Analysis of aerodynamic noise generated from inclined circular cylinder

IntroductionThe public attention to environment' has beenincreased in these days, and noise reduction of ventilationfan is extremely needed more than ever. We must reducethe generated noise and control the resources of thediscordant one. Recently, aerodynndc noise problems,e.g. wind-pass sound from high-speed mobiles, noisefrom cooling fan, are increased rapidly. Manyexperimental studies have been reported tO contfol thegenerated noise, and numerical prediction of aerodyntricsound (CAA; Comp…     

Enhanced Grain Refinement Through Deformation Induced α Precipitation in Hot Working of α + β Titanium Alloy

This study reports a novel forging process to fabricate bulk fine‐grained (grain size ≈ 1 µm) Ti–6Al–4V alloy, in which temperatures near the β transus (T_β) and strain rates around 0.15 s^?1 are used for the deformation. The formation of fine‐grained microstructure is mainly result from the deformation‐induced precipitation of α grains from the β matrix.     

Demonstration of loss reduction effect of 66 kV‐classed 30 MVA three phase hybrid‐core transformer by trial manufacture

To realize larger‐capacity “Hybrid‐core transformer: HBT”, this research has assembled a 30‐MVA three‐phase trial HBT and evaluated the loss performances. The hybrid‐core consisting of the wound amorphous‐ and the stacked silicon steel‐cores, is expected having advantages of lower iron loss of the iron‐based amorphous material and the higher mechanical strength and saturation magnetic flux density of the silicon steels simultaneously. Three‐dimensional finite‐element method analysis revealed that the silicon steel core prevented over‐saturation of the amorphous core. The hybrid configuration enabled the design to have an approximately 10% higher magnetic flux density than configurations with only an amorphous core. We then assembled a prototype 30‐MVA three‐phase HBT designed on the basis of our investigation results. Operation tests demonstrated that the HBT has 62%‐reduced iron loss and 0.10%‐higher 50%‐loaded power efficiency from the conventional silicon steel core transformer.     

Development of a Method for Scaffold-Free Elastic Cartilage Creation

Microtia is a congenital aplasia of the auricular cartilage. Conventionally, autologous costal cartilage grafts are collected and shaped for transplantation. However, in this method, excessive invasion occurs due to limitations in the costal cartilage collection. Due to deformation over time after transplantation of the shaped graft, problems with long-term morphological maintenance exist. Additionally, the lack of elasticity with costal cartilage grafts is worth mentioning, as costal cartilage is a type of hyaline cartilage. Medical plastic materials have been transplanted as alternatives to costal cartilage, but transplant rejection and deformation over time are inevitable. It is imperative to create tissues for transplantation using cells of biological origin. Hence, cartilage tissues were developed using a biodegradable scaffold material. However, such materials suffer from transplant rejection and biodegradation, causing the transplanted cartilage tissue to deform due to a lack of elasticity. To address this problem, we established a method for creating elastic cartilage tissue for transplantation with autologous cells without using scaffold materials. Chondrocyte progenitor cells were collected from perichondrial tissue of the ear cartilage. By using a multilayer culture and a three-dimensional rotating suspension culture vessel system, we succeeded in creating scaffold-free elastic cartilage from cartilage progenitor cells.     

A Potential Serum N-glycan Biomarker for Hepatitis C Virus-Related Early-Stage Hepatocellular Carcinoma with Liver Cirrhosis

Detection of early-stage hepatocellular carcinoma (HCC) is beneficial for prolonging patient survival. However, the serum markers currently used show limited ability to identify early-stage HCC. In this study, we explored human serum N-glycans as sensitive markers to diagnose HCC in patients with cirrhosis. Using a simplified fluorescence-labeled N-glycan preparation method, we examined non-sialylated and sialylated N-glycan profiles from 71 healthy controls and 111 patients with hepatitis and/or liver cirrhosis (LC) with or without HCC. We found that the level of serum N-glycan A2G1(6)FB, a biantennary N-glycan containing core fucose and bisecting GlcNAc residues, was significantly higher in hepatitis C virus (HCV)-infected cirrhotic patients with HCC than in those without HCC. In addition, A2G1(6)FB was detectable in HCV-infected patients with early-stage HCC and could be a more accurate marker than alpha-fetoprotein (AFP) or protein induced by vitamin K absence or antagonists-II (PIVKA-II). Moreover, there was no apparent correlation between the levels of A2G1(6)FB and those of AFP or PIVKA-II. Thus, simultaneous use of A2G1(6)FB and traditional biomarkers could improve the accuracy of HCC diagnosis in HCV-infected patients with LC, suggesting that A2G1(6)FB may be a reliable biomarker for early-stage HCC patients.     

Suspension pattern and rising height of sedimentary particles with low concentration in a mechanically stirred vessel

In this study, the effects of impeller rotation speed, off‐bottom clearance, blade angle, types of solid and liquid, etc., on the suspension pattern of sedimentary particles and particle rise height in liquid were investigated with a hemispherical vessel without baffles under low particle concentration. The transition conditions of suspension pattern between regimes I and II, and regimes II and III, were observed visually, and their non‐dimensional equations were expressed with an acceptable correlation by varying the above operation factors a great deal. Here, regime I is stagnation of particles on a vessel bottom, II is partial suspension, and III is complete suspension in liquid. The non‐dimensional equation of the maximum particle rise height was also successfully obtained. The combination of the non‐dimensional equations of transition and maximum particle rise height permitted us to determine the adequate solid/liquid mixing operation conditions without collision of particles with device parts.     

Flow visualization and numerical analysis of a new mixing equipment with vibratory fins

The mixing performance of a new type of mixing equipment which has several fin oscillators on a pair of shafts with a vibrating motor was investigated. This mixing equipment, which is mainly used for industrial plating processes, was usually operated at a vibrating frequency of about 40 Hz with the amplitude 1 mm. The flow visualization in this equipment showed that the flow in the vessel at laminar flow region was vertically divided into two distinct symmetric regions. The numerical simulation of the flow and the mixing patterns agreed well with the visualization result at laminar flow region.     

Modeling Grain Boundary Motion and Dynamic Recrystallization in Pure Metals

The current study proposes a new approach of modeling discontinuous dynamic recrystallization in pure copper and cobalt based on the inverse analysis of experimental data. This approach comprises two steps: First, the mobility of grain boundaries is determined by a mean-field model in the steady state regime, then in a second step the information collected (mobility, nucleation frequency) is used to determine the mechanical behavior and the grain size change. The nucleation criterion is reformulated in a more general expression, and a new expression of the nucleation frequency with a single empirical parameter is proposed. The model predicts the stress–strain curves and the evolution of mean grain size, and is in good agreement with experimental data for both copper and cobalt. The modeling procedure requires a minimum of initial material parameters and could be especially attractive in the case of complex metals and alloys for which these parameters are unknown.