A comparison between simulation and experimental results for depth profile of 6Li reaction rate in a water phantom of BNCT using a small 6Li-based scintillator neutron detector with an optical fiber

Calcium oxide/Calcium hydroxide can be utilized as a reaction system for thermochemical heat storage. It features a high storage capacity, is cheap, and does not involve major environmental concerns. Operationally, different fixed-bed reactor concepts can be distinguished; direct reactor are characterized by gas flow through the reactive bulk material, while in indirect reactors, the heat-carrying gas flow is separated from the bulk material. This study puts a focus on the indirectly operated fixed-bed reactor setup. The fluxes of the reaction fluid and the heat-carrying flow are decoupled in order to overcome limitations due to heat conduction in the reactive bulk material. The fixed bed represents a porous medium where Darcy-type flow conditions can be assumed. Here, a numerical model for such a reactor concept is presented, which has been implemented in the software DuMux. An attempt to calibrate and validate it with experimental results from the literature is discussed in detail. This allows for the identification of a deficient insulation of the experimental setup. Accordingly, heat-loss mechanisms are included in the model. However, it can be shown that heat losses alone are not sufficient to explain the experimental results. It is evident that another effect plays a role here. Using Bayesian inference, this effect is identified as the reaction rate decreasing with progressing conversion of reactive material. The calibrated model reveals that more heat is lost over the reactor surface than transported in the heat transfer channel, which causes a considerable speed-up of the discharge reaction. An observed deceleration of the reaction rate at progressed conversion is attributed to the presence of agglomerates of the bulk material in the fixed bed. This retardation is represented phenomenologically by mofifying the reaction kinetics. After the calibration, the model is validated with a second set of experimental results. To speed up the calculations for the calibration, the numerical model is replaced by a surrogate model based on Polynomial Chaos Expansion and Principal Component Analysis.

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Multiple Light Coupling and Routing via a Microspherical Resonator Integrated in a T-Shaped Optical Fiber Configuration System

Micromachines ◽

10.3390/mi9100521 ◽

2018 ◽

Vol 9 (10) ◽

pp. 521 ◽

Cited By ~ 2

Author(s):

Georgia Konstantinou ◽

Karolina Milenko ◽

Kyriaki Kosma ◽

Stavros Pissadakis

Keyword(s):

Optical Fiber ◽

Optical Fibers ◽

Single Mode ◽

Equatorial Region ◽

Experimental Results ◽

Glass Microsphere ◽

Single Mode Optical Fiber ◽

Light Coupling ◽

Fiber Taper ◽

Optical Fiber Taper

We demonstrate a three-port, light guiding and routing T-shaped configuration based on the combination of whispering gallery modes (WGMs) and micro-structured optical fibers (MOFs). This system includes a single mode optical fiber taper (SOFT), a slightly tapered MOF and a BaTiO3 microsphere for efficient light coupling and routing between these two optical fibers. The BaTiO3 glass microsphere is semi-immersed into one of the hollow capillaries of the MOF taper, while the single mode optical fiber taper is placed perpendicularly to the latter and in contact with the equatorial region of the microsphere. Experimental results are presented for different excitation and reading conditions through the WGM microspherical resonator, namely, through single mode optical fiber taper or the MOF. The experimental results indicate that light coupling between the MOF and the single mode optical fiber taper is facilitated at specific wavelengths, supported by the light localization characteristics of the BaTiO3 glass microsphere, with spectral Q-factors varying between 4.5 × 103 and 6.1 × 103, depending on the port and parity excitation.

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Photoreduction of Cr(VI) Ions in Aqueous Solutions by UV/ Photocatalytic Processes

International Journal of Photoenergy ◽

10.1155/2012/381971 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Chih Ming Ma ◽

Yung Shuen Shen ◽

Po Hsiang Lin

Keyword(s):

Aqueous Solutions ◽

Reaction Rate ◽

Removal Rate ◽

Experimental Results ◽

Order Kinetic ◽

Solution Ph ◽

Relationship Of ◽

The Relationship ◽

Photocatalytic Processes ◽

Order Kinetic Equation

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.

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Experimental results on embedded optical fiber sensors in concrete

10.1117/12.147999 ◽

1993 ◽

Cited By ~ 1

Author(s):

Alexis Mendez ◽

Theodore F. Morse ◽

Lawrence J. Reinhart

Keyword(s):

Optical Fiber ◽

Optical Fiber Sensors ◽

Experimental Results ◽

Fiber Sensors

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Re-evaluation of the glycerol-3-phosphate dehydrogenase/l-lactate dehydrogenase enzyme system. Evidence against the direct transfer of NADH between active sites

Biochemical Journal ◽

10.1042/bj2780875 ◽

1991 ◽

Vol 278 (3) ◽

pp. 875-881 ◽

Cited By ~ 6

Author(s):

S P J Brooks ◽

K B Storey

Keyword(s):

Lactate Dehydrogenase ◽

Active Sites ◽

Reaction Rate ◽

Experimental Results ◽

Transfer Model ◽

Rabbit Muscle ◽

Direct Transfer ◽

Theoretical Predictions ◽

Glycerol 3 Phosphate Dehydrogenase

An investigation of the direct transfer of metabolites from rabbit muscle L-lactate dehydrogenase (LDH, EC 1.1.1.27) to glycerol-3-phosphate dehydrogenase (GPDH, EC 1.1.1.8) revealed discrepancies between theoretical predictions and experimental results. Measurements of the GPDH reaction rate at a fixed NADH concentration and in the presence of increasing LDH concentrations gave experimental results similar to those previously obtained by Srivastava, Smolen, Betts, Fukushima, Spivey & Bernhard [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 6464-6468]. However, a mathematical solution of the direct-transfer-mechanism equations as described by Srivastava et al. (1989) showed that the direct-transfer model did not adequately describe the experimental behaviour of the reaction rate at increasing LDH concentrations. In addition, experiments designed to measure the formation of an LDH4.NADH.GPDH2 complex, predicted by the direct-transfer model, indicated that no significant formation of tertiary complex occurred. An examination of other kinetic models, developed to describe the LDH/GPDH/NADH system better, revealed that the experimental results may be best explained by assuming that free NADH, and not E1.NADH, is the sole substrate for GPDH. These results suggest that direct transfer of NADH between rabbit muscle LDH and GPDH does not occur in vitro.

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Advanced oxidation of methyl tert-butyl ether (MTBE) by UV/TiO2 and H2O2-UV/TiO2 processes

Water Science & Technology Water Supply ◽

10.2166/ws.2006.053 ◽

2006 ◽

Vol 6 (2) ◽

pp. 77-85 ◽

Cited By ~ 1

Author(s):

C.-H. Hung

Keyword(s):

Light Intensity ◽

Degradation Rate ◽

Reaction Rate ◽

Experimental Results ◽

Methyl Tert Butyl Ether ◽

H2o2 Concentration ◽

Pseudo First Order Reaction ◽

Butyl Ether ◽

Solution Ph ◽

Degradation Rates

This study investigated photocatalysis of MTBE via both UV/TiO2 and H2O2-UV/TiO2 processes. Several experimental parameters including pH level, H2O2 concentration, TiO2 dosage and light intensity were investigated. The experimental results demonstrated the degradation of MTBE following a pseudo first-order reaction in both reaction systems. Faster degradation rates were observed in alkaline solution for the UV/TiO2 system, but for the H2O2-UV/TiO2 system, faster degradation rates were detected in acidic solution. More dosage of TiO2 and irradiated light intensity were beneficial for the photocatalysis of MTBE. However, a peak reaction rate was observed at a TiO2 concentration of about 500 mg/L. The experimental results also indicated that the degradation rate of MTBE was enhanced by the addition of H2O2. H2O2 could be a more efficient electron acceptor than oxygen for retarding recombination of electron–hole pairs. The degradation rate in the H2O2-UV/TiO2 system was about 2.8 times faster than that in the UV/TiO2 system for solution pH below 5, and the rate increased 30% for solution pH above 6. In addition, it is observed that the reaction rate of MTBE increased quickly with H2O2 concentration at low H2O2 dosages, but the rate was independent of H2O2 dosage when adding too much H2O2.

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Accelerated Cooling of Optical Fiber

MRS Proceedings ◽

10.1557/proc-172-49 ◽

1989 ◽

Vol 172 ◽

Cited By ~ 2

Author(s):

S. Kyriacou ◽

C. E. Polymeropoulos ◽

V. Sernas

Keyword(s):

Optical Fiber ◽

Gas Flow ◽

Small Diameter ◽

Experimental Results ◽

Accelerated Cooling ◽

Fiber Motion

AbstractA novel apparatus for accelerated cooling of optical fiber has been used at different fiber speeds using Nitrogen and Helium as the cooling gases. The gas flow was counter to the direction of the fiber motion inside a small diameter tube. The experimental results show significant improvement over natural cooling, as well as over available transverse cooling.

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Coating Nano-TiO2 on Optical Fiber with Al(H2PO4)3 Adhesive

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.280-283.485 ◽

2007 ◽

Vol 280-283 ◽

pp. 485-488 ◽

Cited By ~ 1

Author(s):

Yu Hong Zhao ◽

Jia Chen Liu ◽

Shun Li ◽

Yi Rong Liu

Keyword(s):

Optical Fiber ◽

Process Parameters ◽

Coating Thickness ◽

Fiber Surface ◽

Tio2 Coating ◽

Experimental Results ◽

Coating Process ◽

High Quality ◽

Tio2 Photocatalysis

To meet the need of optical fiber photoreactor designed by mechanism of TiO2 photocatalysis, nanometer TiO2 was coated on the surface of optical fiber by dipping nude fibers into an Al(H2PO4)3-contained TiO2 slurry. Effects of slurry conditions, including content of TiO2 and addition of Al(H2PO4)3 adhesive, on coating thickness and quality were determined. Coating process, especially the effect of coating times, was also concerned. Based on the experimental results, fitting slurry conditions and process parameters were suggested for obtaining high-quality TiO2 coating on optical fiber surface.

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