Method for calculating the properties of hydrocarbons and its application to the refractive indices, densities, and boiling points of the paraffin and monoolefin hydrocarbons

Using multivariational statistical methods, the calculation and interpretation of empirical parameters of the polarity of solvents has been reexamined. The size of the sample used (57 aprotic solvents and 24 protic solvents) assures that it is representative. For each solvent, the data tabulated include some physical constants (dielectric constants, dipole moments, refractive indices, molar refractions, boiling points, Hildebrand's δ parameters) or theoretical values (energy levels of frontier orbitals). The methods used are factorial analysis and multiple regression. The results obtained show that, for the aprotic solvents, the parameter ET is a measure of the polarity, of the polarizability, and of the cohesion of the solvent to the extent of 43, 39, and 18% respectively. For the parameter π*, these proportions are respectively 53, 18, and 29%. For the protic solvents, the parameter ET is explained by the same variables except for 5 solvents more acidic than water; this anomaly is explained by the basicity of the oxygen of the betaine used to define ET.

Download Full-text

The spindle stage: A powerful optical tool

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102341 ◽

1988 ◽

Vol 46 ◽

pp. 52-53

Author(s):

Mickey E. Gunter ◽

F. Donald Bloss

Keyword(s):

Significant Error ◽

Optical Data ◽

Refractive Indices ◽

Axis Of Rotation ◽

Polarizing Microscope ◽

Microscope Stage

A single, reasonably homogeneous, nonopaque 30-to-300 μm crystal, mounted on a spindle stage and studied by immersion methods under a polarizing microscope, yields optical data frequently sufficient to identify and characterize a substance unequivocally. The data obtainable include (1) the orientation of the crystal's principal vibration axes and (2) its principal refractive indices, to within 0.0002 if desired, for light vibrating along these principal vibration axes. Spindle stages tend to be simple and relatively inexpensive, some costing less than $50. They permit rotation of the crystal about a single axis which is parallel to the microscope stage. This spindle or S-axis is thus perpendicular to the M-axis, namely the microscope stage's axis of rotation.A spindle stage excels when studying anisotropic crystals. It orients uniaxial crystals within minutes and biaxial crystals almost as quickly so that their principal refractive indices - ɛ and ω (uniaxial); α, β and γ (biaxial) - can be determined without significant error from crystal misorientation.

Download Full-text

Light microscopy of ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015037x ◽

1993 ◽

Vol 51 ◽

pp. 908-909

Author(s):

Walter C. McCrone

Keyword(s):

Refractive Index ◽

Light Microscopy ◽

Light Microscope ◽

Polarized Light ◽

Refractive Indices ◽

Complete Coverage ◽

The Subject ◽

Lower Refractive Index

An excellent chapter on this subject by V.D. Fréchette appeared in a book edited by L.L. Hench and R.W. Gould in 1971 (1). That chapter with the references cited there provides a very complete coverage of the subject. I will add a more complete coverage of an important polarized light microscope (PLM) technique developed more recently (2). Dispersion staining is based on refractive index and its variation with wavelength (dispersion of index). A particle of, say almandite, a garnet, has refractive indices of nF = 1.789 nm, nD = 1.780 nm and nC = 1.775 nm. A Cargille refractive index liquid having nD = 1.780 nm will have nF = 1.810 and nC = 1.768 nm. Almandite grains will disappear in that liquid when observed with a beam of 589 nm light (D-line), but it will have a lower refractive index than that liquid with 486 nm light (F-line), and a higher index than that liquid with 656 nm light (C-line).

Download Full-text

On electronic polarizabilities and refractive indices in SbSI crystal

Ferroelectrics Letters Section ◽

10.1080/07315178308202119 ◽

1983 ◽

Vol 44 (12) ◽

pp. 349-359

Author(s):

Wataru Kinase ◽

Tadataka Morishita ◽

Yutaka Hiyama ◽

Tomoo Maeda

Keyword(s):

Refractive Indices

Download Full-text

Comparison of physicochemical properties of edible vegetable oils commercially available in Bahir Dar, Ethiopia

10.31221/osf.io/jeabt ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Physicochemical Properties ◽

Vegetable Oils ◽

Relative Viscosity ◽

Acid Value ◽

Smoke Point ◽

Refractive Indices ◽

Bahir Dar ◽

Icp Oes ◽

Saponification Value ◽

Oil Sunflower

The physicochemical properties of six imported and one locally produced edible vegetable oils (soybean oil, sunflower oil, sunlit oil, hayat oil, avena oil, USA vegetable oil and Niger oil) purchased from Bahir Dar city, Ethiopia, were examined for their compositional quality. All the oil samples were characterized for specific gravity, moisture content, color, relative viscosity, refractive indices, ash content, peroxide value, saponification value, smoke point, acid value, free fatty acid value and trace metals contents using established methods. The result clearly indicates that some of the oil samples exhibited unacceptable value when compared with physicochemical parameters recommended by the Codex Alimentations Commission of FAO/WHO and the specification of Ethiopian standards. The contents of nickel (Ni), copper (Cu) and iron (Fe) in seven samples were determined using ICP-OES and their concentrations were found in the range of 1.8-20.4, 45.8-82.2 and 136.04-445.0 mg/kg, respectively.

Download Full-text

Simulation for enhancement in sensitivity of chalcogenide glasses-based fibre optic evanescent absorption sensor for malignant tissue detection

Micro and Nanosystems ◽

10.2174/1876402912999200527141549 ◽

2020 ◽

Vol 12 ◽

Author(s):

Ritesh Kumar Singh ◽

Adarsh Chandra Mishra ◽

Pooja Lohia ◽

D.K. Dwivedi

Keyword(s):

Evanescent Wave ◽

Chalcogenide Glasses ◽

Biological Tissues ◽

Biological Species ◽

Primary Objective ◽

Effect Of Temperature ◽

Refractive Indices ◽

Core Radius ◽

Source Illumination ◽

Study Results

Background: Refractive index determination of biological tissues is a challenging issue. Many biological species also show vibrational signature in infrared domain. The chalcogenide-based glasses can be used to make the fiber optic evanescent wave sensors for detection of analyte. Objectives: The primary objective is to study the effect of various parameters on the sensitivity of chalcogenide glass-based evanescent wave sensor for biological tissue detection. Methods: An evanescent wave sensor has been proposed with collimated source illumination and uniform tapering. The chalcogenide materials are chosen such that the weakly guiding approximation could be followed. Complex refractive indices of liver tissue samples have been taken for the analysis of sensitivity via method of evanescent absorption coefficient. Equations for sensitivity have been solved analytically using MATLAB software. Results: The simplification of the formula for sensitivity leads to the inference that the sensitivity is a function of core radius, refractive indices of sample tissues and wavelength used. Moreover, since the refractive indices of the materials are also a function of temperature, therefore a change in temperature results into change in the profile of guiding mode. Hence the effect of temperature must also be observed. The initial simulation parameters are taken; core radius 100 µm, sensing length 4 cm and wavelength 1.0 µm. In the NIR region we have a better sensitivity of detection for all the tissues samples and the risk of photodamage of the biosamples is reduced to a good extent. It has been found that sensitivity decreases with wavelength and core radius whereas increases with temperature. It has also been shown that sensitivity is found to be better with collimated in comparison with diffused source. Conclusion: The comparative study results that one should operate at shorter NIR region of wavelength for higher sensitivity. The collimated source illumination should be preferred over diffused one for launching the light within the fiber to have high sensitivity. Further, length of sensing region should be larger but the fiber core radius should be smaller. The proposed biosensor is robust and can also be used many times if the probe (sensing region) is cleaned properly. Moreover, a small amount of analyte is enough for the detection. Thus, the proposed sensor is very useful for bio-medical applications with its high performance, accuracy and robustness.

Download Full-text

Application of the turbidity ratio method in the spherical particle size determination in the range m ∈ and α ∈

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19792064 ◽

1979 ◽

Vol 44 (7) ◽

pp. 2064-2078 ◽

Cited By ~ 3

Author(s):

Blahoslav Sedláček ◽

Břetislav Verner ◽

Miroslav Bárta ◽

Karel Zimmermann

Keyword(s):

Refractive Index ◽

Spherical Particle ◽

Ratio Method ◽

Refractive Indices ◽

Relative Refractive Index ◽

Particle Size Determination ◽

The Individual ◽

The Given ◽

Turbidity Ratio ◽

Selection Of

Basic scattering functions were used in a novel calculation of the turbidity ratios for particles having the relative refractive index m = 1.001, 1.005 (0.005) 1.315 and the size α = 0.05 (0.05) 6.00 (0.10) 15.00 (0.50) 70.00 (1.00) 100, where α = πL/λ, L is the diameter of the spherical particle, λ = Λ/μ1 is the wavelength of light in a medium with the refractive index μ1 and Λ is the wavelength of light in vacuo. The data are tabulated for the wavelength λ = 546.1/μw = 409.357 nm, where μw is the refractive index of water. A procedure has been suggested how to extend the applicability of Tables to various refractive indices of the medium and to various turbidity ratios τa/τb obtained with the individual pairs of wavelengths λa and λb. The selection of these pairs is bound to the sequence condition λa = λ0χa and λb = λ0χb, in which b-a = δ = 1, 2, 3; a = -2, -1, 0, 1, 2, ..., b = a + δ = -1, 0, 1, 2, ...; λ0 = λa=0 = 326.675 nm; χ = 546.1 : 435.8 = 1.2531 is the quotient of the given sequence.

Download Full-text

Excess volumes and refractive indices in the benzene-tert-amyl methyl ether and cyclohexane-tert-amyl methyl ether systems at 298.15 K

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19872839 ◽

1987 ◽

Vol 52 (12) ◽

pp. 2839-2843 ◽

Cited By ~ 18

Author(s):

Jan Linek

Keyword(s):

Methyl Ether ◽

Excess Molar Volumes ◽

Excess Volumes ◽

Refractive Indices ◽

Molar Volumes ◽

Vibrating Tube Densimeter ◽

Ether System

Excess molar volumes in the benzene-tert-amyl methyl ether and cyclohexane-tert-amyl methyl ether systems were measured by a vibrating-tube densimeter at 298.15 K and compared with the data for the methanol-tert-amyl methyl ether system determined previously. Besides, the refractive indices in both the systems were measured at the same temperature.

Download Full-text