Monitoring corrosion-induced thickness loss of stainless steel plates using the electromechanical impedance technique

2020 ◽  
Vol 32 (2) ◽  
pp. 025104 ◽  
Author(s):  
Yang Liu ◽  
Xin Feng
2019 ◽  
Vol 30 (15) ◽  
pp. 2189-2197 ◽  
Author(s):  
Xiujuan Li ◽  
Wenzhong Qu ◽  
Li Xiao ◽  
Ye Lu

Electromechanical impedance technique has been widely used in the area of structural health monitoring. However, both damage and variation in environmental temperature can cause the changes in electromechanical impedance signature, which may cause false damage diagnosis. The temperature effect on the electromechanical impedance-based method has been one of its main drawbacks in practical application. This article proposes a new approach based on cointegration to eliminate temperature interference in the electromechanical impedance technique. The augmented Dickey–Fuller test is used to analyze the stationary characteristics of the time series and determine the degree of non-stationarity. The Johansen test is used to obtain the cointegrating residuals instead of the direct electromechanical impedance responses for damage detection. The proposed method is verified on the undamaged and damaged steel plates with the consideration of environmental temperature variations. The damage detection was based on the electromechanical impedance technique in which the peak frequency is chosen as a cointegrated variable. The experimental results show that the cointegration method can remove the temperature effect on the electromechanical impedance responses, and the cointegrating residuals are effective indices to indicate the occurrence of damage.


2014 ◽  
Vol 121 ◽  
pp. 415-420 ◽  
Author(s):  
Xiuwan Li ◽  
Dan Li ◽  
Zhiwei Wei ◽  
Xiaonan Shang ◽  
Deyan He

Foods ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 103
Author(s):  
Rodrigo Jiménez-Pichardo ◽  
Iriana Hernández-Martínez ◽  
Carlos Regalado-González ◽  
José Santos-Cruz ◽  
Yunny Meas-Vong ◽  
...  

Biofilms on food-contact surfaces can lead to recurrent contamination. This work aimed to study the biofilm formation process on stainless steel plates used in the dairy industry: 304 surface finish 2B and electropolished; and the effect of a cleaning and disinfection process using alkaline (AEW) and neutral (NEW) electrolyzed water. Milk fouling during heat processing can lead to type A or B deposits, which were analyzed for composition, surface energy, thickness, and roughness, while the role of raw milk microbiota on biofilm development was investigated. Bacteria, yeasts, and lactic acid bacteria were detected using EUB-338, PF2, and Str-493 probes, respectively, whereas Lis-637 probe detected Listeria sp. The genetic complexity and diversity of biofilms varied according to biofilm maturation day, as evaluated by 16S rRNA gene sequence, denaturing gradient gel electrophoresis, and fluorescence in situ hybridization microscopy. From analysis of the experimental designs, a cleaning stage of 50 mg/L NaOH of AEW at 30 °C for 10 min, followed by disinfection using 50 mg/L total available chlorine of NEW at 20 °C for 5 min is a sustainable alternative process to prevent biofilm formation. Fluorescence microscopy was used to visualize the effectiveness of this process.


Author(s):  
Irene Carmagnola ◽  
Tiziana Nardo ◽  
Francesca Boccafoschi ◽  
Valeria Chiono

The stainless steel (SS) stents have been used in clinics since 1994. However, typical drawbacks are restenosis and thrombus formation due to limited endothelialisation and hemocompatibility. Surface modification is a smart strategy to enhance antithrombogenicity by promoting endothelialisation. In this work, the layer-by-layer (LbL) technique was applied for coating SS model substrates, after surface priming by functionalisation with 3-aminopropyl triethoxysilane (APTES). A LbL coating made of 14 layers of poly(styrene sulfonate)/poly(diallyldimethylammonium chloride) and heparin as last layer was deposited. FTIR-ATR analysis and contact angle measurements showed that LbL was an effective method to prepare nanostructured coatings. XPS analysis and colorimetric assay employing 1,9-dimethylmethylene blue dye to detect -COOH groups confirmed the successful polyelectrolyte deposition on the coated samples. Preliminary in vitro cell tests, using whole blood and human platelets, were performed to evaluate how surface modification affects platelet activation. Results showed that SS and SS-APTES surfaces induced platelet activation, as indicated by platelet spreading and filopodia formation. After surface modification by LbL coating, the platelets assumed a round shape and no fibrin nets were detected. Data demonstrated that LbL coating is a promising technique to fabricate antithrombogenic surface.


2009 ◽  
Vol 79-82 ◽  
pp. 35-38 ◽  
Author(s):  
Dong Yu Xu ◽  
Xin Cheng ◽  
Shi Feng Huang ◽  
Min Hua Jiang

The structural damage of mortar caused by simulated crack was evaluated using embedded PZT sensor combining with dynamic electromechanical impedance technique. The influence of embedded PZT sensors layout on detecting structural damage induced by the simulated cracks was also investigated. The results indicate that with increasing the simulated crack depth, the impedance real part of PZT sensors shift leftwards accompanying with the appearance of new peaks in the spectra. When more simulated cracks occur, the shift of the impedance curve becomes more obvious, and the amounts of new peaks in the impedance spectra also increase. RMSD indices of the structures with PZT sensors embedded in them with different layout can show the structural incipient damage clearly. With increasing more simulated cracks in the mortar structures, RMSD values of the structures with different PZT sensors layout become larger, under the same depth, RMSD indices of the structures with PZT sensor embedded transversely and horizontally in them show the increasing trend.


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