Characteristics of humic substances in the Kuji River waters as determined by high-performance size exclusion chromatography with fluorescence detection

Direct measurement by high-performance size exclusion chromatography with fluorescence detection was applied to the characterization of humic substances in river waters from the Kuji River system, which runs through forest hills and an agricultural plain in Japan. The monitoring wavelength of excitation 320 nm and emission 430 nm corresponds to the fluorescence maxima for aquatic fulvic acid. Chromatograms of the river waters showed four peaks; each peak position was in good agreement among these samples. Peak height ratios for the samples from the upstream Kuji River and its tributaries were different from those of the midstream and downstream sections of the Kuji River, which may reflect differences in the characteristics of humic substances and other organic materials supplied from soil to river.     

Dynamic analysis of reinforced concrete frame-wall structures

The nonlinear response and failure mechanism of reinforced concrete frame-wall systems is investigated through the employment of a mathematical model. The mathematical model is composed of two mechanical models: a concentrated spring model used for the flexural behaviour of beam and column type members and a multiple spring model used for the response of the wall system. Both account for inelastic behaviour of reinforced concrete.The mathematical model is applied to a ten-storey frame-wall system. The constituent members are replaced by one of the mechanical models whose stiffness characteristics reflect the inelastic properties and hysteresis tendencies of the member. The resulting equations are solved by a step by step time integration procedure. Computed results are compared with experimental results obtained from a structure tested on the Illinois earthquake simulator. The correlated results are then used to define the significant response characteristics.     

Calcium phosphates formation on CaTiO<Subscript>3</Subscript> coated titanium

In this study, performance of calcium phosphate formation of CaTiO₃ coating film on Ti in Hanks’ balanced saline solution (HBSS) was investigated. CaTiO₃ thin films with a thickness of 50 nm were deposited on Ti using radiofrequency (RF) magnetron sputtering. The temperature of Ti substrate was adjusted to room temperature (RT) and 873 K. Thereafter, the specimens deposited at RT were annealed at 873 K in air for 7.2 ks. The films were characterized by grazing incident angle X-ray diffractometry (GI-XRD) and X-ray photoelectron spectroscopy (XPS). After immersion in HBSS for 60 d, on CaTiO₃ coated Ti, the formation of hydroxyapatite (HAP) was observed. Furthermore, HAP layer formed was thicker on the specimen on which CaTiO₃ film was deposited at RT and annealed than that prepared at 873 K. The major difference between both specimens was the chemical properties of the outermost surface. In summary, CaTiO₃ thin film deposited at RT and followed by annealing at 873 K for 7.2 ks in air enhances calcium phosphate formation ability on Ti.     

Long-chain polyamines (LCPAs) from marine sponge: possible implication in spicule formation

Two distinct marine organisms, diatoms and sponges, deposit dissolved silicates to construct highly architectural and species-specific body supports. Several factors such as proteins, long-chain polyamines (LCPAs), or polypeptides modified with LCPAs are known to be involved in this process. The LCPAs contained in the silica walls of diatoms are thought to play pivotal roles in the silica deposition. In sponges, however, a protein called silicatein and several other proteins have been reported to be the factors involved in the silica deposition. However, no other factors involved in this process have been reported. We have identified the LCPAs from the marine sponge Axinyssa aculeata and present here some evidence that sponge-derived LCPAs can deposit silica and that the LCPA derivatives are associated with spicules. The results indicate a common chemistry between sponges and diatoms, the two major players in the biological circulation of silicon in the marine environment. A wide variety of organisms are known to utilize silica in their biological processes. Polyamines or other functional molecules might be involved, in combination with proteins, in their biosilicification process.     

Novel microporous carbon material with flower like structure templated by MCM-22

Novel flower like microporous carbons with very high surface area have been synthesized for the first time using MCM-22 zeolite as a template and sucrose as a carbon source. The textural parameters of the materials can easily be tuned by the simple adjustment of the sucrose to MCM-22 weight ratio. It has been also found that the specific surface area of the microporous carbon materials is much higher as compared with that of its parent zeolite template.     

Toward an information-integrated control system—the control-theoretic view of intelligent control technology

Recent computing technology is providing alternative strategies for the functionality and implementation of controllers for practical complex systems. An important issue will be how to integrate all information about control problems. In this paper, we present the control-theoretic view of intelligent control technology, and discuss a paradigm for an information-integrated control system. This work was presented, in part, at the Third International Symposium on Artificial Life and Robotics, Oita, Japan, January 19–21, 1998     

Characteristic behavior of aluminum-stainless laminated sheet in redrawing

Using a rigid-plastic finite element program deep drawing, direct and reverse redrawing of two layer aluminum-austenitic stainless steel (AL-ASS) laminated sheets have been simulated. The results of simulations as the variation of drawing ratios with thickness ratio and setting condition are presented. They show that to access the highest drawing ratios in direct and reverse redrawing, thickness ratio should be about 1/3 (one layer aluminum and three layer stainless steel) and the setting conditions are opposite to each other. In another word, while in direct redrawing contact of austenitic stainless steel with punch leads to the maximum drawing ratio, in reverse redrawing, aluminum should contact the punch in order to access highest drawing ratio. An explanation for this finding is offered through the thickness strain distribution.     

Numerical simulation of three-dimensional viscoelastic flow within dies

In recent years, the development of CAE (Computer Aided Engineering) in polymer processing has been remarkable, and it is expected to be more realistic in viscoelastic numerical simulation, particularly in three-dimensional complex geometry. Because of the problems of computational memory capacity, CPU time, and the numerical convergence of viscoelastic flow simulation, three-dimensional viscoelastic simulation applicable to industrial flow behaviors has not yet been attempted. In this paper, we developed the numerical simulation of three-dimensional viscoelastic flow within dies using a decoupled method, streamwise integration, and penalty function methods to decrease memory, and the TME (“Transformation of Equation of Motion to the Elliptic Equation,” S. Tanoue, T. Kajiwara, and K. Funatsu, The Eleventh Annual Meeting, the Polymer Processing Society Seoul, Korea, Extended Abstracts p.439) method, which raises the stability of convergence. We confirmed the reliability of this simulation technique to compare simulation results with experimental data of the stress field at a downstream wall shear rate of 5.41s^?1 within a 60° angle tapered contraction die. We compared the predictions of a viscoelastic model (Phan-Thien and Tanner model) with a pure viscosity model (Carreau model) at a downstream wall shear rate of 120s^?1 and discovered a remarkable effect of viscoelasticity in the shear stress and first normal stress difference in particular in the tapered region.