Study of the impact of a new hurdle technology composed of electro‐activated solution and low heat treatment on the canned pea and corn quality and microbial safety

The objective of this work was to evaluate the quality of sterilised canned pea and corn in electro‐activated brine solutions at moderate temperatures. The lowest change in vitamin C was associated with the lowest heat treatment, while the short treatment time resulted in significant changes in texture and colour of vegetables. Best texture profile was obtained with the acid electro‐activated brine solution for pea and corn. The neutral electro‐activated brine solution resulted in a less firm texture for pea and corn. The green colour and brightness of canned pea were higher when neutral solution was used (a* = ?8.4 ± 0.3) than for the acidic one (a* = ?3.7 ± 0.6). The yellowness of corn was better with the neutral electro‐activated brine solution (b* = 36.32 ± 1.24) than with the acidic one (b* = 28.44 ± 2.39). Thirty‐three percent decrease of energy consumption was obtained using the electro‐activation technology.     

Chemical reactions in spherically symmetric problems of mechanochemistry

A stress-assisted chemical reaction front propagation in a linear elastic solid is considered. The reaction between gas and solid constituents is sustained by the diffusion of the gas through the transformed material. The consideration is based on the kinetic equation in a form of the dependence of the reaction front velocity on the normal component of the chemical affinity tensor that in turn depends on stresses and gas concentration. Spherically symmetric problems of mechanochemistry are solved for the reaction front propagation in a sphere, in a body with a spherical hole and in an inclusion placed into an infinite medium. It is demonstrated how stresses can enhance, retard and even lock the reaction. The effects of the sign and value of the reaction front curvature are also examined.     

Resource potential for wind-hydrogen power in Ukraine

The paper provides an assessment of the current wind energy potential in Ukraine, and discusses developmental prospects for wind-hydrogen power generation in the country. Hydrogen utilization is a highly promising option for Ukraine's energy system, environment, and business. In Ukraine, an optimal way towards clean zero-carbon energy production is through the development of the wind-hydrogen sector. In order to make it possible, the energy potential of industrial hydrogen production and use has to be studied thoroughly.Ukraine possesses huge resources for wind energy supply. At the beginning of 2020, the total installed capacity of Ukrainian wind farms was 1.17 GW. Wind power generation in Ukraine has significant advantages in comparison to the use of traditional sources such as thermal and nuclear energy.In this work, an assessment of the wind resource potential in Ukraine is made via the geographical approach suggested by the authors, and according to the «Methodical guidelines for the assessment of average annual power generation by a wind turbine based on the long-term wind speed observation data». The paper analyses the long-term dynamics of average annual wind speed at 40 Ukrainian weather stations that provide valid data. The parameter for the vertical wind profile model is calculated based on the data reanalysis for 10 m and 50 m altitudes. The capacity factor (CF) for modern wind turbine generators is determined. The CF spatial distribution for an average 3 MW wind turbine and the power generation potential for the wind power plants across the territory of Ukraine are mapped.Based on the wind energy potential assessment, the equivalent possible production of water electrolysis-derived green hydrogen is estimated. The potential average annual production of green hydrogen across the territory of Ukraine is mapped.It is concluded that Ukraine can potentially establish wind power plants with a total capacity of 688 GW on its territory. The average annual electricity production of this system is supposed to reach up to 2174 bln kWh. Thus, it can provide an average annual production of 483 billion Nm³ (43 million tons) of green hydrogen by electrolysis. The social efficiency of investments in wind-hydrogen electricity is presented.     

On a neutron detector based on TlInSe<Subscript>2</Subscript> crystals intercalated with a lithium isotope

The possibility of increasing the sensitivity of a neutron detector based on a TlInSe₂ crystal by introducing the ⁶Li isotope into this crystal is investigated. Introduction of the isotope is conducted by the method of electrochemical intercalation from aqueous and nonaqueous solutions of LiCl and also from the melt of the LiCl–KCl eutectic. It is shown that intercalation by the electrochemical method from a LiCl solution in propylene carbonate, performed along the “c” axis of the crystal (along strong bond chains) is efficient. The attained concentration of introduced lithium amounts to (1–1.2) × 10²¹ cm^–3, which increased the sensitivity of the detector by approximately four times. Good agreement between the calculated and experimental values of the detector sensitivity is demonstrated.     

Wear resistance of coatings manufactured by electric spark plating with Al-Sn electrodes

The effect of the anomalously high wear of the quenched steel counterbody was found during the testing of coatings manufactured by electric spark plating (ESP) with an AlSn alloy (20 wt % Sn). The presence of SnO₂ nanofibers in the coating composition, which are formed during the ESP with an electrode tool made of this alloy, is assumed to be the main reason for the above effect.     

Laser spark propagation along the beam in stationary gases at low pressures

A study of space-time evolution of the laser spark induced with the Nd: YAG laser in stationary gases at low pressures has been realized with the aid of high-speed photography. A mechanism to explain light propagation along the beam is proposed. Calculated data are in a good agreement with the experimental ones. The article was translated by the authors.     

Design-theoretical study of cascade CO2 sub-critical mechanical compression/butane ejector cooling cycle

In this paper an innovative micro-trigeneration system composed of a cogeneration system and a cascade refrigeration cycle is proposed. The cogeneration system is a combined heat and power system for electricity generation and heat production. The cascade refrigeration cycle is the combination of a CO₂ mechanical compression refrigerating machine (MCRM), powered by generated electricity, and an ejector cooling machine (ECM), driven by waste heat and using refrigerant R600. Effect of the cycle operating conditions on ejector and ejector cycle performances is studied. Optimal geometry of the ejector and performance characteristics of ECM are determined at wide range of the operating conditions. The paper also describes a theoretical analysis of the CO₂ sub-critical cycle and shows the effect of the MCRM evaporating temperature on the cascade system performance. The obtained data provide necessary information to design a small-scale cascade system with cooling capacity of 10 kW for application in micro-trigeneration systems.     

Phenomena at three-phase electroslag remelting

The electroslag remelting (ESR) process is widely used to produce high-quality ingots and billets for high-alloyed steels and alloys.Both the single-phase and three-phase alternating current diagram with bifilar and monofilar connection are in use for heavy ingot manufacturing.The numerical simulation of the three-phase bifilar circuit for the 120 t three-phase bifilar six-electrode ESR furnace at different variants of electric connection was presented and discussed.At the bifilar diagram of power supply,the geometrical location of electrodes in a mould holds critical importance for performances:the close location of bifilar pair electrodes provides the highest heat productivity,but the equidistant location of electrodes gives a much more uniform heat distribution.The monofilar mulit-electrode diagram of three-phase connection without phase shift shows the most uniform distribution of potential and heat generation as well as a favorable magnetic field that makes this kind the most promising for providing a high quality of heavy ingots.     

Base cations and micronutrients in forest soils along three clear-cut chronosequences in the northeastern United States

Determining effects of clear-cutting on base cations and micronutrients is essential for ensuring the sustainability of forestry for biofuels and wood products. The objective of this study was to quantify long-term changes in forest floor and mineral soil base cations (Ca, Mg, and K) and micronutrient (Mn, Zn, and Cu) concentrations and pools following clear-cutting in forests aged 1–120 years. We studied forest soils along three clear-cut chronosequences located in the Adirondack Ecological Center in Newcomb, NY, Bartlett Experimental Forest in Bartlett, NH, and Harvard Forest in Petersham, MA. We utilized a strong-acid extraction to quantify base cations and micronutrient concentrations and pools, which may better assess nutrients over the chronosequences than the conventional exchangeable extraction. Generalized linear mixed-effect models (GLMMs) show forest floor and mineral soil Ca, Mg, Mn, and Cu concentrations and pools decreased with increasing forest age across the three study areas. Potassium and Zn concentrations and pools were not significantly different with stand age and neither did soil C and N pools and pH using GLMMs. We calculated that 32–67% of the Ca pool decrease can be attributed to uptake by regenerating vegetation but only 0.02–9% of Mg, Mn, and Cu after harvest. Thus, leaching was likely to the dominant loss process for Mg, Mn, and Cu following clear-cutting. Our results suggest nutrient pools decreased for over a century following clear-cutting, but it is unclear if this will impact plant growth.     

Comparing finite state machine test

To plan testing activities, testers face the challenge of determining a strategy, including a test coverage criterion that offers an acceptable compromise between the available resources and test goals. Known theoretical properties of coverage criteria do not always help and, thus, empirical data are needed. The results of an experimental evaluation of several coverage criteria for finite state machines (FSMs) are presented, namely, state and transition coverage; initialisation fault and transition fault coverage. The first two criteria focus on FSM structure, whereas the other two on potential faults in FSM implementations. The authors elaborate a comparison approach that includes random generation of FSM, construction of an adequate test suite and test minimisation for each criterion to ensure that tests are obtained in a uniform way. The last step uses an improved greedy algorithm.