Mass Loss Measurements Research Articles

Meteorite material luminous efficiencies from ground testing of meteoroid entry

The paper reports the determination of luminous efficiency values from ground testing of a comprehensive set of meteorite samples. The ground testing data is translated with commonly used ground to flight extrapolation analogies from atmospheric entry maneuver’s engineering into values of a night observation. This results in a meteor at an altitude of 80km with a flight speed of 11.7km/s of a 34.8 mm diameter spherical meteoroid. A method is developed to determine the total luminous efficiency τ in the bands U, B, V, R, and I from the radiance data and the measured mass loss. For the first time, a measurement of luminous efficiency became possible for known materials. The values itself are in the range of 0.01% to ∼ 1%, which is in the range of previous studies from meteor measurements.

Influence of grain size and crystallographic orientation on microbially influenced corrosion of low-carbon steel in artificial seawater

How the microstructure of steel affects a material’s response to microbially influenced corrosion (MIC) in marine applications remains largely unclear, partly because of the challenge in mapping local structure–property relationships. Focusing on sulphate-reducing bacteria, the onset and rate of MIC on low-carbon marine steel samples were analysed with a wide range of grain size and as a function of the local surface crystallography using a combination of optical and electron microscopy, mass loss measurements, and electrochemical testing. It is shown that the alloy’s resistance to MIC decreases with increasing in grain size. A significant effect of the local crystallographic orientation on the material’s dissolution rate is also recorded, which is lowest along the 〈100〉 crystallographic orientation in this steel when exposed to artificial seawater. These findings outline a clear relationship between the microstructure and the susceptibility to MIC in marine steel, which may be used to design alloys with enhanced resistance to MIC in marine applications.

Synergistic effect between cavitation erosion and corrosion of Monel K500 alloy in 3.5 wt% NaCl solution

Cavitation erosion-corrosion simultaneously damaged the material through mechanical attack and electrochemical corrosion. In this work, experiments were performed on Monel K500 alloy in deionized water and 3.5 wt% NaCl solution using an indirect ultrasonic vibration system to investigate the synergistic effect between cavitation erosion and corrosion. Mass loss measurement and surface topography observation were used to identify the different stages of cavitation erosion. The electrochemical properties at different cavitation stages were analyzed by EIS technique. Results showed that the synergistic effect between cavitation erosion and corrosion exacerbated cavitation damage, and the weight loss rate in 3.5 wt% NaCl solution was about 10% higher than that in deionized water. The increase in ion diffusion and oxygen supply caused by violent agitation accelerated the surface corrosion process, resulting in corrosion-enhanced erosion. Mechanical damage to the material surface during the cavitation process also accelerated the corrosion process, indicating that cavitation-enhanced corrosion was the primary synergistic mechanism. Pure cavitation accounted for 90.75% of total mass loss, suggesting that mechanical deterioration dominated the overall cavitation erosion and corrosion process. Cavitation-enhanced corrosion accounting for 96.12% of the synergistic effect，was the main synergistic mechanism.

ENVIRONMENTAL QUALITY IN EUCALYPTUS SPP. PLANTATIONS DETERMINED FROM FUNCTIONAL PROCESSES OF ITS LITTER

The objective of the study was to understand the influence of Eucalyptus spp. cultivation on the quality of the environment in which it is inserted. For this, three sampling areas of eucalyptus plantations and a control area composed of heterogeneous vegetation. Measurements of leaf litter mass loss, water retention capacity (WRC) tests, and measurements of the content of macronutrients and organic fractions (lignin, cellulose and polyphenols) were carried out in the litter. The litter samples from the control area showed a decomposition coefficient (k) (0.78; 0.82; 0.87) significantly higher than the samples from Eucalyptus spp. (0.51; 0.52; 0.55). For WRC, samples from the control area showed values between 161% and 339%, with an average value of 260%. These were significantly higher than those in the eucalyptus areas, which varied between 72% and 156%, with an average value equal to 112%. As for the content of macronutrients, for the concentration of N, Mg and S in the litter, the samples collected in the control area showed average values significantly higher than the samples from the eucalyptus areas. Regarding the contents of lignin and polyphenols, the samples collected in the eucalyptus areas showed significantly higher values than those presented by the control area. The results obtained showed a strong statistical correlation between the contents of N, Mg, lignin and polyphenols in the sampled leaf material, decomposition rates and water retention capacity. The decomposition of Eucalyptus spp. presented slow decomposition, strongly linked to its chemical composition, which hinders the action of decomposing agents.

The effect of the diode laser beam power on the behaviour of the ZrC powder pre-coat and the 145Cr6 steel substrate during laser processing

The paper presents both the production method and its impact on selected properties of composite coatings reinforced with hard ZrC particles. The Fe/ZrC coatings were produced using diode laser by remelting the pre-coat in the form of paste consisting of ZrC powder and binder. Different values of laser beam power (500 W, 700 W, and 900 W) and different pre-coat thicknesses (100 µm, 150 µm, and 200 µm) were used to produce the composite coatings. During all processes, the scanning speed of laser beam was 3 m/min. Laser beam spot diameter was 1 mm. Microstructure study, microhardness tests, as well as EDS and XRD analysis were carried out. The obtained Fe/ZrC coatings were also tested for the effect of the corrosive medium in a 3.5% NaCl water solution. The effect of applied parameters on wear resistance of Fe/ZrC coatings was also studied. The tribological properties were assessed both by mass loss measurement and by scanning electron microscopy. Fe/ZrC coatings produced using the highest thickness of the pre-coat were characterised by cracks arising during production process. The very high concentration of carbides and hence high hardness of the coating produced in this way contributed to it. However, a positive effect of laser beam power increase on reduction of these cracks was observed. The coatings were characterised by very high hardness, reaching in some cases even more than 2000 HV. It was found that the most favourable properties regarding both tribology and corrosion resistance were obtained for Fe/ZrC coatings produced using 150 µm of pre-coat thickness.

Compatibility of molybdenum with high temperature hydrogen

Arc-cast Molybdenum samples were exposed to a high temperature (2200–2630 K) hydrogen (H2) environment at ∼1 atm to evaluate their chemical compatibility under extreme temperature conditions; this compatibility information is useful to examining the potential application of Mo-matrix cermets for nuclear thermal propulsion applications. Subscale samples were exposed to 1–2 L/min of flowing H2 with hold times of 80 min at temperature (2200–2630 K). The measured mass loss was observed to be slightly lower than that predicted by vapor pressure calculations, which indicates minimal chemical corrosion reactions between Mo and H2 up to temperatures in excess of 90% of the melting temperature of Mo. Grain size dramatically increases across the temperature range. Parallel surface ledges within grains are frequently observed across the sample surface following high temperature hydrogen exposure and in general are related to the orientation of the grain. The observed mass loss is sufficiently low to consider Mo cermets as a candidate fuel for NTP applications.

The role of soybean meal extracts proteins in the inhibition of mild steel acid corrosion

In this research, the mild steel corrosion inhibition effect of three extracts from soybean meal and a soybean protein commercial sample was examined using mass loss tests, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). The anti-corrosive properties of soybean meal extracts were investigated normalizing the peptide/protein amount. The inhibitors were chemically characterized by spectroscopic studies and HPLC. The morphological characterization of the mild steel surface was performed by SEM. Our results demonstrated that all inhibitors showed the same inhibition efficiency if the normalization in peptide/protein amount was performed, indicating proteins/peptides as the class of molecules responsible for inhibiting corrosion. For example, for 100 mg L−1 in protein content, the inhibition efficiency was 84 and 82%, respectively, from electrochemical impedance and polarization curves results, and 89 and 93–94% after 2 and 24 h immersion time, respectively, from mass loss measurements. Polarization curves indicated that all inhibitors behave as a mixed-type inhibitor, more explicit for the cathodic branch. The SEM results suggest that all extracts promoted a protective action against corrosion of the mild steel in H2SO4 solution.

Convective heat transfer correlation for a single surrogate firebrand and a simplified firebrand pile on a flat plate using naphthalene sublimation in heated air flow

Previous studies have shown that most structure ignitions in wildland urban-interface fires are due to firebrand deposition and ignition. The heat transfer mechanisms involved in firebrand deposition need further study and characterization for better understanding of the firebrand ignition process. In particular, convective heat transfer correlations over a single firebrand and a pile of firebrands are lacking. Using the heat-mass transfer analogy, naphthalene sublimation experiments were conducted to determine convective heat transfer correlations for a single naphthalene cylinder (a surrogate firebrand) and an idealized three-firebrand pile resting on flat plates from mass loss measurements. These experiments were conducted in a wind tunnel using a heated (50 °C) or room temperature air flow (0.5 m/s to 2.1 m/s). There was good agreement between the Nusselt number correlation obtained using heated air and results with unheated airflows. Experiments using heated airflow reduced the experimental run times and uncertainty in mass loss measurements significantly. In general, the single firebrand had higher Nusselt numbers than the individual firebrands in the pile. In the three-firebrand pile, the firebrand at the top of the pile exhibited the highest heat transfer. The naphthalene sublimation technique can be easily extended to obtain convective heat transfer correlations for various firebrand geometries and configurations.

Comparison of the Particle Size Distribution and Vapor Phase of Electronic Nicotine Delivery Systems Using Two Impactors

Summary Electronic Nicotine Delivery Systems (ENDS) contain numerous volatile aerosol constituents (e.g., nicotine, propylene glycol, flavors, etc.). Past work clearly indicates the temporal and chemical dynamics of ENDS aerosol requires consideration of these volatile constituents when measuring the particle size distribution. An MSP-135-8 Mini MOUDI™ and Electrical Low Pressure Impactor (ELPI®+) were used to measure the particle size distribution of two JUUL ENDS products. Volatile chemicals were measured from each cascade impactor's exhaust airflow to assess their effect on collection efficiency. Similar mass median aerodynamic diameters were obtained for both ENDS products by both cascade impactors, however the geometric standard deviation from the ELPI®+ measurements were larger for both products than measurements using the Mini MOUDI™ impactor. Although the measured mass of volatile chemicals was greater in the exhaust from the Mini MOUDI™ impactor, a greater variety of volatile chemicals were found within the exhaust of the ELPI®+. The greater variety of volatile chemicals correlated with more room air sampling by the ELPI®+. The reduced amount of volatile chemicals measured in the exhaust of the ELPI®+ may be due to their collection by the vacuum oil used in the sintered collection plates of the ELPI®+. Accounting for the measured volatile chemicals improved the recovery efficiency of the Mini MOUDI™ impactor by 2.9–7.5% with the average recovery efficiency exceeding 82% for the two JUUL ENDS Products. In comparison, accounting for the measured volatile constituents increased the recovery efficiency of the ELPI®+ impactor by 0.4% or less, which did not narrow the recovery efficiency range, that based upon the estimated dilution, consistently exceeded the measured mass loss from both JUUL ENDS products.

Polyvinyl chloride (PVC)/ Halloysite (HNT) nanocomposites: Thermal stability and structural characterization studies

Due to its versatile properties polyvinyl chloride (PVC) based materials are employed in several applications. At high temperatures and in acidic media PVC is prone to release toxic materials into the environment. Several reports are available in the literature about the modification of PVC to minimize such problems. Herein, an attempt is made to prepare PVC/Halloysite nanotube (HNT) nanocomposites with a fixed amount of compatibilizer, OPTIM GE 344 (maleic anhydride modified very low-density polyethylene (VLDPE)) and characterize the composites with respect to thermal stability, mechanical properties, and structural aspects. Both tensile and flexural strength showed appreciable improvement for the 4 wt% loading of the nanofiller. Thermogravimetric analysis (TGA) showed that the maximum degradation temperature improved by approximately 24 °C for 4 wt% filled composites. PVC thermomat measurements of the samples were used to study the thermal stability of the composites. PVC without HNT showed 36 min as the stability time and it increased to 398 min for 4 wt% of HNT loading. To complement the thermal properties of the composites, the mass loss measurement and contact angle behavior of the composite surfaces were also done. The decrease in contact angle values denoted better surface wettability properties. The mass loss measurements showed a decrease with respect to the filler loading of HNT, indicating a better interaction between the polymer matrix and HNT.

The Interstellar Interlopers

Interstellar interlopers are bodies formed outside of the Solar System but observed passing through it. The first two identified interlopers, 1I/‘Oumuamua and 2I/Borisov, exhibited unexpectedly different physical properties. 1I/‘Oumuamua appeared unresolved and asteroid-like, whereas 2I/Borisov was a more comet-like source of both gas and dust. Both objects moved under the action of nongravitational acceleration. These interlopers and their divergent properties provide our only window so far onto an enormous and previously unknown galactic population. The number density of such objects is ∼0.1 AU−3 which, if uniform across the galactic disk, would imply 1025 to 1026 similar objects in the Milky Way. The interlopers likely formed in, and were ejected from, the protoplanetary disks of young stars. However, we currently possess too little data to firmly reject other explanations.▪1I/‘Oumuamua and 2I/Borisov are both gravitationally unbound, subkilometer bodies showing nongravitational acceleration.▪The acceleration of 1I/‘Oumuamua in the absence of measurable mass loss requires either a strained explanation in terms of recoil from sublimating supervolatiles or the action of radiation pressure on a nucleus with an ultralow mass column density, ∼1 kg m−2.▪2I/Borisov is a strong source of CO and H2O, which together account for its activity and nongravitational acceleration.▪The interlopers are most likely planetesimals from the protoplanetary disks of other stars, ejected by gravitational scattering from planets. 1I/‘Oumuamua and 2I/Borisov have dynamical ages ∼108 and ∼109 years, respectively.▪Forthcoming observatories should detect interstellar interlopers every year, which will provide a rapid boost to our knowledge of the population.

Self-healing of recycled aggregate fungi concrete using Fusarium oxysporum and Trichoderma longibrachiatum

This research is aimed to investigate the performance and crack healing phenomenon of recycled aggregate concrete (RAC) by using fungi (Fusarium oxysporum and Trichoderma longibrachiatum) as potential bio-admixtures. The microbial behavior and efficiency of the chosen fungal strains were studied on induction in the RAC by direct intrusion and after being immobilized in recycled coarse aggregate (RCA). The microbial activity in concrete was activated using calcium lactate as nutrition medium. Analysis and comparison of both fungal inoculation approaches with the reference matrix was conducted based on mechanical performance, durability tests, self-healing attributes, and the supporting forensics. Based on the results, F. oxysporum is proven as the potential strain for enhancing RAC performance when immobilized in RCA. The attained increase in compression and tension using F. oxysporum is 11.62 % and 31.18 % respectively at the age of 28 days. Further, the mentioned strain reduced the water absorption by 0.8 % and enhanced the acid resistance of concrete by 4.5 % in terms of measured mass loss. The crack size of 1.34 mm was completely sealed through bio-metabolic activity of F. oxysporum immobilized in RAC and restored 58.75 % of its compressive strength. Fungus hyphae of both the strains were identified in the respective RAC mixes through microscopic examination by Field Emission Scanning Electron Microscopy (FESEM) which proves the compatibility of RCA as the suitable carrier medium for fungi. The crack filler compound was forensically confirmed as bio-calcite through Energy Dispersive X-ray spectroscopy (EDX), Thermogravimetry Analysis (TGA), and X-ray Diffraction (XRD) technique.

Fabrication and characterization of bioprints with Lactobacillus crispatus for vaginal application

Bacterial vaginosis (BV) is characterized by low levels of lactobacilli and overgrowth of potential pathogens in the female genital tract. Current antibiotic treatments often fail to treat BV in a sustained manner, and > 50% of women experience recurrence within 6 months post-treatment. Recently, lactobacilli have shown promise for acting as probiotics by offering health benefits in BV. However, as with other active agents, probiotics often require intensive administration schedules incurring difficult user adherence. Three-dimensional (3D)-bioprinting enables fabrication of well-defined architectures with tunable release of active agents, including live mammalian cells, offering the potential for long-acting probiotic delivery. One promising bioink, gelatin alginate has been previously shown to provide structural stability, host compatibility, viable probiotic incorporation, and cellular nutrient diffusion. This study formulates and characterizes 3D-bioprinted Lactobacillus crispatus-containing gelatin alginate scaffolds for gynecologic applications. Different weight to volume (w/v) ratios of gelatin alginate were bioprinted to determine formulations with highest printing resolution, and different crosslinking reagents were evaluated for effect on scaffold integrity via mass loss and swelling measurements. Post-print viability, sustained-release, and vaginal keratinocyte cytotoxicity assays were conducted. A 10:2 (w/v) gelatin alginate formulation was selected based on line continuity and resolution, while degradation and swelling experiments demonstrated greatest structural stability with dual genipin and calcium crosslinking, showing minimal mass loss and swelling over 28 days. 3D-bioprinted L. crispatus-containing scaffolds demonstrated sustained release and proliferation of live bacteria over 28 days, without impacting viability of vaginal epithelial cells. This study provides in vitro evidence for 3D-bioprinted scaffolds as a novel strategy to sustain probiotic delivery with the ultimate goal of restoring vaginal lactobacilli following microbiological disturbances.

Wear Effect on the Contact between a Metallic Pin and a Rotating Polymeric Specimen

Debris formation is a crucial aspect that determines the lifespan of prosthetic joints. The wearing contact between ultra-high molecular weight polyethylene (UHMWPE) and a Ti alloy surface has been studied in the literature. However, when measuring mass loss, potential errors can arise due to the very small values involved (on the order of some units of 0.1 mg in experiments lasting several hours) and be caused by the absorption of humidity in the specimen, in addition to the lack of accuracy typical of weight scales. These errors can hardly be avoided, but accurate cleaning and drying processes can minimize them. With these premises, the present work aims to determine, by pin-on-disc test, the wear effect in the UHMWPE rotating sheet and Ti6Al4V pin produced by Electron Beam Melting (EBM) under dry and lubricated conditions. The morphology of the worn surface was documented by optical microscopy, and the volume loss of both the rotating specimens and the pin was accurately calculated through the detection of the wear track observed by optical microscopy. In particular, the present work proposes a method for directly determining the volume loss of the polymer to compare it with that obtained with the weight measurement. For both procedures, the uncertainty in evaluating the specific wear rate was analyzed, demonstrating that volume measurement allows for avoiding any possible error associated with weighing the polymeric specimens.

3D Printed Scaffolds Manufactured with Biosilica from Marine Sponges for Bone Healing in a Cranial Defect in Rats.

The inorganic part of marine sponges, called Biosilica (BS), presents an osteogenic potential and the ability of consolidating fractures. Moreover, 3D printing technique is highly effective for manufacturing scaffolds for tissue engineering proposals. Thus, the aims of this study were to characterize the 3D rinted scaffolds, to evaluate the biological effects in vitro and to investigate the in vivo response using an experimental model of cranial defects in rats. The physicochemical characteristics of 3D printed BS scaffolds were analyzed by FTIR, EDS, calcium assay, evaluation of mass loss and pH measurement. For in vitro analysis, the MC3T3-E1 and L929 cells viability was evaluated. For the in vivo evaluation, histopathology, morphometrical and immunohistochemistry analyses were performed in a cranial defect in rats. After the incubation, the 3D printed BS scaffolds presented lower values in pH and mass loss over time. Furthermore, the calcium assay showed an increased Ca uptake. The FTIR analysis indicated the characteristic peaks for materials with silica and the EDS analysis demonstrated the main presence of silica. Moreover, 3D printed BS demonstrated an increase in MC3T3-E1 and L929 cell viability in all periods analyzed. In addition, the histological analysis demonstrated no inflammation in days 15 and 45 post-surgery, and regions of newly formed bone were also observed. The immunohistochemistry analysis demonstrated increased Runx-2 and OPG immunostaining. Those findings support that 3D printed BS scaffolds may improve the process of bone repair in a critical bone defect as a result of stimulation of the newly formed bone.

Fire endurance and corrosion resistance of nano-modified cement mortars exposed to elevated temperatures

In this study, the influence of high temperature on corrosion resistance of steel rebars and the mechanical strength of nano-modified mortars is investigated. Two (2) different mixtures were prepared and tested in the lab; mortars containing 0.2 wt% multi-walled carbon nanotubes (MWCNTs) and mortars without nanomaterials for comparison reasons. The specimens were heated in a furnace up to 800οC for 1 h. Destructive and non-destructive tests were used to evaluate the fire resistance and durability performance of cementitious materials. In particular, the corrosion protection provided by nanomaterials was investigated using electrochemical and mass loss measurements on reinforcing steel, whilst strength tests of mortars were also carried out to evaluate their mechanical behavior after exposure in elevated temperatures. SEM and XRD techniques were used to analyze the surface and microstructure of the steel bars and mortars. The results showed, that the CNT addition slightly improves the strength and durability of mortars exposed to high temperatures as compared with the plain OPC mortar. At the same time, the corrosion resistance of steel rebars was enhanced using carbon nanotubes in mortars after exposure to high temperatures.

Impacts of plant domestication on soil microbial and nematode communities during litter decomposition

PurposePlant domestication altered leaf litter quality. Since litter traits relate to soil functions and organisms (i.e., litter decomposition and soil decomposer communities), in this study we explore if domestication-induced changes in litter quality have affected their decomposability, and bacterial, fungal, and nematode communities in the soil.MethodsWe collected leaf litter from herbaceous crops and their wild progenitors, and measured litter chemical and physical traits. Then, we performed a litter decomposition assay on a common soil. After three months of litter incubation, we measured mass loss, nematode richness and community composition in ten crops. We also measured soil bacterial and fungal richness and community composition in six crops.ResultsDomesticated litters had less carbon (C) and leaf dry matter content (LDMC), which accelerated decomposition in comparison to wild litters. Fungal richness was higher in microcosms incubated with domesticated litters, while the effects of domestication on bacterial richness differed among crops. Domestication did not affect nematode richness. The effects of domestication on bacterial and fungal community compositions differed among crops. Soils with domesticated litters tended to have nematode communities with a higher abundance of bacterial feeding nematodes, in comparison to soils fed with wild litters.ConclusionDomestication altered decomposition at different levels. Leaf litter decomposability increased with domestication, which might alter resource inputs into the soil. Feeding soils with domesticated litters had idiosyncratic effects on soil microbes, but consistent effects on soil nematodes. Overall, domestication altered the linkages between crop residues and soil communities differently for bacteria, fungi, and nematodes.

Thermal decomposition of vegetative fuels and the impact of measured variations on simulations of wildfire spread

This manuscript presents new measurement data from milligram-scale thermal decomposition experiments – thermogravimetric analysis (TGA) and microscale combustion calorimetry (MCC) – conducted on stems and leaves (i.e., needles) of six plant species commonly found across the United States. For each fuel, measurement data from TGA experiments was analyzed to determine effective thermal decomposition mechanisms and the associated kinetics of their constituent reactions. Results of this model calibration were compared to standard (i.e., ‘generalized’) approaches to obtain kinetic parameters available in the literature. MCC experiments were repeated under identical experimental conditions to determine the heats of complete combustion of all gaseous volatiles produced by these vegetative fuels and to validate the decomposition mechanisms and species char yields determined from TGA data. Through a coupled analysis of TGA and MCC measurement data, an estimate of the heats of combustion of the gaseous volatiles produced by individual reaction steps in the fuel’s decomposition was also made. Between different fuels, distinct differences were measured in the onset temperature of decomposition, the temperature range of decomposition, the number of apparent reactions, and the peak measured mass loss and heat release rates (as well as the temperatures at which they occur). To analyze the impact of these variations on predictions of wildfire behavior, a modeling study was then conducted in which simulations of wildland fire experiments were repeated using the thermal decomposition mechanisms and heats of combustion determined for each of the fuel species tested in this work. Model-predicted fire spread rate in these simulations varied between 0.34 m s−1 and 0.80 m s−1 demonstrating a notable dependence (up to a factor of 2x) on measured variations in thermal decomposition mechanism and a second-order dependence on the use of either reaction-step-specific or single (global) heats of combustion.

Microstructure and Cavitation Damage Characteristics of GX40CrNiSi25-20 Cast Stainless Steel by TIG Surface Remelting

Cavitation erosion degrades the surface of engineering components when the material is exposed to turbulent fluid flows. Under conditions of local pressure fluctuations, a nucleation of gas or vapor bubbles occurs. If the pressure suddenly drops below the vapor pressure, these bubbles collapse violently when subjected to higher pressure. This collapse is accompanied by the sudden flow of the liquid, which is manifested by stress pulses capable of causing plastic deformations on solid surfaces. Repeating these stress conditions can cause material removal and ultimately failure of the component itself. The present study aims to reduce the negative impact of this phenomenon on the mechanical systems components, using the TIG local surface remelting technique. Cavitation erosion tests were performed in accordance with the ASTM G32-2016 standard on samples taken from a cast high-alloy stainless steel. The alloy response for each melting current value was investigated by measuring mass loss as a function of cavitation attack time and by analyzing the damaged surfaces using optical and scanning electron microscopes. It was highlighted that the TIG remelted layers provide an increase in cavitation erosion resistance of 5-6 times as a consequence of the fine graining and microstructure induced by the technique applied.

Monitoring and quantification of non-uniform corrosion induced mass loss of steel piles with distributed optical fiber sensors

Steel piles are used in foundation structures to support offshore wind power system, but they suffer from serious non-uniform corrosion in the marine environment, which can threaten the stability and safety of the overall wind tower infrastructure. Thus, real-time and in-situ monitoring of steel pile corrosion is of great significance to provide timely warning and guidance for maintenance. This study deployed a distributed optical fiber sensor beneath the simulated anti-corrosion wrapping system to monitor non-uniform corrosion of steel pile in the four marine corrosion zones: atmospheric zone, water level fluctuation zone, immersion zone, and sub-mud zone. The sensor was applied to measure corrosion products induced strain variation and analyze non-uniform corrosion influenced by different environmental factors. Two analytical models considering build-ups and run-offs of corrosion products were established to quantify non-uniform corrosion induced mass loss at any location on the surface of steel pile. Functions of volume expansion and reduction coefficients of corroded steel pile were proposed, and sensitivity of mass loss measurement with the distributed optical fiber sensor was investigated. Finally, visualization through color cloud map was applied to illustrate the severity of non-uniform corrosion on the pile surface.