sulfur hexafluoride
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2021 ◽  
Vol 9 ◽  
Author(s):  
Beata Gavurova ◽  
Martin Rigelsky ◽  
Viera Ivankova

In the current era of globalization, a clean environment remains a crucial factor for the health of the population. Thus, improving air quality is a major focus of environmental policies, as it affects all aspects of nature, including humans. For these reasons, it is appropriate to take into account the health risks posed by greenhouse gas (GHG) emissions released into the atmosphere. With regard to global GHG emissions, there are concerns about the loss of protection of the ozone layer and it is very likely that climate change can be expected, which multiplies the environmental threat and has potentially serious global consequences. In this regard, it is important to pay increased attention to emissions that enter the atmosphere, which include countless toxic substances. The aim of this study was to examine the associations between selected GHG emissions and the health of the European Union (EU) population represented by disability-adjusted life years (DALYs). This aim was achieved using several analytical procedures (descriptive analysis, correlation analysis, cluster analysis, and panel regression analysis), which included five environmental variables (carbon dioxide (CO2), methane (CH4) in CO2 equivalent, nitrous oxide (N2O) in CO2 equivalent, hydrofluorocarbons (HFC) in CO2 equivalent, sulfur hexafluoride (SF6) in CO2 equivalent) and one health variable (DALYs). An emphasis was placed on the use of quantitative methods. The results showed that CO2 emissions have a dominant position among selected GHG emissions. The revealed positive link between CO2 and DALYs indicated that a decrease in CO2 may be associated with a decrease in DALYs, but it is also true that this cannot be done without reducing emissions of other combustion products. In terms of CO2, the least positive scores were observed in Luxembourg and Estonia. Germany had the lowest score of DALYs, representing the most positive health outcome in the EU. In terms of total GHG emissions, Ireland and Luxembourg were considered to be less positive countries compared to the other analyzed countries. Countries should focus on reducing GHG emissions in general, but from a health point of view, reducing CO2 emissions seems to be the most beneficial.


2021 ◽  
pp. 112067212110589
Author(s):  
Tomaso Caporossi ◽  
Lorenzo Governatori ◽  
Tommaso Verdina ◽  
Stanislao Rizzo

Introduction We described a case of initial unsuccessful outcome of failed macular hole treated with amniotic membrane, that resolved after amniotic membrane exchange and silicone oil injection. Case Description a woman affected by a high myopic macular hole that had failed to close after multiple surgeries, had been treated using an amniotic membrane graft and 20% sulfur hexafluoride but, after the gas reabsorption, the macular hole was still open, and the amniotic membrane. A second surgery with a second amniotic membrane patch and silicone oil was carried out. Two weeks after the procedure the macular hole closed, and the final visual acuity improved from 20/400 to 20/100. Conclusions In this case, a second surgery, using a new amniotic membrane graft and a longer-lasting endotamponade, closed the hole and improved the visual acuity.


2021 ◽  
Vol 2091 (1) ◽  
pp. 012011
Author(s):  
P A Nikitin ◽  
A K Nikitin

Abstract The paper presents results of experimental investigation of an acousto-optic modulator of terahertz radiation based on liquefied sulfur hexafluoride. It was found that the intensity of diffracted radiation at a fixed ultrasound power depends on the dimensions of the ultrasound transducer. The optimal size of the ultrasound transducer in the direction orthogonal to the plane of the acousto-optic interaction was determined, at which the maximum energy efficiency of the acousto-optic modulator was achieved.


2021 ◽  
Vol 16 (5) ◽  
pp. 465
Author(s):  
Noor Mazliza Badrul Sham ◽  
Muhammad Saufi Kamarudin ◽  
Hidayat Zainuddin ◽  
Rahisham Abd-Rahman

2021 ◽  
Vol 14 (10) ◽  
pp. 6795-6819
Author(s):  
Eric J. Hintsa ◽  
Fred L. Moore ◽  
Dale F. Hurst ◽  
Geoff S. Dutton ◽  
Bradley D. Hall ◽  
...  

Abstract. UCATS (the UAS Chromatograph for Atmospheric Trace Species) was designed and built for observations of important atmospheric trace gases from unmanned aircraft systems (UAS) in the upper troposphere and lower stratosphere (UTLS). Initially it measured major chlorofluorocarbons (CFCs) and the stratospheric transport tracers nitrous oxide (N2O) and sulfur hexafluoride (SF6), using gas chromatography with electron capture detection. Compact commercial absorption spectrometers for ozone (O3) and water vapor (H2O) were added to enhance its capabilities on platforms with relatively small payloads. UCATS has since been reconfigured to measure methane (CH4), carbon monoxide (CO), and molecular hydrogen (H2) instead of CFCs and has undergone numerous upgrades to its subsystems. It has served as part of large payloads on stratospheric UAS missions to probe the tropical tropopause region and transport of air into the stratosphere; in piloted aircraft studies of greenhouse gases, transport, and chemistry in the troposphere; and in 2021 is scheduled to return to the study of stratospheric ozone and halogen compounds, one of its original goals. Each deployment brought different challenges, which were largely met or resolved. The design, capabilities, modifications, and some results from UCATS are shown and described here, including changes for future missions.


Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3507
Author(s):  
Zhen Shi ◽  
Sheng-Yuan Xia

The scavenging and detection of sulfur hexafluoride (SF6) decomposition products (SO2, H2S, SO2F2, SOF2) critically matters to the stable and safe operation of gas-insulated switchgear (GIS) equipment. In this paper, the Rh-doped nitrogen vacancy boron nitride monolayer (Rh-VNBN) is proposed as a gas scavenger and sensor for the above products. The computational processes are applied to investigate the configurations, adsorption and sensing processes, and electronic properties in the gas/Rh-VNBN systems based on the first-principle calculations. The binding energy (Eb) of the Rh-VNBN reaches −8.437 eV, while the adsorption energy (Ead) and band gap (BG) indicate that Rh-VNBN exhibits outstanding adsorption and sensing capabilities. The density of state (DOS) analysis further explains the mechanisms of adsorption and sensing, demonstrating the potential use of Rh-VNBN in sensors and scavengers of SF6 decomposition products. This study is meaningful as it explores new gas scavengers and sensors of SF6 decomposition products to allow the operational status assessment of GIS equipment.


2021 ◽  
Vol 21 (19) ◽  
pp. 14927-14940
Author(s):  
Quanfu He ◽  
Zheng Fang ◽  
Ofir Shoshanim ◽  
Steven S. Brown ◽  
Yinon Rudich

Abstract. Accurate Rayleigh scattering and absorption cross sections of atmospheric gases are essential for understanding the propagation of electromagnetic radiation in planetary atmospheres. Accurate extinction cross sections are also essential for calibrating high-finesse optical cavities and differential optical absorption spectroscopy and for accurate remote sensing. In this study, we measured the scattering and absorption cross sections of carbon dioxide, nitrous oxide, sulfur hexafluoride, oxygen, and methane in the continuous wavelength range of 307–725 nm using broadband cavity-enhanced spectroscopy (BBCES). The experimentally derived Rayleigh scattering cross sections for CO2, N2O, SF6, O2, and CH4 agree with refractive index-based calculations, with a difference of (0.4 ± 1.2) %, (−0.6 ± 1.1) %, (0.9 ± 1.4) %, (2.8 ± 1.2) %, and (0.9 ± 2.2) %, respectively. The O2–O2 collision-induced absorption and absorption by methane are obtained with high precision at the 0.8 nm resolution of our BBCES instrument in the 307–725 nm wavelength range. New dispersion relations for N2O, SF6, and CH4 were derived using data in the UV–vis wavelength range. This study provides dispersion relations for refractive indices, n-based Rayleigh scattering cross sections, and absorption cross sections based on more continuous and more extended wavelength ranges than available in the current literature.


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