| 1. |
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| 2. |
- Fu, Yuxiang, et al.
(författare)
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Congestion-Aware Dynamic Elevator Assignment for Partially Connected 3D-NoCs
- 2019
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Ingår i: 2019 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS (ISCAS). - : IEEE. - 9781728103976
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Konferensbidrag (refereegranskat)abstract
- The combination of Network-on-Chips (NoCs) and 3D IC technology, 3D NoCs, has been proven to be able to achieve a great improvement in both network performance and power consumption compared to 2D NoCs. In the traditional 3D NoC, all routers are vertically connected. Due to the large overhead of Through-Silicon-Via (TSV, e.g., low fabrication yield and the occupied silicon area), the partially connected 3D NoC has emerged. The assignment method determines the traffic loads of the vertical links (elevators), thus has a great impact on 3D-NoCs' performance. In this paper, we propose a congestion-aware dynamic elevator assignment (CDA) scheme, which takes both the distance factors and network congestion information into account. Experiments show that the performance of the proposed CDA scheme is improved by 67% to 87% compared to the random selection scheme, 8% to 25% compared to SelByDis-1, and 13% to 18% compared to SelByDis-2.
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| 3. |
- Li, Guoqiang, et al.
(författare)
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A comprehensive dataset of luminescence chronologies and environmental proxy indices of loess-paleosol deposits across Asia
- 2024
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Ingår i: npj Climate and Atmospheric Science. - : Springer Nature. - 2397-3722. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Loess-paleosol sequences have been used in Asia to study climate and environmental changes during the Quaternary. The scarcity of age control datasets and proxy indices analysis data for Asian loess has limited our understanding of loess depositional processes and the reconstruction of paleoclimatic changes from loess-paleosol records. In this study, we present a dataset that includes 1785 quartz optically stimulated luminescence ages and 1038 K-feldspar post-infrared infrared stimulated luminescence ages from 128 loess-paleosol sequences located in different regions of Asia. We generate 38 high-resolution age-depth models of loess records based on the provided datasets. We provide data on 12,365 grain size records, 14,964 magnetic susceptibility records, 2204 CaCO3 content records, and 3326 color reflection records. This dataset contains the most detailed and accurate chronologies and proxy index data for loess records in Asia yet published. It provides fundamental data for understanding the spatial-temporal variations in loess depositional processes and climatic changes across the continent during the mid-late Quaternary.
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| 4. |
- Li, Guoqiang, et al.
(författare)
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Differential ice volume and orbital modulation of Quaternary moisture patterns between Central and East Asia
- 2020
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Ingår i: Earth and Planetary Science Letters. - : Elsevier. - 0012-821X .- 1385-013X. ; 530
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Tidskriftsartikel (refereegranskat)abstract
- Desertification is of pressing environmental concern in large parts of Asia and directly affects millions of people. Arid Central Asia (ACA) in particular is highly sensitive to desertification and environmental change. Climate change in ACA may be driven by westerly circulation or monsoon variation. However, no consensus exists over their relative importance during the Quaternary and this greatly restricts our understanding of how this region may be affected by future climate change. Here we use the most detailed luminescence dating age model yet produced for ACA for three loess records in the Tianshan Mountains spanning the past 250 ka to show a sharp dichotomy in moisture variation between lowland and high mountain areas. The lowland areas of ACA are subjected to persistent aridity during past 250 ka, while highland areas clearly show dry-glacial and moist-interglacial changes, synchronous to moisture variability in monsoonal East Asia, and both co-varying with global ice volume and greenhouse gas (GHG) variation. In contrast, moisture variability across ACA within interglacials varies inversely with insolation-driven precessional changes. This is directly out of phase with the moisture changes of East Asia, which co-vary with precessional insolation changes, and indicates the influence of Westerly circulation in ACA. Our Flexible Global Ocean-Atmosphere-Land System model simulations further reveal that coupled ice volume and GHG variations dominated climatic variability in both ACA and East Asia over glacial-interglacial cycles. However, the out of phase relationship between the intensity of the Westerly and East Asian monsoon systems during interglacial periods indicates that precessional forcing is responsible for differences in moisture patterns between ACA and East Asia. These observations indicate that moisture levels will not increase even in high altitude regions of ACA over the next several millennia; rather desertification is likely to worsen resulting from stabilization of the Westerlies as a result of low summer insolation.
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| 5. |
- Zhang, Shu, et al.
(författare)
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Mitigating the Jahn-Teller distortion driven by the spin-orbit coupling of lithium manganate cathode
- 2022
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Ingår i: Journal of Energy Challenges and Mechanics. - : Elsevier BV. - 2056-9386. ; 72, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- Spinel LiMn2O4 is recognized as one of the most competitive cathode candidates for lithium-ion batteries ascribed to environmentally benign and rich sources. However, the wholesale application of LiMn2O4 is predominately plagued by its severe capacity degradation, mainly associated with the innate Jahn-Teller effect. Herein, single-crystalline LiMn2O4 with Eu3+ doping is rationally designed to mitigate the detrimental Jahn-Teller distortion by tuning the chemical environment of MnO6 octahedra and accommodating localized electron, based on the unique aspheric flexible 4f electron orbit of rare-earth metal ions. Notably, the stretching of MnO6 octahedron stemmed from the Jahn-Teller effect in Eu-doped LiMn2O4 is effectively suppressed, confirmed by theoretical calculation. Meanwhile, the structural stability of the material has been significantly enhanced due to the robust Mn–O band coherency and weakened phase transition, proved by synchrotron radiation absorption spectrum and operando X-ray diffraction. The corresponding active cathode manifests superior long-cycle stability after 300 loops at 2C and displays only a 0.011% capacity drop per cycle even at 5C. Given this, this modification tactic sheds new light on achieving superior long-cycle performances by suppressing distortion in various cathode materials.
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| 6. |
- Zhang, Xing, et al.
(författare)
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Diagnosing NB plasmas on the EAST tokamak with new time-of-flight neutron spectrometer
- 2014
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 54:10, s. 104008-
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Tidskriftsartikel (refereegranskat)abstract
- The new neutron spectrometer time-of-flight enhanced diagnostics (TOFED) for the EAST tokamak is presented and its characteristics are described in terms of simulation results, as well as the interface in the torus hall along with new neutral beam (NB) injectors. The use of TOFED for studies of the slowing down of NB-injected deuterons is illustrated. The implications of measuring the neutron emission on a long pulse machine are discussed together with the experimental challenges and diagnostic possibilities approaching those to be encountered in continuous operation.
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| 7. |
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| 8. |
- Chen, Nan, et al.
(författare)
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Enhancement of an additive-manufactured austenitic stainless steel by post-manufacture heat-treatment
- 2019
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 759, s. 65-69
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Tidskriftsartikel (refereegranskat)abstract
- The effect of post-manufacture heat-treatment on the mechanical strength of an additively-manufactured austenitic stainless steel has been investigated. Microstructural investigations revealed that the as-manufactured material exhibited a multi-scale structure, composed of grains, cells, dislocations and nano-sized particles. Annealing at 400 degrees C resulted in a 10% increase in yield strength, associated with the additional precipitation of a population of nano-sized silicates. Annealing at higher temperatures resulted in a decrease in strength, attributed primarily to the thermal instability of the cell structure in the as-manufactured material. The results demonstrate that by careful control of annealing conditions the structure and mechanical properties of additively-manufactured austenitic stainless steel can be optimized by post-manufacture heat-treatment.
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| 9. |
- Chen, Pan, et al.
(författare)
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Quantifying the Contribution of the Dispersion Interaction and Hydrogen Bonding to the Anisotropic Elastic Properties of Chitin and Chitosan
- 2022
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 23:4, s. 1633-1642
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Tidskriftsartikel (refereegranskat)abstract
- The elastic tensors of chitin and chitosan allomorphs were calculated using density functional theory (DFT) with and without the dispersion correction and compared with experimental values. The longitudinal Young's moduli were 114.9 or 126.9 GPa for alpha-chitin depending on the hydrogen bond pattern: 129.0 GPa for beta-chitin and 191.5 GPa for chitosan. Furthermore, the moduli were found to vary between 17.0 and 52.8 GPa in the transverse directions and between 2.2 and 15.2 GPa in shear. Switching off the dispersion correction led to a decrease in modulus by up to 63%, depending on the direction. The transverse Young's moduli of a-chitin strongly depended on the hydroxylmethyl group conformation coupled with the dispersion correction, suggesting a synergy between hydrogen bonding and dispersion interactions. The calculated longitudinal Young's moduli were, in general, higher than experimental values obtained in static conditions, and the Poisson's ratios were lower than experimental values obtained in static conditions.
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| 10. |
- Hashemi Sanatgar, Razieh, 1983-, et al.
(författare)
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Piezoresistive Properties of 3D-Printed Polylactic Acid (PLA) Nanocomposites
- 2022
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Ingår i: Polymers. - : MDPI. - 2073-4360. ; 14:15
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Tidskriftsartikel (refereegranskat)abstract
- An increasing interest is focused on the application of 3D printing for sensor manufacturing. Using 3D printing technology offers a new approach to the fabrication of sensors that are both geometrically and functionally complex. This work presents the analysis of the 3D-printed thermoplastic nanocomposites compress under the applied force. The response for the corresponding resistance changes versus applied load is obtained to evaluate the effectiveness of the printed layer as a pressure/force sensor. Multi-walled carbon nanotubes (MWNT) and high-structured carbon black (Ketjenblack) (KB) in the polylactic acid (PLA) matrix were extruded to develop 3D-printable filaments. The electrical and piezoresistive behaviors of the created 3D-printed layers were investigated. The percolation threshold of MWNT and KB 3D-printed layers are 1 wt.% and 4 wt.%, respectively. The PLA/1 wt.% MWNT 3D-printed layers with 1 mm thickness exhibit a negative pressure coefficient (NPC) characterized by a decrease of about one decade in resistance with increasing compressive loadings up to 18 N with a maximum strain up to about 16%. In the cyclic mode with a 1 N/min force rate, the PLA/1 wt.% MWNT 3D-printed layers showed good performance with the piezoresistive coefficient or gauge factor (G) of 7.6 obtained with the amplitude of the piezoresistive response (Ar) of about -0.8. KB composites could not show stable piezoresistive responses in a cyclic mode. However, under high force rate compression, the PLA/4 wt.% KB 3D-printed layers led to responses of large sensitivity (Ar = −0.90) and were exempt from noise with a high value of G = 47.6 in the first cycle, which is a highly efficient piezoresistive behavior.
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| 11. |
- Iyer, Sweta, 1987-, et al.
(författare)
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Study of photoluminescence property on cellulosic fabric using multifunctional biomaterials riboflavin and its derivative Flavin mononucleotide
- 2019
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Ingår i: Scientific Reports. - London : Nature Publishing Group. - 2045-2322. ; :9
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Tidskriftsartikel (refereegranskat)abstract
- Flavins are ubiquitous in nature and participate in various biochemical reactions mainly in the form of coenzyme Flavin mononucleotide (FMN) or as precursor such as Riboflavin (RF). Both flavins, RF and FMN are multifunctional bio-based molecules yielding yellow coloration and exhibit photoluminescence, UV protection, and redox properties. The aim of the present research study was to investigate the diffusion method as a technique to obtain photoluminescent cellulosic fabric using multifunctional RF and FMN. The photoluminescent moiety RF and FMN exhibited three maximum absorbance peaks at about 270 nm, 370 nm and 446 nm in aqueous solution at pH 7. The solutions of RF and FMN with concentration 4% and 20% (owf) at pH 7 were prepared and used in diffusion method for cellulosic fabric dyeing. The study involved the determination of color performance and evaluation of luminescence property of the dyed fabric using UV-visible spectrophotometer and photoluminescence spectroscopy, respectively. Under monochromatic UV lamp exposure emitting at 370 nm, the dyed fabric showed an intense emission of greenish yellow color, which was later confirmed by the intense photoluminescence observed at a wavelength of about 570 nm. The study demonstrates the theoretical evaluation of quantum efficiency (φ) obtaining maximum φ value of 0.28. Higher color strength value and improved wash fastness were obtained by treatment with different biobased mordants such as tannic acid and citric acid as well as calcium chloride for both RF and FMN. Additionally, ultraviolet (UV) protection ability for both RF and FMN dyed fabric were determined and showed UPF factor of 50+ and 35 respectively. The work allowed us to explore the photoluminescence property of riboflavin and Flavin mononucleotide for its application in the field of textiles as a new scope of producing photoluminescent textile along with multifunctional properties such as coloration and UV protection.
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| 12. |
- Li, Guoqiang, et al.
(författare)
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Orbital scale lake evolution in the Ejina Basin, central Gobi Desert, China revealed by K-feldspar luminescence dating of paleolake shoreline features
- 2018
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Ingår i: Quaternary International. - : Elsevier BV. - 1040-6182 .- 1873-4553. ; 482, s. 109-121
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Tidskriftsartikel (refereegranskat)abstract
- The Ejina Basin in the central Gobi Desert contains the terminal lakes of the Heihe River. Paleoenvironmental changes in the basin are important since its deposits are a significant source of Northern Hemisphere dust. In this study we employed a K-feldspar pIRIR dating technique to date shoreline features <= 940 m at multiple locations in the Ejina Basin similar to 45-50 m above the modern basin floor. Internal checks of luminescence characteristics were employed to test the reliability of the pIRIR dating. In combination with our previously reported stratigraphy and chronology of shorelines at <= 927 m in the Ejina Basin, these results imply that a paleolake was present in the basin prior to similar to 350 ka. Other high stands in the basin occurred at similar to 320-310 ka, 240-180 ka, 120-80 ka, and similar to 5 ka, corresponding to MIS 9, MIS 7, MIS 5 and the mid Holocene (MIS 1), respectively, indicating a strong link with glacial-interglacial cycles. Extensions of the East Asian Summer Monsoon (EASM) during interglacial periods, possibly interacting with the Westerlies, apparently caused higher precipitation and lake formation. The impact of orbital eccentricity on the EASM/Westerlies appears to be responsible for the formation of major lake/desert cycles on the northeastern margin of the Tibetan Plateau.
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| 13. |
- Morshed, Mohammad Neaz, Mr. 1992-, et al.
(författare)
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Surface modification of polyester fabric using plasma-dendrimer for robust immobilization of glucose oxidase enzyme
- 2019
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Ingår i: Scientific Reports. - Germany : Nature Publishing Group. - 2045-2322.
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Tidskriftsartikel (refereegranskat)abstract
- Robust immobilization of glucose oxidase (GOx) enzyme was achieved on poly(ethylene terephthalate) nonwoven fabric (PN) after integration of favourable surface functional groups through plasma treatments [atmospheric pressure-AP or cold remote plasma-CRP (N2 + O2)] and/or chemical grafting of hyperbranched dendrimers [poly-(ethylene glycol)-OH or poly-(amidoamine)]. Absorption, stability, catalytic behavior of immobilized enzymes and reusability of resultant fibrous bio-catalysts were comparatively studied. Full characterization of PN before and after respective modifications was carried out by various analytical, instrumental and arithmetic techniques. Results showed that modified polyester having amine terminal functional groups pledged better surface property providing up to 31% enzyme loading, and 81% active immobilized enzymes. The activity of the enzyme was measured in terms of interaction aptitude of GOx in a given time to produce hydrogen peroxide using colorimetric assay. The immobilized GOx retained 50% of its original activity after being reused six (06) times and exhibited improved stability compared with the free enzyme in relation to temperature. The reaction kinetics, loading efficiency, leaching, and reusability analysis of enzyme allowed drawing a parallel to the type of organic moiety integrated during GOx immobilization. In addition, resultant fibrous bio-catalysts showed substantial antibacterial activity against pathogenic bacteria strains (Staphylococcus epidermidis and Escherichia coli) in the presence of oxygen and glucose. These results are of great importance because they provide proof-of-concept for robust immobilization of enzymes on surface-modified fibrous polyester fabric for potential bio-industrial applications.
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| 14. |
- Qiang, Mingrui, et al.
(författare)
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Late Quaternary Dust, Loess and Desert Dynamics in Upwind Areas of the Chinese Loess Plateau
- 2021
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Ingår i: Frontiers in Earth Science. - : Frontiers Media S.A.. - 2296-6463. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- As a key global climate and dust archive, the nature of Chinese loess generation, transport and deposition remains debated. The lack of consensus on dust dynamics from sources to leeward regions fundamentally limits interpretation of the preserved past climate and dust record. Here, we investigate chronostratigraphic variability of aeolian deposits in upwind regions of the modern Chinese Loess Plateau (CLP) and attempt to understand dust dynamics that potentially affects loess deposition downwind. The strata consist of alternating layers of typical loess, well-sorted sand, and sandy loess, with obvious unconformities occurring at the transitions from loess to sand. We suggest that pre-existing typical loess in regions to the northwest of the modern CLP was eroded by wind, providing a significant source of homogeneous dust for the dust deposits downwind. The sand deposits interbedded with typical loess at the study sites suggests that proximal deserts have greatly expanded and contracted repeatedly prior to the Holocene. However, the spatial extents of the deserts, as inferred from the sections here, have not markedly diminished after the major expansion during the Last Glacial Maximum. Such a pattern of proximal desert dynamics plays an important role in regulating dust emission and transport, strongly affecting dust sequences on the CLP. Our results suggest a complex scenario of dust dynamics in upwind regions of the CLP at least over the Late Quaternary; the involved processes have to be considered when using conventional proxies from Chinese loess deposits to recover the history of climate and dust changes.
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| 15. |
- Sun, Guoqiang, et al.
(författare)
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Low temperature self-healing character of asphalt mixtures under different fatigue damage degrees
- 2019
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Ingår i: Construction and Building Materials. - : ELSEVIER SCI LTD. - 0950-0618 .- 1879-0526. ; 223, s. 870-882
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Tidskriftsartikel (refereegranskat)abstract
- The primary objective of this study is to advance the understanding of the low temperature self-healing character of asphalt mixtures under different damage degrees, thus to determine the effective strategy of asphalt pavement maintenance. Firstly, three kinds of asphalt mixtures are selected to conduct the indirect tensile (IDT) fatigue test to a certain fatigue damage degree at low temperatures, and then the resilient modulus (Mr) at different rest time is measured to quantify the healing potential. Next, the fatigue loading with different intermittent time (0 s, 1 s and 3 s) is applied to determine the impact of intermittent time on healing potential. The results indicate that the descending order of healing potential of asphalt mixtures is: SMA-11 > AC-8 > AC-11 at 5 degrees C and -5 degrees C. The loading intermittent time has an obvious effect on the fatigue damage state of asphalt mixtures, while the longer the intermittent time, the less the effect on fatigue damage healing. Besides, the fatigue damage state has great influence on its healing potential of asphalt mixture. Under the low damage conditions, the initial healing rate is greater than the long term healing rate. However, the low temperature (-5 degrees C) dramatically reduces the healing rate of asphalt mixtures, and causes their long-term healing rate to stabilize gradually to a very low level. Especially under the high fatigue damage conditions, the healing potential of asphalt mixtures will almost disappear at -5 degrees C. Furthermore, together with meso-scale Computed Tomography (CT) scanning technique, it is found that the intemal crack distribution characteristics of different graded asphalt mixtures are different even under the same damage degree, which may explain the differences in the healing potential of asphalt mixtures. The use of a fast two-dimensional (2D) scanning technology further confirms that the crack zones inside the asphalt mixture are gradually shrinking after a period of high temperature healing. Finally, the Grey relational analysis reveals that the healing time has the most significant influence on the healing potential of asphalt mixtures. The gradation type and temperature have the similar influence level on the healing potential. The correlation degree between the fatigue damage degree and healing potential is the smallest compared with the other three factors. All rights reserved.
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| 16. |
- Sun, He, et al.
(författare)
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Increased glacier melt enhances future extreme floods in the southern Tibetan Plateau
- 2024
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Ingår i: Advances in Climate Change Research. - 1674-9278 .- 2524-1761.
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Tidskriftsartikel (refereegranskat)abstract
- Mountainous areas are of special hydrological concern because topography and atmospheric conditions can result in large and sudden floods, posing serious risks to water-related safety in neighbouring countries. The Yarlung Zangbo (YZ) River basin is the largest river basin on the Tibetan Plateau (TP), but how floods will discharge in this basin and how the role of glacier melt in floods will change throughout the 21st-century under shared socioeconomic pathways scenarios (SSP2-4.5 and SSP5-8.5) remain unclear. Here, we comprehensively address this scientific question based on a well-validated large-scale glacier-hydrology model. The results indicate that extreme floods was projected to increase in the YZ basin, and was mainly reflected in increased duration (4–10 d per decade) and intensity (153–985 m3 s−1 per decade). Glacier runoff was projected to increase (2–30 mm per decade) throughout the 21st-century, but there was also a noticeable decrease or deceleration in glacier runoff growth in the late first half of the century under the SSP2-4.5, and in the latter half of the century under the SSP5-8.5. Glacier melt was projected to enhance the duration (12%–23%) and intensity (15%–21%) of extreme floods under both SSPs, which would aggravate the impact of future floods on the socioeconomics of the YZ basin. This effect was gradually overwhelmed by precipitation-induced floods from glacier areas to YZ outlet. This study takes the YZ basin as a projection framework example to help enrich the understanding of future flood hazards in basins affected by rainfall- or meltwater across the TP, and to help policy-makers and water managers develop future plans.
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| 17. |
- Tadesse Abate, Molla, et al.
(författare)
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Colouration and bio-activation of polyester fabric with curcumin in supercritical CO2 : Part II – Effect of dye concentration on the colour and functional properties
- 2019
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446 .- 1872-8162.
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Tidskriftsartikel (refereegranskat)abstract
- This study presents a sustainable approach to the fabrication of multifunctional polyester fabric with bioactive natural colourant curcumin through a water free supercritical CO2 dyeing technique. A simple dyeing process was carried out in which curcumin powder dye was directly applied to polyester fabric in scCO2 medium without involving mordant chemicals and fabric pre-treatment procedures. The colour, bioactivity, and durability properties of the dyed samples were characterized. Results showed that the colour strength increases when the dye concentration increases and higher colour strength (K/S value above 17) could be achieved using low curcumin concentration (ca. 0.75% owf). Moreover, the dyed fabrics displayed desirable antimicrobial, antioxidant, and UV-protection activities with acceptable colour fastness to washing and rubbing. This study opens a new view towards the sustainable fabrication of coloured and bioactive polyester fabric using curcumin via a resource-efficient and eco-friendly scCO2 dyeing technique.
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| 18. |
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| 19. |
- Tadesse Abate, Molla, et al.
(författare)
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Single-step disperse dyeing and antimicrobial functionalization of polyester fabric with chitosan and derivative in supercritical carbon dioxide
- 2019
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Ingår i: Journal of Supercritical Fluids. - : Elsevier BV. - 0896-8446 .- 1872-8162. ; 147, s. 231-240
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a novel green approach was adopted to develop antimicrobial polyester fabric using sustainable biopolymers (chitosan/derivative) as eco-friendly antimicrobial agents via the resource efficient supercritical CO2 (scCO2) dyeing route in a single step. Polyester fabric was dyed with a small amount of dye (0.4% owf) in the presence of chitosan/derivative (3% owf) in scCO2 at 120 °C, 25 MPa for 1 h. The success of chitosan/derivative impregnation was confirmed by Fourier Transform Infrared (FTIR), Zeta Potential (ζ), Scanning Electron Microscopy (SEM), and Water Contact Angle (WCA) measurements. According to the result, excellent color strength and fastness properties were obtained and the treated samples also reduced 75 − 93% of Escherichia coli (ATCC 25922) bacteria within one hour. This suggests that the dye and chitosan/derivative had no adverse effect on each other, proving compatibility. This new approach would help to reduce the cost of production and environmental pollution associated with the conventional textile finishing processes.
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| 20. |
- Tadesse Abate, Molla, et al.
(författare)
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Supercritical CO2 dyeing of polyester fabric with photochromic dyes to fabricate UV sensing smart textiles
- 2020
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Ingår i: Dyes and pigments. - : Elsevier. - 0143-7208 .- 1873-3743. ; 183
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Tidskriftsartikel (refereegranskat)abstract
- Photochromic molecules are well-established colourants in the manufacturing of niche products, providing reversible colour change effects when irradiated with ultraviolet (UV) light. The high material cost of such speciality dyes along with the general high carbon footprint and extensive water consumption of textile products necessitates resource-efficient production processes. The use of supercritical CO2 (scCO(2)) dyeing technique enables the economic production of textile high-end products, where a uniform through colouration is desired. This study investigates the potential application of two commercial photochromic dyes based on spirooxazine (Sea Green - SO-SG) and naphthopyran (Ruby Red - NP-RR) to polyester fabric using scCO(2) dyeing technique and examines their photochromic behaviour. The dyeing was carried out at 120 degrees C and 25 MPa for 1 h. The photochromic performance was evaluated using a specially designed online colour measurement system capable of simultaneous UV irradiation and continuous measurement of photochromic colour change even after the shutdown of the UV source. The colour yields (K/S values), photoswitching rates and durability against washing were the main parameters examined. The results showed that scCO(2) dyed photochromic polyester fabrics exhibited reversible colour changing properties upon UV exposure and removal. The samples dyed with SO-SG demonstrated a comparable degree of photo-colouration, lower background colour, faster colouration and decolouration speeds, but inferior wash fastness compared with NP-RR dyed samples. Particularly, the same class of dyes applied by scCO(2) dyeing showed faster fading rates compared with conventionally dyed and screen printed samples. This study shows that scCO(2) dyeing method is a potential alternative to develop uniformly coloured photochromic textiles providing excellent photochromic performance with additional economic and environmental benefits.
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| 21. |
- Tadesse Abate, Molla, et al.
(författare)
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Supercritical CO2 Technology in Resource-effective Production of Functional and Smart Textiles
- 2022
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Ingår i: Journal of Fiber Bioengineering and Informatics. - : Textile Bioengineering and Informatics Society. - 1940-8676 .- 2617-8699. ; 15:1, s. 35-44
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this work was to investigate the potential application of scCO2 dyeing technology to produce functional and smart textiles. Selected dyes and functional agents were applied to polyester fabric using the scCO2 impregnation technique. The effects of the processing variables on the functional and colour performances were explored. The results showed that scCO2 is a viable technique to produce functional polyester fabric in a resource-efficient and eco-friendly way. Dyed polyester fabric with additional functionalities such as antimicrobial, antioxidant, UV protection, and UV sensing properties were realised. The fabrics developed have demonstrated desirable colour and functional properties without affecting each other confirming compatibility. Moreover, the functional fabrics exhibited the required durability and fastness properties sufficient for various applications. This research project contributes towards widening the application of the supercritical CO2 dyeing technique and paves a way for sustainable production of functional and smart textiles in a resource-efficient and eco-friendly way.
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| 22. |
- Wong, Kwan-Yee Kenneth, et al.
(författare)
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A Stratified Approach for Camera Calibration Using Spheres
- 2011
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Ingår i: IEEE Transactions on Image Processing. - 1057-7149 .- 1941-0042. ; 20:2, s. 305-316
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a stratified approach for camera calibration using spheres. Previous works have exploited epipolar tangents to locate frontier points on spheres for estimating the epipolar geometry. It is shown in this paper that other than the frontier points, two additional point features can be obtained by considering the bitangent envelopes of a pair of spheres. A simple method for locating the images of such point features and the sphere centers is presented. An algorithm for recovering the fundamental matrix in a plane plus parallax representation using these recovered image points and the epipolar tangents from three spheres is developed. A new formulation of the absolute dual quadric as a cone tangent to a dual sphere with the plane at infinity being its vertex is derived. This allows the recovery of the absolute dual quadric, which is used to upgrade the weak calibration to a full calibration. Experimental results on both synthetic and real data are presented, which demonstrate the feasibility and the high precision achieved by our proposed algorithm.
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| 23. |
- Zhang, Chen, et al.
(författare)
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Resilient cooling strategies – A critical review and qualitative assessment
- 2021
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 251
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Tidskriftsartikel (refereegranskat)abstract
- The global effects of climate change will increase the frequency and intensity of extreme events such as heatwaves and power outages, which have consequences for buildings and their cooling systems. Buildings and their cooling systems should be designed and operated to be resilient under such events to protect occupants from potentially dangerous indoor thermal conditions. This study performed a critical review on the state-of-the-art of cooling strategies, with special attention to their performance under heatwaves and power outages. We proposed a definition of resilient cooling and described four criteria for resilience—absorptive capacity, adaptive capacity, restorative capacity, and recovery speed —and used them to qualitatively evaluate the resilience of each strategy. The literature review and qualitative analyses show that to attain resilient cooling, the four resilience criteria should be considered in the design phase of a building or during the planning of retrofits. The building and relevant cooling system characteristics should be considered simultaneously to withstand extreme events. A combination of strategies with different resilience capacities, such as a passive envelope strategy coupled with a low-energy space-cooling solution, may be needed to obtain resilient cooling. Finally, a further direction for a quantitative assessment approach has been pointed out.
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| 24. |
- Zhong, Guoqiang, et al.
(författare)
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Classification of photographed document images based on deep-learning features
- 2017
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Ingår i: Eighth International Conference on Graphic and Image Processing (ICGIP 2016). - : SPIE - International Society for Optical Engineering. - 9781510609518 - 9781510609525
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose two new problems related to classification of photographed document images, and based on deep learning methods, present the baseline solutions for these two problems. The first problem is that, for some photographed document images, which book do they belong to? The second one is, for some photographed document images, what is the type of the book they belong to? To address these two problems, we apply “AexNet” to the collected document images. Using the pre-trained “AlexNet” on the ImageNet data set directly, we obtain 92.57% accuracy for the book-name classification and 93.33% accuracy for the book-type one. After fine-tuning on the training set of the photographed document images, the accuracy of the book-name classification increases to 95.54% and that of the booktype one to 95.42%. To our best knowledge, although there exist many image classification algorithm, no previous work has targeted to these two challenging problems. In addition, the experiments demonstrate that deep-learning features outperform features extracted with traditional image descriptors on these two problems.
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| 25. |
- Zhu, Lianghong, et al.
(författare)
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Phase Current Reconstruction Error Suppression Method for Single DC-Link Shunt PMSM Drives at Low-Speed Region
- 2022
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Ingår i: IEEE transactions on power electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8993 .- 1941-0107. ; 37:6, s. 7067-7081
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Tidskriftsartikel (refereegranskat)abstract
- The extensive application of vector phase shift modulation method in permanent magnet synchronous motor drive systems with single dc-link current sensor results in obvious current ripple in the low-speed region. The patterns of these ripples vary greatly in different sectors, leading to nonnegligible phase current reconstruction errors. In this article, an estimation of the local average current change rate (ELAC(2)R) based reconstruction error suppression method within the switching cycle is proposed to resolve this problem. By comparing the actual and the ideal sampling points, the increase of current ripple and the reconstruction error caused by the combination of the vector phase shift and the single current sensor sampling in the low-speed region are modelled and analyzed. Then according to equivalent modelling of the current ripple between the ideal and the actual sampling points, the more accurate phase current information can be quickly obtained based on the sampling value. The compensation process is significantly simplified and the computation burden of the processor is reduced. Experimental results show that the performance of current reconstruction can be improved effectively with less harmonic content with the proposed method.
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