Flow Nmr
Mostrando 1-12 de 43 artigos, teses e dissertações.
-
1. Alcoholmeter as a Simple and Accessible Way for Ethanol Determination in Alcohol-Based Hand Sanitizers
Expensive and complex methodologies are available to determine the ethanol concentration in alcohol gel samples. The aim of this article was to demonstrate that alcoholmeter could be used as an alternative method to determine ethanol in gel formulations. Alcohol gel samples were produced using: hydroxypropylmethylcellulose (HPMC), hydroxyethylcellulose (HEC)
J. Braz. Chem. Soc.. Publicado em: 2021-06
-
2. Uso da RMN como um sensor online em processos industriais
Nuclear magnetic resonance (NMR) is one of the most versatile analytical techniques for chemical, biochemical and medical applications. Despite this great success, NMR is seldom used as a tool in industrial applications. The first application of NMR in flowing samples was published in 1951. However, only in the last ten years Flow NMR has gained momentum and
Quím. Nova. Publicado em: 2012
-
3. AvaliaÃÃo do desempenho de ligante asfÃltico modificado por poli (Ãcido fosfÃrico) (PPA) e efeitos da adiÃÃo do lÃquido da casca da castanha de caju (LCC). / Performance evaluation of asphalt binder modified poly (phosphoric acid) (PPA) and effects adding the liquid from the bark of cashew (LCC)
The AC with 50/70 penetration grade (Petrobras - LUBNOR), pure and modified by polyphosphoric acid (PPA), was analyzed by rheological tests (viscosity and DSR), thermal analysis (TGA and DSC), spectrometric (NMR and FTIR) and chromatographic (TLC-FID and GPC) methods. The interaction of AC with PPA was investigated from the reactions of its fractions (aromat
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/12/2011
-
4. Analysis of spectral influence of the NMR CWFP parameters in flow quantitative measurements / Análise da influência dos parâmetros espectrais da RMN-CWFP em medidas quantitativas em fluxo
A seqüência de pulsos RMN-CWFP (Ressonância Magnética Nuclear - Precessão Livre de Onda Contínua) tem encontrado diversas aplicações na ciência. O presente trabalho analisa a grande sensibilidade dessa seqüência em relação a variações de seus parâmetros espectrais, exclusivamente em uma caracterização teórico-experimental da RMN-CWFP em fl
Publicado em: 2009
-
5. Síntese e avaliação das atividades fitotóxicas e citotóxicas de compostos análogos aos nostoclídeos
The nostoclides are produced by a cyanobacterium Nostoc sp. symbiont of Peltigera canina, and belong to a family of compounds know as -alkylidenebutenolides. Nostoclides have been shown to have moderate cytotoxicity against the mouse neuroblastoma cell lines Neuro-2a CCL and KB CCL 17. Due to the fact that Peltigera canina cultures are usually not contaminat
Publicado em: 2008
-
6. Study of turbulent flow using Half-Fourier Echo-Planar imaging
The Echo-Planar Imaging technique combined with a partial Fourier acquisition method was used to obtain velocity images for liquid flows in a circular cross-section pipe at Reynolds number of up to 8000. This partial-Fourier imaging scheme is able to generate shorter echo times than the full-Fourier Echo-Planar Imaging methods, reducing the signal attenuatio
Brazilian Journal of Physics. Publicado em: 2006-03
-
7. Magnetic resonance imaging (MRI): a technique to study flow an microstructure of concentrated emulsions
Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) have recently been recognized as important techniques for R&D of products and processes, as is attested by several successful applications in different areas of chemical engineering in recent years. In this article we present new experimental methods based on MRI to study flow and microstr
Brazilian Journal of Chemical Engineering. Publicado em: 2005-03
-
8. Preparação, caracterização e aplicações do material celulose-oxido de zirconio
This work describes the preparation and characterization of the cellulose (Cel) and cellulose acetate (Acel) fibers and cellulose acetate film (Macel) coated with ZrO2. Furthermore, they were modified by reacting phosphoric acid, resulting in the modified materials: Cel/ZrO2/Phosphate and Acel/ZrO2/Phosphate fibers and Macel/ZrO2/Phosphate films. The zirconi
Publicado em: 2003
-
9. Construction of and auto-balanced ac suceptometer and study of eletronic conductor polymers for magnetic susceptibility and magnetic resonance. / Construção de um Susceptômetro AC Autobalanceado e Estudo de Polímeros Condutores Eletrônicos por Susceptibilidade Magnética e Ressonância Magnética.
A mutual inductance bridge which may be used for automatic measurement of ac magnetic susceptibilities from 4 K to room temperature, at frequencies up to 1 kHz, is described. The susceptometer employs an alternative and new arrangement for the probe. The coil set is kept at room temperature and moves in such a way to place the sample in the center of each of
Publicado em: 1998
-
10. Sintese e caracterização de polimeros acrilicos contenco acrilonitrila, acetato de vinila e metilalilsulfonato de sodio
A chemical characterization of acrylic polymers containing acrylonitrile and sodium methallylsulfonate as monomers is presented. The latter monomer introduces ionic groups to the main chain in order to improve polymer tinctorial characteristics. Data obtained are meant to increase the existing information related to the influence of this compound over the ac
Publicado em: 1995
-
11. Quantitative measurement of regional blood flow with gadolinium diethylenetriaminepentaacetate bolus track NMR imaging in cerebral infarcts in rats: validation with the iodo[14C]antipyrine technique.
NMR bolus track measurements were correlated with autoradiographically determined regional cerebral blood flow (rCBF). The NMR method is based on bolus infusion of the contrast agent gadolinium diethylenetriaminepentaacetate and high-speed T*2-sensitive NMR imaging. The first pass of the contrast agent through the image plane causes a transient decrease of t
-
12. Comparative 13C and 31P NMR assessment of altered metabolism during graded reductions in coronary flow in intact rat hearts.
13C NMR spectroscopy may offer a unique ability to characterize the metabolic response to graded reduction in coronary flow since it allows repeated, nondestructive identification of products of intermediary metabolism in the same heart. The sensitivity of 13C parameters of glucose metabolism was compared with changes in levels of phosphocreatine, ATP, and p