Light Transmission Measurements Research Articles

Understanding Flexdispersion: Structure-Function Relationship Studies of Organic Amphiphilic Ligands.

Since inorganic nanoparticles have unique properties that differ from bulk materials, their material applications have attracted attention in various fields. In order to utilize inorganic nanoparticles for functional materials, they must be dispersed without agglomeration. Therefore, the surfaces of inorganic nanoparticles are typically modified with organic ligands to improve their dispersibility. Nevertheless, the relationship between the tail group structure in organic ligands and the dispersibility of inorganic nanoparticles in organic solvents remains poorly understood. We previously developed amphiphilic ligands that consist of ethylene glycol chains and alkyl chains to disperse inorganic nanoparticles in a variety of organic solvents. However, the structural requirements for amphiphilic ligands to "flexibly" disperse nanoparticles in less polar to polar solvents are still unclear. Here, we designed and synthesized several phosphonic acid ligands for structure‒function relationship studies of flexdispersion. Dynamic light scattering analysis and visible light transmittance measurements revealed that the ratio of alkyl/ethylene glycol chains in organic ligands alone does not determine the dispersibility of the nanoparticles in organic solvents, but the arrangement of the individual chains also has an effect. From a practical application standpoint, it is preferable to design ligands with ethylene glycol chains on the outside relative to the particle surface.

Low-temperature preparation of nanostructured porous sol-gel anti-reflective coating for near-infrared wavelengths

Anti-reflective coatings are crucial in minimizing reflection between different optical media at the interfaces. This study aims to develop an anti-reflective layer for the near-infrared region using a sol-gel coating method combined with a low-temperature plasma-jet-assisted surfactant extraction. For the deposition of the sol-gel layer on glass and polycarbonate substrates, dip-coating and spray-coating techniques were used. Surfactant removal was carried out using a plasma-jet and solvent exchange. Some of the samples were also annealed at 450 °C. The samples were characterized through light transmission measurements, haze percentage determination, 3D laser scanning microscopy, scanning electron microscopy, profilometry, Fourier transform Infrared spectroscopy, ellipsometry and atomic force microscopy. The results showed that the anti-reflective coating layer treated with a plasma-jet and solvent exchange at room temperature demonstrated broadband anti-reflective properties with high transmission in near-infrared regions (up to 7.6% relative improvements in transmission for two sides). Annealing, performed only on the glass substrate, also showed the maximum relative improvement in transmission up to 8% for two sides. Moreover, in the case of polymer-based substrates, a low-temperature process is essential, which is implemented successfully by a plasma-jet method. These findings highlight the effectiveness of the proposed method for fabricating anti-reflective layers on both glass and polycarbonate substrates, offering potential applications in various industries, e.g. where either low-temperature fabrication or cost-cutting, quick and “simple” production methods play a major role for the feasibility of products as in mass markets.

Light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis

AbstractThe light transmittance measurement method, which is used to characterize smoke characteristic signal of solid rocket motor plume, can provide important reference for development and design of low smoke characteristic signal solid propellants and motors. The light transmittance measurement method of solid rocket motor plume based on laser modulation spectrum analysis is proposed in this paper. By using a 405 nm laser as the light source and a narrow‐band filter detection method, the influence of plume radiation on the measurement of light transmittance of solid rocket motor plume smoke can be minimized. Additionally, combined with the laser modulation spectrum analysis technology, the signal amplitude is selected by the laser modulation frequency to improve the signal‐to‐noise ratio of the signal. Compared with the laser constant current measuring mode, laser high‐frequency modulation measuring mode with spectrum analysis effectively improves the optical transmittance measurement accuracy. Based on this, a solid rocket motor plume smoke transmittance test system is developed to measure the plume smoke of standard test motors with different propellants and combustion chamber pressures. The results demonstrate that the system can effectively measure the light transmittance of the plume smoke. The light transmittance of solid rocket motor plume can be increased by reducing the aluminum content of solid propellant or increasing the pressure of the combustion chamber. Thus, this research provides an effective measuring tool for evaluating smoke concentration of solid rocket motor plume, which is beneficial to develop low smoke characteristic signal solid propellants and motors.

Plastic Fiber Low Light Measurement Method

Paper describe researches performed to develop a method for checking the light transmission through plastic scintillating fiber. Such fibers are used in different industrial or research application but for our purpose are main components of a flexible detector. Such detector use photon scintillating signals read by higly sensitive detectors and special measures taken to get such sensitivity. We present in paper a method and algorithm developed for measurement of light transmission through plastic fiber when signals are at level of nW. We develop a stand to implement and verify this method. We use fibers with connectors at each fiber end. Fibers are previously polished at each end in order to allows to pass the signal through surface with low losses. Using the stand we perform measurements to analyse the feasibility of method. We present the results that demonstrate the feasibility of method. We succeed to measure signals at level of nW using special measures. Our results shows that method and stand can be used to measure low level signals through fibers. Using this method, it is possible to check the quality of plastic fiber polishing. A fiber with end surface well-polished allows to pass the signal at such low level (nW).

Study on the Memory Effect in Aerosil-Filled Nematic Liquid Crystal Doped with Magnetic Nanoparticles

A study on 5CB liquid crystal composites with SiO2 nanoparticles and an additional commixture with Fe3O4 nanoparticles using light transmission and SAW measurements is presented. The prepared liquid crystal composites exhibited an interesting memory effect characterized by the hysteresis of both light transmission and SAW attenuation responses investigated in the nematic phase. While in the case of SiO2 nanoparticles as dopants, the liquid crystal composite showed an improvement in the memory effect, the addition of Fe3O4 magnetic nanoparticles resulted in the memory effect decreasing. Additional studies showed a significant shift in both the threshold voltage and nematic–isotropic transition temperature. Measurements in the magnetic field confirmed the increasing memory effect according to that of pure 5CB. The properties of these composites could lead to a potential application for the fabrication of memory devices suitable for information storage.

Assessing soil aggregate stability by measuring light transmission decrease during aggregate disintegration

Assessing soil aggregate stability by measuring light transmission decrease during aggregate disintegration

Light transmittance in human atrial tissue and transthoracic illumination in rats support translatability of optogenetic cardioversion of AF

Abstract Background Optogenetics could offer a solution to the current lack of an ambulatory method for rapid automated cardioversion of AF, but key translational aspects remain to be studied. Objective To investigate whether optogenetic cardioversion of AF is effective in the aged heart and whether sufficient light penetrates the human atrial wall. Methods Atria of adult (7 weeks old) and aged (2 years old) rats were optogenetically modified to express light-gated ion channels (i.e. ReaChR), followed by AF induction and atrial illumination to determine effectivity of optogenetic cardioversion. The irradiance level was determined by light transmittance measurements on human atrial tissue. Results AF could be effectively terminated in remodelled atria of aged rats (97%, n=6). Next, in terms of ReaChR activation, it was shown that light pulses of 25mW/mm2 are expected to fully penetrate the human atrial wall (∼2 mm). Applying such irradiation onto the chest of adult rats resulted in full transthoracic illumination (also ∼2 mm) as evidenced by optogenetic cardioversion of AF (90%, n=4). Conclusion Optogenetic cardioversion of AF is effective in the aged rat heart and can also be realized with irradiation levels compatible with human atrial transmural light penetration.

Investigation of IR Reflective Coating for Plexiglas Canopy

Purpose: Solar energy is necessary for our global ecosystem. In certain times and parts of the world, the heat generated from the energy of the Sun becomes uncomfortable for us and we need to use additional energy to cool down the generated heat from the Sun. This additional energy usage is detrimental to our environment due to generation of air pollution and use of our natural energy resources. The purpose of this paper is to investigate prevention of undesired generation of heat by the Sun using reflective coating materials.
 Methodology: In this study, using literature review, Ga doped Zinc Oxide (GZO) is theoretically investigated as a visible light transparent and infrared reflective coating material for the Plexiglas canopy of a solar car. The effect of doping concentration and film thickness is reviewed and discussed. Indium Tin Oxide (ITO) is also studied, using various literature reviews, as an infrared reflective coating material that is transparent in the visible light region. Finally, a spectrophotometer was used to examine the optical properties of a Plexiglas, slide glass, and ITO coated glass, and the results of UV and visible light transmittance measurement of the three materials is presented and discussed.
 Findings: GZO and ITO films both have high transparency in the visible region of the solar spectrum and high reflectivity to IR radiation starting from 1500 nm to higher wavelengths. None of these films completely reflect the IR radiation with wavelengths in the range of 700 nm to 1500 nm which contribute to generation of heat most. Many factors such as doping concentration and thickness of the films affect reflectivity of the films due to their effect on shifting the plasma frequency. Increasing doping concentration and thickness of the GZO films until a certain threshold improves IR reflectivity of GZO films, but it was not possible to precisely formulate these factors within this study. Reducing the particle size in nanoparticle ITO film improves transmittance of the film in the visible light region and its reflectance in the IR region. The measurement results showed that Plexiglas and glass have a high transparency to visible and near IR radiation.
 Recommendations: Further investigation and experimentation is recommended to fully understand and formulate doping concentration and film thickness of GZO and ITO to achieve optimal IR reflectivity within the 700 to 1500 nm wavelength region while maintaining visible light transparency. In regards to ITO coating, reduced nanoparticle size is recommended to improve the desired visible and IR transparency and reflectivity of the film. Although GZO and ITO coatings’ doping concentration and thickness to achieve IR reflectivity within the 700 to 1500 nm wavelengths is not well understood in this study, to reduce heat generation they are still recommended as a coating material due to their reflectivity to IR with wavelengths of above 1500 nm which also play a role in generation of heat.

Light transmittance in human atrial tissue and transthoracic illumination in rats support translatability of optogenetic cardioversion of atrial fibrillation.

Optogenetics could offer a solution to the current lack of an ambulatory method for the rapid automated cardioversion of atrial fibrillation (AF), but key translational aspects remain to be studied. To investigate whether optogenetic cardioversion of AF is effective in the aged heart and whether sufficient light penetrates the human atrial wall. Atria of adult and aged rats were optogenetically modified to express light-gated ion channels (i.e., red-activatable channelrhodopsin), followed by AF induction and atrial illumination to determine the effectivity of optogenetic cardioversion. The irradiance level was determined by light transmittance measurements on human atrial tissue. AF could be effectively terminated in the remodeled atria of aged rats (97%, n=6). Subsequently, ex vivo experiments using human atrial auricles demonstrated that 565-nm light pulses at an intensity of 25mW/mm2 achieved the complete penetration of the atrial wall. Applying such irradiation onto the chest of adult rats resulted in transthoracic atrial illumination as evidenced by the optogenetic cardioversion of AF (90%, n=4). Transthoracic optogenetic cardioversion of AF is effective in the aged rat heart using irradiation levels compatible with human atrial transmural light penetration.

The Effects of Citric Acid as Crosslinking Agent on Selected Properties of Cassava Starch Films

Materials made from renewable resources offer a promising strategy for reducing environmental problems. Starch is a well-known alternative among several biodegradable materials due to its availability, cheap cost, and degradability. This research aims to develop a degradable film from cassava starch and use citric acid as the crosslinker. Light transmittance measurement reveals that the films produced have high UV barrier capacity in the UV region and above 80% transmittance values in the visible region. Additionally, it was found that the film with 10% citric acid had a favorable balance of tensile strength, elongation, and fracture stress.

Wafer-scale hysteresis-free plasmonic hydrogen sensors based on Pd–Au alloy nanoarrays

The prospective market of hydrogen energy has dramatically boosted the demand for accurate and stable detection of ambient hydrogen. In this work, we fabricated wafer-scale plasmonic hydrogen sensors consisting of periodically distributed Pd–Au alloy nanodiscs by holographic lithography and other semiconductor-compatible techniques, thus obtaining reliable and low-cost sensing devices. Light transmittance measurements at specific light wavelength close to the plasmonic absorption peak position are conducted to investigate the hydrogen sensing performance on account that optical signals afford spark-free operation and high tolerance. Upon alloying Pd with appropriate content of Au, the hysteresis between hydrogen absorption and desorption curves is completely suppressed which greatly improves the sensing accuracy throughout the hydrogen pressure range of 102–105 Pa. Moreover, the precisely defined Pd–Au alloy nanodiscs provide satisfactory stability and device-to-device reproducibility. This work demonstrates an attractive route into practical applications of hydrogen detection for the facile fabrication method and satisfactory performance.

Study of the V[formula omitted] state in neutron-irradiated silicon using photon-absorption measurements

Pieces of n-type silicon with 3.5kΩ cm resistivity have been irradiated by reactor neutrons to 1MeV neutron equivalent fluences of (1, 5 and 10)×1016cm−2. Using light-transmission measurements, the absorption coefficients have been determined for photon energies, Eγ, between 0.62 and 1.30eV for the samples as irradiated and after 15min isochronal annealing with temperatures between 80°C and 330°C. The radiation-induced absorption coefficient, αirr, has been obtained by subtracting the absorption coefficient for non-irradiated silicon. The Eγ-dependence of αirr shows a resonance peak, which is ascribed to the neutral divacancy, V20, sitting on a background, and αirr(Eγ) is fitted by a Breit–Wigner line shape on a parameterized background. It is found that at an annealing temperature of 210∘C the V20 intensity is reduced by a factor 2, and that at the meV level, the position and the width of the fitted Breit–Wigner do not change with irradiation dose and annealing.

Optical and flexoelectric biosensing based on a hybrid-aligned liquid crystal of anomalously small bend elastic constant

Liquid crystal (LC)-based biosensors rely on the response of the LC molecules to perturbation generated by analytes at the interface, leading to the susceptible change in molecular alignment or orientation. The sensitivity of these biosensors is primarily dependent on the LC's material properties and surface anchoring strength. By incorporation of an unconventional mesogenic compound (CB7CB) coupled with the hybrid-alignment cell configuration, this work presents a binary nematic LC for label-free biosensing, manifesting a novel sensing technology that takes advantage of CB7CB-induced flexoelectricity in the transducer. Herein, we prepared LC mixtures by blending a typical rod-like nematic LC (E7) with the bent-core mesogen CB7CB in various weight ratios and studied the effect of the CB7CB content on E7/CB7CB-based biosensing performance in vertically aligned and hybrid-aligned nematic (HAN) cells. Owing to the anomalously small bend elastic constant K33 in CB7CB, the mixture designated CB45 with the highest CB7CB weight percentage (45 wt% in this study) was best applicable to biosensing in HAN cells. When observed under a polarizing optical microscope, CB45 in the HAN geometry showed the capability of detection of as low as 10−10 g/mL for the protein standard bovine serum albumin (BSA). Moreover, the quantitation of the assay was fulfilled by both dielectric and light transmission measurements of the hybrid-aligned cholesteric CB45/R5011. The limit of detection of 7 × 10−10 g/mL was achieved by spectrometric analysis. To the best of our knowledge, this work is the first to demonstrate flexoelectric biosensing on the basis of flexoelectric polarization associated with giant flexoelectricity in CB7CB partially constituting the LC transducer.

PbWO4 Acoustic Properties Measurement by Laser Ultrasonics with the Aim of Optical Damage Recovery

The paper, at first, discusses theoretical aspects of acoustic wave propagation in lead tungstate (PWO). After that, it introduces the application of laser ultrasonics to PWO crystals with the aim of measuring the acoustic properties and the absorbed energy. A specific set-up has been developed to deposit energy in the crystals by means of shock waves generated by a pulsed Nd-YAG laser. We measured the acoustic properties of the PWO crystals along the crystallographic c^ axis and measured the acoustic energy absorption. Calculations confirmed that the majority of the energy has been absorbed in the samples. Since in scintillating crystals the radiation damage leads to a decrease in the optical transmission, the paper formulates the hypothesis that the laser energy absorbed can sustain recovery of the optical transmittance properties. Preliminary tests of light transmittance measurements showed a systematic improvement of optical transmittance after laser treatment in a series of PWO samples. These results are consistent and in agreement with the hypothesis, and they support the feasibility of a laser-based method to recover radiation-damaged crystals.

In situ measurement of light transmission into wine bottles and calculation of shelf life

Wine exposed to UV-A and violet light (320–440 nm) can develop a light-struck flavour which deteriorates its quality. In a short introduction, we briefly describe the two most important photochemical pathways of this process and discuss conditions that facilitate the formation of undesired compounds. The main thrust of the study is to use a novel method to determine light transmission into real wine bottles, along with optical and photochemical modelling of wine damage. Calculation of light transmission into bottles and resulting photochemical damage is described in detail and compared to in situ measurements of transmitted light inside bottles. The effect of different light sources (sunlight, fluorescent bulbs and LED bulbs) is also discussed. It is found in in situ measurements that clear (flint) bottles transmit up to 35 % and bluish-green bottles up to 8 % of the harmful UV–violet light, while light amber bottles only up to 1.2 % and dark amber ones up to 0.2 %. Results of simple tasting experiments support the validity of shelf life calculations described here. According to these findings, white wine in flint (clear) and bluish-green bottles can survive only for a few days while displayed on shelves; light amber bottles conserve the quality for about a month and dark amber bottles for more than a year.  Recommendations concerning the protection of shelf-displayed bottled wine from light exposure are also given.

Correlation between transcutaneous bilirubin levels and total serum bilirubin levels in postnatal period in a tertiary care center

Background: Neonatal jaundice is generally a benign condition seen during the postnatal period. The non-invasive methods including transcutaneous bilirubinometry have been developed for assessment of neonatal jaundice, transcutaneous bilirubin TcB) meters noninvasively estimate the bilirubin levels by measuring light transmission through the skin of neonates this value is then to be plotted against a chart in order to look for hyperbilirubinemia. Aim was to determine the efficacy of measuring the transcutaneous bilirubin as a screening tool for clinically significant hyperbilirubinemia. Methods: Study was a cross sectional study conducted under pediatric department of SMBT IMS and RC at tertiary care center after taking the approval from the ethical committee. Total of 110 neonates that appear to be clinically suffering from neonatal jaundice were considered for study after consent from respective parent/ guardian. Neonatal TCB levels and serum bilirubin levels were done. If bilirubin levels lie in phototherapy range, then baby was shifted to NICU and phototherapy treatment was given, and once levels came within normal range after the phototherapy treatment, again serum bilirubin levels were measured in order to compare pre-and post-treatment levels. Results: Present study showed male preponderance. 64 were male and 46 were female. Majority 61% were full term normal delivery and 39% were LSCS. Mean TCB level was 8.5±2.8. Statistical significance was seen for TCB and sever hyperbilirubinemia. Conclusions: Present study concluded that hyperbilirubinemia is commonly seen among males. Newborn delivered had hyperbilirubinemia. Statistical significance was seen between TCB level and severity of the disease.  Thus, neonatal TCB levels can be used as a screening test for detecting hyperbilirubinemia in neonates. As TCB is a noninvasive and cost effective it can be used widely as predictor of the disease.

Platelet Functional Testing Via High-Throughput Microtiter Plate-Based Assays.

Platelets play a critical role in hemostasis and thrombosis; therefore, in vitro assays that measure platelet reactivity are fundamental tools to gain insight into these physiologic processes, to diagnose platelet disorders, and to develop antithrombotic therapies. However, conventional platelet assays such as aggregometry, the clinical gold standard for assessing platelet function, are low throughput and require specialized equipment. Since platelets have a finite life span ex vivo, processes to miniaturize and multiplex assays allow a much broader overview of platelet function in significantly less time than conventional assays. Several groups have developed simplified, high-throughput approaches to quantify platelet activation with standard laboratory equipment to lower the barrier of entry to study platelet biology. This article describes a panel of optimized and validated high-throughput microplate assays to comprehensively assess platelet functionality, independently or in combination, to increase throughput and reduce costs. Specifically, following stimulation of platelets, a plate reader can be used to measure light transmission aggregation via absorbance; dense-granule secretion based on ATP-dependent luminescence generation; and cytosolic calcium levels with a cell-permeant, fluorescent Ca2+ -sensitive dye. Additionally, platelets are an easily accessible component of the blood that share signaling pathways with other cells, making them ideal for high-throughput drug screens. The highly adaptable and complementary assays presented in this article can be used to decipher the molecular mechanism underlying platelet activation or to identify novel inhibitors. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Microtiter plate-based light transmission aggregometry Basic Protocol 2: Measuring dense-granule secretion in high-throughput microplate assays Basic Protocol 3: Microtiter plate-based calcium mobilization Support Protocol: Platelet isolation and enumeration.

Influence of Goethite Nanorods on Structural Changes and Transitions in Nematic Liquid Crystal E7

A composite ferronematic system based on the nematic liquid crystal E7, doped with lath-like goethite magnetic nanoparticles of volume concentrations 10−3, 5 × 10−4, and 10−5, was investigated. Both surface acoustic waves (SAWs) and the magneto-optical effect were used to study the influence of magnetic nanoparticles on ferronematic liquid crystals’ structural changes, focused above all on structural transitions. The responses of SAW attenuation and light transmission to external magnetic fields were investigated experimentally under linearly increasing/decreasing or jumped (time influence) magnetic fields, respectively. An investigation of temperature on structural changes was performed, as well. The experimental results validated the decrease in the threshold field of the ferronematic composites in comparison with the pure E7, as well as an increase in the transition temperature with the increasing volume fraction of nanoparticles. The effect of the nanoparticles’ concentration on both total structural changes and residual attenuations at the vanishing magnetic field was also registered. The light transmission measurements confirmed the effect of the concentration of goethite nanoparticles on the resultant magneto-optical behavior, concerning both its stability and switching time.

DEVELOPMENT OF RADIATION RESISTANT SCINTILLATORS BASED ON RARE-EARTH ALUMINATES

LuYAG:Ce and YAG:Ce,Ca crystals were obtained by the Czochralski method using tungsten crucibles in reducing surroundings. Crystals (LuxY1-x)3Al5O12:1%Ce and crystals of YAG:Ce,Ca with different concentrations of Ce and Ca were grown. Studies and analyses of their characteristics were carried out. The analysis of their characteristics is based on experimental data that we obtained by measurements of light output, decay time, spectra of luminescence, excitation, and light transmittance.

The Effect of Surface Characteristics of Clays on the Properties of Starch Nanocomposites.

In this research, different clays such as laponite and montmorillonite (NaMMT) are used as fillers in the preparation of thermoplastic starch/clay nanocomposites. Thin films are produced by casting and evaporation in a wide composition range, using glycerol as the plasticizer at two different concentrations. The surface energy of clay fillers is measured by inverse gas chromatography (IGC); X-ray diffraction (XRD) and light transmission measurements (UV-VIS) are carried out to characterize the structure of nanocomposites; and mechanical properties and water vapor permeability are also studied. While all the starch/montmorillonite nanocomposites possess intercalated structures, significant exfoliation can be noted in the starch/laponite nanocomposites, mainly at low clay contents. Due to the larger surface energy of montmorillonite, stronger polymer/clay interactions and better mechanical properties can be assumed in starch/NaMMT composites. The smaller surface energy of laponite, however, can facilitate the delamination of laponite layers. Thus, the specific surface area of laponite can be further increased by exfoliation. Based on the results, the better exfoliation and the much larger specific surface area of laponite lead to higher reinforcement in starch/laponite nanocomposites.