Transparent Liquid Research Articles

Synthesis and characterization of solvent-free ionic molybdenum disulphide (MoS2) nanofluids

A development of the novel and stable solvent-free ionic MoS2 nanofluids by a facile and scalable hydrothermal method is presented. The nanofluids were synthesized by surface functionalizing nanoscale MoS2 from hydrothermal synthesis with a charged corona, and ionically tethering with oligomeric chains as a canopy. The structures and properties of the nanofluids were characterized by Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR, 1H), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and ARES rheometer. The obtained solvent-free nanofluids are homogeneous, stable amber-like fluids with no evidence of phase separation. The nanofluids could be easily dispersed in both aqueous and organic solvents to form transparent and stable liquids due to the ionic nature and the presence of oligomeric polymer chains. It was found that the solvent-free nanofluids with up to 32 wt% inorganic content show Newtonian rheological behaviors due to the high graft density and uniform dispersion of inorganic cores, indicating that the nanofluids would have a stable lubricating performance. As reported in our previous communication, the nanofluids showing lower, more stable friction coefficients of less than 0.1 with self-healing lubricating behaviors. For deeper understanding of the nanofluids, the details of synthesis, chemical structures, rheological behaviors and molecular dynamics of the nanofluids were investigated in details. The rheological behaviors can be tailored by varying the grafting density of the canopy. Dynamic results of the canopy of the MoS2 nanofluids show that inorganic MoS2 cores have hindrance effect on the canopy segmental motions above 253 K due to their effect to the mobility of anions and the departing-recombining motions between the paired cations and anions.

Adsorption of Xylene From Air by Natural Iranian Zeolite

Background: Aromatic organic solvents are extensively used in various industries. Xylene is a colorless, transparent liquid, with the characteristic odor of the aromatic hydrocarbons family, which is widely used in industries. Adsorption is a conventional method of purifying polluted air containing volatile organic compounds (VOCs). Zeolite has many unique properties such as high capacity, molecular sieve characteristics, nonflammability, thermal stability, and strong acid sites. Moreover, it is reconstructed at low temperatures. Objectives: In this study, we investigated the effect of various parameters on the adsorption capacity of natural zeolite (clinoptilolite) for xylene adsorption. Materials and Methods: Physical and chemical properties of natural zeolites were tested by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) and elemental analyses of natural zeolites were characterized by X-ray diffraction. Xylene concentration was measured at various times through concentrations-measured valve before and after the adsorbent bed reactor by the direct reading of Phocheck (Ion Science Ltd, UK). Results: Experimental results showed that clinoptilolite is a potential sorbent for xylene in the range of ppm, and the breakthrough time would be reduced by increasing the concentration. The optimal temperature of xylene adsorption on natural zeolite was 35℃ and by increasing the temperature, the absorption efficiency of clinoptilolite was declined. The results showed that the breakthrough time and the exhaustion point time at the optimal conditions are 65 and 95 minutes, respectively. Adsorption capacity of clinoptilolite was obtained as 1.69 mg xylene/g zeolite. Conclusions: Experimental results showed that clinoptilolite is a potential sorbent for xylene in the range of ppm and the breakthrough time was reduced by increasing the concentration. Adsorption rate were increased by increasing concentration of xylene. Presence of xylene molecules in high concentration enhances their transfer and contact with adsorbent; as a result, by increasing gas concentration, breakthrough time in zeolite will be shorter.

Polymer-Dispersed Liquid Crystal Applied in Active-Matrix Transparent Display

In this paper, we have developed an active-matrix thin-film transistor (TFT) transparent liquid crystal display (LCD) by using polymer dispersed liquid crystal (PDLC) technology. Also, there are some advantages, such as being polyimide-less, polarizer-free, environmental-light only, and so on. In addition, their transmittance of the transparent state is upward 40%, the transmittance of the scattering state is under 3%, and the driving voltage is under 6 V. The transparent display has high transparency, good visibility, and low electric consumption.

A Detection System of Impurity in Transparent Liquid

In the fields of transparent liquid impurity detection based on machine vision technology, how to effectively detect impurities in the liquid is a difficult problem which has not yet been solved, mainly in the low recognition rate, the slow recognition speed, and the phenomenon of error detection and undetected. Therefore, this paper presents a new impurity detection method. Firstly, the hardware structure of the system is introduced in this paper. Then the flow diagram of impurity detection is presented. Finally, the algorithm of impurity detection is studied. Experiments show that the system introduced in this paper can identify impurities in liquid well on condition of ensuring the detection speed and detection accuracy.

Imaging of mass transfer process using artificial fringe deflection

A noninterferometric technique used to measure the diffusion coefficients of transparent liquid solutions is reported. This technique uses a white light source and a diffusion cell, with an artificially developed fringe pattern of dark and white stripes at its entrance. As the diffusion process takes place in the cell, the light passing through this nonuniform refractive index medium will bend toward the higher refractive index region, which results in a fringe shift. This shift in the fringe pattern at different times is recorded in a personal computer (PC) using a CCD camera for the calculation of diffusion coefficients. The fringe shift is calculated after skeletonization and linear fit of the captured fringe system. The diffusion coefficient of different concentrations of ammonium dihydrogen phosphate was determined using the proposed technique and the measured values lay within 1% of the reported values. Detailed theoretical and experimental analyses with a comparison of other existing results are discussed.

Unentangled star-shape poly(ε-caprolactone)s as phthalate-free PVC plasticizers designed for non-toxicity and improved migration resistance.

We develop a nontoxic unentangled star-shape poly(ε-caprolactone) (UESPCL) plasticizer with excellent migration resistance for the production of phthalate-free flexible poly(vinyl chloride) (PVC) by means of the ring-opening polymerization of ε-caprolactone, initiated from the multifunctional core, combined with end-capping, and vacuum purification processes. UESPCL is a transparent liquid at room temperature and exhibits unentangled Newtonian behavior because of its extremely short branched segments. UESPCL is biologically safe without producing an acute toxicity response. Torque analysis measurements reveals that UESPCL offers a faster fusion rate and a higher miscibility with PVC compared to a typical plasticizer, di(2-ethylhexyl) phthalate (DEHP). The solid-state (1)H nuclear magnetic resonance (NMR) spectrum reveals that PVC and UESPCL are miscible with an average domain size of less than 8 nm. The flexibility and transparency of the PVC/UESPCL mixture, that is, phthalate-free flexible PVC, are comparable to the corresponding properties of the PVC/DEHP mixture, and the stretchability and fracture toughness of PVC/UESPCL are superior to the corresponding properties of the PVC/DEHP system. Most of all, PVC/UESPCL shows excellent migration resistance with a weight loss of less than 0.6% in a liquid phase, whereas DEHP migrated out of PVC/DEHP into a liquid phase with a weight loss of about 10%.

A single-element interferometer for measuring refractive index of transparent liquids

A simple and stable method based on a single-element interferometer for accurately measuring refractive index of transparent liquids was demonstrated. The refractive index is measured by rotating a rectangular optical glass cell which contains sample liquid and air simultaneously, and by calculating interference fringe shift number which is detected from an interferogram. This method was successfully used to measure the refractive indices of various transparent liquids including distilled water, ethanol and NaCl–water and ethanol–water solutions at various concentrations. The temperature- dependent refractive index of distilled water was also measured. Furthermore, our method is simple to implement, vibration insensitive, and of high accuracy up to 10−4.

A high transmittance color liquid crystal display mode with controllable color gamut and transparency.

In this paper, we propose a color transparent liquid crystal (LC) mode that can control the properties of the color gamut and transparency in a single panel. To achieve high transmittance in the transparent LC mode, a reactive mesogen (RM) with embedded color dichroic dyes was applied instead of a color filter. Basically, the LC mode applied a 3-terminal electrode structure to switch between the transparent LC mode and the conventional color LC mode. Depending on the direction of the applied voltage, we can operate both the color mode and the transparent mode in a single panel, and modulate the transparency and color purity of the cell through appropriate voltage control. In the experiments, we confirmed that the transmittance and the color gamut of the cell were 39.4% and 2% in the transparent LC mode and 14.9% and 34% in the color LC mode, respectively. Modulation of the color gamut and transparency between each LC mode are also demonstrated in the paper.

Clear Microfluidics Imaging Through Flowing Blood by Digital Holography

Achieving a clear vision through turbid fluids is a highly desirable goal in microfluidics. In particular, observing particles dipped inside blood shows fascinating perspectives in all fields of bio-medical research. White-light microscopy cannot provide clear imaging due to the strong scattering of light by red blood cells. Here we solve the problem by Digital Holography microscopy. We show that, in cases where the blood flows along a microfluidic channel at sufficient speed, the hologram acts as a selective filter. This occurs due to the Doppler frequency shift experienced by the photons hitting the red blood cells, discarding the unwanted scattering. In cases where the blood flow is not quick enough to take advantage of the Doppler shift, multiple holograms can be processed to produce a clear image of the object. We show that the correlation coefficients between multiple acquisitions at different fluid speeds can be adopted to study the visibility of the fringes due to the moving colloidal particles in the medium. Hence, we estimate the threshold velocity required to completely discard all the scattered photons. In this way the object is seen as dipped in a transparent liquid thus completely eliminating the negative effect of turbidity on the imaging.

On the influence of the magnetic field upon hydrogasdynamic processes in a boiling magnetic fluid

The processes of the growth and separation of the vapor bubbles in a boiling magnetic liquid were experimentally and theoretically modeled. Experimental results of the influence of a homogeneous constant magnetic field upon the volume and departure frequency of magnetic fluid drops from a horizontal surface in a transparent nonmagnetic liquid are presented. The mechanism of the influence of the magnetic field upon the volume and departure frequency of the magnetic fluid drops is explained. The shape and volume of a magnetic liquid drop placed in a nonmagnetic environment are theoretically calculated for various values of the magnetic field intensity the drop is exposed to.

Best fit refractive index of matching liquid for 3D NIPAM gel dosimeters using optical CT

Abstract The accuracy of an optical computed tomography (CT)-based dosimeter is significantly affected by the refractive index (RI) of the matching liquid. Mismatched RI induces reflection and refraction as the laser beam passes through the gel phantom. Moreover, the unwanted light rays collected by the photodetector produce image artifacts after image reconstruction from the collected data. To obtain the best image quality, this study investigates the best-fit RI of the matching liquid for a 3D NIPAM gel dosimeter. The three recipes of NIPAM polymer gel used in this study consisted of 5% gelatin, 5% NIPAM and 3% N,N'-methylene bisacrylamide, which were combined with three compositions (5, 10, and 20 mM) of Tetrakis (hydroxymethyl) phosphonium chloride. Results were evaluated using a quantitative evaluation method of the gamma evaluation technique. Results showed that the best-fit RI for the non-irradiated NIPAM gel ranges from 1.340 to 1.346 for various NIPAM recipes with sensitivities ranging from 0.0113 to 0.0227. The greatest pass rate of 88.00% is achieved using best-fit RI=1.346 of the matching liquid. The adoption of mismatching RI decreases the gamma pass rate by 2.63% to 16.75% for all three recipes of NIPAM gel dosimeters. In addition, the maximum average deviation is less than 0.1% for the red and transparent matching liquids. Thus, the color of the matching liquid does not affect the measurement accuracy of the NIPAM gel dosimeter, as measured by optical CT.

Non-Intrusive Technique for Measuring Refractive Index of Clear and Transparent Liquids

We propose an optical technique for measuring refractive index of clear and transparent liquids. This technique senses change in refractive index of liquid by virtue of lateral displacement of a light beam that occurs due to refraction of the light beam after passing through the liquid medium. The transmitted light beam gradually looses its alignment with a photodetector as refractive index of the liquid changes. Experimental results have indicated that the proposed technique has the potential to measure refractive indexes with an accuracy of 10-4, and it has novelty of being a simple and non-intrusive one.

A low voltage submillisecond-response polymer network liquid crystal spatial light modulator

We report a low voltage and highly transparent polymer network liquid crystal (PNLC) with submillisecond response time. By employing a large dielectric anisotropy LC host JC-BP07N, we have lowered the V2π voltage to 23 V at λ = 514 nm. This will enable PNLC to be integrated with a high resolution liquid-crystal-on-silicon spatial light modulator, in which the maximum voltage is 24 V. A simple model correlating PNLC performance with its host LC is proposed and validated experimentally. By optimizing the domain size, we can achieve V2π < 15 V with some compromises in scattering and response time.

Transparent and colourless room temperature ionic liquids having high refractive index over 1.60.

Transparent and colourless ionic liquids with refractive index over 1.60 were synthesised by combining 1-benzyl-3-methylimidazolium or hexyltriphenylphosphonium cations with suitable anions. There is a positive relation between their refractive index and Kamlet-Taft parameters, especially dipolarity/polarisability, suggested as a potential parameter to design ionic liquids with high refractive index.

Structural transformation of liquid water under shock compression condition

Using shock wave loading and real time optical transmission measurements, the transmission spectra of liquid water compressed between the quartz windows under pressures in a range of 1-1.6 GPa are obtained. A discontinuity of liquid water at nearly 0.9 GPa during the shock is observed. Combining the phase diagram of water with calculation results, it is suggested that the discontinuity of liquid water is due to a possible phase transition from low density water to high density water under the experimental conditions. The method can also be used to study other transparent molecular liquids in shock compression experiments.

Validation of Plate-type Cell for Micro-Raman Analysis of Liquid Sample

Recently, the use of the Micro-Raman spectrometer for the analysis of chemical materials is attracting attention in applied chemistry and advanced technologies due to the easiness of measurement. However, in the case of a liquid sample, there is some difficulty to analyze it, especially in focusing the laser beam on a transparent liquid sample accurately by using conventional vessels, such as the NMR tube and capillaries. We report here on the validation of a newly-designed cell for Micro-Raman spectroscopy that could more easily analyze a liquid sample than using conventional vessels. This cell is a small rectangular block (30×30×15 mm) made of aluminum alloy having a cylindrical hole (Φ10×5 mm) at center of the surface. First, the hole is filled with an aqueous solution or organic solvent, and then covered with a thin glass plate. By focusing the laser beam anywhere on the bottom surface of the hole, a high signal with sufficient intensity is easily detected. Similarly, a measurement using a cell made of another material, such as stainless steel, glass or polypropylene (PP) is tested. Finally, we conclude that aluminum alloy is the most suitable to be used for the cell material, due to its overall signal intensity, workability of material, low cost, resistance to chemicals and no interference to the Raman signal.

Real-Time Liquid Evaporation Rate Measurement Based on a Microchip Laser Feedback Interferometer

We present a novel scheme to realize the direct real-time measurement of liquid evaporation rate and nanometer order liquid level monitoring. It is based on the phase measurement technology of Nd:YAG microchip laser frequency-shifted feedback, which not only has a high resolution and precision but also ultrahigh sensitivity. The evaporation rates of four different transparent liquids and hot water are measured. Experimental results indicate the ease and convenience of measuring and present promising application prospects in non-cooperative target measurement.

Ultrafast single-shot imaging of femtosecond pulse propagation in transparent liquids using a supercontinuum and optical polarigraphy

We investigated the ultrafast time-resolved single-shot imaging of femtosecond pulse propagation using a supercontinuum and optical polarigraphy in transparent liquids. The probe supercontinuum senses the instantaneous birefringence induced by the laser pulse, and a polarigraphy image with different color distributions could be obtained. By comparing the wavelength distributions and the saturation variation of the images, the recorded polarigraphy images in two samples with different response time were analyzed. In the fast response sample, N-methyl-2-pyrrolidone (NMP), the spectral widths and the saturation values of the polarigraphy image at fixed positions were narrower and higher than those in CS2. Due to the slow response of CS2, the probe light sensed a long-lived birefringence and the polarigraphy image contained more wavelength components at every position along the pump pulse propagation direction.

A method for spatial recording of waves on the surface of a transparent liquid

A method for recording standing waves on the surfaces of transparent liquids is proposed. A contrast pattern (grid) is placed on the bottom of a liquid-filled transparent cell and is photographed through a liquid layer in transmitted light. The shape of the vibrating liquid surface can be reconstructed from the distortions in the pattern image.

The study of detecting method for impurity in transparent liquid

How to detect and identify various kinds of impurities in transparent liquid effectively using machine vision is still a difficult task which has not been solved. The existing significant problems include the slow recognition speed, the lower recognition accuracy and the false and missing detection. Therefore, this paper presents a new impurity detection method. First, cluster the images captured using fuzzy c-means clustering algorithm and combine the clustering results with the improved least squares filtering to achieve impurity image background suppression. Then the method based on target counter area and prior knowledge is used to achieve target detection and tracking between frames. Finally, grading recognition strategy is used to improve the identification effect. In the pre-identifying stage, targets gray, size and position are used to achieve detection too-large impurities and normal small particles quickly. In the second stage, fuzzy least squares support vector machine is adopted to recognize the impurities which are similar with bubbles. The experimental results show the method proposed in this paper can achieve a 98.6% recognition rate while the false detecting rate is only 0.53% and the recognition time can be decreased to 100ms.