Material Loss Rate Research Articles

PMS90 - COST OF WASTAGE IN LOGISTIC MANAGEMENT: THERMOLABILE DRUGS IN THE TREATMENT OF RHEUMATOID ARTHRITIS IN BRAZIL

Most biologic DMARDs (bDMARDs) used in the treatment of rheumatoid arthritis (RA) require special temperature control (2°C – 8°C) in their supply management such as cold chain logistics (CC) to ensure the effectiveness and quality of those products1,2,3. Acknowledging that CC is complex and involves various challenges, this study estimated the wastage costs in the management of temperature sensitive bDMARDs used in the treatment of RA, from the perspectives of the Brazilian health systems (public [SUS] and supplementary [SSS]). An estimative of annual wastage costs in the logistics management of temperature sensitive bDMARDs was performed, using literature data over rates of wastage in CC (1.5%)4 and physical loss of temperature sensitive drugs (2.96%)5, as well as annual data of treatment costs with the bDMARDs etanercept (ETN), adalimumab (ADA), infliximab (INF), abatacept (ABA), golimumab (GOL), certolizumab pegol (CZP) and rituximab (RTX), obtained from SUS and SSS databases, encompassing a sample of 1,000 patients with RA for each one of the listed treatments. Estimates of annual wastage costs in the logistics management of temperature sensitive bDMARDs for SUS and SSS, assuming a wastage rate of 4.5% (managing rate of CC + material loss rate) were: BRL883.615,20 - BRL3.601.276,95 ETN, BRL947.323,62 - BRL3.827.004,69 ADA, BRL753.941,59 - BRL2.474.714,49 INF, BRL735.974,93 - BRL2.608.404,24 ABA, BRL731.821,78 - BRL2.018.972,42 GOL, BRL712.832,88 - BRL1.704.242,71 CZP, BRL507.829,87 - BRL1.043.959,34 RTX, respectively. The analysis suggests that the waste caused by the use of temperature sensitive bDMARDs has a significantly impact in the Brazilian healthcare systems, which could be used to supply an annual treatment of approximately 44 RA patients, regardless the bDMARDs treatment of choice, should be considered other alternatives that not include the CC in the logistic management.

국내 모듈러 주택의 특성 및 MC 설계를 통한 건축자재 표준화 효과 분석

Modular construction is a process in which a building is produced off-site in module boxes using standard materials. Since the introduction of prefabrication in building construction, Modular Coordination (MC) has become an essential design tool in building design and construction. However, in Korea, the design standardization has not been adequately applied to modular construction. This study intends to analyze the current status of modular construction in Korea and explore the applicability of MC design in the construction industry. The analysis of the current status of MC design within Korean four major modular construction companies indicates that an incremental dimension is not properly used in horizontal planning modules, which results in a problem of increasing construction cost by high material loss rate. But, in vertical planning modules, a incremental dimension of 100 mm (1 M) is found to be used although the structural system varies among manufacturers, which demonstrates the potential for an open system to be well applied in modular construction, despite different structural systems.

Wear and Corrosion of Cast Al Alloy Piston with and without Brake Oil

The effects of wear and corrosion of cast AA6061 aluminium alloy were studied with and without brake fluid using a wear jig while the corrosion rate was determined in brake fluid for 70 days under two experimental set-ups. The tests, yielded 0.00000123 g/mm2/min highest wear rate at 147000 wear cycles and 0.0334 mg/mm2/yr as the highest corrosion rate within the early 39th day of immersion in oil, the values being considered comparatively lower than those obtained for Al alloy in most common wet abrasion test and corrosion in aqueous solutions as previously reported in literature. The material loss rates to wear and corrosion were determined from the equations relating to wear and corrosion based on the ASTM designations. The results show that the combined actions of wear and corrosion contribute to the total loss of piston material immersed in brake oil. This is greater than either of their effects individually on cast Al alloy in the brake oil.

Mechanical and Electrochemical Synergism of API X42 Pipeline Steel During Erosion–Corrosion

Hydro-transportation is an economic and flexible way to transport natural resources such as oil and gas from excavation to the extraction plants, refineries, and consumer-ready products to markets. However, interaction between solid particles, corrosive fluid, and target material often results in significant mutual reinforcement due to the combined action of erosion and corrosion. In this study, erosion–corrosion behavior of API pipeline steel has been assessed in 2 g l−1 NaCl solution purged with CO2 as the corrosive media and aluminum oxide as the erodent. Four different particle velocities (36, 47, 63, and 81 m s−1) were employed, while the angle of incidence was kept constant at 90°. The synergism between erosion and corrosion has been studied by means of a newly designed test approach to mitigate the limitations of the in situ method and to identify the effect of erosion on corrosion and vice versa. The corrosion process was monitored using potentiodynamic polarization and weight loss measurements. Total material loss rate and the components of erosion, corrosion, and their synergistic interactions have been determined. Scanning electron microscopy examination and experimental results show that there is an immense correlation between erosion and corrosion. Significant synergism was observed due to the interaction of different erosion and corrosion mechanisms.

Tribological properties of metal matrix composite coatings produced by electrodeposition of copper

Porous templates of graphite and silicon carbide–carbon fibres were fabricated on a copper-110 alloy plate using indirect laser sintering. Copper was deposited electrochemically into the pore network to achieve metal matrix composite coatings using a redox flow battery apparatus. Densities of 89 and 96% were achieved on the copper–graphite composite and copper–SiC composites, respectively. The coefficient of friction and volumetric rate of material loss was determined under a load of 5 N for the coatings and three different sliding speeds of 1200, 1800 and 2400 mm min−1 in sliding wear test. The copper–SiC coatings exhibited a higher wear resistance compared to the copper-110 alloy, while the copper–graphite coatings exhibited a very low coefficient of friction.

Effect of erosion speed on the interaction between erosion and corrosion of the Fe–3.5 wt% B alloy in a flowing zinc bath

Abstract

Investigating the Role of Electrolyte Composition and Oxide Structure in Galvanic Corrosion Susceptibility under Atmospheric Electrolytes

A mechanistic understanding of how electrolyte composition and metal oxide can influence corrosion kinetics in the electrolytes formed from atmospheric processes is investigated. Galvanic couples between aluminum alloys and titanium or stainless steel fasteners exposed to electrolytes formed from atmospheric processes lead to very different corrosion rates. The differences in cathodic current capacity for materials exposed to the same electrolyte at the same aeration level reinforces the fact that oxide microstructure plays a role in catalyzing reduction reactions, though the kinetics of the reaction rates may not be predicted from a simple galvanic series. Also of interest are the changes in reaction rates from acidification of the electrolyte. This suggests that the electrolyte is changing the oxide microstructure or that new reduction reactions are supported and that material loss rates can be orders of magnitude higher for acidified atmospheric electrolytes.

Is there material loss at the backside taper in modular CoCr acetabular liners?

Metal wear and corrosion products generated by hip replacements have been linked to adverse local tissue reactions. Recent investigations of the stem/head taper junction have identified this modular interface as another possible source of metal debris; however, little is known regarding other modular metallic interfaces, their ability to produce metal debris, and possibly to provide insight in the mechanisms that produce metal debris. We asked three questions: (1) can we develop a reliable method to estimate volumetric material loss from the backside taper of modular metal-on-metal liners, (2) do backside tapers of modular metal-on-metal liners show a quantifiable volumetric material loss, and, if so, (3) how do regions of quantitatively identified material loss correspond to visual and microscopic investigations of surface damage? Twenty-one cobalt-chromium (CoCr) liners of one design and manufacturer were collected through an institutional review board-approved retrieval program. All liners were collected during revision surgeries, where the primary revision reason was loosening (n=11). A roundness machine measured 144 axial profiles equally spaced about the circumference of the taper region near the rim to estimate volume and depth of material loss. Sensitivity and repeatability analyses were performed. Additionally, visual and scanning electron microscopy investigations were done for three liners. Our measurement method was found to be reproducible. The sensitivity (how dependent measurement results are on experimental parameters) and repeatability (how consistent results are between measurements) analyses confirmed that component alignment had no apparent effect (weak correlation, R2=0.04) on estimated volumetric material loss calculations. Liners were shown to have a quantifiable material loss (maximum=1.7 mm3). Visual investigations of the liner surface could identify pristine surfaces as as-manufactured regions, but could misidentify discoloration as a possible region of material loss. Scanning electron microscopy more accurately distinguished between as-manufactured and damaged regions of the taper. The roundness machine has been used to develop a repeatable method for characterizing material loss; future work comparing a gravimetric standard with estimations of material loss determined from the roundness machine may show the accuracy and effectiveness of this method. Liners show rates of material loss that compare with those reported for other taper junctions. Visual inspection alone may misidentify as-manufactured regions as regions of material loss. This study identifies the acetabular liner/shell interface in modular metal-on-metal devices as a potential source of metal wear or corrosion products. The relation between metal debris and clinical performance, regardless of the type of bearing couple, is a concern for clinicians. Therefore, it is important to characterize every type of modular junction to understand the quantity, location, and mechanism(s) of material loss.

Quantitative evaluation of 3D surface roughness parameters during cavitation exposure of 16Cr–5Ni hydro turbine steel

The cavitation erosion resistance of 16Cr–5Ni grade martensitic stainless steel was evaluated for long periods of up to 35h in a vibratory cavitation test rig as per the guidelines of the ASTM G32 standard. The change in retained austenite content during the initial period of cavitation was monitored by x-ray diffractometry. The evolution of surface topography features and quantitative 3D surface texture parameters were analyzed after different cavitation exposures. The average surface roughness deviations (Sa), standard deviation roughness (Sq), mean roughness depth (Sz) and surface skewness (Ssk) with cavitation time and the corresponding 2D line roughness parameters Ra, Rq, Rz, and Rsk were evaluated using a confocal laser scanning microscope to identify the damage mechanisms in the steel. Also, the rate of change of the surface area and the cavitated volume during cavitation were studied. Three stages of cavitation erosion, such as incubation, acceleration and steady erosion rate based on metal loss rate were determined. A correlation was observed between the change in roughness profiles during the three stages and their respective rates of material loss. The use of 3D surface parameters is an important tool for monitoring progress of cavitation damage in large-sized components.

Comparison of corrosion behavior of EUROFER and CLAM steels in flowing Pb–15.7Li

Ferritic martensitic steels are envisaged to be applied as structural materials in HCLL blanket systems. Their compatibility with the liquid breeder, which is in direct contact with the structural alloy, will be essential for reliable and safe operation of the designed blankets. Formerly performed corrosion tests of RAFM steels in PICOLO loop of KIT were mainly done at high flow velocities, e.g., 0.22m/s and delivered severe attack with material loss rates above 400μm/yr at 823K. Meanwhile, flow velocities for corrosion testing have been reduced into the “cm range” to be near fusion relevant conditions. Among the international ITER-partners, many varieties of RAFM steels have been developed and manufactured within the last decade, e.g., the so-called Chinese Low Activation Martensitic steel (CLAM).In this paper, the long term corrosion behavior of EUROFER and CLAM steel in flowing Pb–15.7Li will be presented at a flow velocity of about 0.10m/s and compared with earlier obtained results of RAFM steels exposed at other operation parameters of PICOLO loop. The observed corrosion attack is near 220μm/yr and fits well to predictions made by MATLIM-modeling for low flow velocities in the turbulent flow regime.

Investigating the Role of Electrolyte Composition and Oxide Structure in Galvanic Corrosion Susceptibility Under Atmospheric Electrolytes

The goal of this study is to develop a better mechanistic understanding of how electrolyte composition and surface oxides can influence corrosion kinetics in the electrolytes formed from atmospheric processes. It has been observed that galvanic couples between aluminum alloys and titanium or stainless steel fasteners exposed to electrolytes formed from atmospheric processes lead to very different corrosion rates (Z. Feng, G. Frankel, Corrosion, 70(2014) pgs 95-106). In order to collect the data necessary to accomplish this goal, sixteen 2”x2” panels of AA2024, AA7075, CRES 13-8, CRES 17-4, Ti-6Al-4V, and Custom 465 were cut from panel or bar stock and polished to 600 grit SiC. The samples were then mounted in 300 mL Gamry Paracells and exposed for 18 hours to the following electrolytes: 0.6M NaCl at ambient aeration, 6M NaCl at ambient aeration, deoxygenated 0.6M NaCl saturated with nitrogen,0.6M NaCl + 0.01M HCl, 0.6M NaCl + 0.01M H2SO4, and 0.6M NaCl + 0.005M HNO3 + 0.005M H2SO4. The aluminum alloys were then anodically polarized at 0.167 mV/sec from -0.02V below EOC to + 1.5VSCE. The other alloys were polarized cathodically at 0.167 mV/sec from +0.02V above EOC to -1.4VSCE. Results for the cathodic polarization scans of the CRES 13-8PH stainless steel and the Ti-6Al-4V titanium alloy are shown in Figure 1. The differences in cathodic current capacity for materials exposed to the same electrolyte at the same aeration level reinforces the fact that oxide microstructure plays a significant role in catalyzing reduction reactions, though the kinetics of the reaction rates may not be predicted from a simple galvanic series. Of more interest are the changes in reaction rates from acidification of the electrolyte. This suggests that the electrolyte is changing the the oxide microstructure or that new reduction reactions are supported. This is significant because overlays of the anodic polarizations of the aluminum alloys indicate that material loss rates can be orders of magnitude higher for acidified atmospheric electrolytes. These effects are being investigated using microelectrode experiments on droplets of the various electrolytes along with supporting experiments using Scanning Kelvin Probe techniques. Acknowledgements The authors gratefully acknowledge the financial support of the Office of Naval Research Figure 1: Cathodic polarization curves for the titanium alloy Ti-6Al-4V and the stainless steel CRES 13-8PH in 0.6M NaCl and 0.6M NaCl + 0.005M H2SO4 + 0.005M HNO3, showing that materials with different surface oxides and in near-neutral to low-pH electrolytes can support very different cathodic reaction rates with potentially very deleterious consequences for galvanic couples with more active materials.

Diagnostics of cathode material loss in cutting plasma torch

A cutting plasma torch was observed in several ways by a high-speed camera with a focus on the cathode area. In the first experiment, the plasma arc between the nozzle tip and anode was recorded in a series of duty cycles ranging from new unworn cathodes to cathode failure due to wear and material loss. In the second experiment, we used a specially modified nozzle to observe the inside area between the cathode and the nozzle exit through a fused silica window. Finally, using tilted view, we observed a pool of molten hafnium at the cathode tip during the plasma torch operation. The process of cathode material melting, droplet formation, their expulsion and rate of cathode material loss was examined.

The influence of space environment on the evolution of Mercury

Mercury, due to its close location to the Sun, is surrounded by an environment whose conditions may be considered as ‘extreme’ in the entire Solar System. Both solar wind and radiation are stronger with respect to other Solar System bodies, so that their interactions with the planet cause high emission of material from its surface. Moreover, the meteoritic precipitation plays a significant role in surface emission processes. This emitted material is partially lost in space. Although under the present conditions the surface particles loss rate does not seem to be able to produce significant erosion of the planetary mass and volume, the long-term effects over billions of years should be carefully considered to properly understand the evolution of the planet. In the early stages, under even more extreme conditions, some of these processes were much more effective in removing material from the planet’s surface. This study attempts to provide a rough estimation of the material loss rate as a function of time, in order to evaluate whether and how this environmental effect can be applied to understand the Hermean surface evolution. We show that the most potentially effective Sun-induced erosion process in early times is a combination of ion sputtering, photon stimulated desorption and enhanced diffusion, which could have caused the loss of a surface layer down to a depth of 20m, as well as a relevant Na depletion.

A Study on the Construction Waste Forecasting Method Considering Material Loss Rate in South Korea

With the purpose of proposing a construction waste forecasting method specialized for construction phase, this study suggested a forecasting method based on material loss rate to forecase construction wastes with diverse properties. Loss rate of 124 construction materials found in South Korea and Japan was provided. Also to review applicability of construction waste forecasting method using material loss rate, the amount of construction waste found using existing construction waste forecasting method and forecasing method proposed in this study was comparatively analyzed on apartment houses.

Metamaterial band theory: fundamentals & applications

Remarkable progress has been made over the past decade in controlling light propagation and absorption in compact devices using nanophotonic structures and metamaterials. From sensing and modulation, to on-chip communication and light trapping for solar cells, new device applications and opportunities motivate the need for a rigorous understanding of the modal properties of metamaterials over a broad range of frequencies. In this review, we provide an overview of a metamaterial band theory we have developed that rigorously models the behavior of metamaterials made of dispersive materials such as metals. The theory extends traditional photonic band theory for periodic dielectric structures by coupling the mechanical motion of electrons in the metal directly to Maxwell’s equations. The solution for the band structures of metamaterials is then reduced to a standard matrix eigenvalue problem that nevertheless fully takes into account the dispersive properties of the constituent materials. As an application of the metamaterial band theory, we show that one can develop a perturbation formalism based on this theory to physically explain and predict the effect of dielectric refractive index modulation or metallic plasma frequency variation in metamaterials. Furthermore, the metamaterial band theory also provides an intuitive physical picture of the source of modal material loss, as well as a rigorous upper bound on the modal material loss rate of any plasmonic, metamaterial structure. This in turn places fundamental limits on the broadband operation of such devices for applications such as photodetection and absorption.

Erosion–corrosion synergism in an alumina/sea water nanofluid

Since nanofluids increase the thermal conductivity of a fluid mixture compared with the base fluid, it is important to investigate any damaging effects caused by the presence of the solid particles. Thus, this paper explores the nanofluid synergistic effects produced by the addition of 1 g dm−3 Al2O3 nanoparticles to sea water and compares the performance with the base fluid without nanoparticles. Studies are conducted on carbon steel, using a hydrodynamically smooth-rotating cylinder electrode in turbulent flow at 298 K. The pure corrosion rate and erosion rate of carbon steel in the fluids free of nanoparticles are, respectively, higher (up to 82 %) and lower (ca. 11 %) than in the nanofluids. The synergistic effect of erosion and corrosion in a nanofluid is much higher (up to 237 %) than in the base fluid. These results indicate that the presence of nanoparticles in a flowing fluid could lead to considerable rates of material loss.

Exploring new W–B coating materials for the aqueous corrosion–wear protection of austenitic stainless steel

The material loss of metallic surfaces through corrosion–wear is a serious concern in many application sectors, ranging from bio-medical implants to marine, oil and gas field components to transport vehicle and nuclear reactor devices. In principle, self-passivating alloys, like stainless steels, can be protected from surface degradation caused by corrosion–wear through the application of protective thin, hard surface coatings. In this work the suitability of using W matrix coating materials supersaturated with varying levels of boron were applied to austenitic stainless steel substrates (Ortron 90) and assessed for this purpose. These materials were compared to a highly corrosion–wear resistant “datum” surface engineered material (CrN coated Ti–6Al–4V) in sliding contact tests against a chemically inert aluminium oxide ball, whilst immersed in 0.9% NaCl solution at 37°C. The work demonstrated that all the coated materials to be very much more resistant to material loss through corrosion–wear (by nearly an order of magnitude) compared to uncoated stainless steel, and two coatings, W–13%B and W–23%B coated Ortron 90 were similarly resistant as CrN coated Ti–6Al–4V. Three fundamental types of corrosion–wear were discovered that represented differing levels of passive film durability. The total material loss rate (TMLR) during corrosion–wear testing showed linear proportionality with the change in open circuit potential δOCP which obeyed the governing equation: TMLR=m δOCP+C.

Upper Bound on the Modal Material Loss Rate in Plasmonic and Metamaterial Systems

A better understanding of optical loss in plasmonic and metamaterial systems is of increasing importance for both basic and applied research in a broad range of topics including sensors, antennas, optical interconnects, and photovoltaics. In this Letter, we use a photonic band formalism for plasmonics to exactly derive a fundamental upper bound on the nonradiative material loss rate of modes in plasmonic, polaritonic, and metamaterial systems. This bound is purely defined by material properties and cannot be overcome by device design. Moreover it is frequency dependent in the presence of multiple Lorentz poles. We numerically verify this bound through direct calculations for a range of plasmonic systems, including optical antennas where the bound places fundamental performance constraints.

Catastrophic Failure in Cavitation Erosion Testing

AbstractCatastrophic failure of metallic test specimens under cavitation erosion conditions is evidenced by an increasing rate of material loss. The typical cumulative erosion–time curve for this type of failure is denoted as type C. This type of failure depends on the characteristics of the test material, the test method, and the severity of the test conditions. A review of 264 cavitation erosion–time curves, produced via seven test methods, reveals that type C curves are found with 18 % of the specimens and 58 % of the tests performed via the rotating disc test method. This study shows that type C erosion–time curves can be modeled, analyzed, and extrapolated by means of the transient response erosion model. The two main conclusions from this study are that (i) ductile metallic materials are vulnerable to catastrophic erosion failure under severe cavitation erosion conditions, and (ii) the most effective erosion test method for the detection and classification of these materials and conditions is the rotating disc method.

Sliding wear mechanisms of magnesium composites AM60 reinforced with Al2O3 fibres under ultra-mild wear conditions

Mg alloy based composites were fabricated using Al2O3 fibre preforms incorporated in a squeeze cast Mg–6% Al alloy (AM60). AM60–x% (Al2O3)f, where x=9, 11, and 26, samples were subjected to boundary lubricated sliding contact at 25°C and 100°C against AISI 52100 counterface within a load range of 1.0–5.0N. The test parameters emulated ultra-mild wear (UMW) corresponding to wear conditions observed in automotive engine blocks. Wear rates of Mg composites were 104 times less than that of the unreinforced alloy. AM60–9% (Al2O3)f showed the highest rate of material loss compared to AM60–11% (Al2O3)f and AM60–26% (Al2O3)f. In the UMW regime, damage to the composites occurred in the following sequence: (i) fibre fracture and fragmentation; (ii) sinking in of the fragmented fibres; (iii) damage to Mg matrix causing high rate of material loss. Contact stress calculations, based on a micromechanical model that considered the fibres as asperities, indicated that at 1.0N the initial contact pressure (2.8GPa) exceeded the fibre fracture strength in compression. The normal stress on fractured fibres increased as they continued to be fragmented during sliding and became embedded into the matrix causing plastic deformation and localised pile up formation around the fractured fibres. For AM60–26% (Al2O3)f the initial matrix hardness was high due to a large dislocation density created by thermal mismatch during fabrication and led to a greater degree of fragmentation compared to AM60–9% (Al2O3)f revealing that the composite with high Al2O3 fibre volume percentage less wear resistant than expected. FIB and TEM analyses of the worn surfaces of AM60–9% (Al2O3)f tested at 100°C indicated the formation of a tribolayer (oil-residue layer)- that mitigated the damage to Mg matrix tested for high sliding cycles making the AM6O-Al2O3 composites suitable for applications at these temperatures.