scholarly journals Respirometric in Situ Methods for Real-Time Monitoring of Corrosion Rates: Part II. Immersion

2020 ◽  
Author(s):  
Michael Strebl ◽  
Mark Bruns ◽  
Ghina Schulze ◽  
Sannakaisa Virtanen
Keyword(s):  
Real Time ◽  
In Situ Monitoring ◽  
Intermittent Flow ◽  
Real Time Monitoring ◽  
Corrosion Rates ◽  
Immersion Corrosion ◽  
In Situ Methods ◽  
Flow Through ◽  
Corrosion Mechanisms

With the aim to open a new window into corrosion processes this paper presents respirometric methods for real-time in situ monitoring of corrosion rates under immersion conditions. With these techniques, sensitive, non-destructive corrosion rate measurements are possible on basically all metals and alloys. Different methods are presented that enable to monitor HER, ORR or both reactions simultaneously based on the amount of evolved H2 or the amount of consumed O2 by volumetric, manometric and sensor-based approaches. Various research examples are presented, demonstrating the benefits and limitations of the different approaches. For Mg alloys, besides HER, ORR plays a role in the cathodic reactions and a good correlation of the total cathodic charge with mass loss was obtained. H2 dissolution into the electrolyte was identified as an important factor. The results obtained for Zn immersion corrosion in intermittent-flow and flow-through respirometric experiments suggest that the ORR mechanism leads to the generation of stable H2O2 under these conditions. As a result, the effective number of exchanged electrons for one O2 molecule was found to be in between two and four. The here introduced respirometric techniques allow new insights into corrosion mechanisms, in addition to enabling real-time monitoring of corrosion.

scholarly journals Respirometric In Situ Methods for Real-Time Monitoring of Corrosion Rates: Part II. Immersion

2021 ◽  
Vol 168 (1) ◽  
pp. 011502
Author(s):  
M. G. Strebl ◽  
M. P. Bruns ◽  
G. Schulze ◽  
S. Virtanen
Keyword(s):  
Real Time ◽  
Real Time Monitoring ◽  
Corrosion Rates ◽  
In Situ Methods

scholarly journals Respirometric In-Situ Methods for Real-Time Monitoring of Corrosion Rates: Part I. Atmospheric Corrosion

2019 ◽  
Author(s):  
Michael Strebl ◽  
Mark Bruns ◽  
Sannakaisa Virtanen
Keyword(s):  
Mass Loss ◽  
Real Time ◽  
Atmospheric Corrosion ◽  
Cathodic Charge ◽  
High Time Resolution ◽  
Real Time Monitoring ◽  
Field Exposure ◽  
Corrosion Rates ◽  
O2 Reduction

A novel respirometric approach to monitor atmospheric corrosion kinetics is presented. Simultaneous real-time monitoring of the H2 evolution reaction (HER) and the O2 reduction reaction (ORR) is possible with a combination of optical O2 sensor measurements with gravimetric volume sensitive techniques or pressure sensor based techniques in closed chambers. The respirometric method is a universal, non-destructive tool applicable to any metal or alloy. It shows a high sensitivity for low corrosion rates and has a high time-resolution. Different examples of relevant engineering metals and alloys will be provided. Mass loss validation measurements carried out at the end of exposure show a good correlation with the total recorded cathodic charge. For metals with different oxidation states the average valency in the corrosion products can be calculated from the cathodic charge together with mass loss. The versatility of the novel monitoring technique is further demonstrated by studying the influence of wet-dry cycling, temperature steps or changes in the gas composition in-situ. The rate of HER, ORR and total corrosion rate during these changing exposure conditions can be tracked directly on the same sample. Overall the new method contributes to bridging the gap between lab tests, accelerated testing and field exposure.

Novel in-Situ Methods for Real-Time Monitoring of Corrosion

2020 ◽  
Vol MA2020-01 (14) ◽  
pp. 974-974
Author(s):  
Sannakaisa Virtanen
Keyword(s):  
Real Time ◽  
Real Time Monitoring ◽  
In Situ Methods

In-situ techniques for monitoring drinking water quality

2021 ◽  
Author(s):  
Inge Elfferich ◽  
Elizabeth Bagshaw ◽  
Rupert Perkins ◽  
Peter Kille ◽  
Sophie Straiton ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Real Time ◽  
Early Warning ◽  
Drinking Water Quality ◽  
In Situ Monitoring ◽  
Real Time Monitoring ◽  
Early Assessment ◽  
Water Taste

<p>Efficient management of drinking water quality is critical for the water supply, so effective monitoring of supply and storage systems is a priority. This project aims to predict the presence of Taste and Odour (T&O) compounds in drinking water reservoirs, using molecular analyses and smart in-situ monitoring systems. The most common T&O compounds, Geosmin and 2-MIB, are secondary metabolites that can be produced in waterbodies by cyanobacteria and actinomycetes and impact drinking water taste and odour. Although there is no evidence of related health risks, they can be perceived by humans at very low concentrations (5-10 ng/L) and the treatment process to remove them from drinking water is costly. Early assessment of T&O risk is crucial, but currently requires time-consuming and costly sampling as well as laboratory analysis which prevents real-time monitoring and a timely management response.</p><p>Cyanobacterial species responsible for T&O production can be monitored with eDNA techniques and potentially provide an early warning of T&O episodes. Moreover, detection of the genes that are responsible for T&O production within the DNA of the freshwater community can help to speed up analysis. We show that qPCR methods can target the Geosmin synthase gene (geoA) and that this correlates significantly with Geosmin concentrations >15 ng/L. Alternatively, in-situ sensors that can be deployed remotely and transmit data, can provide real-time monitoring for early warning and potentially predictive capacity. Commercially available sensors do not currently exist for T&O compounds, but they do for many other water quality parameters. We consider the analytes that could be effective for T&O warning systems, using a Welsh reservoir as an exemplar case. Assessment of nutrient dynamics suggests N and P ratios are critical, hence we evaluate the sensors that are available for these compounds and associated environmental controls on their behaviour. We present recommendations for the design of an in-situ monitoring programme and introduce the planned tests that will evaluate it.</p>

scholarly journals A sample cell for the study of enzyme-induced carbonate precipitation at the grain-scale and its implications for biocementation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer Zehner ◽  
Anja Røyne ◽  
Pawel Sikorski
Keyword(s):  
Real Time ◽  
Laser Scanning Microscopy ◽  
In Situ Monitoring ◽  
Confocal Laser ◽  
Precipitation Process ◽  
Successful Implementation ◽  
Detailed Knowledge ◽  
Carbonate Precipitation ◽  
Sample Cell

AbstractBiocementation is commonly based on microbial-induced carbonate precipitation (MICP) or enzyme-induced carbonate precipitation (EICP), where biomineralization of $$\text {CaCO}_{3}$$ CaCO 3 in a granular medium is used to produce a sustainable, consolidated porous material. The successful implementation of biocementation in large-scale applications requires detailed knowledge about the micro-scale processes of $$\text {CaCO}_{3}$$ CaCO 3 precipitation and grain consolidation. For this purpose, we present a microscopy sample cell that enables real time and in situ observations of the precipitation of $$\text {CaCO}_{3}$$ CaCO 3 in the presence of sand grains and calcite seeds. In this study, the sample cell is used in combination with confocal laser scanning microscopy (CLSM) which allows the monitoring in situ of local pH during the reaction. The sample cell can be disassembled at the end of the experiment, so that the precipitated crystals can be characterized with Raman microspectroscopy and scanning electron microscopy (SEM) without disturbing the sample. The combination of the real time and in situ monitoring of the precipitation process with the possibility to characterize the precipitated crystals without further sample processing, offers a powerful tool for knowledge-based improvements of biocementation.

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