Residual stress measurement of YB silicates by Raman Spectroscopy: First-principles and experimental studies

Components of next-generation gas turbines made from lightweight SiC-based ceramics need environmental barrier coatings (EBCs) to protect from water vapor at high temperature because Si-based ceramics vaporize in such environments. Yb silicates Yb2SiO5 and Yb2Si2O7 are promising EBC materials. In EBCs, residual stresses develop during thermal cycling due to mismatch between the thermal expansion coefficients of the silicate and the underlying ceramics, resulting in critical fatigue of the coating structure [1]. Raman microscopy is one method for measuring stress distributions in coating materials and has the potential to be used for diagnosing EBCs. Its suitability for analyzing stress states of Yb silicates has been unknown. In this study, we examine Raman spectra of Yb2SiO5, and Yb2Si2O7 under hydrostatic pressure based on first-principles calculations based on the density functional theory and we also examine the spectra of Yb2Si2O7 under uniaxial compressive stress in experiments using polycrystalline samples. When no external pressures applied, good agreement between calculated and experimental spectra is obtained as shown in Figure 1. The differences in the spectra between the silicates demonstrate the utility of using Raman microscopy to detect compositional changes in Yb-silicate coatings. From the calculations, lattice vibrations associated with a Raman peak are identified as exemplified by the characteristic mode of Si2O7 units in Yb2Si2O7 shown in figure 1(a). Please click Additional Files below to see the full abstract

Stress corrosion cracking of copper in swollen bentonite simulating nuclear waste disposal environment

Stress corrosion cracking (SCC) of pure copper in bentonite clay was examined using a slow strain rate test (SSRT). Bentonite was swollen with pure water or aqueous solutions containing NH₃ of 5 and 10 mM. Thick corrosion films and particulate deposits were formed on the copper surface after the SSRT. Typical tarnish rupture-type SCC occurred on pure copper in swollen bentonite with and without NH₃. The crack propagation rate was enhanced by NH₃. It is confirmed that a thick oxide layer was formed on copper during plastic deformation, resulting in tarnish crack-type SCC. Many particulate deposits observed on the surface were formed due to the rapid dissolution of Cu²⁺ ions to form porous CuO at local deformed sites, regardless of the SCC occurrence

Design of Internal Model Control Based on an Optimal Control for a Servo System

This paper describes a design of internal model control based on an optimal control for a servo system. The control system has the feedback based on the proposed disturbance compensator in the disturbance response. The compensator is designed to become the denominator of the transfer function without a dead time in the disturbance responses. The disturbance response of the proposed method is faster than that of the previous method

Effect of Mix Cropping of Determinate and Indeterminate Lines on Sink-Source Balance in Soybean Grown in Kawatabi Field Center

Poster Session

Development of an appropriate simple suspension method for valganciclovir medication

Background Valganciclovir (VGC) is essential for preventing cytomegalovirus infections after transplants in adult and pediatric patients. In pediatric patients, VGC tablets have to be pulverized so that they can be delivered via nasogastric tubes. The “simple suspension method” is usually used to suspend tablets in hot water in Japan. However, the optimal suspension conditions and metering methods for preparing VGC suspensions using the simple suspension method are unclear. The purpose of this study was to clarify these issues. Methods VGC tablets were suspended in water (initial water temperature: 25 °C or 55 °C) using the simple suspension method. The residual rate of VGC after it had been suspended in hot water was determined using HPLC. In addition, the suspended solution was passed through 6, 8, and 12 Fr. gavage tubes. The VGC concentrations of suspensions produced using different preparation methods were also determined using HPLC. Results Cracking the surfaces of VGC tablets and suspending them in water at an initial temperature of 55 °C was effective at dissolving the tablets. The VGC concentration of the suspension remained stable for at least 80 min. Furthermore, the VGC concentration remained stable for 48 h during cold dark storage. Cracking the surfaces of VGC tablets could be a more effective metering method than preparing powder from VGC tablets. In addition, little VGC remained in 6, 8, or 12 Fr. gavage tubes after VGC solution was passed through them. Conclusion The amount of VGC should be measured carefully when preparing VGC solutions using the simple suspension method

Interrelationships Between Serum Levels of Procalcitonin and Inflammatory Markers in Patients Who Visited a General Medicine Department

Various laboratory markers of inflammation are utilized in general practice, but their clinical diagnostic significance is often ambiguous. In the present study, we determined the clinical significance of the examination of serum levels of procalcitonin (PCT) by comparing the PCT levels with the levels of other inflammatory markers, based on a retrospective review of 332 PCT-positive patients, including cases of bacterial infection (20.5%), non-specific inflammation (20.8%), neoplasm (9.9%), connective tissue diseases (8.4%), and non-bacterial infection (7.2%), were analyzed. The serum PCT level was highest in the bacterial infection group (1.94 ng/ml) followed by the non-specific inflammatory group (0.58 ng/ml) and neoplastic diseases group (0.34 ng/ml). The serum PCT level was positively correlated with serum levels of C-reactive protein (rho=0.62), soluble interleukin-2 receptor (sIL-2R; rho=0.69), and ferritin, the plasma level of D-dimer, and white blood cell count, and negatively correlated with the serum albumin level (rho=−0.52), hemoglobin concentration, and platelet count. The serum PCT level showed a stronger positive correlation with the serum sIL-2R level than the other biomarkers. The results suggest that an increased PCT level may indicate not only an infectious state but also a non-bacterial inflammatory condition in the diagnostic process in general practice

Clinical Application of the Ratio of Serum Bone Isoform to Total Alkaline Phosphatase in General Practice

Alkaline phosphatase (ALP) is an enzyme that is expressed in a variety of tissues. Among the isoforms of ALP, bone-specific alkaline phosphatase (BAP) is used as a marker for evaluating bone metabolism. We investigated the clinical usefulness of the ratio of serum BAP to total ALP for the diagnosis of various disorders in general practice. We retrospectively analyzed the cases of 107 Japanese patients whose serum BAP levels were exam-ined, focusing on clinical characteristics. We observed that the BAP/ALP ratios of the patients with fever and those with inflammatory diseases were significantly lower than the ratios of other patient groups. The BAP/ALP ratios of the patients with osteoporosis and those with metabolic bone diseases were higher than those of the patients with other conditions. The BAP/ALP ratio was found to be negatively correlated with age, a cor-relation that has not been found in other ethnicities. The serum BAP/ALP ratio was inversely correlated with serum CRP levels but was positively correlated with serum albumin levels and hemoglobin concentrations. Collectively, our results suggest that the BAP/ALP ratio could be a useful predictor for important geriatric con-ditions seen in general practice

Relationship between patients' characteristics and efficacy of calcimimetics for primary hyperparathyroidism in the elderly

Calcimimetic treatment has been reported to be effective for primary hyperparathyroidism (PHPT). Nine elderly PH PT patients who had been treated with calcimimetics were retrospectively analyzed. It was found that calcimimetics can reduce elevated serum calcium levels in elderly PHPT patients with low femoral DEXA %YAM and low urinary cAMP levels

Clinical Relevance of Serum Prolactin Levels to Inflammatory Reaction in Male Patients

To clarify the relevance of prolactin (PRL) to clinical parameters in patients who visited our general medicine department, medical records of 353 patients in whom serum PRL levels were measured during the period from 2016 to 2018 were retrospectively reviewed. Data for 140 patients (M/F: 42/98) were analyzed after excluding patients lacking detailed records and patients taking dopaminergic agents. Median serum PRL levels were significantly lower in males than females: 6.5 ng/ml (IQR: 4.2-10.3) versus 8.1 ng/ml (5.9-12.9), respectively. Pain and general fatigue were the major symptoms at the first visit, and past histories of hypertension and dyslipidemia were frequent. Male patients with relatively high PRL levels (≥ 10 ng/ml) had significantly lower levels of serum albumin and significantly higher levels of serum LDH than those with low PRL (< 10 ng/ml). There were significant correlations of male PRL level with the erythrocyte sedimentation rate (R=0.62), serum LDH level (R=0.39) and serum albumin level (R=−0.52), while the level of serum CRP (R=0.33) showed an insignificant but weak positive correlation with PRL level. Collectively, these results show that PRL levels had gender-specific relevance to various clinical factors, with PRL levels in males being significantly related to inflammatory status