Isosceles Triangle Cross-section Research Articles

Directional BLUs for Full Resolution Field Alternative Auto-stereoscopic 3D/2D and 2D/3D LCDs

Switching-directional backlight units (BLUs) were designed and prototyped for full resolution field alternate auto-stereoscopic 3D liquid crystal displays (LCDs). Since the design concepts are different for 2D/3D and 3D/2D displays, the switching characteristic of BLU with two confronting illuminating sets, was applied to build 2D mode into 3D display, and 3D mode into 2D display. A design based on the 2D concept required a uniform bilateral prismatic structure with a cross-section of isosceles triangle on the back surface of the functional light-guide plate (LGP). This structure led to an increase in double-sided uniformity, i.e., for double-sided illuminations (2D as primary function of the 2D/3D display), and a decrease in single-sided uniformity, i.e. for single-sided illumination. However, a design that was based on the 3D concept required an angle gradation for the unilateral prisms with a cross-section of a scalene triangle on the back surface of the functional LGP that led to an increase in single-sided uniformity and a decrease in double-sided uniformity (3D as primary function of the 3D/2D display). Both switching concepts were used to display 3D and 2D on the LCDs of small size handheld game devices and still cameras.

Effect of transverse triangular wedges on the behavior of the ash deposition and heat transfer of an inline tube bundle

The experiment was carried out on an inline 6 rows – 3 columns tube bundle. Free air velocity and coal fly ash feed rate were kept constant at 2.1 ms−1 and 3.65×10−4kgs−1, respectively. The wedges have isosceles triangle cross section and have the same height. The investigation is carried out for four ratios of base to height or aspect ratio: 0.275, 0.550, 0.758 and 1. The wedges are installed transversely across the bundle cross section and parallel to the tubes at the tube bundle inlet, between the second row and the third row, between the fourth row and the fifth row, or at the tube bundle outlet. It is found that flow patterns of the single-phase air flow (SPF) over the tube bundle and the deposition patterns around the tube are related. The deposition coverage angles at the tube upstream start from the points having zero wall flow shear stress and where the flow is toward the surface and having zero wall flow shear stress and where the flow is outward from the surface for the first-row tube and the rest, respectively. For both cases, the ash continues to deposit on the surface to the point having maximum wall shear stress. The average rate of the increase in the shear stress over the coverage angle is an important parameter for predicting the deposition. The deposition decreases as the average rate over the upstream tube surface decreases. It decreases significantly at the adjacent tubes upstream and downstream of the wedges. Based on the deposition and the heat transfer, the optimum wedge position is in the vicinity of the middle length of the tube bundle. In addition, the deposition and the heat transfer decreases and increases with the wedge aspect ratio. In terms of the enhancement of the heat transfer for the same air pumping power, a wedge with an aspect ratio of 0.550 or 0.758 should be installed at the tube bundle inlet.

CFD analysis for thermal performance augmentation of solar air heater using deflector ribs

This paper presents the effect of deflector ribs on the thermal performance of flat plate solar air heater using Computational Fluid Dynamics (CFD) methodology. The analysis is carried out using two-dimensional computational domain for the Reynolds number range of 6000-18000. RNG k-є turbulence model is used to capture the turbulence characteristics of the flow. The deflector rib has a cross-section of isosceles triangle and is placed transversely with respect to the flow. The distance between consecutive ribs is varied as 40mm, 80mm, 160mm and 320mm while the air gap height is varied as 2mm, 3mm, 5mm and 10mm. The numerical model is validated against the well-known correlation of Dittus-Boelter for smooth duct. The simulation results reveal that the presence of deflector ribs provide augmented heat transfer through flow acceleration and enhanced turbulence levels. With reference to smooth duct, the maximum achieved heat transfer improvement is about 1.39 times for the inter-rib distance of 40mm and an air gap height of 3mm while the maximum fiction factor achieved was about 3.82 times for pitch value of 40mm and air gap height of 3mm. The highest thermal enhancement factor is achieved for the pitch value of 320mm and an air gap height of 3mm at Re=6000. The air gap height value of 10mm exhibits thermal enhancement factor values lesser than 1.0 and hence is not recommended for use as heat transfer enhancement device for the entire Reynolds number range used in the analysis. The pitch value of 320 mm exhibits thermal enhancement factor greater than 1.0 for almost all the Reynolds number range used in the analysis and varies between 0.93 and 1.07.

Switching directional BLUs for full-resolution auto-stereoscopic 3D/2D and 2D/3D LCDs

Directional backlight unit (BLU) design concept was applied to realize full-resolution field alternate auto-stereoscopic liquid crystal displays (LCDs) with built-in 3D/2D and 2D/3D. The application-oriented BLU design requires priority in realizing 2D mode or 3D mode. The switching characteristic of BLU with two confronting illuminating sets was applied to build 2D mode into 3D display and 3D mode into 2D display. An LCD with 2D mode as primary function requires higher double-sided luminance uniformity than 3D mode. On the other hand, an LCD with 3D mode requires higher single-sided luminance uniformity than 2D mode. For increasing the double-sided luminance uniformity for 2D mode as a primary function of the display, the former BLU design was realized by using uniform prismatic structure, that is, using uniform bilateral prismatic structure with a cross section of isosceles triangle on the back surface of the light-guide plate. For increasing single-sided luminance uniformity for 3D mode as a primary function of the display, the latter was realized by using graded angle design, that is, unilateral prisms with a cross section of a scalene triangle on the back surface of the light-guide plate. The LCDs of small-sized-handheld game devices and still cameras were fabricated using the 3D/2D and 2D/3D displays.

57.1: Directional BLU for Full Resolution Field Alternative Auto‐Stereoscopic 3D/2D and 2D/3D LCDs

AbstractSwitching directional backlight units (BLUs) were designed and prototyped for full resolution field alternative autostereoscopic 3D liquid crystal displays (LCDs). The inherent switching characteristic of the backlight unit (BLU) in which two confronting illuminating light sources were mounted on the sides of a light‐guide plate (LGP), was applied to build 2D into 3D and 3D into 2D in the LCDs.The design based on 2D concept required a uniform bilateral prismatic structure with a cross section of isosceles triangle on the back surface of the functional LGP. The structure of bilateral‐prismatic LGP and two confronting illuminating sides led to an increase in double uniformity, i. e. for doubleside illuminations, and a decrease in single uniformity, i. e. for single side illumination (2D as primary function of the display; 2D/3D). However, a design that was based on 3D concept required angle gradation for the unilateral prisms on the back surface of the functional LGP that led to an increase in single uniformity and a decrease in double uniformity (3D as primary function of the display; 3D/2D). Both switching concepts were used to display 3D and 2D on LCDs of small size handheld game devices and still cameras.

Quasi-Ballistic Hole Transport in an AlGaN/GaN Nanowire

An AlGaN/GaN nanowire, with an isosceles-triangle cross-section, was designed to create a large negative polarization at the (000-1) facet. The resultant band bending at this interface formed a two-dimensional potential well that accumulated a hole gas. Transistor operation based on the two-dimensional hole gas showed characteristics of quasi-ballistic transport. A small number of elastic scattering sites were evident from quantum interference characteristics in the current-voltage data.

Stationary Fluid Dynamic Behaviour of V-Shaped Diffuser/Nozzle Elements for Valveless Micropump

A novel type of V-shaped (isosceles triangle cross-section) diffuser/nozzle element is proposed for use for valveless micropump. Stationary fluid dynamic behaviour of V-shaped diffuser/nozzle elements in a valveless micropump is investigated by experiment and simulation. Both the results agree well with each other when the Reynolds number is higher than 100 and the pressure loss coefficient ratio of micropump nearly always keeps a constant. For a single V-shaped diffuser, the general trends of variation of pressure loss coefficient with opening angle and Reynolds number are opposite in small and large angles. Compared with conical and flat-wall diffusers, V-shaped diffuser shows the smallest pressure loss when the Reynolds number is 200.

On a Fundamental Formula of a Viscous Fluid

In this paper it was shown that the equation δ∫∫∫Φd×dxdydz=0, which expresses that the dissipation of energy is minimum, is equivalent to Navier-Stokes'equation, if inertia terms are zero and external forces are derived from a potential. Therefore, if fluid flows under the above condition, we can determine the motion by assuming a suitable velocity distribution and deciding its unknown constants so that they satisfy the above equation. By this method, the flow through a straight pipe with isosceles triangle cross-section was solved. The method was also applied to the flow around a sphere, and Stokes'solution was obtained. Each of these examples shows that this energy method is applicable to those problems with success.

粘性流体の一基礎式について

In this paper it was shown that the equation δ∫∫∫Φd×dxdydz=0, which expresses that the dissipation of energy is minimum, is equivalent to Navier-Stokes'equation, if inertia terms are zero and external forces are derived from a potential. Therefore, if fluid flows under the above condition, we can determine the motion by assuming a suitable velocity distribution and deciding its unknown constants so that they satisfy the above equation. By this method, the flow through a straight pipe with isosceles triangle cross-section was solved. The method was also applied to the flow around a sphere, and Stokes'solution was obtained. Each of these examples shows that this energy method is applicable to those problems with success.