bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of short‐term heat acclimation on whole‐body heat exchange and local nitric oxide synthase‐ and cyclooxygenase‐dependent heat loss responses in exercising older men
Authors: Fujii Naoto , McGarr Gregory W. , Notley Sean R. , Boulay Pierre , Sigal Ronald J. , Amano Tatsuro , Nishiyasu Takeshi , Poirier Martin P. , Kenny Glen P. 
Published: December 2020

New Findings
What is the central question of this study?
Does short‐term heat acclimation enhance whole‐body evaporative heat loss and augment nitric oxide synthase (NOS)‐dependent cutaneous vasodilatation and NOS‐ and cyclooxygenase (COX)‐dependent sweating, in exercising older men?
What is the main finding and its importance?
Our preliminary data (n = 8) demonstrated that short‐term heat acclimation improved whole‐body evaporative heat loss, but it did not influence the effects of NOS and/or COX inhibition on cutaneous vasodilatation or sweating in older men during an exercise–heat stress. These outcomes might imply that although short‐term heat acclimation enhances heat dissipation in older men, it does not modulate NOS‐ and COX‐dependent control of cutaneous vasodilatation or sweating on the forearm.
AbstractAgeing is associated with decrements in whole‐body heat loss (evaporative + dry heat exchange), which might stem from alterations in nitric oxide synthase (NOS)‐ and cyclooxygenase (COX)‐dependent cutaneous vasodilatation and sweating. We evaluated whether short‐term heat acclimation would (i) enhance whole‐body heat loss primarily by increasing evaporative heat loss, and (ii) augment NOS‐dependent cutaneous vasodilatation and NOS‐ and COX‐dependent sweating, in exercising older men. Eight older men [mean (SD) age, 59 (8) years] completed a calorimetry and microdialysis trial before and after 7 days of exercise–heat acclimation. For the calorimetry trials, whole‐body evaporative and dry heat exchange were assessed using direct calorimetry during 30 min bouts of cycling at light, moderate and vigorous metabolic heat productions (150, 200 and 250 W/m2, respectively) in dry heat (40°C, 20% relative humidity). For the microdialysis trials, local cutaneous vascular conductance and sweat rate were assessed during 60 min exercise in the heat (35°C, 20% relative humidity) at four dorsal forearm skin sites treated with lactated Ringer solution (control), NOS inhibitor, COX inhibitor or combined NOS and COX inhibitors, via microdialysis. Evaporative heat loss during moderate (P = 0.036) and vigorous (P = 0.021) exercise increased after acclimation. Inhibition of NOS alone reduced cutaneous vascular conductance to a similar extent before and after acclimation (P < 0.040), whereas separate and combined NOS and COX inhibition had no significant effects on sweating relative to the control site (P = 0.745). Our preliminary results might suggest that short‐term heat acclimation improves evaporative heat loss, but does not significantly modulate the contributions of NOS or COX to cutaneous vasodilatation or sweating on the forearm in older men during an exercise–heat stress.
Investigation of the Localized Corrosion of Ni-Cr-Mo-W Alloy UNS N06022 in Aprotic Solvents at Room Temperature
Authors: Atz Dick Pedro , Kelly Robert 
Published: December 2020

Syntheses of pharmaceuticals often require a series of intermediate steps involving reactions in aprotic organic solvents. Some of these solutions can be aggressive towards the metallic materials that constitute the reaction vessels used, so often corrosion-resistant alloys (CRA) such as the Ni-Cr-Mo-W UNS N06022 are employed. Such materials are expensive, but their use is required to prevent contamination of the product by metal ions. Ni-Cr-Mo-W alloys are known to exhibit outstanding corrosion resistance in reducing and oxidizing aqueous solutions as a result of their passive oxide film. However, the application of passive alloys in nonaqueous solvents raises additional concerns due to: i) limited availability of oxygen atoms for passivation; ii) different behavior of aggressive anions and acids as a result of the solvent’s physicochemical properties. Nevertheless, the literature on corrosion of CRA is focused on behavior in aqueous solutions and the literature on corrosion in organic solvents lacks information on the application of commercial alloys. The aim of this work is to investigate the corrosion of Ni-Cr-Mo-W alloys in aprotic organic solvents and to understand the influence of properties of the solvent on the susceptibility to pitting and to uniform corrosion, at room temperature.
Preliminary work was carried out with anhydrous acetonitrile solutions containing HCl and the oxidant 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Mass loss and electrochemical tests have shown that alloy N06022 exhibits high-rate dissolution in such conditions. The corrosion rates observed after 24 h of immersion are greater than 10 mm/year, which is remarkably high when compared with the existing literature on corrosion of Ni-Cr-Mo alloys. Moreover, in neutral acetonitrile containing chloride, N06022 undergoes pitting at much lower Cl– concentrations and temperature than in aqueous solutions. In order to understand the enhanced susceptibility to pitting and uniform corrosion in aprotic solvents, potentiodynamic polarizations and electrochemical impedance spectroscopy were performed in various solution compositions, followed by surface characterization with scanning electron microscopy. The correlation of passivation and breakdown phenomena with variables of importance, namely water content, chloride concentration, and acidity will be investigated. Ultimately, this study will provide fundamental understanding of the passivity of Ni-based alloys in organic solvents, assisting the selection of materials for nonaqueous applications.
Nanostructure of Anodic Porous Alumina Fabricated By Galvanostatic Anodizing in Etidronic Acid
Authors: Iwai Mana , Kikuchi Tatsuya , Suzuki Ryosuke O. , Natsui Shungo 
Published: December 2020

Galvanostatic and potentiostatic anodizing processes of aluminum leads to the formation of large-scale porous alumina. It is previously reported that self-ordered porous alumina measuring above 500 nm in cell diameter can be fabricated via two-step anodizing in etidronic acid at higher voltage more than 200 V. On the other hand, extremely little has been reported on the growth behavior and their nanostructure during galvanostatic anodizing in etidronic acid. Herein, we investigate the nanostructural characterization of the porous alumina film formed via galvanostatic anodizing in etidronic acid under various operating conditions.
Electropolished aluminum specimens were anodized at a constant current density of 0.005-500 Am-2 in 0.03-3 M etidronic acid solutions at 273-333 K. After anodizing, the porous alumina film was dissolved in a 0.20 M CrO3/0.51 M H3PO4 solution at 353 K, and the aluminum dimple array, which corresponded to the bottom shape of porous alumina, was exposed to the surface. The anodized specimens were examined by field-emission scanning electron microscopy (FE-SEM). The cell size (interpore distance) of the porous alumina was calculated using image analysis software.
Typical voltage-time curves for the formation of anodic porous alumina were obtained during galvanostatic anodizing in etidronic acid: The voltage linearly increased, gradually decreased, and then reached plateau value. However, excess current density caused oxide burning with unstable oscillation in the voltage-time curve, and non-uniform porous alumina was formed on the aluminum surface. The plateau voltage greatly increased with the current density at each operating temperature, and various porous alumina films with different nanostructures were successfully fabricated by anodizing at a wide voltage range measuring 7-218 V. Figure 1 shows the changes in the average, maximum, and minimum cell sizes with the anodizing voltage under various operating conditions. The cell sizes are directly proportional to the anodizing voltage with proportionality constants of 2.5 (average), 3.5 (maximum), and 0.7 (minimum), respectively.

Figure 1
(Invited) Characterization of Cathodic Properties of Anodized Titanium By a Fast Current-Controlled Polarization
Authors: Fujimoto Shinji , Kurokawa Tetsuya , Tsuchiya Hiroaki , Miyabe Sayaka 
Published: December 2020

Oxygen reduction is one of the most important reactions in corrosion process. Therefore, oxygen reduction has been extensively studied on metals and alloys, the surface of which is covered with oxide film. In general, the oxygen reduction reaction during localized corrosion is considered to occur extremely fast, but such rapid cathodic process has not been reported. In the present work, we propose an approach to investigate rapid oxygen reduction reaction, A Fast Current-Controlled Polarization, where a fast cathodic current transient is applied to metals and alloys covered with oxide film and from the resulting potential variation, the kinetics of the oxygen reduction on the surface is analyzed.
In this presentation the results on Ti will be delivered. Oxide films on Ti were produced by anodization in a phosphate buffer solution at various voltages ranging from 3 V to 50 V, resulting in different thickness and crystallinity. On the basis of the potential variation and the potential dependence of the capacitance, the oxygen reduction current-time profile during the fast current-controlled polarization was estimated and as a result the quasi-polarization curve of the oxygen reduction reaction was obtained. The quasi-polarization curves obtained for the anodized substrates were categorized into two type; the linear slope and the wide loop. These differences were attributed to the crystallinity of the oxide film on titanium. Considering the correlation between the crystallinity of anodic film and its conductivity, these results imply that the fast oxygen reduction on passivated metals will be affected by the crystallinity and resulting conductivity of oxide film. In this study, details on the fast current controlled polarization on Zr, Al and others was also presented and the different reduction kinetics will be discussed in this presentation.
(Invited) Cryo-Based FIB/SEM Characterization of Salt Film on Metal
Authors: Li Tianshu , Perea Daniel , Schreiber Daniel , Wirth Mark , Orren Graham , Frankel Gerald S. 
Published: December 2020

Metal salt films play a critical role in high rate dissolution processes such as within an active pit.1-5 To better understand the film growth mechanism, the salt film structure and composition must be characterized with high resolution, which however, is challenging owing to the dynamic nature of the dissolving interface. In this work, a novel cryogenic specimen preparation approach to preserve the pit solution and salt film was introduced, allowing ex situ characterization of the native structure formed on the dissolving metal surface. The salt film formed on a 304 stainless steel one-dimensional artificial pit electrode was preserved by flash freezing in liquid nitrogen while under an external driving potential, processed using cryo-based focused ion beam, and investigated with cryo-based scanning electron microscopy cross sectional imaging. The salt film exhibits a porous structure, with many voids and gaps between salt crystallite clusters, forming channels to provide ionic connection between the metal/film and film/solution interfaces. A spatial separation of Cr and Fe was observed in the salt film using energy dispersive X-ray spectroscopy, while Ni was found to follow the distribution of Fe, indicating the existence of co-precipitated salt containing Fe2+ and Ni2+.

Acknowledgments: This work was supported as part of the Center for Performance and Design of Nuclear Waste Forms and Containers, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0016584.
Reference

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(Invited) Novel in-Situ Methods for Real-Time Monitoring of Corrosion
Authors: Virtanen Sannakaisa 
Published: December 2020

The presentation will introduce recently developed new techniques that allow real-time monitoring of corrosion processes. The approach is based on simultaneous measurement of the cathodic kinetics of the H2 evolution reaction (HER) and the O2 reduction reaction (ORR) in real-time. The universal and non-destructive, in-situ methods based on monitoring the rates of the cathodic reactions enable the determination of sensitive, real-time corrosion rates for both atmospheric corrosion and immersion.
In the case of immersion, HER monitoring e.g. with gravimetric buoyancy H2 measurements is well established. Recently it was shown that gravimetric H2 measurements are also suitable to monitor atmospheric H2-type corrosion (for Mg alloys) [1]. A novel approach to measure HER rates during atmospheric exposure is introduced in this work. This is based on determining the pressure increase in a hermetically closed chamber with a pressure sensor. Regarding ORR, both volumetric measurements and pressure sensor based techniques are applicable to monitor the rate of consumption of O2 gas. In addition, a fibre optic O2 sensor can be employed to monitor ORR rates both under immersion and atmospheric corrosion conditions. A combination of these methods enables to monitor ORR and HER simultaneously. Therefore, also corrosion systems where both HER and ORR contribute to the cathodic reaction can be monitored (e.g., Fe and Zn corrosion). Examples for the different corrosion cases studied with this new respirometric approach will be demonstrated [2]. Combining the above described approaches with a flow cell setup expands the possible corrosion scenarios to be investigated. The flow cell enables switching between exposure conditions (such as, electrolyte composition, temperature, flow rate, etc.) with a real-time response of the corrosion rate.
In addition of being of interest for corrosion monitoring, the techniques described moreover reveal details on time-dependent mechanisms of corrosion reactions.
[1] M. Strebl, S. Virtanen, J. Electrochem. Soc. 166 (2019) C3001-C3009.
[2] M. Strebl, M. Bruns, S. Virtanen, J. Electrochem. Soc. 167 (2020) 021510.
Effect of Gradient of Soil Aeration on Corrosion Rate at Different Depths from Ground Surface
Authors: Fujihashi Kenta , Oshikawa Wataru 
Published: December 2020

In recent years, the number of photovoltaic electric power systems has drastically increased in Japan. Currently, metal piles are used in the foundations of these systems. However, a section of the metal foundation piles near the ground surface corrodes faster than . This problem has not been widely investigated.
In our study, exposure tests were carried out in soil at three test sites, and macrocell current densities were measured at different soil depths based on the gradient of soil aeration. Soil samples from these sites were collected at every 50 mm of depth below the ground surface. Thereafter, the soil samples were used as electrolytes for AC impedance analysis of the components. The exposure test indicated that there were environment in which severely corroded in soil near the ground surface, and this environment was poorly drained. However, the results of the macrocell current density measurement and the AC impedance analysis indicated that the electrode corrosion rate near the ground surface was NOT faster than, but similar to, those for the other sections in deeper soil.
Accordingly, a corrosion test was conducted by simulating the test site environment. For the corrosion test, a columnar soil tank (ϕ 200 mm × H 300 mm) and 18 steel electrodes (3.2 mm × 30 mm), each placed at 2 mm distance, were used. The macrocell current was measured using this tank of Arakita soil (paddy soil) that contained 15 wt.% water. Arakita soil used in this experiment was dried at 160 °C, milled, and passed through a sifter with 1 mm mesh net. were short-circuited. The voltage at both ends of the shunts was measured every 30 s, and the corresponding current was calculated using Ohm’s law. The spontaneous potentials of the electrodes were measured every 1 h Thereafter, AC impedance analysis of soil samples used as electrolytes that were collected from this tank at depths of ~50 mm and 250 ~ 300 mm were conducted.
The experimental results suggested that a macrocell was formed at a depth of ~10 mm. The corrosion rates of the electrodes were calculated using the macrocell current. The electrode set at a depth of 5 mm near the ground surface exhibited the maximum corrosion rate of 0.07 mm/year. The spontaneous potential of this electrode was lower than that of all other electrodes, except for two electrodes set at the depths of 40 and 45 mm. The electrode set at a depth of 5 mm was significantly corroded, which corresponded to the corrosion mass loss measured by the exposure test. AC impedance analysis. From the results, the significant corrosion at the ground surface can be considered to be due to macrocell corrosion caused by the gradient of soil aeration. However, it is not clear whether the spontaneous potentials of the electrodes at depths of 40 and 45 mm are lower and whether the anodic current flows through these electrodes.

Figure 1
Influence of Microstructure on Initial Corrosion Behavior of Steel Materials Using Kelvin Force Microscope
Authors: Uda Aimi , Yoshimoto Ryosuke , Murase Yoshiharu , Katayama Hideki , Hoshi Yoshinao , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki 
Published: December 2020

Improvement of the efficiency of power engines and reduction of the vehicles weight are important to boost the fuel efficiency of transportation equipment such as automobiles. One of the countermeasures is to expand the application of ultra-high tensile steel materials to structural members. However, the surface of ultra-high tensile steel becomes often non-uniform due to the metallographic control during manufacturing. Surface non-uniformities are more likely to lead to corrosion. Therefore, in order to further expand the application of ultra-high tensile steel materials, it is necessary to fully understand local corrosion behavior such as selective corrosion depending on the metal structure and grain boundaries. The purpose of this study is to research an influence of the non-uniformity of surface microstructure on corrosion of steel material, and the surface potential of each metallographic structures was measured by the Kelvin force microscope (KFM).
Carbon steel (S45C) was heat-treated under conditions of holding it at 1250°C for 30 minutes and cooling in the furnace. After the sample surface was mirror-polished, the sample surface was smoothed by performing ion milling as a pretreatment for the KFM measurement. The KFM measurement was conducted for a predetermined range with 0.30 Hz of a scanning frequency, and the surface shape image was also measured in AFM mode. Furthermore, a corrosion test was conducted by immersion in a borate buffer containing 0.01 mol dm-3 NaCl for 1 hour, in order to clarify the relationship between the surface potential distribution obtained by KFM measurement and the initial corrosion behavior. After that, the sample surface was thoroughly washed with distilled water, dried, and KFM measurement was performed again.
The surface morphology and the potential of the samples before the corrosion test changed periodically corresponding to the ferrite and cementite phases in pearlite. The potential of the cementite phase was about 10 mV lower than that of the ferrite phase. It was suggested that the interface between the cementite phase and the ferrite phase becomes an origin of corrosion, since the place showing the large potential difference is likely to be the starting point of corrosion. In comparing the surface morphology of the samples before and after the corrosion test, the width of the cementite phase was clearly narrower than that before the corrosion test. The surface potential of this part of the sample before the corrosion test showed more negative potential than the surroundings, which is considered that the shape change is attributed to the dissolution of the metal. Therefore, it was concluded that the potential distribution of the sample before the corrosion test is closely related to the corrosion behavior.
In-Situ Raman Analysis of Precipitates Formed By Cathodic Polarization for Study of Atmospheric Corrosion in Marine Relevant Environments
Authors: Knight Andrew , Schaller Rebecca Filardo , Katona Ryan , Bryan Charles 
Published: December 2020

Dry storage of spent nuclear fuel (SNF) in the United States exists across the country at independent fuel storage installations sites. At these sites the SNF is stored in stainless steel (SS) canisters equipped with a concrete overpack, where airflow through inlet and outlet vents allow for the passive cooling of the payload. While SS canisters are known for their enhanced corrosion resistance, when placed in a marine and near-marine environment they have shown to be suspectable to localized corrosion. In these environments, sea salt aerosols can adhere to the SS surface and, under certain temperature and relative humidity ranges, deliquescence can occur to form chloride rich brines. Under such exposure conditions, SS is known to undergo passive breakdown and pitting corrosion; thus, can be susceptible to subsequent stress corrosion cracking in the presence of residual stresses.
In this study, we explore the relationship between the cathodic polarization and the surface brine present on 304-SS. Corrosion and pitting are a function of both the anodic current demand and the available cathodic current both of which have been shown to be dependent on the environmental exposure conditions. In concentrated salt solutions, certain bulk cations (Mg2+) have a strong thermodynamic driving force to form stable precipitates, such as hydroxides, driven by an increase in pH at the cathode from corrosion reactions, which can block cathodic reduction sites. Using in-situ Raman measurements during a cathodic polarization scan we attempted to identify under which conditions (e.g., potential, pH) precipitates form and what their overall composition is. In MgCl2 rich brines, we observed that the pH of precipitation and the identity of the precipitate were dependent upon the initial MgCl2 concentration, as predicted by thermodynamic modeling. The implications of these measurements demonstrate that the maximum pit size in MgCl2 brine surface environments may be limited as the cathodic reduction sites are blocked by precipitation, perhaps leading to the starvation of the pit and eventual brine dry out.
Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Figure 1. In-situ Raman of SS in 0.189 M MgCl2 brine showing the formation of microcrystalline brucite.

Figure 1