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The stability constant for Tc(IV)/EDTA complexes were determined using a solvent extraction technique at varying ionic strength (NaCl) and the specific ion interaction theory model allowed for calculating stability constants at zero ionic strength. The stability constants at zero ionic strength for the formation of the TcOEDTA2− and TcOHEDTA− complexes are 1020.0 ± 0.4 and 1025.3 ± 0.5, respectively. The modeled Tc(IV) solubility was calculated to be 3.9 × 10−7 M at near-neutral pH and in presence of 2.5 mM EDTA, a result found to be in good agreement with published solubility experimental data. Speciation calculations showed that TcOEDTA2− is the predominant species between pH 4 and 7.5 in presence of 0.171 mM EDTA, while TcO(OH)2 0 is predominant in basic solution. These studies show that EDTA has a very strong affinity for complexation with Tc(IV) and can increase the environmental mobility of Tc(IV).

Vertical arrays of one-dimensional tin nanowires on silicon dioxide (SiO2)/silicon (Si) substrates have been developed as anode materials for lithium rechargeable microbatteries. The process is complementary metal-oxide-semiconductor (CMOS) compatible for fabricating on-chip microbatteries. Nanoporous anodized aluminum oxide (AAO) templates integrated on SiO2/Si substrates were employed for fabrication of tin nanowires resulting in high surface area of anodes. The microstructure of these nanowire arrays was investigated by scanning electron microscopy and X-ray diffraction. The electrochemical tests showed that the discharge capacity of about 400 mA h g−1 could be maintained after 15 cycles at the high discharge/charge rate of 4200 mA g−1. Keywords: Lithium microbattery, Anode material, Tin nanowire, Anodized aluminum oxide

This study aims at predicting Carbon monoxide (CO) emission rate as well as carboxyhaemoglobin (HbCO) levelsin Al-Ain City, United Arab Emirates (UAE). Also, several mathematical models are proposed for estimating both CO emission and HbCO levels. These models yield excellent agreements between observed and predicted data and can be easily coupled with atmospheric models. Carbon monoxide exposure from motor vehicles were measured over a 3-month period from September to December 1995 at three locations in the UAE. The study is based on a sample of 148 cars. The data revealed that the major characteristics of the cars surveyed were as follows: 69.5% of the cars were Japanese, 74.3% of the cars were 5 years old; 41% of the car was range rover or four-wheel-drive car, which indicates a higher proportion of powerful cars; 58.8% was used special fuel; 51.4% had regular maintenance for their cars and 52% of the cars had 4 cylinder engine capacity. Carboxyhaemoglobin (HbCO) levels in the UAE were predicted for 1-hour (1.720 ppm) and 8-hour (8.106 ppm) exposure times. Also, on an average driving of 80 km hr−1 per day, the CO emission rate was found to be 8.729 ppm. These findings indicate that the mean 1-hour and 8-hour Carboxyhaemoglobin (HbCO) levels do not exceed the permissible standards recommended by the WHO. Additionally, the results of stepwise multiple regression analyses revealed that the factors, such as, type of car, size of cylinder, size of car, and maintaining service of the car exerted the greatest influence on the amount and concentration of pollutant emission produced by car exhaust.

Gas-phase mixing and dispersion in a typical commercial-scale diffusion furnace was investigated using computational fluid dynamic simulations and experimentation. Five regions were defined within the furnace: (i) entrance volume, (ii) annular volume around the wafer-source stack, (iii) radial volumes between wafer-source pairs, (iv) intermediate volumes between successive wafer carriers, and (v) exit volume. The mixing characteristics within each of these volumes was quantified and appropriate mixing models were defined based on the relative amount of backmixing or gas exchange within and between these volumes. A dispersion-based approach was then used to develop a simplified model describing the transient transport of water vapor (H 2 O) during a typical hydrogen injection cycle. Model parameters were calibrated using experimental data from tracer impulse studies.