The Ergonomics Society--the Society Lectures 1999: the Ergonomics Society: 50 years of growth

Developments in the Society are outlined since the early history was described by Edholm and Murrell. Major changes in the Society's operation and the context in which these changes took place are given. The changes in research directions, growth in educational facilities for professional education and the ever widening areas for the application of ergonomics are discussed. The consequences of these developments for the expansion of a recognition of the contribution of ergonomics, and the position of professionals in the international scene are touched upon.     

Photolytic (UVC) and photocatalyic (UVC/TiO2) decomposition of pyridines

The degradation of 2-chloropyridine (2-CPY) and its degradation primary product 2-hydroxypyridine (2-HPY) was studied by means of ultraviolet (UV) irradiation at 254nm. Photolytic and photocatalytic experiments were conducted on 2-CPY and 2-HPY aqueous solutions in a batch reactor with internal recycle in laminar and turbulent conditions at 50 degrees C in a closed but not airtight system with and without additional aeration, at solution ambient pH and at controlled pH conditions, with use and in the absence of radical scavenger. The solution volume was 0.4L and initial substrate concentrations were approximately 2.6mmol/L (0.25-0.3g/L depending on the substrate). Where applicable 1g/L TiO(2) (P-25) was used, suspended in the liquid in a form of turbulent slurry or using a glass tube around the UV-lamp on which a fixed TiO(2) catalytic layer had been deposited. At the aforementioned conditions 2-CPY readily degrades photolytically, the catalytic path having very little influence. In all cases 2-CPY produces 2-HPY which further degrades to other products. Aeration, pH and the presence of catalyst and/or radical scavengers do not affect the rate of decomposition of 2-CPY, but have a strong influence on the further decomposition of the produced 2-HPY. 2-HPY decomposition proceeds both catalytically and photolytically following oxygen dependent and oxygen independent pathways.     

Higher risk taking propensity of contact lens wearers is associated with less compliance

Purpose

To determine whether risk taking personality is associated with compliance in contact lens wear, and how practitioner perception of compliance compares with wearer risk taking and non-compliant behaviour.

Method

Optometrists in Australia, recruited through professional organizations, were asked to enroll up to 10 current contact lens wearers each. Wearers completed a questionnaire assessing risk-taking propensity (20-item instrument), non-compliant behaviour and demographics. Non-compliance was scored on four components (maximum score 40, lens disinfection, 20; hand hygiene, 8; case hygiene, 6; case replacement, 6). Independently, practitioners ranked each wearer's non-compliance on a 1–5 scale. Associations between wearer risk taking propensity, non-compliant behaviour and practitioner perceived non-compliance were investigated using Pearson correlation. Significant associations were entered into a linear regression model predicting overall non-compliant behaviour.

Results

Seventy-three wearers were recruited by 18 optometrists (mean 4, range 1–10). Wearer risk taking was associated with less compliance (p < 0.01) as was younger age (p < 0.01) and male gender (p = 0.02). Years of lens wear was not associated with non-compliant behaviour (p = 0.8), nor was practitioner perception of compliance (p > 0.6) Linear regression indicated that risk taking was the only independent significant factor predicting non-compliance, explaining 24% of the variation in behaviour.

Conclusion

A higher risk taking personality style of contact lens wearers in Australia is associated with less compliant behaviour. Risk taking is a better predictor of compliance than age, gender and practitioner perception and helps explain the individual characteristics of wearers that may influence lens care and maintenance.     

Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.     

Low-Complexity Load Balancing with a Self-Organized Intelligent Distributed Antenna System

A high call blocking rate is a consequence of an inefficient utilization of system resources, which is often caused by a load imbalance in the network. Load imbalances are common in wireless networks with a large number of cellular users. This paper investigates a load-balancing scheme for mobile networks that optimizes cellular performance with constraints of physical resource limits and users quality of service demands. In order to efficiently utilize the system resources, an intelligent distributed antenna system (IDAS) fed by a multi base transceiver station (BTS) has the ability to distribute the system resources over a given geographic area. To enable load balancing among distributed antenna modules we dynamically allocate the remote antenna modules to the BTSs using an intelligent algorithm. A self-optimizing network for an IDAS is formulated as an integer based linear constrained optimization problem, which tries to balance the load among the BTSs. A discrete particle swarm optimization (DPSO) algorithm as an evolutionary algorithm is proposed to solve the optimization problem. The computational results of the DPSO algorithm demonstrate optimum performance for small-scale networks and near-optimum performance for large-scale networks. The DPSO algorithm is faster with marginally less complexity than an exhaustive search algorithm.