A new service provisioning method in the multimedia/B-ISDN era

In the coming multimedia/B-ISDN era, customers must be able to design, define, and manage communication services based on their own concepts and knowledge of communications. This article proposes a new concept, intelligent dynamic service provisioning (IDSP), offering customers this capability. Service views of customers and carriers for multimedia services are presented. Based on these views, we propose an architecture for the IDSP system. Finally, the basic mechanism of the IDSP system and the technical issues related to this system are examined     

Photogalvanic effect of thin-layer photocells composed of thionine/Fe(II) systems

Photoredox reactions and photogalvanic effects of gel-systems containing thionine, Fe(II) salt and gelatinizing agents were studied by using a thin-layer photocell, the electrodes of which were SnO₂ and Pt. The photopotential and photocurrent of a gel-system depended on the characteristics of the gelatinizing agent; the values were large and did not decay with illumination time when the gelatinizing agent had intramacromolecular hydrogen bonds. The reason of large values and of good electron-recycling inside the cell was presumably owing to the hydrogen-transfer type electron-exchange reaction between Fe(III) and Fe(II), which proceeded the electron-recycling inside the cell. As the intra-macromolecular hydrogen bonds accelerated the electron-exchange reaction, it was concluded that the primary structure of the gelatinizing agent was the most important factor determining the frequency of the electron-exchange reaction.     

Synthesis of polymerizable glycerophosphocholines and their polymerized vesicles

Summary Three types of polymerizable glycerophosphocholines have been prepared. They have a styrene group through a spacer having a ketone, ether or amide group. The ketone-and ether-type compounds form nonpolymerized and polymerized vesicles depending on the chain length of the alkyl group at the 2-position of glycerol. The polymerized vesicles are stable for months.     

Potentiometric studies on the adsorption of Au(CN)2 and Ag(CN)2 onto activated carbon

The adsorption of Au(CN) ₂ ⁻ and Ag(CN) ₂ ⁻ onto activated carbon has been correlated with potential measurements of carbon. It is proposed that Au(CN) ₂ ⁻ , Ag(CN) ₂ ⁻ , and CN⁻ are adsorbed on carbon by both an ion exchange mechanism and an oxidative reaction which leads to a decrease in carbon potential. The potential of carbon decreased according to the degree of anion adsorption in the order Au(CN) ₂ ⁻ > Ag(CN) ₂ ⁻ > CN⁻ > I⁻ > Cl⁻. Adsorption of anions is accompanied by release of OH⁻ ion which raises the solution pH and decreases the carbon potential. The potential of carbon in contact with solutions containing KAu(CN)₂, KAg(CN)₂, or KCN is much more negative than that in contact with chloride solution at the same pH. The results indicate that cyanide is oxidized on the carbon surface by oxygen or by reducible functional groups such as quinone. N. TSUCHIDA, formerly Postgraduate Student, Murdoch University, is Metallurgist with Beshi Nickel Refinery (Sumitomo Metal and Mining Co.), Niihama, Japan     

Estimation of In-Situ Shear Strength Parameters of Weathered Granitic (MASADO) Slopes Using Lightweight Dynamic Cone Penetrometer

A major problem in the geotechnical approach to the stability of natural slopes is that there is usually little information on the in-situ geotechnical conditions, because of the extreme difficulty associated with ground investigations of steep slopes covered with vegetation. In this study, a lightweight dynamic cone penetration test (LWDCPT) has been introduced for a geotechnical survey of natural weathered granitic (Masado) slopes. Based on a series of direct shear tests, the internal friction angle and the apparent cohesion of reconstituted Masado soil were found to be fairly closely related to the void ratio and the degree of saturation in the soil. From the laboratory calibration tests, an equation was created to relate the dynamic cone resistance (q_d) and the void ratio of reconstituted Masado under different degrees of saturation. Equations were developed to calculate the internal friction angle and the apparent cohesion from the value of q_d for Masado at a known degree of saturation. LWDCPT and direct shear tests were carried out on undisturbed samples taken from a natural Masado slope. The estimated internal friction angle and the apparent cohesion calculated with the value of q_d in the LWDCPTs agreed fairly well with those of tests on the undisturbed samples obtained in laboratory shear tests.     

Synthesis and thermal characteristics of poly(thioarylene)s by thermal polymerization

Thermal polymerization of bis[4-(4-bromophenylthio)phenyl] disulfide (I), bis[4-(4-bromophenyloxy)phenyl] disulfide (II) and bis[(4-(4-bromophenylsulfony)phenyloxy)phenyl] disulfide (III) was carried out at 250°C in diphenyl ether. The resulting poly(thioarylene)s show high crystallinity and high thermal stability. The blends and copolymers of poly(thioarylene) were also prepared, whose thermal properties were investigated by DSC measurements.     

Stochastic Modeling of a New Spectrometer

A new spectrometer for classifying aerosol particles according to specific masses is being considered (Ehara et al. 1995). The spectrometer consists of concentric cylinders which rotate. The instrument is designed so that an electric field is established between the cylinders. Thus, aerosol particles injected into the spectrometer are subjected to a centrifugal force and an electric force. Depending on the balance between these two forces, as well as Brownian motion, charged particles either pass through the space between the cylinders or stick to either cylinder wall. Particles which pass through are detected. Given the rotation rate, voltage drop and physical dimensions of the device, we calculate the probability of detection in terms of particle density, diameter and charge. This is the transfer function. In this work, the focus is on situations where Brownian motion is significant. To solve for the transfer function, the trajectory of a particle in the spectrometer is modeled with a stochastic differential equation. Laminar flow is assumed. Further, attention is restricted to spherical particles with uniform density. The equation is solved using both numerical and Monte Carlo methods. The agreement between methods is excellent.