Near-infrared Spectral Features Research Articles

Oil and Fat Classification by Selected Bands of Near-Infrared Spectroscopy

One hundred and four edible oil and fat samples from 18 different sources, either vegetable (Brazil nut, coconut, corn, sunflower, walnut, virgin olive, peanut, palm, canola, soybean, sunflower) or animal (tallow and hydrogenated fish), have been analyzed by high-performance gas chromatography (HPGC) and near-infrared spectroscopy (NIRS). Fatty acids were quantified by HPGC. The near-infrared spectral features of the most noteworthy bands were studied and discussed to design a filter-type NIR instrument. An arborescent structure, based on stepwise linear discriminant analysis (SLDA), was built to classify the samples according to their sources. Seven discriminant functions permitted a successive discrimination of saturated fats, corn, soybean, sunflower, canola, peanut, high oleic sunflower, and virgin olive oils. The discriminant functions were based on the absorbance values, between three and five, from the 1700–1800 and 2100–2400 nm regions. Chemical explanations are given in support of the selected wavelengths. The arborescent structure was then checked with a test set, and 90% of the samples were correctly classified.

Near-Infrared Spectroscopy for Monitoring the p-Diethylbenzene Separation Process

Near-infrared (NIR) spectroscopy has been successfully used for the monitoring of important components in the p-diethylbenzene (PDEB) separation process. The process is composed of mostly diethylbenzene isomers ( ortho, meta, and para) and extractant ( p-xylene), as well as other C9–C11 aromatic hydrocarbons. Therefore, the major concern in using NIR spectroscopy in this process was the spectral resolution of NIR spectra among diethylbenzene isomers, since the molecular structures of each isomer were very similar. NIR spectral features of o-diethylbenzene (ODEB), m-diethylbenzene (MDEB), and PDEB showed considerable spectral differences in the 2100–2220 nm range. These combination bands originated from the combination of the =C–H stretch at 3100–3000 cm−1 and C=C ring stretch at 1600–1450 cm−1. Characteristic C=C ring stretches of each isomers in the IR region result in selective and identifiable spectral features in the NIR region. Partial least-squares (PLS) regression was used to build each calibration model for ODEB, MDEB, PDEB, and p-xylene (PX). PLS calibration results of the four components showed excellent correlation with gas chromatography data. The combination region (2100–2500 nm) provided the important isomeric spectral information for PLS calibration since the absorption bands in this region were the most sensitive and selective.

A Near-Infrared Spectroscopic Study of 60 Micron Peakers

We present near-infrared (NIR) spectroscopy of a sample of IRAS-selected galaxies with warm far-infrared colors and spectral energy distributions peaking near 60 ?m. Of the 21 60 ?m peakers classified by optical spectroscopy as Seyfert 2 galaxies, we confirm the existence of dust-obscured broad lines in four (Mkn 3, Mkn 1210, Mkn 463, IRAS 20460). We also propose that two additional 60 ?m peakers may have weak broad lines in the NIR (UGC 02024, IRAS 06488), but we require higher quality data for confirmation. All four of the 60 ?m peakers with confirmed broad NIR lines are known to have broad lines in polarized light, while the two possible candidates have not been observed with spectropolarimetry so far as we are aware. These would be good candidates for future spectropolarimetric observations on large telescopes. Within our sample of 60 ?m peakers, the average ratio of He I/Br? is larger for the starburst galaxies relative to the Seyferts. This is consistent with an evolutionary scenario for 60 ?m peakers, with the starburst class representing an early phase of evolution following an interaction event and the Seyfert class representing a later stage in which the nuclear starburst has faded and has either collapsed to form a central black hole or at least to fuel an existing one. The He I/Br? ratio for the starburst class of 60 ?m peakers is typical of a young starburst with a burst age less than 5 Myr, which is in agreement with their optical spectra. Various near-infrared spectroscopic features ([Fe II]/Pa?, K-band continuum shape, CO absorption, and line widths) are generally consistent with their optical spectroscopic classifications. The exceptions are: IRAS 00160, IRAS 08007A, and IRAS 10567, which are classified as starburst via optical spectroscopy, yet some of their NIR spectral features point toward the existence of a dust-obscured AGN. The stellar absorption CO feature, an indicator of star formation, is detected more strongly in the starburst 60 ?m peakers compared to the Seyfert class, presumably because of dilution by hot dust emission from the active nucleus in the Seyfert 60 ?m peakers.

Evolutionary Synthesis Modeling of Red Supergiant Features in the Near‐Infrared

We present evolutionary synthesis models applied to near-infrared spectral features observed in the spectra of young Magellanic Cloud clusters and starburst galaxies. The temporal evolution of the first and second overtones of CO at 2.29 μm (2-0 band head) and 1.62 μm (6-3 band head) and of the U-B, B-V, and J-K colors are investigated. We find that the current evolutionary tracks of massive stars with subsolar chemical composition in the red supergiant phase are not reliable for any synthesis of the temporal evolution of infrared stellar features. The high sensitivity of the selected infrared features to the atmospheric parameters of cool stars allows us to place constraints on the temperature and the fraction of time spent in the red part of the Hertzsprung-Russell diagram by massive stars during their core helium burning phase. We derive a set of empirically calibrated spectrophotometric models by adjusting the red supergiant parameters so that the properties of the observed templates are reproduced.

Near infrared studies of styrene-sodium methacrylate ionomers

Near Infrared (NIR) spectroscopy coupled with chemometrics techniques were utilized to study the composition and properties of styrene-sodium methacrylate ionomers. Predictive models were obtained for mol % ionic content, as well as for the ionic cluster glass transition temperature, storage modulus, and tan δ peak parameters. The results illustrate the feasibility of using NIR and chemometrics algorithms as a property predictive tool, as well as the potential for the development of full calibration models. The chemometric parameters are discussed based on correlations with ionomer NIR spectral features and the role water molecules play as a probe for the associated structure of the ionomer.

Near-infrared time-resolved spectroscopy of the cataclysmic variable YY Draconis

view Abstract Citations (35) References (52) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-Infrared Time-resolved Spectroscopy of the Cataclysmic Variable YY Draconis Mateo, Mario ; Szkody, Paula ; Garnavich, Peter Abstract Time-resolved near-infrared (8100-8600 A) spectrophotometry and Johnson B-band CCD photometry of the cataclysmic binary YY Dra are presented. The spectra show the presence of the Na I doublet in absorption from the secondary, as well as sharp and broad Ca II emission lines. The sharp Ca II emission lines appear to originate on or near the secondary star because they are visible only during superior conjunction of the secondary star, their radial velocities vary in phase with the Na I absorption lines, and their K-velocity is considerably smaller than observed for the Na I lines. The radial velocity variation of the Na I near-infrared doublet yield an orbital period for YY Dra of P = 0.164988 + or - 0.00023 days. A spectral type of dM 4 + or - 1 for the secondary star is deduced based on the strength of its near-infrared spectral features. The distance to YY Dra is 155 + or - 35 pc based on an application of Bailey's method. Publication: The Astrophysical Journal Pub Date: March 1991 DOI: 10.1086/169823 Bibcode: 1991ApJ...370..370M Keywords: Astronomical Spectroscopy; Binary Stars; Cataclysmic Variables; Line Spectra; Near Infrared Radiation; Astronomical Photometry; Charge Coupled Devices; Dwarf Stars; Emission Spectra; Radial Velocity; Astrophysics; CA II EMISSION; STARS: BINARIES; STARS: DWARF NOVAE; STARS: INDIVIDUAL CONSTELLATION NAME: YY DRACONIS full text sources ADS | data products SIMBAD (5)

Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

Airborne imaging spectrometer data collected in the near-infrared (1.2–2.4 μm) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure—the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration.

Prediction of gasoline octane numbers from near-infrared spectral features in the range 660-1215 nm

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPrediction of gasoline octane numbers from near-infrared spectral features in the range 660-1215 nmJeffrey J. Kelly, Clyde H. Barlow, Thomas M. Jinguji, and James B. CallisCite this: Anal. Chem. 1989, 61, 4, 313–320Publication Date (Print):February 15, 1989Publication History Published online1 May 2002Published inissue 15 February 1989https://doi.org/10.1021/ac00179a007RIGHTS & PERMISSIONSArticle Views1172Altmetric-Citations207LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (944 KB) Get e-Alerts Get e-Alerts

Near-infrared luminosity-sensitive features in M dwarfs and giants, and in M31 and M32

view Abstract Citations (87) References (27) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-infrared luminosity-sensitive features in M dwarfs and giants, and in M31 and M32. Cohen, J. G. Abstract Observations are presented of prominent near-infrared spectral features in M dwarfs and M giants which elucidate the behavior of these features (8183-8195-A doublet of Na I, the Ca II triplet, 9910-A FeH band, and TiO bands) as a function of luminosity and effective temperature. These spectral features have been measured from near-infrared spectra of the nuclei of M31 and M32. A luminosity function similar to that of the solar neighborhood is supported by the observations. The measurements indicate an enhancement of metallicity in the nucleus of M31 as compared with that of M32. Publication: The Astrophysical Journal Pub Date: May 1978 DOI: 10.1086/156081 Bibcode: 1978ApJ...221..788C Keywords: Andromeda Galaxy; Dwarf Stars; Infrared Spectra; M Stars; Near Infrared Radiation; Red Giant Stars; Stellar Luminosity; Abundance; Galactic Evolution; Stellar Spectra; Stellar Spectrophotometry; Astrophysics; Galactic Nuclei:Luminosity Function; Galaxies:Stellar Content; Infrared Spectra:M Dwarfs; Infrared Spectra:M Giants full text sources ADS | data products SIMBAD (23) NED (2)

A Search for Limonite Near-Infrared Spectral Features on Mars

Mars disk intensity, noting spectrophotometric measurements in search for limonite near IR SPECTRAL features