Integration and Application of a Fiber-Optic Sensing System for Monitoring Debris Flows

This study presents an innovative fiber-optic sensing system for monitoring debris flows. The system mainly comprises an interrogator and four fiber Bragg grating accelerometers. The field tests show that signal-to-noise-ratio (SNR) of the fiber-optic sensor is 10 dB higher than that of a geophone. Following confirmation of the reliability of the proposed sensing system, the systems are deployed along the Ai-Yu-Zi and Chu-Shui Creeks in Nautou County, Taiwan, for monitoring debris flows. The four accelerometers are installed in series. The systems have detected several debris flows in 2012. The monitored data reveal that the frequency range of the acceleration of ground vibration is 10-150 Hz, which is the same as that of the velocity of ground vibration detected by a sensing system that includes geophones. Because the fiber-optic sensing system is more sensitive than the geophone system, the proposed fiber-optic sensing system is highly promising for use in monitoring natural disasters that generate ground vibrations.本研究藉由組合光纖光柵加速度計、解調儀、及其他相關元件，發展一套可偵測土 石流之光纖感測系統。現地測試結果顯示，與目前常用含地聲檢知器的土石流感測系統相較， 本系統所測得地表振動訊號之訊雜比比前者高10 dB。在測試系統量測效能後，將此系統分別 架設於南投縣信義鄉神木村之愛玉子溪及出水溪上。系統中採串連方式配置四個光纖加速度 計，並於2012 年監測到多場土石流。觀測結果顯示，光纖感測系統所測得土石流所造成地表 振動之加速度，與過去地聲檢知器所測得土石流地表振動速度，兩者頻率一樣，均為10–150 Hz。由於光纖光柵加速度計相較於地聲檢知器更為靈敏，因此，除了可應用於偵測土石流外， 也可應用於監測會產生地表振動的其他坡地災害，如：落石及山崩等

Taiwan Oscillation Network

The Taiwan Oscillation Network (TON) is a ground-based network to measure solar intensity oscillations to study the internal structure of the Sun. K-line full-disk images of 1000 pixels diameter are taken at a rate of one image per minute. Such data would provide information onp-modes withl as high as 1000. The TON will consist of six identical telescope systems at proper longitudes around the world. Three telescope systems have been installed at Teide Observatory (Tenerife), Huairou Solar Observing Station (near Beijing), and Big Bear Solar Observatory (California). The telescopes at these three sites have been taking data simultaneously since October of 1994. Anl – v diagram derived from 512 images is included to show the quality of the data

S-Scheme System of MoS₂/Co₃O₄ Nanocomposites for Enhanced Photocatalytic Hydrogen Evolution and Methyl Violet Dye Removal under Visible Light Irradiation

Photocatalytic hydrogen production joined with simultaneous organic compound removal is a potential but challenging approach for both environmental modification and reusable energy generation. In this study, we designed a nanocomposite method for the fabrication of MoS2/Co3O4 heterojunction with an extremely productive photocatalytic capability. The as-fabricated MoS2/Co3O4 nanocomposites displayed greatly enhanced the hydrogen production (3825 μmol/g/h) and methyl violet dye (MV) contaminant removal (apparent kinetic constant of 0.038 min−1) activity. The nanocomposites’ structures had a better specific surface area, numerous active sites, and enhanced the transport ability of charge carriers to promote the photocatalytic activity. The increase in Co3O4 improved the visible-light absorption efficiency and narrowed energy bandgap and served as a highway for charge carriers to facilitate the transfer and separation and inhibit the combination of photoinduced charge carriers. The migration route of the photoexcited charges, the formation pathway, and the function of various reactive oxygen species (such as O2− and •OH) are discussed. The optimized energy band structure and high electron transfer rate of the S-scheme heterojunction nanocomposite promotes the evolution of H2 and the removal of pollutants, which shows an excellent potential in a stable and efficient photocatalytic hydrogen evolution and environment remediation

Photocatalytic Degradation of Methyl Orange Dyes Using Green Synthesized MoS₂/Co₃O₄ Nanohybrids

In this work, a new binary MoS2/Co3O4 nanohybrids was successfully fabricated and the chemical structures, morphologies, electrochemical and optical characterizations were carried out. In addition, heterojunction nanoparticles present in S-scheme structures act as electron traps and promote light absorption capacity for the degradation of Methyl orange (MO) with visible-light activity. MoS2/Co3O4 nanohybrids suggested excellent photocatalytic performance compared to bare MoS2 and Co3O4, where 95.6% of MO was degraded within 170 min, respectively. The results also showed excellent stability and recyclability over five consecutive cycles, without noticeable changes in the nanocomposite structure. The boosted photocatalytic degradation and redox activities of MoS2/Co3O4 can be attributed to the created S-scheme heterostructure to facilitate the separation of and to delay recombination of photoinduced charge carriers. We believe that this strategy of exploiting nanohybrid photocatalysts has great potential in the field of environmental catalysis and diverse applications

WSSe Nanocomposites for Enhanced Photocatalytic Hydrogen Evolution and Methylene Blue Removal under Visible-Light Irradiation

In this study, a novel tungsten disulfide diselenide (WSSe) nanocomposite by a facile hydrothermal process with great capable photocatalytic efficiency for hydrogen evolution from water and organic compound removal was discussed. The WSSe nanocomposites form heterojunctions in order to inhibit the quick recombination rate of photo-induced electrons and holes. This is considered to be a useful method in order to enhance the capability of photocatalytic hydrogen production. The hydrogen production rate of the WSSe nanocomposites approaches 3647.4 μmol/g/h, which is 12 and 11 folds the rates of the bare WS2 and WSe2, respectively. Moreover, the excellent photocatalytic performance for Methylene blue (MB) removal (88%) was 2.5 and 1.8 times higher than those of the bare WS2 and WSe2, respectively. The great photocatalytic efficiency was owing to the capable electrons and holes separation of WSSe and the construction of the heterostructure, which possessed vigorous photocatalytic oxidation and reduction potentials. The novel one-dimensional structure of the WSSe heterojunction shortens the transport pathway of the photo-induced electrons and holes. It possesses the great capable photocatalytic efficiency of the hydrogen production and organic dye removal. This study offers an insight into the route of interfacial migration and separation for induced charge carriers in order to generate clean hydrogen energy and to solve the issue of environmental pollution

Fiber-Optic Probe Array for Measuring Spatial Distributions of Air Volume Fractions in Bubbly Flows

In this study, we developed a fiber-optic sensing system with an eight-probe array for measuring the spatial distributions of air volume (void) fractions in bubbly flows. Initially, we performed calibration experiments in a cylindrical tank by using a fiber-optic sensing system with a single probe to determine the relationship between the time fraction ratio of bubble signals and void fractions. A high correlation coefficient was obtained between the time fraction ratio and the void fraction, suggesting that the proposed fiber-optic sensing system can measure local void fractions of up to 18%. Subsequently, we used the proposed fiber-optic sensing system with the eight-probe array to measure the spatial distribution of air volume fractions in a bubbly flow caused by breaking waves near a submerged breakwater. The effects of different variables, including the incident wave height, period, and width of the breakwater, on the spatial distribution of the void fraction on the lee side of the breakwater were systematically studied. The results demonstrated that the proposed fiber-optic sensing system can be used to determine the spatial distribution of air volume fractions in bubbly flows

Fabrication of WS2/WSe2 Z-Scheme Nano-Heterostructure for Efficient Photocatalytic Hydrogen Production and Removal of Congo Red under Visible Light

In this study, a novel tungsten disulfide/tungsten diselenide (WS2/WSe2) heterojunction photocatalyst by a facile hydrothermal process with great capable photocatalytic efficiency for hydrogen evolution from water and organic compound removal was discussed. The WS2/WSe2 heterojunction photocatalyst to form heterojunctions to inhibit the quick recombination rate of photo-response holes and electrons is reflected to be a useful method to enhance the capability of photocatalysis hydrogen production. The hydrogen production rate of the WS2/WSe2 photocatalyst approach is 3856.7 μmol/g/h, which is 12 and 11 folds the efficiency of bare WS2 and WSe2, respectively. Moreover, the excellent photocatalytic performance for Congo Red (CR) removal (92.4%) was 2.4 and 2.1 times higher than those of bare WS2 and WSe2, respectively. The great photocatalytic efficiency was owing to the capable electrons and holes separation of WS2/WSe2 and the construction of Z-scheme heterostructure, which possessed vigorous photocatalytic oxidation and reduction potentials. The novel one-dimensional structure of WS2/WSe2 heterojunction shortens the transport pathway of photo-induced electrons and holes. This work provided an insight to the pathway of interfacial separation and transferring for induced charge carriers, which can refer to the interfacial engineering of developed nanocomposite photocatalysts. It possessed great capable photocatalytic efficiency of hydrogen production and organic dye removal. This study offers an insight to the route of interfacial migration and separation for induced charge carriers to generating clean hydrogen energy and solve environmental pollution issue

Fiber-Optic Probe Array for Measuring Spatial Distributions of Air Volume Fractions in Bubbly Flows

In this study, we developed a fiber-optic sensing system with an eight-probe array for measuring the spatial distributions of air volume (void) fractions in bubbly flows. Initially, we performed calibration experiments in a cylindrical tank by using a fiber-optic sensing system with a single probe to determine the relationship between the time fraction ratio of bubble signals and void fractions. A high correlation coefficient was obtained between the time fraction ratio and the void fraction, suggesting that the proposed fiber-optic sensing system can measure local void fractions of up to 18%. Subsequently, we used the proposed fiber-optic sensing system with the eight-probe array to measure the spatial distribution of air volume fractions in a bubbly flow caused by breaking waves near a submerged breakwater. The effects of different variables, including the incident wave height, period, and width of the breakwater, on the spatial distribution of the void fraction on the lee side of the breakwater were systematically studied. The results demonstrated that the proposed fiber-optic sensing system can be used to determine the spatial distribution of air volume fractions in bubbly flows

Calibration and Deployment of a Fiber-Optic Sensing System for Monitoring Debris Flows

sensor