Beyond Beer’s Law: Quasi-Ideal Binary Liquid Mixtures

2021 ◽  
pp. 000370282110562
Author(s):  
Thomas G. Mayerhöfer ◽  
Oleksii Ilchenko ◽  
Andrii Kutsyk ◽  
Jürgen Popp
Keyword(s):  
Principal Components ◽  
Principal Component ◽  
Liquid Mixtures ◽  
Attenuated Total Reflection ◽  
Correlation Spectroscopy ◽  
Multivariate Curve Resolution ◽  
Curve Resolution ◽  
Benzene Toluene ◽  
The Individual ◽  
Spectral Ranges

We have recorded attenuated total reflection infrared spectra of binary mixtures in the (quasi-)ideal systems benzene–toluene, benzene–carbon tetrachloride, and benzene–cyclohexane. We used two-dimensional correlation spectroscopy, principal component analysis, and multivariate curve resolution to analyze the data. The 2D correlation proves nonlinearities, also in spectral ranges with no obvious deviations from Beer’s approximation. The number of principal components is much higher than two and multivariate curve resolution carried out under the assumption of the presence of a third component, results in spectra which only show bands of the original components. The results negate the presence of third components, since any complex should have lower symmetry than the individual molecules and thus more and/or different infrared-active bands in the spectra. Based on Lorentz–Lorenz theory and literature values of the optical constants, we show that the nonlinearities and additional principal components are consequences of local field effects and the polarization of matter by light. Lorentz–Lorenz theory is, however, not able to explain, for example, the different blueshifts of the strong A2u band of benzene in the three mixtures. Obviously, infrared spectroscopy is sensitive to the short-range order around the molecules, which changes with content, their shapes, and their anisotropy.

scholarly journals Study of Chemical Intermediates by Means of ATR-IR Spectroscopy and Hybrid Hard- and Soft-Modelling Multivariate Curve Resolution-Alternating Least Squares

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Junxiu Ma ◽  
Juan Qi ◽  
Xinyu Gao ◽  
Chunhua Yan ◽  
Tianlong Zhang ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Least Squares ◽  
Principal Components ◽  
Energetic Materials ◽  
Comparison Method ◽  
Attenuated Total Reflection ◽  
Alternating Least Squares ◽  
Multivariate Curve Resolution ◽  
Synthesis Process ◽  
Curve Resolution

3,5-Diamino-1,2,4-triazole (DAT) became a significant energetic materials intermediate, and the study of its reaction mechanism has fundamental significance in chemistry. The aim of this study is to investigate the ability of online attenuated total reflection infrared (ATR-IR) spectroscopy combined with the novel approach of hybrid hard- and soft-modelling multivariate curve resolution-alternating least squares (HS-MCR) analysis to monitor and detect changes in structural properties of compound during 3,5-diamino-1,2,4-triazole (DAT) synthesis processes. The subspace comparison method (SCM) was used to obtain the principal components number, and then the pure IR spectra of each substance were obtained by independent component analysis (ICA) and HS-MCR. The extent of rotation ambiguity was estimated from the band boundaries of feasible solutions calculated using the MCR-BANDS procedure. There were five principal components including two intermediates in the process in the results. The reaction rate constants of DAT formation reaction were also obtained by HS-MCR. HS-MCR was used to analyze spectroscopy data in chemical synthesis process, which not only increase the information domain but also reduce the ambiguities of the obtained results. This study provides the theoretical basis for the optimization of synthesis process and technology of energetic materials and provides a strong technical support of research and development of energy material with extraordinary damage effects.

scholarly journals Feed efficiency of lactating Holstein cows is less reproducible when changing dietary starch and fibre concentrations than within diet over subsequent lactation stages

2021 ◽  
Author(s):  
Amélie Fischer ◽  
Philippe Gasnier ◽  
Philippe Faverdin
Keyword(s):  
Principal Components ◽  
Feed Efficiency ◽  
Nir Spectroscopy ◽  
Principal Component ◽  
Holstein Cows ◽  
Diet Change ◽  
Total Variability ◽  
The One ◽  
The Individual ◽  
Starch Diet

ABSTRACTBackgroundImproving feed efficiency has become a common target for dairy farmers to meet the requirement of producing more milk with fewer resources. To improve feed efficiency, a prerequisite is to ensure that the cows identified as most or least efficient will remain as such, independently of diet composition. Therefore, the current research analysed the ability of lactating dairy cows to maintain their feed efficiency while changing the energy density of the diet by changing its concentration in starch and fibre. A total of 60 lactating Holstein cows, including 33 primiparous cows, were first fed a high starch diet (diet E+P+), then switched over to a low starch diet (diet E−P−). Near infra-red (NIR) spectroscopy was performed on each individual feed ingredient, diet and individual refusals to check for sorting behaviour. A principal component analysis (PCA) was performed to analyse if the variability in NIR spectra of the refusals was explained by the differences in feed efficiency.ResultsThe error of reproducibility of feed efficiency across diets was 2.95 MJ/d. This error was significantly larger than the errors of repeatability estimated within diet over two subsequent lactation stages, which were 2.01 MJ/d within diet E−P− and 2.40 MJ/d within diet E+P+. The coefficient of correlation of concordance (CCC) was 0.64 between feed efficiency estimated within diet E+P+ and feed efficiency estimated within diet E−P−. This CCC was smaller than the one observed for feed efficiency estimated within diet between two subsequent lactation stages (CCC = 0.72 within diet E+P+ and 0.85 within diet E−P−). The first two principal components of the PCA explained 90% of the total variability of the NIR spectra of the individual refusals. Feed efficiency was poorly correlated to those principal components, which suggests that feed sorting behaviour did not explain differences in feed efficiency.ConclusionsFeed efficiency was significantly less reproducible across diets than repeatable within the same diet over subsequent lactation stages, but cow’s ranking for feed efficiency was not significantly affected by diet change. The differences in sorting behaviour between cows were not associated to feed efficiency differences in this trial neither with the E+P+ diet nor with the E−P− diet. Those results have to be confirmed with cows fed with more extreme diets (for example roughage only) to ensure that the least and most efficient cows will not change.

Probing Membrane Fouling via Infrared Attenuated Total Reflection Mapping Coupled with Multivariate Curve Resolution

ChemPhysChem ◽  
2016 ◽  
Vol 17 (3) ◽  
pp. 358-363 ◽  
Author(s):  
Wei Chen ◽  
Xiao-Yang Liu ◽  
Bao-Cheng Huang ◽  
Long-Fei Wang ◽  
Han-Qing Yu ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Multivariate Curve Resolution ◽  
Curve Resolution

scholarly journals Critical Evaluation of Spectral Resolution Enhancement Methods for Raman Hyperspectra

2021 ◽  
pp. 000370282110611
Author(s):  
H. Georg Schulze ◽  
Shreyas Rangan ◽  
Martha Z. Vardaki ◽  
Michael W. Blades ◽  
Robin F. B. Turner ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Spectral Resolution ◽  
Resolution Enhancement ◽  
Critical Evaluation ◽  
Principal Component ◽  
Hyperspectral Data ◽  
Correlation Spectroscopy ◽  
Multivariate Curve Resolution ◽  
Peak Fitting ◽  
Overlapping Peaks

Overlapping peaks in Raman spectra complicate the presentation, interpretation, and analyses of complex samples. This is particularly problematic for methods dependent on sparsity such as multivariate curve resolution and other spectral demixing as well as for two-dimensional correlation spectroscopy (2D-COS), multisource correlation analysis, and principal component analysis. Though software-based resolution enhancement methods can be used to counter such problems, their performances often differ, thereby rendering some more suitable than others for specific tasks. Furthermore, there is a need for automated methods to apply to large numbers of varied hyperspectral data sets containing multiple overlapping peaks, and thus methods ideally suitable for diverse tasks. To investigate these issues, we implemented three novel resolution enhancement methods based on pseudospectra, over-deconvolution, and peak fitting to evaluate them along with three extant methods: node narrowing, blind deconvolution, and the general-purpose peak fitting program Fityk. We first applied the methods to varied synthetic spectra, each consisting of nine overlapping Voigt profile peaks. Improved spectral resolution was evaluated based on several criteria including the separation of overlapping peaks and the preservation of true peak intensities in resolution-enhanced spectra. We then investigated the efficacy of these methods to improve the resolution of measured Raman spectra. High resolution spectra of glucose acquired with a narrow spectrometer slit were compared to ones using a wide slit that degraded the spectral resolution. We also determined the effects of the different resolution enhancement methods on 2D-COS and on chemical contrast image generation from mammalian cell spectra. We conclude with a discussion of the particular benefits, drawbacks, and potential of these methods. Our efforts provided insight into the need for effective resolution enhancement approaches, the feasibility of these methods for automation, the nature of the problems currently limiting their use, and in particular those aspects that need improvement.

scholarly journals Analiza dejavnikov ribolovne učinkovitosti v metierjih Severnega Atlantika

2021 ◽  
Author(s):  
Janja Jerebic ◽  
Špela Kajzer ◽  
Anja Goričan ◽  
Drago Bokal
Keyword(s):  
North Atlantic ◽  
Principal Components ◽  
Principal Component ◽  
Fishing Effort ◽  
Human Consumption ◽  
High Complexity ◽  
Fishing Fleets ◽  
The Individual ◽  
Location Type ◽  
Variance Explained

The management of fishing fleets is an important factor in the sustainable exploitation of marine organisms for human consumption. Therefore, regulatory services monitor catches and limit them based on data. In this paper, we analyze North Atlantic Fishing Organization (NAFO) data on North Atlantic catches to direct the effectiveness of fishing stakeholders. Data on fishing time (month and year), equipment, location, type of catch, and, for us, the most interesting, data on the fishing effort are given, and their quality is analyzed. In the last part, The Principal Component Analysis for individual activities, among which fishing stakeholders can decide, is performed on a selected data sample. The complexity of the connections between the set of observed activities is explained by new uncorrelated variables - principal components - that are important for achieving the expected fishing catch. We find that the proportions of variance explained by the individual principal components are low, which indicates the high complexity of the topic discussed.

scholarly journals Characterization of phosphate structures in biochar from swine bones

2012 ◽  
Vol 47 (5) ◽  
pp. 672-676 ◽  
Author(s):  
Etelvino Henrique Novotny ◽  
Ruben Auccaise ◽  
Marcia Helena Rodrigues Velloso ◽  
Juliano Corulli Corrêa ◽  
Martha Mayumi Higarashi ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Principal Component ◽  
Multivariate Curve Resolution ◽  
Resonance Spectroscopy ◽  
Curve Resolution ◽  
Lower Solubility ◽  
Symmetry Properties ◽  
Resolution Analysis ◽  
Alternative Methodology

The objective of this work was to develop an alternative methodology to study and characterize the phosphate crystalline properties, directly associated with solubility and plant availability, in biochar from swine bones. Some phosphate symmetry properties of pyrolyzed swine bones were established, using solid state nuclear magnetic resonance spectroscopy, principal component analysis, and multivariate curve resolution analysis, on four pyrolyzed samples at different carbonization intensities. Increasing carbonization parameters (temperature or residence time) generates diverse phosphate structures, increasing their symmetry and decreasing the crossed polarizability of the pair ¹H-31P, producing phosphates with, probably, lower solubility than the ones produced at lower carbonization intensity. Additionally, a new methodology is being developed to study and characterize phosphate crystalline properties directly associated with phosphate solubility and availability to plants.

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