Effective Zone Structure by Use of MLCR Method forRadio ATM Entrance Network

The aim of this paper is to effectivelyconstruct zones in a radio ATM entrance network. A QoSindex is newly proposed in order to consider both celltransfer delay and cell loss rate. The QoS index shows the optimal number of access points coveringeach zone and also shows the allowable user trafficintensity. It is clarified that the modulation levelcontrolled radio method can reduce the number of APs and accommodate more user traffic intensitycomparing with QPSK method.     

Toward integrated product and process life cycle planning—An environmental perspective

Life cycle engineering (LCE) is a key concept for promoting environmentally sustainable practices among manufacturing firms. A major hurdle in the implementation of LCE is the lack of a systematic and strategic method to design or plan an entire product life cycle. To address this issue, this keynote provides a framework for life cycle development and proposes the concept of life cycle planning. This paper aims to provide explicit and systematic methodologies for life cycle planning by reviewing this research area. Practical cases that employ life cycle planning are also illustrated. Finally, some research directions are suggested.     

Strategy to improve the performance of dye-sensitized solar cells: Interface engineering principle

As next generation solar cells, dye-sensitized TiO₂ solar cells attract many scientists’ attention throughout the world. Although currently there are no commercially available products on the market, construction of large modules and long-term stability tests have been carried out by many companies and laboratories worldwide; commercialized DSC products may be appearing in the near future. Improving DSC performance and long-term stability is a great challenge not only to the academic research but also for industrial applications. Here the interface molecular engineering principle is proposed as the main strategy to meet this challenge in view of recent progress in this domain.     

Advanced Glycation End-Products Induce Apoptosis of Vascular Smooth Muscle Cells: A Mechanism for Vascular Calcification

Vascular calcification, especially medial artery calcification, is associated with cardiovascular death in patients with diabetes mellitus and chronic kidney disease (CKD). To determine the underlying mechanism of vascular calcification, we have demonstrated in our previous report that advanced glycation end-products (AGEs) stimulated calcium deposition in vascular smooth muscle cells (VSMCs) through excessive oxidative stress and phenotypic transition into osteoblastic cells. Since AGEs can induce apoptosis, in this study we investigated its role on VSMC apoptosis, focusing mainly on the underlying mechanisms. A rat VSMC line (A7r5) was cultured, and treated with glycolaldehyde-derived AGE-bovine serum albumin (AGE3-BSA). Apoptotic cells were identified by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. To quantify apoptosis, an enzyme-linked immunosorbent assay (ELISA) for histone-complexed DNA fragments was employed. Real-time PCR was performed to determine the mRNA levels. Treatment of A7r5 cells with AGE3-BSA from 100 µg/mL concentration markedly increased apoptosis, which was suppressed by Nox inhibitors. AGE3-BSA significantly increased the mRNA expression of NAD(P)H oxidase components including Nox4 and p22^phox, and these findings were confirmed by protein levels using immunofluorescence. Dihydroethidisum assay showed that compared with cBSA, AGE3-BSA increased reactive oxygen species level in A7r5 cells. Furthermore, AGE3-induced apoptosis was significantly inhibited by siRNA-mediated knockdown of Nox4 or p22^phox. Double knockdown of Nox4 and p22^phox showed a similar inhibitory effect on apoptosis as single gene silencing. Thus, our results demonstrated that NAD(P)H oxidase-derived oxidative stress are involved in AGEs-induced apoptosis of VSMCs. These findings might be important to understand the pathogenesis of vascular calcification in diabetes and CKD.     

Heat transfer characteristics of fluid flow in an annulus with an inner rotating cylinder having a labyrinth structure

The convective heat transfer coefficient was experimentally investigated in an annulus with an inner rotating cylinder to estimate the thermal fatigue of the inner and outer cylinders on the rotating machine. The following three conclusions were obtained: (1) Within the range of the experimental conditions, the heat transfer coefficient did not depend on the axial flow rate; rather, it showed a larger dependence on the inner cylinder rotating speed. (2) The heat transfer coefficient at the top of the labyrinth was about three times as large as that at the bottom. (3) An empirical correlation equation considering the gap between the inner and outer cylinders is proposed, which predicts the heat transfer coefficient on the rotating machine within ±30 percent. © 1997 Scripta Technica. Inc. Heat Trans Jpn Res. 25 (2): 103–119, 1996     

Cooling characteristics of an impinging spray jet which forms an ellipsoidal liquid film

The cooling characteristics of an impinging spray jet which forms an ellipsoidal liquid film were experimentally investigated in order to estimate the cooling performance of a rotating roll in a hot mill system. The following four conclusions were reached in the study. (1) In the case of a single spray jet, the local heat transfer coefficient at the center position depends on the forced convective heat transfer by the impinging jet. However, the average heat transfer coefficient is proportional to the flow rate density of the cooling water, and it does not depend on the distance between the nozzle and heated surface. (2) In the case of a double spray jet, liquid film interference occurs. The local heat transfer coefficient at the center position is greater, and the cooling performance increases with the increasing flow rate density of the cooling water. (3) The cooling performance of a multispray jet is proportional to the flow rate density of the cooling water. It does not depend on the nozzle construction, distance, or specifications. Also, there is no relation to the liquid film interference. (4) When the optimum specifications of the spray nozzle are used, thermal analysis of a rotating roll shows that the temperature at a depth of 1.3 mm from the surface is below 130 °C. © 2000 Scripta Technica, Heat Trans Asian Res, 29(4): 280–299, 2000     

A Natural Bone Cement—A Laboratory Novelty Led to the Development of Revolutionary New Biomaterials

Research on calcium phosphate chemistry at NIST led to the discovery of the worlds first self-hardening calcium phosphate cements (CPC) in 1987. Laboratory, animal, and clinical studies were conducted to develop CPC into clinically useful biomaterials. The combination of self-hardening capability and high biocompatibility makes CPC a unique material for repairing bone defects. Near perfect adaptation of the cement to the tissue surfaces in a defect, and a gradual resorption followed by new bone formation are some of the other distinctive advantages of this biomaterial. In 1996 a CPC, consisting of tetracalcium phosphate and dicalcium phosphate anhydrous, was approved by the Food and Drug Administration (FDA) for repairing cranial defects in humans, thus becoming the first material of its kind available for clinical use. This paper will review the course of the development, the physical and chemical properties, and clinical applications of CPC.     

Effects of material strain rate sensitivity in low speed impact between two identical spheres

This paper investigates the effects of strain rate sensitivity on the impact of two identical spheres. The spheres made of SUJ2 steel were impacted by using pendulum setup. The coefficients of restitution (COR) and contact durations were obtained experimentally. Static tensile test and Split Hopkinson pressure bar tests were conducted to identify the material properties of the sphere. And finite element simulations of the impacts between two identical spheres were carried out using LS-DYNA software. The simulation results fit well to the experimental results and they were compared to the results of elasto-plastic simulations which ignored the material strain rate sensitivity. It was found that the strain rate sensitive sphere showed the higher COR than those from the sphere which ignored the material strain rate sensitivity. Therefore, the material strain rate sensitivity has remarkable effect on the impact of two identical spheres even in the low speed impact. However, the influences of the material strain rate sensitivity on the contact durations were small.     

Pyroelectric infrared detector for precision earth sensor

Two new types of infrared detectors have been developed for the precision earth sensor in the three axis stabilized satellite, Engineering Test Satellite VI (ETS-VI). Both detectors have a pair of infrared sensing elements, each of which is made of a pyroelectric material and mounted on an immersion lens. A-type element is a flake of lead titanate ceramic, and B-type is a sputtered epitaxial film of calcium-modified lead titanate. The precision earth sensor consists of a scanning mirror and an infrared telescope containing an objective lens, plus either type of infrared detector. Detectivity of each type at 120Hz, which is the nominal frequency of the earth sensor's signal, is 1.5×10⁹Hz^1/2/W(A-type) and 2.7×10⁹Hz^1/2/W(B-type) at 14～16.25μm. Each value is 2.5 and 4.5 times as high as the previous model in ETS-V. A-type detector passed the space environmental test and the random error cf attitude measurement was 0.03 deg with the preliminary model of the earth sensor being ahead of the breadboard model. This measurement accuracy is nearly equal to that of the foremost earth sensor. A-type was chosen as the detector for ETS-VI. The random error of the earth sensor with B-type detector is 0.012deg, smaller than a half of the A-type sensor's error. Investigation of B-type is being continued in order to confirm its reliability for space use.     

Expansion of a static analysis-based out-of-plane maximum inelastic seismic response estimation method for steel arch bridges to in-plane response estimation

We have previously proposed a static analysis-based method for estimating the maximum out-of-plane inelastic seismic response of upper-deck steel arch bridges. The method is developed on the basis of the numerical examinations of 6 upper-deck steel arch bridge models. It employs free vibration analysis, response spectrum method and equal energy assumption for the estimation of maximum out-of-plane response. Correction functions are proposed to modify the estimates by the equal energy assumption. In the current study, applicability of the same procedure to the estimation of maximum in-plane response is discussed. It is found that the method can be used also for the maximum in-plane response estimation by only modifying the pushover analysis procedure. The validity of the method is demonstrated for the same parametric models through further numerical evaluations.