Metallic Infrastructure Research Articles

Chromium removal from concentrated ammonium-nitrate solution: Electrocoagulation with iron in a plug-flow reactor

Highly concentrated ammonium nitrate (AN) solutions are characteristic of explosives manufacturing wastewaters and liquid fertilizer commodities, but chromium (Cr) contamination from corroding metal infrastructure or source impurities can pose problems. Technologies are needed to decontaminate AN from Cr without chemical alterations if AN is to be recovered as a resource. Iron-based electrocoagulation is a proven way to produce Fe(II) for reducing dissolved Cr(VI) to the less soluble and less toxic form of Cr(III), but is an untested technology for AN brines. This work examined Cr removal from synthetic wastewater with high concentrations of AN (400 g/L) by electrocoagulation in a flow-through reactor, where the effects of time, solution flow rate, applied current, and coexisting ions were analyzed. This method not only reduces Cr(VI) to Cr(III) using the produced Fe(II), but also promotes complete Cr removal from solution with the formation of insoluble Fe-Cr precipitates. A slower flow rate and higher applied current increased the removal efficiency of the reactor; furthermore, the reactor took up to one hour to reach steady state conditions, depending on the flow rate. Cr concentrations along the anode length were modeled using a simplified advection–dispersion-reaction model, providing reaction rate coefficients for various flow rates and currents. Overall, the results of this work showed that electrocoagulation with iron can be used for treatment of AN solution contaminated with Cr(VI). This work also provides design guidelines with a corresponding model for field applications in future work.

Green Corrosion Inhibitors for Metal and Alloys Protection in Contact with Aqueous Saline.

Corrosion is an inevitable and persistent issue that affects various metallic infrastructures, leading to significant economic losses and safety concerns, particularly in areas near or in contact with saline solutions such as seawater. Green corrosion inhibitors are compounds derived from natural sources that are biodegradable in various environments, offering a promising alternative to their conventional counterparts. Despite their potential, green corrosion inhibitors still face several limitations and challenges when exposed to NaCl environments. This comprehensive review delves into these limitations and associated challenges, shedding light on the progress made in addressing these issues and potential future developments as tools in corrosion management. Explicitly the following aspects are covered: (1) attributes of corrosion inhibitors, (2) general corrosion mechanism, (3) mechanism of corrosion inhibition in NaCl, (4) typical electrochemical and surface characterization techniques, (5) theoretical simulations by Density Functional Theory, and (6) corrosion testing standards and general guidelines for corrosion inhibitor selection. This review is expected to advance the knowledge of green corrosion inhibitors and promote further research and applications.

Technological aspects in manufacturing of aesthetic prosthetic restorations with metal infrastructure

Restoring the morphology and functionality of dental arches affected by carious lesions and/or edentations using fixed prosthetic restorations has been a continuous challenge for dentists. Porcelain fused to metal prosthetic restorations using lost wax technique or modern digital methods have proven to be a useful tool in restoring aesthetics and mastication, aspects that lead to the social reintegration of patients. The natural aspect of the prosthetic restoration depends on the talent and inspiration of the dental technician as the art of layering of ceramic masses cannot be surpassed by new emerging technologies.

Directing the photogenerated charge flow in a photocathodic metal protection system with single‐domain ferroelectric PbTiO3 nanoplates

AbstractPhotocathodic protection (PCP) is arguably an ideal alternative technology to the conventional electrochemical cathodic protection methods for corrosion mitigation of metallic infrastructure due to its eco‐friendliness and low‐energy‐consumption, but the construction of highly‐efficient PCP systems still remains challenging, caused primarily by the lack of driving force to guide the charge flow through the whole PCP photoanodes. Here, we tackle this key issue by equipping the PCP photoanode with ferroelectric single‐domain PbTiO3 nanoplates, which can form a directional “macroscopic electric field” throughout the entire photoanode controllable by external polarization. The properly poled PCP photoanode allows the photogenerated electrons and holes to migrate in opposite directions, that is, electrons to the protected metal and holes to the photoanode/electrolyte interface, leading to largely suppressed charge annihilation and consequently a considerable boost in the overall solar energy conversion efficiency of the PCP system. The as‐fabricated photoanode can not only supply sufficient photocurrent to 304 stainless steel to initiate cathodic protection, but also shift the metal potential to the corrosion‐free range. Our findings provide a viable design strategy for future high‐performance PCP systems based on ferroelectric nanomaterials with enhanced charge flow manipulation.

Elucidating microbial iron corrosion mechanisms with a hydrogenase-deficient strain of Desulfovibrio vulgaris.

Sulfate-reducing microorganisms extensively contribute to the corrosion of ferrous metal infrastructure. There is substantial debate over their corrosion mechanisms. We investigated Fe0 corrosion with Desulfovibrio vulgaris, the sulfate reducer most often employed in corrosion studies. Cultures were grown with both lactate and Fe0 as potential electron donors to replicate the common environmental condition in which organic substrates help fuel the growth of corrosive microbes. Fe0 was corroded in cultures of a D. vulgaris hydrogenase-deficient mutant with the 1:1 correspondence between Fe0 loss and H2 accumulation expected for Fe0 oxidation coupled to H+ reduction to H2. This result and the extent of sulfate reduction indicated that D. vulgaris was not capable of direct Fe0-to-microbe electron transfer even though it was provided with a supplementary energy source in the presence of abundant ferrous sulfide. Corrosion in the hydrogenase-deficient mutant cultures was greater than in sterile controls, demonstrating that H2 removal was not necessary for the enhanced corrosion observed in the presence of microbes. The parental H2-consuming strain corroded more Fe0 than the mutant strain, which could be attributed to H2 oxidation coupled to sulfate reduction, producing sulfide that further stimulated Fe0 oxidation. The results suggest that H2 consumption is not necessary for microbially enhanced corrosion, but H2 oxidation can indirectly promote corrosion by increasing sulfide generation from sulfate reduction. The finding that D. vulgaris was incapable of direct electron uptake from Fe0 reaffirms that direct metal-to-microbe electron transfer has yet to be rigorously described in sulfate-reducing microbes.

Ni–Zn bimetal-organic framework nanoprobes reinforced polymeric coating to achieve dual-responsive warning of coating damage and interfacial corrosion

Coating microdefects and localized corrosion in coating/metal system are inevitable, accelerating the degradation of metal infrastructure. Early evaluating coating microdefects and detecting corrosion sites are urgent yet remain challenge to achieve. Herein, we propose a robust, universal and efficient fluorescence-based strategy for hierarchical warning of coating damage and metal corrosion by introducing the concepts of damage-induced fluorescence enhancement effect (DIE) and ionic-recognition induced quenching effect (RIQ). The coatings with dual-responsiveness for coating defect and steel corrosion are constructed by incorporating synthesized nanoprobes composed of metal organic frameworks (Ni–Zn-MOFs) loaded with Rhodamine B (RhB@MOFs). The initial damage to the coating causes an immediate intensification of fluorescence, while the specific ionic-recognition characteristic of RhB with Fe3+ results in an evident fluorescence quenching, enabling the detection of coating damage and corrosion. Importantly, this nanoprobes are insensitive to the coating matrix and exhibit stable corrosion warning capability across various coating systems. Meanwhile, electrochemical investigations indicate that the impedance values of RM/EP maintain above 108 ​Ω ​cm2 even after 60 days of immersion. Therefore, the incorporation of fluorescent nanoprobes greatly inhibits the intrusion of electrolytes into polymer and improves the corrosion protection performance of the coating. This powerful strategy towards dual-level damage warning provides insights for the development of long-term smart protective materials.

Effect of tetrakis(hydroxymethyl)phosphonium sulfate (THPS) on the microbial community and corrosion of carbon steel in a simulated crude-oil storage tank environment

The biocorrosion process has been a problem for the oil and gas industry, involving deterioration of facilities, loss of oil quality, metal loss, and oil leaks. In oil storage tanks, the presence of a metallic surface along with crude oil and water poses a biocorrosion risk. Biocides are used to control the biocorrosion of different metallic infrastructures, tetrakis(hydroxymethyl)phosphonium sulfate (THPS) is commonly used due to its low environmental impact and its effectiveness in preventing sulfate-reducing bacteria (SRB) growth. The treatment effect with one THPS application on microbial community and corrosion rates was evaluated in a batch fractionated assay containing water from a crude oil storage tank, carbon steel coupons and crude oil. The effects of the treatment were monitored for 60 days. The number of planktonic bacteria and archaea estimated by qPCR decreased at the beginning of the treatment with THPS, however, 60 days after the application their number was higher, as were the sulfate-reducing microorganisms (SRM) and methanogens (MA). The diversity analysis of the 16S rRNA gene showed that the relative abundance of the genus Desulfovibrio and Methanocalculus was higher on day 8 in the presence of THPS, but by day 60 there were no differences. The biocide did not inhibit bacterial and archaeal biofilm attached to the SAE 1010 carbon steel coupons and produced a decrease in corrosion rates by blocking the surface. The proximity of the corrosion potential to the pitting potential indicated a high susceptibility to localized corrosion. The results suggested that the changes in the microbial community by THPS treatment were related to the corrosion rates of carbon steel, rather than the number of microorganisms attached to the coupon.

RESnet: 3D direct-current resistivity simulation using the equivalent resistor network circuit

Thin and highly conductive objects are challenging to model in 3D direct-current (DC) problems because they often require excessive mesh refinement that leads to a significant increase in computational costs. RESistor network (RESnet) is a novel algorithm that converts any 3D geo-electric simulation to solving an equivalent 3D resistor network circuit. Two features of RESnet make it an attractive choice in the DC modeling of thin and conductive objects. First, in addition to the conductivity with units of Siemens per meter (S/m) defined at the cell centers (cell conductivity), RESnet allows conductive properties defined on mesh faces and edges as face conductivity with units of S and edge conductivity with units of S·m, respectively. Face conductivity is the thickness-integrated conductivity, which preserves the electric effect of sheet-like conductors without an explicit statement in the mesh. Similarly, edge conductivity is the product of the cross-sectional area and the intrinsic conductivity of a line-like conductive object. Modeling thin objects using face and edge conductivity can avoid extremely small mesh grids if the DC problem concerns electric field responses at a much larger scale. Second, once the original simulation is transformed into an equivalent resistor network, certain types of infrastructure, similar to above-ground metallic pipes, can be conveniently modeled by directly connecting the circuit nodes, which cannot interact with each other in conventional modeling programs. Bilingually implemented in MATLAB and Python, the algorithm has been made open source to promote wide use in academia and industry. Three examples are provided to validate its numerical accuracy, demonstrate its capability in modeling steel well casings, and indicate how it can be used to simulate the effect of complex metallic infrastructure on DC resistivity data.

Mapping soil corrosivity potential to exclusion fencing using pedotransfer functions and open‐source soil data

AbstractSoil corrosivity is a term used to describe the corroding susceptibility (risk) of metal infrastructure in different soil environments. Soil corrosivity mapping is a crucial step in identifying potentially problematic, high‐maintenance fence lines and can help improve fence longevity by identifying soil environments where the use of more expensive, corrosion‐resistant materials would be more cost‐effective in the long term. Soil corrosion damage sustained on exclusion fences can be a serious management issue for conservation programs and initiatives, as it weakens the fence netting and provides opportunities for invasive animal migration and occupation (e.g. feral cats and foxes) into areas of high conservation value. The increasing accessibility of geospatial analysis software and the availability of open‐source soil data provide land managers with the opportunity to implement digital soil databases and pedotransfer functions to produce fence corrosion risk maps using commonly measured soil attributes. This paper uses open‐source government agency soil data (shapefiles) to map fence corrosion risk in the southern part of the Yorke Peninsula in South Australia, with the intention to assist with the installation of a new barrier (exclusion) fence as part of the Marna Banggara rewilding project. The risk classifications (low, moderate and high risk) made by this map were compared with rates of zinc corrosion (μm/year zinc loss) observed at field sites and correctly predicted the amount of fence damage sustained at five of the eight sites. The mapping approach outlined in this study can be implemented by environmental managers in other areas to inform strategies for enhancing fence longevity.

Classic versus digital in the fabrication of the metal infrastructure of fixed prosthetic restoration (Part II)

Classic versus digital in the fabrication of the metal infrastructure of fixed prosthetic restoration (Part II)

Meshing strategies for 3d geo-electromagnetic modeling in the presence of metallic infrastructure

In 3D geo-electromagnetic modeling, an adequate discretisation of the modeling domain is crucial to obtain accurate forward responses and reliable inversion results while reducing the computational cost. This paper investigates the mesh design for subsurface models, including steel-cased wells, which is relevant for many exploration settings but still remains a numerically challenging task. Applying a goal-oriented mesh refinement technique and subsequent calculations with the high-order edge finite element method, simulations of 3D controlled-source electromagnetic models in the presence of metallic infrastructure are performed. Two test models are considered, each needing a distinct version of approximation methods to incorporate the conductive steel casings of the included wells. The influence of mesh quality, goal-oriented meshing, and high-order approximations on problem sizes, computational cost, and accuracy of electromagnetic responses is investigated. The main insights of our work are: (a) the applied numerical schemes can mitigate the computational burden of geo-electromagnetic modeling in the presence of steel artifacts; (b) investigating the processes driving the meshing of models with embedded metallic infrastructures can lead to adequate strategies to deal with the inversion of such electromagnetic data sets. Based on the modeling results and analyses conducted, general recommendations for modeling strategies are proposed when performing simulations for challenging steel infrastructure scenarios.

High performance and cost-effective hybrid steel/CFRP joints using bi-adhesive technique for the repair of metallic infrastructures

The use of the brittle adhesives commonly adopted in construction industry do not provide the best performance for steel structures. CFRP/Steel joint bonded with extremely tough adhesive achieve much higher strength and ductility. However, tough adhesives are not developed for the construction industry and their cost may question the feasibility of this repair solution. This paper presents a new high performance and cost-effective hybrid bi-adhesive CFRP/Steel joint by using an extremely tough adhesive in critical location and the brittle adhesive in the remaining areas of the adhesive layer. The role of the tough adhesive in the proposed joint is fundamentally different from previous bi-adhesive joint proposed in the literature as it contributes mainly in shear. Experimental testing and finite element analysis are conducted. The Digital image correlation (DIC) is used to measure the strain field on the CFRP. The results revealed that the proposed CFRP/Steel hybrid joint achieve higher strength than the joints with brittle adhesive. The use of the tough adhesive in the bi-adhesive joint reduces the concentration of shear stresses significantly. As little quantities of the tough adhesive are required to manufacture the proposed bi-adhesive joint, it deemed to be as cost-effective.

Mapping soil corrosivity in an Australian arid environment and comparing corrosion rates of exclusion fence netting with different zinc coatings

Exclusion fencing and feral-free nature reserves are a key component of many threatened species recovery strategies in Australia. Soil corrosion damage (rust) sustained on exclusion fence netting can create entry points for feral animal incursions into areas of high conservation value. The use of soil physicochemical data to produce corrosivity risk maps is an approach used by project managers to identify the type of corrosion control measures (e.g. use of galvanised zinc coatings) needed to sufficiently limit the deterioration of buried metal infrastructure. This approach is commonly used in subsoil environments (e.g., underground piping), but very few studies have investigated the corrosivity potential of surfaces soils. This paper used surface soil pH, salinity and texture data collected from 69 field sites to map soil corrosivity potential (i.e., fence corrosion risk) at the Arid Recovery nature reserve in South Australia. The majority (72%) of soils in the reserve were predicted to be moderately corrosive and only 16% were predicted to be highly/very highly corrosive. Standard zinc-aluminium fence netting samples buried at six field sites for 18 months were used to validate map predictions. Zinc corrosion on netting samples at field sites were highly variable, particularly at the highly saline (ECe ≥ 5 dS/m) sites. Maximum predicted zinc corrosion rates were within 1.3 μm/year of measured maximum rates at four of the six sites. The fence corrosion risk mapping method used was able to reliably predict areas of low to moderate fence corrosion, but further research is needed to refine its ability to identify high risk areas. An accelerated corrosion experiment (9-month incubation at 65% WHC and elevated ambient temperatures) was used to assess the relative performance of standard zinc-aluminium (124 g/m2 zinc coating), heavy zinc-aluminium (410 g/m2) and heavy galvanised (650 g/m2) fence netting in different soil environments present on the nature reserve. The standard zinc-aluminium wire coating provided sufficient corrosion-resistance for use in the weakly saline (ECe < 5 dS/m) soils (Rhodic Arenosols, Calcic Chromic Solonetz and Chromic Cambisols). However, the increased corrosion-resistance of the heavy zinc-aluminium is needed in the highly saline (ECe ≥ 5 dS/m) Chromic Luvisol. None of the tested fence products were suitable for use in the highly saline Cambic Calcisols. A more corrosive-resistant alternative such as stainless-steel would be more suited for this very highly corrosive environment. Further research is recommended to confirm the long-term (>5 year) suitability of these products in these different soil types.

Statistical Evaluation of the Impacts Detection Methodology (IDM) to Detect Critical Damage Occurrences during Quay Cranes Handling Operations

During various marine container handling operations, performed mainly in larger-scale container terminals, containers get damaged regularly. Our previous studies showed that each physical impact results in some form of physical deformation of the backbone structure. Even at low accelerations, the spreaders of the quay cranes impact the containers with enough force to substantially bend the metal parts of the corners of the containers, when additional hooking procedures are required. This means that the first time resulted in the metal rods hitting the metal frame with an average 15-ton mass at the average speed of 1.7 m/s. The metal rods of the hooking mechanisms’ impact areas of the containers are structurally important, and each impact surely damages the containers, diminishing their total operational time. We have already proposed the Impacts Detection Methodology (IDM) and its application system, tested in Klaipeda City port, and it proved to be efficient in real-time operations, detecting concurrent impacts with each new handling cycle. In this paper, we provide a summarisation of a larger number of detections using the IDM, and as a result of this analysis, we have detected that more impact events happen when containers are taken from the upper parts of the ship, in comparison to the ones taken from the shafts. Results suggest that more critical events occur due to operator actions and experiences working with the machinery, yet the same operators tend to make fewer impact mistakes taking the containers from the shafts as the vertical cell guides tend to direct the movements and lower the levels of the natural sway of the spreader inside closed environments. This surely damages the metal infrastructure of the shafts, as seen in our previous study, but minimizes the chances of secondary impacts occurring during hooking.

Corrosivity of water for concrete and metal water resources infrastructure with modification of the DIN Method and Langelier Saturation Index of Metcalf and Eddy

Corrosion or rust is an endless problem, both in Indonesia and in the world. This is so because corrosion or rust is very detrimental, especially if it occurs in water infrastructure, particularly one built from concrete and metal. Corrosion is a decrease in material quality due to a reaction with the environment. The kinds of losses incurred if corrosion occurs in the infrastructure of water resources include reservoir collapse due to the acceleration of corrosion in the dam, damage to the turbine, and damage to the irrigation gates. This research was conducted to determine level of corrosivity water to water infrastructure built from concrete and metal in 9 (nine) reservoirs. The primary data consist of water quality parameters, determined by sampling the water. The storage and preservation methods of the water samples were done in accordance with Indonesian National Standard Number 6989.57:2008. Water quality was tested by an accredited laboratory. Corrosivity of water for metal and concrete infrastructure was calculated using Metcalf and Eddy formula (2003) and the modification of the DIN 4030 method (2008), respectively. The results of the calculation with Metcalf and Eddy’s LSI (2003) show that the water corrosivity in the 9 (nine) reservoirs had the potential to damage the metal infrastructure, ranging from mild to severe corrosion and lime/crust formation. Based on the modification of the DIN 4030 method (2008), the water in 7 (seven) reservoirs did not have the potential to damage concrete infrastructure, but the water in 2 (two) reservoirs had the potential to damage the concrete infrastructure from mild to moderate level.

Energy in Robotics: An Interdisciplinary Challenge

Energy in Robotics: An Interdisciplinary Challenge

The effect of sambiloto leaf (Andrographis paniculata Nees) extract inhibitor concentration on the corrosion rate of iron in the corrosive HCl medium and well water

Corrosion is a chemical reaction between metal and chemical substances in free air influenced by typographical conditions, climate, and humidity levels around the metal object. If left unchecked, it can cause damage to the metal infrastructure, material losses, and harm in terms of safety and security. Therefore, a way to inhibit corrosion is needed by creating an environmentally friendly inhibitor from natural materials. One of them is by utilizing Sambiloti leaf as a natural inhibitor. Sambiloto leaves contain tannins which can inhibit corrosion well. This study aimed to determine the efficiency of Sambiloto leaves ethanol extract in inhibiting the corrosion rate of metals in the corrosive medium of well water. HCl was soaked for seven days to determine the correlation between the corrosion rate and extract concentration in different corrosive media. Sambiloto leaves were extracted using the soxhletation method using 96% ethanol solution, then distilled to obtain a pure extract. Sambiloto leaf extract was then varied in concentration, namely 1%, 5%, 10%, and 15%. The corrosive medium is well water and HCl, and the metal material used is nails. The results showed that adding Sambiloto extract with a concentration of 15% in both corrosive mediums had the highest inhibitor efficiency values, namely 97.32% in the corrosive HCl medium and 69.3% in the corrosive well water medium. The results of the regression analysis showed that the addition of Sambiloto extract had a significant effect on the corrosion rate in well water media. In contrast, in the HCl medium, the addition of Sambiloto extract did not significantly affect the corrosion rate.

Analysis of the Bacterial Community of Metal Scrap Using an Enrichment Culture Approach

Microbiologically influenced corrosion (MIC) of metal alloys is promoted by biofilms formed on metal surfaces. In the marine environment, MIC causes serious metal infrastructure problems, which lead to significant economic losses. In this study, we used an enrichment culture approach to examine the bacterial community that grows on metal surface at levels below the detection limit as a preliminary study for developing guidelines to prevent biofilm formation. An enrichment culture approach was employed to analyze the bacterial community on metal surface without biofilms and corrosion. Genomic DNA was extracted from culture sample after incubation in the enrichment culture with a metal piece, and then the V3–V4 variable regions of the bacterial 16S rRNA gene were amplified using the extracted genomic DNA as the template. Subsequently, using a next-generation sequencing approach, the amplified V3–V4 regions were sequenced, and the bacterial community was analyzed using the QIIME 2 microbiome bioinformatics platform. Using this enrichment culture approach, more than 80 bacterial genera were detected with Sphingomonas bacteria exhibiting the highest relative abundance (44%). These results demonstrated that this method could be useful for bacterial community analysis for bacteria below detection limits, and will serve as a basis for the development of the guidelines.

Enhancement of MF R-Mode ranging accuracy by exploiting measurement-based error mitigation techniques

Nowadays, the maritime sector strongly relies on global navigation satellite systems (GNSS) for the provision of position, navigation, and timing (PNT) information. The standard functionality of several ships’ bridge instruments depends on such information, which becomes critical to have a safe and reliable navigation. Nevertheless, the possibility of GNSS outages combined with unintentional and intentional interference to GNSS signals, which have been increasing over the last years, can severely threaten the nominal activity of the crew onboard of vessels. For these reasons, alternative position, navigation, and timing (APNT) systems become fundamental in order to provide operational continuity. R(anging)-Mode is a terrestrial alternative system to GNSS for the maritime domain. In one of its possible implementation, it exploits synchronized medium frequency (MF) signals transmitted by maritime radio beacons. In the MF band, the radio waves are attenuated and distorted by the change of electrical properties of the ground along the propagation path. Moreover, these signals are affected by terrain elevation changes and large metallic infrastructures which induce an overall loss in the accuracy of the system. In this paper, we propose a mitigation technique based on the estimation of these additional error sources by using in-field range measurements. The theoretical details are explained in depth and the technique is validated with real data gathered on a measurement campaign. A clear and significant performance improvement is achieved on the range accuracy when the proposed approach is applied.

Sacrificial Anode Cathodic Protection System Modelling Using Direct Boundary Element Method

Abstract Cathodic protection system is commonly employed approach for the protection of the metallic infrastructure placed in electrolyte against corrosion. Adequate design of the cathodic protection system requires the determination of electrical potential and current density distribution on the protected object surface that meets the defined criteria. In this paper, the application of the direct boundary element method in conjunction with Newton-Raphson method was considered for the calculation of the electric potential and current density distribution on the surface of the cathodically protected underground object. The considered method was applied on the sacrificial anode cathodic protection system of the underground pipeline. The non-linear boundary conditions of the electrode surfaces of the cathodic protection system are taken into account. The method was used to determine the current density and electric potential distribution on the external wall of the protected pipeline.