Real-time Holographic Interferometry Research Articles

Exploring isotropic tendency for the blue membrane containing wild-type bacteriorhodopsin

Bacteriorhodopsin of purple membrane has wide potential applications in bioelectronics and biophotonic nanodevices. Upon acidification, it turns blue and upon further acidification by HCl, it retains its purple color. The acid-induced structural changes might be correlated to its crystalline structure, which might be mediated by lipids of purple membrane. Therefore, the present study aims at revealing the acidic pH dependence of anisotropic properties of bacteriorhodopsin. The electric impedance has been measured for parallel- and perpendicular-oriented purple membrane, in addition to the randomly-oriented one in the acidic pH range. The results have showed that the electric anisotropy is proportional to the color transitions occurred at low pH with consistent pKa values. It has found that the bacteriorhodopsin, upon turning into blue form, tends to be isotropic within narrow pH region around 2.55, whereas it preserves its anisotropy in its purple form. It is noteworthy that several mutants of bacteriorhodopsin that resemble its blue form became attractive in technical applications such as real-time holographic interferometry and optical data storage. Accordingly, such isotropic tendency might implicate bacteriorhodopsin for further potential technical applications.

Holographic Interferometry for Measuring the Effect of Thermal Modification on Wood Thermal Properties

The paper focuses on the use of holographic interferometry in the research of thermal modification and its effect on the heat transfer from the wood surface to the surrounding air. In the experiment, spruce wood samples modified at 160 °C, 180 °C, 200 °C, 220 °C and an unmodified control sample were used. A radiant heat source was placed under the sample. The top of the sample represented the boundary where the observed heat transfer occurred. The temperature fields above the sample were visualized by real-time holographic interferometry and the heat transfer coefficient α was calculated from the obtained interferograms. During the heating of the samples, a decrease of the heat transfer coefficient was observed. The heat transfer coefficient of the control unmodified sample decreased from a maximum of α = 22.66 Wm–2K–1 to a minimum of α = 8.6 Wm–2K–1. In comparison with these values, the heat transfer coefficients of the modified samples treated at 160, 180, 200 and 220 °C, respectively, decreased to 99%, 93%, 68% and 51% of the maximal control value at the beginning of experiment and to 95%, 86%, 80% and 64% of the minimal control value by the end of the experiment. Moreover, an analysis of variance was used to determine the significance of the heat treatment effect on the heat transfer coefficient. A high significance (p < 5%) was observed between the control sample and the modified samples treated at 200 °C and 220 °C. Experiments with the use of holographic interferometry produced results consistent with previous studies conducted by different methods.

The history of holographic vibration analysis

This paper describes the evolution of holographic vibration analysis from its discovery in 1964 to its present form as a technique of digital holography. The speckle interferometer is discussed as a replacement for real-time holographic interferograms and electronic speckle pattern interferometry (ESPI) as the precursor to digital holography. The development of methods for converting vibratory (Jo) fringe patterns into numerical data is discussed along with applications to Modal Assurance Criteria (MAC) calculations. Finally, an application is presented for vibratory strain measurement in one dimension.

Regulation of the sensitivity of measurements in holographic interferometry of dynamic periodic structures

This paper discusses the features of the recording of a hologram of a periodic structure that make it possible when implementing a method of either real-time or double-exposure holographic interferometry to adjust the measurement sensitivity when investigating the temporal behavior of the periodic structure of an object. Experimental test results of the real-time holographic interferometry method, devised while studying the dynamics of two-dimensional periodic structures in time, are presented.

Opto-Electrochemical Spectroscopy

Opto-electrochemistry is the state of the art and technology of not only imaging surfaces of a condensed matter, i.e., solid metal, submerged in aqueous solutions, but also, the science of measuring electrochemical properties of the condensed matter by solely light. In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminium samples during the initial stage of anodisation processes in aqueous solution. In fact, because the resistance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the resistance was called electrical resistance–emission spectroscopy. The anodisation process of the aluminium samples was carried out by electrochemical impedance spectroscopy (EIS) in different sulphuric acid concentrations (1.0–2.5% H2SO4) at room temperature. In the meantime, the real time holographic interferometry was used to determine the difference between the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the EIS experiment for the aluminium samples in 1.0, 1.5, 2.0 and 2.5% H2SO4 solutions. The electrical resistance–emission spectra of the present investigation represent a detailed picture of not only the rate change of the electrical resistance throughout the anodisation processes but also the spectra represent the rate change of the growth of the oxide films on the aluminium samples in different solutions. As a result, a new spectrometer was developed based on the combination of the holographic interferometry and electrochemical impedance spectroscopy for studying in situ the electrochemical behavior of metals in aqueous solutions. Keywords: Holographic interferometry; Electrical resistance; Anodisation process; Electrochemical impedance spectroscopy (EIS); Sulphuric acid; Aluminium.

Opto-electrochemical spectroscopy of metals in aqueous solutions.

In the present investigation, holographic interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminium samples during the initial stage of anodisation processes in aqueous solution. In fact, because the resistance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the resistance was called electrical resistance-emission spectroscopy. The anodisation process of the aluminium samples was carried out by electrochemical impedance spectroscopy (EIS) in different sulphuric acid concentrations (1.0%-2.5% H2SO4) at room temperature. In the meantime, the real time holographic interferometry was used to determine the difference between the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the EIS experiment for the aluminium samples in 1.0%, 1.5%, 2.0%, and 2.5% H2SO4 solutions. The electrical resistance-emission spectra of the present investigation represent a detailed picture of not only the rate change of the electrical resistance throughout the anodisation processes but also the spectra represent the rate change of the growth of the oxide films on the aluminium samples in different solutions. As a result, a new spectrometer was developed based on the combination of the holographic interferometry and electrochemical impedance spectroscopy for studying in situ the electrochemical behavior of metals in aqueous solutions.

Electrical Resistance-Emission Spectroscopy for Determining the Electrochemical Behavior of Anodized Aluminum in Aqueous Solutions

Holographic interferometry was utilized for the first time to determine the rate change of the electrical resistance of aluminum samples during the initial processes of anodization of the samples in aqueous solution without any physical contact. In fact, because the electrical resistance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the electrical resistance was called the electrical resistance –emission spectroscopy. The anodization process of the aluminum samples was carried out by the electrochemical impedance spectroscopy (EIS) test in different sulfuric acid concentrations (1.0–2.5% H2SO4) at room temperature. In the meantime, the real time holographic interferometry was used to determine the difference in the electrical resistance of two subsequent values, dR, as a function of the elapsed time of the EIS test for the aluminum samples in 1. 0, 1.5, 2.0 and 2.5% H2SO4 solutions. The electrical resistance–emission spectra of the present investigation represent a detailed picture of not only the rate change of the electrical resistance throughout the anodization processes but also the spectra represent the rate change of the growth of the oxide films on the aluminum samples in different solutions. Consequently, holographic interferometry is found to be very useful for surface finish industries, especially for monitoring the early stage of anodization processes of metals, in which the rate change of electrical resistance of the aluminum samples can be determined in situ. Keywords: holographic interferometry; electrochemical impedance spectroscopy (EIS); anodization process; oxide film thickness; sulfuric acid; aluminum.

G0600105 仕切りによる垂直平板上端部に平板を設置した場合の角部の熱伝達特性への影響

This research investigated the influence of partition on the heat transfer characteristics in the corners of the vertical heated plate and the inclined heated flat plate attached to its top end in open space using real-time holographic interferometry and laser sheet method. The partition was set parallel to the vertical plate. The interval between the vertical plate and partition was varied from 5mm to 70mm. Then, the gap between the top of partition and the inclined plate was varied from 20mm to 40mm. The experiment was made at the angle of the corner 60° and the surface temperature of two plates 70℃. As a result, it was found that heat transfer at the corner may be increased under certain specific conditions between partition and the circulating flow produced by interference of upward flow along each plate

Capture and display mismatch compensation for real-time digital holographic interferometry.

Optical holographic interferometry (HI) is realized by two well-known techniques: double exposure holographic interferometry (DEHI) and real-time holographic interferometry (RTHI). However, the digital version of HI is typically realized numerically by DEHI. The main problem in digital implementation of RTHI is the lack of commercially available cameras and spatial light modulators with the same pixel size. This mismatch results in lateral and transversal magnifications of an object wavefront reconstruction. In real-time digital HI the reconstruction of an object in an initial state has to be superimposed on top of the loaded object. In this work, we present and analyze five approaches to overcome the mismatch problem, and the performance of these procedures is numerically quantified and compared. The experimental suitability of these approaches is investigated.

Effect of Heat Transfer on Natural Convection in a Square Cavity With Two Source Pairs

In this paper, the influence of a small heating source, positioned in the lateral walls of a square cavity, is investigated. Numerical and experimental analyses are performed to investigate natural convection heat transfer in a square cavity heated by hot strips in the side walls. The H side square cavity is filled with air and heated by two hot strips with heights of H/4. The effect of placing the hot strips at two different positions is evaluated. The temperature distribution and the Nusselt numbers at different Rayleigh numbers are experimentally measured using both real-time and double-exposure holographic interferometry. The isothermal patterns obtained through the holographic interferometry are compared with the temperature and velocity fields from a numerical study performed using the finite-volume code Fluent.

Biomechanical model produced from light-activated dental composite resins: a holographic analysis

Light-activated dental composites, commonly applied in dentistry, can be used as excellent material for producing biomechanical models. They can be cast in almost any shape in an appropriate silicone mold and quickly solidified by irradiation with light in the blue part of the spectrum. In that way, it is possible to obtain any number of nearly identical casts. The models can be used to study the behavior of arbitrary structure under mechanical loads. To test the technique, a simple mechanical model of the tooth with a mesio–occluso–distal cavity was manufactured. Composite resin restoration was placed inside the cavity and light cured. Real-time holographic interferometry was used to analyze the contraction of the composite resin and its effect on the surrounding material. The results obtained in the holographic experiment were in good agreement with those obtained using the finite element method.

Surface resistivity/conductivity of oxide–hydroxide compounds in inhibited seawater by optical interferometry

Optical interferometry techniques were used to measure the surface resistivity/conductivity of carbon steel samples in blank seawater and in seawater with different concentrations of a corrosion inhibitor, without any physical contact. The measurement of the surface resistivity/conductivity of carbon steel samples was carried out in blank seawater and in seawater with a concentration range of 5–20ppm of RA-41 corrosion inhibitor, at room temperature. In this investigation, the real-time holographic interferometry was carried out to measure the thickness of anodic dissolved layer or the total thickness, Utotal, of the formed oxide layer of carbon steel samples during the alternating current (AC) impedance of the samples in blank seawater and in 5–20ppm RA-41 inhibited seawater, respectively. In other words, the surface resistivity/conductivity of carbon steel samples was determined simultaneously by holographic interferometry, an electromagnetic method, and by the Electrochemical Impedance (E.I) spectroscopy, an electronic method. In addition, a mathematical model was derived in order to correlate between the AC impedance (resistance) and to the surface (orthogonal) displacement of the surface of the samples in solutions.

Thermal Stress Monitoring on Piston Rings by Real Time Holographic Interferometry

In this paper, real time holographic Interferometry (RTHI) technique was used to monitor the thermal stress on the piston rings. The piston rings holograms were recorded and the holographic plate replaced on the holder after development. The piston ring was subjected to thermal stress as it was illuminated by Laser beam acting as the object beam. This process led to generation of interferograms which were captured by a CCD camera at different temperatures. The captured interferograms were analyzed using atmosfringe version 3.3 software. From the analysis, the peak to valley (P-V) aberrations measured for each of the piston ring varied for the same temperature value. The P-V aberrations ranging from 0.0128λ to 1.2989λ were obtained. From this result, it was evident that the three rings on the piston had different unique structural characteristics due to their function.

Measurement of volume resistivity/conductivity of metallic alloy in inhibited seawater by optical interferometry techniques

Optical interferometry techniques were used for the first time to measure the volume resistivity∕conductivity of carbon steel samples in seawater with different concentrations of a corrosion inhibitor. In this investigation, the real-time holographic interferometry was carried out to measure the thickness of anodic dissolved layer or the total thickness, U(total), of formed oxide layer of carbon steel samples during the alternating current (ac) impedance of the samples in blank seawater and in 5-20 ppm TROS C-70 inhibited seawater, respectively. In addition, a mathematical model was derived in order to correlate between the ac impedance (resistance) and the surface (orthogonal) displacement of the surface of the samples in solutions. In other words, a proportionality constant [resistivity (ρ) or conductivity (σ) = 1∕ρ] between the determined ac impedance [by electrochemical impedance spectroscopy (EIS) technique] and the orthogonal displacement (by the optical interferometry techniques) was obtained. The value of the resistivity of the carbon steel sample in the blank seawater was found similar to the value of the resistivity of the carbon steel sample air, around 1 × 10(-5) Ω cm. On the contrary, the measured values of the resistivity of the carbon steel samples were 1.85 × 10(7), 3.35 × 10(7), and 1.7 × 10(7) Ω cm in 5, 10, and 20 ppm TROS C-70 inhibited seawater solutions, respectively. Furthermore, the determined value range of ρ of the formed oxide layers, from 1.7 × 10(7) to 3.35 × 10(7) Ω cm, is found in a reasonable agreement with the one found in literature for the Fe oxide-hydroxides, i.e., goethite (α-FeOOH) and for the lepidocrocite (γ-FeOOH), 1 × 10(9) Ω cm. The ρ value of the Fe oxide-hydroxides, 1 × 10(9) Ω cm, was found slightly higher than the ρ value range of the formed oxide layer of the present study. This is because the former value was determined by a dc method rather than by an electromagnetic method, i.e., holographic interferometry with applications of EIS, i.e., ac method. As a result, erroneous measurements were recorded due to the introduction of heat to Fe oxide-hydroxides.

Measurement of Bulk Resistivity/Conductivity of Carbon Steel in Inhibited Seawater by Holographic Interferometry Techniques

Optical interferometry techniques were used to measure the surface resistivity/conductivity of carbon steel samples in blank seawater and in seawater with different concentrations of a corrosion inhibitor, without any physical contact. The measurement of the surface resistivity/conductivity of carbon steel samples was carried out in blank seawater and in seawater with a concentration range of 5–20 ppm of KGR-134 corrosion inhibitor, at room temperature. In this investigation, the real-time holographic interferometry was carried out to measure the thickness of anodic dissolved layer or the total thickness, Utotal, of formed oxide layer of carbon steel samples during the alternating current (AC) impedance of the samples in blank seawater and in 5–20 ppm KGR-134 inhibited seawater, respectively. In other words, the surface resistivity/conductivity of carbon steel samples was determined simultaneously by holographic interferometry, an electromagnetic method, and by the Electrochemical Impedance (E.I) spectroscopy, an electronic method. In addition, a mathematical model was derived in order to correlate between the AC impedance (resistance) and to the surface (orthogonal) displacement of the surface of the samples in solutions.

Phase-shifting Real-time Holographic Microscopy applied in micro-structures surface analysis

The microscopic real-time analysis of micro structured materials is of great importance in various domains of science and technology. For other hand, the holographic interferometry comprises a group of powerful optical methods for non-destructive testing in surface analysis. The holographic microscopy uses the holographic interferometric techniques to obtain quantitative intensity and phase information of the optical waves by microscopic systems. With the development of CCD cameras, computers (hardware and software), and new materials for holographic recording, these techniques can be used to replace the classical form of registration and became promising tools in surface analysis. In this work, we developed a prototype of Photorefractive and Digital Holographic Microscope for real-time analysis of micro-structured systems based on the phase-shifting real-time holographic interferometry techniques. Using this apparatus, we are made analysis of shapes and surfaces to obtain the phase maps and the 3D profiles of some samples.

AC impedance–emission spectroscopy for determining the electrochemical behaviour of anodised aluminium in aqueous solutions

In the present investigation, holographic interferometry was utilised for the first time to determine the rate change of the alternating current (AC) impedance of aluminium samples during the initial stage of anodisation processes in aqueous solution without any physical contact. In fact, because the AC impedance values in this investigation were obtained by holographic interferometry, electromagnetic method rather than electronic method, the abrupt rate change of the AC impedance was called AC impedance–emission spectroscopy. The anodisation process (oxidation) of the aluminium samples was carried out chemically in different sulphuric acid concentrations (0.5–3.125% H2SO4) at room temperature. In the mean time, the real time holographic interferometry was used to determine the difference in the AC impedance of two subsequent values, dZ, as a function of the elapsed time of the experiment for the aluminium samples in 0. 5, 1.0, 1.5 and 3.125% H2SO4 solutions. The AC impedance–emission spectra of the present investigation represent a detailed picture of not only the rate change of the AC impedance throughout the anodisation processes but also the spectra represent the rate change of the growth of the oxide films on the aluminium samples in different solutions. Consequently, holographic interferometry is found to be very useful for surface finish industries, especially for monitoring the early stage of anodisation processes of metals, in which the rate change of AC impedance of the aluminium samples can be determined in situ.

Highly sensitive and spatially resolved polyvinyl alcohol/acrylamide photopolymer for real-time holographic applications

By employing low molecular-weight polyvinyl alcohol (PVA) as binder, the spatial resolution of a red-sensitive PVA/acrylamide based photopolymer are improved from 1000 lines/mm to 3000 lines/mm. By increasing the ambient temperature during the holographic recording, the photosensitivity of photopolymer is also increased about 5 times. The optimized photopolymer system has high capacity such as high photosensitivity (8 mJ/cm(2)), high spatial resolution (over 3000 lines/mm) and high diffraction efficiency (over 94%). To our knowledge, its holographic recording performance is the best of ever reported PVA/acrylamide based photopolymer systems. It has good application prospects in real-time holographic interferometry, holographic storage and holographic display.

HOLOGRAPHIC INTERFEROMETRY AS A METHOD FOR MEASURING STRAIN CAUSED BY POLYMERIZATION SHRINKAGE OF DENTAL COMPOSITE

Савремени материјали, међународна научна конференција - Contemporary materials, International scientific conference,Савремени материјали 2010 - научна конференција у Бањој Луци

Mass diffusion coefficients of oxygenated fuel additives in air

Abstract In this work, an experimental system based on digital real-time holographic interferometry for measuring the mass diffusion coefficients of fluid is introduced. The method of processing interference fringe hologram is also introduced thoroughly. By uncertainties analysis and experimental verification, the accuracy of this system is validated. The experimental uncertainties in temperature and mass diffusion coefficient are estimated to be no greater than ± 0.16 K and ± 0.2%, respectively. On this basis, mass diffusion coefficients of two fuel additives: 1,2-dimethoxyethane (ethyleneglycol dimethyl ether, GDME) and 2-methoxyethyl ether (diethylene glycol dimethyl ether, DGM) in air were measured at T = (278.15–338.15) K under atmospheric pressure, and polynomial was fitted by the experimental data.