Anna Kapranova is Head of the Department of Theoretical Mechanics and Resistance of Materials, Yaroslavl State Technical University, Russia. She is D. Sc. in the physical and mathematical field (direction - processes and devices of chemical technologies, 2009), has more than 300 scientific publications on the modeling of bulk materials processing and liquid flow processes, as well as over 50 patents of the Russian Federation. Her research area includes modeling the processing of bulk materials, (for example, the technical operations of mixing and deaeration of solid disperse media) and the transport of fluid flows.

The wide application of valves in large-scale chemical production requires an investigation of the conditions for the effective operation of the regulator. The actual design of new valves for fluid transportation is associated with theoretical studies in the modeling of cavitation bubble formation. The purpose is to investigate the effect of the degree of opening of the valve separator on the evolution of hydrodynamic cavitation. There are various constructive ways to combat the phenomenon of cavitation in regulating devices. Special devices, for example, movable or fixed separators, are installed to reduce the undesirable effects of cavitation in valve designs of the axial type. The stochastic model of bubble formation proposed by the authors earlier in the framework of the Ornstein-Uhlenbeck process allows us to take into account the change in the coefficient of hydraulic

resistance in the flow of liquid in the flowing part of the axial valve, depending on the design parameters of the separator and the regulating parameters of the device. The results of the simulation allow us to trace the dependence of the growth of cavitation bubbles being designed from the complex constructive-regime characteristic of the regulating organ (the ratio of the conditional area of the valve cross-section to the area of the cross-section of the separator). The practical application of the proposed method of accounting for the degree of opening of the separator in the framework of modeling the stationary and homogeneous Markov process is to develop a methodology for calculating the elements of the regulatory body.

Dieter Matthias Herlach studied physics at the RWTH Aachen and received the doctoral degree as Dr. rer. nat. at the same university. He became private lecturer upon a habilitation at the Ruhr-University Bochum RUB. Presently, he is the group leader at the Institute of Materials Physics in Space and Senior Scientist of the German Aerospace Center DLR. He is the full professor in physics at RUB. He has authored over 300 scientific publications in refereed journals. He is author and editor of six books and co-editor of Advanced Engineering Materials. He educated more than 30 PhD students and acted as supervisor of more than 20 diploma thesis works. Dieter Herlach led and leads projects of the German Research Foundation, the German Aerospace Center – Space Management, the European Space Agency and was the principal investigator of NASA during three Spacelab missions. He initiated and coordinated two priority programs of the German Research Foundation (DFG) and was a member of the International Advisory Committee of the Int. Conf. on Rapidly Quenched and etastable Materials. He is an honorary professor of three universities and was granted by the Chinese Friendship Award in Beijing in 2000 and the Lee Hsun Lecture award of the Chinese Academy of Sciences in 2007. He chaired the Division of Metal and Materials Physics of the German Physical Society DPG and was elected member of the council of DPG. He was elected member of the general review committee of DFG and deputy chairman of the German Society of Materials Science and Engineering.

An undercooled melt possesses an enhanced free enthalpy that gives access to crystallize metastable solids. Crystal nucleation selects the crystallographic phase whereas the subsequent crystal growth controls the microstructure evolution. Electromagnetic and electrostatic levitation techniques are very efficient to produce a highly undercooled melt since heterogeneous nucleation on container-walls is avoided. Moreover, a freely suspended drop is accessible for in situ observation of crystallization far away from equilibrium. We combine levitation technique with the diagnostic means of neutron scattering to investigate short-range order in undercooled melts and energy dispersive X-ray diffraction of synchrotron radiation to observe phase selection processes upon undercooling. Measurements of the statistics of nucleation undercooling are performed in order to study the physical nature of crystal nucleation. Nucleation is followed by crystal growth. In undercooled melts, the crystal grows with dendritic morphology since a planar interface is destabilized by the negative temperature gradient ahead of the solid-liquid interface. In highly undercooled melts dendrites propagate very rapidly. A high-speed camera is used to record the advancement of the solidification front. Dendrite growth velocities are measured as a function of undercooling of pure metals, solid solutions and intermetallics. Non-equilibrium crystallization effects are evidenced. Crystal growth is governed by heat and mass transport. To explore the influence of convection on dendrite growth comparative experiments in microgravity are performed using an electromagnetic levitator on board the International Space Station. Metals show dendritic growth in a mesoscopic scale with a rough interface at the microscopic scale. In case of semiconductors, the solidification front is facetted in a mesoscopic scale with a smooth interface on a microscopic scale. The entropy of fusion of the compound Ni2B is located in between that of metals and semiconductors. A transition from dendritic to facetted growth is observed induced by convection in the undercooled drops.