References of "Waldmann, Danièle 50003293"
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See detailPrimary energy used in centralized and decentralized ventilation systems measured in field tests in residential buildings
Merzkirch, Alexander UL; Maas, Stefan UL; Scholzen, Frank UL et al

in Proceedings of the 26th AIVC Conference, Effective Ventilation in high performance buildings (2015, September)

Ventilation systems can save heat energy by using heat recovery, but consume electrical energy to power the fans. In practice, the energy efficiency of those systems can be lower than expected, when ... [more ▼]

Ventilation systems can save heat energy by using heat recovery, but consume electrical energy to power the fans. In practice, the energy efficiency of those systems can be lower than expected, when compared to the nominal values provided by the manufacturer. In this paper, results of a comprehensive field tests with 20 centralized and 60 decentralized ventilation systems for residential buildings and the calculation of the primary energy savings of those devices are presented. Factors like volume flow unbalances, shortcuts, temperature change rates and specific fan power have been addressed by tracer gas technology and other means and been used as input factors to calculate the primary energy balance of those devices. Every system showed positive primary energy savings. The mean value for centralized systems was 2.92 Wh/m3 with a high standard deviation of 2.23 Wh/m3, while the decentralized systems showed higher savings of around 4.75 Wh/m3 with a standard deviation of 0.01 to 0.15 Wh/m3. In general, the calculated savings in field tests were significantly lower compared to the case of using nominal values as input parameters. [less ▲]

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See detailBiomechanical properties of five different currently used implants for open-wedge high tibial osteotomy
Diffo Kaze, Arnaud UL; Maas, Stefan UL; Waldmann, Danièle UL et al

in Journal of Experimental Orthopaedics (2015), 2(14),

Background: As several new tibial osteotomy plates recently appeared on the market, the aim of the present study was to compare mechanical static and fatigue strength of three newly designed plates with ... [more ▼]

Background: As several new tibial osteotomy plates recently appeared on the market, the aim of the present study was to compare mechanical static and fatigue strength of three newly designed plates with gold standard plates for the treatment of medial knee joint osteoarthritis. Methods: Sixteen fourth-generation tibial bone composites underwent a medial open-wedge high tibial osteotomyn(HTO) according to standard techniques, using five TomoFix standard plates, five PEEKPower plates and six iBalance implants. Static compression load to failure and load-controlled cyclic fatigue failure tests were performed. Forces, horizontal and vertical displacements were measured; rotational permanent plastic deformations, maximal displacement ranges in the hysteresis loops of the cyclic loading responses and dynamic stiffness were determined. Results: Static compression load to failure tests revealed that all plates showed sufficient stability up to 2400 N without any signs of opposite cortex fracture, which occurred above this load in all constructs at different load levels. During the fatigue failure tests, screw breakage in the iBalance group and opposite cortex fractures in all constructs occurred only under physiological loading conditions (<2400 N). The highest fatigue strength in terms of maximal load and number of cycles performed prior to failure was observed for the ContourLock group followed by the iBalance implants, the TomoFix standard (std) and small stature (sm) plates. The PEEKPower group showed the lowest fatigue strength. Conclusions: All plates showed sufficient stability under static loading. Compared to the TomoFix and the PEEKPower plates, the ContourLock plate and iBalance implant showed a higher mechanical fatigue strength during cyclic fatigue testing. These data suggest that both mechanical static and fatigue strength increase with a wider proximal T-shaped plate design together with diverging proximal screws as used in the ContourLock plate or a closed-wedge construction as in the iBalance design. Mechanical strength of the bone-implant constructs decreases with a narrow T-shaped proximal end design and converging proximal screws (TomoFix) or a short vertical plate design (PEEKPower Plate). Whenever high mechanical strength is required, a ContourLock or iBalance plate should be selected. [less ▲]

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