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 JF - Case Studies in Thermal Engineering 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 - Wu, Z. A1 - Guo, X. A1 - Xie, G. A1 - Yan, T. A1 - Wu, Dejian A1 - Zhang, F. A1 - Ang, R. T1 - Heat and electric flux coupling of closed-loop thermoelectric generator JF - Energy Conversion and Management N2 - Thermoelectric generator (TEG) has been proved as a promising technology for directly converting heat into electricity based on Seebeck effect. On the contrary, this electricity can trigger a solid-state cooling based on conventional Peltier effect. However, these two effects induce a coupling between heat and electric flux, especially for the quantitative relationship still remaining a mystery. Here, we show experimental evidence and theoretical calculation for the coupling by monitoring transient response of fluid temperature and output power. The experimental maximum heat flow in open circuit is 1162 W at cold fluid flow rate = 0.3 m3/h and fluid temperature difference ΔTf = 70 °C, enhanced by 13% owing to heat compensation from intrinsic coupling in closed-loop circuit. Meanwhile, the measured maximum output power of TEG is 18.2 W, and subsequently decreases to 15.4 W due to the objective existence of coupling. This double-edged sword in coupling vigorously inspires the potential applications in heat-dissipation situation such as spacecraft, electronic components, photovoltaic, refrigerator and etc. Present findings open a novel avenue for manipulating heat-electricity conversion in practical engineering. KW - Thermoelectric generator PY - 2021 DO - https://doi.org/10.1016/j.enconman.2021.114529 SN - 0196-8904 VL - 244 SP - 1 EP - 13 PB - Elsevier Ltd. AN - OPUS4-53661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xu, H.-J. A1 - Mack, J. A1 - Wu, D. A1 - Xue, Z.-L. A1 - Descalzo López, Ana Belén A1 - Rurack, Knut A1 - Kobayashi, N. A1 - Shen, Z. T1 - Synthesis and properties of fused-ring-expanded porphyrins that were core-modified with group 16 heteroatoms JF - Chemistry - A European journal N2 - The synthesis of a series of novel core-modified and fused-ring-expanded tetraphenylporphyrins is reported. Theoretical calculations and magnetic circular dichroism (MCD) and fluorescence spectroscopic measurements were used to analyze the effect of core modification with Group 16 oxygen, sulfur, selenium, and tellurium atoms on the optical properties and electronic structures of the porphyrins. Marked redshifts of the Q and B bands and accelerated intersystem-crossing rates were observed, thus making these compounds potentially suitable for use in a variety of applications. The scope for further fine-tuning of these optical properties based on additional structural modifications, such as the incorporation of fused benzene rings to form ABAB structures by using a thiophene precursor with a fused bicyclo[2.2.2]octadiene ring and the introduction of various substituents onto the meso-phenyl rings, is also examined. KW - Density functional calculations KW - Fluorescence KW - MCD spectroscopy KW - Porphyrinoids KW - Ring expansion PY - 2012 DO - https://doi.org/10.1002/chem.201200956 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 52 SP - 16844 EP - 16867 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, D. A1 - Descalzo López, Ana Belén A1 - Weik, F. A1 - Emmerling, Franziska A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - Ein kernmodifiziertes Rubyrin mit meso-Aryl-Subsituenten und Phenanthren-anellierten Pyrrolringen als hoch konjugierter NIR-Farbstoff und Hg2+-Sonde JF - Angewandte Chemie KW - Fluoreszenz KW - NIR-Farbstoffe KW - Porphyrinoide KW - Quecksilber KW - Sensoren PY - 2008 DO - https://doi.org/10.1002/ange.200702854 SN - 0044-8249 SN - 0932-2140 SN - 1521-3757 VL - 120 IS - 1 SP - 199 EP - 203 PB - Wiley-VCH CY - Weinheim AN - OPUS4-16447 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, D. A1 - Descalzo López, Ana Belén A1 - Weik, F. A1 - Emmerling, Franziska A1 - Shen, Z. A1 - You, X.-Z. A1 - Rurack, Knut T1 - A core-modified Rubyrin with meso-aryl substituents and phenanthrene-fused pyrrole rings: a highly conjugated near-infrared dye and Hg2+ probe JF - Angewandte Chemie / International Edition KW - Fluorescence KW - Mercury KW - NIR dyes KW - Porphyrinoids KW - Sensors PY - 2008 DO - https://doi.org/10.1002/Anie.200702854 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 47 IS - 1 SP - 193 EP - 197 PB - Wiley-VCH CY - Weinheim AN - OPUS4-16448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, Dejian A1 - Zhu, Z. A1 - Bao, Z. T1 - Optimization of the content distribution of expanded natural graphite in a multilayer metal hydride bed for thermochemical heat storage JF - Applied Thermal Engineering N2 - The poor thermal conductivity of MH beds limits hydrogen absorption in metal hydride (MH) reactors for thermochemical heat storage. The compaction of MH powder with expanded natural graphite (ENG) is an efficient and cost-effective approach for the heat transfer enhancement of MH beds. However, the addition of ENG reduces the hydrogen storage density of the compacted composites. How to optimize the allocation of a limited amount of ENG in the MH bed has not been studied. In this study, a multilayer MH bed configuration with an ENG grade content was adopted to improve the heat transfer performance of an MH reactor for thermochemical heat storage. The effect of the ENG content gradient on the performance of the MH reactor was investigated using a mathematical model of the MH reactor. Furthermore, an optimization method based on the entransy dissipation extremum principle (EDEP) was proposed to optimize the ENG distribution in magnesium hydride (MgH2)-ENG compacts. The results showed that a larger ENG content gradient resulted in faster hydrogen absorption and better heat-discharge performance. Compared with a configuration with a uniform ENG content, the optimized configuration based on the EDEP exhibited a shorter reaction time, more uniform bed temperature distribution, and 15.33% higher gravimetric exergy-output rate. In addition, the number of optimization iterations had little effect on the optimal results, which could be obtained by implementing only one optimization iteration. The optimization results showed that more ENG should be allocated to the internal layer of the MgH2-ENG compact. The compacts were divided into three layers, and the ENG content of each layer was calculated according to the optimized configuration based on the EDEP. The optimization method proposed in this study can be applied to optimize KW - Metal hydride reactor KW - Expanded natural graphite KW - Multilayer bed KW - Entransy dissipation exremum principle KW - Thermochemical heat storage PY - 2022 DO - https://doi.org/10.1016/j.applthermaleng.2022.119115 SN - 1359-4311 VL - 216 SP - 1 EP - 10 PB - Elsevier Ltd. AN - OPUS4-55890 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fokong, S. A1 - Theek, B. A1 - Wu, Z. A1 - Koczera, P. A1 - Appold, L. A1 - Jorge, S. A1 - Resch-Genger, Ute A1 - van Zandvoort, M. A1 - Storm, G. A1 - Kiessling, F. A1 - Lammers, T. T1 - Image-guided, targeted and triggered drug delivery to tumors using polymer-based microbubbles JF - Journal of controlled release N2 - Microbubbles (MB) are routinely used contrast agents for functional and molecular ultrasound (US) imaging. In addition, they have been attracting more and more attention for drug delivery purposes, enabling e.g. US-mediated drug delivery across biological barriers and US-induced triggered drug release from the MB shell. The vast majority of efforts in this regard have thus far focused on phospholipid-based soft-shell MB, which are suboptimal for stably incorporating large amounts of drug molecules because of their relatively thin shell. Using poly(butyl cyanoacrylate) (PBCA)-based hard-shell MB, we show here that both hydrophilic (Rhodamine-B) and hydrophobic (Coumarin-6) model drugs can be efficiently and stably entrapped within the ~ 50 nm shell of PBCA MB. In addition, we demonstrate that model drug loading does not negatively affect the acoustic properties of the MB, and that functionalizing the surface of fluorophore-loaded MB with anti-VEGFR2 antibodies enables image-guided and targeted model drug delivery to tumor blood vessels. Finally, we show both in vitro and in vivo that disintegrating VEGFR2-targeted MB with high-mechanical index US pulses leads to high levels of model drug release. Consequently, these findings indicate that polymer-based MB are highly suitable systems for image-guided, targeted and triggered drug delivery to tumors and tumor blood vessels. KW - Ultrasound KW - Microbubbles KW - Fluorescent reporter KW - Drug delivery KW - Tumor targeting KW - Theranostics PY - 2012 DO - https://doi.org/10.1016/j.jconrel.2012.05.007 SN - 0168-3659 SN - 1873-4995 VL - 163 IS - 1 SP - 75 EP - 81 PB - Elsevier CY - Amsterdam AN - OPUS4-27591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Song, Z. A1 - He, T. A1 - Li, M. A1 - Wu, Dejian A1 - You, F. T1 - Self-sustaining smoldering as a novel disposal approach for food waste with high moisture content JF - Fuel Processing Technology N2 - This work aims to explore the self-sustaining smoldering treatment (SSST) for the destruction of food waste. The food waste used in this work mainly consists of cereal, vegetable, and meat. To examine the processing procedures and parameters, three experimental groups (raw food waste, food-waste paste and food-waste paste blended with anthracite) and five variables (moisture content, sand size, sand-to-food waste ratio, air flow and food waste-to-coal ratio) were extensively investigated. Results show that raw food waste with 40% moisture content can be disposed by SSST with the mass destruction ratio over 90%. However, the robustness of SSST for raw food waste is constrained by the heterogeneous issue due to a variety of components and sizes of food waste. This issue is addressed through stir pre-processing of raw food waste as food-waste paste. The robustness of SSST for food waste is significantly further enhanced only if a slight mass fraction of anthracite (<20% of raw food waste) is supplemented. This provides an alternative solution for employing SSST for raw food waste with very high moisture content. KW - Food waste KW - Waste disposal KW - Smoldering combustion KW - Self-sustaining propagation PY - 2021 DO - https://doi.org/10.1016/j.fuproc.2021.107144 SN - 0078-3820 VL - 228 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-55053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, D. A1 - Ji, T. A1 - Jing, Q. A1 - He, W. A1 - Fan, Z. A1 - Wu, Dejian A1 - Qian, X. T1 - Experimental study and mechanism model on the ignition sensitivity of typical organic dust clouds in O2/N2, O2/Ar and O2/CO2 atmospheres JF - Journal of Hazardous Materials N2 - To reveal and improve our understanding of the ignition behavior and mechanism, G-G furnace experiments of three typical organic dusts were performed to investigate the minimum ignition temperature (MIT) in O2/N2, O2/ Ar and O2/CO2 atmospheres with oxygen mole fraction from 8.4% to 50%. The experimental results were presented in oxygen-lean and oxy-fuel atmospheres to evaluate the ignition sensitivity of dusts in different atmospheres. It was found that CO2 is the strongest in terms of lowing the ignition sensitivity of the three dusts, and the dust explosion risk increases significantly with increasing O2 mole fraction for the three dusts through a logarithmically and significantly reducing MIT. However, for different dusts, inert gases show different suppression effects. In addition, a modified steady-state homogeneous ignition model was proposed and successfully applied to oxygen-lean atmospheres, and in oxy-fuel atmospheres, this model has also been improved to estimate the ignition mechanism. This ignition mechanism model could be used to successfully predict the minimum ignition temperature of high volatile dust under different inert atmospheres controlled by homogeneous ignition, which will provide a reference for the ignition hazard assessment of dust on hot surfaces. KW - Dust explosions KW - Gas explosions KW - Minimum ignition temperature KW - Hybrid mixtures PY - 2021 DO - https://doi.org/10.1016/j.jhazmat.2021.125108 SN - 0304-3894 VL - 412 SP - 125108 PB - Elsevier B.V. AN - OPUS4-53660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tang, F A1 - Wu, Z A1 - Yang, C A1 - Osenberg, M A1 - Hilger, A A1 - Dong, K A1 - Markötter, Henning A1 - Manke, I A1 - Sun, F A1 - Chen, L A1 - Cui, G T1 - Synchrotron X-ray tomography for rechargeable battery research: Fundamentals, setups and applications JF - Small Methods N2 - Understanding the complicated interplay of the continuously evolving electrode materials in their inherent 3D states during the battery operating condition is of great importance for advancing rechargeable battery research. In this regard, the synchrotron X-ray tomography technique, which enables non-destructive, multi-scale, and 3D imaging of a variety of electrode components before/during/after battery operation, becomes an essential tool to deepen this understanding. The past few years have witnessed an increasingly growing interest in applying this technique in battery research. Hence, it is time to not only summarize the already obtained battery-related Knowledge by using this technique, but also to present a fundamental elucidation of this technique to boost future studies in battery research. To this end, this review firstly introduces the fundamental principles and experimental Setups of the synchrotron X-ray tomography technique. After that, a user guide to ist application in battery research and examples of its applications in Research of various types of batteries are presented. The current review ends with a discussion of the future opportunities of this technique for next-generation rechargeable batteries research. It is expected that this review can enhance the reader’s understanding of the synchrotron X-ray tomography technique and stimulate new ideas and opportunities in battery research. KW - 3D imaging KW - Batteries KW - Synchrotron X-Ray KW - Tomography PY - 2021 DO - https://doi.org/10.1002/smtd.202100557 VL - 5 IS - 9 SP - 2100557 PB - Wiley-VCH AN - OPUS4-53394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qiu, Yan A1 - Yu, H. A1 - Gornushkin, Igor B. A1 - Li, J. A1 - Wu, Q. A1 - Zhang, Z. A1 - Li, X. T1 - Measurement of trace chromium on structural steel surface from a nuclear power plant using dual-pulse fiber-optic laser-induced breakdown spectroscopy JF - Applied surface science N2 - Remote and on-line measurement of chromium on structural steel surface in nuclear power plants is critical for protection against fluid accelerated corrosion. To improve the insufficient sensitivity of fiber-optic laser-induced breakdown spectroscopy toward trace element detection, a dual-pulse spectral enhancement system is set up. In an iron matrix, for the purpose of improving sensitivity of trace chromium analysis and reducing the self-absorption of iron, the effects of key parameters are investigated. The optimal values of the parameters are found to be: 450 ns inter-pulse delay, 700 ns gate delay, 30 mJ/6 mJ pulse energy ratio, and 19.8 mm lens-to-sample distance (corresponding to a 799 μm laser focused spot size). Compared to the single-pulse system, the shot number of dual-pulse ablation is limited for reducing surface damage. After the optimization of the dual-pulse system, the signal-to-noise ratio of the trace chromium emission line has been improved by 3.5 times in comparison with the single-pulse system, and the self-absorption coefficient of matrix iron has been significantly reduced with self-reversal eliminated. The number of detectable lines for trace elements has more than doubled thus increasing the input for spectral calibration without significantly increasing the ablation mass. Three calibration methods including internal standardization, partial least squares regression and random forest regression are employed to determine the chromium and manganese concentrations in standard samples of low alloy steel, and the limit of detection is respectively calculated as 36 and 515 ppm. The leave-one-out cross validation method is utilized to evaluate the accuracy of chromium quantification, and the concentration mapping of chromium is performed on the surface of a steel sample (16MND5) with a relative error of 0.02 wt.% KW - Fiber-optic laser-induced breakdown spectroscopy (FO-LIBS) KW - Dual-pulse KW - Parameter optimization KW - Spectral enhancement KW - Self-absorption coefficient KW - Concentration mapping PY - 2020 DO - https://doi.org/10.1016/j.apsusc.2020.147497 SN - 0169-4332 VL - 533 IS - 147497 SP - 1 EP - 29 PB - Elsevier CY - Amsterdam AN - OPUS4-51143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, Martin A1 - Wu, D. A1 - Song, Z. A1 - Zhang, Q. A1 - Qian, X. T1 - Theoretical and numerical study on ignition behaviour of coal dust layers on a hot surface with corrected kinetic parameters JF - Journal of Hazardous Materials N2 - Industrial fires and explosions initiating from self-ignition of combustible porous dust deposits represent a serious hazard for human beings, environment and industry. Understanding the fundamental basis of combustible dust ignition behaviours at different geometries is of importance to prevent and mitigate the accidental risks. A correlation of self-ignition temperatures (SITs) measured by hot-oven tests and minimum ignition temperatures of dust layers (MITLs) determined by hot-plate tests has been established previously. However, this analogy approach based on Frank-Kamenetzkii model is limited by ignoring the influence of oxygen diffusion. In this work, an improved method is developed by implementing a correction factor for the pre-exponential factor caused by the boundary geometry. This method is testified by comparing with experimental data, previous analogy method and numerical simulation. Results show that our proposed method performs a better predictability of MITLs and simplicity. The improved analogy method indicates that the different boundary geometries of a dust deposit significantly impact the apparent pre-exponential factor, while have an ignorable influence on the activation energy, which is also verified by numerical investigations. Furthermore, the numerical model with the corrected kinetic parameters provides a satisfactory explanation compared with experimental observations regarding to temperature and concentration evolutions of dust layers. KW - Spontanious ignition KW - Self-ignition KW - Minimum ignition temperature KW - Dust layers PY - 2019 DO - https://doi.org/10.1016/j.jhazmat.2019.01.032 VL - 368 SP - 156 EP - 162 PB - Elsevier AN - OPUS4-47854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -