Gas motion in a microgap between a stationary plate and a plate oscillating in its normal direction

Unsteady motion of a gas between two parallel plates is investigated in the case where one of the plates starts (harmonic) oscillation in its normal direction. A kinetic–theoretic approach is employed under the condition that the distance between the two plates is comparable to the mean free path of the gas molecules and/or the frequency of oscillation of the plate is comparable to their mean collision frequency. More specifically, the Bhatnagar–Gross–Krook model of the Boltzmann equation is solved numerically for wide ranges of parameters, such as the Knudsen number and the Mach number, with special interest in the fully nonlinear wave motion. As the result, the time evolution of the local flow field and the periodic state attained at later times are obtained accurately. It is shown that, in the periodic state, one-period average of the momentum (or energy) transferred from the oscillating to the stationary plate takes a nonzero value in contrast to the linear theory, and it becomes minimum at an intermediate Knudsen number (for a given oscillation of the plate and for a given distance between the center of the oscillating plate and the stationary plate).     

Study on heat transfer characteristics of reservoir embedded loop heat pipe (Influence of condenser cooling method on heat transfer characteristics)

As heat generation in satellites increases, securing sufficient radiator panel area is an important problem. Deployable radiators, whose radiator panels are deployed post‐launch in space to increase the effective radiator panel area of the satellite, is becoming an important thermal control technology. A reservoir embedded loop heat pipe (RELHP) is applied to the deployable radiator for a thermal transport device. This paper presents the heat transport dynamic characteristics of a RELHP using a radiant cooling condenser and liquid forced convection cooling condenser by an experimental study. It was found that heat leak into the liquid line, flexible line, and reservoir increases the length of the sub‐cooling region in the condenser. In the case of the radiant cooling condenser, the sub‐cooling region length is shorter than that of a liquid forced convection cooling condenser. Furthermore, vapor temperature is mainly decided by the radiation capacity of the radiator panel, because liquid temperature returned into the evaporator rises with an increase in radiator panel temperature. In addition, time length from start‐up until steady state is greater than the liquid forced convection cooling condenser case, because the radiator panel has a large heat capacity. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20229     

Kinetic Theory of a Spin-1 Bose Condensed Gas at?Finite Temperatures

We derive a kinetic theory of a spin-1 Bose condensed gas at finite temperatures. The theory consists of coupled equations for the condensate and noncondensate. The condensate dynamics is described by a generalized Gross?CPitaevskii (GP) equation including the spin degree of freedom. The condensate and noncondensate atoms interact with each other through the mean field and collisions. From the coupled equations, we determine the condition for static equilibrium of the spin-1 system. We also use the static thermal cloud approximation to derive a generalized GP equation including a dissipative term due to the coupling to a thermal cloud.     

Does the Future Shine Bright for TLA?

Recently there have been hot arguments both for and against investment in Total Laboratory Automation (TLA) in both Japan and the U.S. There is especially much doubt about the underlying economics. As pioneers of TLA, we would like to express our opinion on this. With TLA, the age of pioneers has already ended, yet TLA is currently expanding and we should construct practical systems now. We feel it is not fair to criticize pioneers from the economic side only.The main goal for pioneers in Japan and the U.S. had been what we could do with TLA. We are aware of the criticism from the U.S. that Japan has introduced TLA with no thought of profit due to financial support from the government, but Japan is already changing its course towards a world where profitability is important. Some examples will follow.In this article we mention processes through which the U.S. has come to have doubts about investment effectiveness in TLA, whether it is really dubious economically, the differences between laboratories in Japan and the U.S., and whether the future shines bright for TLA.     

Effects of the porous structures in the porous flow field type separators on fuel cell performances

Effects of separators' several different porous flow field structures consist of spherical alloy powders on the pressure loss characteristics and the single-cell performances were investigated for the purpose of achieving the porous structure which can satisfy the conflicting properties of lower pressure loss and higher power density. Although the separator with partitions in the porous flow field, aimed at improving the uniform oxygen supply ability, indicated higher power density, its pressure loss increased compared to the basic porous flow field type separator. The separator with evenly spaced linear grooves in the porous flow field lowered its pressure loss, however, the maximum power density decreased. On the other hand, the newly designed separator with finely dispersed open space networks in the porous flow field demonstrated lower pressure loss and higher power density; i.e., 50% lower pressure loss and 40% higher power density were obtained compared to the basic porous flow field type separator.     

Characterization of autoinducer 2 signal in Eikenella corrodens and its role in biofilm formation

Quorum sensing (QS) is a process by which bacteria communicate using secreted chemical signaling molecules called autoinducers (AIs). By this process, many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density. In this study, the periodontal pathogen Eikenella corrodens was observed to secrete type 2 signaling molecules. An ortholog of luxS, the gene required for AI-2 synthesis in Vibrio harveyi, was isolated from the E. corrodens genome. A V. harveyi bioassay showed luxS functionality in E. corrodens and the ability of luxS to complement the luxS-negative phenotype of Escherichia coli DH5alpha. AI activity was detected in the supernatant, and the maximum expression of AI-2 was observed during the late exponential phase. To determine the potential role of luxS in the colonization processes, an E. corrodens luxS mutant was constructed and tested for its capacity to form an in vitro biofilm on a polystyrene surface. The biofilm forming efficiency of the luxS mutant was approximately 1.3-fold greater than that of the wild type. These data suggest that a LuxS-dependent signal plays a role in the biofilm formation by E. corrodens.     

Study on the bulk junction type organic solar cells with double zinc oxide layer

The optical and photovoltaic properties of a photovoltaic cell with a structure of indium–tin oxide (ITO)/double ZnO/poly(3-hexylthiophene) (PAT6):PCBM/Ag have been investigated. The double layer ZnO was a composite of a sputtered ZnO layer and oriented zinc oxide nanopillars layer which was fabricated by a new method at low temperature (343 K). It is concluded that the double layer ZnO plays an important role in collecting photogenerated electrons and acts as a conducting path to the electrode. Insertion of the double layer ZnO in the photovoltaic cells produced enhanced performance with the power conversion efficiency of 1.42% under AM1.5 illumination.     

Numerical ordering in a chimpanzee (Pan troglodytes): Planning, executing, and monitoring.

Perceptual and cognitive processes underlying the skill of ordering numerals were assessed in a female chimpanzee (Pan troglodytes) with previous experience in computer-assisted numerical competence tasks. The subject was required to order 3 numerals from the range of 0–9 into an ascending series, with occasional probe trials (referred to as switch trials) in which the positions of the 2nd and 3rd numerals were exchanged immediately after the selection of the 1st. On these trials, errors were scored frequently, whereas correct responses to the intermediate numeral became reliably slower. These and other data indicated that the subject had already established, before making the 1st choice, (a) the correct sequence in which she was to select the numerals and (b) the motor sequence leading to a correct answer. These findings show that a 3-unit ordering task is supported in the chimpanzee, much as it is in humans, by planning, executing, and monitoring phases. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Network structure for control of coupled multiple nonlinear oscillators

In recent research, the morphological effect is widely discussed from walking to the Internet, and its mechanism for generating the functionality has been discovered. In this paper, a module that employs the structural effect for controlling behavior is constructed using coupled nonuniform van der Pol oscillators. We first examine the synchrony of two types of oscillators focusing on number; then, an oscillator module that changes its synchrony from structural disposition is constructed. Oscillators are mutually arranged on a ring-shaped network, and an additional connection is used for transformation. The stability of this system is also discussed, and finally, the procedure for designing this structure-sensitive module using more than three types of oscillators is described.     

Outdoor facility measurement system using multiviewpoint stereo measurement

This paper proposes a novel outdoor facility measurement system. The purpose of this system is to enable survey work on roads to be undertaken both safely and efficiently. This system employs a stereo measurement method and measures facility positions by integrating stereo measurement data from multiple viewpoints whose relationship is unknown. The system involves two processes, which consist of recording images in the field and then analyzing those images indoors. The system is set up in the field and stereo images are recorded in a digital camera from several viewpoints around an intersection. The image analysis is divided into three parts. First, the facility positions from each viewpoint are obtained by a stereo measurement method with the aid of an operator. Second, the correspondences between the stereo measurement data from the multiple viewpoints are obtained. Finally, the facility positions and the relationship between the viewpoints are estimated. The second and final stages of this image analysis are performed automatically. This paper presents highly accurate measurement algorithms for this system, which reduces the amount of assistance required from an operator, and describes facility measurement for some actual intersections. © 1999 Scripta Technica, Electr Eng Jpn, 128(2): 24–35, 1999