Search Results (4)

Uncontrolled space debris reentries pose a significant challenge to air traffic management (ATM), often requiring widespread airspace closures to mitigate the perceived risks to aviation safety. In a previous study, we established the probability of collision during such events to be in the order of 10⁻⁷ and classified the event as “extremely remote” but requiring mitigation action. Analyzing the temporal dynamics, we concluded that any given location remains at risk for no more than one minute. Building on these findings, this paper will investigate advanced mitigation strategies to reduce the operational impact of such reentries. We propose utilizing dynamic airspace allocation techniques, using information derived by enhanced reentry prediction models and real-time tracking. Transforming the spatial problem of airspace closures into a temporal one, the study demonstrates the feasibility of confining closures to dynamically moving zones with minimal disruption. A simulation for the Long March 5B reentry case study illustrates the potential for such measures to improve efficiency while maintaining safety standards. Full article

The planned closure of potash mines achieved through the injection of highly mineralized brines into the worked-out area is a complex process. A critical concern arises when brines obstruct the aerodynamic connections between the flooded mine’s airspace and the atmosphere, potentially leading to the formation of closed cavities where explosive gases can accumulate. To address this hazard, it is imperative to develop systems capable of extracting the gas–air mixture from the unflooded part of the worked-out area. Two distinct scenarios are examined: the first involves controlled flooding with saturated brines, while the second contemplates flooding resulting from a hypothetical breakthrough of supra-salt strata, leading to the ingress of groundwater into the worked-out area. A novel mathematical model is introduced to predict the evolution of gas–air mixture parameters in the unflooded part of the worked-out area. Utilizing this model, we assess the effectiveness of proposed measures designed to eliminate explosive gases from the worked-out area. Specifically, a pipeline system is proposed for the removal of gases. The findings from this study contribute valuable insights into ensuring the safe and efficient closure of potash mines, shedding light on potential risks and effective mitigation strategies for gas-related hazards during planned flooding. Full article

COVID-19 has doubtless generated a great negative impact in the tourism industry. The measures disposed by governments to contain the virus included strict lockdowns and the closure of borders and airspaces, without mentioning the imposition of social distancing. As a result of this, thousands of tourists were stranded abroad, without food or financial assistance. The recovery of the industry is slow, and gradually Europe and the US have returned to a new normal. In Argentina, rather, things have become worse. At the end of June, President Fernandez disposed a new border closure that left thousands of Argentineans stranded again. This case report focuses on the testimonies, fears and expectancies of those stranded tourists. Full article

Instroduction: Obstructive sleep apnea is a common disorder, characterized by recurrent narrowing and closure of the upper airway accompanied by intermittent oxyhemoglobin desaturation and sympathetic activation. Ultrasound imaging of the airways has advantages of being safe, quick, repeatable, portable and widely available. Airway ultrasound can visualize and assess the mouth and tongue, oropharynx, hypopharynx, epiglottis, larynx, vocal cords, cricothyroid membrane, cricoid cartilage, trachea, and cervical esophagus. Material and methods: This study assessed the role of ultrasonography in detecting the level and degree of obstruction of airway passages in patients with obstructive sleep apnea (OSA) and its relation to OSA severity. It included thirty-three patients diagnosed as OSA, and ten healthy subjects as a control group. All participants were ≥ 18 years and were subjected to full medical history, Epworth sleepiness score (ESS), thorough clinical examination, complete overnight polysomnography and neck ultrasonography. Results: Ultrasonography findings showed a statistically significant increase in lateral parapharyngeal wall thickness (LPWT) (P < 0.001) and a significant increase in distance between lingual arteries (DLA) (P < 0.01) among OSA patients. Moreover, there was a significant statistical decrease in the retropalatal pharynx transverse diameter (RPD) (P < 0.05) in the OSA group compared to those without OSA. LPWT and DLA are parameters that can be used to predict the severity of OSA. Combination of LPWT and RPD can achieve a 100% sensitivity and specificity. Conclusions: Ultrasound is more objective and convenient than the questionnaire because it doesn’t require overnight time consumption. It is also more relevant than pulse oximetry for examining pharyngeal airspace. Also, this study demonstrated that submental ultrasonography is sufficiently sensitive for differentiating OSA severity. Full article