Rotational propulsion enabled by inertia

The fluid mechanics of small-scale locomotion has recently attracted considerable attention, due to its importance in cell motility and the design of artificial micro-swimmers for biomedical applications. Most studies on the topic consider the ideal limit of zero Reynolds number. In this paper, we investigate a simple propulsion mechanism --an up-down asymmetric dumbbell rotating about its axis of symmetry-- unable to propel in the absence of inertia in a Newtonian fluid. Inertial forces lead to continuous propulsion for all finite values of the Reynolds number. We study computationally its propulsive characteristics as well as analytically in the small-Reynolds-number limit. We also derive the optimal dumbbell geometry. The direction of propulsion enabled by inertia is opposite to that induced by viscoelasticity

The russian agricultural sector in the innovative component of the country’s food security

Achieving competitiveness in the global world economy system requires strengthening the innovative direction of representatives of the domestic agro-industrial sector. The innovative component of the agricultural sector also plays an important role in solving the country’s food security. The article considers the basics of the development of innovative activity of agro-industrial enterprises and the impact of innovative activity in the agro-industrial complex on the country food security. Obstacles are analyzed and priority directions of innovative development of agro-industrial enterprises are reflected

Observations of continuum depression in warm dense matter with X-ray thomson scattering

Detailed measurements of the electron densities, temperatures, and ionization states of compressed CH shells approaching pressures of 50 Mbar are achieved with spectrally resolved x-ray scattering. Laser-produced 9 keV x-rays probe the plasma during the transient state of three-shock coalescence. High signal-to-noise x-ray scattering spectra show direct evidence of continuum depression in highly degenerate warm dense matter states with electron densities ne>1024cm-3. The measured densities and temperatures agree well with radiation-hydrodynamic modeling when accounting for continuum lowering in calculations that employ detailed configuration accounting