The present paper describes novel low frequency (LF) 1 H NMR energy relaxation time signal analysis for mapping the different chemical and morphological domains in complex cattle manure (CM) and cattle forage (CF) biomass. Relaxation signals generated by different absorbed water pools and aliphatic chains are analyzed by specifically designed sparse representation methods and a convex optimization PDCO solver, for generating 2D T 1 (spin−matrix) vs T 2 (spin−spin) energy relaxation time spectrum graphics and 3D graphs that include 1 H population density. Using analytical spectral analyses and spiking assignment with material standards of the individual T 1 vs T 2 peaks in the generated CM graphics, a morphological and chemical domain dictionary was formulated demonstrating well resolved signal peaks and a better understanding of the different chemical and morphological structural organization within the complex biomass material. This benchtop proton LF-NMR relaxation sensor system and its signal generation into chemical-morphological spectrum graphics has the potential to significantly contribute to a rapid and accurate monitoring system for biobased industrial processes with significant applicability in, for example, biorefineries.

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Magnets, or electromagnets, are common components in everyday appliances and are widely used in medicine, industries, transportation, and electrical power systems. It is known that the magnetic field (B) can mitigate or aggravate metallic corrosion; however, this apparent contradictory effect is still not fully understood. In this study, we demonstrate a simple method to monitor in-operando the effect of permanent magnets (B) on corrosion processes using metallic film (copper clad laminate), FeCl3 solution as corrosive medium, and digital camera to record the experiments. The results show that homogeneous and inhomogeneous B decrease or increase the corrosion rate, respectively. The homogeneous and inhomogeneous B also shows different corrosion patterns and induces rotation of the corrosive medium indicating the presence of the Lorentz force. The procedure proposed can also be applied to other metals and corrosive media providing valuable information on the corrosion process in the presence of B in several environmental conditions.

The corrosion of metals is a major problem of modern societies, demanding new technologies and studies to understand and minimize it. Here we evaluated the effect of a magnetic field (B) on the corrosion of copper in aqueous HCl solution under open circuit potential. The corrosion product, Cu2+, is a paramagnetic ion and its concentration in the solution was determined in real time in the corrosion cell by time-domain NMR relaxometry. The results show that the magnetic field (B = 0.23 T) of the time-domain NMR instrument reduces the corrosion rate by almost 50%, in comparison to when the corrosion reaction is performed in the absence of B. Atomic force microscopy and X-ray diffraction results of the analysis of the corroded surfaces reveal a detectable CuCl phase and an altered morphology when B is present. The protective effect of B was explained by magnetic forces that maintain the Cu2+ in the solution/metal interface for a longer time, hindering the arrival of the new corrosive agents, and leading to the formation of a CuCl phase, which may contribute to the rougher surface. The time-domain NMR method proved to be useful to study the effect of B in the corrosion of other metals or other corrosive liquid media when the reactions produce or consume paramagnetic ions.