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Shweder et al. (1997) proposed the three domains of morality: Autonomy, Community, and Divinity. This study used situation sampling to explore how people from Japan and the U.S. interpret moral transgressions provided in their own and another cultural context. Specifically, the analysis tested whether participants with one cultural background recognize culturally congruent moral transgressions as violations more frequently and feel more harshly towards them than culturally incongruent domains. Furthermore, the extent of evocation caused by the home and another culture was investigated. This study asked 102 Japanese and 168 U.S. participants to judge which domain would be primarily involved in each transgression and to rate their wrongness. Participants showed a higher perceived magnitude of transgressions in culturally valued domains provided by in-group than outside members. Cross-cultural differences in morality and future directions are discussed. [ABSTRACT FROM AUTHOR]

The Moral Foundations Dictionary (MFD) is a useful tool for applying the conceptual framework developed in Moral Foundations Theory and quantifying the moral meanings implicated in the linguistic information people convey. However, the applicability of the MFD is limited because it is available only in English. Translated versions of the MFD are therefore needed to study morality across various cultures, including non-Western cultures. The contribution of this paper is two-fold. We developed the first Japanese version of the MFD (referred to as the J-MFD) using a semi-automated method—this serves as a reference when translating the MFD into other languages. We next tested the validity of the J-MFD by analyzing open-ended written texts about the situations that Japanese participants thought followed and violated the five moral foundations. We found that the J-MFD correctly categorized the Japanese participants’ descriptions into the corresponding moral foundations, and that the Moral Foundations Questionnaire (MFQ) scores correlated with the frequency of situations, of total words, and of J-MFD words in the participants’ descriptions for the Harm and Fairness foundations. The J-MFD can be used to study morality unique to the Japanese and also multicultural comparisons in moral behavior. [ABSTRACT FROM AUTHOR]

Joint go and no-go effects (joint Simon effects; JSEs) are considered to have a stimulus–response compatibility effect on joint reaction time tasks (joint Simon task) caused by the presence of other people. Additionally, JSEs are known to be associated with various social factors and are therefore a potential clinical marker for communicative function; however, the relationship with the personality that is associated with communication skills remains unclear. In this study, we focused on the association between JSE and personality traits. Thirty Japanese participants (fifteen women) were recruited. First, personality trait scores were obtained using the Japanese version of the ten-item personality inventory before the experiment. Second, we measured reaction times in the joint Simon task and single go and no-go tasks with the go signal presented on the congruent and incongruent sides. At last, we analyzed the association between reaction times and personality traits by using Spearman's correlation analysis. As a result, we observed two pairs with significant correlations: JSE and neuroticism and short reaction times in the joint condition and agreeableness. In conclusion, we identified potential psychological markers associated with the joint Simon task. These findings may lead to an additional hypothesis regarding the neurobiological mechanisms of JSEs. [ABSTRACT FROM AUTHOR]

Background: The involvement of cholesterol crystals (CCs) in plaque progression and destabilization of atherosclerotic plaques has been recently recognized. This study aimed to evaluate the association between the intraplaque localization of CCs and plaque vulnerability. Methods: We investigated 55 acute coronary syndrome (ACS) and 80 stable angina pectoris (stable AP) lesions using optical frequency domain imaging (OFDI) prior to percutaneous coronary intervention. The distance between CCs and the luminal surface of coronary plaques was defined as CC depth. Results: Although the incidence of CCs had similar frequencies in the ACS and stable AP groups (95% vs. 89%, p = 0.25), CC depth was significantly less in patients with ACS than in those with stable AP (median [25th to 75th percentile]: 68 μm [58 to 92 μm] vs. 152 μm [115 to 218 μm]; p < 0.001). The incidences of plaque rupture, thrombus, lipid-rich plaques, and thin-cap fibroatheroma were significantly greater in patients with ACS than in those with stable AP (62% vs. 18%, p < 0.001; 67% vs. 16%, p < 0.001; 84% vs. 57%, p < 0.01; and 56% vs. 19%, p < 0.001, respectively). Conclusion: OFDI analysis revealed that CCs were found in the more superficial layers within the coronary atherosclerotic plaques in patients with ACS than in those with stable AP, suggesting that CC depth is associated with plaque vulnerability. CC depth, a novel OFDI-derived parameter, could be potentially used as an alternative means of evaluating plaque vulnerability in coronary arteries. [ABSTRACT FROM AUTHOR]

Abstract: Spinning detonations propagating in a circular tube were numerically investigated with a two-step reaction model by Korobeinikov et al. The time evolutions of the simulation results were utilized to reveal the propagation behavior of single-headed spinning detonation. Three distinct propagation modes, steady, unstable, and pulsating modes, are observed in a circular tube. The track angles on a wall were numerically reproduced with various initial pressures and diameters, and the simulated track angles of steady and unstable modes showed good agreement with those of the previous reports. In the case of steady mode, transverse detonation always couples with an acoustic wave at the contact surface of burned and unburned gas and maintains stable rotation without changing the detonation front structure. The detonation velocity maintains almost a CJ value. We analyze the effect of acoustic coupling in the radial direction using the acoustic theory and the extent of Mach leg. Acoustic theory states that in the radial direction transverse wave and Mach leg can rotate in the circumferential direction when Mach number of unburned gas behind the incident shock wave in the transverse detonation attached coordinate is larger than 1.841. Unstable mode shows periodical change in the shock front structure and repeats decoupling and coupling with transverse detonation and acoustic wave. Spinning detonation maintains its propagation with periodic generation of sub-transverse detonation (new reaction front at transverse wave). Corresponding to its cycle, whisker is periodically generated, and complex Mach interaction periodically appears at shock front. Its velocity history shows the fluctuation whose behavior agrees well with that of rapid fluctuation mode by Lee et al. In the case of pulsating mode, as acoustic coupling between transverse detonation and acoustic wave is not satisfied, shock structure of spinning detonation is disturbed, which causes failure of spinning detonation. [Copyright &y& Elsevier]

Abstract: Pulsating detonations propagating in circular and square tubes were numerically investigated with a two-step reaction model by Korobeinikov et al. The time evolution of the simulation results was utilized to reveal the propagation mechanism of pulsating detonation. Soot track images on the wall and flow features shows cyclic behavior in longitudinal direction including three regions of multi-headed, single-headed, and no detonation. Pulsating detonation shows strong oscillation in the longitudinal direction and periodic behavior as follows. Shock front separates from the reaction front, and the shock wave velocity becomes underdriven. Local explosion occurs near the flame front and develops on inner detonation propagating to the leading shock wave. After penetration of the inner detonation into the leading shock wave, an overdriven multiheaded detonation appears and is gradually transformed into a spinning detonation with diminishing velocity. After a while, the spinning detonation decays, and the shock front finally separates from the reaction front again. Pulsating detonation propagates with repetition of these processes and its velocity varies from underdriven to overdriven in one cycle of pulsation. In order to discuss the one-dimensional features of pulsating detonation, x–t diagrams of cross-sectionally averaged profile are directly compared with x–t diagram of one-dimensional detonation, and the two agree well in terms of periodicity, as observed in the unsteady mechanism of the large-disturbance regime. Characteristic values such as the velocity in the failed regime obtained by the one-dimensional detonation agree with those by the pulsating detonation in circular and square tubes. Therefore, pulsating detonation is essentially a one-dimensional phenomenon and is dominant to longitudinal instability. [Copyright &y& Elsevier]

Brown rice-added breads were prepared with and without crude and purified Aspergillus niger phytase preparations. By adding 30% (w/w) brown rice flour and no phytase preparation, the phytate (myo-inositol hexaphosphate; IP6) content of the bread was increased and the loaf volume was reduced. The direct addition of a food-additive grade phytase preparation (3,000 U) resulted in a significant decrease in the IP6 content. However, it collapsed the bread crust. The crude phytase preparation had significant protease and amylase activities. A simple chromatographic method for the separation of phytase activity from the protease and amylase activities was developed. By using purified phytase, the IP6 content was reduced without any adverse effects on the rising of the bread, which indicates that protease and amylase may be responsible for the collapse of the crust by the commercial phytase preparation. PRACTICAL APPLICATIONS Phytate in unrefined cereals and beans lowers bioavailability of minerals. On the other hand, these materials are rich in health-promoting components. To reduce the phytate in them during processing, some commercially available phytase preparations are now used. However, we found that such preparation contains significant amylase and protease activities, which may cause adverse effect on the appearance and textural properties of final products. To solve these problems, a simple and inexpensive procedure for separation of phyatase from amylase and protease was developed in the present study. The purified phytase can reduce phytate in brown rice-added bread without adverse effect on rising of bread. These results would encourage prepare the phytase preparation in high purity in an industrial scale to improve nutritional value of unrefined cereal- and bean-based functional foods. [ABSTRACT FROM AUTHOR]

The features of one-dimensional unsteady detonations are studied numerically using a hydrogen-air detailed chemical reaction model. A series of simulations are carried out while degree of overdrive, initial pressure, initial temperature, and equivalence ratio are varied. The oscillation modes and mechanisms of the one-dimensional detonations are discussed with reference to shock pressure histories and x-t diagrams of density distributions. As the degree of overdrive is reduced with a stoichiometric mixture of hydrogen-air at P0=0.421 atm and T0=293 K, a steady state appears, along with a high-frequency mode and a low-frequency mode. The oscillation mechanism of the high-frequency mode is the same as that of the regular regime of unsteady shock-induced combustion observed around a spherical projectile flying at hypersonic velocity in detonable gases. The degree of overdrive threshold between the steady and unsteady region increases monotonically with initial pressure and decreases monotonically with initial temperature. When the equivalence ratio is changed, the threshold has a minimum value around [lowercase_phi_synonym]=1. We focus attention on a nondimensional effective activation energy, which is generally used for linear stability analysis. The oscillation mode depends highly on the nondimensional effective activation energy. The oscillation of the detonation front appears as the nondimensional effective activation energy goes past a threshold value of 5.2. Furthermore, we investigate the failed regime and possible reignition in this regime. In the failed regime, a detonation wave breaks up into a leading shock, a contact discontinuity, and a rarefaction wave. When the shock is weak, reignition time becomes very long. Therefore, the reignition after the failed regime is difficult to reproduce in the restricted computational domain. The reignition process in the failed regime is investigated by means of analysis consisting of integration along the point of intersection between a Rayleigh line for weak leading shock and a partially burnt Hugoniot curve. The reignition time increases dramatically with decreasing temperature behind the shock wave, when the gas condition goes past the second explosion limit. The second explosion limit is one of the characteristics of the hydrogen-air detailed chemical reaction model and does not exist in the one-step chemical reaction model. Lastly, the reignition time obtained by the analysis is compared with that obtained by the simulation results. The simulation results agree well with the analytical results. [ABSTRACT FROM AUTHOR]

The oscillation mechanism and reignition process of one-dimensional unsteady detonations are numerically studied using a one-step chemical reaction model governed by Arrhenius kinetics. A series of simulations, without perturbations from the outflow boundary to the detonation front, are carried out while the degree of overdrive, f, is varied between 1.10 and 1.74 (f = D²/D²[sub CJ]; where D is detonation velocity). Shock pressure histories and x-t diagrams are utilized in order to attain precise understanding of the one-dimensional unsteady detonations. At higher degrees of overdrive, f = 1.40-1.74, shock pressure histories agree with those of previous studies. The oscillation mechanism is the same as that of the large-disturbance regime of unsteady shock-induced combustion around a projectile. At lower degrees of overdrive, f < 1.30, grid resolution affects the eventual results, because half reaction time in the shock pressure exhibits considerable variation. Four typical kinds of oscillation pattern are discussed and are explained by their x-t diagrams and shock pressure histories. Each oscillation mechanism is essentially the same as that of the large-disturbance regime. The reignition process in the failed regime was numerically investigated at f = 1.01-1.25. The reignition points tend to converge on a specified point in study of grid refinement, although the oscillation of the shock pressure histories becomes chaotic, suggesting the existence of a unique solution for reignition. All the simulation results for f = 1.01-1.20 show the failed regime after initial disturbance at the early stage. The failed regime is compared with the solution of the Riemann problem, and analysis consisting of a Rayleigh line for weak leading shock and a partially burnt Hugoniot curve is adopted. Analysis suggests the concept of partial chemical heat release, indicating the possibility of discontinuous change in conditions, and, indeed, simulation indicates occurrence... [ABSTRACT FROM AUTHOR]

Proposes an effective nondimensional parameter, referred to as the first Damkohler parameter, to quantitatively classify the unsteady flow regime of shock-induced combustion around a hypervelocity spherical projectile. Development of a prediction method; Computational study for validation; Results of the study.

Studies the flow features of an unsteady shock-induced combustion around projectiles using a series of simulations of an oxygen-hydrogen reaction mechanism. Mechanism of the unsteady combustion around hypersonic projectiles; Characterization of the combustion; Mechanism of the wave interaction on the stagnation streamline; Mechanisms for the large-disturbance regime.

Background: Acute asthma exacerbation in children is often caused by respiratory infections. In this study, a coordinated national surveillance system for acute asthma hospitalizations and causative respiratory infections was established. We herein report recent trends in pediatric acute asthma hospitalizations since the COVID‐19 pandemic in Japan. Methods: Thirty‐three sentinel hospitals in Japan registered all of their hospitalized pediatric asthma patients and their causal pathogens. The changes in acute asthma hospitalization in children before and after the onset of the COVID‐19 pandemic and whether or not COVID‐19 caused acute asthma exacerbation were investigated. Results: From fiscal years 2010–2019, the median number of acute asthma hospitalizations per year was 3524 (2462–4570), but in fiscal years 2020, 2021, and 2022, the numbers were 820, 1,001, and 1,026, respectively (the fiscal year in Japan is April to March). This decrease was observed in all age groups with the exception of the 3‐ to 6‐year group. SARS‐CoV‐2 was evaluated in 2094 patients from fiscal years 2020–2022, but the first positive case was not detected until February 2022. Since then, only 36 of them have been identified with SARS‐CoV‐2, none of which required mechanical ventilation. Influenza, RS virus, and human metapneumovirus infections also decreased in FY 2020. In contrast, 24% of patients had not been receiving long‐term control medications before admission despite the severity of bronchial asthma. Conclusion: SARS‐CoV‐2 was hardly detected in children with acute asthma hospitalization during the COVID‐19 pandemic. This result indicated that SARS‐CoV‐2 did not induce acute asthma exacerbation in children. Rather, infection control measures implemented against the pandemic may have consequently reduced other respiratory virus infections and thus acute asthma hospitalizations during this period. However, the fact that many hospitalized patients have not been receiving appropriate long‐term control medications is a major problem that should be addressed. [ABSTRACT FROM AUTHOR]

Is intention, even if unfulfilled, enough to make a person appear to be good or bad? In this study, we investigated the influence of unfulfilled intentions of an agent on subsequent moral character evaluations. We found a positive-negative asymmetry in the effect of intentions. Factual information concerning failure to fulfill a positive intention mitigated the morality judgment of the actor, yet this mitigation was not as evident for the negative vignettes. Participants rated an actor who failed to fulfill their negative intention as highly immoral, as long as there was an external explanation to its unfulfillment. Furthermore, both emotional and cognitive (i.e., informativeness) processes mediated the effect of negative intention on moral character. For the positive intention, there was a significant mediation by emotions, yet not by informativeness. Results evidence the relevance of mental states in moral character evaluations and offer affective and cognitive explanations to the asymmetry. [ABSTRACT FROM AUTHOR]

To analyze non-ideal phenomena, such as burned gas backflow and non-detonation combustion, which affect the rotating detonation wave Mach number, simultaneous self-luminous visualization, time-averaged static pressure, fluctuating pressure, and thrust measurements with gaseous ethylene and oxygen were performed. Consequently, by doubling the number density of the fuel injectors, the hydrodynamic blockage ratio at the oxidizer inlet increased approximately 1.7-fold under the same oxidizer inlet area conditions. This may be attributed to the increase in the detonation propagation Mach number owing to the enhanced mixing of fuel and oxidizer. The relationship between the parasitic combustion fraction in front of the rotating detonation wave and the Mach number was also investigated by using a distributed heat release model. Consequently, it was suggested that experimental Mach number decreased from approximately 4.1 to 2.8 with increase in a mixture mass flux, and the theoretical detonation wave propagation Mach number was 7.3. • Mach number of rotating detonation wave was experimentally estimated. • Hydrodynamic blockage ratio increased with number density of fuel injectors. • Propagation speed of detonation wave increased with mixture mass flux. • Fluctuating pressure ratio decreased with increase in mixture mass flux. • The Mach number decreased from 4.1 to 2.8 with increase in mixture mass flux. [ABSTRACT FROM AUTHOR]

• A longer and denser layer of the water droplets further mitigated the blast wave. • Heat transfer absorbed a part of the energy and directly mitigated the blast wave. • The quasi-steady drag divided the shock wave into transmitted and reflected ones. • The division reduced the energy carried by the blast wave and mitigated it. • Multilayers of water droplets synergistically improve the blast-mitigation effect. The blast mitigation mechanism of a water droplet layer was numerically studied, considering convective heat transfer and quasi-steady drag. The propagation of a one-dimensional blast wave in a shock tube was modeled, leading to momentum and energy transfer between the water droplets and the air. Convective heat transfer absorbed part of the energy, thereby directly mitigating the blast wave. Although the quasi-steady drag transferred less energy than the convective heat transfer, it exhibited greater blast mitigation. Thus, a parametric study using characteristic values and describing the water droplet layer was conducted to examine the blast mitigation mechanisms involved in the quasi-steady drag, aside from the energy absorption effect. It was determined that each time the shock wave reached the air/water droplet interface, the quasi-steady drag divided the wave into transmitted and reflected waves. Because the one-dimensional blast wave helped to carry some of the energy, the division reduced the energy carried by the incident blast wave, resulting in its mitigation. Finally, the blast mitigation effect of multilayers was compared with that of a single layer. The result showed that increasing the number of layers synergistically improved the blast mitigation effect by dividing the shock wave multiple times. [ABSTRACT FROM AUTHOR]

Liquid propellants are commonly used in rocket engines due to their high energy density. In this study, we focused on the use of liquid ethanol and liquid nitrous oxide as propellants in a cylindrical rotating detonation engine (RDE) for practical applications, and examined the effects of various conditions on the bipropellant RDE performance. We varied the vapor quality of nitrous oxide in a mixture of liquid and gaseous nitrous oxide due to the flash boiling. In addition, we varied the liquid ethanol temperature, the injector stiffness, and momentum angle of the propellant. We then analyzed the effects of these changes on the propagation mode of the RDE under atmospheric pressure conditions. The results showed that a rotating detonation wave was observed under the combination of high vapor quality of nitrous oxide, high injector stiffness, high liquid ethanol temperature, and high momentum angle. The propagation velocity was obtained as 73∼83 % of the Chapman-Jouguet velocity. Long-duration combustion tests were also conducted, and the internal combustion structure was confirmed from the erosion of the carbon-carbon (C/C) composite material. The detonation wave was considered to propagate near the bottom of the RDE with liquid propellants from the erosion heights of the C/C composite. The erosion height was confirmed to be consistent with the fill height calculated using the sound speed of the nitrous oxide. In addition, characteristic exhaust velocity efficiencies of more than 85 % were achieved in all combustion tests. [ABSTRACT FROM AUTHOR]

Abstract: Spherical projectiles were launched into detonable mixtures over a wide range of projectile velocities from near to about 1.8 times the Chapman–Jouguet (C–J) velocity. Oblique detonation waves (ODWs) and shock-induced combustions (SICs) stabilized around the projectiles were visualized with high time and high spatial resolutions using the Schlieren technique and a high-speed camera with a 1-μs frame speed. Unsteady wave structures called Straw Hat type structures consisting of a SIC region followed by a C–J ODW were observed near stabilizing criticalities of a C–J ODW, and they were divided into two propagation types, depending on whether the C–J ODW could be stabilized . In the present study, we suggested wave structures of the Straw Hat types based on our examination of dozens of continuous images. Triple points were observed at the intersection of a bow shock, a C–J ODW and a transverse detonation or shock wave when projectile velocities were slightly higher than C–J velocities. Onsets of local explosions in the SIC region for stabilizing the ODW in the Straw Hat type structures have been reported . We observed this stabilizing mechanism by visualizing onsets of periodical local explosions and their transition to spherical detonation waves when the projectile velocity was much higher than the C–J velocity. We also determined stabilizing criticalities using a stoichiometric acetylene-oxygen mixture diluted with argon or krypton in 50% or 75% volumetric fractions, respectively. We found that the stabilizing criticalities did not depend only on the ratio of the projectile diameter and the cell size of the mixture. [Copyright &y& Elsevier]

Gas dynamics in a simplified pulse detonation engine (PDE) was theoretically analyzed. A PDE was simplified as a straight tube with a fixed cross section. One end of the tube was closed, namely, this end was the thrust wall, and the other end was open. A detonation wave was initiated at the closed end and simultaneously started to propagate toward the open end. When the detonation wave broke out from the open end, a rarefaction wave started to propagate from the open end toward the closed end. This rarefaction wave was reflected by the closed end. By considering this rarefaction wave to be self-similar in the analysis of the interference between this rarefaction wave and its reflection from the closed end, we analytically formulated the decay portion of the pressure history at the closed end (thrust wall) without any empirical parameters. By integrating the obtained pressure history at the thrust wall with respect to time, important performance parameters of a PDE were also formulated. The obtained formulas were compared with numerical and experimental results and agreed with them very well. [ABSTRACT FROM AUTHOR]

Post-percutaneous coronary intervention (PCI) fractional flow reserve (FFR) reflects residual atherosclerotic burden and is associated with future events. How much post-PCI FFR can be predicted based on baseline basic information and the clinical relevance have not been investigated. We compiled a multicenter registry of patients undergoing pre- and post-PCI FFR. Machine-learning (ML) algorithms were designed to predict post-PCI FFR levels from baseline demographics, quantitative coronary angiography, and pre-PCI FFR. FFR deviation was defined as actual minus ML-predicted post-PCI FFR levels, and its association with incident target vessel failure (TVF) was evaluated. Median (IQR) pre- and post-PCI FFR values were 0.71 (0.61, 0.77) and 0.88 (0.84, 0.93), respectively. The Spearman correlation coefficient of the actual and predicted post-PCI FFR was 0.54 (95% CI: 0.52, 0.57). FFR deviation was non-linearly associated with incident TVF (HR [95% CI] with Q3 as reference: 1.65 [1.14, 2.39] in Q1, 1.42 [0.98, 2.08] in Q2, 0.81 [0.53, 1.26] in Q4, and 1.04 [0.69, 1.56] in Q5). A model with polynomial function of continuous FFR deviation indicated increasing TVF risk for FFR deviation ≤0 but plateau risk with FFR deviation >0. An ML-based algorithm using baseline data moderately predicted post-PCI FFR. The deviation of post-PCI FFR from the predicted value was associated with higher vessel-oriented event. [Display omitted] • A machine-learning algorithm moderately predicted post-PCI FFR. • Discrepancy of actual and predicted post-PCI FFR was associated with TVF. • No additional benefit would be expected by achieving higher than the predicted FFR. [ABSTRACT FROM AUTHOR]

A high operating frequency of a pulse detonation engine is required to increase the thrust-to-engine weight ratio or thrust density. The semi-valveless pulse detonation cycle (PDC) proposed by Matsuoka et al. (2017) can achieve a high operating frequency exceeding several kilohertz. For achieving a higher operating frequency close to the upper limit of gas dynamics, it is necessary to minimize the process in which the buffer layer is applied to avoid self-ignition of the detonable mixture. Experiments were conducted, and a one-dimensional numerical model was developed to investigate the minimum thickness of the buffer layer and the required duration for the stable PDC operation. Ethylene was used as a fuel and pure oxygen as an oxidizer. The total length of two combustors with an inner diameter of 10 mm was 40 and 80 mm. Therefore, the thickness of the buffer layer of approximately 20 mm was suggested for the stable PDC operation. This result indicated that 10% of the duration of one PDC was required to prevent self-ignition (SI). In the failed PDC, the early and late SI were confirmed. Interestingly, high-frequency PDC operation with a short combustor can suppress late SI and results in a higher success rate with the same thickness of the buffer layer. Furthermore, a stable PDC operation of a 1916 Hz with a combustor with a total length of 40 mm was demonstrated. [ABSTRACT FROM AUTHOR]

Abstract This article reports on an experimental investigation into dynamical behaviours of detonation in non-uniform mixtures, generated from stoichiometric propane–oxygen, oxygen and ethane, with initial temperature and pressure 290 K and 20 kPa, respectively. Composition gradients are parallel to the direction of detonation propagation, with an equivalence ratio (ER) that first decreases from lean values and then increases to rich ones. Composition distributions are characterized according to the depth of the ER sink. Gradients are generated in a 50 × 50-mm2-square cross-section and a 665-mm total length chamber. The mixture components are injected separately in the pre-evacuated chamber in their order of decreasing density through porous plates at the chamber top-end to ensure planar filling of the chamber. Non-uniform distributions are then precisely controlled as a function of time by means of optical oxygen sensors. A Chapman–Jouguet (CJ) detonation is transmitted at the chamber bottom-end from a 3.6-m-long driver tube. Fast pressure transducers, sooted plates and Schlieren visualizations coupled with high-speed cameras are used to characterize the longitudinal velocity, cellular structure and transmission, failure and re-initiation mechanisms of the detonation front. Shallowest ER sinks produce the supercritical transmission mode of the CJ detonation with continuous adaptation of velocity and multicellular structure to local composition. Deepest sinks lead to the subcritical behaviour characterized by sudden detonation failure from shock-flame decoupling when ER decreases, and without detonation re-initiation when ER increases again. Intermediate sink depths generate critical behaviour with detonation re-initiat ion at chamber walls from expanding combustion kernels and reflected transverse Mach waves and then from SWACER retro-active mechanism. An elaboration of the failure criterion used in a previous study is found to well predict conditions for shock-flame decoupling. [ABSTRACT FROM AUTHOR]

A reflective shuttling detention combustor (RSDC) is a two-dimensional combustor with two reflection walls. Unlike a rotating detonation combustor (RDC), an RSDC can visualize the entire area of the combustor via an optical technique. In addition, the RSDC can reproduce the counter-rotating detonation mode in RDC. In present study, CH* luminescence and schlieren image were observed to investigate the dynamics of the RSDC. The reflective wall distance was set to 45 mm (Type L) and 25 mm (Type S). As the results, the wave speed of 1226 ± 64 m / s in the single wave mode in Type S was 76% of that in Type L. It was found that the detonation propagation speed decreased with a reduction in the reflection wall distance. Superimposing the luminescence images on the schlieren images revealed that the mixture was mainly burned by deflagration behind shock wave. In addition, the experimental mixture fill height was in good agreement with model in which the mixture filling process was temporarily stopped by detonation and refilled at a constant speed. Using the maximum fill height obtained by the model, it was found that the detonation mode was in the region of 3 ± 0.6 of the dimensionless quantity (the reflection wall distance divided by the wave number and maximum value of the mixture fill height). [ABSTRACT FROM AUTHOR]

Abstract: This study was a numerical and experimental investigation of low-temperature auto-ignitions behind reflected shock waves in which a shock tube was employed as the experimental system. We used a high-speed video camera and the Schlieren method to visualize the ignition phenomena. Experiments were performed over a temperature range from 549±10 to 1349±11K and a pressure range from 56±2 to 203±13kPa, and a non-diluted stoichiometric acetylene–oxygen mixture was chosen as the combustible gas. We introduced a numerical simulation to help us understand the disturbed temperature distribution behind bifurcated shock waves due to interference between reflected shock waves and the boundary layer developed behind incident shock waves. Additionally, we experimentally observed and evaluated quantitatively a tendency for ignition positions to be located farther from the reflecting wall as the temperature decreased behind reflected shock waves. To focus our attention on the ignition positions, we classified the ignition types behind reflected shock waves as near-wall ignition and far-wall ignition by 4.7mm distance from reflecting wall. The criterion for these ignition types was estimated to be . As a main object in this manuscript, we proposed an ignition model in which local ignition is induced at some distance from reflecting wall based on the numerical simulation and results; the local ignitions at a point distant from the reflecting wall are induced by the temperature rise, with the distance from the reflecting wall, immediately behind concave reflected shock waves due to developing of bifurcated shock waves. We confirmed that there is no discrepancy between the proposed model and experimental results. [Copyright &y& Elsevier]

Abstract: We developed a rotary valve for a pulse detonation engine (PDE), and confirmed its basic characteristics and performance. In a square cross-section combustor, we visualized a multi-shot of a pulse detonation rocket engine (PDRE) cycle at an operation frequency of 160Hz by using a high-speed camera (time resolution: 3.33μs, space resolution: 0.4mm) and a Schlieren method. The propellant filling process and the purge process were confirmed, and each process was modeled. Moreover, we confirmed the processes of detonation wave generation and burned gas blowdown. In addition, we investigated the impact of shortening the passage width of a combustor and negative-time ignition (ignition time is earlier than the end-time of the propellant filling process) on the deflagration-to-detonation transition (DDT) distance and time. The DDT distance did not depend on the passage width of a combustor and decreased under the negative-time ignition condition. With a passage width of 20mm, the DDT distance decreased by 22% under the negative-time ignition condition to a minimum value (76±8mm). The DDT time from spark time reached a minimum value (69±14μs) under the condition of a passage width of 10mm and negative-time ignition. The detonation initiation time and the DDT distance were represented by the time until the flame expanded toward the tube-axis one-dimensionally from ignition (characteristic time). We also carried out thrust measurement using a PDRE system composed of a circular cross-section combustor and the newly developed valve. We obtained a stable time-averaged thrust in a wide range of operation frequency (40–160Hz) and confirmed the increase of specific impulse due to a partial-fill effect. At a maximum operation frequency of 159Hz, we achieved a maximum propellant-based specific impulse of 232s and a maximum time-averaged thrust of 71N. [Copyright &y& Elsevier]

Abstract: The detonation propagation phenomena in curved channels were experimentally studied in order to determine the stable propagation condition. A stoichiometric ethylene–oxygen mixture gas and five types of rectangular-cross-section curved channels with different inner radii of curvature were employed. The detonation waves propagating through the curved channels were visualized using a high-speed video camera. Multi-frame short-time open-shutter photography (MSOP) was developed in the present study to simultaneously observe the front shock shape of the detonation wave and the trajectories of triple points on the detonation wave. The detonation wave became more stable under the conditions of a higher filling pressure of the mixture gas and/or a larger inner radius of curvature of the curved channel. The critical condition under which the propagation mode of the detonation wave transitioned from unstable to stable was having an inner radius of curvature of the curved channel (r i) equivalent to 21–32 times the normal detonation cell width (λ). In the stable propagation mode, the normal detonation velocity (D n) increased with the distance from the inner wall of the curved channel and approached the velocity of the planar detonation propagating through the straight section of the curved channel (D str). The smallest D n was observed on the inner wall and decreased with decreasing r i/λ. The distribution of D n on the detonation wave in the stable mode was approximately formulated. The approximated D n given by the formula agreed well with the experimental results. The front shock shape of the detonation wave could be reconstructed accurately using the formula. The local curvature of the detonation wave (κ) nondimensionalized by λ decreased with increasing distance from the inner wall. The largest λκ was observed on the inner wall and increased with increasing r i/λ. D n/D str decreased with increasing λκ. This nondimensionalized D n–κ relation was nearly independent of r i/λ. [Copyright &y& Elsevier]

Abstract: In the present study, we experimentally and numerically investigated the influence of heat transfer and friction on the performance of a single-shot detonation tube open at one end. Two kinds of specific impulse measurement were carried out with various tube lengths and levels of surface roughness, one by using a ballistic pendulum arrangement and the other by integrating the pressure history measured at the thrust wall. These measurements revealed the degree to which potential impulse can be exploited by the detonation tube after the impulse losses due to various wall loss mechanisms such as heat transfer and friction. The detonation tube obtained 89%, 70%, and 64% of the theoretical ideal impulse for electropolished tubes at a ratio of tube length to diameter (L/D) of 49, 103, and 151, respectively. The impulse losses due to shear stress on the side wall of the detonation tube were found to have a dominant influence on the performance of the detonation tubes of L/D =103 and 151, but the loss was remarkably small for L/D =49 relative to that of the longer tubes. In addition to the experiments, a simplified one-dimensional gas-dynamic model was developed by considering heat transfer and friction as wall loss mechanisms and validated by the experimental results. This simplified model was found to predict the experimental results very well, especially in the range of L/D 103–151. [Copyright &y& Elsevier]

Patients with apical hypertrophic cardiomyopathy (APH) associated with paradoxic jet flow (ie, diastolic flow away from the apex) may gradually develop an apical aneurysm, which often leads to arrhythmia and mural thrombus formation. We observed systolic outward motion of the left ventricular apical myocardium in patients with APH using a magnetic resonance tagging procedure and examined the relationship of the outward motion to echocardiographic and scintigraphic findings and to cardiac events. Systolic displacement of the myocardial tags of the apical region perpendicular to the long axis in the 4-chamber view was recorded in 31 patients with APH. Of these patients, 14 showed no outward movement of tags (group A), and 17 showed outward movement (group B). In group B, apical hypertrophy was more severe (35 ± 7 mm vs. 29 ± 6 mm, p < 0.05), paradoxic jet flow was more frequent(64% vs. 14%, p < 0.05) and the defect score in I-123-beta-methyliodophenylpentadecanoic acid scintigraphy was higher (2.1 ± 0.7 vs. 1.3 ± 0.7, p < 0.01). During a mean follow-up period of 55 months, only 1 patient experienced paroxysmal atrial fibrillation in group A. In group B, 1 patient died suddenly, 1 was admitted to hospital because of congestive heart failure, 2 developed angina pectoris, 2 exhibited non-sustained ventricular tachycardia, and 1 showed multifocal premature ventricular contraction; in these 7 patients the out ward movement was greater than in the 10 patients in Group B who had no cardiac events (1.00 ± 0.59 vs. 0.52 ± 0.40, p < 0.05). Hence, our results show that outward tag displacement is frequently associated with severe apical hypertrophy, paradoxic jet flow, apical ischemia, and cardiac events. The tagging method may be useful in assessing the severity of APH and predicting the occurrence of cardiac events at an early stage. [ABSTRACT FROM AUTHOR]

With the imminent advent of an extremely aged society, there will be an increasing requirement for the prediction, early detection and treatment of cerebral infarction. Involved in the etiological mechanisms of cerebral infarction are a number of complex genetic and environmental factors related to the onset and progression of hypertension and arteriosclerosis. Elucidation of the significance of the various risk factors will require definite identification of phenotypes using large numbers of subjects. The present study was conducted as part of a cohort study with subjects from the general population of a rural community (the Ohasama Study). Blood pressure (BP) patterns were assessed through random home-based and clinical measurements, as well as 24 h ambulatory BP monitoring. Magnetic resonance imaging of the brain was carried out in some subjects in order to detect asymptomatic cerebral infarcts, the maximum intima–media thickness was determined by carotid high-resolution ultrasonography, and cognitive function was assessed using the mini mental state examination. Correlation analysis of these parameters and the candidate hypertensive genotypes was then performed. Significant associations were seen between (i) gene polymorphisms in the renin–angiotensin system and asymptomatic cerebral infarction and the non-dipper pattern of circadian blood pressure variation; and (ii) endothelial nitric oxide synthase (eNOS) gene polymorphism and arterial pressure, lacunar score and cognitive function. An association was seen between the endothelin-1 polymorphism and hypertension, but only in obese subjects. There are interactions between genes and the environment in the etiology of cerebral infarction. [ABSTRACT FROM AUTHOR]

Background: The purpose of the present paper was to determine clinical risk factors for the development of pressure ulcers in bedridden elderly inpatients. Methods: A case-control study was performed for 117 subjects with pressure ulcers (mean age: 80.6 ± 7.2 years) with a 1-year observation period, and 351 age- and sex-matched controls. Factors examined were subitems of the Braden scale; convenient clinical assessment (continence, sitting, turning, oral intake, and sitting up); underlying chronic conditions (stroke and diabetes mellitus); and circulating levels of albumin, total cholesterol, total lymphocyte count, and hemoglobin. Results: Compared to the controls, test cases showed lower scores of the Braden scale and lower levels of circulating factors, and higher incidences of incapability of the subitems of convenient clinical assessment, and of diabetes mellitus (P < 0.20). Three models of multiple logistic regression analysis revealed that decreased serum level of albumin and impaired self-positioning in bed were significant independent risk factors. The relative risk for the development of pressure ulcers after full adjustment in the group with both hypoalbuminemia (< 35 g/L) and incapability of turning over in bed, the group with the former risk alone, and the group with the latter risk alone, was 14.0 (95% confidence interval (CI): 4.2–46.6), 4.9 (1.6–14.9), and 5.9 (1.8–19.0), respectively, compared to subjects without the two risk factors. Moreover, decreased circulating levels of albumin and hemoglobin were associated with aggravation of pressure ulcers. Conclusion: A combined measure of albumin and incapability of self-positioning may serve as a simple but useful index for the risk of pressure ulcers in bedridden elderly inpatients. [ABSTRACT FROM AUTHOR]