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We evaluate the value of loan monitoring systems for a bank controlled by a micro-prudential regulator. We investigate dynamic systems (an information channel that generates information flow about quality) and static systems (where the lender receives a single signal about loan quality). We find that dynamic systems carry a regulatory charge that dominates the benefit of the systems and are therefore unprofitable, whereas static systems have positive value. Specifically, lenders can profitably dismantle their dynamic systems and instead turn to static monitoring systems. The model reveals, therefore, a potential weakness of micro-prudential regulation.

SUMMARY The massive explosive eruption of the Hunga volcano on 15 January 2022 generated atmospheric waves that were recorded around the globe and affected the ionosphere. The paper focuses on observations of atmospheric waves in the troposphere and ionosphere in Europe, however, a comparison with observations in East Asia, South Africa and South America is also provided. Unlike most recent studies of waves in the ionosphere based on the detection of changes in the total electron content, this study builds on detection of ionospheric motions at specific altitudes using continuous Doppler sounding. In addition, much attention is paid to long-period infrasound (periods longer than ∼50 s), which in Europe is observed simultaneously in the troposphere and ionosphere about an hour after the arrival of the first horizontally propagating pressure pulse (Lamb wave). It is shown that the long-period infrasound propagated approximately along the shorter great circle path, similar to the previously detected pressure pulse in the troposphere. It is suggested that the infrasound propagated in the ionosphere probably due to imperfect refraction in the lower thermosphere. The observation of infrasound in the ionosphere at such large distances from the source (over 16 000 km) is rare and differs from ionospheric infrasound detected at large distances from the epicenters of strong earthquakes, because in the latter case the infrasound is generated locally by seismic waves. An unusually large traveling ionospheric disturbance (TID) observed in Europe and associated with the pressure pulse from the Hunga eruption is also discussed. Doppler sounders in East Asia, South Africa and South America did not record such a significant TID. However, TIDs were observed in East Asia around times when Lamb waves passed the magnetically conjugate points. A probable observation of wave in the mesopause region in Europe approximately 25 min after the arrival of pressure pulse in the troposphere using a 23.4 kHz signal from a transmitter 557 km away and a coincident pulse in electric field data are also discussed.

Traditional Japanese Bizen stoneware is produced by firing a specific type of green clay in a wood-fired kiln at approximately 1200 °C. During this process, single crystalline branched dendrite-like particles of Al-substituted e-Fe2O3 (e-Fe1.7Al0.3O3) with widths and lengths of approximately 15 and 30 μm, respectively, are formed on the surface of the ceramic. Composite particles consisting of e-Fe2O3 epitaxially connected to spinel structure compounds [comprising the Fe-substituted spinel (Mg,Fe)(Al,Fe)2O4 and γ-Fe2O3)] with lengths of approximately 3 μm are also generated. The present work clarified the crystallographic relationship between e-Fe2O3 and the spinel structure compounds. In addition, brown-colored samples similar to Bizen pottery and with surface Al-substituted e-Fe2O3 particles were prepared by heating clay with K2CO3 under a 10 vol % CO gas and 90 vol % Ar gas mixture using an electric furnace instead of a firewood kiln. Hence, a traditional method was adapted to achieve the industrial production of e-Fe2O3 crystals.

The photodissociation dynamics of the heteroleptic Co(CO)3NO complex were investigated in the metal-to-carbonyl (CO) ligand charge-transfer band to compare the reactivity of the CO and nitrosyl (NO) ligands. The final state distributions of both the CO and NO fragments were measured using resonance-enhanced multiphoton ionization (REMPI) spectroscopy and velocity-map ion-imaging. The primary CO photofragment was differentiated from the secondary fragments of the subsequent unimolecular decomposition of coordinatively unsaturated intermediates by comparing the momentum distributions. The internal energy of the Co(CO)2NO intermediate was sufficiently high (≥348 kJ/mol) to be generated in the electronic excited state, indicating the occurrence of the primary CO elimination on an excited state. The NO fragments exhibited two velocity components. The analysis of the final state distributions suggested that the higher- and lower-kinetic-energy components originated from the direct primary elimination and sequential elimination, respectively. The direct photoelimination through a transiently bent ligand conformation was illustrated on the basis of a two-dimensional REMPI approach and time-dependent density functional theory calculations. The present results of both ligands demonstrate the correlation between elimination mechanisms and possible ligand conformations in the electronic excited state.

We investigated the modulation of D-region signatures due to ultra-low-frequency (ULF) waves using very-low-frequency/low-frequency (VLF/LF) radio propagation. Three transmitters from the United States (NLK, NDK, and WWVB) were received at Athabasca (ATHA), Canada. We observed oscillations in intensities and phases on the NDK-ATHA and WWVB-ATHA paths with a period of 3 to 4 minutes, associated with ULF waves during a substorm at 05:25–05:45 UT on 4 June, 2017. This is the first observational report showing clear VLF/LF oscillations in the ULF range. The ground-based H-component magnetic-field variations and Doppler velocity observed by the SuperDARN HF radars showed the same periodic changes as seen in the VLF/LF oscillations, suggesting that energetic electron precipitation (EEP) over the WWVB-ATHA and NDK-ATHA paths was modulated by the ULF waves. Based on ground-based magnetic-field data, we concluded that the ULF wave corresponded to the Pi2 pulsations associated with the substorm, because the propagation direction of the wave was westward (66.4 km/s) from the pre-midnight sector, the magnetic variations at low latitudes were inphase over wide longitudes, and the magnetic variations at ATHA slightly preceded those at low latitudes. A rising-tone chorus emission was observed in the frequency range of 5 kHz to 6 kHz at ATHA during the VLF/LF oscillations. Pitch-angle diffusion by the whistler-mode chorus wave is one possible mechanism accounting for the energetic electron precipitation.

Ultraviolet photochemistry of iron pentacarbonyl, Fe(CO)

Background Norovirus infection and Clostridioides difficile infection (CDI) are major causes of acute infectious diarrhea at medical facilities. “Geriatric intermediate care facilities” are a type of medical facility that tend to the daily life needs of elderly Japanese people. However, there is no research about norovirus- or CDI-related diarrhea at Japanese geriatric intermediate care facilities. Methods This prospective cohort study included 1445 residents at 10 geriatric intermediate care facilities in Osaka between November 2018 and October 2019. The study subjects were followed regarding the occurrence of acute infectious diarrhea and the results of rapid diagnostic tests for norovirus and CDI. We calculated incidence rates and hazard ratios (HR) with 95% confidential intervals (CI) to identify the risk factors of infectious diarrhea. Results Thirty-seven residents developed diarrhea during the observation period, although none of them was positive for norovirus or CDI. The total incidence rate was 1.21/10,000 person-days (95%CI: 0.82-1.60). Compared with residents aged 87-91 years, those aged ≤ 80 years had a significantly higher risk of diarrhea (HR = 3.85, 95%CI: 1.27-11.66). Moreover, residents with thyroid diseases had a significantly higher risk of diarrhea than those without thyroid disease (HR = 5.33, 95%CI: 2.32-12.25). Conclusions The incidence of acute infectious diarrhea is relatively low. However, residents who are < 80 years old and those with thyroid diseases are more likely to develop diarrhea. Key messages We describe the situation of acute infectious diarrhea at Japanese geriatric intermediate care facilities

Although solar activity may significantly impact the global environment and socioeconomic systems, the mechanisms for solar eruptions and the subsequent processes have not yet been fully understood. Thus, modern society supported by advanced information systems is at risk from severe space weather disturbances. Project for solar–terrestrial environment prediction (PSTEP) was launched to improve this situation through synergy between basic science research and operational forecast. The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. By this project, we sought to answer the fundamental questions concerning the solar–terrestrial environment and aimed to build a next-generation space weather forecast system to prepare for severe space weather disasters. The PSTEP consists of four research groups and proposal-based research units. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.

High-frequency Doppler (HFD) sounding is one of the major remote sensing techniques used for monitoring the ionosphere. Conventional systems for HFDs mainly utilize analog circuits. However, existing analog systems have become difficult to maintain as the number of people capable of working with analog circuits has declined. To solve this problem, we developed an alternate HFD receiver system based on digital signal processing. The software-defined radio (SDR) technique enables the receiver to be set up without the knowledge of analog circuit devices. This approach also downsizes the system and reduces costs. A highly stabilized radio system for both the transmitter and receiver is necessary for stable long-term observations of various phenomena in the ionosphere. The global positioning system disciplined oscillator with an accuracy of $${10}^{-11}$$ 10 - 11 compensates for the frequency stability required by the new receiving system. In the new system, four frequencies are received and signal-processed simultaneously. The dynamic range of the new system is wider (> 130 dB) than that of the conventional system used in HFD observations conducted by the University of Electro-Communications in Japan. The signal-to-noise ratio significantly improved by 20 dB. The new digital system enables radio waves to be received with much smaller amplitudes at four different frequencies. The new digital receivers have been installed at some of the stations in the HFD observation network in Japan and have already captured various ionospheric phenomena, including medium-scale traveling ionospheric disturbances and sudden commencement induced electric field fluctuations, which indicates the feasibility of SDR for actual ionospheric observations. The new digital receiver is simple, inexpensive, and small in size, which makes it easy to deploy new receiving stations in Japan and elsewhere. These advantages of the new system will help drive the construction of a wide HFD observation network. Graphical Abstract

The 11th Symposium on Polar Science/Ordinary sessions: [OS] Space and upper-atmosphere sciences, Poster presentations, Mon. 16 Nov. - Fri. 18 Dec.

This chapter studies the impacts of market concentration on risk-prevention incentives by closely observing the changes in the price and quantity in the hard disk drive (HDD) industry before and after the 2011 Thailand floods. The combination of high price and low quantity persisting after the floods indicates that the floods triggered the formation of a de facto cartel, and a shift in demand for hard disk drives alone is unable to explain the observed combination.

Is opposition to immigration deeply entrenched or is it open to updating in the face of new information? We explore this question by examining how attitudes of native citizens shift following exposure to information that points to potential upsides of immigration. We do so using a large-scale randomized experiment embedded in a text-comprehension study administered in Japan. As part of the study, participants were subtly presented with information on social and economic problems that immigration could help address (e.g., growing elderly population that requires care, labor shortage in certain sectors). Depending on the treatment, information exposure increased support for a more open immigration policy and motivated pro-immigration political action. Notably, effects persisted 10-12 days after the intervention. The results suggest that information campaigns can lessen public opposition to immigration.

While recall errors in retrospective data from household surveys may generate estimation biases, the nature and the relative magnitude of the errors are still largely unknown, especially in...

Using 630 nm airglow data observed by an airglow imager on the International Space Station (ISS), the occurrence of equatorial plasma bubbles (EPBs) is studied. In order to examine the physical mechanisms in the boundary region between the Earth and the outer space, an ionosphere, mesosphere, upper atmosphere, and plasmasphere mapping (IMAP) mission had been conducted onboard the ISS since October 2012. The visible light and infrared spectrum imager (VISI) is utilized in the ISS-IMAP mission for nadir-looking observation of the earth’s atmospheric airglow. In this study, we automatically select EPBs according to the criterion for extracting the tilted dark lines from VISI data. Using the selected events, the dependence of the occurrence rate of EPBs is examined. There is no other report of the occurrence rate of EPBs using downward-looking visible airglow data (630 nm). In this result, the occurrence rate is high at all longitudes in the equinoctial seasons. In the solstice seasons, in contrast, the occurrence rate is very small especially in the Pacific and American sectors. This result is basically consistent with previous studies, e.g., those determined by plasma density data on DMSP satellites.During the June solstice in 2013, EPBs were observed in association with geomagnetic storms that occurred due to a southward turning of the IMF Bz. Using these events, we examined the storm-time features of the occurrence of EPBs in the Pacific-American sectors during the June solstice. In these sectors, where the occurrence rate of EPBs is very small during solstice seasons, some EPBs were observed in the peak and recovery phases of the storms. This result shows that the prompt penetration of electric fields causes the development of EPBs, in the data we analyzed, the geomagnetic storms did not inhibit the generation of EPB in the Pacific–American sectors.

Ultraviolet photodissociation dynamics of tricarbonylnitrosylcobalt, Co(CO)3NO, is studied by ion-imaging. The photon energy is large enough to eliminate both NO and CO ligands in this heteroleptic complex, among which state-specific scattering is observed in the NO loss channel. The velocity distributions of the NO ligands exhibit clear evidence of two pathways. NO fragments with higher and lower kinetic energies are ascribed to direct dissociation in the electronic excited state and secondary decomposition following relaxation processes, respectively. The state-specific angular distribution of the faster component corroborates the rotational alignment, indicating the bent coordination of the nitrosyl ligand in the photoexcited state.

HF-START is HF Simulator Targeting for All-users’ Regional Telecommunications. This paper addresses the problems of worldwide existing radio propagation model and challenge on developing the HF-START. Its possible extension in the future is discussed. Meteorological information for aircraft in flight is broadcasted from worldwide radio stations in the frequency range of 3–15 MHz. Such frequency range is strongly affected from day-to-day bottom structure variation of the Earth’s ionosphere, where it is influenced by both space weather and upper atmosphere activities. Space weather is thus significant to aeronautical users, who deal with the critical radio application. Space weather data is, however, difficult to be understood. To translate research level data to user level data, radio propagation simulator named HF-START is being developed. Space weather disturbances-triggered failure of communications/navigation is of high priority to forecast.

The highly rotationally excited states in the A 2 Σ + - X 2 Π Ω band of NO were investigated by laser-induced fluorescence and multi-photon ionization spectroscopy. The rotational states with J up to 80.5 were prepared by CH3ONO photodissociation in the S1 and S2 excited states for spectroscopic measurements. In total, 3890 lines of nine vibronic bands were analyzed. The observed line positions deviated from the values calculated using the previous molecular constants as J increased in the J > 50.5 region. The sextet-order centrifugal distortion constants were determined for the A 2 Σ + and X 2 Π Ω states so that the transition frequencies associated with the high-J states could reproduce the observed results within the experimental accuracy. The band origin values, whose errors have been discussed in previous studies, were refined in the present analysis. The experimental condition to suppress the rotational relaxation of the high-J states was examined, enabling us to determine the higher-order centrifugal distortion constants.

Aim The aim of this study was to identify factors affecting the final diagnosis of cough. Materials and methods This study recruited 463 consecutive patients who visited five Japanese general hospitals due to cough from October 2006 to September 2007. Of these, 418 patients (90%) who completed a questionnaire designed to acquire data regarding clinical manifestations of cough were included. Results Most patients with bronchial asthma had cough with seasonal variation and wheezing. Patients with gastro esophageal reflux disease suffered from heartburn and cough without daily or seasonal variation. Cough associated with sinobronchial syndrome was only observed in females and was linked to increased sputum. Patients with whooping cough were bothered by cough interrupting sleep and talking. Patients with cardiogenic cough had exertional dyspnea. Conclusion The specific items on our questionnaire relating to patient characteristics, complications, and triggers of cough, represent useful tools for diagnosing the primary disease producing cough.

A fast breeder reactor (FBR) is considered as the promising technology in terms of load reduction on the environment, because the FBR has capability to improve usage efficiency of uranium resources and can reduce high-level radioactive waste which needs to be managed for millions of years. A cold trap is one of the important components in the FBR to control the impurity concentration of the liquid sodium. For accurate evaluation of the cold trap performance, we have been proposing the three-dimensional (3D) numerical analysis method of the cold trap. In this method, the evaluation of the impurity precipitation phenomena on the surface of the mesh wire of the cold trap is the key. For this, the numerical analysis method which is based on the lattice kinetic scheme (LKS) has been proposed. In order to apply the LKS to the impurity precipitation simulation of the cold trap, two models (the low Reynolds number model and the impurity precipitation model) have been developed. In this paper, we focused on the validation of these models. To confirm the validity of the low Reynolds number model, the Chapman–Enskog analysis was applied to the low Reynolds number model. As a result, it has been theoretically confirmed that the low Reynolds number model can recover the correct macroscopic equations (incompressible Navier–Stokes equations) with small error. The low Reynolds number model was also validated by the numerical simulation of two-dimensional (2D) channel flow problem with the low Reynolds number conditions which correspond to the actual cold trap conditions. These results have confirmed that the error of the low Reynolds number model is ten times smaller than that of the original LKS. The validity of the impurity precipitation model was investigated by the comparison to the precipitation experiments. In this comparison, the mesh convergence study was also conducted. These results have confirmed that the proposed impurity precipitation model can simulate the impurity precipitation phenomena on the surface of the mesh wire. It has been also confirmed that the proposed impurity precipitation model can simulate the impurity precipitation phenomenon regardless of the cell size which were tested in this investigation.

HF-START (HF Simulator Targeting for All-users' Regional Telecommunications) is a user-friendly simulator developed to meet the needs of space weather users. Because prediction of communications failure due to space weather disturbances is of high priority and must be reliable, HF-START is necessary to be evaluated. A simple and low cost prototype of software defined radio (SDR) based digital receiver is developed for the HF experiment to evaluate the HF-START during the field campaign. The field campaign employs the receiver prototype in addition to existing domestic ionospheric observations in Japan. The experiment allows analyzing the effect of the ionosphere on radio propagation delay. The first experiment has proven the capability of the low cost prototype as its result showed very good signal quality with loud and clear playback ability. Extending similar experiment to Southeast Asia is planned.

This paper presents the shadow capital asset pricing model (CAPM) of Ma [2011a. Advanced Asset Pricing Theory. London: Imperial College Press] as an intertemporal equilibrium asset pricing model, and tests it empirically. In contrast to the classical CAPM – a single-factor model based on a strong behavioral or distributional assumption – the shadow CAPM can be represented as a two-factor model, and only requires a modest behavioral assumption of weak form mean-preserving spread risk aversion. The empirical tests provide support in favor of the shadow CAPM over the classical CAPM, the consumption CAPM, or the Epstein and Zin [1991. “Substitution, Risk Aversion and the Temporal Behavior of Consumption and Asset Returns: An Empirical Analysis”. Journal of Political Economy 99, 263–286] model. Moreover, the shadow CAPM provides a consistent explanation for the cross-sectional variations of expected returns on the stocks and for the time-varying equity premium.

Many studies have reported that ionospheric disturbances occur after big earthquakes. One of the causes of these coseismic ionospheric disturbances (CIDs) is the infrasound wave excited by Rayleigh wave propagated on the ground from the epicenter. The infrasound wave propagates upward and produces CIDs. In this study, using HF Doppler sounding system (HFD), CIDs at the different altitudes associated with the foreshock of Tohoku Earthquake were examined.

Because of the reactor core characteristics of fast breeder reactors (FBRs), liquid sodium must be used for the reactor core cooling. Small amounts of oxygen and hydrogen are dissolved in the FBR sodium coolant. To decrease those impurity concentrations, cold traps (CTs) are installed in the primary and secondary systems. CTs are a purification apparatus universally used in FBR sodium systems to maintain the oxygen and hydrogen concentration levels in sodium within acceptable limits. CTs can capture oxygen and hydrogen as sodium compounds by packing materials with stainless steel wires using precipitation phenomenon (crystallization) by decreasing the inlet sodium temperature below the saturation temperature. Oxygen and hydrogen are precipitated as Na2O and NaH. We have been developing an evaluation method of the impurity capturing capacity in CTs. In this study, we investigated the impurity capturing capacity of CTs through three-dimensional computational fluid dynamics (CFD) analysis. We also used CFD analysis to evaluate the time variation of the pressure loss of packing material. The amount of precipitation was decided from the temperature, concentration and velocity distributions through the CFD analysis. First, a uniform wire mesh was used for the capturing capacity analysis in the CTs. Precipitation speed was higher for the hydrogen sodium compound than for the oxygen sodium compound. As sodium flowed from the outer to the inner side of the packing material, the hydrogen sodium compound was precipitated near the outer surface of the CTs and that blocked the sodium flow at the outer surface. As a result, if a lot of the hydrogen flowed into the CTs, the inner side of the wire mesh could not be used effectively. Second, we also proposed non-uniform wire meshed shapes and analyzed their capturing capacity in the CTs. The shape of the wire mesh was changed in the radial direction. A coarse meshed wire was placed on the outer side of the packing material and a closely packed meshed wire was placed on the inner side. Our CFD results showed that the most effective impurity capturing capacity of hydrogen sodium compound could be obtained by changing the precipitation speed and wire shape in the radial direction.

A cold trap is one of the important components in the Fast Breeder Reactor (FBR) to control oxygen and hydrogen concentration of liquid sodium. For more accurate evaluation of the cold trap performance, we have started a research program to develop the evaluation method based on the 3D numerical analysis. Our evaluation method consists of two steps: one is a numerical analysis of sodium compound deposition on the mesh wires; the other is a numerical analysis of the sodium flow in the cold trap where the effect of the sodium compound deposition is considered as local pressure loss increment. In this study, we have focused on the development of the numerical analysis method of the sodium compound deposition on the mesh wires of the cold trap. As a numerical method, we have adopted the lattice Boltzmann method which is known to be useful for the flow simulation around the complex geometry like the mesh wires. In order to apply the lattice Boltzmann method to the sodium compound deposition simulation around the mesh wire, we proposed a low Reynolds number model and an impurity precipitation model for the conventional lattice Boltzmann method. The low Reynolds number model was validated by a comparison with a theoretical solution of the two-dimensional channel flow. To validate the impurity precipitation model, we conducted a precipitation experiment by using the supersaturated sucrose in the water instead of the liquid sodium with the oxygen and the hydrogen. The comparison between the experiment and the simulation showed good agreement regarding the pressure loss increment. From these results, we confirmed the accuracy of the low Reynolds number model and the impurity precipitation model. The accuracy of our models in the sodium condition will be confirmed in the future study.

W-band 95GHz Doppler radar named FALCON-I was developed and operated for cloud observations. High spacial and high velocity resolution are achieved with low transmitting power of millimeter wave. FALCON-I can observe not only clouds and precipitations but also flying small objects such as birds, insects, seeds of plants, and volcanic ashes in the atmosphere.

In this work, we successfully developed bacterial templates on the surface of an overoxidized polypyrrole film using both gram-negative and gram-positive bacteria in which bacterial surface chemical structures are precisely transferred at a molecular level. The sensor film identified target bacteria within minutes through a unique combination with dielectrophoresis. The bacterial cavities had high selectivity for distinguishing specific target bacteria in bacterial mixtures containing gram-negative (Escherichia coli and Pseudomonas aeruginosa) and gram-positive (Bacillus subtilis and Staphylococcus aureus) bacteria. This rapid and specific recognition system will enable not only bacterial sensing but also analysis of various biological species.

The effect of inorganic chlorides on volatilization of lead compounds from CaO–SiO 2 –Al 2 O 3 molten slag under simulating conditions of gasification and melting of municipal solid waste was studied. It was found from the experiments that the volatilization of lead compounds from CaO (30 wt.%)–SiO 2 (50 wt.%)–Al 2 O 3 (20 wt.%) molten slag in a lab-scale electric furnace at 1773 K in N 2 , N 2 –O 2 or N 2 –CO–CO 2 atmosphere was promoted by the addition of NaCl, KCl and CaCl 2 to the slag containing PbO, in the order of CaCl 2 > NaCl > KCl. The rate of volatilization and the amount of volatilized lead compounds were the highest by employing CaCl 2 in N 2 –CO–CO 2 atmosphere, due to combined reduction of PbO to metallic lead (Pb) and chlorination of PbO to PbCl 2 . By heating the molten slag at 1773 K for about 10 min, almost 100% of PbO was removed by adding CaCl 2 to the slag at a molar ratio of (Cl)/(Pb) = 27. However, the heating of molten slag at 1773 K for 10 min was not sufficient for complete removal of PbO, even by adding an excessive amount of NaCl and KCl to the slag at a higher molar ratio of (Cl)/(Pb) = 110. From the equilibrium calculations on the main elements involved in municipal solid waste in shaft-type gasification/melting furnace, almost 100% of lead compounds were predicted to volatilize as Pb, PbS and PbCl 2 . The ratio of PbCl 2 increased with the increase in chlorine (Cl) content in the waste. It was considered by equilibrium calculations that increased volatilization of lead compounds was attributed to the pronounced formation of PbCl 2 by the reaction of PbO with HCl which was released from NaCl, KCl and CaCl 2 .

This paper studies the effects of advertising in a Bertrand duopoly model, which extends Grossman and Shapiro (1984) by introducing the spillover advertising effect on top of the direct advertising effect. It is shown that the spillover effects would make the environment more monopolistic: higher prices and lower demand.

Low carbon steels containing Si of 0.1 and 1.0 mass%, and 99.5 mass% pure Fe were oxidized in laboratory air and in a H2O-containing atmosphere at 1173 K. Acoustic emission technique was used to assess the temperature (TF) at which the first major scale failure takes place during cooling. TF of 1.0 %Si steel oxidized in the air was found to increase with an increase in the scale thickness and cooling rate, while TF of 0.1 %Si steel had almost no dependence on these parameters. Moreover, the values of TF of both the steels oxidized in the H2O-containing atmosphere are higher than those in the air. These differences are attributable to the cooling rate, scale structure, and eutectoid reaction. In general, higher cooling rate implies a higher strain rate and there may be a larger temperature gradient across the scale thickness, which additionally enhances the scale failure. The metallographic examinations revealed that eutectoid magnetite particles in the scales formed on 0.1 %Si steel coarsen as the cooling rate decreases and magnetite seam was formed at the bottom of the iron oxide layer. It is clear that the influence of magnetite precipitation increases as the cooling rate decreases and thus the stress in the scale increases.