scholarly journals Corrosion Sensor Development for Condition-Based Maintenance of Aircraft

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Gino Rinaldi ◽  
Trisha Huber ◽  
Heather McIntosh ◽  
Les Lebrun ◽  
Heping Ding ◽  
...  

Aircraft routinely operate in atmospheric environments that, over time, will impact their structural integrity. Material protection and selection schemes notwithstanding, recurrent exposure to chlorides, pollution, temperature gradients, and moisture provide the necessary electrochemical conditions for the development and profusion of corrosion in aircraft structures. For aircraft operators, this becomes an important safety matter as corrosion found in a given aircraft must be assumed to be present in all of that type of aircraft. This safety protocol and its associated unscheduled maintenance requirement drive up the operational costs of the fleet and limit the availability of the aircraft. Hence, there is an opportunity at present for developing novel sensing technologies and schemes to aid in shifting time-based maintenance schedules towards condition-based maintenance procedures. In this work, part of the ongoing development of a multiparameter integrated corrosion sensor is presented. It consists of carbon nanotube/polyaniline polymer sensors and commercial-off-the-shelf sensors. It is being developed primarily for monitoring environmental and material factors for the purpose of providing a means to more accurately assess the structural integrity of aerospace aluminium alloys through fusion of multiparameter sensor data. Preliminary experimental test results are presented for chloride ion concentration, hydrogen gas evolution, humidity variations, and material degradation.

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1394 ◽  
Author(s):  
Yupeng Tian ◽  
Peng Zhang ◽  
Kaiyue Zhao ◽  
Zhenxing Du ◽  
Tiejun Zhao

An Ag/AgCl electrode used as a corrosion sensor in a reinforced concrete structure is considered as having good application prospect. However, its performance under complex conditions, such as dry-wet cycle condition, is not affirmed. In the current study, the performance of Ag/AgCl as chloride selective electrode in mortar exposed to dry-wet cycle condition was investigated. A simple Ag/AgCl electrode was prepared and fabricated by electrochemical anodization. These Ag/AgCl electrodes were embedded into a mortar specimen with temperature sensors, humidity sensors and anode ladder monitoring system (ALS). After 28 d curing time, the upper surface of mortar specimen was wetted (with 5% NaCl solution) and dried regularly. The obtained results indicate that Ag/AgCl electrode responds to the ingress of chloride ion, sensitively. The chloride ion concentration variation can be reflected by the potential trend. Furthermore, the balance potential of Ag/AgCl electrodes is influenced by dry-wet cycles. Compared with ALS, it demonstrates that Ag/AgCl electrodes are more sensitive to chloride. The research provides the key element for the specific application of Ag/AgCl electrode for corrosion monitoring in the future.


Molecules ◽  
2019 ◽  
Vol 24 (21) ◽  
pp. 3970 ◽  
Author(s):  
Bruna T. L. Pereira ◽  
Mateus A. Gonçalves ◽  
Daiana T. Mancini ◽  
Kamil Kuca ◽  
Teodorico C. Ramalho

Platinum complexes have been studied for cancer treatment for several decades. Furthermore, another important platinum characteristic is related to its chemical shifts, in which some studies have shown that the 195Pt chemical shifts are very sensitive to the environment, coordination sphere, and oxidation state. Based on this relevant feature, Pt complexes can be proposed as potential probes for NMR spectroscopy, as the chemical shifts values will be different in different tissues (healthy and damaged) Therefore, in this paper, the main goal was to investigate the behavior of Pt chemical shifts in the different environments. Calculations were carried out in vacuum, implicit solvent, and inside the active site of P13K enzyme, which is related with breast cancer, using the density functional theory (DFT) method. Moreover, the investigation of platinum complexes with a selective moiety can contribute to early cancer diagnosis. Accordingly, the Pt complexes selected for this study presented a selective moiety, the 2-(4′aminophenyl)benzothiazole derivative. More specifically, two Pt complexes were used herein: One containing chlorine ligands and one containing water in place of chlorine. Some studies have shown that platinum complexes coordinated to chlorine atoms may suffer hydrolyses inside the cell due to the low chloride ion concentration. Thus, the same calculations were performed for both complexes. The results showed that both complexes presented different chemical shift values in the different proposed environments. Therefore, this paper shows that platinum complexes can be a potential probe in biological systems, and they should be studied not only for cancer treatment, but also for diagnosis.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adrian Radoń ◽  
Dariusz Łukowiec ◽  
Patryk Włodarczyk

AbstractThe dielectric properties and electrical conduction mechanism of bismuth oxychloride (BiOCl) plates synthesized using chloramine-T as the chloride ion source were investigated. Thermally-activated structure rebuilding was monitored using broadband dielectric spectroscopy, which showed that the onset temperature of this process was 283 K. This rebuilding was related to the introduction of free chloride ions into [Bi2O2]2+ layers and their growth, which increased the intensity of the (101) diffraction peak. The electrical conductivity and dielectric permittivity were related to the movement of chloride ions between plates (in the low-frequency region), the interplanar motion of Cl− ions at higher frequencies, vibrations of these ions, and charge carrier hopping at frequencies above 10 kHz. The influence of the free chloride ion concentration on the electrical conductivity was also described. Structure rebuilding was associated with a lower concentration of free chloride ions, which significantly decreased the conductivity. According to the analysis, the BiOCl plate conductivity was related to the movement of Cl− ions, not electrons.


2007 ◽  
Vol 40 (s1) ◽  
pp. s213-s216 ◽  
Author(s):  
Yoshiteru Yamada ◽  
Takeo Yajima ◽  
Seiichi Tsukamoto ◽  
Kanako Nakagawa ◽  
Kazuo Fujiwara ◽  
...  

1988 ◽  
Vol 66 (5) ◽  
pp. 637-642 ◽  
Author(s):  
Timothy J. Blaxter ◽  
Peter L. Carlen

The dendrites of granule cells in hippocampal slices responded to γ-aminobutyric acid (GABA) with a depolarization. The response was blocked by picrotoxin in a noncompetitive manner. Reductions in the extracellular chloride ion concentration changed the reversal potential of the response by an amount predicted from the Nernst equation for chloride ion. Chloride-dependent hyperpolarizing responses were sometimes also found in the cell body of the granule cells. Since the reversal potential followed that predicted from the Nernst equation for chloride, we conclude that the response was mediated by chloride ions alone with no contribution from other ions. This has not previously been shown for the depolarizing response to GABA in central neurons.


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