Investigation of the driving experience of a sample of Victorian learner drivers

This paper presents the results of an investigation of the driving experience of a small sample of learner drivers in Victoria, Australia. Participants (n = 110) kept a continuous logbook of their driving experience over the 2 years of the learner-driver period, including information about the distance and time of each driving trip, their level of confidence, and monthly data concerning the number of crashes, near misses, and unpleasant emotional interactions with their supervising driver. The analysis of these data suggests that learner drivers accrue relatively little driving experience and that they tend to obtain this experience in daytime, fair-weather driving. The implications of these results are discussed.     

Modelling and optimization of quality and costs on empirical data of hearth bread

Mathematical programming is an optimization technique, which can be used to simultaneously ensure several qualities of a product (cost, chemical composition, product characteristics, etc.). This requires mathematical models for the qualities, and especially different characteristics of a product may be challenging to model. One approach is to make empirical models based on data from experimental designs. In the present paper hearth breads are studied. The protein quality and protein content of the wheat flour have together with the mixing and proving time been found critical for hearth bread characteristics. By adjusting the process settings according to wheat flour properties, hearth breads within acceptable quality limits may be made from very different flours. A mixture-process design was constructed and 99 hearth bread batches were made. Models for hearth bread characteristics and production costs were estimated and optimized by mathematical programming. The study also considers how model uncertainty and different pricing systems of wheat flours and capacity costs influence the optimal solutions.     

Multiscale modelling of human hair

We present a multiscale modelling approach to the mechanics of human hair fibres. On the microscale, a coiled coil of filament proteins was mechanically unfolded in a molecular-dynamics simulation. The force at unfolding was found to be ca. 1 nN, which we estimated to be an order of magnitude above the reversible force. Using the concept of folded/unfolded states, we developed a statistical mechanical model, which predicts a linear decrease of the yield stress with temperature. This was confirmed experimentally by stretching human hair fibres into the yield region at elevated temperatures. The role of correlation between unfolding units has been studied in more detail predicting an energy of ca. 12 kJ mol(-1) for the interface. The composite structure of hair at the nanometre scale was addressed using a particle-based model for a macrofibril. Mesoscale particles representing coiled coils of keratin proteins were assembled to filaments and embedded in a matrix of soft particles cross-linked to a network. The macrofibril was extended in a non-equilibrium computer simulation, while monitoring the tensile force. Thermal properties of the macrofibril in the yield region are in correspondence with the two-state model.     

The utilization of risk assessments in tactical command decisions

Traditional risk assessments (as delineated by regulatory agencies) use health outcome endpoints of interest to society as a whole, and are based on broad assumptions about the demographics of the potentially exposed populations and the routes of exposure. Immediacy of impact is not normally a major consideration. In tactical situations, the commander must balance considerations of short-term health effects against mission accomplishment. Often the commander will decide to accept a risk that would not be considered under other circumstances. The traditional tools of human-health and environmental risk assessment may be used, but the risk levels and projected consequences must be adapted to the tactical scenario (i.e. the performance decrement associated with a short-term exposure tactical operation vs. the long-term health out-come for an exposed population under 'normal conditions'). Risk assessors and health professionals must learn to articulate risk in terms that the tactical commander can place in his operational risk management (ORM) process. The process may require that the commander weigh non-health related mission critical considerations against health outcome issues. This presentation is intended to begin a dialogue that will lead to a harmonization of the use of risk assessment tools and their application in ORM as seen by tactical commanders, and a clarification of the strengths and limits of their utility in such applications.     

Field Monitoring of a Permeable Reactive Barrier for Removal of Chlorinated Organics

The application of zero-valent iron (Fe0) in the funnel-and-gate permeable reactive barrier (PRB) installed at the Vapokon site, Denmark, was conducted in 1999 to remediate the groundwater contaminated by chlorinated aliphatic hydrocarbons (CAHs). Over the past 4?years, except in September 2002 and January 2003, about 92.4–97.5% CAH removal could be achieved with the PRB. Although there was a continuous decrease in total alkalinity (90.3%), calcium (81.7%), and sulfate (69.2%) ions in the groundwater crossing the PRB, probably caused by mineral precipitation and resulting in 0.88% porosity loss per year, no noticeable deterioration of the barrier’s performance was observed between March 2000, and August 2003. Instead, climatic variation in the barrier’s performance on CAH dechlorination was examined. The dechlorination rates in the cold season (January 2003 and March 2000) were generally smaller than those in the hot season (August 2003, September 2000, and September 2001). Besides, 1,2-dichloroethane and dichloromethane, which were proven to be not treatable by Fe0, could also be removed with the PRB, thereby suggesting enhancement from Fe0 adsorption or microbial degradation.     

Optical properties of N,N′-bis(3-phenoxy-3-phenoxy-phenoxy)-1,4,5,8-naphthalene-tetracarboxylic diimide by spectroscopic ellipsometry

Optical properties of N,N′-bis(3-phenoxy-3-phenoxy-phenoxy)-1,4,5,8-naphthalene-tetracarboxylic diimide were investigated using variable angle spectroscopic ellipsometry in the visible light range. An oscillator model with one Tauc–Lorentzian and three Gaussian oscillators was constructed and found physically consistent with the experimental results. No measurable optical anisotropy is found in-plane or out of the film plane, indicating a random arrangement of molecules in spin cast thin films. Refractive index n and absorption index k are reported in the 1.5–4.5 eV (840 nm to 280 nm) optical range.     

Fügen und Verbinden mit UV‐ und lichthärtenden Acrylaten

Joining and connecting with the help of uv‐ and lighthardening acrylates. At the moment in the field of construction adhesively bonded joints are only carried out by the use of silicones. On the other hand alternative adhesives offer many advantages. Beside a higher strength also thinner adhesive bonded joints with completely transparent or coloured joints are possible. To apply adhesively bonded glass the design and calculation of these connections must be ensured. In a current joint research project transparent adhesives of higher strength, will be investigated for their suitability for structural glass. Typical glass constructions, which require transparent, elastic and non‐ageing adhesive bonded joints are subject for investigation.     

Hardness and carbonate effects on the reactivity of zero-valent iron for Cr(VI) removal

Zero-valent iron (Fe0) was used to remove hexavalent chromium, Cr(VI), in groundwater via a coupled reduction-oxidation reaction. Nine columns were set up under various groundwater geochemistry to investigate the effects of hardness and carbonate on Cr(VI) removal. The Cr(VI) removal capacity of Fe0 was found to be about 4 mgCr/g Fe0 in the control column (i.e., column 1). A slight decrease in the Cr(VI) removal capacity was found in the presence of calcium hardness. However, there was a 17% drop in the Cr(VI) removal capacity when magnesium hardness was present at low to moderately hard level. Results also revealed that carbonate changed the morphology of the Fe0 by formation of pale green precipitates on the iron filings. Furthermore, there was a 33% decrease in the Cr(VI) removal capacity of Fe0 when both carbonate and hardness ions were present. In general, the presence of hardness ions and carbonate in groundwater have great impact on the Fe0 by formation of passivated precipitates, such as CaCO3, on the Fe0 surface resulting in a diminished lifespan of the Fe0 by blocking electron transfer.