Comparative analysis of the performance of selective and group repeat transmission modes in a transport protocol

We propose a model of a virtual connection controlled by a transport protocol in the selective and group failure modes as a Markov chain with discrete time that accounts for the influence of protocol parameters of window size and timeout duration for waiting for acknowledgements, probabilities of distorting segments in individual links of the data transmission path on the throughput of a transport connection. We have analyzed how the throughput of the control procedure depends on protocol parameters, level of errors in communication channels, and round-trip delay. We have proposed a method for choosing protocol parameters

Key principle of the efficient running, swimming, and flying

Empirical observations indicate striking similarities among locomotion in terrestrial animals, birds, and fish, but unifying physical grounds are lacking. When applied to efficient locomotion, the analytical mechanics principle of minimum action yields two patterns of mechanical similarity via two explicit spatiotemporal coherent states. In steady locomotory modes, the slow muscles determining maximal optimum speeds maintain universal intrinsic muscular pressure. Otherwise, maximal speeds are due to constant mass-dependent stiffness of fast muscles generating a uniform force field, exceeding gravitation. Being coherent in displacements, velocities and forces, the body appendages of animals are tuned to natural propagation frequency through the state-dependent elastic muscle moduli. Key words: variational principle of minimum action (04.20.Fy), locomotion (87.19.ru), biomechanics (87.85.G-).Comment: Submitted to the Europhysical Letter

Experimental research of neutron yield and spectrum from deuterium gas-puff z-pinch on the GIT-12 generator at current above 2 MA

The Z-pinch experiments with deuterium gas-puff surrounded by an outer plasma shell were carried out on the GIT-12 generator (Tomsk, Russia) at currents of 2 MA. The plasma shell consisting of hydrogen and carbon ions was formed by 48 plasma guns. The deuterium gas-puff was created by a fast electromagnetic valve. This configuration provides an efficient mode of the neutron production in DD reaction, and the neutron yield reaches a value above 1012 neutrons per shot. Neutron diagnostics included scintillation TOF detectors for determination of the neutron energy spectrum, bubble detectors BD-PND, a silver activation detector, and several activation samples for determination of the neutron yield analysed by a Sodium Iodide (NaI) and a high-purity Germanium (HPGe) detectors. Using this neutron diagnostic complex, we measured the total neutron yield and amount of high-energy neutrons

Comparative analysis of the performance of selective and group repeat transmission modes in a transport protocol

We propose a model of a virtual connection controlled by a transport protocol in the selective and group failure modes as a Markov chain with discrete time that accounts for the influence of protocol parameters of window size and timeout duration for waiting for acknowledgements, probabilities of distorting segments in individual links of the data transmission path on the throughput of a transport connection. We have analyzed how the throughput of the control procedure depends on protocol parameters, level of errors in communication channels, and round-trip delay. We have proposed a method for choosing protocol parameters

Академик РАМН Е.Н. Мешалкин (1916–1997) и его мировой приоритет в выполнении успешного кавопульмонального анастомоза в клинике

Идея операции кавопульмонального анастомоза возникла одновременно у хирургов США (А. Блелок), Италии (К. Карлон), СССР (А.Н. Бакулев) и Венгрии (Ф. Робичек). Первый кавопульмональный анастомоз в нескольких модификациях в эксперименте выполнил К. Карлон в конце 1949 г. – начале 1950 г. Первые две неудачные операции в клинике выполнил американский хирург Х. Шумахер до ноября 1954 г. Мировой приоритет в серии успешных операций в клинике принадлежит Е.Н. Мешалкину (с 3 апреля по октябрь 1956 г.). В известном смысле его успех обусловлен экспериментальными исследованиями, выполненными осенью 1955 г. – весной 1956 г. Н.К. Галанкиным, Т.М. Дарбиняном и Д.А. Донецким. Однако вплоть до августа 1956 г. Н.К. Галанкин и его коллеги объективно не были готовы внедрить кавопульмональный анастомоз в клинику. Первый успешный кавопульмональный анастомоз в США 25 февраля 1958 г. выполнил В. Гленн. Опыт автора, его авторитет и публикация в престижном журнале привели к тому, что кавопульмональный анастомоз в литературе называют операцией Гленна (Glenn procedure). Считаем, однако, что правильнее его называть операцией Бакулева – Мешалкина или просто русским анастомозом.Поступила в редакцию 17 июля 2017 г. Принята к печати 13 августа 2017 г.ФинансированиеИсследование не имело спонсорской поддержки.Конфликт интересовАвторы заявляют об отсутствии конфликта интересов.Дополнительная информацияПолный англоязычный текст статьи и список литературы на латинице доступны в электронной версии на сайте журнала: http://journalmeshalkin.ru/index.php/heartjournal/article/view/493</p

Design criteria and validation of a vacuum load current multiplier on a mega-ampere microsecond inductive storage generator

International audienceThe load current multiplier concept (LCM) was suggested for improving the energy transfer efficiency from pulse power generators to loads. The concept was initially demonstrated at atmospheric pressure and dielectric insulation on a compact, 100 kA, microsecond capacitor bank. This paper reports on the LCM design criteria for mega-ampere vacuum pulse power when the LCM comprises a large-inductance magnetic flux extruder cavity without a magnetic core. The analytical and numerical design approach presented was experimentally validated on GIT12 mega-ampere inductive energy storage generator with a constant-inductance load. The LCM technique increased the peak load current from typically 4.6 MA at 1.87 µs on this generator, to 6.43 MA at 2.0 µs. The electromagnetic power into a ~10 nH load increased from 100 GW to 230 GW. This result is in good agreement with the presented numerical simulations and it corresponds to a 95% increase of the achievable magnetic pressure at 8 cm radius in the load. The compact, LCM hardware allows the GIT12 generator to operate more efficiently without modifying the stored energy or architecture. The demonstrated load power and energy increase using the LCM concept is of importance for further studies on power amplification in vacuum and high energy density physics