Structure of Macro- and Trace Elements Status Observed in Residents of Magadan Town

The authors aimed the study at examining macro- and trace elements content in elderly people of the 1 period of middle age （21-35） residing in Magadan town to assess the content of 25 trace elements in hair samples on individual and population levels by atom-emission spectrometry with inductively-bonded argon plasma. It turned out that the majority of surveyed subjects were characterized by deformation of element status demonstrated by excess and deficit of the basic essential elements of different degrees of manifestation. Deficit of Co （68% of surveyed people）, Mg （67%）, Ca （64%）, Cu （47%）, K （46%）, Zn （44%）, I （41%）, Na （33%）, P （27%） and Se （24%） was typical for female subjects as well as excess of Si （28%）, Zn （22%） and P （20%）. Male residents were characterized by deficit of Co （81%）, Ca （66%）, Mg （65%）, I （50%）, Cu （37%）, K and Na （27%） and excess of Zn （41%）. In individual cases it was noted excess concentration of nominally essential and toxic elements in both examined groups. They were： A1, As, Cd, Li, Ni, Pb, Sn, V and B. While analyzing of medians of chemical concentration it was stated reliable sex-related differences （P 〈 0.05）： content of Ca, Mg and Mn was higher in hair samples of women, and content of As, B, Cd, Cr, K, Li, Na, P, Pb and V, on the contrary, was higher in male samples.

Dynamic interaction between clustered liquid propellant rocket engines under their asynchronous start-ups

A nonlinear mathematical model of the low-frequency dynamics of the clustered multi-engine rocket propulsion system has been developed and the computations of the engine transient processes during the start-ups of the four-engine propulsion system with a shared feed system have been made applied.Based on propulsion system start-up modeling the influence of the connectivity of engines in a cluster on the starting characteristics of individual engines is shown.In particular,an advanced nonlinear mathematical model of the pump cavitation phenomena is a distinctive feature of the mathematical model.The computation results showed that the asynchronous engines start-ups during rocket lift-off lead to severely nonlinear engine transients and clustered engine thrust misbalance.The influence of the rocket engines asynchronous start-ups on the clustered feed system transients depends on many factors,mainly on from the clustered feed system low-frequency dynamics,the magnitude of the disturbance and the phase difference between disturbances acting on different branches of the feed system.The deep lingering dips in the flow rate and pressure transients are possible due to the nonlinear dynamic interaction of the engines.In case of great pressure dips at the pump inlet(up to the pressure of saturated vapors during significant periods of start-up time)the cavitation breakdowns of the pumps of one or more engines from the cluster are possible.This can disrupt the operation of the entire propulsion system and leads to the failure of the launch vehicle mission.