Surface flashover behaviour of insulating materials under impulsive electric fields in environmentally friendly gases

2017 ◽  
Author(s):  
A. C. Mermigkas ◽  
I. V. Timoshkin ◽  
S. J. MacGregor ◽  
M. J. Given ◽  
M. P. Wilson ◽  
...  
Keyword(s):  
Electric Fields ◽  
Environmentally Friendly ◽  
Insulating Materials ◽  
Surface Flashover

scholarly journals Environmentally Friendly Techniques and Their Comparison in the Extraction of Natural Antioxidants from Green Tea, Rosemary, Clove, and Oregano

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1869
Author(s):  
Mariel Calderón-Oliver ◽  
Edith Ponce-Alquicira
Keyword(s):  
Green Tea ◽  
Electric Fields ◽  
Antioxidant Activities ◽  
Environmentally Friendly ◽  
Natural Antioxidants ◽  
Deep Eutectic Solvents ◽  
Extraction Methods ◽  
Extraction Techniques ◽  
Health Trends ◽  
Food Applications

Many current food and health trends demand the use of more ecological, sustainable, and environmentally friendly techniques for the extraction of bioactive compounds, including antioxidants. However, extraction yields and final antioxidant activities vary between sources and are highly influenced by the given extraction method and nature and ratio of the employed solvent, especially for total polyphenols, flavonoids, and anthocyanins, which are well recognized as natural antioxidants with food applications. This review focused on the most common extraction techniques and potential antioxidant activity in the food industry for various natural antioxidant sources, such as green tea, rosemary, clove, and oregano. Green extraction techniques have been proven to be far more efficient, environmentally friendly, and economical. In general, these techniques include the use of microwaves, ultrasound, high hydrostatic pressure, pulsed electric fields, enzymes, and deep eutectic solvents, among others. These extraction methods are described here, including their advantages, disadvantages, and applications.

scholarly journals Restraining Surface Charge Accumulation and Enhancing Surface Flashover Voltage through Dielectric Coating

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 750
Author(s):  
Jixing Sun ◽  
Sibo Song ◽  
Xiyu Li ◽  
Yunlong Lv ◽  
Jiayi Ren ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Transition Process ◽  
Metallic Particle ◽  
Particle Charging ◽  
Insulating Surfaces ◽  
Surface Flashover ◽  
Charging Time ◽  
The Impact

A conductive metallic particle in a gas-insulated metal-enclosed system can charge through conduction or induction and move between electrodes or on insulating surfaces, which may lead to breakdown and flashover. The charge on the metallic particle and the charging time vary depending on the spatial electric field intensity, the particle shape, and the electrode surface coating. The charged metallic particle can move between the electrodes under the influence of the spatial electric field, and it can discharge and become electrically conductive when colliding with the electrodes, thus changing its charge. This process and its factors are mainly affected by the coating condition of the colliding electrode. In addition, the interface characteristics affect the particle when it is near the insulator. The charge transition process also changes due to the electric field strength and the particle charging state. This paper explores the impact of the coating material on particle charging characteristics, movement, and discharge. Particle charging, movement, and charge transfer in DC, AC, and superimposed electric fields are summarized. Furthermore, the effects of conductive particles on discharge characteristics are compared between coated and bare electrodes. The reviewed studies demonstrate that the coating can effectively reduce particle charge and thus the probability of discharge. The presented research results can provide theoretical support and data for studying charge transfer theory and design optimization in a gas-insulated system.

scholarly journals Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

2021 ◽  
Vol 2083 (2) ◽  
pp. 022068
Author(s):  
Xiaohui Wang ◽  
Chunyan Song ◽  
Xueying Xie ◽  
Nan Zhang ◽  
Ruiqing Guo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electrode Materials ◽  
High Efficiency ◽  
Thermal Power ◽  
Cooling Water ◽  
Environmentally Friendly ◽  
Research Progress ◽  
Electrode Spacing ◽  
Experimental Conditions ◽  
Circulating Cooling Water

Abstract As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

scholarly journals Sustainable, Renewable and Environmental-Friendly Insulation Systems for High Voltages Applications

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3901
Author(s):  
Muhammad Rafiq ◽  
Muhammad Shafique ◽  
Anam Azam ◽  
Muhammad Ateeq ◽  
Israr Ahmad Khan ◽  
...  
Keyword(s):  
Environmentally Friendly ◽  
Research Trends ◽  
Substantial Part ◽  
Waste Oil ◽  
Market Place ◽  
Insulating Materials ◽  
Economic Issues ◽  
Environmental Friendly ◽  
Insulation Systems ◽  
Petroleum Oil

With the inception of high voltage (HV), requisites on the insulating permanence of HV equipment is becoming increasingly crucial. Mineral/synthetic oil liquid insulation—together with solid insulation materials (paper, pressboard)—is the fundamental insulation constituent in HV apparatuses; their insulation attributes perform a substantial part in a reliable and steady performance. Meanwhile, implications on the environment, scarcity of petroleum oil supplies and discarding complications with waste oil have stimulated investigators to steer their attention towards sustainable, renewable, biodegradable and environmentally friendly insulating substances. The contemporary insulating constituent’s evolution is driven by numerous dynamics—in particular, environmental obligations and other security and economic issues. Consequently, HV equipment manufacturers must address novel specifications concerning to these new standards. Renewable, sustainable and environmentally friendly insulating materials are continuously substituting conventional insulating items in the market place. These are favorable to traditional insulating materials, due to their superior functionality. The also offer explicit security and eco-friendly advantages. This article discusses cutting-edge technology of environmentally friendly insulating materials, including their fabrication, processing and characterization. The new renewable, insulating systems used in HV equipment are submitted and their fundamental gains stated in comparison with conventional insulating materials. Several experimental efforts carried out in various parts of the world are presented, offering an outline of the existing research conducted on renewable insulating systems. The significance of this article lies in summarizing prior investigations, classifying research essence, inducements and predicting forthcoming research trends. Furthermore, opportunities and constraints being experienced in the field of exploration are evidently reported. Last but not least, imminent research proposals and applications are recommended.

scholarly journals Hemp-Straw Composites: Gluing Study and Multi-Physical Characterizations

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1199 ◽  
Author(s):  
Marie Viel ◽  
Florence Collet ◽  
Sylvie Prétot ◽  
Christophe Lanos
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Sustainable Development ◽  
Wheat Straw ◽  
Feasibility Study ◽  
Building Materials ◽  
Environmentally Friendly ◽  
Insulating Materials ◽  
Low Thermal Conductivity

In order to meet the requirement of sustainable development, building materials are increasingly environmentally friendly. They can be partially or fully bio-based or recycled. This paper looks at the development of fully bio-based composites where agro-resources are valued as bio-based aggregates (hemp) and as binding materials (wheat). In a previous work, a feasibility study simultaneously investigated the processing and ratio of wheat straw required to ensure a gluing effect. In this paper, three kinds of hemp-straw composites are selected and compared with a hemp-polysaccharides composite. The gluing effect is analyzed chemically and via SEM. The developed composites were characterized multi-physically. They showed sufficiently high mechanical properties to be used as insulating materials. Furthermore, they showed good thermal performances with a low thermal conductivity (67.9–69.0 mW/(m · K) at 23 ° C, dry).

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