.52%, respectively). After HVEF treatment, the increase of surface-active groups (- OH and - CHO) led to the increase of surface oxidation degree and water contact angle of WPF. Under the synergistic effect of acid/alkali pretreatment and HVEF, the interfacial properties between the adhesive and WPF were improved. This study showed that the synergistic effect of acid/alkali pretreatment and HVEF not only broaden the application scope of WPF, but also provide insights into the engineering of LVL production.

Carrot (Daucus carota L.) Seed Germination Was Promoted by Hydro-Electro Hybrid Priming Through Regulating the Accumulation of Proteins Involved in Carbohydrate and Protein Metabolism.

Asynchronized and non-uniform seed germination is causing obstacles to the large-scale cultivation of carrot (Daucus carota L.). In the present study, the combination of high voltage electrostatic field treatment (EF) with hydropriming (HYD), namely hydro-electro hybrid priming (HEHP), significantly improved all germination indicators of carrot seeds, and the promoting effect was superior to that of the HYD treatment. A tandem mass tags (TMT)-based proteomic analysis identified 4,936 proteins from the seeds, and the maximum number of differentially abundant proteins (DAPs) appeared between CK and HEHP. KEGG analysis revealed that the upregulated DAPs were mainly enriched in the pathways related to protein synthesis and degradation such as “ribosome” and “proteasome,” while the downregulated DAPs were mainly enriched in photosynthesis-related pathways. Furthermore, the maximum DAPs were annotated in carbohydrate metabolism. Some proteins identified as key enzymes of the glyoxylate cycle, the tricarboxylate cycle, glycolysis and the pentose phosphate pathway showed enhanced abundance in priming treatments. The activities of several key enzymes involved in carbohydrate metabolism were also enhanced by the priming treatments, especially the HEHP treatment. Real-time quantitative PCR (qRT-PCR) analysis revealed that the effect of priming is mainly reflected before sowing. In conclusion, the optimal effect of HEHP is to regulate the synthesis and degradation of proteins in seeds to meet the requirements of germination and initiate the utilization of seed storage reserves and respiratory metabolism. The present work expanded the understanding of the response mechanism of carrot seed germination to priming and the biological effects of high voltage electrostatic field.

Influence of high-voltage electric field thawing on frozen tilapia fillets quality

In the food sector, high voltage electric field (HVEF) has recently been regarded as a novel thawing technique. The variance in the quality was compared between frozen tilapia fish fillets thawed by high voltage electrostatic field (HVE) and those thawed conventionally as control. Frozen tilapia fish fillets were thawed under HVEF and were exposed to three different corona voltages from 4.5 to 14 kV at electrode gaps of 3, 4.5, and 6 cm; the control was thawed at 20°C without HVEF treatment. Thawing rate, evaporation, thawing, and drip losses, as well as total volatile binding nitrogen (TVB-N), thiobarbituric acid reactive substances, protein solubility, and color variations, have been employed as the quality indicators. The results revealed that thawing under HVEF greatly enhances the thawing rates of frozen tilapia fish fillets. The greatest rate of thawing was 2.16 times that of the control specimen. However, thawing HVEF reduced the protein solubility and color of fish specimens. In comparison to the control, increasing the applied voltage reduced the protein solubility of the fish specimens High electrostatic field intensities caused frozen tilapia fish fillets to oxidize quicker than lower ones.

High Permeability of Boron along the Transverse Direction of Wood under High-Voltage Electrostatic Field (HVEF) Treatment

Permeability of wood preservative is one of the most significant factors for protection of wood construction. Anisotropic flow permeability was involved in different directions of wood with higher flow resistance in the transverse and lower longitudinal directions. In this study, boron acid solution was brushed onto the tangential section of air-dried wood cubes and boron penetration along wood transverse direction was investigated under free diffusion, vacuum and HVEF treatments. Multi-scale boron distribution, FTIR measurement, leaching property, mechanical properties and fungistatic characteristic were investigated for free diffusion, vacuum and HVEF treated samples respectively. The results revealed that boron exhibited high permeability along the transverse direction with the penetration depth of ≈35 mm for HVEF treated samples and ≈1 mm for free diffusion and vacuum treated samples. For HVEF treated samples, no significant decrease of hardness, compression modulus of elasticity and strength were found in the treated samples. Better fungistatic characteristic was showcased in HVEF treated samples exposed to white rot fungi. Thus, HVEF treatment has a positive effect on boron permeability and the improvement of penetration depth of preservatives hence playing a significant role in wood protection and prolonging the service life of wood construction.

Concept Design of a High-Voltage Electrostatic Sanitizer to Prevent Spread of COVID-19 Coronavirus

In addition to public health measures, including social distancing, masking, cleaning, surface disinfection, etc., ventilation and air filtration can be a key component of a multi-pronged risk mitigation strategy against COVID-19 transmission indoors. Electrostatic precipitators (ESP) have already proved their high performance in fluid filtration, particularly in industrial applications, to control exhaust gas emissions and remove fine and superfine particles from the flowing gas, using high-voltage electrostatic fields and forces. In this contribution, a high-voltage electrostatic sanitizer (ESS), based on the electrostatic precipitation concept, is proposed as a supportive measure to reduce indoor air infection and prevent the spread of COVID-19 coronavirus. The finite element method (FEM) is used to model and simulate the proposed ESS, taking into account three main mechanisms involving in electrostatic sanitization, namely electrostatic field, airflow, and aerosol charging and tracing, which are mutually coupled to each other and occur simultaneously during the sanitization process. To consider the capability of the designed ESS in capturing superfine particles, functional parameters of the developed ESS, such as air velocity, electric potential, and space charge density, inside the ESS are investigated using the developed FEM model. Simulation results demonstrate the ability of the designed ESS in capturing aerosols containing coronavirus, precipitating suspended viral particles, and trapping them in oppositely charged electrode plates.

A Review on the Modified Atmosphere Preservation of Fruits and Vegetables with Cutting-Edge Technologies

Respiration and microbial infection are important causes of postharvest spoilage of fruits and vegetables (F&amp;V). Atmosphere storage technology can significantly reduce postharvest losses. This comprehensive review aims to cover recent progress in the application of atmosphere storage to F&amp;V preservation, not only focusing on the effect of gas conditions but also evaluating combination applications involving newer preservation technologies, including ethylene scavengers, high-pressure and decompression technology, ozone, ultraviolet radiation, active packaging, high-voltage electrostatic field, plasma treatment, and pulse-controlled atmosphere. Appropriate choice of storage conditions optimal for each F&amp;V is essential since the physiological properties and sensory qualities are affected by them. The combination of atmosphere storage with these emerging technologies could contribute to significant reductions in food loss during storage.

Effect of fouling resistance in heat exchanger and the crystal form of CaCO3 in hard circulating cooling water with electrostatic field and alternating current electric field.

The effect of high voltage electrostatic field and high voltage alternating current electric field on the heat exchanger surface fouling under the conditions of hard water was investigated. The Ca2+ concentration in two water conditions was 12 mmol/L. The Mg2+ concentration was 10 mmol/L and 12 mmol/L respectively. The HCO3- concentration changed with the Mg2+ concentration. X-ray diffraction and scanning electron microscope results confirmed that the main crystal phases of the scale samples consisted of calcite and aragonite. The high voltage electrostatic treatment can promote scale growth under both water quality conditions. However, the high voltage alternating current electric field treatment shows a good scale inhibition effect under both water quality conditions, and the scale inhibition effect is best when both Ca2+ and Mg2+ concentrations are 12 mmol/L, and the average scale inhibition rate reaches 47.58%. When the calcite content of the scale sample is significantly higher than that of aragonite, Mg2+ affects the growth and solubility of crystals. Conversely, the high voltage alternating current electric field treatment can effectively extend the fouling induction period of the adherent scale on the heat exchanger surface, which is favorable for heat exchanger fouling.

Browning inhibition on fresh-cut potatoes by high voltage electrostatic field (HVEF) pre-treatment

Browning inhibition on fresh-cut potatoes by high voltage electrostatic field (HVEF) pre-treatment

A continuous high voltage electrostatic field system for thawing food materials

A laboratory continuous high voltage electrostatic field thawing system was designed and constructed in accordance with standards for food machinery. A corona discharge in wire-plate electrodes was considered for the system and a stainless-steel sheet was utilized as conveyor belt. A corona flow was created by using high voltage of 15, 20, and 25 kV and electrode gaps of 6, 8, and 10 cm. To evaluate the system, frozen tylose MH4000 gel with a moisture content of 77% w.b. as a meat analog was thawed from –10 to 0°C. The thawing duration, which was mostly aimed at increasing the temperature of a control sample (no electrostatic field), considerably decreased when the gel was thawed in the presence of high voltage. High voltage and electrode gap showed a significant effect on both thawing duration and specific energy consumption (P˂0.0001). The thawing duration decreased significantly by decreasing the electrode gap and increasing the applied voltage. In terms of energy consumption, the best condition (minimum specific energy consumption of 10.33 kJ kg–1) was obtained for 15 kV, and an electrode gap of 10 cm.

Femtosecond laser micromachining of thin-film coatings in a high-voltage electrostatic field

The work is devoted to the problem of forming micro- and nanoscale elements topologies of high-resolution by means of controlled treatment of material surface with ultrashort laser pulses. The technology of processing thin-film coatings by the method of selective laser ablation is described. The possibility of using a high-voltage electrostatic field for collecting ablation products and preventing their deposition on the surface of formed microstructures is shown.