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4 records found

Journal article (2025) - M. Randall, M. B. Jensen, F. van de Ven, C. Zevenbergen, J. H. Körber, Z. Sun, S. Chen, S. Zhang
Urban stormwater is sometimes a risk, sometimes a resource. To address both aspects, the Three Points Approach (3PA) is advocated. This research applied the 3PA to map stormwater approaches in two Chinese and four European cities. While all cities have targets for the Technical Design Domain, none have targets for all domains; and thereby lack interventions to maximize benefits of frequent small events in the Day-to-Day Domain or minimize flood risks of rare large events in the Extreme Domain. Using open global precipitation data cities’ stormwater targets were expressed as more comparable rain depths, demonstrating that event depths within the Day-to-Day Domain in Chinese cities, cover much of the same range as those within the Technical Design Domain in the European cities. Expressing targets as depths in the context of the 3PA framework may facilitate transdisciplinary and transnational knowledge sharing, paving the way for management strategies covering all three domains. ...

Ultradense magnetic sources enable rapid diffuse field correlations

Journal article (2024) - G. Laloy-Borgna, B. Giammarinaro, Z. Sun, S. Catheline, J. Aichele
Perfectly diffuse wave fields are the underlying assumption for noise-correlation tomography in seismology, nondestructive testing, and elastography; however, perfectly diffuse fields are rarely encountered in real-world applications. We show that homogeneously distributed magnetic microparticles allow instantaneous generation of a diffuse wave field, which can be imaged using a clinical probe connected to a fully programmable ultrasound scanner. The particles are placed inside a bilayered hydrogel and act as elastic-wave sources on excitation by a magnetic pulse. Using ultrafast ultrasound imaging coupled to phase tracking, the diffuse elastic wave field is imaged. This allows the local wave velocity to be measured everywhere on the image using noise-correlation algorithms inspired by seismology. Thanks to this instantaneous diffuse wave field, a very short acquisition time is sufficient to retrieve the wave speed contrast of a bilayered phantom. The correlation time window can be shrunk down to three time samples, which we show in a numerical simulation mimicking the experimental conditions. Our experimental and numerical results are consistent with theoretical predictions made by information theory, and they pave the way for real-time elasticity imaging. This is of particular interest for monitoring of medical treatments through real-time tissue-elasticity assessment, and it is also applicable in related fields such as seismology and nondestructive testing. ...
Journal article (2017) - E. Haccuria, P. Ning, H. Cao, P. Venkatesan, W. Jin, Y. Yang, Z. Sun
The difficulties for selective metal recovery from electronic waste are induced by the high complexity of such waste stream and complicated purification procedures. In this research, an electrochemical stimulated method is demonstrated to selective recover copper from an industrially provided electronic waste. More specific, one-step selective copper recovery was achieved by combining electrochemical dissolution and deposition in ammonia-based electrolyte. In the process, copper instead of other impure metals from the electronic waste is selectively dissolved and electrochemically enhanced at the anode. On the other side of the cell, pure copper was electrodeposited at the cathode. The current efficiency was found to be significantly influenced by the applied current density if galvanostatic process was facilitated. Both temperature and copper concentration in the electrolyte were found to have positive effects on the current efficiency. In a well-controlled process, copper of 99.56 wt% purity can be obtained which can be further improved by preventing potential oxidation on the electrodeposited layer. This research provide a possibility for selective copper recovery in one-step by substantially decreasing the purification cost and simplifying copper recovery procedures from electronic waste. ...