Determination of Copolymer Composition by Combustion Analysis for Carbon and Hydrogen

1960 ◽  
Vol 33 (4) ◽  
pp. 1132-1141
Author(s):  
Lawrence A. Wood ◽  
Irving Madorsky ◽  
Rolf A. Paulson
Keyword(s):  
Refractive Index ◽  
Present Method ◽  
Copolymer Composition ◽  
Combustion Analysis ◽  
Physical Methods ◽  
Accuracy And Precision ◽  
Styrene Content ◽  
The One ◽  
Relative Measurements

Abstract The procedure described attains its accuracy and precision by the refinement and improvement of conventional simple operations over a periods of years. The trend in analysis recently is, of course, toward the use of rapid physical methods. In a great many instances these involve relative measurements requiring the initial establishment of reference materials with compositions determined by methods such as the one here described, which bases the numbers derived solely on readings of an analytical balance. In fact, as already mentioned, one of the principal applications of the present method has been in the establishment of the relation between refractive index and styrene content for SBR polymers so that refractive index measurements can be used in routine determinations of bound styrene content.

A Modified Semi-automated Resorcinol Method for the Determination of Inulin

1969 ◽  
Vol 15 (11) ◽  
pp. 1072-1078 ◽  
Author(s):  
Thomas H Steele
Keyword(s):  
Present Method ◽  
Protein Precipitation ◽  
Accuracy And Precision ◽  
Precipitation Procedure ◽  
High Degree ◽  
Automated Methods ◽  
Resorcinol Method ◽  
Urine Specimens

Abstract A semi-automated resorcinol method for the determination of inulin in plasma and urine specimens, using standard AutoAnalyzer modules, is described. Plasma and other protein-containing fluids undergo a preliminary manual protein precipitation procedure. The deproteinized specimens are processed at a rate of 50/hr, with a high degree of accuracy and precision. The superiority of the present method is largely due to the elimination of small acid-resistant pump tubes from the manifold. This is possible because reagents are premixed prior to aspiration into the system, allowing simplification of manifold design over other automated methods.

REFRACTIVE INDEX OF He4: LIQUID

1958 ◽  
Vol 36 (7) ◽  
pp. 884-898 ◽  
Author(s):  
M. H. Edwards
Keyword(s):  
Refractive Index ◽  
Experimental Error ◽  
Saturated Vapor ◽  
Liquid Density ◽  
Phase Index ◽  
Vertical Tangent ◽  
Group Refractive Index ◽  
Relative Measurements ◽  
Λ Point

Changes in the phase refractive index n with temperature have been measured between 1.6 and 4.2° K at λ = 5462.27 Å, for liquid He4 at its saturated vapor pressure, using a metal optical cryostat and a Jamin interferometer. A novel adaptation of the Jamin interferometer has been made so that, in addition, an absolute determination of the group refractive index, nG, could be made using white light of "effective wavelength" 5595 ± 40 Å. When the dispersion correction is made, the phase index for the Hg green line at T55E = 3.700° K is n = 1.026124 ± 0.000035. The relative measurements have been adjusted to this value. The more than 200 experimental points show a random scatter of less than 5 × 10−6 in index. Using Kerr's density data the polarizability is thus (N0α) = (0.12454 ± 0.00021) cm3 mole−1 at λ = 5462.27 Å, for liquid He4 at 3.7 °K. Within experimental error (N0α) is found to be independent of temperature. Thus the refractive index data may be considered as a measurement of the liquid density and coefficient of expansion.The region near the λ-point is of special interest. The expansion coefficient determined from the refractive index, βn, may be represented within experimental error by 103βnI = +41.5 + 14.5 log|T−Tλ| for T > Tλ, from about 0.1° above Tλ to within 0.01° of Tλ; and by 103βnII = −1.5 + 14.5 log |T−Tλ| for T < Tλ, from about 0.1° below Tλ to within 0.002° of Tλ. This implies that the density–temperature curve has both a vertical tangent and a point of inflection at the λ-point; and that the maximum in density occurs about 0.001° above the λ-point.

scholarly journals Validation of UV Spectrophotometry Method for Determination of Lopinavir and Ritonavir Simultaneously

2021 ◽  
Vol 8 (2) ◽  
pp. 48
Author(s):  
Siti Umi Anisah ◽  
Asri Darmawati ◽  
Amirudin Prawita
Keyword(s):  
Method Validation ◽  
Simultaneous Equation ◽  
Uv Spectrophotometry ◽  
First Derivative ◽  
Accuracy And Precision ◽  
Significant Difference ◽  
The Mean ◽  
The One ◽  
One Way Anova

Lopinavir and ritonavir are anti-viral compounds that have similar chemical structures and overlapping UV spectral profiles. The combination of these two compounds is being promoted as an anti-COVID19 drug. Determination of these two compounds simultaneously using UV spectrophotometry method requires special technique so that the result will be valid. The purpose of this study was to obtain a suitable analytical technique using UV spectrophotometry for the determination of lopinavir-ritonavir simultaneously that fulfill the method validation requirement. In this study, the simultaneous equation technique, absorptivity comparison factor, and first derivative technique were used to overcome the effect of lopinavir/ritonavir absorbance at selected wavelengths for determination of each compound simultaneously. The one-way ANOVA statistical test was used to compare the result of the three analytical techniques. The results showed that the three techniques fullfilled the AOAC requirements for selectivity and linearity. The accuracy and precision test result have not met the requirements of the AOAC method validation. Statistically. the one-way ANOVA analysis showed there was a significant difference between the mean recovery of lopinavir using the absorptivity factor and first derivative technique. Whereas, there was no significant differences among the mean of ritonavir recoveries that were determined using those three techniques. As conclusion, that the UV spectrophotometric method using the simultaneous equation technique, the absorptivity factor technique, and the derivative technique for assaying the lopinavir and ritonavir simultaneously met the requirements for selectivity and linearity parameters. However, the accuracy and precision have not met the requirements. The first derivative technique is suitable for further developed for ritonavir and lopinavir determination simultaneously

Laser Deflection Measurements for the Determination of Temperature and Charge Carrier Distributions in 4H-SiC Power Diodes

2009 ◽  
Vol 615-617 ◽  
pp. 267-270 ◽  
Author(s):  
Dorothea Werber ◽  
Gerhard Wachutka
Keyword(s):  
Refractive Index ◽  
Charge Carrier ◽  
Current Flow ◽  
Spatial Modulation ◽  
Carrier Injection ◽  
The Real ◽  
Power Diodes ◽  
The One ◽  
Real Refractive Index

A change of the electron and hole densities n and p and of the lattice temperature T modulates the real optical refractive index nopt of the device under test. In the forward conducting state the electron and hole distributions n(x) and p(x) in the i-region of the device are generated by the action of carrier injection from the n- and p-emitters. The device is locally heated by Joule and recombination heat, leading to a temperature distribution T(x). The gradients of temperature and charge carrier densities cause a spatial modulation of the real refractive index nopt(x). A laser beam transmitted orthogonally to the direction of current flow of the device is deflected by the gradient of nopt(x). Concurrent deflections caused simultaneously by the carrier gradients on the one side and by the temperature gradient on the other side can be discriminated by their different time constants.

scholarly journals Determination of Birefringence of Uniaxial Crystals: The Use of Conoscopy for Quantitative Measurements

1996 ◽  
Vol 4 (5) ◽  
pp. 12-13
Author(s):  
Mohan Srinivasarao
Keyword(s):  
Refractive Index ◽  
Liquid Crystals ◽  
Optical Microscope ◽  
Visual Observation ◽  
Quantitative Measurements ◽  
The One

Often times one is asked the question "how can the optical microscope be used to make quantitative measurements?" The microscope certainly lets one observe the sample {whatever the sample may be) and make qualitative statements about what is it one is looking at. It has been used for various purposes from just visual observation in brightfield, reflection and the one that is near and dear to my heart, observations under crossed polarizers. This certainly allows one to identify materials as being isotropic or anisotropic. If one works on materials like liquid crystals, an optical microscope is a tool that is used all the time. It certainly allows for identification of various phases of liquid crystals based on the defects and textures that can be observed. All of this is somewhat qualitative in nature. By that I mean that the observations do not lend themselves to obtain, say for example, refractive index or birefringence of the material. I would like to describe a technique that will allow one to do just that.

scholarly journals Holistic Approach to R&D Products’ Evaluation for Commercialization under Open Innovations

2022 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Nataliya Chukhray ◽  
Oleksandra Mrykhina ◽  
Ivan Izonin
Keyword(s):  
Refractive Index ◽  
Marketing Research ◽  
Holistic Approach ◽  
Added Value ◽  
Optical Range ◽  
Crystalline Materials ◽  
Market Effects ◽  
The One

A holistic approach to R&D products’ evaluation for commercialization under open innovations is developed. The approach is tested on the example of the device of the interferometric determination of the refractive index of crystalline materials in the optical range. The proposed approach will allow setting a price that will satisfy all the parties of a transfer agreement with a higher level of accuracy and will meet market requirements. Unlike popular methods of evaluating the R&D product, a holistic approach will, on the one hand, be based on the actual costs and the break-even level of a R&D product and, on the other hand, will determine how much the consumer is receptive to a R&D product, and, then again, will show how the added value of the product will develop under the influence of market effects. It is noted that the application of a holistic approach to R&D products’ evaluation for commercialization should be supplemented by assessing the willingness of potential customers to purchase this R&D product at a specific price. It is proved that the proposed holistic approach to R&D products’ evaluation for commercialization is multifunctional. The approach can be applied to different types of economic activity, R&D products, and types of markets. The obtained prices based on the application of a holistic approach to R&D products’ evaluation for commercialization and the results of marketing research of the interferometry market testified to potential prospects of the commercialization of a R&D product of the interferometric determination of the refractive index of crystalline materials in the optical range and its long-term competitiveness. Based on the results, the key provisions of the concept of providing competitive benefits for the period of implementation of the analyzed R&D product are identified. Taking into account fundamental elements of the open innovation paradigm underpins the authors’ holistic approach.

The Control of Errors in Infrared Spectrophotometry. VI. The Evaluation of Optical Constants by Combined Transmission and Attenuated Total Reflection Measurements

1980 ◽  
Vol 34 (6) ◽  
pp. 652-656 ◽  
Author(s):  
T. G. Goplen ◽  
D. G. Cameron ◽  
R. N. Jones
Keyword(s):  
Refractive Index ◽  
Optical Constants ◽  
Statistical Treatment ◽  
Statistical Error ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Integration Constant ◽  
The One ◽  
Improved Technique

An improved technique is described for the determination of the optical constants of liquids in the infrared. It is based on a combination of transmission and attenuated total reflection (ATR) measurements. A novel application of the Kramers-Kronig transform function is involved whereby a single-valued integration constant is derived from a vector of refractive index measurements obtained by ATR. These are measured over a wavenumber range where the absorbance is low. It has been shown in earlier work that by an appropriate choice of a low refractive index contact material (in our case sodium chloride) the ATR method has high precision and accuracy under these conditions. The accuracy of the method is evaluated on the basis of a statistical treatment of the propagation of the estimated errors in the experimentally measured quantities, viz., the transmittance, the cell thickness, and the ATR measurements which establish the integration constant (anchor point) of the Kramers-Kronig transform function. The transmittance measurements are made at several cell thicknesses. The data reduction computer program, by which the optical constants are evaluated from the transmission measurements, monitors these sets of data and selects at each wavenumber the one having the minimal statistical error.

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