Discharge through a Permeable Rubble Mound Weir

The hydrodynamics of a rubble-mound weir are theoretically and experimentally examined. This type of weir is considered to be environmentally friendly, since its permeability allows substances and aquatic life to pass through longitudinally. By performing a one-dimensional analysis on a steady nonuniform flow through the weir, discharge is described as a function of related parameters, such as flow depths on the up- and downstream sides of the weir, porosity, and grain diameter of the rubble mound, weir length, etc. A laboratory experiment is carried out to determine the empirical coefficients included in the analytical model. The theoretical solution of the discharge is compared with the experimental data to verify the analysis. It is confirmed that agreement between theory and experiment is satisfactory for a wide range of flow conditions. The present study makes it possible to apply the rubble mound weir for practical use as a discharge control system.     

Prediction of the critical heat flux in annular regime in various vertical channels

The axial variation of film flow rate in annular regime was analyzed to predict the critical heat flux in water saturated flow boiling in various vertical channels. In the analyses, several quantities including the deposition and entrainment rates of droplets were evaluated with the correlations that were based on the separate experimental data of film flow rate and droplet flow rate in annular flow; model closure was achieved without introducing arbitrary constants. The predicted results were compared with extensive data of critical heat flux in flow boiling. Fairly good agreements were observed for the critical heat fluxes in round tubes with uniform and axially non-uniform heating and in non-circular shaped channels without sharp corners. It is hence expected that the important processes for the onset of critical heat flux condition in annular regime were satisfactorily described in the model. However, the critical heat fluxes were generally overestimated in thin rectangular channels with sharp corners. The non-uniform distribution of liquid film in channel cross-section would be the primary reason of the disagreement.     

Preparation of hydroxyapatite/collagen injectable bone paste with an anti-washout property utilizing sodium alginate. Part 1: influences of excess supplementation of calcium compounds

The anti-washout property, viscosity, and cytocompatibility to an osteoblastic cell line, MG-63, of anti-washout pastes were investigated. Mixing a hydroxyapatite/collagen bone-like nanocomposite (HAp/Col), an aqueous solution of sodium alginate (Na-Alg), which is a paste hardening and lubricant agent, and supplementation of calcium carbonate or calcium citrate (Ca-Cit) as a calcium resource for the hardening reaction realized an injectable bone paste. Adding Ca-Cit at a concentration greater than eight times the Ca²⁺ ion concentration to Na-Alg improved the anti-washout property. Although the viscosity test indicated a gradual increase in the paste viscosity as the calcium compounds increased, pastes with excess supplementation of calcium compounds exhibited injectability through a syringe with a 1.8?mm inner diameter, realizing an injectable bone filler. Furthermore, the anti-washout pastes with Ca-Cit had almost the same cell proliferation rate as that of the HAp/Col dense body. Therefore, HAp/Col injectable anti-washout pastes composed of the HAp/Col, Na-Alg, and Ca-Cit are potential candidates for bioresorbable bone filler pastes.     

Micro electrochemical machining using electrostatic induction feeding method

This paper describes a micro ECM system using the electrostatic induction feeding method. With this method, since the pulse voltage is coupled to the tool electrode by capacitance, the pulse duration of the electrolytic current is determined by the rise and fall time of the voltage pulse and is thus significantly short, realizing short gap width. A servo feed system was also developed based on the measurement of the gap voltage. Wear of the tungsten tool was negligibly small because of the oxide layer formed on the tool, allowing micro-holes with sharp edges and straight walls to be drilled.     

Neural network‐based PID gain tuning of chemical plant controller

Plant control systems are now highly automated and are used in many industries. The control performance changes with the passage of time because of deterioration of plant facilities. For this reason, human experts tune the control system to improve overall plant performance. In this study, a PID control system for the oil refining chemical plant process is discussed. In oil refining, thousands of control loops are used in plants in order to keep the product quality at the desired value and to assure the safety of plant operation. Due to the ambiguity of the interference between control loops, it is difficult to estimate the plant dynamical model accurately. Using a neuro emulator and a recurrent neural networks model (RNN model) for emulation and tuning of parameters, a PID gain tuning system for a chemical plant controller is constructed. Numerical experiments using actual plant data demonstrate the effect of the proposed method. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(4): 28–36, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20973     

Identification of molecular target of AMP-activated protein kinase activator by affinity purification and mass spectrometry

We show an efficient method to identify molecular targets of small molecular compounds by affinity purification and mass spectrometry. Binding proteins were isolated from target cell lysate using affinity columns, which immobilized the active and inactive compounds. All proteins bound to these affinity columns were eluted by digestion using trypsin and then were identified by mass spectrometry. The specific binding proteins to the active compound, a candidate for molecular targets, were determined by subtracting the identified proteins in an inactive compound-immobilized affinity column from that in an active compound-immobilized affinity column. This method was applied to identification of molecular targets of D942, a furancarboxylic acid derivative, which increases glucose uptake in L6 myocytes through AMP-activated protein kinase (AMPK) activation. To elucidate the mechanism of AMPK activation by D942, affinity columns that immobilized D942 and its inactive derivative, D768, were prepared, and the binding proteins were purified from L6 cell lysate. NAD(P)H dehydrogenase [quinone] 1 (complex I), which was shown as one of the specific binding proteins to D942 by subtracting the binding proteins to D768, was partially inhibited by D942, not D768. Because inhibition of complex I activity led to a decrease in the ATP/AMP ratio, and the change in the ATP/AMP ratio triggered AMPK activation, we identified complex I as a potential protein target of AMPK activation by D942. This result shows our approach can provide crucial information about the molecular targets of small molecular compounds, especially target proteins not yet identified.     

Heat treatment of diamond grains for bonding strength improvement

The heat treatment of synthetic cubo-octahedral diamond grains to produce tight bonding by making their surface rough is reported. In order to obtain a rough surface, a thermal etching technique at atmospheric pressure in air at 700 to 1100°C is applied. The shape, surface features and surface area are investigated, then in order to examine the effect of the roughened diamond surface on bonding strength, peeling and bending tests were carried out. The results obtained showed that: rough surfaces may be obtained by thermal etching at atmospheric pressure in air; on etching at 700 to 1000°C, the etch rate of the {111} face is higher than that of the {100} face, and in particular, diamonds etched at 700 to 1000°C have a hollow {111} face; the surface area of one grain can be increased by etching — on etching at 900°C for 15 min, surfaces become fully covered with clear etch pits and the surface area shows maximum value; the surface area seems to have an influence on bonding strength, and when diamond grains are bonded with phenol resin or electroless plating nickel, bonding strength improves by about 10%.     

Thermal diffusivity of SiO2 and Y2O3 added AIN ceramics

The addition of both SiO₂ and Y₂O₃ to AIN led to decrease of 27R polytype in specimens sintered above 1600° C and also to an increase of thermal diffusivity of AIN ceramics. Furthermore, SiO₂ and Y₂O₃ added AIN ceramics were fully densified by liquid-phase sintering, and resulted in higher thermal diffusivity. The formation temperature of the liquid phase was lowered more by the addition of both SiO₂ and Y₂O₃ than only Y₂O₃ to AIN ceramics.     

The characteristics of McKibben muscle based on the pneumatic experiment system

The electropneumatic regulator is a key device in pneumatic experiment systems which provide compressed gas to McKibben muscles. The electropneumatic regulator structure is analyzed. The stiffness of the McKibben muscle is formulated based on both its force model and the electropneumatic regulator characteristics. The gas pressure transmission process in the whole pneumatic experiment system is investigated. A gas pressure transmission model based on the integrated pneumatic experiment system is established. An experiment is done to prove the model's validity. The results show that the electropneumatic regulator can stabilize its output gas pressure, the inner pressure of McKibben muscle does not vary when its length is changed by an outer force, and there is both a time delay and a rise in gas pressure when compressed air is input to McKibben muscle. The time delay comes from turning on the electropneumatic regulator valve, and the rise in press use corresponds with the filling process of the inner gas pressure in McKibben muscle. This work was presented in part at the 12th International Symposium of Artificial Life and Robotics, Oita, Japan, January 25–27, 2007