Non-destructive Diagnostic Tool Research Articles

A Real Case: How to Combine Polarization Curve and EIS Techniques to Identify Problematic Cells in a Commercial PEM Stack

Nowadays, the mobility sector is assessing different technologies to substitute the internal combustion engines in order to reduce its CO2 emissions; one of these possible alternatives is the Polymer Electrolyte Membrane (PEM) fuel cell. So, the development of non-destructive diagnostic tools that could identify defective cells and/or any malfunctioning behavior and can be easily embarked on in any vehicle will expand the durability of PEM fuel cells, improve their performance, and enable them to carry out predictive maintenance. In this research, we use an in-house developed methodology that combines the polarization curve and electrochemical impedance spectroscopy (EIS) techniques to characterize different cells of a commercial PEM stack, identifying malfunctioning ones.

Receptonics-based real-time monitoring of bacterial volatiles for onsite fire blight diagnosis

Fire blight, caused by the bacterium Erwinia amylovora, is a rapidly progressing and highly contagious disease of apple and pear, which leads to great economic losses with high recovery fees. To control fire blight, the infected trees are either treated with antibiotics or, in some countries, buried. To minimize the damage caused by E. amylovora and to manage its spread to other trees and orchards, early diagnosis of fire blight is critical. The direct extraction of E. amylovora cells or DNA from infected tissues is a laborious and time-consuming process, and a non-destructive diagnosis method has not yet been applied. In this study, we employed receptonics, a nanotechnology platform equipped with a receptor protein that perceives airborne bacterial signals and converts them into electronic signals, for onsite fire blight diagnosis. Two bacterial volatiles, 2,3-butanediol and 2-phenylethyl alcohol, were used as E. amylovora biomarkers both in vitro and in situ. To design receptor protein for identifying the target biomarkers, the bioprobe, nanodiscs human olfactory receptor family 1 subfamily D member 5 (hOR1D5), and Drosophila melanogaster or9a were engineered and fabricated. Our portable receptonics platform was able to detect both bacterial volatiles at concentrations as low as 10 pM within 10 s under field conditions. Thus, our results suggest that the receptonics platform could be used as a non-destructive diagnostic tool for the onsite, rapid, and accurate identification of plant diseases.

Observing the Effect of Architecture on Spiral and Bobbin Lithium Thionyl Chloride (Li/SOCl2) Batteries with Temperature-Dependent Electrochemical Impedance Spectroscopy (EIS)

Electrochemical Impedance Spectroscopy (EIS) has been utilized as an in situ, non-destructive diagnostic tool for the comprehensive electrochemical characterization of lithium thionyl chloride (Li/SOCl2) batteries. Li/SOCl2 batteries come in various geometries or architectures tailored for the application area and required specifications. In this study, detailed EIS studies of spiral and bobbin-type Li/SOCl2 batteries are performed at different temperatures to investigate the impedance response, calculate the activation energy of various processes, and observe the effect of geometry. An extensive comparison between the two geometries reveals that the processes can be differentiated by their time constants and capacitances. It was observed that the current collector impedance masks the high-frequency response of bobbin-type at elevated temperatures with similar Li redox processes in the middle-frequency region. Additionally, transmission line fit is performed on the bobbin type to investigate diffusion-related cathodic processes.

Non-destructive spectroscopic diagnostic tools for the assessment of the mechanical strength of 3D-printed PLA

Polylactic acid (PLA) is a biodegradable and biocompatible thermoplastic that is commonly used in 3D printing. Despite being widely utilized, PLA is susceptible to degradation by both UV light and hydrothermal conditions. This study investigated the effects of 3D printing temperature, UV light exposure, and hydrothermal aging on the properties of PLA. Samples were 3D printed at temperatures of 190, 205, 220 and 235 °C. The specimens were then aged under UV light and thermal cycling or hydrothermally at 80 °C for up to 6 weeks. The aged materials were then characterized using X-ray diffraction (XRD), thermos-gravimetric analysis (TGA), microscopy, mechanical testing, and ultimately Raman spectroscopy.Results showed that the PLA cristallinity increases with aging time in both hydrothermal and under UV exposure conditions, while mechanical strength decreases. Additionally, the UV exposure caused the formation of monomers and oligomers on the outermost layers. Printing temperature was shown to play only a minor role in the determination of the chemophysical properties of the 3D printed components, with faster degradation occurring on samples printed at higher temperatures, which also resulted in higher amounts of monomer when exposed to UV light for 6 weeks.The relative intensities of specific regions of the Raman spectra obtained on the aged samples could be successfully correlated with both the mechanical strength and chemo-physical properties such as the decomposition temperature. The algorithms developed in this study enable non-destructive analysis of PLA components, allowing for the determination of the extent of structural degradation due to environmental aging and the expected residual mechanical resistance.

MODELING AND EXPERIMENTAL INVESTIGATION OF THE EFFECT OF MECHANICAL STRESSES AND DAMAGE OF METAL OF OIL AND GAS EQUIPMENT ON THE PARAMETERS OF ELECTROMAGNETIC-ACOUSTIC CONVERSION

During operation, oil and gas equipment has a wide range of influences, under the influence of which damage accumulates, which transforms into microcracks. Develops the development of microcracks over time can become the destruction of equipment. As established by numerous studies, defects in the structure of the metal originate and develop in the areas of concentration of mechanical inclusions. To prevent the occurrence of emergencies arising from the destruction of equipment, it is necessary to identify zones of increased mechanical detection of diseases and in pathological zones of change control in exceptional cases to detect defects at the very stage of their development. Currently, in the zone of probable concentrations, mechanical quantities are calculated by calculation, and in this case, metal is monitored by non-destructive methods. A very urgent problem in the field of industrial safety of hazardous industries is the creation of detection methods and means for detecting damage to the metal structure in a sharply deformed state. A promising direction for solving this problem is the development of high-performance methods for non-destructive testing of equipment and diagnostics of hazardous production facilities based on the collection of the electromagnetic-acoustic effect (EMA), which make it possible to control the sharply deformed state of equipment and detect metal damage at the structure level. But the current emergence of non-destructive and diagnostic reports based on the EMA effect does not matter for solving problems with sensitivity and informative control. The purpose of this article is to develop an information-measuring complex for studying changes in the acoustic and electrophysical properties of metals in changing their sharply deformed state and damage to the structure. Based on the application of the application of measurement analysis for acoustic and electrophysical studies of the properties of metals and an information-measuring complex. The research results are used to study methods for detecting and processing information intended for EMA parameters, to search for the sensitivity and information content of non-destructive testing and diagnostic tools.

Degradation Diagnosis of Li(Ni0.5Mn0.2Co0.3)O2/Li Half-cell by Identifying Physical Parameter Evolution Profile Using Impedance Spectra During Cycling

Electrochemical Impedance Spectroscopy (EIS) is considered as a quick and nondestructive diagnostic tool to characterize the degradation of LIBs within a short testing timeframe. In this study, to obtain the relationship between EIS spectra and cell capacity degradation, our previously reported physics-based EIS model is further utilized to interpret EIS spectra of Li-NMC(5:2:3) half-cell measured under cycling. The EIS spectra show that the polarization impedance (Rp) increases with the number of cycles under different open circuit voltages (OCVs), especially in the mid-frequency range. After interpreting EIS spectra by the physics-based model, we found that the diffusion coefficient, ionic conductivity, and cathode reaction rate at different OCVs all decrease with the number of cycles. The impedance variation caused by the change of cathode reaction rate during cycles is much more significant than that caused by the other two parameters. Furthermore, the cell capacity degradation is linearly related to the charge transfer resistance (Rct2) caused by cathode/electrolyte interface reaction rate at specific OCVs and it could serve as the indicator of cell capacity fade beyond 10 cycles.

Entropymetry for detecting microcracks in high-nickel layered oxide cathodes

Electric vehicles (EVs) are imposing ever-challenging standards on the lifetime and safety of lithium-ion batteries (LIBs); consequently, real-time nondestructive monitoring of battery cell degradation is highly desired. Unfortunately, high-nickel (Ni) layered oxides, the preferred LIB cathodes for EVs, undergo performance degradation originating from microcrack formation during cycling. Entropymetry is introduced as a real-time analytic tool for monitoring the evolution of microcracks in these cathodes along the state of charge. The entropy change of the layered cathode is associated with the lattice configuration and reflects the structural heterogeneity relevant to the evolution of these microcracks. The structural heterogeneity was correlated with peak broadening in in-situ X-ray diffractometry while varying the experimental conditions that affect crack formation such as the upper cutoff voltage during charging and the Ni-content of the active material. Entropymetry, proposed here as a nondestructive diagnostic tool, can contribute greatly to the safe and reliable operation of LIBs for EVs.

Operando Liquid Water Saturation in PEFC Catalyst Layers Determined Via Small Angle X-Ray Scattering

Various measurement techniques suitable with the length scale of PEFC components have been explored to address the PEFC water management challenge. For the gas diffusion layer (GDL), technological advances have permitted operando water saturation quantification and elucidation of its mechanism with X-ray tomography with few microns resolution 1-4. Furthermore, sub-voxel information contained in the X-ray tomography data has demonstrated accurate water quantification in the nano-porous microporous layer (MPL)5. However, in the nanoscale regime of the catalyst layer, the quantification of water and the mechanism of the water filling the pores remain nontrivial. Studies involving imaging techniques dedicated to understand the water management in the catalyst layer have been carried out albeit with limited spatial resolution6. Nevertheless, the pore-scale information has remained unresolved.Small angle X-ray scattering (SAXS) technique is proposed as a non-destructive diagnostic tool to investigate the catalyst layer saturation in operating conditions. SAXS is well suited for diagnosing the presence of liquid water during operando experiments because of its sensitivity to electron density contrast, nanoscale observation window, high temporal resolution and adequate spatial resolution to distinguish the components in PEFCs. Herein, SAXS intensity profiles measured at cSAXS, Swiss Light Source, Paul Scherrer Institut, Switzerland, with a recently developed SAXS-compatible operando PEFC (Figure 1 middle and right) are interpreted using representative morphology models and assuming different water filling mechanisms (Figure 1 middle and left). The presentation will provide insights into the wetting phenomena in the catalyst layer of PEFC during operation using a representative morphology modelling approach. This work has been presented in XVIII edition of the International Small-Angle Scattering Conference.(1) Xu, H.; Buhrer, M.; Marone, F.; Schmidt, T. J.; Buchi, F. N.; Eller, J. Effects of Gas Diffusion Layer Substrates on PEFC Water Management: Part I. Operando Liquid Water Saturation and Gas Diffusion Properties. J Electrochem Soc 2021, 168 (7).(2) Eller, J.; Rosen, T.; Marone, F.; Stampanoni, M.; Wokaun, A.; Buchi, F. N. Progress in In Situ X-Ray Tomographic Microscopy of Liquid Water in Gas Diffusion Layers of PEFC. J Electrochem Soc 2011, 158 (8), B963-B970.(3) Mularczyk, A.; Lin, Q. Y.; Niblett, D.; Vasile, A.; Blunt, M. J.; Niasar, V.; Marone, F.; Schmidt, T. J.; Buchi, F. N.; Eller, J. Operando Liquid Pressure Determination in Polymer Electrolyte Fuel Cells. Acs Appl Mater Inter 2021, 13 (29), 34003-34011.(4) Sabharwal, M.; Buchi, F. N.; Nagashima, S.; Marone, F.; Eller, J. Investigation of the transient freeze start behavior of polymer electrolyte fuel cells. J Power Sources 2021, 489.(5) Chen, Y. C.; Berger, A.; De Angelis, S.; Schuler, T.; Bozzetti, M.; Eller, J.; Tileli, V.; Schmidt, T. J.; Buchi, F. N. A Method for Spatial Quantification of Water in Microporous Layers of Polymer Electrolyte Fuel Cells by X-ray Tomographic Microscopy. Acs Appl Mater Inter 2021, 13 (14), 16227-16237.(6) Babu, S. K.; Spernjak, D.; Mukundan, R.; Hussey, D. S.; Jacobson, D. L.; Chung, H. T.; Wu, G.; Steinbach, A. J.; Litster, S.; Borup, R. L.; Zelenay, P. Understanding water management in platinum group metal-free electrodes using neutron imaging. J Power Sources 2020, 472. Figure 1

Comparison between Cylindrical, Trigonal, and General Symmetry Models for the Analysis of Polarization-Dependent Second Harmonic Generation Measurements Acquired from Collagen-Rich Equine Pericardium Samples

Polarization-dependent second harmonic generation (PSHG) microscopy is used as an innovative, high-resolution, non-destructive, and label-free diagnostic imaging tool to elucidate biological issues with high significance. In the present study, information on the structure and directionality of collagen fibers in equine pericardium tissue was collected using PSHG imaging measurements. In an effort to acquire precise results, three different mathematical models (cylindrical, trigonal, and general) were applied to the analysis of the recorded PSHG datasets. A factor called the “ratio parameter” was calculated to provide quantitative information. The implementation of the trigonal symmetry model to the recorded data led to the extraction of improved results compared with the application of the widely used cylindrical symmetry model. The best outcome was achieved through the application of the general model that does not include any kind of symmetry for the data processing. Our findings suggest that the trigonal symmetry model is preferable for the analysis of the PSHG datasets acquired from the collagenous tissues compared with the cylindrical model approach although an increased computational time is required.

Raman Spectroscopy Can Distinguish Glyphosate-Susceptible and -Resistant Palmer Amaranth (Amaranthus palmeri).

The non-judicious use of herbicides has led to a widespread evolution of herbicide resistance in various weed species including Palmer amaranth, one of the most aggressive and troublesome weeds in the United States. Early detection of herbicide resistance in weed populations may help growers devise alternative management strategies before resistance spreads throughout the field. In this study, Raman spectroscopy was utilized as a rapid, non-destructive diagnostic tool to distinguish between three different glyphosate-resistant and four -susceptible Palmer amaranth populations. The glyphosate-resistant populations used in this study were 11-, 32-, and 36-fold more resistant compared to the susceptible standard. The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene copy number for these resistant populations ranged from 86 to 116. We found that Raman spectroscopy could be used to differentiate herbicide-treated and non-treated susceptible populations based on changes in the intensity of vibrational bands at 1156, 1186, and 1525 cm–1 that originate from carotenoids. The partial least squares discriminant analysis (PLS-DA) model indicated that within 1 day of glyphosate treatment (D1), the average accuracy of detecting herbicide-treated and non-treated susceptible populations was 90 and 73.3%, respectively. We also found that glyphosate-resistant and -susceptible populations of Palmer amaranth can be easily detected with an accuracy of 84.7 and 71.9%, respectively, as early as D1. There were relative differences in the concentration of carotenoids in plants with different resistance levels, but these changes were not significant. The results of the study illustrate the utility of Raman spectra for evaluation of herbicide resistance and stress response in plants under field conditions.

New insights from Raman MicroSpectroscopy and Scanning Electron Microscopy on the microstructure and chemical composition of vestibular and lingual surfaces in permanent and deciduous human teeth

Teeth are characterized by a specific chemical composition and microstructure, which are related to their nature, permanent and deciduous, and to the sides, lingual and vestibular. Deeper knowledge in this topic could be useful in clinical practice to develop new strategies in restorative dentistry and in the choice of materials with the best performances. In this study, Raman MicroSpectroscopy (RMS), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS), and Vickers MicroHardness (VMH) were exploited to: (1) identify the microstructure and the chemical/elemental composition of permanent and deciduous human teeth, also characterizing their lingual and vestibular sides, and (2) validate a new multidisciplinary analytical approach, for obtaining multiple information on calcified tissues. All applied techniques evidenced differences between permanent and deciduous teeth both in the lingual and vestibular sides. In particular, scanning electron micrographs identified areas with an irregular appearance in the vestibular and lingual sides, which presented also different VMH values. Moreover, RMS and EDS displayed a different chemical/elemental composition in outer and inner enamel and dentin, in terms of Mineral/Matrix, Crystallinity, Carbonates/phosphates, and concentrations by weight (%) of calcium, phosphorous, carbon, magnesium, and sodium. A good linear correlation was found between RMS spectral profiles and EDS and VMH measurements, suggesting that RMS may be considered a useful and non-destructive diagnostic tool for obtaining multiple information on calcified tissues.

Surface-enhanced Raman spectroscopy analysis of serum samples of typhoid patients of different stages

BackgroundSurface-enhanced Raman spectroscopy (SERS) of body fluids is considered a quick, simple and easy to use method for the diagnosis of disease. ObjectivesTo evaluate rapid, reliable, and non-destructive SERS-based diagnostic tool with multivariate data analysis including principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) for classification of different stages of typhoid on the basis of characteristic SERS spectral features. MethodsSERS has been used for analysis of serum samples of different stages of typhoid including early acute stage and late acute stage in comparison with healthy samples, in order to investigate capability of this technique for diagnosis of typhoid. SERS spectral features associated with the biochemical changes taking place during the development of the typhoid fever were analyzed and identified. ResultsThe value of area under the receiver operating characteristics (AUROC) for early acute stage versus healthy is 0.87 and that for healthy versus late acute stage is 0.52. PLS-DA classifier model gives values of 100 % for accuracy, sensitivity and specificity, respectively for the SERS spectral data sets of healthy versus early acute stage. Moreover, this classifier model gives values of 91 %, 89 % and 97 % for accuracy, sensitivity and specificity, respectively for the SERS spectral data sets of healthy versus late acute stage. ConclusionsBased on preliminary work it is concluded that SERS has potential to diagnose various stages of typhoid fever including early acute and late acute stage in comparison with healthy samples.

Diagnosing Stagnant Gas Bubbles in a Polymer Electrolyte Membrane Water Electrolyser Using Acoustic Emission

The use of acoustic emission as a low-cost, non-destructive, and operando diagnostic tool has been demonstrated for a range of electrochemical energy conversion and storage devices, including polymer electrolyte membrane water electrolysers (PEMWEs) and fuel cells. In this work, an abrupt change in acoustic regime is observed during operation of a PEMWE as the current density is increased from 0.5 to 1.0 A cm^{-2}. This regime change is marked by a sudden drop in the number of acoustic hits, while hit duration, amplitude, and energy increase significantly. It is found that the change in acoustic regime coincides with a significant extension of the stagnant bubble region in the flow channels of the PEMWE, observed with high-speed optical imaging. These results demonstrate that acoustic emission can be used effectively as an operando diagnostic tool to monitor bubble formation (two-phase flow conditions) in PEMWEs, facilitating rapid testing or prototyping, and contributing to operational safety.

Acoustic emission as a function of polarisation: Diagnosis of polymer electrolyte fuel cell hydration state

Understanding water management is a crucial aspect in the development of improved polymer electrolyte fuel cells (PEFCs). Separating the performance degradation due to dehydration, water flooding and reactant starvation in PEFCs is a major challenge. In this study, acoustic emission (AE) analysis, a non-invasive and non-destructive diagnostic tool, is utilised to probe water formation and removal inside an operating fuel cell. In the acoustic emission as a function of polarisation (AEfP) method, AE activity from the PEFC is measured in terms of cumulative absolute AE energy (CAEE) hits during operation at discrete points on the polarisation curve. AEfP can identify the presence of liquid water in flow channels and correlate its formation and removal with the level of cell polarisation, and consequent internal temperature. Correlation between acoustic activity and water generation, supply and removal is achieved by varying current (polarisation), cathode air feed relative humidity (RH) and cell temperature, respectively. Features such as initial membrane hydration, liquid water formation, ‘flushing’ and the transition from ‘wet-channel’ to ‘dry-channel’ operation are identified using AE analysis, thereby providing a powerful and easy to implement diagnostic for PEFCs.

Looking Beyond the Surface: Use of High Resolution X-Ray Computed Tomography on Archaeobotanical Remains

High Resolution X-Ray Computed Tomography (HRXCT) offers a powerful 3-dimensional, non-destructive and non-invasive diagnostic tool for imaging the external and internal structures of a range of specimens of interest including archaeobotanical remains. HRXCT offers new possibilities in terms of the research questions which may be asked of fragile and valuable archaeological and specifically archaeobotanical material. This technology, although currently somewhat limited in terms of time and access to beamtimes at National Synchrotrons, requires simple, non-destructive preparation of samples and produces exciting results. Based upon two rounds of successful work we believe that this new methodology has wider implications and utility for advancing the field of imaging, and investigating aspects of plant domestication such as internal anatomical changes.

Coreless SQUID-based cryogenic current comparator for non-destructive intensity diagnostics of charged particle beams

We report on a novel concept and prototype development of a coreless SQUID-based charged-particle beam monitor as a non-destructive diagnostic tool for accelerator facilities. Omitting the typically used pickup coil with a high magnetic permeability core leads to a significant improvement in low-frequency noise performance. Moreover, a revised shielding geometry allows for very compact and rather lightweight device designs. Based on highly sensitive SQUIDs featuring sub-micron cross-type Josephson tunnel junctions, our prototype device exhibits a current sensitivity of about 6 pA Hz−1/2 in the white noise region. Together with a measured shielding factor of about 135 dB this opens up the way for its widespread use in modern accelerator facilities.

Insulation condition assessment of high‐voltage rotating machines using hybrid techniques

The enduring life span of the machine insulation will be decided based on degradation level in motor and generator stator windings. The non-destructive diagnostic tools like dielectric loss and capacitance test and partial discharge (PD) analysis, recognized to access the deterioration in the insulation system of rotating machines. The experiments reveal various characteristic parameters such as leakage current, dielectric dissipation factor, the capacitance value, and PD magnitude. The integrity of the rotating machine can be find out by analyzing these parameters. This research study shows the hybrid method for prediction of insulation condition in the stator winding by utilizing the artificial neural network (ANN) with gravitational search algorithm in comparison with ANN and ANN–genetic algorithm. The advent of expert systems ensures the quality assurance and service life assessment of the high-voltage assets. It offers a predictive maintenance solution to personnel dealt with power utilities thereby increasing the uptime, reliability, and productivity, which in turn reducing the operating costs, downtime and unplanned outages. For testing and predicting the insulation status, several 11 kV machines are considered. The predicted results using hybrid techniques extend a close agreement with reference to the data obtained from the experiments performed. The proposed method indicate the competent and trustworthy, by the presented test results.

Discrimination of malignant and normal kidney tissue with short wave infrared dispersive Raman spectroscopy.

Renal mass biopsy is still controversial due to imperfect accuracy. Raman spectroscopy (RS) demonstrated promise as an in vivo real-time, nondestructive diagnostic tool in many malignancies. Short wave infrared (SWIR) RS has the potential to improve on previous RS systems for renal mass diagnosis. The aim of this study is to evaluate a SWIR RS system in differentiating normal and malignant renal samples. Measurements were acquired using a benchtop RS system with excitation wavelength at 1064 nm and an InGaAs array detector. Processed spectra were classified with a Bayesian machine learning algorithm, sparse multinomial logistic regression. Sensitivity and receiver operating characteristic curve analyses evaluated the classifier accuracy. Accuracy of the classifier was 92.5% with sensitivity and specificity of 95.8% and 88.8%, respectively. For posterior probability of malignant class assignment, the area under the ROC curve is 0.94 (95% confidence interval: 0.89-0.99, P < .001). SWIR RS accurately differentiated normal and malignant kidney tumors. RS has the potential to be used as a diagnostic tool in kidney cancer.

Simple Assessment of Nitrogen Nutrition Index in Summer Maize by Using Chlorophyll Meter Readings.

Rapid and non-destructive diagnostic tools to accurately assess crop nitrogen nutrition index (NNI) are imperative for improving crop nitrogen (N) diagnosis and sustaining crop production. This study was aimed to develop the relationships among NNI, leaf N gradient, chlorophyll meter (CM) readings gradient, and positional differences chlorophyll meter index [PDCMI, the ratio of CM readings between different leaf layers (LLs) of crop canopy] and to validate the accuracy and stability of these relationships across the different LLs, years, sites, and cultivars. Six multi-N rates (0–320 kg ha−1) field experiments were conducted with four summer maize cultivars (Zhengdan958, Denghai605, Xundan20, and Denghai661) at two different sites located in China. Six summer maize plants per plot were harvested at each sampling stage to assess NNI, leaf N concentration and CM readings of different LLs during the vegetative growth period. The results showed that the leaf N gradient, CM readings gradient and PDCMI of different LLs decreased, while the NNI values increased with increasing N supply. The leaf N gradient and CM readings gradient increased gradually from top to bottom of the canopy and CM readings of the bottom LL were more sensitive to changes in plant N concentration. The significantly positive relationship between NNI and CM readings of different LLs (LL1 to LL3) was observed, yet these relationships varied across the years. In contrast, the relationships between NNI and PDCMI of different LLs (LL1 to LL3) were significantly negative. The strongest relationship between PDCMI and NNI which was stable across the cultivars and years was observed for PDCMI1−3 (NNI = −5.74 × PDCMI1−3+1.5, R2 = 0.76**). Additionally, the models developed in this study were validated with the data acquired from two independent experiments to assess their accuracy of prediction. The root mean square error value of 0.1 indicated that the most accurate and robust relationship was observed between PDCMI1–3 and NNI. The projected results would help to develop a simple, non-destructive and reliable approach to accurately assess the crop N status for precisely managing N application during the growth period of summer maize crop.

Toward a non-destructive diagnostic analysis tool of exercises pipelines: models and experiences

Strategic networks of hydrocarbon pipelines, in long time service, are adversely affected by the action of aggressive chemicals transported with the fluids and dissolved in the environment. Material degradation phenomena are amplified in the presence of hydrogen and water, elements that increase the material brittleness and reduce the safety margins. The risk of failure during operation of these infrastructures can be reduced, if not prevented, by the continuous monitoring of the integrity of the pipe surfaces and by the tracking of the relevant bulk properties. A fast and potentially non-destructive diagnostic tool of material degradation, which may be exploited in this context, is based on the instrumented indentation tests that can be performed on metals at different scales. Preliminary validation studies of the significance of this methodology for the assessment of pipeline integrity have been carried out with the aid of interpretation models of the experiments. The main results of this ongoing activity are illustrated in this contribution.