Effect of strain waveform on creep-fatigue life for Sn–8Zn–3Bi solder

This paper describes the creep‐fatigue life of Sn–8Zn–3Bi under push–pull loading. Creep‐fatigue tests were carried out using Sn–8Zn–3Bi specimens in fast–fast, fast–slow, slow–fast, slow–slow and hold–time strain waveforms. Creep‐fatigue lives in the slow–slow and hold‐time waveforms showed a small reduction from the fast–fast lives but those in the slow–fast and fast–slow waveforms showed a significant reduction from the fast–fast lives. Conventional creep‐fatigue life prediction methods were applied to the experimental data and the applicability of the methods was discussed. Creep‐fatigue characteristics of Sn–8Zn–3Bi were compared with those of Sn–3.5Ag and Sn–37Pb.     

Prototype Experiments on a 1/32‐Scale Model Via‐Wheel Power Transfer Electric Vehicle

Electric vehicles (EVs) are expected to play a leading role in the changeover from fossil fuels to clean energy. However, EVs are currently not very popular, owing to their short cruising distance and long charging time. Wireless power transfer from the infrastructure to running EVs is expected to be the solution to these problems. Electric vehicle and electrified roadway (EVER) has been proposed as a wireless power transfer system for EVs while in motion. Via‐wheel power transfer (V‐WPT) is expected to be a wireless power transfer scheme for EVER. We designed and prototyped a 1:32 scale model of a V‐WPT system that consists of an RF inverter, an electrified roadway, a rectifier, and an EV with a dc motor. The output power of the prototype RF inverter was 5.9 W and the dc–RF conversion efficiency was 36.6%. The LC matching circuits for the V‐WPT were designed with two‐port conjugate matching because S₁₁ of the V‐WPT was intrinsically –0.06 dB. After matching, the S₁₁ value was reduced to –21.5 dB. The power transmission efficiency of the V‐WPT system was 75%. The RF–dc conversion efficiency of the rectifier was 62%. The total efficiency of the EVER system was 24.2%.     

Electrical Resistivity of Titanium-Containing Glasses

Titanium-containing glasses were prepared by fusion of a base glass (BaO·B₂O₃SiO₂) and TiO₂ and/or Ti₂O₃ in Ar. Their resistivities did not vary with melting time and temperature. Interaction of Ti⁴⁺ and Ti³⁺ in the glasses was deduced by spectroscopy, but the valence states in the batch compositions were preserved in the glasses, according to the chemical analysis. Glasses containing either Ti⁴⁺ or Ti³⁺ had very high resistivities, whereas the glass prepared by melting a mixture of a Ti⁴⁺-containing and a Ti³⁺-containing glass had much lower resistivity. All results confirmed the possibility of controlling the resistivity by batch composition for these glasses.     

Detection of Chemiluminescence Produced during Beer Oxidation

Chemiluminescence (CL) produced in beer was detected using the single photoelectron counting system. CL production did not occur in a nitrogen atmosphere but did occur in air and was dependent on incubation temperatures. It was inhibited by the addition of ascorbic acid. CL analysis should provide useful information in the study of oxidative deterioration of beer.     

Fluorometric Peroxygenase Assay for Lipid Hydroperoxides in Meats and Fish

A fluorometric assay for lipid hydroperoxide in meats and fish was developed using pea peroxygenase, a hydroperoxide-dependent hy-droxylase. The freeze-dried microsome fraction of germinating pea seed was used as a peroxygenase source. Linear relationships between the hydroperoxide added (25 to 150 nmol) and fluorescence were observed with methyl linoleate hydroperoxide, linoleic acid hydroperoxide, triglyceride hydroperoxide, and phosphatidylcholine hydroperoxide. α-Tocopherol at levels equivalent to those in meats and fish did not affect the peroxygenase reaction. The assay was specific for hydroperoxides. The method enables determination of total lipid hy droperoxides in sample homogenates without extracting total lipids from retail meats and fish.     

Mixing and Flow Characteristics in the Alumina/Thermoplastic Resin System

Rheological properties were investigated for combinations of six different alumina and three thermoplastic resins of polyethylene, polypropylene, and polystyrene. The curves of torque versus time in the alumina/resin mixture systems could be classified into four patterns depending on both the mixing properties of each of the resins and the solid concentration. It was verified through infrared spectroscopy and gel permeation chromatography measurements that the behavior of the mixtures could be explained by taking the degradation of each resin into account. Flow was characterized as shear thinning in both the alumina/resin and resin systems. A simple parameter, V¯_p= (ρ_cr− V¯)/ρ_cr, a kind of corrected liquid volume concentration, was introduced to express the dependence of relative viscosity η_r of the mixture on the solid concentration V¯ and the relative compaction density ρ_cr. The relation η_r=αV¯^−β_p could be useful for estimation of the flow properties of ceramic powder/resin mixture systems.     

Scattering Study of Microstructurally Birefringent Glasses

Microstructurally birefringent, phase-separated borosilicate glasses were investigated by X-ray small-angle scattering and light scattering. X-ray small-angle scattering data confirmed the presence of ellipsoidal particles and the light-scattering data indicated the presence of anisotropic distribution of particles. These observations support the previous contention that the positive birefringence is due to the form birefringence and the negative birefringence is due to the anisotropic distribution of spherical particles.     

Effect of Phase Separation on HF Etch Rate of Borosilicate Glasses

Etch rates of borosilicate glasses in HF were studied as a function of heat-treatment time and temperature for liquid-in-liquid phase separation. It is shown that, when the phase-separated glass has an interconnected microstructure, the composition of the chemically less durable phase is the dominant factor in HF durability. When the phase-separated glass has a dispersed alkali-borate-rich (chemically less durable) phase embedded in a silica-rich matrix, the HF etch rate is constant, independent of the extent of phase separation.     

Sodium Transport in the Na2O-H2O-SiO2 Glass System

The variation with water content of dc conductivity and Na diffusion coefficient for the Na₂O · 4siO₂ and Na₂O · 2SiO₂ glass systems was found to be similar to that of the Na₂O.3SiO₂ series reported earlier. The conductivity was estimated for the ternary system Na₂O-H₂O-SiO₂ by combining the present results with the previous data on the Na₂O · 3SiO₂ system. When the conductivity of those glasses with a constant [Na₂O] + [H₂O] content was plotted against water content, a pronounced mixed "alkali" effect was demonstrated. The Haven ratio, calculated by comparison of the dc conductivity to the Na diffusion coefficient at 100°C for each of the three glass systems, was found to increase toward unity with increasing water content. This suggests that the addition of water reduces the number of sodium charge carriers. The subsequent increase in conductivity beyond the minimum with the introduction of larger amounts of water is, probably, due to an increase in the mobility of the Na⁺ ions.