| 1. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Gao, Xinyu, et al.
(author)
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Design and assessments on graded metal foam in heat storage tank : An experimental and numerical study
- 2023
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In: International Communications in Heat and Mass Transfer. - 0735-1933. ; 146
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Journal article (peer-reviewed)abstract
- The effectiveness of solidification in latent heat storage (LHS) systems has been restricted by the low thermal conductivity of pure phase change materials (PCMs). To address this challenge, an innovative composite PCM impregnated with metal foam has been introduced. This study investigates a vertical thermal energy storage (TES unit) filling with foamed copper with radial gradient pore density, with a focus on enhancing energy storage and heat conduction mixing through natural convection. Experiments and numerical models are employed to research the variation of liquid fraction, solid-liquid interfaces, temperature field, and velocity field, as well as to assess heat release properties, including thermal transfer distribution and heat release quantity. Results indicate a 14.3% reduction in solidification duration for both positive and negative radially graded pore density arrangements, compared to a homogeneous structure. In addition, temperature uniformity is improved by 4.0% in these two optimization structures, due to the influence of varied pore density. Findings from this work offer guidance for building more efficient latent energy storage tanks.
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| 3. |
- Gao, Xinyu, et al.
(author)
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Thermo-Economic Performance Analysis of Modified Latent Heat Storage System for Residential Heating
- 2023
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In: Energies. - 1996-1073. ; 16:19
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Journal article (peer-reviewed)abstract
- Solar energy is a sustainable source that can be effectively utilized to address winter heating challenges in buildings. To ensure the efficient application of solar energy for heating purposes and to maintain reliable performance of the heating system, the integration of phase-change materials (PCMs) in thermal energy storage (TES) systems has emerged as a crucial auxiliary approach. This study focuses on the design and simulation of four TES structures: smooth, finned, metallic foam, and metallic foam-finned tubes. It explores their thermal characteristics, such as complete melting time and heat flux, under various flow conditions. Additionally, a residential building in Xi’an is selected as the object, where the proposed solar energy phase-change TES system is employed to meet the heating demand. Economic indicators, including initial investment and investment payback period, are estimated using a static evaluation method. The results highlight that the complete melting time of the TES unit with a metallic foam-finned tube is 4800 s, which is 88.3% less than the smooth tube. Finally, based on the actual project, it is determined that the metallic foam-finned heating system, with an HTF flow rate of 0.25 m/s, requires the fewest TES devices (914) and has a payback period of 13 months.
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| 4. |
- Gao, Yiping, et al.
(author)
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A Multilevel Information Fusion-Based Deep Learning Method for Vision-Based Defect Recognition
- 2020
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In: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 69:7, s. 3980-3991
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Journal article (peer-reviewed)abstract
- Vision-based defect recognition is an important technology to guarantee quality in modern manufacturing systems. Deep learning (DL) becomes a research hotspot in vision-based defect recognition due to outstanding performances. However, most of the DL methods require a large sample to learn the defect information. While in some real-world cases, it is difficult and costly for data collecting, and only a small sample is available. Generally, a small sample contains less information, which may mislead the DL models so that they cannot work as expected. Therefore, this requirement impedes the wide applications of DL in vision-based defect recognition. To overcome this problem, this article proposes a multilevel information fusion-based DL method for vision-based defect recognition. In the proposed method, a three-level Gaussian pyramid is introduced to generate multilevel information of the defect so that more information is available for model training. After the Gaussian pyramid, three VGG16 networks are built to learn the information and the outputs are fused for the final recognition result. The experimental results show that the proposed method can extract more useful information and achieve better performances on small-sample tasks, compared with the conventional DL methods and defect recognition methods. Furthermore, the analysis results of the robustness and response time also indicate that the proposed method is robust for the noise input, and it is fast for defect recognition, which takes 13.74 ms to handle a defect image.
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| 5. |
- Hu, Rukun, et al.
(author)
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Design and assessment on a bottom-cut shape for latent heat storage tank filled with metal foam
- 2024
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In: International Journal of Thermal Sciences. - 1290-0729. ; 197
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Journal article (peer-reviewed)abstract
- The utilization of phase change materials (PCMs) holds tremendous potential of heat storage domain. The PCM's refractory at the latent heat thermal energy storage (LHTES) unit bottom hinders the heat storage efficiency, despite the significant improvement in thermal conductivity achieved through the addition of metal foam. This study employs numerical simulation to examine the impact of applying bottom cross-cut on PCM's spatial distribution in a horizontal LHTES unit. The manuscript analyzes parameters including melting fraction, complete melting time, Rayleigh number, natural convection heat transfer gain, melting phase interface, velocity and temperature distributions, and heat storage. The findings indicate that the proximity to the heating tube results in a reduction of solid volume at the LHTES unit bottom. A 0.6 bottom cross-cut ratio leads to an 18.84 % faster heat storage rate compared to a concentric-circle unit. Furthermore, a bottom cross-cut ratio of 0.5 enhances natural convection heat transfer gain by 3.28 times.
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| 6. |
- Huang, Xinyu, et al.
(author)
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Investigation and optimization on melting performance of a triplex-tube heat storage tank by rotational mechanism
- 2023
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In: International Journal of Heat and Mass Transfer. - : Elsevier BV. - 0017-9310. ; 205
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Journal article (peer-reviewed)abstract
- Phase change heat storage is the backbone of energy storage technology, but its storage time is affected by the low thermal conductivity of phase change materials. Therefore, the melting performance of a triplex-tube latent heat thermal energy storage unit (T-LHTESU) in a phase change heat storage system is studied in this paper, and the rotation mechanism is applied to the unit. Firstly, a numerical model of the T-LHTESU considering the rotation mechanism is constructed, and the validity of the rotation unit is verified by comparison with experimental data. In this unit, N-eicosane is used as a phase change material for heat exchange. The effects of different rotational speeds on the liquid phase distribution, temperature distribution, flow velocity distribution, total energy storage, and energy storage efficiency of the T-LHTESU are studied. The results show that the melting time of this unit at 0.1 and 1 rpm is 46.98 and 69.35% lower than that of the stationary model, respectively. The total amount of stored heat is decreased by 0.67 and 2.17%, and the heat storage efficiency is increased by 87.34% and 219.19%, respectively. This indicates that the addition of the rotation mechanism greatly increases the heat storage efficiency of the T-LHTESU and reduces its total melting time, while the reduction of the total energy stored in the melting cycle is small. Then it is proved that rotation improves the single heat transfer mechanism of the stationary model and eliminates the thermal deposition caused by natural convection by studying the internal temperature/velocity response of the stationary model and the speed of 0.1 rpm. The related geometric structure of the model is optimized by response surface optimization design based on 0.1 rpm rotation speed. The influence of each variable on the target response is obtained, and compared with the original model, the melting time of the optimized model is reduced by 12.24%. Finally, based on the geometric optimization design, the influence of element physical factors (temperature and material of fin/tube wall) on the related melting properties is studied. This study is helpful to promote the effective use of rotation mechanism in phase change heat storage systems and has a certain guiding role in the structural design.
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| 7. |
- Li, Yuanji, et al.
(author)
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Effect of pore density and filling ratio of metal foam on melting performance in a heat storage tank
- 2023
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In: Numerical Heat Transfer; Part A: Applications. - 1040-7782.
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Journal article (peer-reviewed)abstract
- Thermal energy storage through solid–liquid phase change is an efficient method for mitigating solar energy intermittency by providing continuous energy supply for the end-users. However, the low thermal conductivity of phase change material, which serves as the heat transfer medium in the thermal energy storage systems, severely undermines the heat charging/discharging rates. Metal foam can significantly strengthen the heat storage performance via increasing the thermal conduction capability of phase change material and metal foam composite, mainly due to the large extension surface area and highly-conducting metallic ligaments of the metal foam. To squarely explore the influence of the two vital parameters (filling ratio and pore density) for the metal foam upon the phase change process, numerical models for describing the phase change process in a tank filled with phase change material and metal foam are established, and the experimental validations of the corresponding models are performed. Melting time, temperature uniformity, and heat storage capacity are selected as the targeted indexes for assessing and evaluating the impacts of filling ratio and pore density on the phase change process. The results show that the full melting time of heat storage decreases first and then increases with the decrease of filling ratio under any PPI. The smaller the PPI, the smaller the overall heat storage time. And the larger the PPI, the greater effect of the filling ratio on the heat storage time. The melting time of the PCM under the optimal filling ratio of 10 PPI and 100 PPI is shortened by 8.06% and 18.06%, and the temperature uniformity is reduced by 5.48% and 10.11%, respectively, compared with that of the complete filling.
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| 8. |
- Peng, Kunkun, et al.
(author)
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A new joint data-model driven dynamic scheduling architecture for intelligent workshop
- 2019
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In: Proceedings of the ASME 14th International Manufacturing Science and Engineering Conference, 2019, vol 1. - : AMER SOC MECHANICAL ENGINEERS.
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Conference paper (peer-reviewed)abstract
- Intelligent manufacturing plays a significant role in Industry 4.0. Dynamic shop scheduling is a key problem and hot research topic in the intelligent manufacturing systems, which is NP-hard. However, traditional shop scheduling mode, dynamic event prediction approach, scheduling model and scheduling algorithm, cannot cope with increasingly complicated problems under kinds of scales production disruptions in the real-world production. To deal with these problems, this paper proposes a new joint data-model driven dynamic scheduling architecture for intelligent workshop. The architecture includes four new and key characteristics in the aspects of scheduling mode, dynamic event prediction, scheduling model and algorithm. More specifically, the new scheduling mode introduces data analytics methods to quickly and accurately deal with the dynamic events encountered in the production process. The new prediction model improves the deep learning method, and further applies it predict the dynamic events accurately to provide reliable input to the dynamic scheduling. The new scheduling model proposes a new hybrid rescheduling and inverse scheduling model, which can cope with almost scales of abnormal production problems. The new scheduling algorithm hybridizes dynamic programming and intelligent optimization algorithm, which can overcome the disadvantages of the two methods based on the analysis of solution space. The dynamic programming is employed to provide high-quality initial solutions for the intelligent optimization algorithm by reducing the computation time greatly. To sum up, the presented architecture is a new attempt to understand the problem domain knowledge and broaden the solving idea, which can also provide new theories and technologies to manufacturing system optimization and promote the applications of the theoretical results.
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| 9. |
- Cai, Weidong, et al.
(author)
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Multicolor light emission and multifunctional applications in double perovskite-Cs 2 NaInCl 6 by Cu + /Sb 3+co-doping
- 2024
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In: Chemical Engineering Journal. - : ELSEVIER SCIENCE SA. - 1385-8947 .- 1873-3212. ; 489
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Journal article (peer-reviewed)abstract
- Halide double perovskites managed by metal doping approach can exhibit dual emission colors, which have been considered as promising multicolor luminescent materials. However, an independent and stable emission at yellow region is missing owing to limited doping candidates, hindering the further commercialization of multicolor luminescence applications in double perovskites. In this work, we successfully obtain stable multicolor emission with PLQE (photoluminescence quantum yield) as high as 78% through developing the CuI doping strategy in Sb-Cs2NaInCl6. By introducing a high CuI feed ratio in airtight autoclave to compete the oxidization effect, the oxidization of CuI into CuII (detrimental factor for high PLQE due to serious quenching effect) is largely suppressed. With changing the CuI feed ratio, at least four distinct emission colors ranging from blue, purple, pink to yellow can be realized via changing the excitation wavelength. Depending on tunable multicolor emission, we further demonstrate the promise of our co-doped double perovskites in anti-counterfeiting technology and multicolor lighting devices. Our results open the way for enriching the optical applications of double perovskites based on multicolor emission.
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| 10. |
- Fan, Xiangyang, et al.
(author)
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Phosphine oxide modulator-ameliorated hole injection for blue perovskite light-emitting diodes
- 2023
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In: Journal of Materials Chemistry A. - : ROYAL SOC CHEMISTRY. - 2050-7488 .- 2050-7496. ; 11:38, s. 20808-20815
-
Journal article (peer-reviewed)abstract
- Despite the enormous developments in perovskite light-emitting diodes (PeLEDs) recently, obtaining efficient blue PeLEDs is still considered a critical challenge due to the non-radiative recombination and unbalanced charge injection caused by the unmatched carrier mobility and the deep hole-injection barrier between the hole-transport layer (HTL) and the emissive layer (EML). Herein, we incorporate tris(4-trifluoromethylphenyl)phosphine oxide (TMFPPO), obtained through a facile oxidation synthesis process, into poly(9-vinylcarbazole) (PVK). TMFPPO incorporation modulated the energy level and hole mobility of the binary-blend HTLs to eliminate the hole-injection barrier and balance the charge injection within the EML. Consequently, the blue PeLEDs with blended HTL presented an external quantum efficiency (EQE) of 7.23% centred at 477 nm, which was much higher than the EQE of a PVK device (4.95%). Our results demonstrate that modulating the energy level and charge injection of the HTL in the device is a promising method for obtaining efficient blue PeLEDs. TMFPPO is developed and incorporated into PVK to modulate the hole mobility and energy level of the hole-transport layer, giving rise to a barrier-free blue perovskite light-emitting diode and an enhancement of the EQE from 4.95 to 7.23% at 477 nm.
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