Asphalt concrete mixes are the primary construction material for road surfaces, and precise design of their composition plays a key role in the quality and durability of road pavements. This article discusses the challenges associated with designing asphalt concrete mix compositions and presents a developed system for automatic mix selection. The automatic asphalt concrete mix composition selection system is a powerful tool for optimizing the material selection process used in road construction. This system can calculate the optimal mix composition, taking into account technical and economic constraints, leading to increased accuracy and reliability in mix selection. The advantages of this system include reducing the time and cost of the selection process, enabling testing and analysis of various mix options, ultimately improving the quality and durability of road pavements.

Keywords: asphalt concrete, asphalt concrete mix, composition selection, least squares method, linear programming method, software, automation, Python, Microsoft Access

Classical implementation of active selective amplifiers (SA) are usually associated with design sophisticated active elements (operational amplifiers) that consume relatively large power from their universality. This paper present the active SA based on an analog array chip ABMK_1_3, that have high level of radiation resistance to the flow of neutrons and accumulated dose of radiation. This SA implemented on the basis of a voltage-to-current converter with a minimum number of transistors and low consumption static current. Efficient use of current amplifier can be explained by use frequency dependent symmetric chains in a feedback loop. This property provides the independence of the pole frequency f0 = fp on the gain of the active element, as well as maximizing the quality factor.
The basic analytical expressions that establish the relationships between the SA and the characteristics of active and passive components are given. The relations that help minimize sensitivity of parameters SA to instability properties of the components are considered. Simulation results of desired SA are shown.  

Keywords: selective amplifier, bandpass filter, active RC-filter, analog array chip, radiation hardness