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Keywords = warm atmospheric plasma

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17 pages, 2031 KiB  
Article
Geochemical Characteristics and Paleoenvironmental Significance of the Xishanyao Formation Coal from the Xiheishan Mining Area, Zhundong Coalfield, Xinjiang, China
by Yongjie Hou, Kaixuan Zhang, Xiangcheng Jin, Yongjia Xu, Xiaotao Xu and Xiaoyun Yan
Minerals 2025, 15(7), 686; https://doi.org/10.3390/min15070686 - 27 Jun 2025
Viewed by 258
Abstract
The eastern Junggar Basin in Xinjiang, China is a key coal-bearing region dominated by the Middle Jurassic Xishanyao Formation. Despite its significance as a major coal resource base, detailed paleoenvironmental reconstructions of its coal seams remain limited. This study investigates the B1 [...] Read more.
The eastern Junggar Basin in Xinjiang, China is a key coal-bearing region dominated by the Middle Jurassic Xishanyao Formation. Despite its significance as a major coal resource base, detailed paleoenvironmental reconstructions of its coal seams remain limited. This study investigates the B1, B2, B3, and B5 coal seams of the Xishanyao Formation using X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to assess geochemical indicators of the depositional environment during coal formation. The results show that the coal samples are characterized by high inertinite content and low vitrinite reflectance, indicative of low-rank coal. Slight enrichment of strontium (Sr) was observed in the B1, B2, and B5 seams, while cobalt (Co) showed minor enrichment in B3. Redox-sensitive elemental ratios (Ni/Co, V/Cr, and Mo) suggest that the peat-forming environment ranged from oxidizing to dysoxic conditions, with relatively high oxygen availability and strong hydrodynamic activity. A vertical trend of increasing paleosalinity and a shift from warm–humid to dry–hot paleoclimatic conditions was identified from the lower (B1) to upper (B5) coal seams. Additionally, the estimated atmospheric oxygen concentration during the Middle Jurassic was approximately 28.4%, well above the threshold for wildfire combustion. These findings provide new insights into the paleoenvironmental evolution of the Xishanyao Formation and offer a valuable geochemical framework for coal exploration and the assessment of coal-associated mineral resources in the eastern Junggar Basin. Full article
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12 pages, 2719 KiB  
Article
The Atmospheric Chemistry of Fluoroacetonitrile and the Characterization of the Major Product, Cyanoformyl Fluoride
by Ramesh Sapkota, Trang Nguyen and Paul Marshall
Molecules 2025, 30(3), 478; https://doi.org/10.3390/molecules30030478 - 22 Jan 2025
Viewed by 6432
Abstract
Fluorinated nitriles have been proposed as low-global-warming-potential substitutes for industrial applications such as plasma etching and as dielectric materials in high-voltage equipment. FT-IR spectroscopy was used to measure the radiative efficiency of CH2FCN and its reactivity towards Cl and OH radicals, [...] Read more.
Fluorinated nitriles have been proposed as low-global-warming-potential substitutes for industrial applications such as plasma etching and as dielectric materials in high-voltage equipment. FT-IR spectroscopy was used to measure the radiative efficiency of CH2FCN and its reactivity towards Cl and OH radicals, and to determine products from the Cl reaction. Relative rate experiments yielded rate constants for Cl and OH reactions of (2.1 ± 0.3) × 10−14 and (7.0 ± 1.0) × 10−14 cm3 molecule−1 s−1, respectively. The estimated atmospheric lifetime of CH2FCN with respect to radical attack was estimated to be 0.45 years, which, combined with the radiative efficiency of 0.042 W m−2 ppb−1, implies a 100-year global warming potential of 20. FCOCN was observed as the only organic product of the Cl-atom reaction in air, consistent with a dominant role for H-abstraction. Absolute infrared cross-sections for FCOCN were determined, to assist future experiments where this molecule may be formed. Quantum calculations at the CBS-APNO//B2PLYP-D3/cc-pVTZ level indicate similar energy barriers to addition and abstraction for OH radical attack, but the looser transition state and greater opportunity for tunneling also favor abstraction in this case. Full article
(This article belongs to the Section Physical Chemistry)
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17 pages, 1665 KiB  
Article
Impacts of the Sudden Stratospheric Warming on Equatorial Plasma Bubbles: Suppression of EPBs and Quasi-6-Day Oscillations
by Ercha Aa, Nicholas M. Pedatella and Guiping Liu
Remote Sens. 2024, 16(8), 1469; https://doi.org/10.3390/rs16081469 - 21 Apr 2024
Cited by 1 | Viewed by 1598
Abstract
This study investigates the day-to-day variability of equatorial plasma bubbles (EPBs) over the Atlantic–American region and their connections to atmospheric planetary waves during the sudden stratospheric warming (SSW) event of 2021. The investigation is conducted on the basis of the GOLD (Global Observations [...] Read more.
This study investigates the day-to-day variability of equatorial plasma bubbles (EPBs) over the Atlantic–American region and their connections to atmospheric planetary waves during the sudden stratospheric warming (SSW) event of 2021. The investigation is conducted on the basis of the GOLD (Global Observations of the Limb and Disk) observations, the ICON (Ionospheric Connection Explorer) neutral wind dataset, ionosonde measurements, and simulations from the WACCM-X (Whole Atmosphere Community Climate Model with thermosphere–ionosphere eXtension). We found that the intensity of EPBs was notably reduced by 35% during the SSW compared with the non-SSW period. Furthermore, GOLD observations and ionosonde data show that significant quasi-6-day oscillation (Q6DO) was observed in both the intensity of EPBs and the localized growth rate of Rayleigh–Taylor (R-T) instability during the 2021 SSW event. The analysis of WACCM-X simulations and ICON neutral winds reveals that the Q6DO pattern coincided with an amplification of the quasi-6-day wave (Q6DW) in WACCM-X simulations and noticeable ∼6-day periodicity in ICON zonal winds. The combination of these multi-instrument observations and numerical simulations demonstrates that certain planetary waves like the Q6DW can significantly influence the day-to-day variability of EPBs, especially during the SSW period, through modulating the strength of prereversal enhancement and the growth rate of R-T instability via the wind-driven dynamo. These findings provide novel insights into the connection between atmospheric planetary waves and ionospheric EPBs. Full article
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16 pages, 3884 KiB  
Article
Greenhouse Gas Conversion into Hydrocarbons and Oxygenates Using Low Temperature Barrier Discharge Plasma Combined with Zeolite Catalysts
by Oleg V. Golubev, Dmitry E. Tsaplin and Anton L. Maximov
Gases 2023, 3(4), 165-180; https://doi.org/10.3390/gases3040012 - 5 Dec 2023
Viewed by 1963
Abstract
Global warming occurs as a result of the build-up of greenhouse gases in the atmosphere, causing an increase in Earth’s average temperature. Two major greenhouse gases (CH4 and CO2) can be simultaneously converted into value-added chemicals and fuels thereby decreasing [...] Read more.
Global warming occurs as a result of the build-up of greenhouse gases in the atmosphere, causing an increase in Earth’s average temperature. Two major greenhouse gases (CH4 and CO2) can be simultaneously converted into value-added chemicals and fuels thereby decreasing their negative impact on the climate. In the present work, we used a plasma-catalytic approach for the conversion of methane and carbon dioxide into syngas, hydrocarbons, and oxygenates. For this purpose, CuCe zeolite-containing catalysts were prepared and characterized (low-temperature N2 adsorption, XRF, XRD, CO2-TPD, NH3-TPD, TPR). The process of carbon dioxide methane reforming was conducted in a dielectric barrier discharge under atmospheric pressure and at low temperature (under 120 °C). It was found that under the studied conditions, the major byproducts of CH4 reforming are CO, H2, and C2H6 with the additional formation of methanol and acetone. The application of a ZSM-12 based catalyst was beneficial as the CH4 conversion increased and the total concentration of liquid products was the highest, which is related to the acidic properties of the catalyst. Full article
(This article belongs to the Section Gas Emissions)
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14 pages, 3621 KiB  
Article
Reducing Storage Losses of Organic Apples by Plasma Processed Air (PPA)
by Robert Wagner, Thomas Weihe, Hauke Winter, Christoph Weit, Jörg Ehlbeck and Uta Schnabel
Appl. Sci. 2023, 13(23), 12654; https://doi.org/10.3390/app132312654 - 24 Nov 2023
Cited by 2 | Viewed by 1412
Abstract
The consumer demand for organic food including apples is increasing worldwide. Despite favorable environmental and health benefits, organic farming bears also disadvantages like high amounts of fruit losses due to storage rot. A novel treatment with plasma-processed air (PPA) to sanitize organic apples [...] Read more.
The consumer demand for organic food including apples is increasing worldwide. Despite favorable environmental and health benefits, organic farming bears also disadvantages like high amounts of fruit losses due to storage rot. A novel treatment with plasma-processed air (PPA) to sanitize organic apples is investigated. The plasma source for the generation of PPA was operated at a frequency of 2.45 GHz, a power output of 1.1 kW and a gas flow of 18 standard liters per minute. The antimicrobial efficiency of the PPA was tested on the natural load of organic apples (cultivar Natyra) with a load ranging from 104 to 106 CFU/mL in an experimental laboratory setup. A larger application was applied on artificially inoculated (Pseudomonas fluorescens~108 CFU/mL and Pezicula malicorticis~106 CFU/mL) organic apples to test the up-scalability of the PPA treatment. The apples were photographically documented and their texture was analyzed during the 26-day storage phase to investigate the influence of the PPA treatment on the appearance of the apples. The laboratory experiments resulted in a log10-reduction of one to two log10 levels compared to untreated and compressed-air-treated apples. For apples inoculated with P. fluorescens, the up-scaled procedure resulted in up to four levels of log10 reduction. In apples inoculated with P. malicorticis, the up-scaled procedure resulted in no reduction. This indicates that the application of PPA to organic apples can be effective for bacteria but needs to be optimized for fungi. Therefore, further testing is needed to validate the results. Full article
(This article belongs to the Special Issue Microorganisms in Foods and Food Processing Environments)
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109 pages, 17939 KiB  
Review
Hydrogen, Ammonia and Symbiotic/Smart Fertilizer Production Using Renewable Feedstock and CO2 Utilization through Catalytic Processes and Nonthermal Plasma with Novel Catalysts and In Situ Reactive Separation: A Roadmap for Sustainable and Innovation-Based Technology
by Galip Akay
Catalysts 2023, 13(9), 1287; https://doi.org/10.3390/catal13091287 - 8 Sep 2023
Cited by 14 | Viewed by 6546
Abstract
This multi-disciplinary paper aims to provide a roadmap for the development of an integrated, process-intensified technology for the production of H2, NH3 and NH3-based symbiotic/smart fertilizers (referred to as target products) from renewable feedstock with CO2 sequestration [...] Read more.
This multi-disciplinary paper aims to provide a roadmap for the development of an integrated, process-intensified technology for the production of H2, NH3 and NH3-based symbiotic/smart fertilizers (referred to as target products) from renewable feedstock with CO2 sequestration and utilization while addressing environmental issues relating to the emerging Food, Energy and Water shortages as a result of global warming. The paper also discloses several novel processes, reactors and catalysts. In addition to the process intensification character of the processes used and reactors designed in this study, they also deliver novel or superior products so as to lower both capital and processing costs. The critical elements of the proposed technology in the sustainable production of the target products are examined under three-sections: (1) Materials: They include natural or synthetic porous water absorbents for NH3 sequestration and symbiotic and smart fertilizers (S-fertilizers), synthesis of plasma interactive supported catalysts including supported piezoelectric catalysts, supported high-entropy catalysts, plasma generating-chemical looping and natural catalysts and catalysts based on quantum effects in plasma. Their performance in NH3 synthesis and CO2 conversion to CO as well as the direct conversion of syngas to NH3 and NH3—fertilizers are evaluated, and their mechanisms investigated. The plasma-generating chemical-looping catalysts (Catalysts, 2020, 10, 152; and 2016, 6, 80) were further modified to obtain a highly active piezoelectric catalyst with high levels of chemical and morphological heterogeneity. In particular, the mechanism of structure formation in the catalysts BaTi1−rMrO3−x−y{#}xNz and M3O4−x−y{#}xNz/Si = X was studied. Here, z = 2y/3, {#} represents an oxygen vacancy and M is a transition metal catalyst. (2) Intensified processes: They include, multi-oxidant (air, oxygen, CO2 and water) fueled catalytic biomass/waste gasification for the generation of hydrogen-enriched syngas (H2, CO, CO2, CH4, N2); plasma enhanced syngas cleaning with ca. 99% tar removal; direct syngas-to-NH3 based fertilizer conversion using catalytic plasma with CO2 sequestration and microwave energized packed bed flow reactors with in situ reactive separation; CO2 conversion to CO with BaTiO3−x{#}x or biochar to achieve in situ O2 sequestration leading to higher CO2 conversion, biochar upgrading for agricultural applications; NH3 sequestration with CO2 and urea synthesis. (3) Reactors: Several patented process-intensified novel reactors were described and utilized. They are all based on the Multi-Reaction Zone Reactor (M-RZR) concept and include, a multi-oxidant gasifier, syngas cleaning reactor, NH3 and fertilizer production reactors with in situ NH3 sequestration with mineral acids or CO2. The approach adopted for the design of the critical reactors is to use the critical materials (including natural catalysts and soil additives) in order to enhance intensified H2 and NH3 production. Ultimately, they become an essential part of the S-fertilizer system, providing efficient fertilizer use and enhanced crop yield, especially under water and nutrient stress. These critical processes and reactors are based on a process intensification philosophy where critical materials are utilized in the acceleration of the reactions including NH3 production and carbon dioxide reduction. When compared with the current NH3 production technology (Haber–Bosch process), the proposed technology achieves higher ammonia conversion at much lower temperatures and atmospheric pressure while eliminating the costly NH3 separation process through in situ reactive separation, which results in the production of S-fertilizers or H2 or urea precursor (ammonium carbamate). As such, the cost of NH3-based S-fertilizers can become competitive with small-scale distributed production platforms compared with the Haber–Bosch fertilizers. Full article
(This article belongs to the Special Issue Application of Catalysts in CO2 Capture, Production and Utilization)
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15 pages, 2091 KiB  
Article
Controlling Parameters in the Efficiency of Hydrogen Production via Electrification with Multi-Phase Plasma Processing Technology
by Shariful Islam Bhuiyan, Kunpeng Wang, Md Abdullah Hil Baky, Jamie Kraus, Howard Jemison and David Staack
Energies 2023, 16(14), 5509; https://doi.org/10.3390/en16145509 - 20 Jul 2023
Cited by 5 | Viewed by 1993
Abstract
A nanosecond pulsed non-equilibrium plasma reactor is used to crack hydrocarbons into hydrogen and lighter intermediates at atmospheric pressure and warm temperature. The effects of power, capacitance, breakdown voltage, pulsing frequency, energy per pulse, and carrier gas type are investigated for product generation. [...] Read more.
A nanosecond pulsed non-equilibrium plasma reactor is used to crack hydrocarbons into hydrogen and lighter intermediates at atmospheric pressure and warm temperature. The effects of power, capacitance, breakdown voltage, pulsing frequency, energy per pulse, and carrier gas type are investigated for product generation. Multiple gaseous products including hydrogen and hydrocarbons are calculated and compared at different conditions. A statistical analysis is performed on hydrogen yield for different experimental conditions to determine the significance of the studied parameters. Comparable hydrogen yields are produced when using methane (4 to 22 g-H2/kWh) as a carrier gas as compared to argon (7 to 14 g-H2/kWh). Although, notably, the methane carrier is more selective to hydrogen and sensitive to other operating parameters, the argon is not. Statistical analysis shows that plasma power, capacitance, and energy per pulse appear to influence hydrogen yield while pulsing frequency and breakdown voltage do not. A higher yield of hydrogen is achieved with low plasma power and a low energy per pulse, with a low capacitance for both cases of pure CH4 and pure Ar. The results show that low plasma power based on a low energy per pulse of <10 mJ is preferable for hydrogen production in a batch reactor. This CO2-free hydrogen production method produces hydrogen from fossil fuels at less than USD 2/kg in electricity. Full article
(This article belongs to the Section I3: Energy Chemistry)
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18 pages, 1305 KiB  
Review
Non-Thermal Plasma Technology for CO2 Conversion—An Overview of the Most Relevant Experimental Results and Kinetic Models
by Vera Marcantonio, Marcello De Falco and Enrico Bocci
Energies 2022, 15(20), 7790; https://doi.org/10.3390/en15207790 - 21 Oct 2022
Cited by 9 | Viewed by 3721
Abstract
Global warming, along with increasing global energy demands, has led to the need for a sustainable and low-carbon-based energy economy. In addition to renewable energy technologies, such as biomass, solar, hydro, and wind, another possible strategy to mitigate climate change is the capture/conversion [...] Read more.
Global warming, along with increasing global energy demands, has led to the need for a sustainable and low-carbon-based energy economy. In addition to renewable energy technologies, such as biomass, solar, hydro, and wind, another possible strategy to mitigate climate change is the capture/conversion and recycling of CO2. In recent years, many methods for both CO2 capture (mainly adsorption, absorption, and membrane) and conversion (many electrolysis, catalyst, and plasma) have been investigated. Conversion technology is less studied but seems to be very promising. Within that, non-thermal plasma technology has received much interest because it works at low temperatures and atmospheric pressure, and there is no need for high temperature and high electricity consumption, which are typical of the catalyst and electrolysis conversion processes, respectively. Therefore, in order to optimize this emerging technology, simulative kinetic models have been developed with the aim of maximizing both energy efficiency and CO2 conversion. In the present paper, an overview of the most common non-thermal plasma technologies was carried out to highlight the advantages and disadvantages of each method. Then, an overview of the most significant kinetic models available in literature was carried out to point out the main reactions occurring during CO2 conversion and also the parameters that most affect the performance of a plasma reactor during CO2 conversion. Then, a brief recap of the literature available on economic studies of the plasma process is given. Full article
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36 pages, 4549 KiB  
Article
The March 2012 Heat Wave in Northeast America as a Possible Effect of Strong Solar Activity and Unusual Space Plasma Interactions
by Georgios C. Anagnostopoulos, Sofia-Anna I. Menesidou and Dimitrios A. Efthymiadis
Atmosphere 2022, 13(6), 926; https://doi.org/10.3390/atmos13060926 - 7 Jun 2022
Cited by 5 | Viewed by 3342
Abstract
In the past two decades, the world has experienced an unprecedented number of extreme weather events, some causing major human suffering and economic damage. The March 2012 heat wave is one of the most known and broadly discussed events in the Northeast United [...] Read more.
In the past two decades, the world has experienced an unprecedented number of extreme weather events, some causing major human suffering and economic damage. The March 2012 heat wave is one of the most known and broadly discussed events in the Northeast United States (NE-USA). The present study examines in depth the possible influence of solar activity on the historic March 2012 heat wave based on a comparison of solar/space and meteorological data. Our research suggests that the historic March 2012 heat wave (M2012HW) and the March 1910 heat wave (M1910HW), which occurred a century earlier in NE-USA, were related to Sun-generated special space plasma structures triggering large magnetic storms. Furthermore, the largest (Dst = −222 nT) magnetic storm during solar cycle 24 in March 2015 (only three years later than the March 2012 events) occurred in relation to another heat wave (M2015HW) in NE-USA. Both these heat waves, M2012HW and M2015HW, resemble each other in many ways: they were characterized by extremely huge temperature increases ΔΤΜ = 30° and 32° (with maximum temperatures ΤΜ = 28° and 23°, respectively) during a positive North Atlantic Oscillation index, the high temperatures coincided with large-scale warm air streaming from southern latitudes, they were accompanied by superstorms caused by unexpected geoeffective interplanetary coronal mass ejections (ICMEs), and the ICME-related solar energetic particle (SEP) events were characterized by a proton spectrum extending to very high (>0.5 GeV) energies. We infer that (i) all three heat waves examined (M2012HW, M2015HW, M1910HW) were related with strong magnetic storms triggered by effective solar wind plasma structures, and (b) the heat wave in March 2012 and the related solar activity was not an accidental coincidence; that is, the M2012HW was most probably affected by solar activity. Future case and statistical studies are needed to further check the hypothesis put forward here, which might improve atmospheric models in helping people’s safety, health and life. Full article
(This article belongs to the Special Issue Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) Models (Vol. 2))
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16 pages, 1909 KiB  
Article
Time Behaviour of Helium Atmospheric Pressure Plasma Jet Electrical and Optical Parameters
by Ioana Cristina Gerber, Ilarion Mihaila, Dennis Hein, Andrei Vasile Nastuta, Roxana Jijie, Valentin Pohoata and Ionut Topala
Appl. Sci. 2017, 7(8), 812; https://doi.org/10.3390/app7080812 - 9 Aug 2017
Cited by 16 | Viewed by 6640
Abstract
Low temperature plasma jets gained increased interest in the last years as a potential device in many life science applications, including here human or veterinary medicine. Standardisation of plasma sources and biological protocols are necessary for quality assurance reasons, due to the fact [...] Read more.
Low temperature plasma jets gained increased interest in the last years as a potential device in many life science applications, including here human or veterinary medicine. Standardisation of plasma sources and biological protocols are necessary for quality assurance reasons, due to the fact that this type of atmospheric pressure plasma source is available in multiple configurations and their operational parameters span also on a broad range of items, such as all characteristics of high voltage pulses used for gas breakdown, geometrical characteristics, gas feed composition and conductive or biological target characteristics. In this paper we present results related to electrical, optical and molecular beam mass spectrometry diagnosis of a helium plasma jet, emphasising the influence of various operational parameters of the high voltage pulses on plasma jet properties. Discussion on physical parameters that influence the biological response is included, together with important results on plasma sources statistical behaviour until reaching a quasi-stationary working regime. The warm-up period of the plasma jet, specific to many other plasma sources, must be precisely known and specified whenever the plasma jets are used as a tool for life science applications. Full article
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