Dominic J. O’Meara, Cosmology and Politics in Plato’s Later Works, Cambridge University Press, 2017, xi + 157 pp., https://doi.org/10.1017/9781316869581

Reid, Jeremy

doi:10.1515/agph-2019-2008

Cited by 3 publications

(3 citation statements)

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“…The width of the IEDF generally indicates the relative length of the ionization region overlapped with the acceleration region [41]. Therefore, an increased width of the IEDF as seen in figure 5(b) probably suggests an extension of the ionization region along the Ar fractions unless the acceleration region changes significantly.…”

Section: Discussionmentioning

confidence: 95%

Argon admixture-driven enhanced ionization and performance of a 5 kW Hall thruster on krypton

Lee,

Brabston,

Lev

et al. 2024

J. Phys. D: Appl. Phys.

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Utilizing alternative propellants has been recognized as a strategy to reduce the total cost of propellants in electric propulsion-based missions. The aim of this study is to quantify the Hall effect thruster (HET) performance and operating characteristics using a Kr-Ar mixture to enable mission designers to evaluate the impact on mission and spacecraft design. We present the performance and plume plasma properties of the P5 5 kW-class HET operated with a Kr-Ar mixture with Ar volumetric flow rate fractions from 0 to 100%. The thruster is characterized at discharge power levels of 2.6 kW and 4.1 kW at constant discharge current and voltage over the range of Ar fractions. Despite higher ionization energy and lower mass of Ar, the thruster exhibited a similar level of thrust within 2% when comparing the pure Kr and 26%-Ar mixture cases. The derived ion energy distribution functions and analytical modeling suggest that the characteristic length for the ionization region is extended as the Ar fraction increases. The increased residence time of Kr at the extended ionization region and background energetic electrons from the ionized Ar neutrals are considered to cause this enhanced ionization of the injected Kr neutrals, leading to a 6% higher Kr ion density at the 26%-Ar case even at the 16% reduced injected neutral density than in the pure Kr case. The enhanced Kr ionization and generated Ar ions in the 26%-Ar case consequently led to a comparable thrust with that of the pure Kr case. The study indicates that mixing Ar with approximately 26% volumetrically with Kr can provide a similar or even higher thrust performance at the same discharge power. This will be particularly advantageous for various space missions that require high impulses by reducing the total cost of the propellant.

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Section: Discussionmentioning

confidence: 95%

Argon admixture-driven enhanced ionization and performance of a 5 kW Hall thruster on krypton

Lee,

Brabston,

Lev

et al. 2024

J. Phys. D: Appl. Phys.

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“…For instance, MW reactors operating under subsonic flow conditions achieved records of 80% energy efficiency and 25% CO 2 conversion. [ 42 ] Furthermore, under supersonic flow conditions, MW reactors achieved even higher energy efficiency of 90%. [ 43 ] Bongers et al [ 9 ] reported a maximum energy efficiency of 47% with a CO 2 conversion rate of 10% at a pressure of 200 mbar.…”

Section: Resultsmentioning

confidence: 99%

Influence of humidity on the plasma‐assisted CO₂ conversion

Attri,

Okumura,

Takeuchi

et al. 2023

Plasma Processes & Polymers

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The current research focuses on carbon dioxide (CO2) conversion at ambient conditions using streamer plasma. In this study, treatment time and humidity have been found to influence CO2 conversion. Our findings reveal a maximum CO2 conversion rate of 35.2%, achieved with a remarkably high energy efficiency of CO2 conversion at 135% and a low energy cost of 2.17 eV/molecule. We employed optical emission and fourier‐transform infrared spectroscopy spectroscopy to analyze the different dissociation products of CO2 and determine the percentage of CO2 conversion. Furthermore, we utilized a two‐dimensional (2D) fluid dynamics model and a zero‐dimensional (0D) chemistry model to gain insights into the reactor mechanism.

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confidence: 99%

Cognitively testing Aotearoa’s food security questionnaire in the modern context

Follong,

Haliburton,

Mackay

et al. 2024

Proc. Nutr. Soc.

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The eight well-known food security indicators were developed in 1997 using a stepwise process that involved five focus group interviews (one Māori, one Pakeha, two Pacific, and one mixed ethnicity) of 8-16 people, all of whom were either on a low income or were government beneficiaries(1). As part of the development of the tools and methods for a future New Zealand National Nutrition Survey, these eight indicators were considered for inclusion. The Māori and Technical Advisory Groups convened for the development of the National Nutrition Survey foresaw issues with the interpretation of some of the questions given the changes in the food environment and sources of food assistance in the last 25 years and recommended that cognitive testing should be conducted to see if changes were required. Participants were recruited through two community organisations, a local marae, and community Facebook pages. Participants were given the option of participating in a one-on-one interview or as part of a focus group. During each session, participants were asked five (three original and two new) questions relating to food security (running out of basics, use of food assistance, household food preparation and storage resources). After each question, the participants were asked a series of additional probing questions to ascertain whether they had interpreted the question as intended. All interviews were audio recorded and transcribed, and a qualitative analysis was performed on the transcripts to determine areas of concern with each question. A total of 46 participants completed the cognitive testing of the food security questions, including 26 aged 18-64 years, and 20 aged 65+ years. Participants also spanned a range of ethnicities including 8 Māori, 15 Pasifika, 15 Asian, and 8 New Zealand European or Other. Just over half of the participants (n=24) reported themselves to be financially secure, 16 participants reported that their financial security was borderline, 1 participant reported that they were not at all financially secure, and 5 participants declined to answer. Variable interpretations of terms by participants were found in all questions that were tested. Therefore, answers to the food security questions may have not reflected the actual experience of participants. This study also identified other dimensions of food security not assessed by the current eight indicators (e.g., lack of time, poor accessibility). These findings indicate that the food security questions need to be improved to ensure they are interpreted as intended and that new questions are needed that considers all dimensions of food insecurity (i.e., access, availability, utilisation, and stability). These new and amended questions should be cognitively tested in groups that are more likely to be experiencing food insecurity.

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Dominic J. O’Meara, Cosmology and Politics in Plato’s Later Works, Cambridge University Press, 2017, xi + 157 pp., https://doi.org/10.1017/9781316869581

Cited by 3 publications

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Argon admixture-driven enhanced ionization and performance of a 5 kW Hall thruster on krypton

Argon admixture-driven enhanced ionization and performance of a 5 kW Hall thruster on krypton

Influence of humidity on the plasma‐assisted CO₂ conversion

Cognitively testing Aotearoa’s food security questionnaire in the modern context

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Dominic J. O’Meara, Cosmology and Politics in Plato’s Later Works, Cambridge University Press, 2017, xi + 157 pp., https://doi.org/10.1017/9781316869581

Cited by 3 publications

References 0 publications

Argon admixture-driven enhanced ionization and performance of a 5 kW Hall thruster on krypton

Argon admixture-driven enhanced ionization and performance of a 5 kW Hall thruster on krypton

Influence of humidity on the plasma‐assisted CO2 conversion

Cognitively testing Aotearoa’s food security questionnaire in the modern context

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Influence of humidity on the plasma‐assisted CO₂ conversion