TY - JOUR A1 - Jiang, C. A1 - Xie, G. A1 - Wu, Dejian A1 - Yan, T. A1 - Chen, S. A1 - Zhao, P. A1 - Wu, Z. A1 - Li, W. T1 - Experimental investigation on an energy-efficient floor heating system with intelligent control: A case study in Chengdu, China N2 - The space heating system accounts for 20%~50% of building energy consumption, and may lead to energy waste due to unreasonable controls. In this study, an energy-efficient floor heating system with intelligent control was proposed to improve energy efficiency of the system. In order to validate the concept of the proposed intelligent control, an experimental system was designed and constructed in Chengdu, China. Temperature, control cycle and energy consumption were then studied under different control strategies. The result shows that a larger flow rate of supply water will result in a longer control cycle and a lower control frequency, i.e., the average control cycle at 7 L min−1 is 1.7 h during the test day, while it is 1.5 h at 5 L min−1. Moreover, adopting water with a higher temperature and flow rate could achieve a higher efficiency of the system. The energy consumptions in case 1 (5 L min−1, 50 °C), case 2 (5 L min−1, 55 °C), case 5 (7 L min−1, 55 °C) and case 6 (7 L min−1, 60 °C) are 4746 kJ, 3534 kJ, 3093 kJ and 3028 kJ, respectively. Based on the experimental data, the supply water temperature is suggested to set lower than 60 °C considering human comfort. KW - Floor heating KW - Intelligent control KW - Experimental KW - Energy consumption KW - Control strategy PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550522 DO - https://doi.org/10.1016/j.csite.2021.101094 SN - 2214-157X VL - 26 SP - 1 EP - 14 PB - Elsevier Ltd. AN - OPUS4-55052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bachmann, Marcel A1 - Carstensen, J. A1 - Bergmann, L. A1 - dos Santos, J. F. A1 - Wu, C. S. A1 - Rethmeier, Michael T1 - Numerical simulation of thermally induced residual stresses in friction stir welding of aluminum alloy 2024-T3 at different welding speeds N2 - The paper deals with a numerical finite element simulation of the residual stress evolution in friction stir welding of 6 mm thick aluminum alloy AA2024-T3. The transient thermal field during the welding process was calculated with the commercial code COMSOL Multiphysics 5.0. Therefore, a thermal-pseudo-mechanical (TPM) heat source was implemented. A subsequent mechanical simulation was performed with varying hardening models for different welding speeds of 60 and 300 mm/min. The influence of softening of the material, which was due to hardening precipitation dissolution associated to the heating, was also investigated. Experiments in terms of thermocouple measurements as well as Vickers hardness and X-ray measurements of the residual stresses were conducted and compared to numerically obtained results. A qualitatively as well as quantitatively good agreement was found for different applied welding speeds. KW - Friction stir welding KW - Residual stress KW - Finite element simulation KW - Thermal softening KW - Aluminum alloy 2024-T3 PY - 2017 DO - https://doi.org/10.1007/s00170-016-9793-8 SN - 0268-3768 SN - 1433-3015 VL - 91 SP - 1443 EP - 1452 PB - Springer CY - London AN - OPUS4-40511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, X. A1 - Shi, L. A1 - Wu, C. A1 - Yang, Chunliang A1 - Gao, S. T1 - Multi-phase modelling of heat and mass transfer during Ti/Al dissimilar friction stir welding process N2 - Friction stir welding (FSW) has the capacity to join the Al/Ti dissimilar structures with superior mechanical properties. The microstructures and mechanical characteristics of Al/Ti dissimilar FSW joints are determined by the heat and mass transfer during the welding process. However, a quantitative study of the Al/Ti dissimilar FSW process is lacking. Therefore, using the computational fluid dynamics (CFD) and volume of fluid (VOF) approach, a multi-phase model was constructed for quantitatively analyzing the heat and mass transfer behaviour in dissimilar FSW of TC4 titanium alloy and AA2024-T4 aluminium alloy. The mixed material was treated as a functionally graded material (FGM) to compute the thermophysical characteristics at the weld nugget zone (WNZ). Due to the vast disparity in the thermophysical characteristics of aluminum and titanium alloy, the temperature field in Al/Ti dissimilar FSW was severely asymmetric. The temperature of titanium alloy on the advancing side (AS) was higher than that of aluminium alloy on the retreating side (RS) at the same distance from the tool centre line near the tool shoulder, but it was lower than that of aluminium alloy on the RS without the influence of the shoulder. Due to the high flow stress of titanium alloy, plastic material flow mostly occurred on the RS of aluminium alloy in the Al/Ti dissimilar FSW, with its percentage exceeding 80%. This model was validated by experiment results. KW - Dissimilar friction stir welding KW - Al/Ti dissimilar joints KW - Temperature distribution KW - Heat generation KW - Plastic material flow PY - 2023 DO - https://doi.org/10.1016/j.jmapro.2023.03.037 SN - 2212-4616 VL - 94 SP - 240 EP - 254 PB - Elsevier Ltd. AN - OPUS4-57265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Noble, J.E. A1 - Wang, L. A1 - Cerasoli, E. A1 - Knight, A.E. A1 - Porter, R.A. A1 - Gray, E. A1 - Howe, C. A1 - Hannes, E. A1 - Corbisier, P. A1 - Wang, J. A1 - Wu, L. A1 - Altieri, I. A1 - Patriarca, M. A1 - Hoffmann, Angelika A1 - Resch-Genger, Ute A1 - Ebert, B. A1 - Voigt, Jan A1 - Shigeri, Y. A1 - Vonsky, M.S. A1 - Konopelko, L.A. A1 - Gaigalas, A.K. A1 - Bailey, M. J. A. T1 - An international comparability study to determine the sources of uncertainty associated with a non-competitive sandwich fluorescent ELISA KW - ELISA KW - Fluorescence KW - Interferon KW - Uncertainty KW - Round Robin KW - Immunoassay KW - Quality assurance KW - Fluorescein PY - 2008 SN - 1434-6621 SN - 1437-8523 VL - 46 IS - 7 SP - 1033 EP - 1045 PB - De Gruyter CY - Berlin AN - OPUS4-18283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -