Reconstruction of large scale flow structures in a stirred tank from limited sensor data

We combine reduced order modelling and system identification to reconstruct the temporal evolution of large scale vortical structures behind the blades of a Rushton impeller. We performed Direct Numerical Simulations at Reynolds number 600 and employed proper orthogonal decomposition (POD) to extract the dominant modes and their temporal coefficients. We then applied the identification algorithm, N4SID, to construct an estimator that captures the relation between the velocity signals at sensor points (input) and the POD coefficients (output). We show that the first pair of modes can be very well reconstructed using the velocity time signal from even a single sensor point. A larger number of points improves accuracy and robustness, and also leads to better reconstruction for the second pair of POD modes. Application of the estimator derived at Re=600 to the flows at Re=500 and 700, shows that it is robust with respect to changes in operating conditions

Activity of the right cardiac ventricle and metabolism in healthy persons during an orthostatic test after short term immobilization

A 15 minute orthostatic test was performed on healthy male volunteers under conditions of catheterization of the right ventricle of the heart and the radial (or brachial) artery before and after 5 day bedrest in an antiorthostatic position of the body (with the foot of the bed raised 4.5 degrees). The change to a vertical position after immobilization was attended by a more marked increase in the rate of cardiac contractions, an increase of max dp/dt pressure in the right ventricle, and a decrease of cardiac and stroke indices. The decrease of the cardiac index was compensated for, to a certain measure, by a further increase in the extraction and utilization of O2 by the tissues. The arterial blood pH did not change essentially, while the decrease in pCO2 and content of standard bicarbonate was more marked

Carbon Sequestration Dynamics in Urban-Adjacent Forests: A 50-Year Analysis

Achieving carbon neutrality is crucial for urban ecosystems. Forests growing near cities largely determine the state of the environment in urban areas. The aim of the present research is to assess the carbon productivity dynamics in forests near Krasnoyarsk (a large industrial center) over a 50-year period in terms of carbon sequestration and conservation. The study was based on forest inventory conducted in Karaul'noe Forestry in 1972, 1982, and 2002 and forest inventory covering six forest compartments in 2022. The forest covers 3980 ha and consists of 52 forest compartments. The analysis was based on the assessment of carbon productivity dynamics and followed four levels of principles: forestry, structure, forest compartment, and forest stand. The research was based on forest fund dynamics, analyzing methods, long-term forest inventory, assessing carbon stock, and growing stock dynamics. Pine is the dominant forest-forming species that absorbs the most carbon in the study area. Pine is long-lived, covers a vast area, and has the highest carbon sequestration potential. At the forest structure level, the predominant carbon pools are mid-late successional and late successional stands dominated by pine, birch, and aspen. Forest compartment-level analysis revealed three trends in carbon sequestration: carbon balance, a decrease in carbon sequestration, and an increase in carbon sequestration. Notably, the prevailing trend is determined by changes in carbon sequestration by dominant forest-forming species (pine). Forest stand-level analysis showed that stands have become more and more uneven-aged. About 65% of total carbon stock is concentrated in mid successional, mid-late successional and late-successional stands, and 35% in young stands. The carbon sequestration rate decreases in forests with age. However, pine forests increase biological productivity and continue to successfully sequester carbon. Deciduous forests have lost their carbon sequestration potential, and the area they occupy is currently decreasing in the study area. The development of the young generation in pine stands suggests that the carbon sequestration potential in forests growing near the city will not decrease and may even increase due to climate change. Doi: 10.28991/CEJ-2023-09-09-08 Full Text: PD

ANKLE JOINT REPLACEMENT (REVIEW)

Ankle joint replacement remains the most promising but at the same time one of the most challenging fields of orthopedics. In this article the authors analyzed the history of ankle joint replacement development with meticulous details of the prosthesis structure as well as complications occurring with different generations of the prosthesis. Major tendencies of development and improvements of the prosthesis are described while taking into account the complicated biomechanics of the ankle joint. Based on the completed analysis the conclusion was made that using new materials in combination with improved structure allows for major improvements in the ankle joint replacement

РОЛЬ ЭПИКАРДИАЛЬНОГО КАРТИРОВАНИЯ И АБЛАЦИИ В ЛЕЧЕНИИ ЖЕЛУДОЧКОВЫХ ТАХИКАРДИЙ

Ventricular tachyarrhythmias are among the main problems in cardiology and electrophysiology. Drugs treatment is often ineffective in patients with ventricular tachycardia (VT), while interventional approach is more successful. Nevertheless, despite the progress in visualization and catheter ablation technologies, there is still significant ventricular tachycardia recurrence rate over time. There is a number of reports showing that the main cause of endocardial ablation failure is deep intramural and subepicardial location of arrhythmogenic foci.An elegant percutaneous technique using a subxyphoid access has been proposed in order to reach the pericardial space. Combination of endoand epicardial mapping and ablation has revolutionized ventricular tachycardia management in patients with structural heart diseases, allowing much better success in specific patient population. This review summarizes current achievements in epicardial mapping and ablation in complex ventricular tachycardia management.Желудочковые нарушения ритма являются одной из главных проблем в современной кардиологии, аритмологии. Медикаментозный подход к лечению желудочковых аритмий часто неэффективен, в то время как интервенционный подход позволяет достигнуть определённых успехов в лечении желудочковых тахикардий (ЖТ). Тем не менее, несмотря на достигнутые успехи в данной области, не у всех пациентов удаётся достигнуть отсутствия рецидивов ЖТ. В результате многочисленных наблюдений было доказано, что причиной неэффективного радиочастотного воздействия на субстрат ЖТ с эндокардиальной поверхности может являться субэпикардиальное/интрамуральное расположение аритмогенного очага. В связи с этим был предложен метод эпикардиального доступа с после дующими картированием и аблацией аритмогенного субстрата.В настоящее время многие исследователи занимаются проблемой оценки отдаленных результатов эпикардиального подхода, выявлением предикторов рецидивов ЖТ, совершенствованием методик картирования и профилактикой осложнений

Review of AdS/CFT Integrability, Chapter II.2: Quantum Strings in AdS5xS5

We review the semiclassical analysis of strings in AdS5xS5 with a focus on the relationship to the underlying integrable structures. We discuss the perturbative calculation of energies for strings with large charges, using the folded string spinning in an AdS3 subset of AdS5 as our main example. Furthermore, we review the perturbative light-cone quantization of the string theory and the calculation of the worldsheet S-matrix.Comment: 20 pages, see also overview article arXiv:1012.3982, v2: references to other chapters update

Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal