Predicting the average size of blasted rocks in aggregate quarries using artificial neural networks

The prediction of the average size of fragments in blasted rock piles produced after blasting in aggregate quarries is essential for decresing the cost of crushing and secondary breaking. There are several conventional and advanced processes to estimate the size of blasted rocks. Among these, the empirical prediction of the expected fragmentation in most cases is carried out by Kuznetsov’s equation (Sov Min Sci 9:144–148, 1973), modified by Lilly (1986) and Cunningham (1987). The present research focuses on the effect of the engineering geological factors and blasting process on the blasted fragments using a more powerful, advanced computational tool, an artificial neural network. In particular, the blast database consists of the blastability index of limestone on the pit face, the quantities of the explosives and of the blasted rock pile, assessing the interaction of these parameters on the blasted rocks. The data were collected from two aggregate quarries, Drymos and Tagarades, near Thessaloniki, in the Central Macedonia region of Greece. This approach indicates significant performance stability, providing the fragmentation size with high accuracy.

     

Multistable bridge element for pulse counters

Conclusions The above circuit can be used as a multistable pulse-position storage element in designing decimal counting decades for digital and computer devices, and also a frequency divider with a large ratio from 2 to 100.By utilizing the stabilizing properties of the bridge circuit, the scaling factor is maintained at a constant value in the temperature range of –20 to + 60°C with supply voltage variations of ±2% and replacement of circuit components.Bearing in mind the advantages and simplicity of this circuit it is advisable to organize mass production of such elements with integrated microcircuits.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 41–43, October, 1973.     

Measuring the resistance of resistors in the winding process with insulated wire

A method for measuring the resistance of resistors and dividers in the process of their winding using an insulated wire, along with their resistance distribution onto a frame according to a preset law, is proposed. The theory, error analysis, and possibilities of the method are studied.