| 1. |
- Yuan, Ye, et al.
(författare)
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Smart Pavement: An Attention-Based Classification Model for Road Pavement Material
- 2022
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Ingår i: Smart Innovation, Systems and Technologies. - Singapore : Springer Nature Singapore. - 2190-3026 .- 2190-3018. ; 304 SIST, s. 133-140
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Konferensbidrag (refereegranskat)abstract
- Intelligent recognition of traffic road damage is essential for realizing smart vehicles and intelligent transportation systems. The classification of road material types before recognition is a challenge for traffic road damage recognition due to differences in features such as concrete and asphalt. In addition, the widely distributed roads make environmental factors a critical factor affecting the classification. In this paper, we propose a deep learning-based road material classification method that introduces an attention mechanism to deal with the influence of different environments on road material recognition. We acquired tens of thousands of road surface images for training and testing and performed practical validation in real roads. The experiments show that our method has high accuracy and recall in road material classification.
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| 2. |
- Li, Xue-Yuan, et al.
(författare)
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Combination of modern plant breeding and enzyme technology to obtain highly enriched erucic acid from Crambe oil
- 2016
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Ingår i: Sustainable Chemical Processes. - : Springer Science and Business Media LLC. - 2043-7129. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Background Fatty acids from vegetable oils are useful building blocks for industrial materials. The purpose of this work was to prepare erucic acid with high purity from a vegetable oil. High purity erucic acid is used for the production of erucamide with applications in plastics manufacturing. A newly developed transgenic Crambe line produces seed oil with 68% erucic acid compared to 53% in the wild type oil. Results Further enrichment of erucic acid from Crambe (wild type and transgenic) oil was achieved by selective enzymatic hydrolysis. UsingCandida rugosalipase as catalyst, other fatty acids were preferentially hydrolysed from the triacylglycerols and erucic acid was enriched in the acylglycerol fraction. The highest content of erucic acid achieved in that fraction was 95%. Conclusions The combination of modern plant breeding and enzyme technology is a promising approach for preparation of fatty acids of high purity.
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| 3. |
- Liu, Yanrong, et al.
(författare)
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Ionic liquids as a new cornerstone to support hydrogen energy
- 2023
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Ingår i: Green Chemistry. - : Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 25:13, s. 4981-4994
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Forskningsöversikt (refereegranskat)abstract
- As a fuel or energy carrier, hydrogen has been identified as a key way to decarbonize electricity, industry, transportation, and heating sectors. Hydrogen can be produced by a variety of methods, among which water electrolysis driven by renewable energy is sustainable and nearly carbon-free. To use hydrogen widely, storage and transportation over long distances are another key issue. Apart from storage at high pressure and low temperature, hydrogen can be stored in organic compounds via chemical bonding under relatively mild conditions. Efficient utilization of hydrogen includes hydrogen fuel cells as an alternative to internal combustion engines. From the above scenarios, catalysis and reaction media are the key factors for realizing hydrogen energy implementation. Ionic liquids (ILs) offer new opportunities due to their tunable functional groups, low vapor pressure, and stable structures as additives, solvents, and charge transfer materials. ILs are known to produce solid catalysts with controllable properties, decorate solid catalysts with modified electrons and geometric structures, and serve as electrolytes and hydrogen storage media. This review summarizes and recaps the recent progress in how ILs act as a cornerstone to support the production, storage, and utilization of hydrogen. Furthermore, critical challenges and future research directions of ILs in hydrogen energy applications are also outlined.
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| 4. |
- Deng, Na, et al.
(författare)
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Comparative analysis of optimal operation strategies for district heating and cooling system based on design and actual load
- 2017
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 205, s. 577-588
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Tidskriftsartikel (refereegranskat)abstract
- Computational load significantly influences energy and cost savings when developing an operation strategy for a district heating and cooling system. In this study, a model was identified to study the effects of the difference between design load and actual load on an optimal operation strategy. The established model is strongly dependent on the economy principle, and the proposed optimal strategy could achieve a dynamic balance between the users' load and the system energy supply. This model was validated at 30% load rate, which demonstrated an obvious cost saving of 63.6% under the actual load and 42.2% under the design load. Based on the current strategy, the optimal strategy at different load rates was analyzed with respect to two characteristics of each subsystem: energy outputs and operation costs. Furthermore, in the optimal strategy, changes in total operation costs and cost savings rates under different load rates are also discussed. The results showed that, when the load rate was changed from 30 to 75%, the savings rates based on the design load were 42.2, 17.9, 2.5, and 12.6%, and the savings rates based on the actual load were 63.6, 49.8, 34.3, and 25.7%, respectively. Based on the actual load, the energy savings advantage of the optimal operation strategy could be maximized, in particular, during the initial stage of project construction. Furthermore, the commercial software MATLAB was used for programming and calculations. The simulation results indicated that the application of the combined cooling, heating, and power system could significantly improve the cost-effectiveness.
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| 5. |
- Han, Xin-Bao, et al.
(författare)
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Fe-substituted cobalt-phosphate polyoxometalates as enhanced oxygen evolution catalysts in acidic media
- 2020
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Ingår i: Cuihuà xuébào. - : Science Press. - 0253-9837 .- 1872-2067. ; 41:5, s. 853-857
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Tidskriftsartikel (refereegranskat)abstract
- All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance. However, their atomically precise structures remain undefined, complicating their optimization and limiting the understanding of their enhanced performance. Here, the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{Co-4(OH)(3)(PO4)}(4)(SiW9O34)(4)](32-) (1), which may serve as a molecular model of multimetal hydr(oxy)oxides. The catalytic activity is enhanced upon replacing Co by Fe in 1, resulting in a reduced overpotential (385 mV) for oxygen evolution (by 66 mV) compared to that of the parent 1 at 10 mA cm(-2) in an acidic medium; this overpotential is comparable to that for the IrO2 catalyst. These abundant-metal-based polyoxometalates exhibit high stability, with no evidence of degradation even after 24 h of operation.
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| 6. |
- Huo, Jingwen, et al.
(författare)
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Drivers of fluctuating embodied carbon emissions in international services trade
- 2021
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Ingår i: One Earth. - : ELSEVIER. - 2590-3330 .- 2590-3322. ; 4:9, s. 1322-1332
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Tidskriftsartikel (refereegranskat)abstract
- Service industries are generally considered "green'' because of their marginal direct emissions; however, they account for 65% of the world gross domestic product and over 20% of total global trade in 2019. Here, we quantify the evolution of carbon emissions embodied in services trade from 2010 to 2018 and identify the driving factors of emission change at the global and regional scales. The annual growth rate of embodied emissions exported from the Global South (2.0%) is double that of the Global North (1.0%), with a different trade structure. We further identify three trade patterns of service export in the Global South based on the bilateral trade partnership and annual growth rate. Three kinds of specific emission mitigation policies are proposed based on the characters of services trade and different trade structures between different regions. The results provide quantitative evidence currently lacking and critical to policy decision making.
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| 7. |
- Jia, Xue, et al.
(författare)
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CsPb(IxBr1-x)(3) solar cells
- 2019
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Ingår i: Science Bulletin. - : ELSEVIER. - 2095-9273. ; 64:20, s. 1532-1539
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Tidskriftsartikel (refereegranskat)abstract
- Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell (PSC) becomes a promising candidate for next-generation high-efficiency solar cells. The power conversion efficiency (PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)(3) and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)(3) solar cells and outline possible directions to further improve the device performance. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.
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| 8. |
- Qian, Jin Yuan, et al.
(författare)
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A geometric study on shell side heat transfer and flow resistance of a six-start spirally corrugated tube
- 2018
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Ingår i: Numerical Heat Transfer; Part A: Applications. - : Informa UK Limited. - 1040-7782 .- 1521-0634. ; 73:8, s. 565-582
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Tidskriftsartikel (refereegranskat)abstract
- Heat transfer enhancement is of great importance for energy efficiency improvement. The utilization of spirally corrugated tubes is one of the efficient ways to strengthen heat transfer. In this article, based on a validated numerical model, the effects of geometric parameters of a six-start spirally corrugated tube, including the pitch p and the corrugation depth e, on the shell side heat transfer and flow resistance performance are numerically investigated, in high Reynolds number conditions ranging from 10,000 to 60,000. The shell side secondary flow velocity distribution, longitudinal vortex distribution, and temperature distribution of a six-start spirally corrugated tube are presented, respectively. In addition, the heat transfer and flow resistance characteristics are evaluated by comparing the Nusselt number and the flow resistance coefficient with these of smooth tubes. Results show that the utilization of six-start spirally corrugated tubes can enhance the heat transfer performance at the expense of an increase of the flow resistance. However, with the same geometric parameters, the Nusselt number increases and the flow resistance coefficient decreases as Reynolds number increases. With the pitch increasing, the Nusselt number and the flow resistance coefficient decrease at a fixed Reynolds number. In contrast, as the corrugation depth increasing, the Nusselt number changes irregularly, and the flow resistance coefficient increases. Finally, correlations for the shell side Nusselt number and flow resistance coefficient of the six-start spirally corrugated tube are established. This work is of significance for engineers and scientists focusing on the heat transfer and the flow resistance characteristics of spirally corrugated tubes and their applications.
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| 9. |
- Qian, Jin yuan, et al.
(författare)
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Analysis of Fouling in Six-Start Spirally Corrugated Tubes
- 2020
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Ingår i: Heat Transfer Engineering. - : Informa UK Limited. - 0145-7632 .- 1521-0537. ; 41, s. 1885-1900
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Tidskriftsartikel (refereegranskat)abstract
- Fouling on heat exchanger surfaces can weaken the heat-transfer capability, increase the energy consumption, and even cause the failure of the whole system. In coaxial heat exchangers, spirally corrugated tubes perform better than smooth ones concerning heat transfer and antifouling. In this article, a parametric study on the antifouling performance of a six-start spirally corrugated tube is carried out with a solid–liquid two-phase model. First, comparisons between a smooth tube and a specific sample six-start spirally corrugated tube on the solid particle volume fraction distributions are carried out. Then, the effects of solid particle diameter, the main geometric parameters, including pitch and the corrugation depth, are investigated. Analyzing the solid particle volume fraction with different geometries, solid particle diameters and Reynolds number, the roles played by the centrifugal force, drag force, and gravity of solid particles on fouling performance in six-start spirally corrugated tubes are obtained. In addition, the corrugation depth affects the volume fraction range more while the pitch affects more on the steady range of particle volume fraction. This work is of significance for further design of spirally corrugated tubes and analysis of fouling problems in heat exchangers.
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| 10. |
- Shao, Xue-Feng, et al.
(författare)
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Polyvinylpyrrolidone (PVP)-enabled significant suppression of supercooling of erythritol for medium-temperature thermal energy storage
- 2022
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Ingår i: Journal of Energy Storage. - : Elsevier BV. - 2352-152X .- 2352-1538. ; 46, s. 103915-
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Tidskriftsartikel (refereegranskat)abstract
- The supercooling effect is deemed to be a crucial issue for thermal energy storage using phase change materials (PCMs). The exploration of promising additives plays a decisive role in effective suppression efforts for suppressing the supercooling effect of a PCM. The present work proposed a potential additive, polyvinylpyrrolidone (PVP), to reduce the supercooling of erythritol, which is the most promising polyol PCM candidate for medium temperature range. PVP with various loadings was dispersed in erythritol to make composites for the proof-of-concept tests. It was shown that the degree of supercooling of erythritol can be reduced significantly from over 64 ? to about 21 ? in the presence of only 1.0 wt.% PVP. Along with the mitigated supercooling effect, the addition of PVP also leads to an increase of the retrievable latent heat during crystallization, from ~187 J/g to ~224 J/g at the same minute PVP loading of 1.0 wt.%, by increasing the crystallinity of erythritol. The PVP-loaded erythritol composites exhibit little sacrifice in latent heat of fusion, i.e., only ~15% loss when the PVP loading reaches 6.0 wt.%. In addition, multiple tests confirmed that PVP can be dissolved in erythritol, thus desirable compatibility was obtained and the composites would have long-term reliability. This proposed additive enables an efficient and cost-effective way for improving the crystallization behaviors of erythritol (and other polyol PCMs) towards real-world applications.
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