Biaxial 360-degree scanning LIDAR using a liquid crystal control

Sophisticated non-mechanical technology for LIDARs is needed to realize safe autonomous cars. We have confirmed the operating principle of a non-mechanical LIDAR by combining concentric circular-grating couplers (CGCs) with a coaxially aligned rod lens. Laser light incident vertically on the center of the inner CGC along the center axis of the lens is radiated from the outer CGC and passes through the side surface of the lens. It is converted to a parallel beam that scans in two axes by applying voltages to two area-segmented electrode layers sandwiching the CGCs and a liquid crystal layer formed on the CGCs. We have demonstrated scanning whose motion ranges were 360 degrees horizontally and 10° vertically. A beam with a spread angle of 0.3° × 0.8° at a minimum swept vertically up to a frequency of 100 Hz and ten equally spaced beams scanned rotationally with a 6-degree cycle variation of spread of between 0.8° and 3.5°.

The Focusing Waves Induced by Bragg Resonance with V-Shaped Undulating Bottom

Intensive wave reflection occurs when the wavelengths of the incident waves and bottom undulations are in a 2:1 ratio. Existing studies have included the Bragg resonance phenomenon of waves passing over a continuous undulating bottom parallel to and oblique to the shoreline. More generally, the Bragg resonance mechanism is used as a means of coastal protection, rather than wave power generation. To focus the wave energy in a specific area, here, we propose sinusoidal sandbars of a horizontal V-shaped pattern, which is formed by two continuous undulating bottoms inclined at an angle to each other and the center axis of the angle is perpendicular to the shoreline. Based on the high-order spectral (HOS) numerical model, both the characteristics of Bragg resonance induced by the regular waves and random waves are investigated. In the scenario of regular waves, it shows that the wave-focusing effect is related to the angle of the V-shaped undulating bottom, and the optimal angle of inclination for the V-shaped undulating bottom is 162.24°. On that basis, considering the interactions between the random waves and the V-shaped undulating bottom of 162.24°, the Bragg resonance characteristics of random waves are studied. The BFI factor combining wave steepness and spectrum width can evaluate the focusing intensity of the Bragg resonance of the random waves. For BFI, in the range of 0.15–1.0, the values of Hsmax/Hs0 linearly increase with the increase of BFI.

Inline pseudoelliptic waveguide filters using asymmetric Iris coupled transverse rectangular ridge resonators

In this work, a new structure for the implementation of inline pseudoelliptic waveguide filters using non-resonating modes, based on asymmetric iris coupled transverse rectangular ridge resonators has been proposed. The basic structure is comprised of a ridge that is always centered and transverse to the waveguide center axis and has the ability to create a transmission zero (TZ) above or below the passband without involving any rotation of the ridge, thus enabling quicker design of the resulting filters by allowing the use of more efficient analysis tools like FEST3D, in addition to the more general purpose methods like HFSS. A centered ridge enables the ease of manufacturing through machining. The proposed structure makes use of rectangular waveguide's dominant TE10 mode as a non-resonating mode to create an alternate energy path from source to load, thus realizing a TZ, while the asymmetric irises excite the ridge resonator, enabling the overall structure to act as a singlet capable of producing both a pole and a TZ. A third-order filter with one TZ and a fifth-order filter with two TZs have been designed and manufactured. Measured results show good consistency with the simulated data, validating the viability of the proposed structure.

Two-axis scanning LIDAR using a liquid crystal control

Sophisticated non-mechanical technology for LIDARs is needed to realize safe autonomous cars. We have confirmed the operating principle of a non-mechanical LIDAR by combining concentric circular-grating couplers (CGCs) with a coaxially aligned rod lens. Laser light incident vertically on the center of the inner CGC along the center axis of the lens is radiated from the outer CGC and passes through the side surface of the lens. It is converted to a parallel beam that scans in two axes by applying voltages to two area-segmented electrode layers sandwiching the CGCs and a liquid crystal layer formed on the CGCs. We have demonstrated scanning whose motion ranges were 360 degrees horizontally and 10 degrees vertically. A beam with a spread angle of 0.3 ⨯ 0.8 degrees at a minimum swept vertically up to a frequency of 100 Hz and ten equally spaced beams scanned rotationally with a 6-degree cycle variation of spread of between 0.8 and 3.5 degrees.

Analytical Solution of Three-Dimensional Heaving Displacement of Ground Surface during Tunnel Freezing Construction Based on Stochastic Medium Theory

Many studies indicate that the heaving displacement during tunnel freezing construction can be regarded as a plane strain problem. However, due to the fact that many of the frozen pipes are placed obliquely in practical engineering, it should be a three-dimensional problem. Therefore, considering stochastic medium theory, the analytical solution of three-dimensional heaving displacement of ground surface during tunnel freezing construction is established, and the analytical solution is applied to the project case in Beijing. The calculation results show that, considering the inclination angle between the freezing pipe and the center axis of the tunnel, the maximum heaving displacement of the ground surface occurs at the tunnel center. When the inclination angle is equal to 0°, the analytical solution of three-dimensional ground surface heaving displacement is in good agreement with that of the two-dimensional prediction model, which further verified the reliability of the established analytical solution of the three-dimensional frost heave prediction model.

Komplettbearbeitung von Turbinen- und Spezialwellen

Der Werkzeugmaschinenspezialist Niles Simmons hat den Prozess des „Center Axis Alignment“ zur automatischen In-Prozess-Bestimmung der optimalen Wellenzentrumsachse entwickelt. Aufgrund der hohen Technologieintegration in einer Maschine, der automatisierten Werkzeugbestückung und dem Einsatz komplexer Messverfahren kann eine bedienerlose Komplettbearbeitung prozesssicher abgebildet werden.

A Variational Method for Analyzing Vortex Flows in Radar Scanned Tornadic Mesocyclones. Part I: Formulations and Theoretical Considerations

A variational method is formulated with theoretical considerations for analyzing vortex flows in Doppler radar scanned tornadic mesocyclones. The method has the following features. (i) The vortex center axis (estimated as a continuous function of time and height in the four-dimensional space) is used as the vertical coordinate, so the coordinate system used for the analysis is slantwise-curvilinear and non-orthogonal in general. (ii) The vortex flow (VF), defined by the three-dimensional vector wind minus the horizontal moving velocity of vortex center axis, is expressed in terms of the covariant basis vectors (tangent to the coordinate curves), so its axisymmetric part can be properly defined in that slantwise-curvilinear coordinate system. (iii) To satisfy the mass continuity automatically, the axisymmetric part is expressed by the scalar fields of azimuthally averaged tangential velocity and cylindrical stream-function and the remaining asymmetric part is expressed by the scalar fields of stream-function and vertically integrated velocity-potential. (iv) VF-dependent covariance functions are formulated for these scalar variables and then de-convoluted to construct the square root of background error covariance matrix analytically with the latter used to transform the control vector to precondition the cost-function. (v) The de-convoluted covariance functions and their transformed control variables satisfy two required boundary conditions (that is, zero vertical velocity at the lower rigid boundary and zero cross-axis velocity along the vortex center axis), so the analyzed VF satisfies not only the mass continuity but also the two boundary conditions automatically.

NR4A1 Deletion in Marginal Zone B Cells Exacerbates Atherosclerosis in Mice—Brief Report

Objective: NR4A orphan receptors have been well studied in vascular and myeloid cells where they play important roles in the regulation of inflammation in atherosclerosis. NR4A1 (nerve growth factor IB) is among the most highly induced transcription factors in B cells following BCR (B-cell receptor) stimulation. Given that B cells substantially contribute to the development of atherosclerosis, we examined whether NR4A1 regulates B-cell function during atherogenesis. Approach and Results: We found that feeding Ldlr −/− mice a Western diet substantially increased Nr4a1 expression in marginal zone B (MZB) cells compared with follicular B cells. We then generated Ldlr −/− mice with complete B- or specific MZB-cell deletion of Nr4a1 . Complete B-cell deletion of Nr4a1 led to increased atherosclerosis, which was accompanied by increased T follicular helper cell–germinal center axis response, as well as increased serum total cholesterol and triglycerides levels. Interestingly, specific MZB-cell deletion of Nr4a1 increased atherosclerosis in association with an increased T follicular helper–germinal center response but without any impact on serum cholesterol or triglyceride levels. Nr4a1 −/− MZB cells showed decreased PDL1 (programmed death ligand-1) expression, which may have contributed to the enhanced T follicular helper response. Conclusions: Our findings reveal a previously unsuspected role for NR4A1 in the atheroprotective role of MZB cells.

Derivation of a Design Solution for the Conservation of a Historical Payab in the Redevelopment of Doloeei, Gonabad

This paper aims to demonstrate the conservation process of historic underground water access or Payab by proposing a multistage decision-making design in Gonabad city, northeast part of Iran. The Payab was in the center axis of a street in the proposed development of a new road which appeared to be against the new construction. The challenge was to develop the new road in the central axis without disturbing much the historic structure in the location. Hence, a request was made to keep both the new road and the historic Payab structure with a design solution. In order to tackle the design solution requested, a qualitative methodology was designed by way of site surveys, site documentation, graphical analysis and interviews. The findings of the research demonstrated contradicting opinions among the governors-laypeople, youngers-elders and males and females about the historic structure. Based on the findings, it was proposed that a protective shield, which aimed to conserve the historic structure under the weight of the new road is required, with a new entrance to be provided through an adjacent sidewalk to achieve consensus among those of diverse ideas. As a conclusion, conservation projects as demonstrated in this paper, like any other conservation projects elsewhere are faced with budget limitation, poor planning and the support it needed. As the historic structure has been part of the local built environment, the integration with other architectural elements in the context is of paramount importance to support the sustainability of the local built environment.