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Measurement Techniques for Refractive Index and Second-Order Optical Nonlinearities
Published in Hari Singh Nalwa, Seizo Miyata, Nonlinear Optics of Organic Molecules and Polymers, 2020
Toshiyuki Watanabe, Hari Singh Nalwa, Seizo Miyata
Refractive index is one of the most important parameters in determining the nonlinear optical susceptibilities as well as in designing optical waveguides, because the propagation of waves is dominated by the refractive index of a substrate, waveguide layer and over layers. Furthermore, the conversion efficiency of frequency doubler and coupling efficiency into waveguide is also affected by these factors. A brief definition of refractive index is provided here. When light waves traveling through one medium at a velocity V) enter a second medium at a velocity V2, their direction is changed. The index of refraction (n) of a medium is expressed as the ratio of the velocity of wave in vacuum c to their velocity in the medium and can be expressed as c = zqVj = n2V2. The sine of angle formed by the incident wave and the normal to the surface of separation has the same ratio to the sine of the angle formed by the refracted wave and its normal. This ratio defines n which depends on frequency and can be written as 1 sin = n2 sin ?2where ?! is the angle of incidence and ?2is the angle of refraction made with the normal. The Snell's law of refraction can be expressed by n = sin Oj/sin ?2when the standard medium is air; this is further discussed in the text. Each substance has a different value of refractive index under standard conditions of wavelength, temperature, and pressure. The instrument for measuring the refractive index is called a refractometer. In this section, several techniques used to measure the refractive index are discussed.
Costs Associated with the Use of Metalworking Fluids
Published in Jerry P. Byers, Metalworking Fluids, Third Edition, 2018
A refractometer can cost $100–$1000, depending on whether you can read an optical scale or need a digital instrument. A refractometer measures the refraction angle for aqueous solutions (the change in direction of the light path when passing through a liquid). Refractometers are available with different scales, either refractive index or various %Brix scales. The instrument is calibrated by placing a sample of tap water on the prism and adjusting the reading to zero. Remember, all our fresh mixes are made using tap water, so plain tap water is a good reference point. Care needs to be taken to avoid getting free-floating oil from the top of the fluid in the sample. The refractive index of the oil is very different from the emulsified mix and will yield a false reading. Either take the sample from the MWF delivery line or use the technique mentioned for obtaining pH readings in order to obtain the sample. The disadvantage of measuring the fluid concentration of the MWF mix with a refractometer is that some of the lubricating oils (way, spindle, transmission) will become emulsified in the fluid mix and give a false, high-concentration reading. Prior to the release of a fluid mix to the plant, a calibration chart of mix concentrations verses refractometer readings is made. This allows anyone using the MWF to check the mix concentration.
Refractometers
Published in Béla G. Lipták, Analytical Instrumentation, 2018
A refractometer measures the refractive index (RI) of a liquid sample. Refractive index is the ratio of the velocity of light in a vacuum to the velocity of light in the material. Refraction of light (angularity change) occurs at the interface of two different mediums, except for perpendicular light incidence: ) RI=N'=V(vacuum)V(material)
Study of propylene glycol thermal degradation by batch distillation process and analysis using ion chromatography
Published in Petroleum Science and Technology, 2022
Barasha Deka, Dana Badi, Ammar Al Helal, Vikas Mahto, Hari Vuthaluru, Ahmed Barifcani
Concentration of propylene glycol solutions extracted from the reflux drum at various time intervals were measured with a digital refractometer. The specific model of this device is designed only for propylene glycol and is capable of measuring glycol concentration in presence of water, where there should not be any impurities (Al Helal et al. 2018). For every sample, 2–3 drops were extracted and allowed to get cooled to the ambient temperature. Then the drops were placed over the metal sample stage and readings were obtained within 2–3 seconds by eliminating the external light interference. Ideally this distillation system requires reinjection of the extracted liquid into the reflux drum to maintain equilibrium. However, the amount extracted is very small (∼0.8 cc) and to avoid contamination and air injection into the system, this part was omitted. The data were recorded with the refractometer are repeatable with an error bar of ± 0.15% to ± 0.2%.
Solubility parameter of oils by several models and experimental oil compatibility data: implications for asphaltene stability
Published in Petroleum Science and Technology, 2019
David C. Santos, Sofia D. Filipakis, Eduardo R. A. Lima, Márcio L. L. Paredes
The experimental refractive index of crude oils (RI) were measured with an automatic refractometer (Rudolph Research Analytical model J357). The temperature of the refractometer was controlled to ± 0.01 K. The accuracy of the measurement is ± 0.00004 for RI values from 1.29 to 1.70. In Supplementary Material can be found the strategy used to calculate the boiling points (Tb) for crude oils, as well as the methods used to estimate critical temperatures (Tc), critical pressures (Pc) and molar masses (M) of crude oils A to E.
Neuromuscular performance after rapid weight loss in Olympic-style boxers
Published in European Journal of Sport Science, 2020
Damir Zubac, Boštjan Šimunič, Alex Buoite Stella, Shawnda A. Morrison
The urine samples provided by the boxers were analysed (in duplicate) to determine USG values in agreement with the ACSM hydration testing guidelines (Sawka et al., 2007) (AtagoPal-10s refractometer, Tokyo, Japan). The refractometer was calibrated with distilled water before use and provides accurate readings to the 0.001 unit.