Prediction of Aeroelastic Vibration of Rectangular Cylinders by k-ε Model

The applicability of the k-ε model in the prediction of aerodynamic force and instability is investigated herein. To show that two-dimensional analysis by the k-ε model is different from ordinary two-dimensional analyses that simply neglect the spanwise velocity, an analysis of the aeroelastic vibration of a cross section with B∕D = 2.0 is performed first using the latter method. In this case, motion-induced vortex oscillation was successfully simulated; however, galloping, in which the flapping motion of the separated shear layer plays an important role, could not be simulated. The result shows that physically reasonable flows can not be obtained by ordinary two-dimensional analyses, unless the spanwise momentum diffusion is incorporated correctly. On the other hand, the k-ε model, which incorporates this diffusion process by an eddy viscosity, enables two-dimensional analyses even in the high Reynolds number region. In this paper, applicability of the model is examined for rectangular cross sections with a wide range of B∕D ratio, i.e., 0.6 ≤ B∕D ≤ 8.0. Various typical aerodynamic features calculated using this model were found to be in good agreement with those obtained experimentally, particularly including discontinuities in Strouhal number at the critical cross sections of B∕D = 2.8 and 6.0. Based on this result, an elastically supported B∕D = 2.0 cylinder was analyzed. The motion-induced vortex oscillation and a coupling of the vortex-induced oscillation and galloping were successfully simulated, and their values were in good agreement with those measured in experiments conducted earlier.     

Economical clean dry air system for closed manufacturing system

We demonstrated that the organic carbon contaminants influenced the J-E characteristics of a gate oxide. Molecular-contamination-free clean dry air (CDA) is a choice for the atmosphere control in a closed manufacturing system. The adsorption and desorption characteristics, which are important items for the design and operation of CDA production plants, were confirmed with both a dynamic simulation and a pilot column. Based on the results, we built a CDA plant with a capacity of 4000 m³/h, and confirmed that each contamination concentration was less than 10 ppb. We also proposed the economical CDA system using a power recycle device which has been newly developed. Using this CDA system, it is possible to reduce the power consumption in the CDA plant. Also, it is possible to realize the circulation of the used CDA without generating more contamination or power consumption     

Design and performance evaluation of a haptic interface based on MR fluids for endovascular tele-surgery

Microsystem Technologies - In this paper, a magnetorheological (MR) fluids based haptic interface has been developed in master site to provide the haptic sensation to the interventionalist during...     

Intercalation of PF6 anion into graphitic carbon with nano pore for dual carbon cell with high capacity

Intercalation property of PF₆⁻ into graphitic carbon was studied for a hybrid capacitor with different ratio of cathode and anode amount. Graphene sheet distance increased with increasing PF₆⁻ intercalation amount and it saturated at 0.4 nm at high applied potential, which is corresponded to stage 2 structure. On the other hand, it was found that nano size pore into graphene sheet was introduced at higher applied potential with 20 times larger anode carbon and this nano porous carbon shows a large capacity for intercalation capacity of 147 mAh g⁻¹. The estimated energy density of the hybrid capacitor using carbon with nano bubble structure was ca. 400 Wh kg⁻¹.     

Isolated retrograde amnesia following viral encephalitis

We describe a patient who presented with isolated retrograde amnesia of 2-year duration after recovery from viral encephalitis. The patient was a 29-year-old right-handed male dentist and was admitted to our hospital with a complaint of generalized convulsion. Cerebrospinal fluid (CSF) showed mononuclear pleocytosis. Neuroradiological examinations (X-ray CT, MRI and 123I-IMP SPECT) revealed no significant abnormality. Immunological method showed no specific increase of viral antibody titers. However, with a tentative diagnosis of viral encephalitis, administration of acyclovir was started. After 3 weeks he became comprehensive, and several kinds of neuropsychological tests were performed. His intelligence and immediate memory were normal, and his procedural memory of dentist was intact. On the other hand, he could not recall any information about events, both personal and public, occurred within 2 years before the onset of present illness. His autobiographical memory disorder was also demonstrated using a series of weekly comic. In isolated retrograde amnesia following viral encephalitis like this case, memory of relatively short time duration, acquired prior to the onset of present illness, tend to be disturbed.     

Explicit monotone iterations providing upper and lower bounds for finite element solution with nonlinear radiation boundary conditions

In this paper we consider explicit monotone iterations of the finite element solutions for the radiation cooling problem with the nonlinear boundary conditions. These iterations provide upper and lower bounds, and convergence proofs are given. Finally, we give some numerical examples to demonstrate the effectiveness.     

Field emission monotron for THz emission

Small-signal negative conductance of a field emission monotron was calculated, which was considerably higher than that of a thermionic monotron due to strong bunching of emitted electrons in a field emission. The amplification constant of 28dB/mm is achieved at THz wave region by applying the monotron to a distributed amplifier and is sufficient to overcome power loss in a transmission line. In addition, a wide band frequency tunable electromagnetic wave source may be developed at THz wave region by providing a low loss microstrip line resonator with field emission array due to the gate voltage dependent phase constant of the line.     

A comparison of a 3 day course with a 2 week course of oral prednisolone in patients with chronic asthma

This study was carried out as an attempt to evaluate the relationship between the results of nasal patency examinations and selected anthropometric measurements of nasal cavities in children with complete primary and secondary cleft palate. The examined group consisted of 130 children with cleft palate treated by means of surgery in early childhood owing to their clefts. Concerning the diagnostic methods the study group was divided into two subgroups. Group I consisted of 75 children in whom face photographs in frontal and axial projections towards the external nasal aperture were analysed. Group II consisted of 55 children in whom by means of P-A teleradiography projection the total area, the maximum height and width of nasal cavity were measured separately for the side with cleft and without cleft. The assessment of nasal patency tests using the objective method--active anterior rhinomanometry was carried out.