Development of a dedicated isotope mass spectrometer for the noninvasive diagnostics of humans infected with Helicobacter Pylori

A dedicated isotope mass spectrometer for the noninvasive diagnostics of humans infected with Helicobacter Pylori using the isotope respiratory test is developed. A low-aberration mass analyzer is calculated, an input system that makes it possible to eliminate the memory effects is developed, and a small-size ion detector is constructed. The mass spectrometer is created, and the tests are performed. The measurement accuracy of the ¹³C/¹²C and ¹⁶O/¹⁸O isotope ratios are 1.7 and 2.2‰, respectively. Preliminary medical tests show that the spectrometer can be employed for the desired diagnostics.     

Stability analysis of rectangular plates unidirectionally strengthened by ribs

The exact solution of the equations of neutral equilibrium is derived. The effect of the discrete arrangement of ribs on the behavior of the characteristics of the stress-strain state with distance from the plate edge is analyzed. The conditions of applicability of the theory of structurally orthotropic plates are formulated. The study was carried out in accordance with Project No. 614 of the Ukrainian Scientific and Technological Center. S. P. Timoshenko Institute of Mechanics, National Academy of Sciences of Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 36, No. 4, pp. 132–136, April, 2000.     

Effect of shear deformation on stability of multilayered orthotropic ribbed cylindrical shells

S. P. Timoshenko Institute of Mechanics, Academy of Sciences of the Ukraine, Kiev. Translated from Prikladnaya Mekhanika, Vol. 30, No. 4, pp. 91–96, April, 1994.     

Natural Vibrations of Ribbed Cylindrical Shells with Low Shear Stiffness

A technique is proposed to determine the natural frequencies of rib-reinforced cylindrical shells with low shear stiffness. The equations of motion based on the Timoshenko model are used. The influence of the transverse shear moduli of the shell and ribs on the minimum natural frequencies and corresponding modes is studied by way of numerical examples. It is shown that the effect of the discrete ribs is different from that predicted by the classical theory of ribbed shells__________Translated from Prikladnaya Mekhanika, Vol. 41, No. 4, pp. 66–74, April 2005.     

Vibrations and Stability of Shallow Ribbed Shells with a Rectangular Planform

A technique is developed to determine the critical stresses and natural frequencies of shallow ribbed shells with a rectangular planform and the corresponding buckling wave and natural modes. The effect of discrete rib arrangement on these characteristics is studied by numerical examples.