Performance of a new low‐cost laser disdrometer with rainfall intensity correction in heavy rainfall

Recently, a new low‐cost disposable laser disdrometer with the capacity for hydrometeor imaging was proposed by the authors. The laser disdrometer has the drawback of detecting false raindrops, which are splashed droplets and pooled water drops on the housing. Actual raindrops can be sorted from false raindrops by their different fall speeds, but the large size and slow falling speed of false raindrops induce significant observational dead time, affecting the raindrop capture rate and the number density of the raindrops. The ratio between the actual number of raindrops and the total number of drops including the false raindrops provides a reasonable rain intensity correction. This report describes the performance of a laser disdrometer with rain intensity correction in heavy rainfall. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Hybrid integration of smart pixels by using polyimide bonding:demonstration of a GaAs p-i-n photodiode/CMOS receiver

The fabrication procedure of smart pixels based on a hybrid integration of compound semiconductor photonic devices with silicon CMOS circuits is described. According to the 0.8-μm design rule, CMOS receiver/transmitter circuits are designed for use in vertical-cavity surface-emitting laser (VCSEL)-based smart pixels, and 16×16 and 2×2 Banyan-switch smart-pixel chips are also designed. By using our polyimide bonding technique, we integrated GaAs pin-photodiodes hybridly on the CMOS circuits. The photodetector (PD)/CMOS hybrid receiver operated error free at up to 800 Mb/s. Successful optical/optical (O/O) operation (a bit rate up to 311 Mbit/s) of the 2×2 Banyan-switch smart-pixel chip implemented with another VCSEL chip is also demonstrated     

Effects of Winding Attachment Positions on Output Characteristics of Flux‐Modulating Synchronous Machines

The flux‐modulating synchronous machine (FMSM) is a new type of multipole SM with nonoverlapping concentrated armature and field windings on the stator. This paper compares the output characteristics of two FMSMs through finite element analysis (FEA) and experiments. In both of the FMSMs, the attachment positions of the armature and field windings are swapped. To determine the reason for the discrepancies in their output characteristics, unsaturated inductances were calculated using a d‐‐q equivalent circuit. In addition, the calculated results of the inductances were confirmed through a visualization of the leakage fluxes using FEA. The results of the study show that the synchronous inductance can be reduced by attaching the armature winding to the air‐gap side of the stator teeth and that the reduction leads to an increase in output power.     

Inhibition of char deposition using a particle bed in heating section of supercritical water gasification

Supercritical water gasification (SCWG) has attracted attention as a technology for utilizing wet biomass. We used a fluidized bed of alumina particles to prevent blockage of a SCWG reactor. A glucose solution was heated in the reactor with and without fluidized alumina particles. In the absence of alumina particles, char particles formed homogeneously in the reactor, but the use of a fluidized bed resulted in accumulation of char particles at the reactor’s exit rather than inside the reactor. Therefore, the fluidized bed was effective at preventing blockage of the reactor. However, the alumina particles did not remove deposits from the reactor’s walls. Instead, the fluidized bed caused larger char particles to form, preventing their adhesion to the reactor’s wall.     

Studies on thrust characteristics of high‐thrust spiral motor

Linear actuators are used in various industrial applications. Conventional linear actuators are a combination of a rotational motor and a ball screw, a hydraulic actuator, or a linear motor. However, these actuators have some demerits. This paper proposes a spiral motor (SPRM) that comprises a helical stator and a helical mover. Owing to its helical structure, the SPRM can be expected to show better performance compared to the conventional linear actuator. A stator and a mover are shown in Figs. 1 and 2, respectively. Helical motion is obtained by this motor and only linear motion is extracted by canceling rotational motion at the end effector. There are two types of SPRMs. One has no ball screw on the output axis, while the other has a ball screw. The former can be used in a direct drive system. However, the gap between the stator and the mover should be controlled because the motor is a magnetic levitation system without a ball screw. Further, the motor requires two three‐phase inverters. The other motor is easy to control because it does not require gap control. However, the motor is inferior to the first motor with regard to position control since the friction in this motor is larger. In this study, a prototype of the SPRM is developed. The prototype constructed is a motor with a ball screw. In this motor, the stator and mover are made of block cells. The stator block is shown in Fig. 3 and the mover block is shown in Fig. 4. The prototype of the SPRM shown in Fig. 5, is developed by using these two blocks. An experiment is conducted to examine the driving of the SPRM. The experimental result is shown in Fig. 6. From this result, it is evident that comprising a helical stator and a helical mover can generate linear motion. Another experiment is conducted for measuring the thrust characteristic of the motor. The result obtained is shown in Fig. 7. From the figure, the thrust constant of the spiral motor, K_f, is obtained as 538.0 N/A. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(2): 58–64, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21168     

Thermodynamic stability of hydrogen+tetra-n-butyl phosphonium bromide mixed semi-clathrate hydrate

Three-phase equilibrium (pressure–temperature) relation of hydrate+aqueous+fluid phases for the hydrogen (H₂)+tetra-n-butyl phosphonium bromide (TBPB)+water ternary system was investigated in a temperature range of 281.90–295.94 K and a pressure range up to 170 MPa. The behavior of the three-phase coexisting curve indicates no structural transition in the present experimental region. The Raman spectra obtained in the H₂+TBPB mixed semi-clathrate hydrate crystal reveal that H₂ molecule occupies only small cage compartmentally and the TBPB molecule is encaged with a set of other large cages.     

A control method with pheromone information for a transport system

Since the control methods of a transport system between processing machines are specialized for each layout of the system, it is difficult to design prompt schedules and control logic for new complicated systems, especially in cases of machine faults or restructuring the system to modify the layout. In this article, we describe a multiagent transport control system which utilizes pheromone information. Each element of the system acts as an agent and estimates the appropriate path and time to drive out the products using information obtained by communication with other elements as well as pheromone information deposited on the tracks of the products.     

Reconstructing the World’s Museums

Virtual exploration tools for large indoor environments (e.g. museums) have so far been limited to either blueprint-style 2D maps that lack photo-realistic views of scenes, or ground-level image-to-image transitions, which are immersive but ill-suited for navigation. On the other hand, photorealistic aerial maps would be a useful navigational guide for large indoor environments, but it is impossible to directly acquire photographs covering a large indoor environment from aerial viewpoints. This paper presents a 3D reconstruction and visualization system for automatically producing clean and well-regularized texture-mapped 3D models for large indoor scenes, from ground-level photographs and 3D laser points. The key component is a new algorithm called “inverse constructive solid geometry (CSG)” for reconstructing a scene with a CSG representation consisting of volumetric primitives, which imposes powerful regularization constraints. We also propose several novel techniques to adjust the 3D model to make it suitable for rendering the 3D maps from aerial viewpoints. The visualization system enables users to easily browse a large-scale indoor environment from a bird’s-eye view, locate specific room interiors, fly into a place of interest, view immersive ground-level panorama views, and zoom out again, all with seamless 3D transitions. We demonstrate our system on various museums, including the Metropolitan Museum of Art in New York City—one of the largest art galleries in the world.