Laser double optical resonance excitation-ionization of Mo with optogalvanic detection

We report on measurements of resonant three-step, two-colour ionization of atomic molybdenum, using a hollow cathode lamp (HCL) with optogalvanic detection. Wavelength scans were made for two specific transitions involved in the ionization pathways under investigation, namely 4d5(6S)5s 7S3 - 4d5(6S)5p 7P4 and 4d5(6S)5p 7P4 - 4d5(6S)6d 7D5.So-called ‘slow’ and ‘fast’ optogalvanic signals were observed for each pathway. Results confirm the HCL as a cost effective spectroscopic investigation tool. In particular its use in the optogalvanic mode of operation allows one to precisely, easily and reliably tune the wavelength of one or more lasers to resonances of interest for experiments in the general domain of atomic vapour laser isotope selection (AVLIS). The measurements are closely related to the Selective Production of Exotic Species (SPES) project at the ISOL facility and were performed in the recently established laser laboratory in Legnaro National Laboratories of INFN.

The Changing International Situation and Chinas Concept of Peripheral Diplomacy in the Context of the Epidemic

The COVID-19 virus has not just changed the mode of operation and way of life of all humanity, but has profoundly transformed the entire world, from the global political structure and economic environment to the models and methods of regional economic development. It has significantly influenced the content and timing of the Fourth Industrial Revolution, impacting the international situation and the implementation of inter-state relations. In this context, China, adhering to the five basic principles of peaceful coexistence, aims to enrich the diplomatic concept of «benevolence, sincerity, mutual benefit and inclusiveness» in relations with neighboring states in order to strengthen and deepen them. The article puts a special emphasis on Chinese-Russian relations. It argues that the priority tasks for the leadership of the two countries should include: developing options for generating new production chains; taking into account the widening «gap between poor and rich» countries, as well as changes in the global political landscape. The implementation of these tasks can act as a stabilizing factor for regional and international development, guarantee secure borders and become a shining example of inter-state relations for the rest of the neighboring countries.

COMPUTER PROCEDURE FOR SELECTING PARAMETERS OF THE PERIPHERAL DOCKING ASSEMBLY LATCH MECHANISM

When developing the country’s made peripheral docking assembly consistent with the International Docking System Standard a task arose concerning reduction of dimensions of the latch mechanisms that ensure the capture. The article describes the mode of operation of these mechanisms. Proposed is a procedure which makes it possible to choose such a layout of their joints in which the links are inside a given area during operation. A uniform LPτ-sequence is used to form various options of the joints layout. A criterion of maximum loads acting on the links is described. It is shown that the dimensions of the existing latch mechanism can be decreased only with an increase of the load-carrying capability of the links. The proposed procedure is part of a software tool computerizing the design of a new latch mechanism. Key words: spacecraft docking, peripheral docking assembly, latch mechanism, capture, LPτ-sequence.

Use of exponential distribution in mathematical models of dependability

The exponential distribution of time to event or end of state is popular in the dependability theory. This distribution is characterized by the strength that is a convenient parameter used in mathematical models and calculations. The exponential distribution is used as part of dependability-related process simulation. Examples are given to illustrate the applicability of the exponential distribution. Aim. The aim of the paper is to improve the dependability-related simulation methods when using the exponential distribution of periods of states or times to events. Methods. The assumption of the exponential distribution of time between events can be justified or discarded using methods of the probability theory and/or mathematical statistics or on the basis of personal or engineering experience. It has been experimentally established that the failure flow in an established mode of operation is stationary, ordinary and produces no consequences. Such flow is Poisson and is distinct in the fact that the time between two consecutive failures is distributed exponentially with a constant rate. This exponential distribution is reasonably extended to the distribution of an item’s failure-free time. However, in other cases, the use of exponential distribution is often not duly substantiated. The methodological approach and the respective conclusions are case-based. A number of experience-based cases are given to show the non-applicability of exponential distribution. Discussion. Cases are examined, in which the judgement on the applicability or non-applicability of exponential distribution can be made on the basis of personal experience or the probability theory. However, in case of such events as completion of recovery, duration of scheduled inspection, duration of maintenance, etc., a judgement regarding the applicability of exponential distribution cannot be made in the absence of personal experience associated with such events. The distribution of such durations is to be established using statistical methods. The paper refers to the author’s publications that compare the frequency of equipment inspections with regular and exponentially distributed periods. The calculated values of some indicators are retained, while for some others they are different. There is a two-fold difference between the unavailability values for the above ways of defining the inspection frequency. Findings and conclusions. The proposed improvements to the application of exponential distribution as part of dependability simulation come down to the requirement of clear substantiation of the application of exponential distribution of time between events using methods of the probability theory and mathematical statistics. An unknown random distribution cannot be replaced with an exponential distribution without a valid substantiation. Replacing a random time in a subset of states with a random exponentially distributed time with a constant rate should be done with an error calculation.

Arbitration Hearing with Remote Participation: Necessary Innovations that Irreversibly Change Traditions

The COVID-19 coronavirus pandemic forced most arbitration centers in countries with a wide variety of legal traditions to switch to mass arbitration hearings in video conferencing mode in the spring of 2020. It turned out that hearings with remote participation of representatives of the parties, and sometimes arbitrators, have a number of advantages compared to regular hearings. A number of new possibilities arises and thus compensates the loss of certain possibilities adherent in physical presence of arbitration participants at hearings. The authors argue that most of the obstacles and shortcomings of the new format as a whole can be overcome with modern regulatory development, law enforcement, software, and hardware tools. The paper examines, among other things, the experience of the Arbitration Center at the Russian Union of Industrialists and Entrepreneurs, whose software and hardware complex and previously modernized arbitration rules made it possible to safely switch to a new mode of operation. New documents of international origin in this area are also being considered, indicating the need to ensure a balance between the effectiveness of arbitration proceedings on the one hand and the right of the parties to due process and fair treatment on the other.The authors conclude that there will not be a complete return to the previous practice with the end of the pandemic. However, a certain part of the meetings, taking into account the circumstances of the disputes, will return offline, the popularity of various mixed (hybrid) options will increase, which will not be difficult to put into practice due to the flexibility of the arbitration procedure. The flexibility of arbitration and the delegation to arbitrators of a number of issues related to the organization and conduct of arbitration proceedings, which require that opinions of the parties should be requested and considered in order to solve the dispute, makes it possible to ensure the optimal “format” of the arbitration procedure given the specific circumstances of the dispute. This procedure provides its participants, among other things, a reasonable and sufficient opportunity to present their positions, ensuring equal treatment of the parties and adversarial while ensuring the real effectiveness of the arbitration procedure, which allows in modern conditions to properly implement the principles on which arbitration is based.

EXPERIMENTAL STUDIES OF HEAT EXCHANGE DURING WATER COOLING AND STEAM CONDENSATION IN DEMOVER RADIATOR SECTIONS

The Department of Railwayand Road Transport, lift and care system of Volodymyr Dahl East Ukrainian National University, an energy-saving cooling system for diesel locomotives using phase transitions of the coolant has been developed. The proposed cooling system allows to maintain constant optimal temperatures of cooling objects at ambient temperatures ± 40 ºC and in any mode of operation of the diesel engine. For thermal calculation of the radiator section operating in the mode of the steam condenser, the mathematical model of process of heat transfer from steam to walls of a flat tube at condensation is developed that considers geometrical features of section of a tube. The adequacy of this mathematical model is verified by comparing the simulation results with the obtained experimental data. During the tests, the outlet water temperature, inlet and outlet air temperature, and air pressure in front of and behind the radiator were measured. Having the values of wall temperature, steam temperature and condensate, knowing the value of steam consumption and the experimental heat transfer coefficient, it becomes possible to verify the adequacy of the mathematical model by comparing the simulation results with the obtained experimental data. Schemes of bench equipment, test methods, experimental planning and basic calculation dependences required for testing serial radiator sections of a locomotive in the standard mode of operation and in the mode of steam condensers are presented.

Control of thermal regime of thermoelectric coolers in uniform temperature field

The comparative analysis of means of control of a thermal mode at minimization of a complex of the basic parameters in various combinations with indicators of reliability and dynamics of functioning of one-stage thermoelectric cooler is resulted. The study was conducted for the operating range of temperature differences, standard heat load and different geometry of the branches of thermocouples. According to the results of research to minimize the sets of basic parameters in interaction with the indicators of reliability and dynamics of work, a number of current modes of operation have been developed. The developed mathematical models for the optimal operating current from the relative temperature difference and heat transfer of the radiator for the proposed operating modes are analyzed. The results of calculations of the main parameters, reliability indicators, and time of transition to stationary mode of operation for different current modes of operation in the range of temperature differences for different geometry of branches of thermoelements are given. The extremes of dependences of the cooling coefficient, heat dissipation capacity of the radiator, the amount of energy consumed on the relative operating current are determined, which is essential for the implementation of the control function. The possibility of choosing the current mode of operation for optimal control of the thermal regime of single-stage thermoelectric devices manufactured by the same technology, taking into account mass, size, energy, reliability and dynamic characteristics. The developed method of optimal regulation of the thermal regime of a single-stage thermoelectric cooler based on minimizing the set of basic parameters allows finding and choosing compromise solutions taking into account the importance of each of the limiting factors.

Path Planning for Bulldozers with Curvature Constraints

There is presently no solution to the problem of an autonomous bulldozer pushing mounds of material to desired goal locations in the presence of obstacles whilst obeying the kinematic constraints of the bulldozer. Past work has solved some aspects of this problem, but not all. This research presents the first complete, practical solution to the problem. It works by creating a fixed RRT in advance, and then during operation connecting pushing poses into this RRT using Bezier curves. The RRT algorithm leverages a novel data structure for performing nearest neighbour comparisons for Ackermann-steering vehicles; termed the Distmetree. The resulting pushing states are searched using greedy heuristic search to find a solution and the final path is smoothed with cubic Bezier curves. The mode of operation chosen for best performance also constructs bidirectional RRTs to reach difficult to access pushing poses. The final mode of the algorithm was tested in simulation and proven to be able to solve a wide variety of maps in a few minutes while obeying bulldozer kinematic constraints. The algorithm, whilst not optimal, is complete which is the more desirable property in industry, and the solutions it produces are both feasible and reasonable.

Path Planning for Bulldozers with Curvature Constraints

There is presently no solution to the problem of an autonomous bulldozer pushing mounds of material to desired goal locations in the presence of obstacles whilst obeying the kinematic constraints of the bulldozer. Past work has solved some aspects of this problem, but not all. This research presents the first complete, practical solution to the problem. It works by creating a fixed RRT in advance, and then during operation connecting pushing poses into this RRT using Bezier curves. The RRT algorithm leverages a novel data structure for performing nearest neighbour comparisons for Ackermann-steering vehicles; termed the Distmetree. The resulting pushing states are searched using greedy heuristic search to find a solution and the final path is smoothed with cubic Bezier curves. The mode of operation chosen for best performance also constructs bidirectional RRTs to reach difficult to access pushing poses. The final mode of the algorithm was tested in simulation and proven to be able to solve a wide variety of maps in a few minutes while obeying bulldozer kinematic constraints. The algorithm, whilst not optimal, is complete which is the more desirable property in industry, and the solutions it produces are both feasible and reasonable.