•Blended plasmonic nanofluid was manufactured by mixing three different Au Nanorods.•The manufactured nanofluid showed broad-band absorption in the solar spectrum.•Theoretical model of solar ...radiation to heat conversion was experimentally verified.
In this paper, thermal performance of a flat-plate volumetric solar collector using a blended plasmonic nanofluid as its heat transfer fluid was investigated. The blended plasmonic nanofluid used in the experiment was manufactured based on three different aspect ratios of gold nanorods (AuNRs), and it was designed to have broad-band absorption over the visible and near-infrared spectrum. The conversion process of solar radiation to heat in the blended plasmonic nanofluid was verified experimentally by measuring the temperature distribution inside the nanofluid under illumination of a tungsten–halogen lamp and by comparing it with the simulation result. Through the theoretical investigation of a flat-plate volumetric solar collector, effects of channel depth, channel length, mass flow rate, and the magnitude absorption coefficient of the blended plasmonic nanofluid were characterized in order to establish a basic design. The results of this study will facilitate the development of highly efficient solar thermal collectors using plasmonic nanofluids.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Plasmonic nanofluids has been reported beneficial for enhancing absorption of the solar energy in a direct-absorption solar collector (DASC). In order to overcome the shortage of narrow absorption ...band associated with the localized surface plasmon, two strategies can be adopted. One is to blend nanoparticles with different absorption peaks, and the other is to develop nanoparticles capable of exhibiting multiple absorption peaks at different wavelengths. In this study, the latter strategy is explored systematically by investigating the absorption efficiency of metallic nanoparticles with sharp edges. The results show that the Ag nanoparticles with sharp edges can induce multiple absorption peaks due to both localized surface plasmon resonance and lightning rod effect. We also show that the sharper edges (i.e., with either smaller radius of curvature or smaller edge angle) can greatly enhance the lightning rod effect. In addition, the study of SiO2-core/Ag-shell suggests that the core/shell configuration is beneficial for further broadening the absorption band compared to the Ag nanoparticle. Further investigation shows that the solar-weighted absorption coefficient of a DASC using the four-edge nanoparticle is 35% and 20% point higher than the nanosphere and the nanorod respectively with a fixed volume fraction of 10−6.
•Ag nanoparticles with sharp edges can generate multiple absorption peaks.•Multiple peaks are due to the localized surface plasmon and the lightning rod effect.•More edges do not necessarily result in broader absorption.•Core/shell nanoparticles exhibit broader absorption band than the Ag nanoparticles.•Performance of a DASC with edged particles is much higher than smooth particles.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Glucose metabolism is a mechanism by which energy is produced in form of adenosine triphosphate (ATP) by mitochondria and precursor metabolites are supplied to enable the ultimate enrichment of ...mature metabolites in the cell. Recently, glycolytic enzymes have been shown to have unconventional but important functions. Among these enzymes, pyruvate kinase M2 (PKM2) plays several roles including having conventional metabolic enzyme activity, and also being a transcriptional regulator and a protein kinase. Compared with the closely related PKM1, PKM2 is highly expressed in cancer cells and embryos, whereas PKM1 is dominant in mature, differentiated cells. Posttranslational modifications such as phosphorylation and acetylation of PKM2 change its cellular functions. In particular, PKM2 can translocate to the nucleus, where it regulates the transcription of many target genes. It is notable that PKM2 also acts as a protein kinase to phosphorylate several substrate proteins. Besides cancer cells and embryonic cells, astrocytes also highly express PKM2, which is crucial for lactate production via expression of lactate dehydrogenase A (LDHA), while mature neurons predominantly express PKM1. The lactate produced in cancer cells promotes tumor progress and that in astrocytes can be supplied to neurons and may act as a major source for neuronal ATP energy production. Thereby, we propose that PKM2 along with its different posttranslational modifications has specific purposes for a variety of cell types, performing unique functions.
Pyruvate kinase M2 (PKM2) is crucial for cell proliferation in embryonic and cancer cells. PKM2 has a novel function as protein kinase and transcription factor. In nucleus, PKM2 has a variety of binding proteins to regulate the expression of specific genes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Daytime radiative coolers are used to pump excess heat from a target object into a cold exterior space without energy consumption. Radiative coolers have become attractive cooling options. In this ...study, a daytime radiative cooler was designed to have a selective emissive property of electromagnetic waves in the atmospheric transparency window of 8–13 μm and preserve low solar absorption for enhancing radiative cooling performance. The proposed daytime radiative cooler has a simple multilayer structure of inorganic materials, namely, Al2O3, Si3N4, and SiO2, and exhibits high emission in the 8–13 μm region. Through a particle swarm optimization method, which is based on an evolutionary algorithm, the stacking sequence and thickness of each layer were optimized to maximize emissions in the 8–13 μm region and minimize the cooling temperature. The average value of emissivity of the fabricated inorganic radiative cooler in the 8–13 μm range was 87%, and its average absorptivity in the solar spectral region (0.3–2.5 μm) was 5.2%. The fabricated inorganic radiative cooler was experimentally applied for daytime radiative cooling. The inorganic radiative cooler can reduce the temperature by up to 8.2 °C compared to the inner ambient temperature during the daytime under direct sunlight.
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IJS, KILJ, NUK, PNG, UL, UM
Recently, the direct-absorption parabolic-trough solar collector (DAPTSC) using nanofluid has been proposed, and its thermal efficiency has been reported to be 5–10% point higher than the ...conventional surface-based parabolic-trough solar collector (SBPTSC). However, the inner tubes of the receivers of the existing DAPTSCs are all transparent such that sun rays entering the inner tube can only travel once through the nanofluid. Due to the approximately linear relationship between the absorption coefficient and the particle concentration, a higher absorption coefficient is likely to cause particle agglomeration, having detrimental effects on efforts to maintain stable collector performance. In the current study, the transparent DAPTSC is improved by applying a reflective coating on the upper half of the inner glass tube outer surface such that the optical path length is doubled compared to that of the transparent DAPTSC. This allows a reduction in the absorption coefficient of the nanofluid. The coated DAPTSC is found to have an obvious advantage compared to the transparent DAPTSC at absorption coefficients below 0.5 cm−1 for a receiver with an inner glass tube diameter of 7 cm.
•The proposed coated DAPTSC doubles optical path length and reduces radiation heat loss.•And has higher efficiency than the transparent DAPTSC at the same absorption coefficient.•Direct-absorption collector works better at larger diameter and lower flow rate.•Best configuration among the collectors largely depends on the inlet temperature.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Corrosion behavior of additively manufactured (AM) Ti–6Al–4V was examined.•Effect of the adsorption of Br− and Cl− ions on pitting corrosion was investigated.•Competitive adsorption of anions on ...pitting was simulated by Langmuir isotherm.•The relationship between the pitting, the doping densities and α′ phase was established.
Herein, the corrosion behavior of the additively manufactured (AM) Ti–6Al–4V is investigated based on the relation between the pitting potentials and equilibrium adsorption of the Br− and Cl− anions using potentiodynamic polarization curves, Mott–Schottky plots, and the Langmuir isotherm model. The Mott–Schottky plots are measured using the microdroplet cell technique based on the capacitance of the passive films on each dark and bright AM Ti–6Al–4V grain. The pitting potential can be attributed to the doping densities as well as α′ phase distribution and predicted using the equilibrium adsorption coefficient of Br− and Cl−.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Several experiments have shown a huge enhancement in thermal radiation over the blackbody limit when two objects are separated by nanoscale gaps. Although those measurements only demonstrated ...enhanced radiation between homogeneous materials, theoretical studies now focus on controlling the near-field radiation by tuning surface polaritons supported in nanomaterials. Here, we experimentally demonstrate near-field thermal radiation between metallo-dielectric multilayers at nanoscale gaps. Significant enhancement in heat transfer is achieved due to the coupling of surface plasmon polaritons (SPPs) supported at multiple metal-dielectric interfaces. This enables the metallo-dielectric multilayers at a 160-nm vacuum gap to have the same heat transfer rate as that between semi-infinite metal surfaces separated by only 75 nm. We also demonstrate that near-field thermal radiation can be readily tuned by modifying the resonance condition of coupled SPPs. This study will provide a new direction for exploiting surface-polariton-mediated near-field thermal radiation between planar structures.
•Systematic optimization is conducted for a direct absorption solar collector.•Absorption coefficient of the plasmonic nanofluid is taken as an optimization variable.•Thermal efficiency and ...temperature gain are taken as the performance indicator.•Lowest absorption coefficient is explored with satisfactory collector performance.
Recently, there have been grown interests in improving the performance of a direct absorption solar collector (DASC). The present work reports a systematic optimization to further improve the performance of a DASC, especially for a system using plasmonic nanofluids. Plasmonic nanofluids has adaptable absorption characteristics such that its absorption coefficient can be controlled to be nearly constant with respect to the wavelength by mixing different shapes (or sizes) of metallic nanoparticles. At the same time, the magnitude of the absorption coefficient can also be changed by varying the particle concentration. Therefore, the absorption coefficient of plasmonic nanofluids should be taken into account in the optimization processes; however, it has not drawn much attention in existing studies so far. In the present work, the collector geometry (i.e., depth and length of the channel), flow characteristics (i.e., flow rate), and fluid property (i.e., absorption coefficient) are taken as design variables in the optimization process. Effects of each variable on the temperature gain, thermal efficiency, and thermal loss parameter are theoretically analyzed. In order to reduce the cost of a DASC and avoid particle agglomeration when using plasmonic nanofluids, we also explore the configuration with the lowest possible absorption coefficient but with the reasonably high temperature gain as well as efficiency. The results of this study will facilitate the development of highly efficient solar thermal collectors using plasmonic nanofluids.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Our understanding of the gut microbiota of animals is largely based on studies of mammals. To better understand the evolutionary basis of symbiotic relationships between animal hosts and indigenous ...microbes, it is necessary to investigate the gut microbiota of non-mammalian vertebrate species. In particular, fish have the highest species diversity among groups of vertebrates, with approximately 33,000 species. In this study, we comprehensively characterized gut bacterial communities in fish.
We analyzed 227 individual fish representing 14 orders, 42 families, 79 genera, and 85 species. The fish gut microbiota was dominated by Proteobacteria (51.7%) and Firmicutes (13.5%), different from the dominant taxa reported in terrestrial vertebrates (Firmicutes and Bacteroidetes). The gut microbial community in fish was more strongly shaped by host habitat than by host taxonomy or trophic level. Using a machine learning approach trained on the microbial community composition or predicted functional profiles, we found that the host habitat exhibited the highest classification accuracy. Principal coordinate analysis revealed that the gut bacterial community of fish differs significantly from those of other vertebrate classes (reptiles, birds, and mammals).
Collectively, these data provide a reference for future studies of the gut microbiome of aquatic animals as well as insights into the relationship between fish and their gut bacteria, including the key role of host habitat and the distinct compositions in comparison with those of mammals, reptiles, and birds. Video Abstract.
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