Solar energy-to-heat conversion for steam generation is an essential metrology for power generation, water purification and desalination. Harvesting light energy and converting it to heat as terminal ...energy by black photothermal sheets is a novel strategy to attain this goal. This technology rely on use of black nanomaterials as light absorber to increase the absorption and conversion efficiency of solar energy. Fundamental understanding of their structure-property has to be fully exploited for further developing efficient solar-to-heat systems. This report summarizes physical understanding and experimental advances in development of black photothermal sheets for solar water evaporation. We examine the popular photothermal systems with remarkable vapor generation performance to identify the state-of-the-art of the device design. Three groups of the photothermal sheet are discussed in terms of different light-harvesting materials, such as carbon-based sheets, plasmonic sheets as well as semiconducting sheets. The physical difference of these novel devices with their steam releasing property are also highlighted.
This report summarizes the physical understanding and experimental advances in development of black photothermal sheets for solar water evaporation, and illustrates their key features for high-efficiency steam generation. Display omitted
•Physics of black material for light-to-heat conversion.•The absorbers using various black materials are identified.•The state-of-the-art design of the photothermal sheets.•The devices with their steam releasing property are highlighted.
Although the biological basis of hepatocellular carcinoma (HCC) remains unclear, effective treatments and improvement of the survival rate remain worthwhile research goals. Abnormal protein signaling ...pathways contributing to uncontrolled cell proliferation, differentiation, survival and apoptosis are biomarkers of the carcinogenic process. Certain mutated components or overexpression of the rat sarcoma virus (Ras)/rapidly accelerated fibrosarcoma (Raf)/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway are increasingly being studied in HCC carcinogenesis. The present review addresses the effect of the Ras/Raf/MEK/ERK signaling pathway on the pathogenesis of HCC, and provides an update on the preclinical and clinical development of various inhibitors targeting this core signaling pathway, which include various Ras inhibitors, Raf inhibitors and MEK inhibitors for HCC.
Development of magnetic nanoparticles (MNPs) for use as supports and exploration of their applications in aqueous catalysis represent an important branch of green chemistry as they enable ...environmentally friendly and sustainable catalytic processes. Besides the significant merit of easily recovering magnetic nanoparticles from reaction systems, various strategies through surface modification, grafting and self-assembly offer a broad range of approaches for constructing magnetically recoverable heterogeneous catalysts. In this review, we focus on the green catalytic processes and summarize recent advances in organic transformations catalyzed by magnetically recoverable catalysts (MRCs). This paper is divided into two main parts: the first part provides background information on the general preparation, modifications, and characterization, where the modifications of various magnetic nanoparticles through coating with silica, carbon, metal, or polymer are also presented. The second part provides a basic outline of aqueous catalysis based on water-only or water-and-organic solvent cosolvent systems, in which numerous types of organic transformations are catalyzed by magnetically recoverable catalysts. Lastly, perspectives for further development of magnetically recoverable heterogeneous catalysts in aqueous catalysis are addressed.
This review focuses on the development of magnetically recoverable nanoparticles as efficient catalysts for organic transformations in aqueous media.
We study properties of the innermost photonsphere in the regular compact star background. We take the traceless energy–momentum tensor and dominant energy conditions. In the regular compact star ...background, we analytically obtain an upper bound on the radius of the innermost photonsphere as
r
γ
in
⩽
12
5
M
,
where
r
γ
in
is the radius of the innermost photonsphere and
M
is the total ADM mass of the asymptotically flat compact star spacetime.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Pathogen ingestion through drinking water bring about severe health threats to human beings. Recently innovative nanotechnology and their integrated systems provide new opportunities to address the ...challenges of solar water sterilization by killing pathogens. Of particular interest in this context, we aim to review the-state-of-art knowledge on solar water sterilization by use of photothermal nanomaterials to enhance the efficiency and affordability of water treatment. The basic principle of solar water sterilization is firstly described from the photothermal conversion and heat transfer physics to thermal sterilization mechanism. The engineering design of photothermal materials is then summarized from the aspects of light absorption, heat localization and other synergistic sterilization actions. The links between the photothermal properties of materials and their sterilization performance are highlighted by using solar energy. Furthermore, rationally orienting photothermal nanomaterials in reactor configurations including batch or continuous flow reactor and its crucial role in improving sterilization performance is analyzed depending on the reaction mechanism. Finally, the future challenges and prospects are outlined for further development of solar sterilization technology.
This work discusses physical understanding and engineering design of photothermal nanomaterials and reactors by use of solar energy for water sterilization. Display omitted
●Photothermal mechanism and heat transfer physics are revisited.●The basic principle of solar water sterilization is stressed.●The engineering design of photothermal materials is fully summarized.●Nanomaterials integrated in batch or continuous flow reactors are discussed.●Future challenges and prospects are highlighted for further development.
We investigate distributions of matter fields outside spherically symmetric ultra-compact objects with null circular orbits in the asymptotically flat background. Based on the dominant energy and the ...non-negative trace conditions, we prove the existence of effective radius of matter field hairs outside horizonless ultra-compact objects. We also analytically find a no long hair behavior, which states that the effective radius of matter field hairs cannot extend beyond the outermost null circular orbit of horizonless ultra-compact objects.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Shallow epikarst fissure soil (EFS) has good hydraulic connectivity.•Soil structure controls water infiltration and retention time in the epikarst.•Vertical hydraulic connectivity of EFS is ...different from surface soil.•The hydrological path of EFS in rocky desertification areas is complex.
Epikarst fissures filled with soil (EFS) are important factors controlling karst hydrological processes and ecological hydrological functions. The EFS are common in karst rocky desertification areas, and it is important to understand the hydraulic properties and hydrological characteristics of EFS for vegetation restoration. In this study, we analysed the soil moisture content dynamics of surface soil and EFS in a rocky desertification environment to explore the influencing factors of soil moisture variation. A typical epikarst fissure was selected as the sample site in the rocky desertification area of the Karst Plateau Gorge (Beipanjiang catchment, Guizhou Province) in Southwest China, and surface soil was used as the control site. From May 12, 2018 to January 10, 2020, soil moisture content data for the EFS profile (20, 80, 140, 200, and 260 cm) and the surface soil profile (20 and 40 cm) were monitored synchronously at 30-min intervals. Simultaneously, soil samples were collected to measure the physical properties. The results show that the difference in vegetation cover and soil physical properties is the main reason for the difference in soil water dynamics between the shallow EFS and surface soil. The shallow EFS hydraulic connectivity is better, and the mean values of total porosity and saturated hydraulic conductivity of shallow EFS are 15.6% and 69.5% higher than those of the surface soil, respectively. The seasonal variations in soil moisture in the shallow EFS are obvious, the soil moisture rainfall response and dry-wet alternation are fast, the seasonal variations in soil moisture in the surface soil are relatively stable, and the soil water retention time is long. In the EFS profile, the hydraulic connectivity of the shallow soil (0–40 cm) are obviously better than those in the middle and lower layers (40–280 cm), which affected the response speed and retention time of soil water at different depths. In conclusion, the vertical hydraulic connectivity of the EFS profile is quite different and is shown to be significantly different from the surface soil hydrology. These results are helpful for understanding the ecohydrological process of epikarst.
Surface wettability of TiO2 nanotube arrays prepared by electrochemical anodization.
•Controllable fabrication of highly ordered TNT films.•As-anodized TNTs are hydrophilic and annealing increases ...the wettability.•Hydrophilicity increased with increasing the diameter of TNTs.•The bottom surface of TNT membrane exhibits superhydrophilic.
This work reports structural engineering and wettability of titania nanotube arrays (TNTs). The nanotube diameter and thickness of TNT layer increase with increasing of applied voltage from 20 to 40, 60 and 80V, and the diameter has no relevance to extending anodic duration. The fabricated TNTs are 30–190nm inner diameter and 5–40mm height. 10mL water droplets are applied to define wettability of the TNTs by measuring contact angles. Hydrophilicity is enhanced with increasing diameter of TNTs as well as over-etching occurring on the surface. Large diameter tubes and capillary force provide more space and power for liquid to penetration. The contact angle reduces from 35° to 2° with the tube diameter increasing from 30 to 190nm. Bare Ti foil is inherently hydrophobic with approximately 90° contact angle. The as-prepared TNTs are hydrophilic with contact angle of 24°, and annealing further improves this property to a contact angle of 13°. The bottom of TNTs shows superhydrophilic due to hydroxide compounds existed on the surface. The metal substrate with tube footprint left presents hydrophobic with contact angle of 68°, which is lower than the bare one. It is believed that wettability on the surface of TNTs is dependent on their morphology and chemical composition.
The homogenized elastic properties and tensile fracture behaviours of concrete are captured by Monte Carlo simulations (MCSs) of realistic meso-scale models based on high-resolution micro-scale X-ray ...Computed Tomography (XCT) images, using asymptotic homogenization and the concrete damaged plasticity (CDP) model. The obtained realistic models are quite promising in characterising meso-scale mechanical behaviours of concrete. The statistical analysis shows that the intrinsic heterogeneity of meso-structures caused by random spatial distribution of multi-phases can significantly affect macroscopic responses of concrete, e.g. homogenized elastic properties, crack patterns and load-carrying capacities. Moreover, since the 3D model is built from 2D images by a bottom-up stacking algorithm, the resultant 3D model is strongly correlated to the 2D models in physical nature, thus the 2D-3D comparisons can yield more insightful views. The effects of aggregate/void area fraction on homogenized elastic modulus and tensile strength are also analysed.
We consider static scalar fields coupled to the gradient where the coupling also appears in next-to-leading order Ginzburg-Landau models. We study condensation behaviors of scalar fields outside ...regular compact reflecting stars in the asymptotically flat background. For non-negative coupling parameters, we prove that the reflecting star cannot support coupled static scalar fields.
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