Vol 111, No 4 (2022)

This article highlights the prerequisites and natural effects of control method development in engineering systems: (1) a simple deviation and perturbation controller, (2) a fuzzy logic controller with a fuzzifier and rule base, (3) a neural network controller for dynamically adjusting the coefficients of the corresponding links, (4) a discrete neural network controller with a neural approximator and controller. The experience gained by researchers and engineers since the initial description of regulatory principles in 1910, including the level of information technology design, particularly the neural network approach to machine learning and the enormous computing potential of computer devices, now enable the integration of a fundamentally novel method of discrete neural network regulation.

The article’s review aims to identify and demonstrate the importance of experimental and operational data, which must be organized and annotated at the time of collection and archiving. This approach will allow us to rapidly implement neural network controllers in engineering systems, as the most critical phase in their development is involves learning and optimization of neural network architecture.

The article presents the principle of operation, benefits, and drawbacks, and the optimal stages for enhancing a neural network controller based on two neural networks, which form a control strategy while considering the most probable state of the system at the next point in time.

This article reviews cold storage technologies that use slurry ice in air-conditioning systems. The authors try to focus attention on an environmentally friendly technology that improves the energy efficiency of air-conditioning systems.

This article discusses systems with coolants, highlights their main types, and lists the main advantages and disadvantages of using two-phase coolants. Because the use of water as a coolant below 0 °C requires additional impurities, the main additives and depressants used in this technology for obtaining ice suspensions, as well as their effect on the properties of an aqueous solution of slurry ice, were considered. The authors studied and described the main methods for generating slurry ice, such as fluid subcooling, direct contact with an immiscible refrigerant, freezing on surfaces, obtaining an ice suspension in a fluidized bed, and «vacuum» ice. For each method, the principles of obtaining slurry ice and the main advantages and disadvantages are described. To more completely understand the design aspects of systems using slurry ice, the authors reviewed methods for storing and distributing an ice suspension in a system. Their scopes of application and the main differences between the use of centralized and decentralized slurry ice storage systems are described.

BACKGROUND: Spiral compressors are often used in refrigeration. They have high volumetric efficiency, low noise, high balance, and numerous other advantages. Public information describing the profiling of scroll is insufficient; thus, scroll profiling is the greatest difficulty facing scroll compressor designing.

AIM: A description of the plotting and profiling of the most common types of scrolls of refrigeration scroll compressors.

MATERIALS AND METHODS: The use of known mathematical relations and tools for developing calculation formulas.

RESULTS AND APPLICATIONS: The necessary mathematical equations are developed and described, and they allow us to profile and construct 3D models of a piecewise circular spiral, an involute spiral, and an Archimedean spiral.

The impact of local low-temperatures on biological tissues, depending on the temperature reached, can lead to destructive, preservation, or therapeutic effects. This paper takes a unified approach to the transition from general recommendations to personalized recommendations for the dosing of local low-temperature exposure. The exposure process is divided into three stages: planning, provision and control, and an analysis of compliance with the planned dose. Solutions to the problems of heat transfer in cryosurgery and cryopreservation are given to possibly improve the planning stage. In the framework of the first way, two cases are considered. The first case is to improve the accuracy of prostate cryoablation planning. The second case is to compare the effectiveness of various materials of cryosurgical applicators: copper, brass, and artificial sapphire, which can be used to influence and control the freezing zone by optical methods. In the framework of the second way, a case of using local low-temperature exposure to simultaneously preserve the framework of biological tissue and remove a layer of donor cells, called decellularization, is shown for transplantology. The results of the above examples can potentially be used to plan a local low-temperature impact. Thus, new-generation methods and technologies allowing accurate dosing can be developed.

Various types of physical exposures, including laser, electromagnetic, and cryogenic exposures, are used on living tissues and human organs to suppress pathology or effect destruction. The use of physical exposures is usually empirical. Nevertheless, experience confirms the promise of their use and indicates the need to study the characteristics of living tissues and the development of complex technologies for the application of physical effects. This paper describes the experience derived from their practical applications. They have many advantages over traditional treatment methods, including painlessness, an absence of bleeding and a generally noticeable reaction of the body, and a high functional effect. Local cryoablation using handheld portable cryosurgical devices and liquid nitrogen as a refrigerant (−196 °C) is a practically applicable method for treating simple hemangiomas and allows for obtaining good functional and cosmetic results. All types of simple small hemangiomas of any localization are subject to treatment, regardless of the age of the child. The proposed method allows for completely or partially refusing complex surgical interventions, particularly when placing small hemangiomas on the face, neck, and ear areas, and obtains good results (98%). Preliminary microwave irradiation and the use of a laser allow a 4- to 6-fold increase in the possibilities of cryotherapy along the depth of the hemangioma compared to simple cryoablation. This method retains all the useful features of cryoablation. It is promising for treating cavernous and combined hemangiomas, which have a pronounced subcutaneous part and often complex localization. This approach is potentially useful in other cryogenic applications.

In the context of adverse changes in the planet’s biosphere, such as environmental and atmospheric pollution, global warming, and depletion of energy resources, increasingly stringent criteria are imposed on manufacturers of refrigeration equipment. The most crucial of these criteria include: (a) enhancement of energy efficiency in refrigeration equipment; (b) reduction in material consumption of refrigeration units, and (c) use of “clean” and safe materials and refrigerants.

The Taiwanese company, Fusheng, has been a global leader in the production of screw refrigeration compressors for several decades. The company’s experts are constantly working to enhance the manufactured equipment and implement the most advanced technologies.

Recently, the most effective steps in this area have been the advancement and perfection of the manufacturing of specialized two-stage low-temperature screw compressors in the SRT series, as well as the production of compact screw compressors with an integrated BSR series oil separator. These compressors feature a variable compression ratio and semisealed screw refrigeration compressors with volumetric capacities ranging from 85 to 1946 m³/h

The SRT compressor series includes six models with first-stage volumetric capacities ranging from 120–759 m³/h and second-stage volumetric capacities ranging from 50–300 m³/h.