scholarly journals Relationship between Photoelasticity of Polyurethane and Dielectric Anisotropy of Diisocyanate, and Application of High-Photoelasticity Polyurethane to Tactile Sensor for Robot Hands

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 143
Author(s):  
Masahiko Mitsuzuka ◽  
Yuho Kinbara ◽  
Mizuki Fukuhara ◽  
Maki Nakahara ◽  
Takashi Nakano ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Optical Constant ◽  
Unit Volume ◽  
Incident Light ◽  
Tactile Sensor ◽  
Dielectric Anisotropy ◽  
Bending Stress ◽  
Robot Hands

Eight types of polyurethane were synthesized using seven types of diisocyanate. It was found that the elasto-optical constant depends on the concentration of diisocyanate groups in a unit volume of a polymer and the magnitude of anisotropy of the dielectric constant of diisocyanate groups. It was also found that incident light scattered when bending stress was generated inside photoelastic polyurethanes. A high sensitive tactile sensor for robot hands was devised using one of the developed polyurethanes with high photoelasticity.

scholarly journals Signal Amplification in an Optical and Dielectric Biosensor Employing Liquid Crystal-Photopolymer Composite as the Sensing Medium

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Hassanein Shaban ◽  
Shih-Chun Yen ◽  
Mon-Juan Lee ◽  
Wei Lee
Keyword(s):  
Dielectric Constant ◽  
Liquid Crystal ◽  
Uv Irradiation ◽  
Signal Amplification ◽  
Limit Of Detection ◽  
Optical Signal ◽  
Uv Exposure ◽  
Dielectric Anisotropy ◽  
Optical Texture ◽  
Potential Development

An optical and dielectric biosensor based on a liquid crystal (LC)–photopolymer composite was established in this study for the detection and quantitation of bovine serum albumin (BSA). When the nematic LC E7 was doped with 4-wt.% NOA65, a photo-curable prepolymer, and photopolymerized by UV irradiation at 20 mW/cm2 for 300 s, the limit of detection determined by image analysis of the LC optical texture and dielectric spectroscopic measurements was 3400 and 88 pg/mL for BSA, respectively, which were lower than those detected with E7 alone (10 μg/mL BSA). The photopolymerized NOA65, but not the prepolymer prior to UV exposure, contributed to the enhanced optical signal, and UV irradiation of pristine E7 in the absence of NOA65 had no effect on the optical texture. The effective tilt angle θ, calculated from the real-part dielectric constant ε’, decreased with increasing BSA concentration, providing strong evidence for the correlation of photopolymerized NOA65 to the intensified disruption in the vertically oriented LC molecules to enhance the optical and dielectric signals of BSA. The optical and dielectric anisotropy of LCs and the photo-curable dopant facilitate novel quantitative and signal amplification approaches to potential development of LC-based biosensors.

scholarly journals The scattering of light by turbid media.–Part II

1931 ◽  
Vol 131 (817) ◽  
pp. 464-475 ◽  
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Spherical Shell ◽  
Direct Observation ◽  
Single Particle ◽  
Unit Volume ◽  
Incident Light ◽  
Parallel Beam ◽  
Photometric Observations ◽  
Transmission And Reflection

In Part I it was shown how the values of the transmission and reflection of a sheet of a medium containing particles in suspension can he calculated. First the amounts of light scattered in the forward and forward directions from a single particle were determined; from these results the transmission 1 and rejection R for diffuse incident light were found for a layer of the disusing medium, when the effects of boundary reflections are negligible. At this stage, the expressions developed apply to a mist or fog consisting of particles suspended in air. Finally it was shown how, if the particles are suspended in some other medium, having a different refractive index from that of air, the transmission and reflection ז and p can be expressed in terms of T and R and the surface rejection coefficients. The more general expressions, for the case when the incident light is a parallel beam, were also developed. We shall now show how the absorption coefficient μ can be determined from photometric observations. As a check on the theory, we shall deduce the diameter D of the particles and the number N present per unit volume and compare these calculated values with those found by direct observation, Finally, the necessary modifications of the theory will be made to cover the case when the diffusing medium is in the form of a spherical shell.

scholarly journals Dielectric properties of the system: 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4᾽-methylaniline

2021 ◽  
Vol 16 (2) ◽  
pp. 138-147
Author(s):  
S. A. Syrbu ◽  
M. S. Fedorov ◽  
E. A. Lapykina ◽  
V. V. Novikov
Keyword(s):  
Crystal Structure ◽  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Anisotropy ◽  
Specific Electrical Conductivity ◽  
Conductivity Anisotropy ◽  
Independent Molecules ◽  
System Properties ◽  
The Individual

Objectives. Our aim was to study the dielectric properties of the 4-n-pentyloxybenzoic acid– N-(4-n-butyloxybenzylidene)-4’-methylaniline system and reveal how different concentrations of N-(4-n-butyloxybenzylidene)-4’-methylaniline additives affect the dielectric properties of 4-n-pentyloxybenzoic acid.Methods. System properties were investigated using polarization thermomicroscopy and dielcometry.Results. We found that dielectric anisotropy changes its sign from positive to negative at the transition temperature of the high-temperature nematic subphase to the low-temperature one. The anisotropy of the dielectric constant of N-4-n-butoxybenzylidene-4’-methylaniline has a positive value and increases as to the system approaches the crystalline phase. The crystal structure of the 4-n-pentyloxybenzoic acid contains dimers formed by two independent molecules due to a pair of hydrogen bonds. The crystal structure of N-(4-n-butoxybenzylidene)-4’-methylaniline contains associates formed by orientational interactions of two independent molecules. 4-n-Pentyloxybenzoic acid dimers (270 nm) and associates of N-4-n-butoxybenzylidene-4’- methylaniline (250 nm) proved to have approximately the identical length. Considering the close length values of the structural units of both compounds and the dielectric anisotropy sign, we assume that the N-4-n-butoxybenzylidene-4’-methylaniline associates are incorporated into the supramolecular structure of the 4-n-pentyloxybenzoic acid. The specific electrical conductivity of the compounds under study lies between 10−7 and 10−12 S∙cm−1. The relationship between the specific electrical conductivity anisotropy and the system composition in the nematic phase at the identical reduced temperature, obtained between 100 and 1000 Hz is symbatic. However, the electrical conductivity anisotropy values of the system obtained at 1000 Hz are lower compared to those obtained at 100 Hz. At N-(4-n-butoxybenzylidene)-4’-methylaniline concentrations between 30 and 60 mol %, the electrical conductivity anisotropy values are higher than those of the individual component.Conclusions. A change in the sign of the dielectric constant anisotropy of the 4-n-pentyloxybenzoic acid during nematic subphase transitions was established. We showed that the system has the highest dielectric constant anisotropy value when components have an equal number of moles. Highest electrical conductivity anisotropy values are observed when the concentration of the N-4-n-butoxybenzylidene-4᾽-methylaniline system lies between 30 and 60 mol %. 

scholarly journals Characterization of Volume Gratings Based on Distributed Dielectric Constant Model Using Mueller Matrix Ellipsometry

2019 ◽  
Vol 9 (4) ◽  
pp. 698 ◽  
Author(s):  
Hao Jiang ◽  
Zhao Ma ◽  
Honggang Gu ◽  
Xiuguo Chen ◽  
Shiyuan Liu
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Minimum Mean Square Error ◽  
Incident Light ◽  
Mueller Matrix ◽  
Distribution Functions ◽  
Refractive Index Distribution ◽  
Index Distribution ◽  
Constant Distribution ◽  
Volume Gratings

Volume grating is a key optical component due to its comprehensive applications. Other than the common grating structures, volume grating is essentially a predesigned refractive index distribution recorded in materials, which raises the challenges of metrology. Although we have demonstrated the potential application of ellipsometry for volume grating characterization, it has been limited due to the absence of general forward model reflecting the refractive index distribution. Herein, we introduced a distributed dielectric constant based rigorous coupled-wave analysis (RCWA) model to interpret the interaction between the incident light and volume grating, with which the Mueller matrix can be calculated. Combining with a regression analysis with the objective to match the measured Mueller matrices with minimum mean square error (MSE), the parameters of the dielectric constant distribution function can be determined. The proposed method has been demonstrated using a series of simulations of measuring the volume gratings with different dielectric constant distribution functions. Further demonstration has been carried out by experimental measurements on volume holographic gratings recorded in the composite of polymer and zinc sulfide (ZnS) nanoparticles. By directly fitting the spatiotemporal concentration of the nanoparticles, the diffusion coefficient has been further evaluated, which is consistent to the result reported in our previous investigations.

scholarly journals Surface Plasmons for Probing Optical Data of Multi- Layered Thin Films

2000 ◽  
Vol 5 ◽  
pp. 105
Author(s):  
A. Rais ◽  
A. Sellai
Keyword(s):  
Surface Plasmons ◽  
Optical Constant ◽  
Incident Light ◽  
Air Gap ◽  
Optical Data ◽  
Layered System ◽  
Geometrical Parameters ◽  
Matrix Formalism ◽  
Minimization Method ◽  
Al Oxide

In this paper, we show how optical excitation of surface plasmons (SPs) can be used to obtain optical and geometrical parameters of specific layers in multi-layered thin film systems. The optimum coupling phenomenon between incoming p-polarized light and SPs appears as a minimum in the reflectance that is calculated using a standard matrix formalism. The sensitive dependence of the reflectance minimum on optical and geometrical parameters suggests that they can be determined accurately by fitting the measured attenuated total reflectance (ATR) to the matrix-calculated reflectance using the Simplex minimization method. The procedure is applied to the multi-layered system: Prism / Air gap / Al-oxide / Al / GaAs. At fixed incident light wavelength, the fitting parameters are the Al-oxide optical constant and the thickness of the air gap, Al-oxide and Al layers. Fortran codes are implemented for the reflectance calculations and the fitting procedures. The results show that the theoretical reflectance fits well the measured ATR at 633 nm wavelength. Moreover, the modeled Al-oxide optical constant at this wavelength agrees well with the literature. However, the reflectance fits are less good at 590 nm and 458 nm wavelengths and their modeled Al-oxide optical constants show a dispersion effect in disagreement with the literature. The modeled geometrical parameters are consistent with the nominal values.

scholarly journals Soft Biomimetic Optical Tactile Sensing with the TacTip: A Review

2021 ◽  
Author(s):  
Nathan Lepora
Keyword(s):  
Tactile Sensor ◽  
Step Change ◽  
Tactile Sensors ◽  
The Past ◽  
Robot Hands ◽  
Human Touch ◽  
Skin Morphology ◽  
Sense Of Touch ◽  
And Control ◽  
Human Sense

<div>Reproducing the capabilities of the human sense of touch in machines is an important step in enabling robot manipulation to have the ease of human dexterity. A combination of robotic technologies will be needed, including soft robotics, biomimetics and the high-resolution sensing offered by optical tactile sensors. This combination is considered here as a SoftBOT (Soft Biomimetic Optical Tactile) sensor. This article reviews the BRL TacTip as a prototypical example of such a sensor. Topics include the relation between artificial skin morphology and the transduction principles of human touch, the nature and benefits of tactile shear sensing, 3D printing for fabrication and integration into robot hands, the application of AI to tactile perception and control, and the recent step-change in capabilities due to deep learning. This review consolidates those advances from the past decade to indicate a path for robots to reach human-like dexterity.</div><div><br></div>

scholarly journals A Comparative Study of Conductance of Sodium Dodecyle Sulphate (SDS) in Different Percentage of Ethanol Water Mixed Solvent Media at 298.15 K Temperature

NUTA Journal ◽  
2018 ◽  
Vol 5 (1-2) ◽  
pp. 67-71
Author(s):  
Chandradip Kuma Yadav
Keyword(s):  
Dielectric Constant ◽  
Comparative Study ◽  
Sodium Dodecyl Sulphate ◽  
Sharp Increase ◽  
Unit Volume ◽  
Precise Measurement ◽  
Mixed Solvent ◽  
Sodium Dodecyl ◽  
Increase With Increase

Precise measurement of the conductivity of sodium dodecyl sulphate in different percentage of (0%, 10%, 20%) ethanol-water mixed solvent media containing at 298.15 K temperature were measured. The specific conductivities exhibit a sharp increase with increase in concentration with in the concentration range investigated (0.001 to 0.020) mol per liter. The increase in the conductance with concentration is due to an increase in the number of ion per unit volume of the solution. But decrease in conductance with increase in percentage of ethanol - water mixed solvent media at particular temperature 298.15 K. Ionizing effect is decrease with increase in percentage of ethanol - water mixed solvent media at 298.15K. Due to decrease in dielectric constant with increase in percentage of ethanol - water mixed solvent media at particular temperature 298.15 K. conductivity order is 0% > 10% > 20% at particular temperature 298.15 K.

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