Weak magnetism phenomena in heavy-fermion superconductors: selected μ\muSR studies

The behavior of the so-called weak moment antiferromagnetic states, observed in the heavy-fermion superconductors UPt$_3$ and URu$_2$Si$_2$, is discussed in view of recent $\mu$SR results obtained as function of control parameters like chemical substitution and external pressure. In UPt$_3$, the Pd substitution for Pt reveals the dynamical character of the weak moment order. On the other hand, $\mu$SR measurements performed on samples in which Th substitutes U suggest that crystallographic disorder on the magnetic sites deeply affects the fluctuation timescale. In URu$_2$Si$_2$, a phase separation between the so-called hidden order state, present at ambient pressure, and an antiferromagnetic state, occurring under pressure, is observed. In view of the pressure-temperature phase diagram obtained by $\mu$SR, it is deduced that the respective order parameters have different symmetries.Comment: To appear in: J. Phys.: Cond. Matte

Design Considerations for Double-Skin Facades in Hot and Humid Climates

Thermal building simulations (TRNSYS) were linked to nodal airflow network simulations (COMIS) for a ventilated double-skin facade performance calculation and overall energy consumption for office building facades. Simulation results show good agreement with measured data. Especially interesting was the attempt to reduce the high peak cooling loads during the summer period by controlling the exhaust airflow using a climate sensitive regulator. It is shown that up to 26% reduction of annual cooling load can be achieved. This results in significant energy conservation and a reduction in system cooling size