Search

Objective Computed tomography (CT) can be used for visualizing acute intracerebral hemorrhages (ICHs) as distinct hyperdense areas and cerebral edema as perihematomal low-density areas (LDAs). We observed a perihematomal LDA on CT, which appeared to be part of a hemorrhage on magnetic resonance imaging (MRI) in acute ICH. We named this "CT perihematomal rim" and evaluated its characteristics and clinical significance. Methods We stratified patients with acute ICH according to the presence or absence of a CT perihematomal rim and then compared their radiologic findings. Logistic regression analyses were performed to assess whether the CT findings can predict the presence of a CT perihematomal rim. Patients Patients within 24 hours of ICH onset who were admitted between September 1, 2014, and October 31, 2018, were registered. Results Overall, 139 patients (91 men; mean age, 66 years) were investigated. CT perihematomal rims were observed in 40 patients (29%). ICH volumes on CT were 30% smaller than those on MRI in patients with CT perihematomal rims. On a multivariate analysis, the presence of a CT perihematomal rim was independently associated with the maximum diameter of the perihematomal LDA. According to a receiver operating characteristic analysis, the maximum LDA diameter threshold was 7.5 mm (sensitivity, 85%; specificity, 83%). Conclusion CT perihematomal rims were observed in 29% of the patients with acute ICH. A perihematomal LDA (>7.5 mm) in acute ICH cases should be considered a CT perihematomal rim. Clinicians should be aware that the ICH volume on CT may be underestimated by 30%.

Fucosylation is an important type of glycosylation involved in cancer, and fucosylated proteins could be employed as cancer biomarkers. Previously, we reported that fucosylated N-glycans on haptoglobin in the sera of patients with pancreatic cancer were increased by lectin-ELISA and mass spectrometry analyses. However, an increase in fucosylated haptoglobin has been reported in various types of cancer. To ascertain if characteristic fucosylation is observed in each cancer type, we undertook site-specific analyses of N-glycans on haptoglobin in the sera of patients with five types of operable gastroenterological cancer (esophageal, gastric, colon, gallbladder, pancreatic), a non-gastroenterological cancer (prostate cancer) and normal controls using ODS column LC-ESI MS. Haptoglobin has four potential glycosylation sites (Asn184, Asn207, Asn211, Asn241). In all cancer samples, monofucosylated N-glycans were significantly increased at all glycosylation sites. Moreover, difucosylated N-glycans were detected at Asn 184, Asn207 and Asn241 only in cancer samples. Remarkable differences in N-glycan structure among cancer types were not observed. We next analyzed N-glycan alditols released from haptoglobin using graphitized carbon column LC-ESI MS to identify the linkage of fucosylation. Lewis-type and core-type fucosylated N-glycans were increased in gastroenterological cancer samples, but only core-type fucosylated N-glycan was relatively increased in prostate cancer samples. In metastatic prostate cancer, Lewis-type fucosylated N-glycan was also increased. These data suggest that the original tissue/cell producing fucosylated haptoglobin is different in each cancer type and linkage of fucosylation might be a clue of primary lesion, thereby enabling a differential diagnosis between gastroenterological cancers and non-gastroenterological cancers.

The main steam stop valve (MSSV) is installed in the main steam line in thermal and nuclear power plants. The MSSV is a safety valve that instantaneously shuts off the steam flowing into the steam turbine in an emergency. However, as high-speed steam flow goes through the MSSV during even the rated operation, acoustic sound or noise is generated in the MSSV. Moreover, there is a possibility that flow-induced acoustic resonance occurs in the MSSV. Flow-induced acoustic resonance must be suppressed to decrease the sound noise. Reducing the pressure loss of the MSSV is also an important issue that cannot be neglected with respect to the plant thermal efficiency. Therefore, we have developed the MSSV which can suppress the flow-induced acoustic resonance and its pressure loss. To develop this MSSV, we conducted scale air tests and computational fluid dynamics (CFD) analyses that are described in this paper. Mach and Strouhal number of the test conditions were the same as those of an actual plant. Reynolds number was sufficiently large to obtain the developed turbulent flow. An unsteady compressible CFD analysis was also conducted using large eddy simulation as a turbulence model. We developed new tilted triangular tabs and installed them in the MSSV to suppress the intense vortex generation and pressure loss. As a result, the sound noise due to the flow-induced acoustic resonance was completely attenuated and pressure loss was reduced compared to the case using the current tilted tabs. CFD results also showed that the tilted triangular tabs could suppress the generation of intense vortexes and the flow-induced acoustic resonance.

Nuclear power plants are designed to prevent the damage of safety installations and human safety due to the jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics analysis (CFD). The flashing steam jet was evaluated in this study. Shapes of flashing jet were obtained by CFD calculations, and we have found that the affected region was wider than usual steam jet flow and strongly depends on the nozzle exit flow conditions. This is thought as the different tendency from established standards.

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.

Some problems due to flow-induced vibrations related to closed side branch pipes have been observed in thermal and nuclear power plants. Fluctuating pressure generated in the main pipes was unusual...

Background Fucosylated haptoglobin (Fuc-Hpt) is a novel cancer biomarker that increases in various pathological conditions. We previously established a Fuc-Hpt lectin–antibody assay using Aleuria aurantia lectin (AAL), and applied this to diagnose several diseases, including various cancers. AAL recognizes both α1-3/1-4 and α1-6 fucosylation on N/O-linked glycans. These fucosylation types differ in biological function, and in regulation by different fucosyltransferases. Recently, we identified a novel lectin, Pholiota squarrosa lectin (PhoSL), which specifically recognizes α1-6 fucosylation (core-fucosylation). Methods We developed a lectin–antibody ELISA kit using PhoSL to determine core-Fuc-Hpt levels in sera from colorectal or pancreatic cancer patients. Results Serum levels of AAL-reactive Hpt are higher in pancreatic cancer patients, whereas those of PhoSL-reactive Hpt are higher in colorectal cancer patients. Mass spectrometry analyses of Hpt fucosylation levels were consistent with lectin–antibody ELISA results. Hpt-transfected colorectal cancer cell lines produced significant amounts of core-Fuc-Hpt, suggesting that colorectal cancer tissues produce core-Fuc-Hpt. Conclusions These differences in Fuc-Hpt patterns might depend on cancer cells and the surrounding cells, which produce Hpt.

Flow-induced acoustic resonances in piping with closed side branches or T-junctions are one of the causes of severe structural vibrations, which sometimes cause fatigue damage to piping and components in a power plant and many engineering applications. In this paper, on the basis of the results of steam flow experiments and calculations, the effects of the liquid phase on the flow-induced acoustic resonance at closed side branches in the steam flow piping of BWRs are described, and some suggestions for the steam piping design of BWRs are also given. The liquid phase in a steam flow forms droplets or liquid film, which may affect the amplitude, frequency and critical Strouhal number of the resonance. From the results of wet steam experiments and CFD calculations, we have found that in some cases the wetness of the steam flow may decrease the resonant amplitude and change the frequency owing to the interaction of the vortex generation or damping by the existence of the liquid film and droplets. Therefore, for the wet steam piping design of BWR, some suggestions for taking these effects into consideration, under actual BWR steam conditions are described.

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.

Many experimental studies related to the flow-induced acoustic resonance closed side branches have been reported. However, few studies have reported on the effects of air/steam flow and steam wetness dependence on fluctuating pressure amplitude. Therefore, we investigated the effect of air/steam flow and steam wetness dependence on fluctuating pressure amplitude by conducting a high temperature and high pressure tests at the Hitachi Utility Steam Test Leading Facility (HUSTLE). The test section consisted of a main pipe and a side branch. The side branch was mounted on the long straight main pipe. Fluctuating pressures at the end face of the side branches were measured. The following two results were obtained; the first is that the air/steam flow had little effect on the fluctuating pressure amplitude normalized by dynamic pressure and frequency normalized by the resonance frequency; the second is that under the acoustic resonance (St = 0.41) and non-resonance (St = 0.55) conditions, fluctuating pressure a...

The main steam stop valve (MSV) in thermal or nuclear power plants is liable to undergo excitation by sound having a specific frequency. The purposes of this article are to clarify the mechanism of the sound generation in the MSV using numerical analysis and to propose a suppression method for the sound generation. The analysis results were validated experimentally using a 1/5-scale model of a typical MSV. The analysis results showed good agreement with the experimental data. From the analysis results, it was clarified that the sound of the MSV was generated by the hole-tone in the opening and the acoustic resonance in the vertical direction of the MSV. A method was proposed to install triangular or slanted tabs at the inlet seat of the MSV in order to prevent formation of vortex rings in the opening which leads to the hole-tone. Effects of the proposed method were tested experimentally. Eight triangular tabs having a height of 15% of the inner diameter in the seat reduced the peak value of the sound pressure by 60%. Eight slanted tabs having a height of 7.5% of the inner diameter in the seat suppressed generation of the hole-tone in the MSV. These results showed that the slanted tabs are effective in suppression of the hole-tone compared with the triangular tabs.

Nuclear power plants are designed to avoid damage to their safety installations because of jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics (CFD) analysis. The steam jet tests obtained using particle image velocimetry (PIV) were conducted in order to verify the CFD analysis. Spread of steam jets could be visualized and the shapes of the steam jets obtained by analysis were almost the same as those by tests. The spread angle of free jet was investigated using CFD analysis. We also measured jet fluid force when a cylindrical structure was installed downstream from the jet nozzle. Steam jet fluid force obtained by analysis was almost the same as that by tests. We judged the CFD analysis to be applicable to evaluation of jet fluid force generated from ruptured pipes.

Nuclear power plants are designed to prevent the damage of safety installations and human safety due to the jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics analysis (CFD). The steam jet tests using particle image velocimetry were conducted in order to verify the CFD methods. Spread of steam jet could be visualized. Shapes of steam jet obtained by CFD were almost the same as those by tests. The spread angle of free jet were investigated using CFD, and we have found that the spread angle strongly depends on the inlet pressure. This is thought as the different tendency from Established Standards.

Nuclear power plants are designed to avoid damage to their safety installations because of jet impingement when a pipe is ruptured. We have investigated the evaluation method for the design basis of protection of plants against effects of a postulated pipe rupture using the established standard of the American National Standards Institute (ANSI). The steam jet tests using particle image velocimetry and computational fluid dynamics (CFD) analysis were conducted for this verification. Spread angle of steam jet could be visualized. The jet spread angles were lower than 10 deg which was described in the ANSI standard. The ANSI standard was conservative for evaluations of the jet impact region compared to actual test and CFD results. However, it is desirable to use the conservative angle for evaluation of the jet fluid force. We could adequately evaluate the conservative jet fluid forces by the ANSI standard considering the spread suppression region and jet spread angle of 6 deg.

In the case of flow-induced acoustic resonance with multiple side branches, the pulsation amplitude may be significantly enhanced compared to the case of a single branch. However, few studies have been presented on the effects of the distance between tandem branches or side branches on fluctuating pressure amplitude. In this study, we carried out several air flow experiments at ordinary temperatures and pressures to investigate the effect of the geometrical and flow parameters on the general acoustic resonance. In the case of a single branch, the dimensionless acoustic pressure amplitude at resonance increases as the cross-sectional ratio of the main and branch pipes is decreased. This is attributed to the acoustic radiation loss from the branch pipe to the main pipe increasing at higher values of the cross-sectional ratio. In the case of coaxial branches, the pressure amplitude shows a counter tendency to that in the case of a single branch. This is because the two branches strongly couple and form a standing wave with negligible radiation losses. In the case of tandem branches, peak pressure and frequency change cyclically as the distance between tandem branches changes.

The boiling water reactors (BWRs) have steam dryer in the upper part of the pressure vessel to remove moisture from the steam. The steam dryer in the Quad Cities Unit 2 nuclear power plant was dama...

The boiling water reactor (BWR-3) steam dryer in the Quad Cities (QC) Unit 2 Nuclear Power Plant was damaged by high-cycle fatigue due to acoustic-induced vibration. The cause of the dryer failure was considered as flow-induced acoustic resonance at the stub pipes of the safety relief valve (SRV) in the main steam lines (MSLs). The acoustic resonance was considered to be generated by the interaction between the sound field and an unstable shear layer across the closed side branches of SRVs. We have started a research program on BWR steam dryers to develop methods of evaluating the loading. Moreover, it is necessary to evaluate the dryer integrity of BWR-5 plants, which are the main type of BWR in Japan. In the present study, we conducted 1/10-scale BWR model tests and analysis to investigate the flowinduced acoustic resonance and acoustic characteristics in MSLs. The test apparatus consisted of a steam dryer, a steam dome, and 4 MSLs with 20 SRV stub pipes. Computational fluid dynamics (CFD) analysis was ...

The lattice Boltzmann method (LBM) has been widely used for the simulations of the incompressible Navier–Stokes (NS) equations. The finite difference Boltzmann method (FDBM) in which the discrete-velocity Boltzmann equation is solved instead of the lattice Boltzmann equation has also been applied as an alternative method for simulating the incompressible flows. The particle velocities of the FDBM can be selected independently from the lattice configuration. In this paper, taking account of this advantage, we present the discrete velocity Boltzmann equation that has a minimum set of the particle velocities with the lattice Bharnagar–Gross–Krook (BGK) model for the three-dimensional incompressible NS equations. To recover incompressible NS equations, tensors of the particle velocities have to be isotropic up to the fifth rank. Thus, we propose to apply the icosahedral vectors that have 13 degrees of freedom to the particle velocity distributions. Validity of the proposed model (D3Q13BGK) is confirmed by numerical simulations of the shear-wave decay problem and the Taylor–Green vortex problem. With respect to numerical accuracy, computational efficiency and numerical stability, we compare the proposed model with the conventional lattice BGK models (D3Q15, D3Q19 and D3Q27) and the multiple-relaxation-time (MRT) model (D3Q13MRT) that has the same degrees of freedom as our proposal. The comparisons show that the compressibility error of the proposed model is approximately double that of the conventional lattice BGK models, but the computational efficiency of the proposed model is superior to that of the others. The linear stability of the proposed model is also superior to that of the lattice BGK models. However, in non-linear simulations, the proposed model tends to be less stable than the others.

A percutaneous transvascular angioplasty (PTA) is performed to relieve failed vascular access for hemodialysis. Angiography using non-ionic iodinated contrast media is the imaging modality of choice for performing PTA. However, the use of iodinated contrast media is contraindicated for patients with a history of iodine allergy. Since 1920, carbon dioxide (CO(2)) has been used as a safe contrast medium in various studies. In CO(2) shunt angiography for hemodialysis, visualization of the vascular structures was often suboptimal due to shunt-specific conditions, such as rapid flow and narrow diameter of the vessels. In the present report, we attempted an improvement of the visualization by injection of CO(2) bubbles in view of the properties of CO(2) (floating and low viscosity). The results indicated that the CO(2) bubbles angiography clearly demonstrated the narrow vessels and stenotic portions that were not visualized by conventional CO(2) angiography. In addition, the required volume of CO(2) could be reduced in comparison with previous studies in the literature. Therefore, the method seemed to be effective in reducing exposure and preventing complication by CO(2). Thus, CO(2) bubbles angiography may be useful for shunt angiography and sequential angioplasty when experiencing shunt problems.

石川県済生会金沢病院放射線部, 金沢大学医薬保健研究域保健学系, Objective:: Preoperative evaluation of bronchovascular structures is useful for prevention of accidents in pulmonary lobectomy. The purpose of this study was to examine the frequency and multidetector computed tomographic (CT) appearances of bronchovascular anomalies between the right middle and lower lobes. Methods:: A total of 1116 consecutive chest CT examinations were analyzed in the present study. On display, the bronchovascular anomalies between the right middle and lower lobes were searched. When anomalous structures were observed, 3-dimensional images were reconstructed. Results:: Sixty-seven cases (6.0%) with anomalous findings were observed. In 20 cases (1.79%), the right middle lobe bronchus and artery supplied the lower lobe, whereas the lower lobe artery supplied the right middle lobe in 46 cases (4.12%). In 1 case (0.09%), the 2 patterns previously mentioned were observed concomitantly. Conclusions:: Anomalous bronchovascular structures between the right middle and lower lobes were identified by a multidetector CT with an incidence of 6.0%. Knowledge of the frequency and CT features is useful for preoperative CT evaluation. © 2009 Lippincott Williams & Wilkins.

In this study of the phosphor utilizing a scallop shell, it was researched that the luminescence center was estimated from the chemical composition of the shell for the final purpose of the improvement of the luminescence property. The luminescence centers were estimated to be Cu and Mn from the experiment result and literature investigation. Furthermore, these concentrations were small by more than two orders in comparison with the commercially available phosphors. Therefore, improvement of the luminescence property can be expected by doping Cu and Mn to the shell and to investigate the relationship between these concentrations and the luminescence property to find the optimum concentration.

In this paper, a novel arc-shape FBG (Fiber Bragg Grating) load sensor is developed with a pair of FBGs embedded symmetrically in an elastic bending beam. The FBG pair is produced with peak wavelength separation of about 0.4 nm. The FBG with shorter wavelength is located above the neutral layer and another with longer wavelength below the neutral layer. As a result, the two peak wavelengths of the FBG pair move apart with lateral force applied but move together in the same direction when surrounding temperature varies, both in a linear manner. A very low temperature-dependency of only 0.04 pm/°C across the temperature range from 35°C to 82°C has been achieved, which makes it suitable for dynamic lateral force measurement even when the environmental temperature varies. Due to the fact that the sensor module consists of only the grating fiber with two FBGs and some elastic material, which are purely passive components, hence, the temperature effect of this sensor can be self-compensated without a need of an...

Nanocrystalline iron powders with grain size of 13nm were prepared by ball-milling. The nano-structured iron powders were consolidated into discs with a diameter of 30 or 50 mm by Spark Plasma Sintering at 550°C under pressures between 80 to 220 MPa. The average grain size of the consolidated discs is about 80 nm. It does not depend on the sintering time at constant pressure. The Vickers hardness of the superfine grained iron sintered for 600 s with 220 MPa is 470 Hv. The value is plotted on the linearly extrapolated line of the Hall-Petch relationship obtained by Malow and Koch in the study on the grain size smaller than 40 nm.

Previous plant measurements and scale model tests have demonstrated that intense fluctuating pressure acted on the steam dryer in boiling water reactors (BWRs) at higher velocity flows than in normal operation. The cause of the dryer loading was considered as flow-induced acoustic resonance at the stub pipes of safety relief valves (SRVs) in the main steam lines (MSLs). Acoustic resonance was considered to be generated by the interaction between the sound field and the unstable shear layer across the opening of the side branches of the SRV stub pipes. Some air scale tests have been conducted and they are useful for evaluation of occurrence of acoustic resonance in SRV stub pipes and characteristics of fluctuating pressure in MSLs. However, it is possible that differences in pressure conditions and fluid properties may cause the dryer loading to be underestimated. In the present study, we conducted scale tests under actual steam conditions to evaluate the scale model test methods for BWR dryer loading estimation. The test apparatus consisted of a steam dryer, steam dome and 4 MSLs with 20 SRV stub pipes. We demonstrated that acoustic resonance occurred in the SRV stub pipes and the fluctuating pressure which propagated from the SRVs to the dryer caused fluctuating stress on the steam dryer at the SRV resonance frequency. Acoustic resonance started when Strouhal number decreased below 0.6 in both the scale model air and steam tests. The onset of resonance due to the single vortex mode was not influenced by pressure conditions and fluid properties. The increase of fluctuating pressure due to the double vortex mode which occurred at Strouhal number values from 0.8 to 0.9 could be clearly seen in the scale model steam tests unlike in the air tests. The results showed that the self-excited acoustic resonance was affected by the static pressure and fluid properties for the scale model air tests. However, no significant influence from steam pressure was seen at pressure higher than 3 MPa. Normalized fluctuating pressure was almost the same regardless of pressure. We verified that normalization by dynamic pressure in the main pipe was a reasonable approach for evaluation of fluctuating pressure in the SRV stub pipes. Increase of fluctuating pressure due to the double vortex mode was clearly distinguished in SRV stub pipes but not strong in the MSL pipes and had insignificant impact on the dryer loading.

This paper introduces nuclear power plant issues described in International Atomic Energy Agency (IAEA) technical guidelines on fluid-structure interactions (FSIs). The occurrence of FSIs has been recognized for a long time in industry. It is sometimes difficult to predict the FSI phenomena accurately, however, and FSI vibration and water hammer are concerns for structural design or trouble shooting. There have been many problems caused by FSIs in nuclear power plants. In order to avoid FSI problems for newly designed components, it is important to learn from past FSI events that have occurred at actual plants. Four major types of FSI events that have been publicly disclosed are introduced here and the importance of evaluating reactor internals with respect to flow-induced vibration is noted, if the designs of the reactor internals are for prototypes or the operating conditions are changed. The especially significant internals that are susceptible to flow-induced vibration based on past experience are introduced.

In nuclear power plants, fluid structure interactions (FSI) occurring in component systems can cause excessive forces or stresses to the structures resulting in mechanical damages that may eventually threaten the structural integrity. FSI in the guidelines includes flow-induced vibration, water hammer, and pipewhip. It can also include movement, deformation, or fracture of equipments by tsunami etc. They can be issues of design and maintenance. Authors cannot find complete guidelines to correspond to the FSI phenomena which can be important in the design and maintenance of nuclear power plants. Based on the background, International Atomic Energy Agency (IAEA) has drafted guidelines on FSI. This paper summarizes general description of FSI as well as design and maintenance against FSI.Copyright © 2014 by ASME

Plants have many tee pipes where a hot fluid and cold fluid flow into each other and mix. The mixing of hot and cold water can cause a fluid temperature fluctuation which leads to the temperature flutctuation of the inner pipe wall, so characteristics of this flucuation in the mixing tee pipe were investigated through experiments. This paper shows the three mixing flow patterns in the tee pipe, i. e. stratified flow, turned jet and wall jet, the location of the maximum fluid temperature fluctuation and fluid temperature fluctuation characteristics downstream from the tee pipe. The experiments showed that characteristics of the fluid temperature fluctuation were largely related to the flow pattern in the tee pipe. The flow pattern of the turned flow in the tee pipe could suppress the fluid temperature fluctuation.

Ti–6Al–2Sn–4Zr–2Mo alloy matrix composites reinforced with various volume fractions of TiB particles were fabricated using the blended elemental powder method in the present study. The static and dynamic fracture toughness tests were carried out on the composites at room temperature in order to understand the fracture mechanism. The dynamic fracture toughness value is fairly smaller than the static fracture toughness value. The ratio of dynamic fracture toughness value to static fracture toughness value increases with increasing the volume fraction of TiB particles. The fracture toughness value increases with increasing the degree of crack deflection which is greater under static conditions than under dynamic conditions. The fraction of TiB particles on the fracture surface is greater in the specimen with greater volume fraction of TiB particles, and is greater under dynamic conditions than under static conditions. Since the debonding of TiB particles from the matrix and shearing of TiB particles occurs easily, the fracture toughness value of composites decreases with increasing the volume fraction of TiB particles.

The extraordinarily large expansion observed during sintering of bodies from incinerated ash of sewage sludge was investigated in connection with chemical states of iron in the bodies. The ash was pressed into a rectangular body under 100MPa, and the body was fired at 1000°C for 3h in flowing Ar-O2(PO2: 0.1-1.0kPa) atmosphere. The bulk density of the bodies fired in various atmospheres decreased with a decrease in oxygen partial pressure. The formation of porous black core accompanied by extraordinary expansion was observed in the bodies fired at PO2=0.1-0.7kPa. Reflectance spectra and the ratio of Fe2+ to total Fe measured by chemical analysis indicated that iron oxide in the black core was in the form of FeO or Fe3O4. The evolution rate of CO2 during heating of the body was measured by using a quadruple mass spectrometer. In the case of PO2=0.5kPa, the evolution rate of CO2 at 1000°C was higher than the rate of O2 supply through the atmospheric gas flow. The fact indicated that the ferric oxide was reduced to ferrous oxide by the residual carbon and the evolution of CO2 occurred inside the body under lower oxygen partial pressure.

Background: Bile duct injury is one of the serious surgical complications of laparoscopic cholecystectomy (LC). Clear biliary tract imaging to detect the anomaly of the bile ducts before operation is thought to be useful to prevent this complication. The objective of this study was to investigate the preoperative feasibility of using multi-slice computed tomography scanning after drip infusion cholangiography–computed tomography (DIC-CT) for LC. Methods: Laparoscopic cholecystectomies were carried out in 33 patients and DIC-CT and magnetic resonance cholangiography (MRC) were also carried out in all of these patients. We evaluated the recognition of the junction of the cystic duct and detection of anomalies of the extrahepatic bile ducts using the latter two methods. Results: In 33 patients, DIC-CT showed the junction of the cystic duct in 31 (94%) and MRC in 25 (76%) patients, respectively. Anomalies of the extrahepatic bile ducts or the cystic duct were detected in four (12%) patients by DIC-CT, but MRC could show only one of these lesions. There were no major adverse reactions in either examination. Conclusion: DIC-CT is an efficacious preoperative technique as compared with MRC for the biliary tract imaging. DIC-CT may be of benefit for both patients scheduled to undergo LC and their surgeons.

Brick making from 100 percent of incinerated sewage sludge ash is developed. There are already 8 full scale plants in Japan. All of them employ high pressure molding of incinerated sewage sludge ash and firing at about 1000°C. The end products are widely accepted for public works such as flooring of plazas or pedestrian walk ways. Early in the history of the development, overall quality of the sewage brick was not competitive. They were subject to get moss growth on the surface because of its high moisture content, or whitening because of leaching of Calcium Carbonate. The problems were solved by increasing the temperature of the firing process and by chemical coating. The manufacturing cost of one sewage brick is around two dollars and the retail price is one dollar.

Characterization of black core in a brick body obtained by sintering the incinerated ash of sewage sludge was conducted to clarify its formation mechanism. The ash was pressed into a rectangular body under 100MPa and the body was fired at 1000°C. Under some firing conditions, the formation of porous black core accompanied by extraordinary expansion occurred in the brick body. TG and ESR analyses revealed that iron oxide in the black core was mainly in the form of FeO. The mass-spectrometric analysis of gases released during heating the ash in an oxidizing atmosphere revealed that CO2 was the only gaseous product and it had to be brought about from the residual carbon. These results indicate that Fe2O3 in the ash was reduced to FeO by this carbon. Furthermore, it was assumed that cavities in the body were formed due to the blockade of CO and CO2, formed at the reduction of Fe2O3 to FeO, by the densely sintered surface.

Thermal and nuclear power plants have many T-tubes where a hot fluid and a cold fluid flow into each other and mix. An optimally designed T-tube can be used to shorten mixing time which can lead to more compact plants. We have experimentally investigated the mixing characteristics of hot and cold fluid flows into a T-tube. This paper shows the mixing distance, an analogy between thermal and mass diffusion, and the optimum condition for rapid mixing. We propose a T-junction arrangement using a downstream bent tube as a mixing promoter. The experiments so far clarify that the bent tube can best enhance mixing when the branch tube in the T comes from the opposite direction to the bend. For example, at the velocity ratio u/U=1. the bent tube can reduce the mixing distance from 35D to 8D and still achieve sufficient mixing.

Anisotropic (uniaxial) pressure effects on T c were, for the first time, measured in electron-doped high-temperature superconductor Nd 1.84 Ce 0.16 CuO 4 . In contrast to a report that the isotropic-pressure effect is anomalously absent up to several GPa in electron-doped high- T c superconductors, a reduction of T c is observed under anisotropic pressure along the c -axis within P ∥ c = 0.5 GPa . It is also found that the effect shows a non-linear dependence on P ∥ c , i.e., T c -suppression is enhanced above ∼ 0.3 GPa .

It has been demonstrated that intense fluctuating pressures acted on the steam dryer in a boiling water reactor (BWR) at higher velocity flows than in normal operation through actual BWR plant tests [1] and scale model air tests [2]. The cause of the dryer loading was considered as flow-induced acoustic resonance at the stub pipes of safety relief valves (SRVs) in the main steam lines (MSLs). Acoustic resonance was considered to be generated by interaction between the sound field and an unstable shear layer across the closed side branches of the SRV stub pipes. We have started a research program on BWR dryers to develop their loading evaluation methods. Some air scale tests were conducted and those are useful for evaluation of occurrence of acoustic resonance in SRV stub pipes and characteristics of fluctuating pressure in MSLs. However, it is a possibility that differences in pressure conditions and fluid proprieties caused the dryer loading to be underestimated. In the present study, we conducted scale tests under actual steam conditions to evaluate the scale model test methods for BWR dryer loading estimation. The Hitachi Utility Steam Test Leading facility (HUSTLE) was used for the scale model steam tests of MSLs and a steam dryer. Steam which was at the same pressure and temperature conditions as an actual BWR was used in the tests. The test apparatus consisted of the steam dryer, steam dome and 4 MSLs with 20 SRV stub pipes. We demonstrated that acoustic resonance occurred in the SRV stub pipes and fluctuating pressure which propagated from the SRVs to the dryer caused fluctuating stress on the steam dryer at the SRV resonance frequency. The increasing of fluctuating pressure due to the double vortex mode which occurred at a Strouhal number (St) from 0.8 to 0.9 could be clearly seen in the scale model steam tests unlike in the air tests. It was possible that self excited acoustic resonance was affected by the low pressure conditions and different fluid proprieties for the scale model air tests. However, no significant influence from steam pressure was seen at more than 3MPa. Normalized fluctuating pressure was almost the same regardless of pressure. We verified that normalization by dynamic pressure in the main pipe was a reasonable approach for evaluation of fluctuating pressure in the SRV stub pipes. Increasing of fluctuating pressure due to the double vortex mode was clearly distinguished for SRV stub pipes but became smaller for MS pipes and had insignificant impact on the dryer loading.