Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

Experimental modeling of the microalgae cultivation in a photobioreactor using manure

The article studies the experimental process of cultivation of microalgae in a photobioreactor (PBR) to study the effect of technological conditions on the productivity of microalgae. This process allows obtaining initial data for the development of closed cycles of using the energy potential of alga mass in heat and power supply of various industries, including agricultural enterprises (livestock complexes, poultry farms, etc.) The scheme of a closed cycle of power supply of the cattle complex allows obtaining hot water, feed additives to the cattle ration, bio humus, motor biofuel and carbon dioxide, which is advisable to use in the process of cultivating microalgae. The experiments were carried out on a photobioreactor for cultivating microalgae with an intelligent control system. The developed photobioreactor differs from the known ones in the pulsating hydrodynamic regime of feeding the nutrient solution, which provides an increase in the productivity of the microalgae cultivation up to 15%. The experimental model of the cultivation conditions of the microalga Ch. Vulgaris on a combined diet (Tamiya medium + manure substrate) showed a noticeable increase in crop productivity when adding cattle manure extract to the nutrient medium in an amount from 30 to 60% (vol.). This can be used in the development of closed cycles of heat and power supply for cattle farms based on biofuels of the third generation, obtained from the phytomass of microalgae