Resolution of Raman spectra of aqueous sulfuric acid mixtures using principal factor analysis

1981 ◽  
Vol 59 (17) ◽  
pp. 2591-2598 ◽  
Author(s):  
Robin A. Cox ◽  
Ülo L. Haldna ◽  
K. Loralee Idler ◽  
Keith Yates
Keyword(s):  
Factor Analysis ◽  
Sulfuric Acid ◽  
Raman Spectra ◽  
Ion Pair ◽  
Medium Composition ◽  
Principal Factor ◽  
Water Molecules ◽  
Concentrated Solutions ◽  
Principal Factor Analysis ◽  
Hydrated Ion

Principal factor analysis has been applied to Raman spectra of 26 sulfuric acid/water mixtures covering the 0–100% H2SO4 concentration range. The analysis greatly facilitates the identification of peaks due to different species. The results show that SO42− ions and "free" HSO4− ions do not co-exist with undissociated H2SO4 molecules in solution and that two water molecules rather than one are required for the first ionization of H2SO4. A species with the composition H2SO4•2H2O, assigned a hydrated ion pair structure, reaches maximum concentration at the same medium composition at which SO42−, free HSO4−, and H2SO4 are at concentration minima, about 75% w/w. The only species apparent in the more concentrated solutions are the ion pair and undissociated H2SO4, which could be taken to mean that H2SO4 is a weaker acid than H3O+, but a stronger one than H3O+•H2O (or H5O2+, if this entity has a real existence). Separate peaks due to the postulated H3O+•H2SO4 (or H5SO5+) were not observed.

Raman Spectroscopy and Factor Analysis of Tumorigenic and Non-Tumorigenic Cells

2002 ◽  
Vol 56 (7) ◽  
pp. 813-819 ◽  
Author(s):  
Kristin M. Omberg ◽  
Jill C. Osborn ◽  
Shuliang L. Zhang ◽  
James P. Freyer ◽  
Judith R. Mourant ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Factor Analysis ◽  
Raman Spectra ◽  
Cell Lines ◽  
Tumor Formation ◽  
Principal Factor ◽  
Phospholipid Content ◽  
Spectral Processing ◽  
Principal Factor Analysis ◽  
Relative Contribution

Raman spectra, measured for viable suspensions of M1 and MR1 cells, demonstrate spectral differences correlating with an increased protein and phospholipid content relative to DNA in the MR1 cells. The M1 and MR1 cell lines consist of rat fibroblast cells that have been transfected with a gene causing immortality, and the MR1 line has been further transfected with a gene causing tumor formation. The cell suspensions were prepared from monolayer cultures in the same phase of growth and remained viable throughout the experiment. The Raman data have been further examined by principal factor analysis with two approaches, (1) a constrained analysis to provide a relative contribution to the Raman data from cellular components, and (2) analysis of differences in the raw data files of the two cell lines. Utilizing the constrained principal factor analysis for the two cell lines analyzed separately provides a measure of the relative contribution of protein, lipid, DNA, RNA, and buffer to the cell Raman spectra. Factor analysis of M1 and MR1 Raman spectra analyzed together demonstrates that the two cell lines can be differentiated by Raman spectroscopy with no prior spectral processing.

Use of principal factor analysis to generate a corn silage fermentative quality index to rank well- or poorly preserved forages

2015 ◽  
Vol 96 (5) ◽  
pp. 1686-1696 ◽  
Author(s):  
Antonio Gallo ◽  
Gianluca Giuberti ◽  
Sara Bruschi ◽  
Paola Fortunati ◽  
Francesco Masoero
Keyword(s):  
Factor Analysis ◽  
Quality Index ◽  
Principal Factor ◽  
Corn Silage ◽  
Principal Factor Analysis

A robust version of principal factor analysis

COMPSTAT ◽  
2000 ◽  
pp. 385-390 ◽  
Author(s):  
G. Pison ◽  
P. J. Rousseeuw ◽  
P. Filzmoser ◽  
C. Croux
Keyword(s):  
Factor Analysis ◽  
Principal Factor ◽  
Principal Factor Analysis ◽  
Robust Version

Revision of the Brief Index of Self-Actualization

1998 ◽  
Vol 87 (1) ◽  
pp. 115-125 ◽  
Author(s):  
John R. Sumerlin ◽  
Charles M. Bundrick
Keyword(s):  
Factor Analysis ◽  
Principal Factor ◽  
Oblique Rotation ◽  
Principal Factor Analysis ◽  
Factor Loadings ◽  
Self Actualization

Items from the 40-item Brief Index of Self-actualization were submitted to principal factor analysis with promax and oblique rotation ( N = 620). With eigenvalues greater than 1 and factor loadings of .40 or higher, 32 items were retained as four factors, without overlap. A revised Brief Index of Self-actualization is presented as an improved measure of constructs underlying Abraham Maslow's description of a self-actualizing person.

Factor analysis for isolation of the Raman spectra of aqueous sulfuric acid components

1984 ◽  
Vol 56 (4) ◽  
pp. 778-781 ◽  
Author(s):  
Edmund R. Malinowski ◽  
Robin A. Cox ◽  
Ulo L. Haldna
Keyword(s):  
Factor Analysis ◽  
Sulfuric Acid ◽  
Raman Spectra ◽  
Aqueous Sulfuric Acid
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