Ice jams in rivers often arise from the movement of frazil ice as cover-load under ice cover, a process which is conceptually similar to the movement of sediment as bed-load along a river bed. The formation and movement of an iceaccumulation wave is one facet of a larger class of cover-load movements. The movement of an ice-accumulation wave obviously plays a crucial role in the overall process of ice accumulation. In the present study, experiments under different flow and ice conditions help reveal the mechanics of formation and evolution of ice-accumulation waves. In particular, suitable criteria for formation of an ice-accumulation wave are investigated along with the resulting speed of wave propagation. The transport capacity of frazil ice under waved accumulation is modeled by comparing those of experiments collected in laboratories, and the resulting equation is shown to be in good agreement with measured experimental results.
The paper deals with the calibration methods for machines with parallel kinematics. The procedures are based on Newton method for numerical solution of overconstrained system of nonlinear equations. The methods are applied on redundantly actuated machine with planar kinematics named ‘Sliding Star‘. The redundant measurements of relative motions in joints allow on-line calibration in real time of machine tool operation. This could significantly improve the thermal inaccuracy of machine tools with parallel mechanisms. and Obsahuje seznam literatury
So far, great efforts have been made to understand the demands
of extremely premature neonates (EPNs´; born before
the 28th week of gestation) on postnatal care, including optimal
oxygen saturation, that will allow them to survive without disability.
A major yet unresolved problem is to find an “optimal range” of
their oxygen saturation and to maintain it without drops or
increases, i.e., without hypoxia or hyperoxia. The individual
sections of this paper deal with the changes of SpO2 (an estimate
of SaO2 measured by pulse oximetry) that occur before, during,
and after premature labor, postnatal factors affecting SpO2, and
especially how to find an acceptable compromise in choosing the
most effective and minimally harmful range of SpO2 for EPNs’ with
the careful FiO2 adjustment and continually monitored SpO2. At
present, the two SpO2 ranges, narrow (90-94 %) vs. wider
(88-94 %), are most discussed. However, the question of how
much oxygen is too much or little remains unanswered. There is
even a view that there is no uniform optimal SpO2 range for EPNs,
and that each newborn has its own, individually specific range that
changes due to its intrinsic and/or extrinsic factors.