This paper presents an improved method for reducing radar cross-section (RCS) using dielectric-barrier-discharge (DBD) air plasma. By integrating a patterned dielectric layer in the region where ...plasma is generated, the effective permittivity is increased. This leads to higher electron density and induces a higher power absorption, enhancing the RCS reduction without altering the plasma generation conditions, such as bias voltage or gas. With an optimally designed dielectric pattern, the experimental results for a 200×200 mm 2 conductor plate show a 1.2-fold increase in absorbed power, resulting in up to 34.7 dB of RCS reduction in the 8.0-10.0 GHz range, which is a 10.7 dB improvement compared to without the patterned dielectric. This technique has achieved the largest RCS reduction reported so far for plasma-based methods, establishing it as one of the most effective approaches for RCS reduction.
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•Status of catalytic DBD-DRM is overviewed.•Recent progress in catalyst for DBD plasma DRM is elucidated.•Challenges in catalytic-DBD reactor configuration, reaction kinetics and ...fluid modelling are discussed.•Future perspectives in catalyst- DBD reactor is presented.
Dry reforming of methane (DRM) is one of the attractive methods for the utilisation of greenhouse gases (e.g., CH4, CO2) to produce valuable fuels. In the quest for an efficient development in DRM, several technologies have been practised, while dielectric barrier discharge (DBD) cold plasma technology garners special attention in the utilisation of CO2 and CH4 through DRM process due to easy upscaling opportunities and mild operating conditions. However, the low energy efficiency (EE) of DBD plasma is a distinct challenge and it offers an in-depth insight into its basic operational understandings. This review presents the overall status and current developments in DBD plasma for DRM. In the mainstream, challenges in DBD plasma technology, catalyst-plasma interactions and developments in plasma catalysts to improve the yield and selectivity of DRM have been discussed. The current status and developments in DBD reactor configuration based on reactor geometry, such as the electrode morphology, discharge gap (Dgap), discharge volume (VD) and material packing to maximise the productivity of DRM are specifically investigated. The effects of the operating parameters, such as gas hourly space velocity (GHSV), specific input energy (SIE) and feed ratio are critical for product distribution. The current status of reaction kinetics and prospects in fluid modelling of catalytic DBD plasma DRM reactor is reviewed to understand the underlying reaction mechanism. Finally, further advancements in the catalytic DBD plasma DRM has become a requisite to make it commercially viable for the successful production of valuable fuels.
Dielectric barrier discharge (DBD) is the most efficient way used in industry for ozone generation. In the last decades, many papers were published on such DBD-based ozone generators. Several ...geometric configurations can be used to generate ozone. They can be classified into two types depending on the discharge form: volume DBD, which is the common one in ozone industry, and surface DBD. Many studies have been conducted to analyze the ozone generation efficiency of both reactors to get maximum ozone production with the lowest possible power consumption. The aim of this paper is to carry out an experimental analysis of a patent-pending new reactor, of hybrid configuration, in which occur simultaneously a volume and a surface DBD. The hybrid reactor comprises a ground stainless steel cylindrical electrode, within which is placed a glass tube separated by an interval of 1 mm in which the volume DBD occurs. A second mesh stainless steel electrode connected to the high voltage is placed inside the glass tube wherein the surface discharge occurs. The obtained results showed a clear superiority of the hybrid reactor compared with both volume and surface DBD in terms of the ozone concentration. The difference in the ozone concentration reaches up to 50% compared with the volume DBD and 30% compared with the surface DBD.
Impact of dielectric barrier discharge high‐voltage cold atmospheric plasma (DBD‐HVCAP) generated with the mixture of oxygen and argon (10:90) for various treatment times (2.5 to 10 min) on the ...qualities of Asian sea bass slices during 4 °C storage was investigated. Microbial load of slices treated with DBD‐HVCAP were lower than the control. The efficacy of bacteria reduction by DBD‐HVCAP was dependent on the treatment times (P < 0.05). Total viable bacteria count (TVBC) was more than 6.0 Log CFU/g at day 6 for the control kept in air. Slices treated with DBD‐HVCAP for all treatment times used had TVBC lower than the limit at day 12. Total volatile nitrogen base content (TVNB) as well as trimethylamine (TMA) content in slices treated with DBD‐HVCAP were lower than that of the control throughout the storage. TVNB as well as TMA contents were lower in HVCAP treated slices in a treatment time‐dependent manner. Nevertheless, lipid oxidation in samples treated with DBD‐HVCAP was higher than that of the control. Polyunsaturated fatty acids were decreased in slices treated with DBD‐HVCAP for more than 5 min after 12 days of storage. Therefore DBD‐HVCAP treatment for 5 min was demonstrated to be potential means for increasing the shelf‐life of Asian sea bass slices with minimal negative effect on chemical and sensory properties, in which they could be stored longer than 12 days at 4 °C.
Practical Application
Microbial inactivation capacity of dielectric barrier discharge high‐voltage cold atmospheric plasma (DBD‐HVCAP) has been documented with limited information on its application in extending the shelf‐life of foods. DBD‐HVCAP was demonstrated as an innovative technology for extending the shelf‐life of Asian sea bass slices, which could be implemented in seafood industries for assuring safety and extending shelf‐life of products. The shelf‐life of the slices treated with DBD‐HVCAP was extended to 12 days of storage at 4 °C as compared to the 6 days of the untreated counterpart.
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•The history, microdischarge formation and application of DBD were presented.•The effect of reactor structure, power supplies, packing materials and gas properties on VOCs removal ...were described.•The discussion of the above factors was based on discharge behaviors, VOCs removal and mineralization rate, and by-products.•The practical implementation of DBD in VOCs abatement were examined.•Future trends on DBD for VOCs treatment were given.
This review describes the history and current status of dielectric barrier discharge (DBD) non-thermal plasma (NTP) for volatile organic compounds (VOCs) abatement. Firstly, the history of DBD, the formation of microdischarge and its environmental applications were presented. Next, the status quo of DBD for VOCs removal was discussed in detail from four aspects: reactor structure (include electrode material and configuration, discharge gap and length, dielectric material and thickness, and number of dielectrics), power supplies (include applied voltage, frequency and pulsed power supply), packing materials (include packed position, properties of packing material, loaded catalyst on support and synergy of plasma and catalysis) and gas properties (include target reactants, gas flow rate, initial concentration, oxygen content and humidity level). The description of these factors is mainly based on their effects on discharge characteristics and VOCs decomposition in DBD. Subsequently, a number of aspects related to the practical implementation of DBD for VOCs treatment were described. Finally, future trends were suggested based on the existing research works.
Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO2 conversion into value-added chemicals and fuels, N2 fixation for the synthesis of NH3 or NOx, ...methane conversion into higher hydrocarbons or oxygenates. It is also widely used for air pollution control (e.g., VOC remediation). Plasma catalysis allows thermodynamically difficult reactions to proceed at ambient pressure and temperature, due to activation of the gas molecules by energetic electrons created in the plasma. However, plasma is very reactive but not selective, and thus a catalyst is needed to improve the selectivity.
In spite of the growing interest in plasma catalysis, the underlying mechanisms of the (possible) synergy between plasma and catalyst are not yet fully understood. Indeed, plasma catalysis is quite complicated, as the plasma will affect the catalyst and vice versa. Moreover, due to the reactive plasma environment, the most suitable catalysts will probably be different from thermal catalysts. More research is needed to better understand the plasma–catalyst interactions, in order to further improve the applications.
Corn starch was treated by a dielectric barrier discharge plasma, and the changes in the granule morphology, crystalline structure, and molecular structure, as well as the rheological properties, ...were investigated using diverse techniques. Dielectric barrier discharge plasma could change not only the granule surface but also the internal structures of the starch granule through its pinholes. Specifically, after the plasma treatment, as the pinhole diameter increased, the relative degree of crystallinity decreased, accompanied by molecular chain oxidation, i.e., the generation of carboxyl groups, and degradation, i.e., molecular weight reduction. Therefore, the rheological behavior changed from pseudo-plastic to Newtonian with a decrease in the paste viscosity. The results indicate that dielectric barrier plasma could be used to produce modified starch with low viscosity at a high concentration for food and non-food applications.
As an eco-friendly and non-thermal physical technique, dielectric barrier discharge plasma has attracted great attention in polymer modification due to the interest in reducing generated wastes during modification and producing polymer products with high safety. Starch is traditionally a main material for foods and has been widely used in food and non-food industries. For improving the properties of starch and thus widening its industrial applications using a specific technique, it is indispensible to understand how the technique affects starch's structure and property. The present work revealed that not only was the surface of starch granules altered by the dielectric barrier discharge plasma but also the internal structure was affected, since the pinholes promoted the penetration of the plasma into granule interior. In particular, along with a reduced degree of crystallinity, molecular chain oxidation and degradation occurred, as confirmed by the generation of carboxyl groups and the molecular weight reduction. Then, the rheological behavior of starch paste changed from pseudo-plastic to non-Newtonian, together with a decreased paste viscosity. These results have demonstrated that dielectric barrier discharge plasma could be used as a new physical method to modulate the structure and rheological properties of starch, for the production of starchy food products with relatively low viscosity at a high concentration.
•From a structural view, plasma effects on starch rheological property were disclosed.•Except the surface, starch granule interior was altered by plasma through pinholes.•Plasma caused molecular oxidation and degradation and reduced the crystallinity.•Plasma changed starch rheological behavior from pseudo-plastic to non-Newtonian.•Plasma is a potential technique to modulate starch rheological property.
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