On Lamb wave propagation from small surface explosions in the atmospheric boundary layer

The problem of Lamb waves propagation from small explosions in the atmospheric boundary layer are discussed. The results of lamb waves registrations from surface explosions with yields varied from 3 tons up to a few hundred tons (TNT equivalent) are presented. The source-receiver distances varied from 20 km up to 310 km. Most of the explosions were conducted during the evening and early morning hours when strong near-surface temperature and wind inversions existed. The corresponding profiles of effective sound velocity are presented. Some of the explosions had been realized with 15 minute intervals between them when morning inversion being destroyed. Corresponding transformation of Lamb waves was observed. The Korteveg-de Vrize equation to explain experimental data on Lamb waves propagation along earth surface is used

РАСПРОСТРАНЕННОСТЬ КАРДИАЛЬНЫХ ФАКТОРОВ РИСКА У ПАЦИЕНТОВ С АНЕВРИЗМОЙ БРЮШНОЙ АОРТЫ

Introduction. According to the literature, 27 to 65 % of patients with abdominal aortic aneurysm also suffer from coronary heart disease. Mortality from coronary heart disease after surgical treatment for abdominal aortic aneurysm according to some data exceeds 20 %.Objective: improvement of results of treatment of patients with combined lesions of coronary arteries and aneurysm of the abdominal aortaSubjects and method. A retrospective analysis of case histories of 100 patients hospitalized in our clinic diagnosed with «abdominal aortic aneurysm» for examination. Of all patients, 37 % were diagnosed with significant coronary artery lesions. The average ejection fraction was 58.2 ± 5.4 %, 13 % of the study diagnosed significant violations of local myocardial contractility. 16 % of patients had previous myocardial infarction, 7 % – a permanent form of atrial fibrillation. 4 % of patients complained of chest pain during exercise. Hypertension was present in 100 % of patients, the average maximum systolic blood pressure was 176 ± 24.5 mmHg.Results. Hospital mortality was 2 % (all patients were non-operated on coronary arteries and had no significant coronary pathology). There were no significant complications (cardiac, neurological, respiratory) in the early postoperative period. The average length of hospital stay was 9.8 ± 1.99 bed days.Conclusions. Determination of cardiac status before surgery for abdominal aortic aneurysm is the most important moment of stratification of the risk of perioperative complications. Coronary angiography in patients with abdominal aortic aneurysm is a mandatory point of diagnosis, allowing to identify cardiac risk factors.Введение. Согласно данным литературы, от 27 до 65 % пациентов с аневризмой брюшной аорты также страдают ишемической болезнью сердца (ИБС). Смертность от ИБС после оперативного лечения по поводу аневризмы брюшной аорты, по некоторым данным, превышает 20 %.Цель: улучшение результатов лечения пациентов с сочетанным поражением коронарных артерий и аневризмой брюшной аорты.Материал и методы. Проведен ретроспективный анализ историй болезни 100 пациентов, госпитализированных в ОАП НМИЦССХ им. А. Н. Бакулева с диагнозом «аневризма брюшной аорты» для обследования. Из всех пациентов у 37 % диагностированы значимые поражения коронарных артерий. Средний показатель фракции выброса составил 58,2 ± 5,4 %, у 13 % по данным исследования диагностированы значимые нарушения локальной сократимости миокарда. 16 % пациентов ранее перенесли инфаркт миокарда, у 7 % отмечена постоянная форма фибрилляции предсердий. 4 % пациентов предъявляли жалобы на загрудинные боли при физической нагрузке. Артериальная гипертензия присутствовала у 100 % пациентов, средний показатель максимального систолического артериального давления составил 176 ± 24,5 мм рт. ст.Результаты. Госпитальная летальность составила 2 % (все пациенты, не имеющие значимой коронарной патологии, ранее не оперированы на коронарных артериях). Значимых осложнений (кардиальных, неврологических, респираторных) в раннем послеоперационном периоде не отмечалось. Средняя длительность пребывания в стационаре составила 9,8 ± 1,99 койко-дня.Выводы. Определение кардиального статуса перед оперативным вмешательством по поводу аневризмы брюшной аорты – важнейший момент стратификации риска развития периоперационных осложнений. Выполнение коронарографии у пациентов с аневризмой брюшного отдела аорты является обязательным пунктом диагностики, позволяющим выявить кардиальные факторы риска

Toward an improved representation of middle atmospheric dynamics thanks to the ARISE project

This paper reviews recent progress toward understanding the dynamics of the middle atmosphere in the framework of the Atmospheric Dynamics Research InfraStructure in Europe (ARISE) initiative. The middle atmosphere, integrating the stratosphere and mesosphere, is a crucial region which influences tropospheric weather and climate. Enhancing the understanding of middle atmosphere dynamics requires improved measurement of the propagation and breaking of planetary and gravity waves originating in the lowest levels of the atmosphere. Inter-comparison studies have shown large discrepancies between observations and models, especially during unresolved disturbances such as sudden stratospheric warmings for which model accuracy is poorer due to a lack of observational constraints. Correctly predicting the variability of the middle atmosphere can lead to improvements in tropospheric weather forecasts on timescales of weeks to season. The ARISE project integrates different station networks providing observations from ground to the lower thermosphere, including the infrasound system developed for the Comprehensive Nuclear-Test-Ban Treaty verification, the Lidar Network for the Detection of Atmospheric Composition Change, complementary meteor radars, wind radiometers, ionospheric sounders and satellites. This paper presents several examples which show how multi-instrument observations can provide a better description of the vertical dynamics structure of the middle atmosphere, especially during large disturbances such as gravity waves activity and stratospheric warming events. The paper then demonstrates the interest of ARISE data in data assimilation for weather forecasting and re-analyzes the determination of dynamics evolution with climate change and the monitoring of atmospheric extreme events which have an atmospheric signature, such as thunderstorms or volcanic eruptions

Infrasonic interferometry of stratospherically refracted microbaroms: A numerical study

The atmospheric wind and temperature can be estimated through the traveltimes of infrasound between pairs of receivers. The traveltimes can be obtained by infrasonic interferometry. In this study, the theory of infrasonic interferometry is verified and applied to modeled stratospherically refracted waves. Synthetic barograms are generated using a raytracing model and taking into account atmospheric attenuation, geometrical spreading, and phase shifts due to caustics. Two types of source wavelets are implemented for the experiments: blast waves and microbaroms. In both numerical experiments, the traveltimes between the receivers are accurately retrieved by applying interferometry to the synthetic barograms. It is shown that microbaroms can be used in practice to obtain the traveltimes of infrasound through the stratosphere, which forms the basis for retrieving the wind and temperature profiles.Control & OperationsAerospace Engineerin