Search

The dynamic stability of a reentry lifting capsule with a large aftbody was studied by synergistic experimental and numerical investigations. Free-to-rotate wind-tunnel tests showed that self-induced pitch oscillations depended on the Mach number, Reynolds number, and surface roughness. The experiment provided the amplitudes and frequencies of oscillations for numerical simulations in prescribed motions. Both data reduction methods for the damping coefficient are presented, and the time-series results of both methods are compared. The validated numerical simulations enabled detailed visualization of the separated flow on the side surface of the aftbody to investigate the effects of flow separation and attachment on the dynamic stability and the effect of sting interference. The dynamic characteristics observed in a postflight test with a scaled model of the recovered capsule agreed with those of the reconstructed flight in spite of deceleration effects. Wind-tunnel testing and numerical simulations as well as their mutually validated investigations provided sufficient information to fly the small lifting capsule.

Objective: To elucidate the prevalence of developmental anomalies of permanent lateral incisors among young patients in Japan. Study deign: A total of 1375 patients were observed between 1990 and 2008 at the Department of Pediatric Dentistry in the Kyushu Dental College Hospital and four private pediatric dental clinics in Kitakyushu City. Panoramic and periapical radiographs were examined for all those patients aged 5 to 19 years. Results: The prevalence of agenesis of the lateral incisors was 7.3% (100 patients), with more girls than boys being affected. The prevalence rates of absent upper and lower lateral incisors were 2.7 and 4.8 % (34 and 63 patients), respectively. Nine (0.7 %) of the total patients had microdontia. Eruption disturbance was present in five patients (0.4 %). Two of five patients presented with a disturbed eruption owing to an odontoma or a supernumerary tooth. Conclusion: In our study, the prevalence of agenesis of the lateral incisors was higher in Japanese children than in other populations, and eruption disturbance occurred less frequently than agenesis and microdontia. Nevertheless, the early differential diagnosis of an eruption disturbance is important in order to begin appropriate treatment at the optimal time.

Eighteen trinuclear NiII2LnIII complexes of 2,6-di(acetoacetyl)pyridine (H2L) (Ln=La-Lu except for Pm) were prepared by a "one-pot reaction" of H2L, Ni(NO3)2.6H2O, and Ln(NO3)3.nH2O in methanol. X-ray crystallographic studies indicate that two L2- ligands sandwich two NiII ions with the terminal 1,3-diketonate sites and one LnIII ion with the central 2,6-diacylpyridine site, forming the trinuclear [Ni2Ln(L)2] core of a linear NiLnNi structure. The terminal Ni assumes a six-coordinate geometry together with methanol or water molecules, and the central Ln assumes a 10-coordinate geometry together with two or three nitrate ions. The [Ni2Ln(L)2] core is essentially coplanar for large Ln ions (La, Ce, Pr, Nd) but shows a distortion with respect to the two L2- ligands for smaller Ln ions. Magnetic studies for the Ni2Ln complexes of diamagnetic LaIII and LuIII indicate an antiferromagnetic interaction between the terminal NiII ions. A magnetic analysis of the Ni2Gd complex based on the isotropic Heisenberg model indicates a ferromagnetic interaction between the adjacent NiII and GdIII ions and an antiferromagnetic interaction between the terminal NiII ions. The magnetic properties of other Ni2Ln complexes were studied on the basis of a numerical approach with the Ni2La complex and analogous Zn2Ln complexes, and they indicated that the NiII-LnIII interaction is weakly antiferromagnetic for Ln=Ce, Pr, and Nd and ferromagnetic for Ln=Gd, Tb, Dy, Ho, and Er.

Dynamic stability tests of a reentry lifting capsule were conducted in the JAXA 2 m × 2 m Transonic Wind Tunnel (JTWT). A single degree-of-freedom (1-DOF) free-rotation test method was employed as former Japanese ballistic capsules of OREX and HAYABUSA (MUSES-C). The pitching and yawing angular motion of the HTV Return Vehicle (HRV) models were simulated independently. The angular motion depended on the Mach number, Reynolds number, roughness elements, and moments of inertia of the models. A Fourierseries formula was used to fill the gap in the discrete time-series data of angular motion, and the static stability and damping coefficients were calculated algebraically. The obtained damping coefficients of various test conditions are compared and discussed.

An assembly of Co3O4 nanocrystals dispersed in an amorphous silicate was prepared by calcination of molecular sieve soaked in precursor solution with the concentration of 0.1 mol/l. We observed the disappearance of antiferromagnetic phase transition at 33 K of bulk Co3O4, and frequency dependence of the cusp temperature below 30 K in the AC susceptibility measurement. Divergent peaks at around 18 and 22 K were observed in the nonlinear susceptibility measurement, implying that the sample is in the spin-glass phase. The magnetic interparticle interactions were collective for the Co3O4 nanocrystals dispersed in nonmagnetic silicate.

The wake integration method, a method that analyzes aerodynamic forces by integration in the wake of a model, was applied to three-dimensional CFD data and a quantitative assessment of aerodynamic forces produced by airplane elements was performed. The method allows the drag force exerted on a body to be decomposed into profile and induced drag components, and provides their distributions. By using this method, a designer can expect to obtain insight into aerodynamic drag production factors from CFD data and wind tunnel wake traverse data. In this study, CFD spatial data of the DLR F6 wing-body model were analyzed and the insights gained into the aerodynamic force distributions were examined.

Dental trauma in childhood requires emergency treatment that might range from a simple repositioning, through replantation, to root as well as pulp treatment and apexification depending on severity of the injury. The trauma may be complicated with the existence of supernumerary teeth, and orthodontic treatment other than the management of trauma may be needed either for complication of the traumatized teeth or already existed occlusion problems. We report the management and long-term follow-up of a rare case in a child with traumatically avulsed maxillary incisor accompanied by mesiodens. The patient had a severe trauma to the face, which resulted in avulsion of the maxillary central incisor. Immediate replantation within 30 min after the trauma was performed. Radiographic examination also showed the mesiodens. Since external resorption started during follow-up, and electric pulp testing indicated negative response, we performed root treatment and apexification by calcium hydroxide. The mesiodens was extracted after the stabilization of the patient, followed by orthodontic treatment for the maxillary protraction. Although ankylosis occurred in long-term follow-up, no discomfort in the daily life with good prognosis was noticed.