Search results for "Infrared"
showing 10 items of 2110 documents
Model compounds of spent bleach liquor: 2,3,6-trichloro-p-cymenene and 2,3,5-trichloro-p-cymenene
1991
Abstract 2,3,6-Trichloro-p-cymene (1) was synthesized by chlorination of p-cymene. A reaction mixture was distilled in a Fischer-Spaltrohr distilling apparatus. One fraction contained small quantities of chlorinated cymenenes (two isomers) which were concentrated by preparative gas chromatography. Their FTIR and mass spectra were recorded. In earlier paper the structures of 2,3,6-trichloro-p-cymenene were verified by means of its coupled 13C NMR and mass spectra. In the present work the mass and FTIR spectral data of 2,3,5-trichloro-p-cymenene and 2,3,6-trichloro-p-cymenene are published.
Characterization of Hardwood Soda-AQ Lignins Precipitated from Black Liquor through Selective Acidification
2016
In the development of integrated biorefinery process alternatives to produce value-added by-products, various black liquors from sulfur-free pulping processes offer potential feedstocks for recovering their main chemical constituents, lignin and aliphatic carboxylic acids. In this study, lignin fractions were obtained from silver birch (Betula pendula) soda-anthraquinone black liquor by carbonation (pH to about 8.5) or by acidification (pH to about 2) with H2SO4 after carbonation or directly. These fractions were characterized by Fourier transform infrared (FTIR), ultraviolet (UV), energy dispersive X-ray fluorescence (ED XRF), and 13C nuclear magnetic resonance (13C NMR) spectroscopy. In a…
The role of intact oleosin for stabilization and function of oleosomes.
2013
Lipid storage in plants is achieved among all plant species by formation of oleosomes, enclosing oil (triacylglycerides) in small subcellular droplets. Seeds are rich in this pre-emulsified oil to provide a sufficient energy reservoir for growing. The triacylglyceride core of the oleosomes is surrounded by a phospholipid monolayer containing densely packed proteins called oleosins. They are anchored in the triacylglycerides core with a hydrophobic domain, while the hydrophilic termini remain on the surface. These specialized proteins are expressed during seed development and maturation. Particularly, they play a major role in the stabilization and function of oleosomes. To better understand…
Enhancing TIR Image Resolution via Bayesian Smoothing for IRRISAT Irrigation Management Project
2013
Accurate estimation of physical quantities depends on the availability of High Resolution (HR) observations of the Earth surface. However, due to the unavoidable tradeoff between spatial and time resolution, the acquisition instants of HR data hardly coincides with those required by the estimation algorithms. A possible solution consists in constructing a synthetic HR observation at a given time k by exploiting Low Resolution (LR) and HR data acquired at different instants. In this work we recast this issue as a smoothing problem, thus focusing on cases in which observations acquired both before and after time k are available. The proposed approach is validated on a region of interest for t…
Estimation of Daily Solar Radiation from Measured Air Temperature Extremes in the Mid-Mediterranean Area
2012
AbstractDaily solar radiation Rs at ground level is a necessary input variable required for the evaluation of evapotranspiration and crop growth, development, and yield-simulation models. Nevertheless, it is measured in few weather stations and at many locations it is not observed; also, available Rs temporal series are generally no longer than a few years. A valid surrogate of Rs measurement is the diurnal air-temperature range (ΔT); indeed, ΔT is inversely proportional to cloudiness and therefore could be a good indicator of atmospheric transmittance. As opposed to Rs, daily maximum and minimum air temperatures are measured at many locations and their observations in developed countries b…
Preparation and characterization of dummy-template molecularly imprinted polymers as potential sorbents for the recognition of selected polybrominate…
2018
The main aim of this work was to conduct the preliminary/basic research concerning the preparation process of a new dummy molecularly imprinted polymer (DMIP) materials. Developed DMIPs were proposed as a sorption material in solid-phase extraction (SPE) technique for recognition of selected low mass polybrominated diphenyl ethers (PBDEs) – PBDE-47 and PBDE-99. Four new DMIPs were synthesized employing bulky polymerization technique by application of structural analogue of low mass PBDEs - 4,4′-Dihydroxydiphenyl ether, as a dummy template. The DMIPs and corresponding non-imprinted polymers were prepared using different functional monomers: methacrylic acid; methyl methacrylate and different…
Characterization of ethylene oxide/tert-octylphenol condensates by ultraviolet and infrared spectrometry
1986
Abstract The average degree of condensation of ethylene oxide/tert-octylphenol condensate surfactants can be estimated rapidly by u.v. and i.r. spectrometry. The u.v. method is based on evaluating the specific absorptivity, a , at 275 nm in aqueous ethanol (60:40 v/v), and inserting this value in equations obtained from previously characterized samples, relating a to the average properties to be determined. Infrared spectrometry is applied similarly; the average properties to be determined are related to the ratio between the band heights at 960 and 840 cm −1 . The relative standard deviations ( n = 10) obtained for a sample of Triton X-100 were 2% by u.v. spectrometry, and 3% by i.r. spect…
The use of mathematical models in the characterization of ethylene oxide condensate Surfactants by infrared and ultraviolet spectroscopy
1986
A topological treatment of the surfactant molecules (DARC system) and a group contribution model were applied to study the correlation between structures of ethylene oxide condensates with nonylsphenol and tert-octylphenol and their spectral characteristics such as extinction coefficient of the molecular absortion band. Using the experimental values of the spectral characteristics of an unknown smaple of an ethylene oxide condensate surfactant and the information parameters, previously determined by the mathematical treatment of a key population, it is possible to obtain their average condensation degree.
The role of crystalline, mobile amorphous and rigid amorphous fractions in the performance of recycled poly (ethylene terephthalate) (PET)
2012
[EN] The action of thermo-mechanical degradation induced by mechanical recycling of poly(ethylene terephthalate) was simulated by successive injection moulding cycles. Degradation reactions provoked chain scissions and a reduction in molar mass mainly driven by the reduction of diethyleneglycol to ethylene glycol units in the flexible domain of the PET backbone, and the formation of -OH terminated species with shorter chain length. The consequent microstructural changes were quantified taking into account a three-fraction model involving crystalline, mobile amorphous (MAF) and rigid amorphous fractions (RAF). A remarkable increase of RAF, to a detriment of MAF was observed, while the percen…
Preparation of titanocene and zirconocene dichlorides bearing bulky 1,4-dimethyl-2,3-diphenylcyclopentadienyl ligand and their behavior in polymeriza…
2009
Abstract New metallocene dichlorides [η 5 -(1,4-Me 2 -2,3-Ph 2 -C 5 H) 2 TiCl 2 ] ( 2 ), [η 5 -(1,4-Me 2 -2,3-Ph 2 -C 5 H) 2 ZrCl 2 ] ( 3 ) and [η 5 -(1,4-Me 2 -2,3-Ph 2 -C 5 H)η 5 -(C 5 H 5 )ZrCl 2 ] ( 4 ) were prepared from lithium salt of 1,4-dimethyl-2,3-diphenylcyclopentadiene ( 1 ) and [TiCl 3 (THF) 3 ], [ZrCl 4 ] and [η 5 -(C 5 H 5 )ZrCl 3 (DME)], respectively. Compounds 2–4 were characterized by NMR spectroscopy, EI-MS and IR spectroscopy, and the solid state structure of 3 was determined by single crystal X-ray crystallography. The catalytic systems 3 /MAO and 4 /MAO were almost inactive in polymerization of ethylene at 30–50 °C, however, they exhibited high activity at temperature…