Histopathological studies of extracted whole lunate bones obtained from 10 patients with Stage 3 Kienböck’s disease at surgery for tendon-ball replacement were correlated with magnetic resonance imaging (MRI), computed tomography (CT) and tomography images made prior to surgery. A reforming zone, or a reactive interface between the reactive new bone and granulation tissue formation, and new vascularization were observed surrounding the bone necrosis area showing empty lacunae, fatty necrosis, and disappearance of osteoid. Findings of CT, tomography and microradiography of slices of extracted lunate bone confirmed that fractures of the articular cartilage and the subchondral bone occurred secondarily by overloading, and showed the extent of the collapsed area of the lunate. MRI showed complete loss of signal intensity in T1 images of the lesion of the lunate in advanced Stage 3 Kienböck’s disease. MRI is at present unable to distinguish bone necrosis, the histological reactive interface or surrounding hyperaemia in detail. However, the low-intensity arc, or the reactive interface present on MRI in early Stage 3, sometimes correlates with the histological findings of osteoid and granulation zones.
A formulation is presented of elastoplastic stress analysis of a laminated structure on the basis of the finite-element method with use of Voigt's and Reuss's assumptions. Systematic tests were carried out at room and cryogenic temperatures with specimens composed of stainless steel and epoxy resin to depict a slip curve representing strength of the interface. A three-point bending test was performed to measure temperature rise due to slip and to evaluate temperature distribution by a 3-D computer code. quench experiments were also carried out simulating bulk heating with 35-MeV electron beam.< >
Using the SIMION program, we have calculated the trajectories of hydrogen ions to investigate the effects of an E × B filter to be used for hydrogen ion beam injection experiments. The geometry we have utilized for the simulation matches the ion beam transport system of the DT-ALPHA device. Before investigating the hydrogen ion trajectories, we calculated helium ion trajectories and compared the results with experiments using a helium ion beam to confirm the results of the SIMION calculations. We then calculated the trajectories of the hydrogen ions H+, H2+, and H3+. We found that the electric field required to select an H+ ion beam differs from that obtained from a theoretical calculation, and we interpret this as a result of the fringe fields of the E × B filter. We have also evaluated the H+ ion beam size at the ion entrance aperture using SIMION. This calculation indicates that spreading of the hydrogen ions along the electric and magnetic fields differs because of non-homogeneous fields and the fringe fields of the filter. In addition, we have investigated the trajectories and beam sizes of He+ ion beams, we found that the E × B filter has no significant influence on the He+ ion beam experiments.
This paper evaluates the applicability of the extremely low frequency eddy current testing to the monitoring of wall thinning appearing on the inner surface of pipes. Magneto-Impedance sensor arrays are used to detect signals due to wall thinning. Plates made of SS400 with artificial grooves are prepared to simulate wall thinning in a large diameter pipe. We carry out numerical simulations and experiments to evaluate the effect of the depth and width of the grooves on signal. The results show the maximum amplitude and the full width at half maximum of signals correspond approximately to the depth and width of the grooves, respectively.
A thermo-fluid simulation was conducted to clarify heat transfer properties and then to show a design window of the first wall of a Li/V blanket with three-surface-multi-coated channels. Channel dimensions were treated as parameters and their effects on the heat transfer properties and the design window were discussed in the various heat flux of 0.8 to 1.2 MW/m2. In the simulation, the magnetic field of 1 and 10T was assumed in order to investigate how the velocity profiles affect the heat transfer performance. The MHD flow was supposed to be two-dimensional-fully-developed laminar flow. Three-dimensional heat-transfer simulation was conducted with assumption of one-side heating by the constant heat flux on the first wall by using the flow field obtained by the 2D flow analysis. It was found that effects of the flow distributions were small on the heat transfer. The channel height, however, affects the heat transfer characteristics so much and the design window is shown to be limited to relatively small channel dimensions due to the induced stress in the first wall.
This study evaluated the dependence of heat transfer properties of the molten salt mixture LiF–NaF–BeF2 (Flinabe) on the composition ratio to determine its applicability as a coolant in a nuclear system. Specifically, we evaluated the density, specific heat, viscosity, and thermal conductivity using molecular dynamics (MD) simulation and calculated the Prandtl number and figure of merit as heat transfer metrics. The calculated density, specific heat, and viscosity differed from the experimental values by up to approximately 20%. Although the calculated thermal conductivity of Flinabe was not directly comparable due to the lack of accurate experimental measurements, it showed a temperature dependence consistent with that of highly accurate experimental reports for other salts. Overall, the findings of the present study revealed that the ternary Flinabe, specifically LiF–NaF–BeF2 = 33–29–38, had a lower melting point and better heat transfer metrics than conventional candidate LiF–BeF2, making it suitable for use as a coolant.
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