Mobile single-sided NMR
The development of NMR instrumentation, methods, and applications of mobile NMR, with particular attention to single-sided NMR is discussed. Inside-out NMR is a form of single-sided or unilateral NMR, where an NMR sensor much smaller than the object is placed near the object to acquire signals from the object volume near the sensor. Mobile NMR holds great promise in a variety of fields, in particular in medicine, materials science, chemical engineering and space science. A very promising area of application of mobile NMR is process control by sensors installed in the production line. The development of NMR methods for mobile NMR is driven by two sources. One is the need for more information from, and better accuracy of, well-logging instruments. The other is scientific curiosity about doing NMR in low and inhomogeneous fields with inexpensive instrumentation and with it the drive for expanding the range of applications of NMR.
Available from: Francesca Benetti
- "The comparison between the Polyptych and the Adorazione dei Magi by Bartolo di Fredi (Andrea's father) that provides a model of the artistic technique used in Sienese painting in the 14th century, allowed to characterize the multilayered structure of the Polyptych. Due to its capability to detect layers containing a different level of hydrogen, portable NMR  was used to obtain the stratigraphy of the painting in situ . Because this technique is fully non-destructive and non-invasive   , a great number of measurements can be carried out in order to get information on the stratigraphy of the whole painting. "
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ABSTRACT: In this study a multi-analytical approach was used to characterize ancient and modern constitutive materials and the stratigraphy of a Sienese wooden painting consisting of four cusps belonging to a lost Polyptych, by Andrea di Bartolo dated back to the late 14th century, repainted in the 16th century and partially restored and cleaned in the 20th century. In order to distinguish the original layers from the other ones, a comparison with the painting Adorazione dei Magi by Bartolo di Fredi (Andrea's father) dated to the 14th century, was performed. The painting Adorazione dei Magi was found to be in a very good state of conservation and provided a model of the artistic technique used in Sienese painting in the 14th century.In situ measurements by portable NMR were performed to investigate the stratigraphy of the paintings in a non-destructive and non-invasive way. By means of this technique, information about all layers constituting the paintings were obtained and used to plan the successive micro-sampling. High resolution NMR spectroscopy was applied on a few samples to characterize binders and organic substances. Specifically, solid state 13C and 31P CPMAS NMR spectroscopy and 1H NMR spectroscopy in solution were applied to characterize original and non-original materials. Other techniques such as ToF-SIMS, HPLC, IR and Raman spectroscopy were also applied.
Available from: Thibaut Colinart
- "In an inhomogeneous magnetic field, such as in NMR MOUSE devices, the NMR signal (FID) decays very quickly and, thus, cannot be directly detected. Therefore, signal decay is generally recovered in single-sided NMR devices by applying Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence . Usually, the first echoes obtained are removed and the decay of the echo amplitudes is fitted using an exponential function. "
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ABSTRACT: Single-sided NMR devices, like NMR MOUSE (MObile Universal Surface Explorer), are designed to allow NMR surface measurements to be conducted on arbitrarily large samples, and are therefore valuable tools to evaluate non-invasively moisture content ‘‘inside’’ a planar object.
In this work, we aim to perform “in situ” studies of moisture transport in building materials during drying experiments with NMR MOUSE. The local moisture content was monitored over time and mapped over sample thickness with a depth resolution of 0.5 mm and a maximum penetration depth of 25 mm. In addition, NMR MOUSE allows measuring longitudinal and transverse relaxation time (T1 and T2) and 2D relaxation spectra, as well as self-diffusion coefficient.
Experimental results show that moisture content is homogeneously distributed over the thickness, which indicates that moisture is transferred through capillary processes. Furthermore, transverse relaxation time distribution measurements revealed that the drainage of pore water occurs sequentially from larger pores to smaller pores.
Available from: Valeria Di Tullio
- "Because the number and the amount of samples collected from precious artifacts must be reduced to a minimum , multi-analytical studies where micro-destructive, non-destructive, and possibly non-invasive techniques are 0935-1221/15/0027-2453 $ 6.30 DOI: 10.1127/ejm/2015/0027-2453 eschweizerbart_xxx combined, are advisable. Within this framework, a breakthrough for the NMR application to cultural heritage has been the development of portable unilateral NMR sensors (Mitchell et al., 2006, 2014; Blümich et al., 2008; Perlo et al., 2011). These instruments, combining open magnets and surface radiofrequecy (RF) coils to generate a sensitive volume external to the sensor and inside the object under investigation, allow one to study non-invasively and in situ variably sized objects (Eidmann et al., 1996). "
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ABSTRACT: Nuclear Magnetic Resonance (NMR) can be successfully applied to a wide number of organic, inorganic, and hybrid materials regarding cultural heritage. High-resolution solid-state NMR provides information on the structure of materials, and portable NMR devices allow non-destructive and non-invasive in situ investigation of variably sized objects. This result is possible by combining open magnets and surface radiofrequency coils to generate a sensitive volume external to the sensor and inside the object under investigation. In this paper we focus on the application of NMR to investigate inorganic porous materials such as pottery, plasters, and stones from cultural heritage sites.
27Al MAS and 3QMAS, and 29Si MAS high-resolution solid-state NMR along with spectral deconvolution allowed for the investigation of the chemical structure of ancient pottery. Portable unilateral NMR was used to investigate, in a non-invasive and non-destructive way, the porous structure of pottery.
The effect of protective-consolidating treatments on plaster was carefully investigated by 1H NMR depth profiles that allowed for scanning with micrometric resolution of plaster specimens. Changes occurring in the total open porosity after treatments were also evaluated.
NMR diffusion measurements provided information on the restricted geometry of the porous structure of two types of biocalcarenite and tuff. A suitable processing of collected data enabled us to define the average pore radius and pores’ interconnection in these materials.
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