Authors:M. Leitão, C. Nobre, J. Jesus, and J. Redinha
The study of trans- and cis-1,2-cyclohexanediol by infrared spectroscopy was performed. The variation of the maximum frequency and of the bandwidth of the OH stretching vibration give evidence of the role played by hydrogen bonding in the solid and liquid phases of both isomers and allows to follow the phase transitions. A solid rotator phase is shown for the cis compound.
Authors:A. Păucean, D.C. Vodnar, V. Mureșan, F. Fetea, F. Ranga, S.M. Man, S. Muste, and C. Socaciu
, F. , He , Y. , Wang , L. & Sun , G. ( 2011 ): Detection of organic acids and pH of fruit vinegars using near-infraredspectroscopy and multivariate calibration . Food Bioprocess Tech. , 4 , 1331 – 1340
Authors:Botond Szucs, Mate Petrekanits, Monika Fekete, and Janos T Varga
near-infraredspectroscopy (NIRS), is able to non-invasively provide information about these changes in oxygenation and hemodynamics in muscle tissue based on the oxygen-dependent characteristics of near-infrared light. NIRS has been utilized to
Authors:M. Leităo, J. Canotilho, A. Sousa, A. Pais, A. Sousa, and J. Simőes Redinha
In this paper the structural characterization of terfenadine crystallized from ethanol-water, ethanol and methanol is performed
by infrared spectroscopy. The OH stretching vibration, composed of three markedly overlapped bands, is analyzed by peak fitting.
The assignment of the hydrogen bonds was conducted making use of band parameters, spectroscopic data for CCl4 solutions, and molecular dynamics calculations from dimeric systems. Terfenadine just precipitated from solvents is never
in the highest crystalline state. This state is reached when the samples are heated at a temperature above 100C. Some amorphous
solid is coprecipitated with the crystalline phase, particularly in methanol.
This paper presents and interprets photoacoustic (PA) infrared spectra and four different thermophysical properties (thermal conductivity, thermal diffusivity, volumetric specific heat and thermal effusivity) for four sets of hydrocarbon cokes. A total of 12 samples, with varying histories, were analyzed. These cokes are a by-product of the upgrading of bitumen to Syncrude Sweet Blend (a blend of hydrotreated components), and were obtained from several locations in the thermal cokers operated by Syncrude Canada Ltd. in Fort McMurray, Alberta, Canada. PA infrared spectroscopy provides detailed information on the amount and type of residual aromatic hydrocarbons in cokes; aliphatic hydrocarbons are sometimes detected in smaller quantities. Three of the thermophysical properties (thermal conductivity, diffusivity and effusivity) display systematic differences among the cokes. On the other hand, volumetric specific heat hardly varies, a phenomenon that accounts for the observed proportionality between thermal diffusivity and conductivity. Analogous relationships exist between thermal effusivity and both thermal conductivity and thermal diffusivity for these cokes. The magnitudes of these three thermophysical properties tend to increase as aromatics contents, determined by PA spectroscopy, decrease.
Although thermogravimetric analysis (TG) has become an indispensable tool for the analysis and characterization of materials,
its scope is limited as no information is obtained about the qualitative aspects of the evolved gases during the thermal decomposition.
For processes involving mass loss, a powerful technique to provide this missing information is Fourier transform infrared
spectroscopy (FT-IR) in combination with TG. It supplies a comprehensive understanding of thermal events in a reliable and
meaningful way as data are obtained from a single sample under the same conditions.
The coupling TG/FT-IR is used in fuel analysis for the identification of residual volatiles, to determine their sequence of
release and to resolve thermogravimetric curves. In this work, the usefulness of TG/FT-IR for characterizing middle distillate
fuel residues is illustrated with some typical examples of recent application. A Bio-Rad FTS 25 FT-IR spectrometer coupled
with a TA Instruments TGA 2950 thermogravimetric analyzer was used for data aquisition.
The results obtained demonstrate the utility of this combined technique in determining the decomposition pathway of tarry
materials at various stages of pyrolysis, thereby allowing new insights into the complex thermal behaviour of hydrocarbon
Authors:S. Cebulak, A. Matuszewska, and A. Langier-Kuźniarowa
The paper presents the applicability of oxyreactive thermal analysis (OTA) for the investigation of different kinds of resins
both natural (recent and fossil) and synthetic. For comparative reasons and a more precise interpretation, along with OTA
infrared spectroscopy was used as a method commonly applied for the investigation of fossil resins. The results obtained prove
that the OTA method may be very useful for diversification of different kinds of resins. The parameter most valuable for the
preliminary characteristics of resins and the evaluation of their transformation was found to be the mass loss recorded on
TG curves in three definite temperature ranges.
Authors:Marina Vranić, Mladen Knežević, Zsolt Seregély, Krešimir Bošnjak, Josip Leto, and Goran Perčulija
Blanco, M., Coello, J., Iturriaga, H., Maspoch, S., Gonzalez, R. (1998) Determination of water in lubricating oils by mid- and near-infraredspectroscopy. Microchim. Acta 128: 235.
Determination of water in lubricating oils by