scholarly journals Research on Optical Properties of Tapered Optical Fibers with Liquid Crystal Cladding Doped with Gold Nanoparticles

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 306 ◽  
Author(s):  
Joanna E. Moś ◽  
Joanna Korec ◽  
Karol A. Stasiewicz ◽  
Bartłomiej Jankiewicz ◽  
Bartosz Bartosewicz ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Liquid Crystal ◽  
Optical Fibers ◽  
Surrounding Medium ◽  
Environmental Parameters ◽  
Different Temperatures ◽  
Properties Of Materials ◽  
Time Courses ◽  
Materials Used ◽  
Index Value

This paper presents results obtained for biconical tapered fibers surrounded/immersed in liquid crystal mixtures. The phenomenon of light propagating in the whole structure of a tapered fiber allows the creation of a sensor where the tapered region represents a core whereas the surrounding medium becomes a cladding. Created devices are very sensitive to changing refractive index value in a surrounding medium caused by modifying external environmental parameters like temperature, electric or magnetic field. For this reason, the properties of materials used as cladding should be easily modified. In this investigation, cells have been filled with two different nematic liquid crystals given as 1550* and 6CHBT (4-(trans-4-n-hexylcyclohexyl) isothiocyanatobenzoate), as well as with the same mixtures doped with 0.1 wt% gold nanoparticles (AuNPs). Optical spectrum analysis for the wavelength range of 550–1150 nm and time-courses performed for a wavelength of 846 nm at the temperature range of T = 25–40 °C were provided. For all investigations, a steering voltage in the range of 0–200 V which allows establishing the dopes’ influence on transmitted power and time response at different temperatures was applied.

scholarly journals Photo-Aligned Nematic Liquid Crystals Enable the Modulation of Thermoplasmonic Heating

2021 ◽  
Vol 11 (14) ◽  
pp. 6272
Author(s):  
Giovanna Palermo ◽  
Rossella Grillo ◽  
Luigia Pezzi ◽  
Thomas Bürgi ◽  
Nelson Tabiryan ◽  
...  
Keyword(s):  
Thin Film ◽  
Gold Nanoparticles ◽  
Refractive Index ◽  
Liquid Crystal ◽  
Single Layer ◽  
Organic Layer ◽  
Molecular Reorientation ◽  
Index Value ◽  
Director Reorientation ◽  
Director Orientation

We experimentally demonstrate that the plasmonic heat delivered by a single layer of homogeneously distributed gold nanoparticles (AuNPs), immobilized on a glass substrate, can be optically tuned by taking advantage of the properties of an organic layer based on azobenzene and nematic liquid crystal (NLC) molecules. The effect, which exploits the dependence of the NLC refractive index value on the molecular director orientation, is realized using the polarization-dependent, light-induced molecular reorientation of a thin film of photo-aligning material that the NLC is in contact with. The reversibility of the optically induced molecular director reorientation of the NLC enables an active modulation of the plasmonic photo-induced heat.

Rolling Resistance Calculation Procedure Using the Finite Element Method

2019 ◽  
Vol 48 (3) ◽  
pp. 224-248
Author(s):  
Pablo N. Zitelli ◽  
Gabriel N. Curtosi ◽  
Jorge Kuster
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Rolling Resistance ◽  
Element Model ◽  
The Finite Element Method ◽  
Temperature Changes ◽  
Rubber Compounds ◽  
Different Temperatures ◽  
Materials Used ◽  
Account Temperature

ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.

scholarly journals Two helices from one chiral centre – self organization of disc shaped chiral nanoparticles

2021 ◽  
Author(s):  
Huanan Yu ◽  
Wentao Qu ◽  
Feng Liu ◽  
Georg H. Mehl
Keyword(s):  
Gold Nanoparticles ◽  
Liquid Crystal ◽  
Self Organization ◽  
Helix Formation ◽  
Chiral Nematic

Gold nanoparticles (NPs) were surface functionalized with hexanethiol groups and chiral nematic discogen ligands. A superlattice, liquid crystal behaviour and helix formation of the discs and a second helical organisation of the NPs were detected.

scholarly journals Holographic Polymer-Dispersed Liquid Crystals: Materials, Formation, and Applications

2008 ◽  
Vol 2008 ◽  
pp. 1-52 ◽  
Author(s):  
Y. J. Liu ◽  
X. W. Sun
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Refractive Index Profile ◽  
Single Step ◽  
Fast Switching ◽  
Polymer Dispersed Liquid Crystal ◽  
Current State ◽  
Index Matching ◽  
Polymer Dispersed ◽  
Materials Used

By combining polymer-dispersed liquid crystal (PDLC) and holography, holographic PDLC (H-PDLC) has emerged as a new composite material for switchable or tunable optical devices. Generally, H-PDLC structures are created in a liquid crystal cell filled with polymer-dispersed liquid crystal materials by recording the interference pattern generated by two or more coherent laser beams which is a fast and single-step fabrication. With a relatively ideal phase separation between liquid crystals and polymers, periodic refractive index profile is formed in the cell and thus light can be diffracted. Under a suitable electric field, the light diffraction behavior disappears due to the index matching between liquid crystals and polymers. H-PDLCs show a fast switching time due to the small size of the liquid crystal droplets. So far, H-PDLCs have been applied in many promising applications in photonics, such as flat panel displays, switchable gratings, switchable lasers, switchable microlenses, and switchable photonic crystals. In this paper, we review the current state-of-the-art of H-PDLCs including the materials used to date, the grating formation dynamics and simulations, the optimization of electro-optical properties, the photonic applications, and the issues existed in H-PDLCs.

Smart Textiles with Biosensing Capabilities

2012 ◽  
Vol 80 ◽  
pp. 129-135 ◽  
Author(s):  
Stéphanie Pasche ◽  
Bastien Schyrr ◽  
Bernard Wenger ◽  
Emmanuel Scolan ◽  
Réal Ischer ◽  
...  
Keyword(s):  
Real Time ◽  
Optical Fibers ◽  
Close Contact ◽  
Biological Fluids ◽  
Wearable Sensors ◽  
Surrounding Medium ◽  
Sol Gel ◽  
The Body ◽  
In Situ Monitoring ◽  
Easy Integration

Real-time, on-body measurement using minimally invasive biosensors opens up new perspectives for diagnosis and disease monitoring. Wearable sensors are placed in close contact with the body, performing analyses in accessible biological fluids (wound exudates, sweat). In this context, a network of biosensing optical fibers woven in textile enables the fabric to measure biological parameters in the surrounding medium. Optical fibers are attractive in view of their flexibility and easy integration for on-body monitoring. Biosensing fibers are obtained by modifying standard optical fibers with a sensitive layer specific to biomarkers. Detection is based on light absorption of the sensing fiber, placing a light source and a detector at both extremities of the fiber. Biosensing optical fibers have been developed for the in situ monitoring of wound healing, measuring pH and the activity of proteases in exudates. Other developments aim at the design of sensing patches based on functionalized, porous sol-gel layers, which can be deposited onto textiles and show optical changes in response to biomarkers. Biosensing textiles present interesting perspectives for innovative healthcare monitoring. Wearable sensors will provide access to new information from the body in real time, to support diagnosis and therapy.

scholarly journals Effect of Solvent Refractive Index on the Surface Plasmon Resonance Nanoparticle Optical Absorption

2007 ◽  
Vol 7 (12) ◽  
pp. 4333-4338
Author(s):  
Gulay Ertas ◽  
Sefik Suzer
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Surface Plasmon ◽  
Surrounding Medium ◽  
Point Of View ◽  
Experimental Point ◽  
Absorption Bands ◽  
Plasmon Band ◽  
Silver And Gold Nanoparticles ◽  
Band Position

Optical properties of plasmon coupled silver and gold nanoparticles were studied as a function of the refractive index of the surrounding medium. Our studies confirmed that the effect of changes in the refractive index of the surrounding medium was more difficult to demonstrate from an experimental point of view, because of the very high susceptibility of nanoparticles to aggregate in aqueous and organic solvents. Whereas the position of the absorption bands of triiodide in these solvents shows a clear dependence on medium's refractive index, the surface plasmon band position of silver and gold nanoparticles do not exhibit the same dependence. This is attributed to a non-negligible interaction of these solvents with nanoparticle surfaces.

scholarly journals Properties of Materials Used in Roller Compacted Concrete Mixtures

2020 ◽  
pp. 61-72
Author(s):  
Ali Mardani ◽  
Sultan Husein Bayqra ◽  
Süleyman Özen ◽  
Zia Ahmad Faqiri ◽  
Kambiz Ramyar
Keyword(s):  
Roller Compacted Concrete ◽  
Concrete Mixtures ◽  
Properties Of Materials ◽  
Materials Used

scholarly journals Herpetofauna Distribution and Ecology in East Kutai District, East Kutai, East Kalimantan

2020 ◽  
Vol 5 (8) ◽  
pp. 279-284
Author(s):  
Sus Trimurti ◽  
Andi Sarina ◽  
Lariman .
Keyword(s):  
Diversity Index ◽  
Environmental Parameters ◽  
Microsoft Excel ◽  
Field Orientation ◽  
The Public ◽  
East Kalimantan ◽  
Recorded Data ◽  
Distribution And Ecology ◽  
Index Value ◽  
Number Of Individuals

Herpetofauna consisting of reptiles and amphibians is a group of fauna whose biodiversity potential is rarely known and is not well known by the public. The purpose of this study was to determine the distribution, ecology and diversity of herpetofauna in Mesangat Wetlands. The method used in this research is the Visual Encounter Survey (VES) search method by searching directly for the type of herpetofauna around the predetermined pathway. Field orientation is carried out to determine the location of the observation, the location of the observation is divided into 3 locations (Mesangat Hilir, Tengah and Hulu) in one observation location there are 5 stations (lanes) for herpetofauna observation. Observations were made in the morning starting at 09.00 - 12.00 WITA and at night starting at 20.00 - 23.00 WITA. Recorded data related to the number of individuals, activities, time found, environmental parameters and measured SVL if possible. Identified species were found using the identification key book Field Frogs of Borneo Inger and Stuebing (2014) and A Field Guide to the Snakes of Borneo Stuebing, Inger and Lardner (2014). The data were analyzed using Microsoft Excel 2010. The results showed that the distribution of herpetofauna in Mesangat Wetlands was fairly evenly distributed and the ecology of Mesangat Wetlands supported for herpetofauna life and the diversity index value obtained was 1.53 which was classified as medium category.

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