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- Pecunia, Vincenzo, et al.
(author)
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Roadmap on energy harvesting materials
- 2023
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In: Journal of Physics. - : IOP Publishing. - 2515-7639. ; 6:4
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Journal article (peer-reviewed)abstract
- Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.
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| 2. |
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| 3. |
- Li, Fei, et al.
(author)
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Integration of FeOOH and Zeolitic Imidazolate Framework-Derived Nanoporous Carbon as an Efficient Electrocatalyst for Water Oxidation
- 2018
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In: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 8:10
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Journal article (peer-reviewed)abstract
- As a cost-effective catalyst for the oxygen evolution reaction (OER), the potential use of FeOOH is hindered by its intrinsic poor electron conductivity. Here, the significant enhancement of OER activity and long-term stability of electrodeposited FeOOH on zeolitic imidazolate framework-derived N-doped porous carbons (NPCs) are reported. In alkaline media, FeOOH/NPC supported on nickel foam as a 3D electrode delivers a current density of 100 mA cm(-2) at a small overpotential of 230 mV and exhibits a low Tafel slope of 33.8 mV dec(-1) as well as excellent durability, making it one of the most active OER catalysts. Such high performance is attributed to a combined effect of the excellent electron conductivity of NPC and the synergy between FeOOH and NiO derived from Ni substrate.
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| 4. |
- Murari, A., et al.
(author)
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A control oriented strategy of disruption prediction to avoid the configuration collapse of tokamak reactors
- 2024
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In: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
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Journal article (peer-reviewed)abstract
- The objective of thermonuclear fusion consists of producing electricity from the coalescence of light nuclei in high temperature plasmas. The most promising route to fusion envisages the confinement of such plasmas with magnetic fields, whose most studied configuration is the tokamak. Disruptions are catastrophic collapses affecting all tokamak devices and one of the main potential showstoppers on the route to a commercial reactor. In this work we report how, deploying innovative analysis methods on thousands of JET experiments covering the isotopic compositions from hydrogen to full tritium and including the major D-T campaign, the nature of the various forms of collapse is investigated in all phases of the discharges. An original approach to proximity detection has been developed, which allows determining both the probability of and the time interval remaining before an incoming disruption, with adaptive, from scratch, real time compatible techniques. The results indicate that physics based prediction and control tools can be developed, to deploy realistic strategies of disruption avoidance and prevention, meeting the requirements of the next generation of devices.
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| 7. |
- Zeng, Xiao, et al.
(author)
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A scoping study on remelting process of a debris bed in the lower head of reactor pressure vessel
- 2023
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In: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 189
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Journal article (peer-reviewed)abstract
- Coolability and retention of core melt (corium) in the lower head of reactor pressure vessel (RPV) has been accepted as a severe accident management strategy to maintain the reactor pressure vessel (RPV) integrity of a light water reactor. To qualify the in-vessel melt retention strategy, lots of studies have been performed to investigate the natural convection heat transfer of a melt pool in the lower head. However, little work has been attributed to the precursory phase of the melt pool, i.e., the remelting process of a debris bed which is formed in the lower head at the very beginning of corium relocation from the core the lower head. The present study is motivated to conduct an experimental study on the debris remelting process. For this purpose, a dedicated test facility named COREM (COrium REMelting) is conceived and constructed, which features internal heating of electromagnetic induction and visualization of debris remelting dynamics. The test section is a semicircular vessel representing a slice of scaled-down RPV lower head, whose front and back walls are made of transparent tempered glass which facilitate visualization and induction heating of the debris bed. Fiber probes with multiple optical temperature sensors are mounted in the semicircular wall of the test section to measure its temperature distribution. In the scoping test, n-octanol and Wood's metal are selected as the simulant materials of metallic and oxidic components of corium, respectively, and their particles ware loaded in the test section to form a debris bed. This paper presents the first two scoping tests which have been performed with the COREM facility so far, under different mixing ratios of two debris materials. The measured data include the photography of debris remelting processes and the temperatures in the debris bed and the semicircular wall. Based on the temperature distributions, heat flux profile along the semicircular vessel wall is also estimated. The scoping tests well reproduce the dynamic process of debris remelting, with two distinct stages of fusion of n-octanol and Wood's metal, i.e., melting successively from low to high melting-point debris particles. During the remelting process, the vessel wall temperatures increase with the polar angle firstly and then decrease gradually, leading to the highest temperature appearing in the middle of the lower layer of the stratified molten pool which is finally formed.
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| 8. |
- Li, Xin, et al.
(author)
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Intelligent fault diagnosis of bevel gearboxes using semi-supervised probability support matrix machine and infrared imaging
- 2023
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In: Reliability Engineering & System Safety. - : Elsevier. - 0951-8320 .- 1879-0836. ; 230
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Journal article (peer-reviewed)abstract
- Fault diagnosis is of great significance to ensure the reliability and safety of complex bevel gearbox systems. Most existing intelligent fault diagnosis approaches of bevel gearboxes are designed with vibration monitoring. However, the collected vibration data are vulnerable to noise pollution and machinery operating conditions. Besides, traditional fault diagnosis models highly rely on numerous labeled samples, and neglect the high cost of label annotation in real-world applications. Therefore, a novel fault diagnosis approach based on semi-supervised probability support matrix machine (SPSMM) and infrared imaging is proposed for bevel gearboxes in this paper, which has the following properties. Firstly, SPSMM classifies 2D matrix data directly without vectorization, thus fully utilizing the spatial information in infrared images. Secondly, a probability output strategy is designed for SPSMM to calculate the posterior class probability estimation of matrix inputs, and consequently enhance the diagnostic accuracy and robustness of the model. Thirdly, a semi-supervised learning (SSL) framework is proposed for SPSMM to carry out sample transfer from the unlabeled sample pool to the labeled sample pool, which can effectively alleviate the problem of insufficient labeled samples. The superiority of the proposed diagnosis approach is demonstrated with an infrared imaging dataset of a bevel gearbox.
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| 9. |
- Guo, Yong, et al.
(author)
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Deposition of droplets from the trachea or bronchus in the respiratory tract during exhalation : A steady-state numerical investigation
- 2020
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In: Aerosol Science and Technology. - : Informa UK Limited. - 0278-6826 .- 1521-7388. ; 54:8, s. 869-879
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Journal article (peer-reviewed)abstract
- Respiratory droplets are bioaerosols that originate from the respiratory tract. Knowing their deposition characteristics during exhalation would facilitate the understanding of the source of large respiratory droplets and their importance in the spread of respiratory infectious diseases. In this study, computational fluid dynamics is used to simulate the motion and deposition of droplets released from either trachea or bronchi in a realistic reconstruction of the human respiratory tract. Influences of airflow structures and locations of droplet generation on droplet deposition are studied, and droplets with diameters between 1 and 50 mu m are examined. The deposition of droplets is found to be influenced mainly by the droplet diameter and the flow rate of exhalation. The number of droplets released from the trachea or bronchi that can escape into the environment decreases as the flow rate increases. When the flow rate is low (10 L/min), the critical diameter of droplets generated in the lower respiratory system that can escape into the air is approximately 12 mu m, but this diameter is approximately 5 mu m when the flow rate is medium (30 to 60 L/min) or large (90 L/min). The larynx is the dominant site of deposition for droplets smaller than the critical diameter, while trachea and bronchus are more important locations that account for the deposition of larger droplets. This study indicates that the lower respiratory tract is an important source of fine droplets (<5 mu m) in indoor environments, and larger droplets probably originate from the upper respiratory tract, which needs further investigation. Copyright
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| 10. |
- Radamson, Henry H., et al.
(author)
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State of the Art and Future Perspectives in Advanced CMOS Technology
- 2020
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In: Nanomaterials. - : MDPI AG. - 2079-4991. ; 10:8
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Research review (peer-reviewed)abstract
- The international technology roadmap of semiconductors (ITRS) is approaching the historical end point and we observe that the semiconductor industry is driving complementary metal oxide semiconductor (CMOS) further towards unknown zones. Today's transistors with 3D structure and integrated advanced strain engineering differ radically from the original planar 2D ones due to the scaling down of the gate and source/drain regions according to Moore's law. This article presents a review of new architectures, simulation methods, and process technology for nano-scale transistors on the approach to the end of ITRS technology. The discussions cover innovative methods, challenges and difficulties in device processing, as well as new metrology techniques that may appear in the near future.
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