Globalization and Trade in the Post-Covid World

The COVID-19 pandemic brought an extraordinary disturbance regarding the worldwide economy and global trade, as creation and utilization downsized. Perhaps the best methodology for addressing this type of emergency is convenient, unspoiled information. An informed public is better established to use wise judgment including on cases recognized for trade. This is the situation, and a devoted page at WTO site has been created. This will provide present data related with trade information. The chapter discusses rising protectionism in course of the last half period, unexpected monetary crises created by the pandemic, disturbances regarding production network movement, and shocks related to market interest. Reporters worldwide have trumpeted the 'finish' of globalization.

Choosing an approach to statistical processing of the ship’s pitching record

The developed instrumentation and software provides discrete values for the angles of a vessel’s list on an operational voyage in sea conditions at specified time intervals.The half-periods of pitching are considered; the half-period and the corresponding pitching amplitude can be obtained in three different ways: as the amplitude from one board to the other one with the reference of the initial peak-to-peak amplitude or with the reference of the final peak-to-peak amplitude; as the time interval of the ship listing on one side between zero roll angles. It was found that each method corresponds to its own, different from the others, amplitude-period statistics. This makes it difficult to compare different registrations and identify the essential reactions of the vessel to the seaway, unless a method is specified for determining the half-periods and linking the roll amplitudes to them. The proposal is justified to unify the processing by defining the half-period as the time of the ship listing on one board with the corresponding amplitude angle of the roll, that is, as the difference of the moments of time between two next values of the zero angle of the roll.

Recording of the ship’s motion in operation on irregular waves and its processing

The safety of the ship state during the voyage is ensured, among other things, by monitoring the state of the ship’s stability. A device for measuring the parameters of the ship’s motion and software for discrete motion recording into a computer have been developed in Siberian State University of Water Transport. With the use of the device, a full-scale experiment to record the motion of the motor ship “Grumant” during an operational voyage has been carried out. For this, the half-periods of rolling and their amplitudes are obtained. Amplitude-half-period distribution of rolling has been built. According to the maximum probability, the half-period of its own roll has been found from it, which makes it possible to assess the stability state of the vessel during the voyage. The spectrum of motion and rolling dispersion has been obtained. If it is possible to obtain objective information about the actual wave spectrum, this opens the way to obtaining the amplitude-frequency characteristic of the motion based on the Wiener- Khinchin theorem. This task is set as a priority for the development of research in this area with the prospect of optimizing vessel navigation in difficult hydrometeorological conditions.

Exact Universal Excitation Waveform for Optimal Enhancement of Directed Ratchet Transport

We show the existence and properties of an exact universal excitation waveform for optimal enhancement of directed ratchet transport (in the sense of the average velocity) by providing three alternative derivations. Specifically, it is deduced from the criticality scenario giving rise to ratchet universality as well as from an approach based on Fokker–Planck’s equation. Numerical experiments confirmed the existence of such exact universal excitation waveform in the context of a driven overdamped Brownian particle subjected to a periodic potential. While the universality scenario holds regardless of the waveform of the periodic vibratory excitations involved, it is shown that the enhancement of directed ratchet transport is optimal when the impulse transmitted by those excitations (time integral over a half-period) is maximum.

Long-Lasting Event-Related Beta Synchronizations of Electroencephalographic Activity in Response to Support-Surface Perturbations During Upright Stance: A Pilot Study Associating Beta Rebound and Active Monitoring in the Intermittent Postural Control

Movement related beta band cortical oscillations, including beta rebound after execution and/or suppression of movement, have drawn attention in upper extremity motor control literature. However, fewer studies focused on beta band oscillations during postural control in upright stance. In this preliminary study, we examined beta rebound and other components of electroencephalogram (EEG) activity during perturbed upright stance to investigate supraspinal contributions to postural stabilization. Particularly, we aimed to clarify the timing and duration of beta rebound within a non-sustained, but long-lasting postural recovery process that occurs more slowly compared to upper extremities. To this end, EEG signals were acquired from nine healthy young adults in response to a brief support-surface perturbation, together with the center of pressure, the center of mass and electromyogram (EMG) activities of ankle muscles. Event-related potentials (ERPs) and event-related spectral perturbations were computed from EEG data using the perturbation-onset as a triggering event. After short-latency (<0.3 s) ERPs, our results showed a decrease in high-beta band oscillations (event-related desynchronization), which was followed by a significant increase (event-related synchronization) in the same band, as well as a decrease in theta band oscillations. Unlike during upper extremity motor tasks, the beta rebound in this case was initiated before the postural recovery was completed, and sustained for as long as 3 s with small EMG responses for the first half period, followed by no excessive EMG activities for the second half period. We speculate that those novel characteristics of beta rebound might be caused by slow postural dynamics along a stable manifold of the unstable saddle-type upright equilibrium of the postural control system without active feedback control, but with active monitoring of the postural state, in the framework of the intermittent control.

Methods for determining focal mechanisms in laboratory experiments

<p>In laboratory experiments, acoustic emission (AE) caused by the deformation of geomaterial reflects changes in the strength and stress state of the sample. By analogy with the solution of focal mechanisms of earthquake sources, there are several methods for determining the mechanisms and types of AE sources using the amplitudes and signs of the first arrival of an elastic wave on sensors that register acoustic signals. With 16 receiving acoustic sensors, the number of polarity determinations of the incoming wave usually does not exceed 5-10, while the sign determination on some sensors is often incorrect due to the omission of the first half-period of the weak signal by the automatic registration algorithm. This reduces the reliability of determining the mechanism of the focus in laboratory tests of rocks by wellknown methods based on the distribution of signs of the first arrival of the AE wave. We propose a method for determining the directions of the axes and the values of compression and tension in the AE source. The algorithm uses information about the coordinates of events and receivers, values of amplitudes and signs of the first half-period of P-waves coming to the receivers. In this case, the model of the AE source is assumed as a quadrupole with compression and tension axes. The source-receiver distance, the directional diagram of the receiver, and the emission diagram of the source are taken into account for each of the receivers to calculate the value of displacements in the source. To test the proposed algorithm and compare it with the known methods, there was developed a program for generating an acoustic signal source of a given type with random coordinates and directions of the compression and tension axes. An array of signs and amplitudes of the first arrivals coming to the receivers was calculated from simulated data. The high efficiency of the proposed algorithm was shown. The usage of this method together with the determination of AE event types [Zang et.al., 1998] in real laboratory experiments allows us to characterize the prevailing processes of destruction during separate phases of the experiment on triaxial loading of rocks in more detail. The developed algorithm makes it possible to determine the directions of the axes and the values of compression-tension with a minimum number of signs of the arrivals of P- waves, to estimate the components of the seismic moment tensor and obtain more complete information about the mechanism of the AE source.</p><p>The work was supported partly by the mega-grant program of the Russian Federation Ministry of Science and Education under the project no. 14.W03.31.0033 and partly by the state assignment of the Ministry to IPE RAS.</p>

Features of excitation of a linear electromechanical converter of induction type from an AC source

Purpose. The purpose of the article is to establish the basic laws of operation of induction-type linear electromechanical converter (LEMС) during operation in high-speed and shock-power modes and excitation from an AC source of increased frequency. Methodology. With the help of a mathematical model, the regularities of the course of processes in a LEMС, excited from an AC source, were established when working with shock-power and high-speed modes. The solutions of the equations of the mathematical model, which describe interrelated electrical, magnetic, mechanical and thermal processes, are presented in a recurrent form. Results. It was found that when the LEMC operates in the shock-power mode, the maximum value of the current in the inductor winding occurs in the first half-period, and in the inhibited armature winding in the second half-period. The electrodynamic force changes at twice the frequency, taking on both positive and negative values. Since the positive values exceed the negative ones, the magnitude of the impulse of the electrodynamic force increases with each period of the force. Depending on the initial voltage phase, the relative change in the magnitude of the force impulse is 1.5 %. It was found that when the LEMC operates in high-speed mode, the current in the inductor winding in the first half-period has the greatest value, but after several periods it takes on a steady state. The temperature rise of the inductor winding increases with the time of connection to the AC source, and the temperature rise of the armature winding has the nature of saturation. The electrodynamic force has an oscillatory character with strong damping and a significant predominance of the positive component. Depending on the initial phase of the voltage, the relative change in the maximum speed of the armature winding is 2.5 %. Originality. For the first time, a mathematical model of the LEMC, excited from an AC source, was developed, the solutions of the equations of which describe the interrelated electrical, magnetic, mechanical and thermal processes. For the first time, the regularities of the course of processes in LEMC were established when working with shock-power and high-speed modes. Practical value. The characteristics of LEMC are obtained, which determine the efficiency of work in shock-power and high-speed modes. It is shown that the initial voltage phase has no significant effect on the power, high-speed thermal performance of the converter excited from an alternating current source.