Search results for "FFC"
showing 9 items of 29 documents
Nuclear Magnetic Resonance with Fast Field-Cycling Setup: A Valid Tool for Soil Quality Investigation
2020
Nuclear magnetic resonance (NMR) techniques are largely employed in several fields. As an example, NMR spectroscopy is used to provide structural and conformational information on pure systems, while affording quantitative evaluation on the number of nuclei in a given chemical environment. When dealing with relaxation, NMR allows understanding of molecular dynamics, i.e., the time evolution of molecular motions. The analysis of relaxation times conducted on complex liquid–liquid and solid–liquid mixtures is directly related to the nature of the interactions among the components of the mixture. In the present review paper, the peculiarities of low resolution fast field-cycling (FFC) NMR rela…
Solid-state 1H-NMR relaxation properties of the fruit of a wild relative of eggplant at different proton Larmor frequencies
2009
1H longitudinal relaxation time profiles (T1) at different proton Larmor frequencies were registered for a solid state plant tissue by using fast field cycling (FFC) nuclear magnetic resonance (NMR) spectroscopy. T1 distributions were obtained and the curves deconvoluted in order to differentiate among the different T1 components. Among the components, two were assigned to hydrophobic (e.g. fatty acids) and hydrophilic (e.g. saccharides) molecular systems, whereas the remaining others were attributed to bulk and bound water. This paper showed for the first time solid state FFC-NMR spectroscopy applied to plant tissue, and revealed that relaxometry is a very promising technique for studying …
Fast field cycling NMR relaxometry characterization of biochars obtained from an industrial thermochemical process
2012
Biochar has unique properties which make it a powerful tool to increase soil fertility and to contribute to the decrease of the amount of atmospheric carbon dioxide through the mechanisms of C sequestration in soils. Chemical and physical biochar characteristics depend upon the technique used for its production and the biomass nature. For this reason, biochar characterization is very important in order to address its use either for agricultural or environmental purposes. Three different biochars obtained from an industrial gasification process were selected in order to establish their chemical and physical peculiarities for a possible use in agronomical practices. They were obtained by char…
Environmental applications of fast field-cycling NMR relaxometry
2019
Environmental sustainability is the modern scientific-field key word. This is because a novel awareness about environmental safety occurred since the “Rio Declaration on Environment and Development” was produced in 1992. For this reason, new and environmentally sustainable analytical techniques have been (and still are) produced. The main focus of these techniques is not only the use of “green” chemicals (i.e. chemical compounds showing low environmental impact), but also the waste reduction through the simplification of the analytical procedures such as extractions and purifications. In particular, the modern analytical trend is to find procedures which allow investigation of complex syste…
DERIVAZIONE DI IDROGRAMMI DI PIENA ATTRAVERSO L’ACCOPPIAMENTO DI MODELLI STOCASTICI BIVARIATI DELLE PRECIPITAZIONI E E MODELLI AFFLUSSI - DEFLUSSI DI…
2012
In questo studio viene presentata una procedura di tipo Monte Carlo per la derivazione delle curve di frequenza delle portate al colmo e dei volumi corrispondenti basata sull’accoppiamento di un modello di generazione delle forzanti pluviometriche tramite copule e un modello di trasformazione afflussideflussi di tipo distribuito. Tale procedura è stata applicata ad un caso di studio siciliano; i risultati ottenuti hanno mostrato la bontà del modello a riprodurre le statistiche complesse delle grandezze idrologiche a fronte di un basso numero di parametri modellistici e di un ridotto sforzo computazionale.
FFC-NMR techniques for assessing the texture features of nanosponges
2021
Nanosponges (NSs), i.e. hyper cross linked polymeric materials obtained by reticulating cyclodextrin units with suitable linker units, constitute an emerging class of functional materials, due to their easy synthesis and chemical modification, and to their tunable absorption and controlled release abilities as well. NSs are supposed to possess a thick network of nanochannels in their highly disordered structure. However, their textural features (average pore size, specific surface and specific pore volume) are quite difficult to estimate, and classical evaluation methodologies (N2 absorption isotherms analyzed by BET or BJH methods, or dye absorption isotherms1) have afforded questionable r…
Sign and rank covariance matrices with applications to multivariate analysis
2002
Differentiation among dairy products by combination of fast field cycling NMR relaxometry data and chemometrics
2021
A set of commercial milk and Sicilian cheeses was analysed by a combination of fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry and chemometrics. The NMR dispersion (NMRD) curves were successfully analysed with a mathematical model applied on Parmigiano-Reggiano (PR) cheese. Regression parameters were led back to the molecular components of cheeses (water trapped in casein micelles, proteins and fats) and milk samples (water belonging to hydration shells around dispersed colloidal particles of different sizes and bulk water). The application of chemometric analysis on relaxometric data enabled differentiating milk from cheeses and revealing differences within the two sa…