Soft-Transition Sub-PCA Monitoring of Batch Processes

Batch or semi-batch processes have been utilized to produce high-value-added products in the biological, food, semi-conductor industries. Batch process, such as fermentation, polymerization, and pharmacy, is highly sensitive to the abnormal changes in operating condition. Monitoring of such processes is extremely important in order to get higher productivity. However, it is more difficult to develop an exact monitoring model of batch processes than that of continuous processes, due to the common natures of batch process: non-steady, time-varying, finite duration, and nonlinear behaviors. The lack of exact monitoring model in most batch processes leads that an operator cannot identify the faults when they occurred. Therefore, effective techniques for monitoring batch process exactly are necessary in order to remind the operator to take some corrective actions before the situation becomes more dangerous.

Using the Backward Probability Method in contaminant source identification with a finite-duration source loading in a river

Violation of industries in discharging their effluents into rivers leads to river pollution, which endangers the environment and human health. Appropriate tools are needed to deal with violations and protect rivers. The Backward Probability Method (BPM) is one of the most recommended tools identifying the release time and location of the pollutant source. However, the BPM generally was developed for groundwater and spill injection. Since most industries inject their effluents with a constant rate for a finite-duration, the use of prevailing models will have some errors. In this study, a numerical model was developed that could simulate a source with either a finite-duration or spill injection. This model is verified for two hypothetical cases and one real case. The results show that the model can accurately identify the release time and location of the pollutant source.

Synthesis of the transfer function of the voltage controller in an active filter-stabilizer converter

It has been established that in order to ensure effective filtration and stabilization of the voltage of DC traction substations, it is advisable to use active filters-stabilizers. The dynamic characteristics of an active filter-stabilizer have been analyzed taking into consideration its discrete properties. It has been shown that the voltage converter in an active filter-stabilizer with bilateral pulse-width modulation for small values of control signal increment is an amplitude-pulse modulator of the second kind. In order to improve the efficiency of using an active filter-stabilizer, which is part of the DC traction substation converter, the task was set to synthesize the transfer function of its converter's voltage controller. When analyzing a closed automatic control system, it was established that the transfer function of the voltage controller, which ensures the implementation of processes of finite duration in the closed automatic control system, includes a proportional part, an integral part, and a differential part. To determine the time constants for the transfer function of the PID-controller, as well as its damping coefficient, a closed automatic control system of the active filter-stabilizer voltage converter was investigated using an apparatus of Z-transformation. The result of synthesizing the transfer function of the voltage controller has established the parameters for the controller's transfer function, which ensure that the process of finite duration is executed in a closed system of automatic control over the converter's output voltage. The transition process in the system with a stepwise input effect of the processes of finite duration has been calculated, which confirmed that the transition process in the system ends after three clock intervals of discreteness. Establishing a transition process that ends over the finite number of discrete intervals, which is determined by the order of the characteristic equation, means that the process has been optimized for performance

High-latitude emission from the structured jet of γ-ray bursts observed off-axis

The X-ray emission of γ-ray burst (GRBs) is often characterized by an initial steep decay followed by a nearly constant emission phase (so-called “plateau”) which can extend up to thousands of seconds. While the steep decay is usually interpreted as the tail of the prompt γ-ray flash, the long-lasting plateau is commonly associated to the emission from the external shock sustained by energy injection from a long-lasting central engine. A recent study proposed an alternative interpretation, ascribing both the steep decay and the plateau to high-latitude emission (HLE) from a “structured jet” whose energy and bulk Lorentz factor depend on the angular distance from the jet symmetry axis. In this work we expand on this idea and explore more realistic conditions: (a) the finite duration of the prompt emission, (b) the angular dependence of the optical depth, and (c) the dependence of the light curve on the observer viewing angle. We find that, when viewed highly off-axis, the structured jet HLE light curve is smoothly decaying with no clear distinction between the steep and flat phases, as opposed to the on-axis case. For a realistic choice of physical parameters, the effects of a latitude-dependent Thomson opacity and finite duration of the emission have a marginal effect on the overall light-curve evolution. We discuss the possible HLE of GW170817, showing that the emission would have faded away long before the first Swift-XRT observations. Finally, we discuss the prospects for the detection of HLE from off-axis GRBs by present and future wide-field X-ray telescopes and X-ray surveys, such as eROSITA and the mission concept THESEUS.

DEVELOPMENT OF THEORETICAL PROVISIONS OF TRANSMISSION OF DISCRETE MESSAGES OF MILITARY RADIOCOMMUNICATION SYSTEMS

Modern military radio systems operate in the complex conditions of the electronic environment, due to the limited frequency range, the influence of deliberate interference and signal fading. One of the ways to improve the effectiveness of military radio communication systems is to develop indicators (methods, techniques) for evaluating the effectiveness of military radio communication systems. The analysis found that known approaches to evaluating the performance of military radio communications systems are based on the use of bit error probability in a channel, which is a rather rough indicator of channel estimation. This necessitates the development of theoretical provisions for the transmission of discrete messages to military radio systems. In order to improve the known theoretical provisions for the transmission of discrete messages of military radio communication systems, the authors of the article developed indicators for assessing the quality of functioning of military radio communication systems that operate in complex conditions of electronic conditions. In the course of the study, the authors of the research substantiated two indicators of link quality in the fading channel: the probability of correctly receiving a message of finite duration and the likelihood of a link of finite duration without breaks. The first metric is the overall metric (communication) quality of the communication, and the second metric is the quality of the channel in the session of the final duration. During the research, the authors used the basic principles of communication theory, theories of insecurity, the theory of transmission of discrete messages, etc. The proposed results can be used to evaluate the status of radio channels when they are exposed to a variety of origins and signal fading. The practical significance of these results is that they can be used to upgrade existing radios or to develop new ones by developing appropriate software