885 research outputs found
Numerical Simulation of Tsunami Run-up and Inundation Employing Horizontal Two-dimensional Model Based on CIP Method
AbstractA two-dimensional tsunami run-up and inundation model based on a CIP method was developed in this study so as to satisfy the continuity equation with reasonable accuracy. Numerical simulations on tsunami bore were carried out in order to validate the model and discuss the effects of wet-dry condition and overflow condition on the calculation accuracy. As a result, the model was confirmed to be able to represent closely actual water surface profile by using the slip condition on the wet-dry condition. Furthermore, the numerical results without the overflow formula were found to be in good agreement with the experimental ones
Von K\'arm\'an vortex street in a Bose-Einstein condensate
Vortex shedding from an obstacle potential moving in a Bose-Einstein
condensate is investigated. Long-lived alternately aligned vortex pairs are
found to form in the wake, as for the von K\'arm\'an vortex street in classical
viscous fluids. Various patterns of vortex shedding are systematically studied
and the drag force on the obstacle is calculated. It is shown that the
phenomenon can be observed in a trapped system.Comment: 4 pages, 5 figure
Interactively Robot Action Planning with Uncertainty Analysis and Active Questioning by Large Language Model
The application of the Large Language Model (LLM) to robot action planning
has been actively studied. The instructions given to the LLM by natural
language may include ambiguity and lack of information depending on the task
context. It is possible to adjust the output of LLM by making the instruction
input more detailed; however, the design cost is high. In this paper, we
propose the interactive robot action planning method that allows the LLM to
analyze and gather missing information by asking questions to humans. The
method can minimize the design cost of generating precise robot instructions.
We demonstrated the effectiveness of our method through concrete examples in
cooking tasks. However, our experiments also revealed challenges in robot
action planning with LLM, such as asking unimportant questions and assuming
crucial information without asking. Shedding light on these issues provides
valuable insights for future research on utilizing LLM for robotics.Comment: 7 pages, 6 figures, accepted at SII 202
Reactive sintering and particle morphology control of β″-alumina-based water purification filters
This paper reports on the preparation of porous membranes consisting of plate-like β″-alumina grains and the evaluation for microfiltration properties. Porous β″-alumina-based ceramics were prepared by the solid-state reactive sintering of Na2CO3 and α-Al2O3 at 1100–1300 °C. To study the effect of impurities in the starting powder mixtures, LiF-doped membranes were also prepared. As for the water filtration test, the turbidity before and after the vacuum filtration was measured using sintered porous membranes. To simulate bacteria-contaminated water, a suspension of a commercial boehmite powder (D50 = 0.7 μm) in distilled water was used. The non-doped samples sintered at 1200 °C were composed of β″-alumina (84 wt%) and β-alumina (16 wt%) grains and showed a good microfiltration performance; the turbidities before and after filtration were 894.4 NTU and 1.46 NTU, respectively
Rayleigh-Taylor instability and mushroom-pattern formation in a two-component Bose-Einstein condensate
The Rayleigh-Taylor instability at the interface in an immiscible
two-component Bose-Einstein condensate is investigated using the mean-field and
Bogoliubov theories. Rayleigh-Taylor fingers are found to grow from the
interface and mushroom patterns are formed. Quantized vortex rings and vortex
lines are then generated around the mushrooms. The Rayleigh-Taylor instability
and mushroom-pattern formation can be observed in a trapped system.Comment: 5 pages, 4 figure
Mucopolysaccharidosis IVA: Diagnosis, Treatment, and Management.
Mucopolysaccharidosis type IVA (MPS IVA, or Morquio syndrome type A) is an inherited metabolic lysosomal disease caused by the deficiency of the N-acetylglucosamine-6-sulfate sulfatase enzyme. The deficiency of this enzyme accumulates the specific glycosaminoglycans (GAG), keratan sulfate, and chondroitin-6-sulfate mainly in bone, cartilage, and its extracellular matrix. GAG accumulation in these lesions leads to unique skeletal dysplasia in MPS IVA patients. Clinical, radiographic, and biochemical tests are needed to complete the diagnosis of MPS IVA since some clinical characteristics in MPS IVA are overlapped with other disorders. Early and accurate diagnosis is vital to optimizing patient management, which provides a better quality of life and prolonged life-time in MPS IVA patients. Currently, enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT) are available for patients with MPS IVA. However, ERT and HSCT do not have enough impact on bone and cartilage lesions in patients with MPS IVA. Penetrating the deficient enzyme into an avascular lesion remains an unmet challenge, and several innovative therapies are under development in a preclinical study. In this review article, we comprehensively describe the current diagnosis, treatment, and management for MPS IVA. We also illustrate developing future therapies focused on the improvement of skeletal dysplasia in MPS IVA
Modeling of Brittle Crack Propagation/Arrest Behavior in Steel Plates
AbstractTo prevent brittle cracks from causing fatal damage to steel structures, it is needed that steels have enough crack arrestability. However, the brittle crack propagation/arrest behavior has not been explained theoretically enough from the aspect of energy balance and especially the long crack problem has remained as an important unsolved issue for some decades. The authors propose a new model based on local fracture stress criterion to solve the long crack problem. The model considers crack closure effect by uncracked side ligaments formed due to relaxation of plastic constraint progressing with SIF increasing. A simultaneous equation composed of four equations, which formulate local fracture condition, strain hardening, yield point, and dynamic SIF considering side ligaments, is solved to simulate a crack propagation in the model. To validate the model, we compared model simulations with some experiments. Some of them were conducted under the long crack problem condition and obtained the result that they showed good agreements, even under the long crack problem condition. This implies the long crack problem can be explained from the aspect of side ligament development due to the relaxation of plastic constraint
Dynamics of bubbles in a two-component Bose-Einstein condensate
The dynamics of a phase-separated two-component Bose-Einstein condensate are
investigated, in which a bubble of one component moves through the other
component. Numerical simulations of the Gross--Pitaevskii equation reveal a
variety of dynamics associated with the creation of quantized vortices. In two
dimensions, a circular bubble deforms into an ellipse and splits into fragments
with vortices, which undergo the Magnus effect. The B\'enard--von K\'arm\'an
vortex street is also generated. In three dimensions, a spherical bubble
deforms into toruses with vortex rings. When two rings are formed, they exhibit
leapfrogging dynamics.Comment: 6 pages, 7 figure
Capillary instability in a two-component Bose-Einstein condensate
Capillary instability and the resulting dynamics in an immiscible
two-component Bose-Einstein condensate are investigated using the mean-field
and Bogoliubov analyses. A long, cylindrical condensate surrounded by the other
component is dynamically unstable against breakup into droplets due to the
interfacial tension arising from the quantum pressure and interactions. A
heteronuclear system confined in a cigar-shaped trap is proposed for realizing
this phenomenon experimentally.Comment: 7 pages, 6 figure
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