Přenos tepla napříč superizolacemi z pokojových do nízkých teplot

For more than 30 years thermal measurement results and analytical formulas are available to calculate the heat transfer through Super Insulation (SI). According to the temperature dependence of the emissivity for aluminium, the most commonly used material for the reflecting surfaces, derivations based on the Stefan-Boltzmann-Law for radiative heat transfer have been established. Together with conductive terms this leads to formulas for the calculation of heat transfer through SI. Using new measurement results of temperature-dependent emissivity and conductivity we have performed heat flux calculations applying common software tools. The heat transfer through the SI and the temperature distribution inside the SI calculated with this new approach has been compared with the established formulas and measurement results

Evidence based neonatal surgery

Surgical intervention has, quite rightly, a well-established role in the management of a number of congenital and acquired neonatal conditions. Surgical approaches have been developed over a period of time, from the initial endeavours of pioneering neonatal surgeons, to the procedures commonly in everyday use today. Such development has been predominantly a result of necessity, learning from past experience and translation of techniques in use in other surgical fields into neonatal surgery. As neonatal surgical experience has grown, surgeons have begun to develop alternatives to what were once thought to be traditional techniques such that for a number of conditions we now have the luxury of choice in the treatment of these often fragile infants. With choice, there comes a dilemma. Which approach should be used? How should we make the decision