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| 1002. |
- Liu, X., et al.
(författare)
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Numerical study on the energy performance of building zones with transparent water storage envelopes
- 2019
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Ingår i: Solar Energy. - : Elsevier Ltd. - 0038-092X .- 1471-1257. ; , s. 690-706
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Tidskriftsartikel (refereegranskat)abstract
- Researches on water wall passive solar technologies, especially the numerical study on the energy performance of building zones with Transparent Water Storage Envelopes (TWSEs), are reported in this paper. TWSE is a climatic adaptive building envelope consisting of visually transparent modular water containers, exterior shading devices, water supply and return pipes. It is an upgraded water wall that can serve both as an energy efficient facade and an auxiliary water cistern in a building. Currently the energy simulation involving transparent water walls cannot be explicitly done in all energy simulation programs because transparent envelopes are always predefined as the surfaces without thermal mass due to the embedded algorithms complied with ISO15099 standard. A numerical approach based on the integrated energy and computational fluid dynamics (IE&CFD) simulation was developed for solving the energy simulation problem related with TWSEs. A simplified optical model of TWSE was proposed and validated through light transmission testing. Meanwhile, cooling and heating loads of a zone with TWSEs and conventional glazing in summer and winter months were studied. The thermal performance of a TWSE relative to the conventional glazing was also investigated via the comparative thermal box testing. Based on the simulation and testing results, it reveals that TWSEs can exceed most high performance coated glazing with regard to solar radiation control, and they are also exceptional energy efficient transparent envelopes that can outperform the ASHRAE standard window and conventional glazing in terms of cooling and heating load reduction as long as being configured and operated properly according to their physical characteristics and outdoor climatic condition. Furthermore, the innovative technical paradigm of TWSEs, along with the numerical approach developed for their energy simulation, demonstrates a wide range of versatility to be implemented in research and practice for ultra low energy buildings.
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| 1003. |
- Liu, Y., et al.
(författare)
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Amorphous and nanocrystalline Al82Ni10Y8 alloy powder prepared by gas atomization
- 2005
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Ingår i: Intermetallics. - : Elsevier BV. - 0966-9795. ; 13:3-4, s. 393-398
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Tidskriftsartikel (refereegranskat)abstract
- An Al-10Ni-8Y (at.%) alloy was atomized by Ar gas and the morphology, microstructure, thermal stability, phase composition and microhardness of the as-atomized powder were investigated. Most of the powders are spherical in shape, but the surface morphology was different for powder of different size. The cross-section microstructure of powder with size below 15 Pro in diameter showed no detailed feature, indicating existence of amorphous phase or nanocrystalline structure. The as-atomized powder showed four distinct exothermic peaks when heated at 296, 340, 366 and 456 degrees C. The glass transition temperature T-g, crystallization temperature T-x, and the temperature interval of the supercooled liquid region Delta T-x(=T-x-T-g) were detected to be about 266, 288 and 22 degrees C. The Al82Ni10Y8 alloy powder exhibits a high Vickers hardness of 230.6, and shows great potential for structural application. (c) 2004 Elsevier Ltd. All rights reserved.
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| 1004. |
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| 1005. |
- Liu, Y., et al.
(författare)
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Microstructural evolution of Al-Ni-Y powders an with different sizes
- 2005
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Ingår i: Zeitschrift fuer Metallkunde/Materials Research and Advanced Techniques. - 0044-3093. ; 96:1, s. 83-88
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Tidskriftsartikel (refereegranskat)abstract
- An Al-10Ni-8Y (at.%) alloy was atomized by Ar gas atomization in a close-coupled nozzle atomizer. The microstructure, phase composition, and thermal stability of the as-atomized powder were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis and differential scanning calorimetry. Activation energies for different crystallization reactions were calculated using both Kissinger and Ozawa methods. The supercooled liquid region DeltaT(x) (= T(x) - T(g), where T(x) and T(g) are crystallization onset temperature and glass transition temperature, respectively) was detected to be in the range of 14-24 K. Also presented were attempts to determine the critical particle size for amorphous structure.
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| 1006. |
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| 1007. |
- Liu, Z., et al.
(författare)
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Innovative ladder-shaped fin design on a latent heat storage device for waste heat recovery
- 2022
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 321
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Tidskriftsartikel (refereegranskat)abstract
- Latent heat energy storage system provides an alternative solution to solving the imbalance problem of energy supply and demand. To improve the phase change efficiency, a novel ladder-shaped fin is proposed to accelerate melting process. Under the same mass of fin materials, two groups of fin shapes (totally eight cases) are innovatively designed. Upon being verified by experiments in literature, numerical models account for comprehensive descriptions on melting front propagation with emphasizing temperature development and free convection in the liquid phase. Results demonstrate that the ladder-shaped fins can better optimize the melting channel of phase change material than the straight fin. Compared to the original straight fin case, a maximal 52.2% of the total melting time can be saved. The angle change of fins has a significant effect on reducing the melting time of the whole PCM. In Group I where fins are arranged vertically and horizontally, the total melting time is much shorter than that of each corresponding case in Group II (45° from the vertical axis). For the original straight fin in Group II, a 36.8% reduction in total melting time is obtained if turning fins by 45°clockwise. To be conclusive, it is more beneficial to add fins to mobile heat accumulators than to have no fins, saving more energy charging time.
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| 1008. |
- Liu, Z. Y., et al.
(författare)
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Cooling rate effect on Young's modulus and hardness of a Zr-based metallic glass
- 2011
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 509:7, s. 3269-3273
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Tidskriftsartikel (refereegranskat)abstract
- It is known that cooling rate can affect the atomic structure and thus may possibly affect the mechanical properties of metallic glasses (MGs). In spite of the considerable efforts on the cooling rate, its effect on the mechanical properties is controversial at the present time. In this study, we present a micromechanical study of the cooling-rate effect on Young's moduli and hardness of the cast bulks and melt-spun ribbons for a Zr(55)Pd(10)Cu(20)Ni(5)Al(10) metallic glass. Using the classic nanoindentation method, the Young's moduli of the ribbon samples obtained at higher cooling rates were measured which appeared to be much lower than those of the bulk samples. However, through further experiments on slice samples cut from the as-cast bulks and finite-element (FE) analyses, we have clearly demonstrated that the measured difference in elastic moduli was mainly caused by the sample thickness effect in nanoindentation tests. To overcome such a confounding effect, microcompression experiments were performed on the as-cast and as-spun MG samples, respectively. Being consistent with the findings from nanoindentation, the microcompression results showed that the cooling rate, as ranging from similar to 10(2) to similar to 10(6) K/s, essentially has no influence on the Young's modulus and hardness of the metallic glasses. (C) 2010 Elsevier B.V. All rights reserved.
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| 1009. |
- Luo, J., et al.
(författare)
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Accurate targeting in robot-assisted TCM pulse diagnosis using adaptive sensor fusion
- 2019
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Ingår i: Periodicals of engineering and natural sciences. - : International University of Sarajevo. - 2303-4521. ; 7:1, s. 381-387
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Tidskriftsartikel (refereegranskat)abstract
- Accurate targeting plays an important role in the study of human-robot interaction under dynamic environments. Especially for robot-assisted Traditional Chinese Medicine (TCM) pulse diagnosis, the localization and accuracy of diagnose positions at wrist needs to be addressed. In this work, imaging photoplethysmography (iPPG) which measures the physiological changes of blood flow in artery is used as an extra modal information in addition to computer vision at localization, to alleviate the effect of approaching distance varying during the robot arm movement. Both computer vision and iPPG are fed into an adaptive fusion expert of convolutional neural networks (CNN) architecture, and this boosts the accuracy at targeting of TCM radial artery at wrist. A coherence weight of their contributions was calculated and reflected the adaptation of the CNN to distance varying.
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| 1010. |
- Luo, J.L, et al.
(författare)
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Impact of diagenesis on reservoir-quality evolution in fluvial and lacustrine-deltaic sandstones: evidence from Jurassic and Triassic sandstones from the Ordos Basin, China
- 2009
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Ingår i: Journal of Petroleum Geology. - : Wiley. - 0141-6421 .- 1747-5457. ; 32:1, s. 79-102
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Tidskriftsartikel (refereegranskat)abstract
- The reservoir quality of Jurassic and Triassic fluvial and lacustrine-deltaic sandstones in the intracratonic Ordos Basin is strongly influenced by depositional facies and various types of diagenetic modifications. The fluvial sandstones have higher average He-porosity and permeability (14.8% and 12.7 mD, respectively) than the deltaic sandstones (9.8% and 5.8 mD, respectively). In addition to extensive mechanical compaction, eodiagenesis (220-97 Ma; depth < 2000 m; T < 70 degrees C) has resulted in dissolution and kaolinitization of detrital silicates in the Jurassic fluvial sandstones, and in smectite infiltration and minor cementation by calcite and siderite in the Triassic fluvial and deltaic sandstones. Pervasive eogenetic carbonate cementation (> 20 vol.%) occurred in Triassic deltaic siltstones and very fine-grained sandstones which are closely associated with organic-rich mudstones. Mesodiagenesis (97-65 Ma), which occurred during rapid subsidence to depths of 3700-4400 m, resulted in the albitization of plagioclase, checmical compaction, the conversion of kaolinite into dickite, and cementation by quartz overgrowths, chlorite, illite, ankerite (delta C-13(VPDB) = -2.4 parts per thousand to +2.6 parts per thousand; delta O-18(VPDB) = -21.5 parts per thousand to -10 parts per thousand) and calcite (delta C-13(VPDB) = -4.7 parts per thousand to +3.7 parts per thousand; delta O-18(VPDB) = -21.8 parts per thousand to -13.4 parts per thousand). Oil emplacement (95 Ma) retarded cementation by mesogenetic quartz and carbonate but had little influence on dickite, illite and chlorite formation. Retardation of quartz cementation was also due to the presence of chlorite fringes around detrital quartz grains. Dickitization of eogenetic kaolinite together with the short residence time at maximum burial temperatures (105-124 degrees C) has retarded the albitization of K-feldspars and illite formation and hence prevented severe permeability destruction. Telodiagenesis, which occurred after uplift (Eocene to end-Neogene), caused slight dissolution and kaolinitization of feldspars. This study demonstrates that despite complex patterns of diagenetic modifications in the Triassic and Jurassic successions, depositional porosity and permeability are better preserved in fluvial meandering channel sandstones than in deltaic sandstones. These results should be important for modelling of reservoir-quality distribution and exploration risk evaluation in the basin.
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