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Theoretical analysis of seawater depth and temperature measurement with C-type micro-structured fiber grating
摘要： A new C-type micro-structured grating structure was proposed for simultaneous measurement of depth and temperature in seawater. Because wedge-shaped defects got introduce, high birefringence was excited at fiber core of grating. Thermo sensitive materials filled in micro pores to improve the sensitivity of temperature. Then we established a mathematical model of birefringence effect in C-type structure. This work analyzed stress distribution in all directions under two disturbances. In pressure and temperature environment, reflection peaks in two-polarization states separated with a large offset. Two characteristic parameters:λB, y ? λB, x, λB, y + λB, x were proposed for corresponding measurement. Structural parameters got optimize for better performance. Calculated output signals had high sensitivity and linearity under pressure range of 0–10 MPa and temperature range of 0–40 °C. λB, y ? λB, x mainly responded to pressure, which got sensitivity ?1.709 nm/MPa. While temperature mainly influenced λB, y + λB, x and the obtained temperature sensitivity was 1.054 nm/°C. This structure would have a great potential application due to the mature demodulation technique of grating signal.
关键词： Seawater measurement,Depth measurement,Temperature sensor,C-type micro-structured grating,Optical fiber sensor
更新于2025-09-23 15:22:29
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Oxygen-Defected Molybdenum Oxides Hierarchical Nanostructure Constructed by Atomic-Level Thickness Nanosheets as an Efficient Absorber for Solar Steam Generation
摘要： Solar steam generation is a potential approach for fresh water recycling, thus attracting increasing attention recently. To further promote water evaporation rate, some new materials need to be developed, such as plasmonic transition metal oxides. In this work, we report an oxygen-defected molybdenum oxides hierarchical nanostructure (MoOx HNS) composed of ultrathin nanosheets with atomic-level thickness, which is demonstrated as an efficient absorber for solar steam generation. Benefiting from broadband light absorption and special assembled architecture, the resulting MoOx HNS loaded on a PTFE membrane (MoOx HNS Membrane) exhibits excellent performance for boosting steam generation rate. Under 1 sun (1 kW m?2) illumination, the evaporation rate can reach at 1.255 kg m?2 h?1, with the energy conversion efficiency of 85.6%, which is one of the best performance compared with other desalination materials. Meanwhile, the MoOx HNS Membrane can achieve high-performance seawater desalination in both laboratorial and outdoor conditions. The enhanced water evaporation performance can be attributed to the synergistic effects of the efficient solar-to-thermal conversion and the unique channel structure. This work expands the scope of investigated materials which can be applied in seawater desalination system.
关键词： MoOx hierarchical nanostructure,seawater desalination,photothermal conversion,oxygen vacancies,solar steam generation
更新于2025-09-23 15:21:21
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Geometrical Properties of Spilled Oil on Seawater Detected Using a LiDAR Sensor
摘要： We report on a small-size light detection and ranging (LiDAR) sensor, which offers the possibility of being used in the field during oil spill incidents. In the present study, we develop an algorithm that can distinguish between seawater and oil through the use of a laser at 905 nm wavelength. We investigate the ability of the sensor to detect three different oil types (light crude, bunker A, and bunker C) through experiments and analyze the differences between the types and volumes of spilled oil (1, 5, 10, 15, 20, 25, 30, 35, 40, and 50 mL). The results showed that our algorithm for detecting oil spills over seawater was successful: the LiDAR sensor was able to detect different oil types and volumes. Spilled oil area coverage ranged by more than 50% of the detected area, and the viscosity of bunker C oil reached up to 73%. In addition, the experimental oil spills were mainly formed of oil films of 1 mm and 2 mm thicknesses, which confirmed geometrical properties. Follow-up research should further investigate the characteristics of oil slick thickness measured by the LiDAR system and undertake field tests to assess the feasibility of using the LiDAR system in pollution incidents.
关键词： LiDAR,algorithm,oil spill detection,oil thickness,seawater
更新于2025-09-23 15:21:01
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Photothermal response of plasmonic nanofillers for membrane distillation
摘要： Light-to-heat conversion in plasmonic nanoparticles (NPs) inside polymeric membranes is beneficial for improving the efficiency of membrane distillation for seawater desalination. However, the physical mechanisms ruling photothermal membrane distillation are unclear yet. Here, we model the plasmonic photothermal light-to-heat conversion from Ag, Au, and Cu nanofillers in polymeric membranes for membrane distillation. Photothermal effects in the cases of isolated metallic NPs and their assembly are investigated considering size effects and excitation sources. The increasing content of metallic NPs improves the efficiency of the light-to-heat conversion. For a polymeric membrane, filled with 25% Ag NPs, our model well reproduces the experimental temperature increase of 10 K. Specifically, we find that Ag NPs with a radius of around 30–40 nm are favorite candidates for membrane heating with excitation energy in the visible/near-UV range. The incorporation of a term associated with heat losses into the heat transfer equation well reproduces the cooling effect associated with vaporization at the membrane surface. Compared to Ag NPs, Au and Cu NPs show a broadened absorption cross section and their resonance has a nonlinear behavior with varying the excitation energy, better matching with sunlight radiation spectrum.
关键词： photothermal conversion,membrane distillation,seawater desalination,plasmonic nanoparticles,light-to-heat conversion
更新于2025-09-23 15:19:57
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Automated spectrophotometric determination of carbonate ion concentration in seawater using a portable syringe pump based analyzer
摘要： Observations of seawater carbonate ion concentrations are critical to assess the ecological effects of ocean acidification. Nevertheless, currently available methods are labor intensive or too complex for field applications. Here, we report the design and performance of the first fully automated portable carbonate ion analyzer. Measurements are based on reaction of carbonate and chloride ions with Pb(II) followed by quantitative UV spectrophotometric detection of the PbCO3 0 complex. The core hardware is a syringe pump equipped with a multi-position valve that is controlled by software written in LabVIEW. Measurement precision is 1.1% (n=13) with a measurement frequency of 12 h-1. The analyzer was used to continuously monitor carbonate ion concentration variations in a 2500 L coral reef tank for five days (test 1), and used for shipboard underway and vertical profile analysis during a 13-day cruise (test 2). The analyzer attained a combined standard uncertainty of 3.0%, which meets the Global Ocean Acidification Observing Network’s “weather level” goal. Through use of a syringe pump mechanism for mixing seawater and reagent solution, the analyzer is robust, functionally flexible, and quite suitable for continuous environmental monitoring under harsh conditions.
关键词： underway analysis,automated flow analysis,Seawater,coral reef,spectrophotometric detection,carbonate ion
更新于2025-09-19 17:15:36
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Plasmon Ag Promoted Solar-Thermal Conversion on Floating Carbon Cloth for Seawater Desalination and Sewage Disposal
摘要： Using solar energy to achieve seawater desalination and sewage disposal has received tremendous attention for its potential possibility to produce clean freshwater. However, the low solar-thermal conversion efficiency for solar absorber materials obstacles their practical applications. Herein, Ag nanoparticles (NPs) modified floating carbon cloth (ANCC) are firstly synthesized via wet-impregnation, photoreduction and low temperature drying strategy, which could float on the water and absorb the solar energy efficiently. It is worth noting that vaporization rate of ANCC with a high wide-spectrum absorption (92.39%) for the entire range of optical spectrum (200 - 2500 nm) is up to 1.36 kg h-1 m-2 under AM 1.5, which corresponds to solar-thermal conversion efficiency of ~92.82% with superior seawater desalination and sewage disposal performance. Plasmon Ag promotes the conversion efficiency obviously compared to the pristine carbon cloth because the surface plasmon resonance (SPR) effect could increase the local temperature greatly. After the desalination, the ion concentrations (Mg2+, K+, Ca2+ and Na+ ions) in water are far below the limit of drinking water. Such high-performance floating ANCC material may offer a feasible and paradigm strategy to manage the global water contamination and freshwater shortage problem.
关键词： seawater desalination,surface plasmon resonance,plasmon Ag,Solar-thermal energy conversion,floating carbon cloth
更新于2025-09-19 17:15:36
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Anomalous Light Scattering by Pure Seawater
摘要： The latest model for light scattering by pure seawater was used to investigate the anomalous behavior of pure water. The results showed that water exhibits a minimum scattering at 24.6 ?C, as compared to the previously reported values of minimum scattering at 22 ?C or maximum scattering at 15 ?C. The temperature corresponding to the minimum scattering also increases with the salinity, reaching 27.5 ?C for S = 40 psu.
关键词： light scattering by pure water,light scattering by pure seawater,light scattering,anomalous properties of water
更新于2025-09-19 17:15:36
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Sunlight-induced photocatalytic degradation of acetaminophen over efficient carbon doped TiO2 (CTiO2) nanoparticles
摘要： Carbon doped titanium oxide (CTiO2) photocatalyst was successfully synthesized by the sol–gel method. The crystal structure, surface morphology, and optical properties of CTiO2 have been characterized by X-ray diffraction, Brunauer–Emmett–Teller surface area (SBET), scanning electron microscope, UV–Vis, X-ray spectroscopy (EDS), Fourier transform infrared and X-ray photoelectron spectroscopy. The photocatalytic degradation of acetaminophen (AMP) in aqueous solution, seawater, and polluted seawater has been investigated by using the synthesized photocatalyst under irradiation of UV and natural sunlight. The effectiveness of CTiO2 compared to pure TiO2 toward the photocatalytic removal of AMP was significantly observed. The optimized conditions including catalyst dose, initial concentration of AMP and solution pH were also studied for effective photocatalytic removal. The highest degradation rate was obtained when 2.0 g L?1 of the catalyst was used at pH 7. The kinetic results revealed that the photocatalytic degradation of AMP using CTiO2 obeyed a pseudo-first-order reaction kinetics.
关键词： Photocatalytic degradation,Seawater,CTiO2,Nanoparticles,Acetaminophen,Sunlight
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN) - Fukuoka, Japan (2019.5.26-2019.5.29)] 2019 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN) - Optical sensor array based on P(V) corroles for fluorometric detection of nitrite
摘要： Two [5,10,15-pentafluorophenyl corrole] phosphorous (V), (PFCorr), and [10-(4-trimhetylsilyphenyl)-5,15-dimesityl-corrole] phosphorous (V) (PCorr) were synthesized and tested as nitrite-sensitive ionophore. Fluorimetry studies on ligand sensitivity towards anions were carried out first in solution and then inside polymeric membrane optodes. The selective ligand fluorescence quenching was registered upon addition of --ions. The influence on the PFCorr optode response of the lipophilic sites functionalization was investigated. The sensor will be tested in natural (fresh and seawater) and fish farm waters in order to detect the effectiveness of nitrite assessment at recommended concentrations levels (less than 0.3 mg/L).
关键词： phosphorous(V) corrole ligands,natural (fresh and seawater) and fish farm waters analysis,nitrite fluorometric assessment
更新于2025-09-16 10:30:52
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Nanocrystalline ZnO doped lanthanide oxide: An efficient photocatalyst for the degradation of diesel pollutant in seawater under visible light irradiation
摘要： In this study, a ZnO doped Er2O3 photocatalyst is employed to degrade diesel pollutant in seawater under visible light irradiation. The photocatalyst was prepared by a precipitation method and was characterized by SEM and XRD analysis. The experimental results proved that the nanocrystalline photocatalysts were highly active in the visible region. The photocatalytic degradation efficiency of diesel was analysed by various experimental parameters namely dosage, doping ratio, initial concentration of diesel, pH value, concentration of H2O2 and illumination time. The degradation of diesel pollution in seawater was optimized by orthogonal experiment. According to the results, the removal rate of diesel is less than 30 % without any catalysts (only evaporation). The best effect exists when the dose of catalysts was 0.6 g/L, doping ratio of catalysts was 10%, initial concentration of diesel was 0.2 g/L, pH value was 8, concentration of H2O2 was 10 mg/L, illumination time was 1 h. The removal rate of diesel can reach 99.38 %. This study would make ZnO utilize sunlight more efficiently and accelerate the practical application of photocatalytic technology in organic pollutants treatment region.
关键词： visible light irradiation,photocatalyst,Er2O3,diesel pollutant,seawater,ZnO
更新于2025-09-09 09:28:46