6,955 research outputs found
The motion of bubbles inside drops in containerless processing
A theoretical model of thermocapillary bubble motion inside a drop, located in a space laboratory, due to an arbitrary axisymmetric temperature distribution on the drop surface was constructed. Typical results for the stream function and temperature fields as well as the migration velocity of the bubble were obtained in the quasistatic limit. The motion of bubbles in a rotating body of liquid was studied experimentally, and an approximate theoretical model was developed. Comparison of the experimental observations of the bubble trajectories and centering times with theoretical predictions lends qualified support to the theory
Recent applications of the transonic wing analysis computer code, TWING
An evaluation of the transonic-wing-analysis computer code TWING is given. TWING utilizes a fully implicit approximate factorization iteration scheme to solve the full potential equation in conservative form. A numerical elliptic-solver grid-generation scheme is used to generate the required finite-difference mesh. Several wing configurations were analyzed, and the limits of applicability of this code was evaluated. Comparisons of computed results were made with available experimental data. Results indicate that the code is robust, accurate (when significant viscous effects are not present), and efficient. TWING generally produces solutions an order of magnitude faster than other conservative full potential codes using successive-line overrelaxation. The present method is applicable to a wide range of isolated wing configurations including high-aspect-ratio transport wings and low-aspect-ratio, high-sweep, fighter configurations
A spatially-organized multicellular innate immune response in lymph nodes limits systemic pathogen spread
The lymphatic network that transports interstitial fluid and antigens to lymph nodes constitutes a conduit system that can be hijacked by invading pathogens to achieve systemic spread unless dissemination is blocked in the lymph node itself. Here, we show that a network of diverse lymphoid cells (natural killer cells, γδ T cells, natural killer T cells, and innate-like CD8+ T cells) are spatially prepositioned close to lymphatic sinus-lining sentinel macrophages where they can rapidly and efficiently receive inflammasome-generated IL-18 and additional cytokine signals from the pathogen-sensing phagocytes. This leads to rapid IFNγ secretion by the strategically positioned innate lymphocytes, fostering antimicrobial resistance in the macrophage population. Interference with this innate immune response loop allows systemic spread of lymph-borne bacteria. These findings extend our understanding of the functional significance of cellular positioning and local intercellular communication within lymph nodes while emphasizing the role of these organs as highly active locations of innate host defense
Characterization of Entire Sequences via Double Orlicz Space
Let Γ denote the space of all entire sequences and ∧ the space of all analytic sequences. This paper is a study of the characterization and general properties of entire sequences via double Orlicz space of ΓM2 of Γ2 establishing some inclusion relations
Young\u27s modulus of [111] germanium nanowires
This paper reports a diameter-independent Young’s modulus of 91.9 ± 8.2 GPa for [111] Germaniumnanowires (Ge NWs). When the surface oxide layer is accounted for using a core-shell NW approximation, the YM of the Ge core approaches a near theoretical value of 147.6 ± 23.4 GPa. The ultimate strength of a NW device was measured at 10.9 GPa, which represents a very high experimental-to-theoretical strength ratio of ∼75%. With increasing interest in this material system as a high-capacity lithium-ion battery anode, the presented data provide inputs that are essential in predicting its lithiation-induced stress fields and fracture behavior
A Unified treatment of small and large- scale dynamos in helical turbulence
Helical turbulence is thought to provide the key to the generation of
large-scale magnetic fields. Turbulence also generically leads to rapidly
growing small-scale magnetic fields correlated on the turbulence scales. These
two processes are usually studied separately. We give here a unified treatment
of both processes, in the case of random fields, incorporating also a simple
model non-linear drift. In the process we uncover an interesting plausible
saturated state of the small-scale dynamo and a novel analogy between quantum
mechanical (QM) tunneling and the generation of large scale fields. The steady
state problem of the combined small/large scale dynamo, is mapped to a
zero-energy, QM potential problem; but a potential which, for non-zero mean
helicity, allows tunneling of bound states. A field generated by the
small-scale dynamo, can 'tunnel' to produce large-scale correlations, which in
steady state, correspond to a force-free 'mean' field.Comment: 4 pages, 1 figure, Physical Review Letters, in pres
- …