Numerical simulation of buoyancy-assisting,backward-facing step flow and heat transfer in a rectangular duct

Two- and three-dimensional numerical simulations have been performed for mixed convective upward flows over a backward-facing step in a duct. The Reynolds number, expansion ratio, and aspect ratio (in 3-D simulations) were kept constant at Re = 125, ER = 2, and AR = 16, respectively. The heat flux at the wall downstream of the step was uniform. The straight wall, the step, and the side walls (in 3-D simulations) were assumed to be adiabatic. The effect of the buoyancy level, Ri^*, was the major interest in this study. It was found that the reattachment point and the peak Nusselt number point moved upstream as Ri^* was increased. The secondary recirculation region, which developed at the corner of the step, became larger. A secondary flow was also found in a cross section immediately downstream of the step. Flow directed toward the center of the duct became more intensive as Ri^* increased, which possibly resulted from an increase in the level of three-dimensionality of the flow and thermal fields. © 1999 Scripta Technica, Heat Trans Asian Res, 28(1): 58–76, 1999     

Three-dimensional monolithic microwave integrated circuit technology for fully computer-aided design-compatible monolithic microwave integrated circuit development

This paper presents the advantages of the three-dimensional (3D) masterslice monolithic microwave integrated circuit (MMIC) technology and the application of its technology to computer-aided design (CAD) software. Its high level of freedom in transmission line routing offers design flexibility and the high integration of 3D MMICs. A 20-GHz single-chip receiver and 60 GHz amplifier are demonstrated. The 3D masterslice MMIC technology, an advanced MMIC design method, is effective in making existing CAD software fully CAD compatible by attaching software packages which allow the sharing of parameters between schema and layout, autorouting, customized simulation and database including reference circuits, and so on. Masterslice MMIC CAD software is also developed. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 498–506, 1998.     

Dual Nature of RAGE in Host Reaction and Nurturing the Mother–Infant Bond

Non-enzymatic glycation is an unavoidable reaction that occurs across biological taxa. The final products of this irreversible reaction are called advanced glycation end-products (AGEs). The endogenously formed AGEs are known to be bioactive and detrimental to human health. Additionally, exogenous food-derived AGEs are debated to contribute to the development of aging and various diseases. Receptor for AGEs (RAGE) is widely known to elicit biological reactions. The binding of RAGE to other ligands (e.g., high mobility group box 1, S100 proteins, lipopolysaccharides, and amyloid-β) can result in pathological processes via the activation of intracellular RAGE signaling pathways, including inflammation, diabetes, aging, cancer growth, and metastasis. RAGE is now recognized as a pattern-recognition receptor. All mammals have RAGE homologs; however, other vertebrates, such as birds, amphibians, fish, and reptiles, do not have RAGE at the genomic level. This evidence from an evolutionary perspective allows us to understand why mammals require RAGE. In this review, we provide an overview of the scientific knowledge about the role of RAGE in physiological and pathological processes. In particular, we focus on (1) RAGE biology, (2) the role of RAGE in physiological and pathophysiological processes, (3) RAGE isoforms, including full-length membrane-bound RAGE (mRAGE), and the soluble forms of RAGE (sRAGE), which comprise endogenous secretory RAGE (esRAGE) and an ectodomain-shed form of RAGE, and (4) oxytocin transporters in the brain and intestine, which are important for maternal bonding and social behaviors.     

Characterization of the aramid/epoxy interfacial properties by means of pull-out test and influence of water absorption

Single fiber pull-out tests were carried out to investigate the influence of water absorption on the interfacial properties of aramid/epoxy composite. The fiber/matrix interfacial strength was severely decreased between 4 and 7 week immersion time in deionized water at 80 °C, and thereafter showed a plateau. This change with immersion time did not correspond with that of the water gain of the pull-out specimens, because the water gain did not reflect the one in the fiber/matrix interface. As a result of the degradation of the fiber/matrix interfacial strength, the pulled-out fiber surfaces of 7, 10 and 13 week wet specimen were smooth. In situ observations of interfacial crack propagation by a video microscope and an analysis of acoustic emission (AE) signals showed that AE signals obtained during the pull-out process were classified into four types according to fracture modes. AE signals detected at final unstable crack propagation and fiber breakage had high amplitude and long duration.     

Relaxation behavior of polymers probed by positron annihilation lifetime spectroscopy

Relaxation behaviors of polyethylene, polypropylene, and polycarbonate have been studied by positron annihilation lifetime spectroscopy (PALS). In PALS positron sources made of radioisotopes are used to inject positrons into polymer as a micro probe. The injected positron probes can induce radiation effect, which plays an important role in detecting the polymer relaxation behavior through electrons trapped in shallow potentials at low temperature. Monitoring the intensity (I₃) of ortho-positronium (o-Ps), transitions of γ and δ relaxation can be measured by PALS as a secondary effect. In this experiment, the change of I₃ below Tg is connected with the number of the trapped electrons, which can be excited from the shallow potential by the thermal motion of polymer structures and visible light irradiation. In the PALS measurements of non-irradiated PP samples, relaxation of methyl groups was observed as low as 50 K, which can be assigned as the δ relaxation. Relaxations of β and γ were also observed for the non-irradiated PP samples between 100–370 K. However for the 3 MGy γ-ray irradiated PP samples, only β relaxation was observed because the large radiation dose caused a large number of scissions of –CH₃ groups from main chains and the characteristics changed. For the irradiated samples, radiation hardening was observed. Electronic Publication     

Conditional data processing for single-shot spectral analysis by use of laser-induced breakdown spectroscopy

Schemes of conditional data processing are evaluated based on either the peak-to-base ratio or the signal-to-noise ratio as a metric for analyte detection in single-shot laser-induced breakdown spectra. The analyte signal investigated is the 288.1-nm Si I emission line provided by an aerosol stream of monodisperse 2.5-microm-sized silica microspheres. Both the Si emission line and a spectral region corresponding to continuum emission are used to evaluate the statistical distribution of spectral noise. The probability of false hits is determined by evaluating various conditional processing thresholds. As the detection threshold increases, the rate of detected silica particle hits decreases along with the expected fraction of false-particle hits (i.e., spectral noise). For all threshold values the signal-to-noise ratio is found to provide a more robust metric for single-shot analyte detection compared with the peak-to-base ratio.     

Thermodynamic analysis of the phase transition of polyethylene under high pressure

Mechanism of emergence of high pressure phase of polyethylene is analysed on the thermodynamic stand point: The change in free energy due to pressure increase is calculated for each phase on the basis of the experimental data. The transition temperature and melting point under the increased pressures are estimated and the results obtained are consistent with the observed values.     

Crystallization of amorphous antimony films on silver films

The crystallization process in amorphous antimony films 70–330 Å thick evaporated onto silver films 10–150 Å thick which have previously been evaporated onto glass is directly observed through an optical microscope. The conditions under which the crystallization process in the amorphous antimony films is observed are found to be severely limited by the preparation conditions of the silver films. The crystallization can only be observed on silver films thinner than 30–40 Å which have previously been exposed to oxygen or nitrogen gas. The crystallization thickness of amorphous antimony films on these substrates is estimated to be 123-75 Å as the substrate temperature varies from 20 to 80 °C and the activation energy for crystallization to be 0.23-0.30 eV as the film thickness varies from infinity to 200 Å.     

A high‐speed‐execution method for a program written in factory‐automation‐cell control language

A new programming method called Cell Control Language (CCL) for factory‐automation systems has been developed. In CCL programming, an action sequence of each functional unit in each operation mode is first described as a net module. This net module is a subclass of Petri nets, and this subclass is equivalent to a state‐transition diagram (a conventional design method). Several net modules are merged and translated into an internal code program, which is executed in a cell controller. To improve the ability of the controller to respond to state changes, we developed two new methods based on CCL. One is that for efficiently describing a CCL program, which needs a quick response to state changes, and the other is that for executing the program in a short cycle. The execution method was applied to an actual cell controller, which confirmed that it can improve the ability to respond to state changes without reducing the total control performance. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(2): 34–42, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10167     

Sulfated bile acid in urine of patients with hepatobiliary diseases

The presence of sulfated bile acid in urine of patients with hepatobiliary diseases was recognized by using an Amberlite XAD-2 column for extraction of bile acid and a Sephadex LH-20 column for separation of sulfated (sulfate of either taurine or glycine conjugate) and nonsulfated bile acid (taurine and glycine conjugate). Sulfated and nonsulfated bile acid, obtained after a Sephadex LH-20 column of urinary extract of the patient with acute hepatitis, was identified by thin layer chromatography. Sulfated bile acid showed a spot with different Rf value from that of taurine-conjugated, glycine-conjugated and free bile acid, and solvolysis of sulfated bile acid resulted in a compound with the same Rf value as glycodihydroxycholanoic acid. A large amount of bile acid sulfate was found in urine of patients with hepatobiliary diseases. The sulfated bile acid in these urine samples occupied from 57.1 to 93.3% of total bile acid, and consisted of both di-and trihydroxycholanoic acid (major part, chenodeoxycholic acid). As no solvolysis was carried out in previous works, bile acid sulfate in urine, as described in this paper, was not determined at all.