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This paper presents the numerical studies on the effect of atmospheric turbulence on sonic boom signatures. The authors developed the SPnoise for Sonic Boom, which is a numerical analysis code to simulate the essential effect of atmospheric turbulence on sonic booms, i.e., fluctuation of the medium due to turbulence and focusing/defocusing of a sharp wavefront as a result of diffraction. Waveforms obtained from SPnoise for Sonic Boom are compared with those by sonic boom measurements from D-SEND#2, the second flight test of the Drop Test for Simplified Evaluation of Non-symmetrically Distributed Sonic Boom project, and fairly good agreement between simulated and measured waveforms is achieved. [ABSTRACT FROM AUTHOR]

This Paper introduces an extension of so-called multipole analysis, which reduces the computational cost associated with predicting a supersonic vehicle's sonic boom signature on the ground. Multipole analysis enables the modification of the near-field waveform of a supersonic flight vehicle to account for the effect of coalescence in the circumferential direction, even in the same position as the extracted waveform, which results in a large reduction of the computational region of the computational fluid dynamics analysis in the vehicle's vicinity. However, multipole analysis cannot consider a flowfield with lateral asymmetry, which often occurs when dealing with practical vehicle configurations or real flight conditions. The authors have implemented a multipole analysis tool named MPnoise and extended the tool to laterally asymmetric flowfields. It is shown in this Paper that such an extension is easily accomplished by introducing sinusoidal terms into the original, laterally symmetric formulation of multipole analysis. Also shown is a successful convergence between waveforms computed with and without multipole analysis, even when the flowfield has a slight asymmetry in the lateral direction. [ABSTRACT FROM AUTHOR]

In this paper, we report on the creation of a virtual surface using a MEMS tactile display and its quantitative analysis. The display consists of 3 × 3 large-displacement MEMS actuators with hydraulic amplification mechanisms. The MEMS tactile display that we developed can create virtual surfaces that generate various tactile feelings at human fingertips by controlling the displacement, vibration frequency, and period of actuation of the actuators. To quantitatively characterize the virtually created surfaces, we newly proposed a sample comparison method. We compared the tactile feelings with those of 18 samples, such as wood, urethane foam, and sandpaper. These samples were characterized with respect to roughness and hardness using a laser microscope and a compression testing machine. The subjects were requested to select one of these samples that had a tactile texture most similar to the one created by the tactile display. From the experimental results, we could deduce a relationship between the driving conditions of the actuators and the roughness and hardness of the selected samples, and thus, the virtually created surfaces. We experimentally found that the displacement of actuators had a strong correlation with roughness whereas the display created hard surfaces under the tested driving conditions. [ABSTRACT FROM AUTHOR]

Boundary-layer transition on axisymmetric bodies at a nonzero angle of attack in Mach 2 supersonic flow was investigated using experimental measurements and linear stability analysis. Transition over four axisymmetric bodies (namely, the Sears-Haack body, the semi-Sears-Haack body, the straight cone, and the flared cone) with different axial pressure gradients was measured in two different facilities with different unit Reynolds numbers. The semi-Sears-Haack body and flared cone were designed specifically to achieve a broader range of axial pressure distributions. Measurements revealed a dramatic effect of body shape on transition behavior near the leeward plane of symmetry. For a body shape with an adverse pressure gradient (that is, a flared cone), the measured transition patterns show an earlier transition location along the leeward symmetry plane in comparison with the neighboring azimuthal locations. For a nearly zero pressure gradient (that is, the straight cone), such leeward-first transition is observed only at the larger unit Reynolds number. Finally, transition occurs farther downstream along the leeward plane for the remaining two body shapes with a favorable pressure gradient. The observed transition patterns are partially consistent with the numerical predictions based on linear stability analysis. [ABSTRACT FROM AUTHOR]

A method for predicting sonic boom waveforms emanating from a vehicle flying at supersonic speed is presented and compared to flight-test data. The prediction is achieved through three main steps: searching for the position of the sound source along the flight path, predicting the near-field waveform by a combination of computational fluid dynamics simulations on structured and unstructured meshes, and propagating this waveform to the far field by a numerical solver of the augmented Burgers equation. It is shown that this framework successfully predicts sonic boom signatures observed during the large-scale first phase of the drop test for simplified evaluation of the nonsymmetrically distributed sonic boom field test recently conducted by our research group at the Japan Aerospace Exploration Agency for both conventional N waves and lower-amplitude flattop waveforms. [ABSTRACT FROM AUTHOR]

This paper describes an effective method to create a new ideal pressure distribution for designing a three-dimensional natural-laminar-flow wing at high-Reynolds-number conditions to reduce friction drag of a large-size supersonic transport with 300 passengers. This ideal pressure distribution consists of a useful functional form with parameters that are adjusted to be widely applicable to general wing planforms. Furthermore, this research proposes an improvement to the design flow of a conventional computational-fluid-dynamics-based inverse design method developed previously by the Japan Aerospace Exploration Agency for a natural-laminar-flow wing design. An idealized pressure distribution and its validity to achieve approximately 35% laminar flow region of the wing surface on a cranked arrow type planform are presented at the condition of Mach 2.0 and high Reynolds number of approximately 126 million based on mean aerodynamic chord. A representative cross-sectional shape of the designed wing is introduced as an example, and it is shown that a distinguishing feature is characterized by a smaller curvature near the attachment line. A further ideal pressure distribution for an Ogee-type planform with swept angle varied continuously in spanwise direction is then created as a test case for more complicated planforms. [ABSTRACT FROM AUTHOR]

Ciliogenesis is regulated by context-dependent cellular cues, including some transduced through appendage-like structures on ciliary basal bodies called transition fibers and basal feet. However, the molecular basis for this regulation is not fully understood. The Odf2 gene product, ODF2/cenexin, is essential for both ciliogenesis and the formation of the distal and subdistal appendages on centrioles, which become basal bodies. We examined the effects of Odf2 deletion constructs on ciliogenesis in Odf2-knockout F9 cells. Electron microscopy revealed that ciliogenesis and transition fiber formation required the ODF2/cenexin fragment containing amino acids (aa) 188-806, whereas basal foot formation required aa 1-59 and 188-806. These sequences also formed distal and subdistal appendages, respectively, indicating that the centriole appendages are molecularly analogous to those on basal bodies. We used the differential formation of appendages by Odf2 deletion constructs to study the incorporation and function of molecules associated with each appendage type. We found that transition fibers and distal appendages were required for ciliogenesis and subdistal appendages stabilized the centrosomal microtubules. [ABSTRACT FROM AUTHOR]

Abstract: Vascular endothelial growth factor (VEGF) is a disulfide-linked dimeric glycoprotein that enhances vascular permeability, induces chemotaxis and activation of monocytes/macrophages, and promotes growth of vascular endothelial cells. Furthermore, VEGF is a multifunctional cytokine, which influences neural cells directly, enhancing neuronal survival, axonal outgrowth, and Schwann cell proliferation. So far studies of the skin of amyotrophic lateral sclerosis (ALS) have shown unique pathological and biochemical abnormalities in collagen, elastic fibers, and the ground substance. However, the expression of VEGF in ALS skin has not previously been studied. We made a quantitative immunohistochemical study of the expression of VEGF in the skin from 15 patients with ALS and 15 control subjects. VEGF immunoreactivity was markedly positive in the epidermis and moderately positive in some dermal blood vessels and glands in ALS patients. These findings became more conspicuous as ALS progressed. The optical densities for VEGF immunoreactivity of the epidermis in ALS patients were significantly higher (p <0.001) than in control subjects. In addition, there was an appreciable positive correlation (r =0.85, p <0.001) in ALS patients between the densities for VEGF immunoreactivity and duration of illness, but there was no such correlation in control subjects. These data suggest that changes of VEGF in ALS skin are likely to be related to the disease process and that metabolic alterations of VEGF may take place in the skin of patients with ALS. [Copyright &y& Elsevier]

Cilia are force-generating and -sensing organelles that serve as mechanical interfaces between the cell and the extracellular environment. Cilia are present in tissues that adaptively respond to mechanical loading and fluid flow, and defects in ciliary function can lead to diseases affecting these tissues. As might be expected for a mechanical interface, the formation of cilia is, itself, regulated by mechanical forces, and these links between mechanics and ciliary formation are providing new entry points for dissecting the regulatory pathways of ciliogenesis.