Results 231 to 240 of about 32,501 (269)

Online coupling of thermal field-flow fractionation and Fourier transform infrared spectroscopy as a powerful tool for polymer characterization

Journal of Chromatography A, 2019
The rapid growth and increasing importance of complex polymers has accelerated the need for advancement in characterization techniques. The analysis of such materials is challenging and the determination of different molecular parameters requires the combination of different advanced analytical techniques.
N.W. Radebe, T. Beskers, G. Greyling, H. Pasch   +3 more
openaire   +2 more sources

Fractionation of Asphaltene by Adsorption onto Silica and Chemical Characterization by Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Fourier Transform Infrared Spectroscopy Coupled to Attenuated Total Reflectance, and Proton Nuclear Magnetic Resonance

Energy & Fuels, 2016
Asphaltenes are defined as the petroleum fraction insoluble in n-alkanes and soluble in aromatic solvents, such as toluene. Such definition implies that asphaltenes are not a homogeneous material but a mixture of fractions. Asphaltenes represent one of the major contributors to several problematic issues for the petroleum industry.
Priscila T. H. Nascimento, Alexandre F. Santos, Carlos I. Yamamoto, Lilian V. Tose, Eliane V. Barros, Gustavo R. Gonçalves, Jair C. C. Freitas, Boniek G. Vaz, Wanderson Romão, Agnes P. Scheer   +9 more
openaire   +1 more source

Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Asphaltene Deposit Solubility Fractions: Comparison to Bulk Properties

Energy & Fuels, 2016
In the present work, a field deposit, the solubility fractions, and heptane-precipitated asphaltenes from the crude oil were analyzed using atmospheric pressure photoionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS).
Estrella Rogel, Matthias Witt
openaire   +1 more source

A Unified Framework for 2D Nonseparable Fractional Fourier Transform: From Geometric Completeness to Applications

Signal Processing
The one-dimensional (1D) fractional Fourier transform (FRFT) generalizes the Fourier transform, offering significant advantages in the time-frequency analysis of non-stationary signals.
Daxiang Li, Zhichao Zhang, Wei Yao
semanticscholar   +1 more source

Investigation on nonlinear and fractional derivative Zener model of coupled vehicle-track system

Vehicle System Dynamics, 2020
The nonlinear and fractional derivative Zener model of viscoelastic material considering Berg’s friction force model is established, which can be used to describe the frequency-dependent and amplitude-dependent behaviour of rubber isolator.
Fan Yang, Ping Wang, Kai Wei, Feng Wang
semanticscholar   +1 more source

Sample handling and contamination encountered when coupling offline normal phase high performance liquid chromatography fraction collection of petroleum samples to Fourier transform ion cyclotron resonance mass spectrometry

Analytica Chimica Acta, 2012
Normal phase high performance liquid chromatography (HPLC) is used to separate a gas oil petroleum sample, and the fractions are collected offline and analyzed on a high resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FT-ICR MS).
Nicole E, Oro, Randy M, Whittal, Charles A, Lucy   +2 more
openaire   +2 more sources

Atmospheric Pressure Photoionization and Laser Desorption Ionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Asphaltene Solubility Fractions: Studying the Link between Molecular Composition and Physical Behavior

Energy & Fuels, 2015
In the present work, a series of asphaltene solubility fractions extracted from a heavy crude oil have been analyzed using laser desorption ionization (LDI) and atmospheric pressure photoionization (APPI) coupled to Fourier transform ion cyclotron resonance mass spectrometry.
Estrella Rogel, Michael Moir, Matthias Witt   +2 more
openaire   +1 more source

Mathematical analysis of a time-fractional coupled tumour model using Laplace and finite Fourier transforms

Physica Scripta
Abstract A time-fractional diffusive tumour growth model is investigated in this paper. The model assumes two different tumour populations having diverse diffusion and proliferation rates. The classical integer model, coupled with the fractional operators with power-law, Mittag-Leffler and exponential kernels is solved analytically with ...
Sadia Munir, Andrew Omame, Fiazud Din Zaman   +2 more
openaire   +1 more source

Characterization of Middle-Temperature Gasification Coal Tar. Part 2: Neutral Fraction by Extrography Followed by Gas Chromatography–Mass Spectrometry and Electrospray Ionization Coupled with Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Energy & Fuels, 2012
A commercial lignite gasification-derived middle-temperature coal tar (MTCT) was subjected to acid–base extraction to obtain acidic, basic, and neutral fractions. The neutral fraction was characterized by mass spectrometry (MS) for hydrocarbon-group-type analysis and further fractionated by extrography into six subfractions, which were characterized by
Haiyang Long, Quan Shi, Na Pan, Yahe Zhang, Dechun Cui, Keng H. Chung, Suoqi Zhao, Chunming Xu   +7 more
openaire   +1 more source

Well-posed coupled fractional hyperbolic problem of thermoelasticity

Mathematics and mechanics of solids
This is an attempt to construct the well-posed hyperbolic heat conduction model based on the Caputo fractional derivative and to study the corresponding coupled thermoelastic problem.
S. Sankeshwari, V. Kulkarni
semanticscholar   +1 more source