Preparation of PZT Microtubes by Slip Casting on Vermicelli,Followed by In Situ Polymerization

Slip casting of lead zirconate titanate (PZT) slurries of higher solids loading (48.8–51.6 vol%) prepared in a urea–formaldehyde (UF) monomer solution on vermicelli of ∼1000 μm diameter has been studied to prepare PZT microtubes with a higher wall thickness (200–960 μm) in a lower dipping time (0.5–4.0 min) to facilitate faster production and lower failure during drying and vermicelli burnout. Polymerization of the UF monomer by exposing the PZT slurry-coated vermicelli to HCl gas provides good strength and stability to the coating. The dielectric and piezoelectric properties of the microtubes compare well with the properties of PZT-5H ceramic compositions.     

AI and computer-based methods in performance evaluation of sporting feats: an overview

Performance evaluation is a complex process, usually involving the analyses of large amounts of possibly subjective information. The complexity increases when the performances of more than one athlete are being evaluated. For example a coach in charge of twenty divers should be able to remember the strengths and weaknesses of each athlete. Given these difficulties, it is therefore not surprising that a number of computer-based systems have been developed to speed-up and improve the quality of performance evaluation. Most of these systems are visually based such that individuals working on performance analysis first record the motion in question by electronic means and then input these images into a computer for quantification and subsequent analysis. There seems to be enormous potential for AI (i.e. Artificial Intelligence) technologies to make a significant contribution in the analysis phase. Indeed AI technologies have been applied to performance evaluation in recent years, though their applicability has been limited for a variety of reasons. The main factor has been a lack of characterisation of the domain of performance evaluation. This paper reviews selected research and applications of computational models and AI technologies in particular in performance evaluation of sporting feats for individual based events.     

ARMS — Application of AI and OR Methods to Resource Management

This paper documents work on automating resource management in BT Retail. BT Retail manages BT's access network and provides telecommunications services to its customers. BT Retail's field engineers are allocated jobs via an information system known as Work Manager. In order to proactively position the engineers (i.e. resources) so as to service jobs in an optimal manner resource managers are involved in analysing the profiles of engineers in the light of incoming jobs and ‘selecting’ those profiles that will yield best quality of service (QoS) and reduce operational costs. A profile is a set of attributes that define a resource's capabilities (i.e. skills), capacity (i.e. availability), and location (i.e. area). Resource planning involves identifying an ‘optimal’ set of resource profiles. Accurate workload forecasting is sine qua non for optimal resource planning. To this end we have developed ARMS, Automated Resource Management System, a suite of components for workload forecasting and resource planning. This revised version was published online in July 2006 with corrections to the Cover Date.     

ARMS Collaborator — Intelligent Agents Using Markets to Organise Resourcing in Modern Enterprises

An efficient deployment of the BT workforce in response to the dynamic nature of customer requests for services is crucial to BT's ability to compete in the ever-competitive telecommunications markets. The Automated Resource Management System (ARMS) is being developed to tackle this challenging problem. Its aim is to efficiently utilise the BT workforce by intelligently assigning engineers in line with forecast and real jobs. ARMS has three major functional components — Forecasting and Job Generation (FJG), Dynamic Planner (DP) and Collaborator. This paper is based on Collaborator — a computer system responsible for monitoring and supporting resource re-distribution decision-making in BT's operational resource management units. Collaborator enhances the deployment process by allowing dynamic re-distribution of engineers among a group of customer service teams (CSTs) so that resource utilisation is improved. Collaborator focuses on balancing the workforce across multiple patches. Collaborator is formulated as a multi-agent coordination problem. Various software agents support the manager's decision-making process. BT aims to further optimise resource deployment by using this novel approach, and ultimately to substantially reduce its operational costs. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antimicrobial interactions of microbial species involved in the fermentation of cassava dough into agbelima with particular reference to the inhibitory effect of lactic acid bacteria on enteric pathogens

Lactic acid bacteria, Bacillus species and yeasts are involved in the fermentation of cassava dough into agbelima. Microbial interactions within and between these groups of microorganisms were investigated in addition to the survival of five enteric pathogens inoculated into agbelima under various conditions. Nine out of 10 cultures of lactic acid bacteria isolated at the end of agbelima fermentation showed inhibitory effect against 10 cultures of lactic acid bacteria isolated at the start of fermentation. Only 3 out of 10 isolates of Bacillus subtilis were inhibited by 10 isolates of lactic acid bacteria tested. No interactions were observed between yeasts and the lactic acid bacteria, whereas three of the Bacillus isolates showed inhibitory effects against the yeasts. Twelve isolates of Lactobacillus plantarum tested inhibited the growth of an isolate each of Lactobacillus fermentum and Lactobacillus brevis but none tested positive for bacteriocin production. The antimicrobial effect of the lactic acid bacteria was attributed to acid production. In fermenting cassava dough, enteric pathogens survived to different extents depending on pH and their sensitivity to acids. Vibrio cholerae C-230, Salmonella typhimurium 9 and Salmonella enteritidis 226 were not detectable in 10 g of sample after 4 h when inoculated into the 48-h fermented product, agbelima, whereas Shigella dysenteriae 2357T and Escherichia coli D2188 were detectable up to 8 h in the product.     

Textural and hydrogen sulphide adsorption behaviour of double metal–silica modified with potassium permanganate

A new MgCa–silica material with bimodal pore size is impregnated with KMnO₄ for dynamic adsorption of H₂S. The MgCa–silica was synthesized using sodium silicate and calcium and magnesium salts as precipitating agents. The KMnO₄ impregnation onto MgCa–silica was obtained through either direct addition into MgCa–silica wet coagulum or doping of dried MgCa–silica pellets into KMnO₄ solution. These chemisorbents were characterized by nitrogen physisorption, spectrophotometer, microscopy and dynamic H₂S adsorption test setup similar to ASHRAE standard I45.I. The results show that impregnation route and KMnO₄ wt% cause a reduction of surface area and total pore volume. The decrease in pore volume was slightly more in chemisorbents obtained via post doping compared to direct impregnation. Regardless of pore volume reduction the pore size range, 1–32 nm, was as in the parent MgCa–silica with micro and meso-pore diameter centered at 1.4 and 5.4 nm respectively. Thus obtained chemisorbents have their pore entrances neither blocked nor shifted. The MgCa–silica/KMnO₄ chemisorbents exhibits good H₂S uptake performance. The chemisorbent with 11.4 wt% KMnO₄ and obtained via direct impregnation possesses the highest uptake capacity. The lowest capacity was observed for chemisorbent with 8 wt% KMnO₄ and made by direct impregnation. The variations in uptake capacity are likely due to impregnation route, the KMnO₄ content and its location in the pore system. The results suggest that the MgCa–silica/KMnO₄ chemisorbents can remove H₂S from indoor air at room temperature.     

Response of Pteromalus cerealellae to conspecific odor: Evidence for female- and male-produced pheromones?

Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) is an ectoparasitoid of several pests of stored products. We investigated the role of semiochemicals in mediating intraspecific communication in this parasitoid using electroantennogram (EAG) and behavioral bioassays. Responses of virgin male and female P. cerealellae were tested to airborne volatiles from live male and female conspecifics and to whole body extracts of both sexes. Females showed significantly greater EAG responses than males to whole body extracts of both sexes. Results from Y-tube olfactometer bioassays demonstrated significant attraction of both sexes to live conspecifics of the same (intrasexual attraction) or opposite sex (cross attraction). Females also showed significant attraction to whole body extracts of females, but not to the extract of males. These findings provide preliminary evidence for possible existence of a female-produced sex pheromone and close range cuticular chemicals by both sexes of P. cerealellae, which may play a role in courtship and species recognition. Further studies are needed to characterize these chemicals and determine their roles in the behavioral ecology of P. cerealellae.     

Effect of gas-phase transport in a planar solid oxide fuel cell

Reaction mechanisms and performance improvement in solid oxide fuel cells (SOFCs) have been the major research areas in this field. There are several discrepancies associated with the kinetics of SOFCs due to the contradicting theories proposed by researchers in this area. This work aims at determining the overpotential due to the gas-phase mass transfer resistance at the various electrodes and the possible electrode reaction characteristics using the inert gas step addition (ISA) method proposed by this research group. The ISA method can quantitatively measure the overpotentials due to the mass transfer resistance at each electrode. The ISA method shows an inverse relationship between the overpotential shift and the square root of the reactant gas flow rate according to the boundary layer theory. The overpotential due to the gas-phase mass transfer resistance is expected to be much higher at the anode than at the cathode, indicating the presence of considerable gas-phase mass transfer resistance at the anode.     

Changes in evaporative emissions from gasoline in the Nigeria market

The evaporative emissions from multicomponent fuel are expected to change significantly with the progress of evaporation. This study presents the findings of air emission associated with changes (increase) in evaporation process of gasoline. The parameters measured in the experiment included the weight loss, density, viscosity of gasoline, and the evaporation rate. Results showed that the parameters changed significantly as evaporation progressed. The weight loss was from 3.02% to 5.45% after 30 m and presented a logarithmic curve with time. The density measurements of the gasoline samples were 728.5–746.7 kg/m³. The evaporation rate which was 1.22 × 10^?5–2.14 × 10^?5 kg/s showed great increase with decrease in density and kinematic viscosity at ambient temperature with sample C (from Lagos) having the highest evaporation rate. The emission rate was observed to be inversely proportional to the sample density. Most of the changes might be attributed to the air emission of volatile hydrocarbons such as benzene, toluene, ethyl benzene, and xylene (BTEX) from gasoline surface to the environment.