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14 pages, 11889 KiB

Open AccessArticle

Thermal Propagation Test Bench for the Study of the Paschen Curve and Lightning Arcs of Venting Gas

by Björn Mulder, Kai Peter Birke, Björn Obry, Stefan Wigger, Ruslan Kozakov, Pavel Smirnov and Jochen Schein

Batteries 2024, 10(11), 397; https://doi.org/10.3390/batteries10110397 - 8 Nov 2024

Viewed by 1998

Abstract

Thermal propagation events are characterized by fire and thick black smoke, leading to propagation methods with a focus on preventing heat transfer and optimizing gas flow. Yet little attention is being paid to the electric conductivity of the gas, leading to possibly unexpected battery casing openings due to lightning arcs as well as potentially providing the minimum ignition energy. This gas composition (omitting particles) was used at different temperatures and pressures in a lightning arc test bench, leading to the Paschen curve. Using a mini-module cell setup, filtered venting gas was flowed through another lightning arc test bench, allowing for in situ measurements. Full article

(This article belongs to the Special Issue Advances in Lithium-Ion Battery Safety and Fire)

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14 pages, 8922 KiB

Open AccessArticle

Enabling High-Power Conditioning and High-Voltage Bus Integration Using Series-Connected DC Transformers in Spacecrafts

by Carlos Orts, Ausiàs Garrigós, David Marroquí, Antxon Arrizabalaga and Andreas Franke

Aerospace 2024, 11(8), 690; https://doi.org/10.3390/aerospace11080690 - 21 Aug 2024

Cited by 1 | Viewed by 1573

Abstract

This article proposes a photovoltaic power processor for high-voltage and high-power distribution bus, between 300 V and 900 V, to be used in future space platforms like large space stations or lunar bases. Solar arrays with voltages higher than 100 V are not available for space application, being necessary to apply power conversion techniques. The idea behind this is to use series-connected zero-voltage and zero-current unregulated and isolated DC converters to achieve high bus voltage from the existing solar arrays. Bus regulation is then achieved through low-frequency hysteretic control. Topology description, semiconductor selection, design procedure, simulation and experimental validation, including tests in vacuum and partial pressures, are presented. Full article

(This article belongs to the Special Issue Advanced Spacecraft/Satellite Technologies)

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19 pages, 7960 KiB

Open AccessArticle

The Simulation of Dielectric Barrier Discharge for Breakdown Voltage in Starch Modification

by Pitchasak Chankuson, Paramee Chumsri and Apinun Plodkaew

Appl. Sci. 2023, 13(22), 12143; https://doi.org/10.3390/app132212143 - 8 Nov 2023

Cited by 4 | Viewed by 1942

Abstract

This paper presents the simulation results for dielectric barrier discharge (DBD) at atmospheric pressure in argon gas for different relative permittivity, granule shape, thickness layer, and granule diameter measurements for starch on the breakdown voltage. DBD is commonly utilized to generate cold plasma for starch modification. The electric field was computed using COMSOL Multiphysics 5.3a software. The breakdown voltage was calculated employing Paschen’s law for this electric field. The voltage was found according to the breakdown criterion for gap distance 0.2–1.0 cm, and then the Paschen curve could be plotted. The results show that the top electrode of the plasma system may be replaced with the parallel plate electrode by a mesh electrode with a bigger mesh size to achieve a lower breakdown voltage. In addition, increasing the relative permittivity and decreasing the thickness layer can reduce the applied voltage for plasma formation. When compared to the sphere and ellipsoid shapes, starch with a polyhedral granule shape requires a significantly lower voltage for breakdown. The starch granule diameter does not affect the breakdown voltage. These findings can be utilized to determine the optimal breakdown voltage for each type of starch modification, contributing to the construction of a high-efficiency plasma production system for starch modification. Full article

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8 pages, 1936 KiB

Open AccessArticle

An On-Chip Microscale Vacuum Chamber with High Sealing Performance Using Graphene as Lateral Feedthrough

by Panpan Yu, Fangyuan Zhan, Weidong Rao, Yanqing Zhao, Zheng Fang, Zidong Tu, Zhiwei Li, Dengzhu Guo and Xianlong Wei

Micromachines 2023, 14(1), 84; https://doi.org/10.3390/mi14010084 - 29 Dec 2022

Cited by 2 | Viewed by 2131

Abstract

On-chip microscale vacuum chambers with high sealing performance and electrical feedthroughs are highly desired for microscale vacuum electronic devices and other MEMS devices. In this paper, we report an on-chip microscale vacuum chamber which achieves a high sealing performance by using monolayer graphene as lateral electrical feedthrough. A vacuum chamber with the dimensions of π × 2 mm × 2 mm × 0.5 mm is fabricated by anodically bonding a glass chip with a through-hole between two Si chips in a vacuum, after monolayer graphene electrodes have been transferred to the surface of one of the Si chips. Benefiting from the atomic thickness of monolayer graphene, the leak rate of Si–glass bonding interface with a monolayer graphene feedthrough is measured at less than 2 × 10⁻¹¹ Pa·m³/s. The monolayer graphene feedthrough exhibits a minor resistance increase from 22.5 Ω to 31 Ω after anodic bonding, showing good electrical conductance. The pressure of the vacuum chamber is estimated to be 185 Pa by measuring the breakdown voltage. Such a vacuum is found to maintain for more than 50 days without obvious degradation, implying a high sealing performance with a leak rate of less than 1.02 × 10⁻¹⁶ Pa·m³/s. Full article

(This article belongs to the Special Issue On-Chip Electron Emission and Related Devices)

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11 pages, 119 KiB

Open AccessArticle

CNT Sensors for Detecting Gases with Low Adsorption Energy by Ionization

by Seongjeen Kim

Sensors 2006, 6(5), 503-513; https://doi.org/10.3390/s6050503 - 5 May 2006

Cited by 64 | Viewed by 11948

Abstract

In case of typical chemical gas sensors reacted by gas adsorption on surface of anactive layer, it is difficult to detect some gases which have low chemical adsorption energylike inert gases. In this paper, we report a gas sensor using carbon nanotube(CNT) array aselectron emitters for the purpose of detecting these gases. Specifically, sensors werefabricated with applications of glass patterning by a sand-blast process and of anodicbonding between glass and silicon to improve the compactness of the structure and thereliability in process. The proposed sensor, based on an electrical discharge theory known asPaschen's law, worked by figuring the changes of dark discharge current and initialbreakdown voltage depending on the concentration and the identity of gases. In this work,air and Ar gases were examined and discussed. Full article

(This article belongs to the Special Issue Gas Sensors)

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