UTVRĐIVANJE UČINKOVITOSTI EKSPLOZIVA KOD IZVOĐENJA MINIRANJA

Experimental methods for determining a performance index of explosives are analysed: the methods of a ballistic pendulum, ballistic mortar, a lead block, and according to the volume of soil explosion funnel. It is defined that the determination of a performance index of emulsion explosives (EE) involves a set of significant features connected with a large critical diameter requiring the experiments with large-mass charges and resulting in refusal from the traditional methods of determining a performance index. Analytical methods for calculating an index of relative performance of explosives are analysed. Determination of the performance indices of explosives with the help of analytical methods helps identify considerable differences in the calculation results; in case of emulsion explosives the results are erroneously low at all. It is since analytical methods do not consider the brisant action of emulsion explosives. This paper represents the developed methodology of determining a performance index of explosives according to the degree of detonation velocity. The proposed methodology considers the key energy and detonation characteristics of explosives: heat and volume of the explosion products, density (thickness), and detonation velocity. The use of analytical methodology for calculating a performance index for all explosive types makes it possible to get correct results that are necessary for designing the parameters of drilling and blasting operations.U radu su analizirane eksperimentalne metode kojima se određuje indeks učinkovitosti eksploziva: metoda balističkoga klatna, metoda balističkoga mužara, Trauzlova proba i metoda određivanja volumena kratera od miniranja u tlu. Utvrđeno je kako određivanje indeksa učinkovitosti emulzijskih eksploziva (EE) uključuje skupinu važnih značajki povezanih s velikim kritičnim promjerom, a to zahtijeva ispitivanja s nabojima velike mase i odustajanje od tradicionalnih metoda određivanja indeksa učinkovitosti. Također, analizirane su analitičke metode za izračunavanje indeksa relativnoga učinka eksploziva. Određivanje indeksa učinkovitosti eksploziva uz pomoć analitičkih metoda pomaže identificirati znatne razlike u rezultatima, a rezultati su u slučaju emulzijskih eksploziva općenito preniski. Do toga dolazi zato što analitičke metode ne uzimaju u obzir brizantno djelovanje emulzijskih eksploziva. U radu je prikazana razvijena metodologija određivanja indeksa učinkovitosti eksploziva prema stupnju brzine detonacije. Predložena metodologija razmatra ključne parametre energije i detonacijskih svojstava eksploziva: toplinu i volumen produkata eksplozije, gustoću (promjer) i brzinu detonacije. Korištenje analitičke metodologije izračuna indeksa učinkovitosti kod svih vrsta eksploziva omogućuje dobivanje točnih rezultata potrebnih za određivanje parametara bušenja i miniranja

Evaluating elasticity of costs for employee motivation at the industrial enterprises

Employee motivation at the industrial enterprises is one of the most important principles of modern management. The practice of production and commercial activities of domestic enterprises speaks for essential modifications in the approaches to identifying the methods of employee motivation.In the meantime, at many industrial enterprises, motivational modules are limited to the level of salary payment. Therefore, the search for approaches to the formation of effective methods of employee motivation and the analysis of their classification peculiarities require implementing the complex scientific research and determine the relevance of the chosen topic. The purpose of the article is to adapt the notion of function elasticity to increase the employee motivation effectiveness at the domestic industrial enterprises. Increasing the effectiveness of employee motivation at an industrial enterprise is the object of the research.The research findings are obtained using the theory and practice of expert methods and system analysis, whereby 26 basic (key) motivational measures were determined, which were divided into six block-modules: jurisdictions, effectiveness, social and psychological, indirect financial influence, and direct financial influence.The weight of each of the motivational factors is determined and they were also classi¬fied according to this indicator. The notion of motivation elasticity is proposed, which makes it possible to assess the motivational measures performance both for every block-module and for every employee, team, production department or enterprise.Motivation elasticity ratio for ten employees of Kharkiv Machine Engineering Plant FED is calculated. Recommendations for further research on the paper’s subject are proposed

Raises advance using emulsion explosives

Using the well-known laws of the theory of elasticity and the basic principles of the quasi-static wave hypothesis of the mechanism of destruction of a solid medium by an explosion, methods have been developed for calculating the parameters of drilling and blasting (D&B) for raises advance using the methods of blast-hole and borehole charges. It has been established that the calculating D&B parameters is carried out in the same sequence as when drifting operation. To check the calculating D&B parameters using the new method during raise advance, a numerical simulation of changes in the stress-strain state of a rock mass under the influence of an explosion was carried out. According to the results of numerical simulation, the formation of zones of inelastic deformation in the face of a rising mine working under blast load, uniform grinding of the rock was obtained, which will avoid the release of oversized pieces after the explosion. The developed methodology was tested in the conditions of the “Yuvileina” mine of PJSC “Sukha Balka” during the raise advance of a 1420 m level using a sticked emulsion explosive (EE) Anemix P. Test explosions obtained good results in blasting the face of a raise, uniform crushing of the rock and a high coefficient of use of bore-holes has been established

Asymmetric snubberless current-fed full-bridge isolated DC-DC converters

This paper presents two isolated current-fed fullbridge DC-DC converters that can be used to interface a lower voltage source into a DC bus of higher voltage. The first topology uses a resonant circuit to force current redistribution between low-voltage-side transistors and a passive rectifier. The second topology utilizes an active rectifier with secondary modulation to achieve the same goal. The resonant circuit can be formed by using transformer leakage inductance and the parasitic capacitances of the switches. The converters feature soft switching of semiconductors over a wide range of operating conditions. This is achieved with decreased energy circulation when compared to existing topologies with symmetric control and with fewer semiconductors than in those with phase-shift control. The topologies can be implemented in renewable, supercapacitor, battery, fuel cell, and DC microgrid applications. Steady-state operation and design aspects of the converters are presented and verified experimentally with 400 W prototype

Comparative Analysis of Semiconductor Power Losses of Galvanically Isolated Quasi-Z-Source and Full-Bridge Boost DC-DC Converters

This paper compares semiconductor losses of the galvanically isolated quasi-Z-source converter and full-bridge boost DC-DC converter with active clamping circuit. Operation principle of both converters is described. Short design guidelines are provided as well. Results of steady state analysis are used to calculate semiconductor power losses for both converters. Analytical expressions are derived for all types of semiconductor power losses present in these converters. The theoretical results were verified by means of numerical simulation performed in the PSIM simulation software. Its add-on module “Thermal module” was used to estimate semiconductor power losses using the datasheet parameters of the selected semiconductor devices. Results of calculations and simulation study were obtained for four operating points with different input voltage and constant input current to compare performance of the converters in renewable applications, like photovoltaic, where input voltage and power can vary significantly. Power loss breakdown is detailed and its dependence on the converter output power is analyzed. Recommendations are given for the use of the converter topologies in applications with low input voltage and relatively high input current

Asymmetric Snubberless Current-Fed Full-Bridge Isolated DC-DC Converters

This paper presents two isolated current-fed full bridge dc-dc converters that can be used to interface a lower voltage source into a dc bus of higher voltage. The first topology uses resonant circuit to force current redistribution between low voltage side transistors and a passive rectifier. The second topology utilizes an active rectifier with secondary modulation to achieve the same goal. The resonant circuit can be formed by using transformer leakage inductance and parasitic capacitances of the switches. The converters feature soft switching of semiconductors over a wide range of operating conditions. This is achieved with decreased energy circulation when compared to existing topologies with symmetric control and with fewer semiconductors than in those with phase-shift control. The topologies can be implemented in renewable, supercapacitor, battery, fuel cell, and dc microgrid applications. Steady-state operation and design aspects of the converters are presented and verified experimentally with 400 W prototypes

Comparative Analysis of Semiconductor Power Losses of Galvanically Isolated Quasi-Z-Source and Full-Bridge Boost DC-DC Converters

This paper compares semiconductor losses of the galvanically isolated quasi-Z-source converter and full-bridge boost DC-DC converter with active clamping circuit. Operation principle of both converters is described. Short design guidelines are provided as well. Results of steady state analysis are used to calculate semiconductor power losses for both converters. Analytical expressions are derived for all types of semiconductor power losses present in these converters. The theoretical results were verified by means of numerical simulation performed in the PSIM simulation software. Its add-on module “Thermal module” was used to estimate semiconductor power losses using the datasheet parameters of the selected semiconductor devices. Results of calculations and simulation study were obtained for four operating points with different input voltage and constant input current to compare performance of the converters in renewable applications, like photovoltaic, where input voltage and power can vary significantly. Power loss breakdown is detailed and its dependence on the converter output power is analyzed. Recommendations are given for the use of the converter topologies in applications with low input voltage and relatively high input current

DETERMINING THE PERFORMANCE OF EXPLOSIVES FOR BLASTING MANAGEMENT

Experimental methods for determining a performance index of explosives are analysed: the methods of a ballistic pendulum, ballistic mortar, a lead block, and according to the volume of soil explosion funnel. It is defined that the determination of a performance index of emulsion explosives (EE) involves a set of significant features connected with a large critical diameter requiring the experiments with large-mass charges and resulting in refusal from the traditional methods of determining a performance index. Analytical methods for calculating an index of relative performance of explosives are analysed. Determination of the performance indices of explosives with the help of analytical methods helps identify considerable differences in the calculation results; in case of emulsion explosives the results are erroneously low at all. It is since analytical methods do not consider the brisant action of emulsion explosives. This paper represents the developed methodology of determining a performance index of explosives according to the degree of detonation velocity. The proposed methodology considers the key energy and detonation characteristics of explosives: heat and volume of the explosion products, density (thickness), and detonation velocity. The use of analytical methodology for calculating a performance index for all explosive types makes it possible to get correct results that are necessary for designing the parameters of drilling and blasting operations