Dual Optical Probe Research Articles

Dual Optical Measurement Probe System for Double-Sided Film Structure

Dual Optical Measurement Probe System for Double-Sided Film Structure

Synthesis of carbazole-based dendritic conjugated polymer: a dual channel optical probe for the detection of I− and Hg2+

ABSTRACT A new type of carbazole-based blue-emitting dendritic conjugated polymer, poly[(9,9-dioctyl)-2,7-fluorene-co-4,4’,4”-triphenylamine-co-9-(4-(9H-carbazol-9-yl)butyl)-3,6-carbazole](P), was successfully synthesized by Suzuki coupling reaction. Chemical structures of monomers and polymer were verified by FI-IR and 1HNMR characterizations. We found that polymer showed a special selectivity and high sensitivity for I−. With the addition of I−, the fluorescent polymer solution was obviously quenched. The polymer showed a special detection effect on I−. However, the fluorescent polymer was obviously restored when Hg2+ was added to the P/I− system due to the large complexation between I− and Hg2+. The anti-interference experiments of probe P/I− showed that other background cations have a slight influence on detecting Hg2+, and the calculated detection limit of Hg2+ reached 9.7 × 10−8 M, which could be a potential application for a two-channel cyclic detection of I− and Hg2+. Additionally, it was found that the theoretical values were in agreement with the experimental data.

Phase coexistence in fluidization

AbstractThe coexistence and interaction of a granular liquid‐like phase (emulsion) and a gas‐like phase (bubbles) in fluidization is a spontaneous symmetry‐breaking dissipative state, contributing to excellent mixing behavior in fluidized beds. In the present study, a universal granular state equation to describe the phase coexistence at far away from the critical point is developed by taking both the inelastic solid collision and asymmetrical instability into consideration. Besides, a cold‐flow experiment using particles of the Geldart's A group at 0.1–1 MPa pressure is performed to verify the granular state equation, where the solid volume fraction (εs) and solid pressure (ps) are obtained by a dual optical probe and a special pressure transducer, respectively. Based on both theoretical analysis and experimental study, a phase diagram is produced to serve as a useful guide for the design and operation of efficient fluidized‐bed reactors.

Dual magnetic field and temperature optical probes of controlled crystalline phases in lanthanide-doped multi-shell nanoparticles.

The engineering of core@multi-shell nanoparticles containing heterogeneous crystalline phases in different layers constitutes an important strategy for obtaining optical probes. The possibility of obtaining an opto-magnetic core@multi-shell nanoparticle capable of emitting in the visible and near-infrared ranges by upconversion and downshifting processes is highly desirable, especially when its optical responses are dependent on temperature and magnetic field variations. This work proposes the synthesis of hierarchically structured core@multi-shell nanoparticles of heterogeneous crystalline phases: a cubic core containing DyIII ions responsible for magnetic properties and optically active hexagonal shells, where ErIII, YbIII, and NdIII ions were distributed. This system shows at least three excitation energies located at different biological windows, and its emission intensities are sensitive to temperature and external magnetic field variations. The selected crystalline phases of the core@multi-shell nanoparticles obtained in this work is fundamental to the development of multifunctional materials with potential applications as temperature and magnetic field optical probes.

A dual optical probe with larger stokes shift for simultaneous detection of Cu2+ and Zn2+ ions and aggregation induced enhanced emission empowering selective detection of Cu2+ ions

A new aggregation induced enhanced emission (AIEE) active probe (1) has been synthesized via single step condensation reaction of 2-amino-3-benzyloxypyridine with 3-allylsalicylaldehyde in methanol. Probe 1 has been fully characterized by various spectroscopic techniques i.e. IR, NMR (1H and 13C), HRMS and X-ray crystallography. 1 displays a large stokes shift of 190 nm. It recognizes Cu2+ ions colorimetrically and fluorescence intensity enhances on the addition of Zn2+ ions. 1 form nanoaggregates in H2O:CH3OH (80:20, v/v) which detects Cu2+ ions selectively. 1 in the presence of Zn2+ ions and its nanoaggregates n1 show switch on behaviour of green fluorescence comparable to mitochondrial membrane potential indicator, Mitotracker-Red, in larval gut tissues of Drosophila melanogaster.

Highly Luminescent Thermoresponsive Green Emitting Gold Nanoclusters for Intracellular Nanothermometry and Cellular Imaging: A Dual Function Optical Probe.

In view of many promising applications of gold nanoclusters (AuNCs), nanothermometry is an important field of research in biology and medicine. Here, we demonstrate the temperature dependent photophysical properties of highly luminescent green emitting 6-aza-2-thiothymine/l-arginine-stabilized Au nanosclusters (ATT/Arg Au NCs) by using steady state and time-resolved photoluminescence spectroscopy. Significantly, thermoresponsive properties of these highly photostable and biocompatible Au NCs are reversible, which endow the probe for further bioanalytical applications with great prospects. Additionally, protein-NC interaction mechanism has been elucidated in vitro and in vivo that dictates the complex behavior of the NCs with living organisms. These ultrasmall Au NCs are observed to accumulate in the cellular cytoplasm by translocating through the membrane as evidenced from the confocal laser scanning microscopy (CLSM). In vivo temperature sensing examined with human osteosarcoma cell line (MG-63 cell) by employing fluorescence lifetime imaging microscopy (FLIM) technique reveals the optimistic application of these lifetime-based nanosensors in biomedicine and biotechnology.

A coumarin-based dual optical probe for homocysteine with rapid response time, high sensitivity and selectivity

In this study, a new coumarin-based fluorescent and chromogenic dual channel probe (DC) was used for the selective detection of homocysteine (Hcy) over other amino acids, especially for cysteine (Cys) and glutathione (GSH). When Hcy is present in the solution, the remarkable fluorescence enhancement and obvious blue shift in UV–vis spectra can be observed. In addition, the color change from purple to yellow can be observed clearly by unaided eyes. This probe DC has fast response time, excellent sensitivity and selectivity to Hcy. A linear relationship exists between the ratio of emissions at 486 and 625 nm, and Hcy can be detected in a wide concentration range (0–200 μM). The signal-to-background ratio of fluorescence at 486 nm can reach 8.4, and the detection limit is calculated to be 3.5 µM. The response mechanism is proved to be the Michael addition reaction by Hcy. Preliminary results on cell imaging enable the practical application of Hcy tracing in living cells.

An Optical Chemodosimeter Coumarin Nosylate for Probing Fluoride Ion: Synthesis, Crystal Structures, Photophysical and Theoretical Studies

AbstractTo achieve selectivity for fluoride recently researchers resorted on its nucleophilic characteristics rather than its basicity. The design strategy of this kind of probe involves masking of a fluorescent moiety with NBS/DNBS masking groups. Attack of fluoride over the same leads to release of fluorescent moiety in the solution. The prime concern of this family of probes is that no crystallographic evidence is available till date in the literature to the best of our knowledge. We are reporting herein a new chemodosimeter in the form of a coumarin nosylate (CMS) as a dual channel optical probe for the smart detection of fluoride. Interestingly, we not only isolated single crystals of CMS but also successfully isolated the fluoride (F−) induced cleaved product of CMS i. e. chromenolate counter balanced with tetrabutylammonium (TBA) ion.

Development of a dual optical fiber probe for the hydrodynamic investigation of a horizontal annular drive gas/liquid ejector

A dual-channel optical fiber probe was developed to quantify the bubble characteristics (void fraction, velocity, and bubble size) in a gas–liquid annular ejector system. Water is pumped upstream of the ejector contraction. Since a low pressure region exists downstream in the ejector diffuser, this permits air to be sucked into the flowing liquid by jet pump action and the inlet air volumetric flow rate is measured by a flow meter. Verification of the void fraction (range 0.15–0.5) measured by the optical fiber probe was then possible and deviations were generally around ± 5%. Also, bubble velocity was measured using the optical probe by cross-correlating signals from the two fibers whose tips are separated by a known distance. Alternatively measuring bubble velocity using a particle image velocimetry method provided validation for the optical fiber probe system where a high speed camera was used to capture instantaneous bubble images at time intervals of 0.125ms. Excellent agreement between the velocities using both methods is reported. For bubble size measurements, analyzing the temporal signals from a single probe enabled estimation of the size of a bubble. Bubble sizes measured ranged between 1.5 and 6.0mm and size distributions were constructed for different ejector water volumetric flow rates ranging from 0.0022 to 0.0063m3/s. LabVIEW provided a convenient platform for coding the algorithms for estimating the void fraction, bubble velocity and bubble size. For further comparison, a CFD study of the ejector system was done, and the vertical radial profiles of the void fraction were compared with those obtained by the optical fiber system and these showed good agreement.

Fused oxazolidine-based dual optical probe for galactosidase with a dramatic chromogenic and fluorescence turn-on effect

A dual optical probe based on a fused oxazolidinoindocyanine moiety was prepared for detection of β-galactosidase in the biological condition. The probe displayed both a dramatic colorless-to-red optical change and a fluorescence turn-on response in the visible region, exhibiting a high sensitivity for β-galactosidase with a very low limit of detection (LOD = 0.071 U/L) in neutral PBS buffer.

Indocyanine based dual optical probe for cyanide in HEPES buffer

A dual optical probe based on N-hydroxyethylindocyanine was prepared for the selective detection of cyanide in water. The probe exhibited a dramatic red-to-colorless optical change and a fluorescence on–off response in the visible region, displaying high selectivity toward cyanide over other various anions and Cys with a micromolar limit of detection (LOD = 2.0 μM) in an aqueous buffer. Furthermore, the probe underwent a reversible reaction with the probe-cyanide ion adduct in the presence of Hg(II), of which optical changes were easily detected by direct visualization.

Activatable colorimetric and fluorogenic probe for fluoride detection by oxazoloindole-to-hydroxyethylindolium transformation

An oxazoloindole-based dual optical probe displayed a highly sensitive response to fluoride with dramatic UV-vis and fluorescence changes in aqueous solution.

Effects of gold nanoparticles and fluoxetine on marine organisms

A dual optical probe based on a fused oxazolidinoindocyanine moiety was prepared for detection of β-galactosidase in the biological condition. The probe displayed both a dramatic colorless-to-red optical change and a fluorescence turn-on response in the visible region, exhibiting a high sensitivity for β-galactosidase with a very low limit of detection (LOD = 0.071 U/L) in neutral PBS buffer.

Effect of drops on turbulence of kerosene–water two-phase flow in vertical pipe

The effect of introducing kerosene drops on turbulence of kerosene–water two-phase in a vertical pipe is investigated experimentally. A hot-film and dual optical probes are used to measure the water velocity, turbulence fluctuation, drop relative velocity, volume fraction and drop diameter. Experiments are performed in a 78.8mm diameter vertical pipe for four average water velocities of 0.11, 0.29, 0.44 and 0.77m/s. The measurements were carried out for two area average volume fraction 〈α〉 of 4.6% and 9.2% as well as for water single phase flow to investigate the effect of introducing kerosene drops on two-phase flow turbulence. The kerosene–water mixture was generated by adding the kerosene to constant flow rates of water. The results indicate that drops induced turbulence is a function of the ratio of the drop Reynolds number (UrdB/ν) to the turbulence Reynolds number (u′Lt/ν) which decreased with higher water velocities. The results show that the Kolmogorov–Richardson scaling in the range of −4.5/3 to −6/3 for single phase flow which is replaced by −6/3 to −7/3 for two-phase flow. These values are less than −8/3 for air–water flow.

NaGdF4 Nanoparticles Coated with Functionalised Ethylenediaminetetraacetic Acid as Versatile Probes for Dual Optical and Magnetic Resonance Imaging.

NaGdF4 nanoparticles (NPs) coated with organic ligands are known to provide efficient "positive" contrast in magnetic resonance imaging (MRI). Strongly chelating ligands, such as ethylenediaminetetraacetic acid (EDTA) and d,l-1,2-diaminopropionic-N,N,N',N'-tetraacetic acid (EDTACOOH), which is an EDTA derivative with a functionalisable carboxylic group, were used to coat NaGdF4 . The carboxylic group was used to insert a polyethylene glycol (PEG) functionality (to give EDTAPEG) to favour better suspension and stealth and/or a fluorescent dye to obtain dual optical/MRI probes. The relaxometric behaviour of these NPs was investigated as a function of the magnetic field strength, and a significant contribution from water molecules hydrogen bonded to the organic coating was evidenced. The chemical stability of the NPs was evaluated both in a physiological medium and in the presence of a strong chelating agent. Finally, the dye-functionalised NPs were tested in ovarian carcinoma cells as dual optical and MRI probes.

Experimental Study of Two-Phase Flow in a Horizontal Circular Channel: Influence of Gas Injection on the Bubble Diameters

This study aimed to examine experimentally the effects of the injector on two-phase flow characteristics such as local void fraction and bubble diameter for water-air two- phase flow in a horizontal channel having 40 mm inner diameter. During the experiments, flow rate was kept constant at 3 l/s while that for air is taken as 30 and 60 l/min. Measurements were made locally via dual optical probe and the results were presented.

Time resolved X-ray densitometry for cavitating and ventilated partial cavities

Gas cavities, natural and ventilated, can occur on ship propulsors, control surfaces and hulls. These cavities can be significant sources of small bubbles in the ship wake. This paper presents a two-dimensional time resolved X-ray densitometry system developed for investigation of natural, ventilated and mixed cavities. First the authors consider the limitations and performance of the X-ray system, and compare the measured void fraction to stationary known void fraction, and to data for a ventilated cavity obtained using dual fiber optical probes. Second, the authors present preliminary data from time-resolved X-ray used to observe the overall dynamics and time dependent void fraction distribution of a cavitating backward facing step with and without gas injection.

Experimental study of kerosene–water two‐phase flow in a vertical pipe using hot‐film and dual optical probes

AbstractThe local parameters for kerosene–water upward flow are measured in a vertical pipe of 77.8 mm inner diameter at 4200 mm from the inlet (L/D = 54) using hot‐film and dual optical probes. The effect of superficial water velocity and volumetric quality on radial distribution of two‐phase flow parameters is investigated. The results show the following: (i) the profiles of volume fraction and drop frequency are very similar, and increasing superficial water velocity at low volumetric qualities (<18.6%) change the profile from a convex shape with peak at the pipe centreline to uniform then to concave shape with peak near the wall; (ii) the profiles of drop cut chord change from a parabolic shape with peak at centreline for low superficial water velocities to a flat shape at higher superficial water velocity, and the area‐averaged drop diameter decreases with higher superficial water velocities for all volumetric qualities; (iii) velocity profiles for both phases have shapes similar to single phase flow, flatter at higher values of superficial water velocity and volumetric quality and centreline peaked at low superficial water velocities and volumetric qualities; (iv) the slip velocity decreases with radial distance having a peak at centreline and zero values near the wall; (v) introducing kerosene drops into single phase water flow results in a sharp increase in turbulent intensity, particularly at low water velocity, and the difference between the single phase and two‐phase flow turbulence intensities decreases with higher superficial water velocities and (vi) the results show that interfacial area concentration increased with higher volumetric quality and higher number of bubbles thereby increases the contact area between the two phases. © 2012 Canadian Society for Chemical Engineering

Development of kerosene–water two‐phase up‐flow in a vertical pipe downstream of A 90° bend

AbstractThe development of kerosene–water up‐flow in a vertical pipe of 77.8 mm inner diameter and 4500 mm, length downstream of a 90° bend, has been investigated using a Pitot tube and dual optical probe. The CFD ANSYS Fluent 12.0 is used to model the flow and the results are compared with experimental data. The CFD provides detailed information on flow structure which is difficult to obtain in experiments. The experimental measurements of the local parameters demonstrate that the single phase and two‐phase flows reached the fully developed axisymmetrical conditions at L/D = 54. These results also show the severe asymmetry distributions of the two‐phase flow parameters at the entrance region (L/D = 1). The predictions from Fluent are found to be in close agreement with experimental data for L/D ≥ 16 but there is a significant discrepancy at L/D = 1. © 2011 Canadian Society for Chemical Engineering

Evaluation of hot-film, dual optical and Pitot tube probes for liquid–liquid two-phase flow measurements

An experimental study of kerosene–water upward two-phase flow in a vertical pipe was carried out using hot-film, dual optical and Pitot tube probes to measure the water, kerosene drops and mixture velocities. Experiments were conducted in a vertical pipe of 77.8 mm inner diameter at 4.2 m from the inlet (L/D=54). The tests were carried out for constant superficial water velocities of 0.29, 0.59 and 0.77 m/s (flow rates = 83, 167 and 220 l/min) and volume fractions of 4.2%, 9.2%, 18.6% and 28.2%. The Fluent 6.3.26 was used to model the single and two-phase flow and to reproduce the results for the experimental study. Two methods were used to evaluate the accuracy of the probes for the measurement of the velocities of water, drops and mixture for two-phase flow: (i) comparison of measured local velocities with predictions from the CFD simulation; (ii) comparison between the area-averaged velocities calculated from the integration of the local measurements of water, drops and mixture velocities and velocities calculated from flow meters’ measurements. The results for single phase flow measured using Pitot tube and hot-film probe agree well with CFD predictions. In the case of two-phase flow, the water and drops velocities were measured by hot-film and dual optical probes respectively. The latter was also used to measure the volume fraction. These three measured parameters were used to calculate the mixture velocity. The Pitot tube was also used to measure the mixture velocity by applying the same principle used for single phase flow velocity. Overall the mixture local velocity measured by Pitot tube and that calculated from hot-film and dual optical probe measurements agreed well with Fluent predictions. The discrepancy between the mixture area-averaged velocity and velocity calculated from flow meters was less than 10% except for one test case. It is concluded that the combined hot-film and optical approach can be used for water and drop velocity measurements with good accuracy for the flow conditions considered in this study. The Pitot tube can also be used for the measurement of mixture velocities for conditions of mixture velocities greater than 0.4 m/s. The small discrepancy between the predictions and experimental data from the present study and literature demonstrated that both instrumentation and CFD simulations have the potential for two-phase flow investigation and industrial applications.