A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS)

The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.     

Chloride binding of cement-based materials subjected to external chloride environment – A review

This paper reviews the chloride binding of cement-based materials subjected to external chloride environments. Chloride ion exist either in the pore solution, chemically bound to the hydration products, or physically held to the surface of the hydration products. Chloride binding of cement-based material is very complicated and influenced by many factors, such as chloride concentration, cement composition, hydroxyl concentration, cation of chloride salt, temperature, supplementary cementing materials, carbonation, sulfate ions and electrical field etc. Four different types of binding isotherms, namely linear, Langmuir, Freundlich and BET binding isotherm have been proposed to describe the relationship between free and bound chloride, none of which can accurately express the relationships between free and bound chloride within the whole concentration range. Freundlich binding isotherm seems to be the most approximate one. However, some field data fit linear isotherm well. This may be ascribed to the leakage of hydroxyl ion. Many service life prediction models based on diffusion mechanism alone have been proposed during the past two decades. If chloride ion binding is not considered in the models, it underestimates the predicated service life.     

Athermal arrayed waveguide gratings in silicon-on-insulator by overlaying a polymer cladding on narrowed arrayed waveguides

Athermal arrayed waveguide gratings (AWGs) in silicon-on-insulator (SOI) are experimentally demonstrated for the first time to our knowledge. By using narrowed arrayed waveguides, and then overlaying a polymer layer, the wavelength temperature dependence of the AWGs is successfully reduced to -1.5 pm/°C, which is more than 1 order of magnitude less than that of normal SOI AWGs. The athermal behavior of the AWGs is obtained with little degradation of their performance. For the central channel, the cross talk is less than -15 dB and the insertion loss is around 2.6 dB. Good characteristics can be maintained with temperatures up to 75 °C. The total size of the device is 350 μm × 250 μm.     

Road safety risk evaluation and target setting using data envelopment analysis and its extensions

Currently, comparison between countries in terms of their road safety performance is widely conducted in order to better understand one's own safety situation and to learn from those best-performing countries by indicating practical targets and formulating action programmes. In this respect, crash data such as the number of road fatalities and casualties are mostly investigated. However, the absolute numbers are not directly comparable between countries. Therefore, the concept of risk, which is defined as the ratio of road safety outcomes and some measure of exposure (e.g., the population size, the number of registered vehicles, or distance travelled), is often used in the context of benchmarking. Nevertheless, these risk indicators are not consistent in most cases. In other words, countries may have different evaluation results or ranking positions using different exposure information. In this study, data envelopment analysis (DEA) as a performance measurement technique is investigated to provide an overall perspective on a country's road safety situation, and further assess whether the road safety outcomes registered in a country correspond to the numbers that can be expected based on the level of exposure. In doing so, three model extensions are considered, which are the DEA based road safety model (DEA-RS), the cross-efficiency method, and the categorical DEA model. Using the measures of exposure to risk as the model's input and the number of road fatalities as output, an overall road safety efficiency score is computed for the 27 European Union (EU) countries based on the DEA-RS model, and the ranking of countries in accordance with their cross-efficiency scores is evaluated. Furthermore, after applying clustering analysis to group countries with inherent similarity in their practices, the categorical DEA-RS model is adopted to identify best-performing and underperforming countries in each cluster, as well as the reference sets or benchmarks for those underperforming ones. More importantly, the extent to which each reference set could be learned from is specified, and practical yet challenging targets are given for each underperforming country, which enables policymakers to recognize the gap with those best-performing countries and further develop their own road safety policy.     

Connect & Drive: design and evaluation of cooperative adaptive cruise control for congestion reduction

Road throughput can be increased by driving at small inter-vehicle time gaps. The amplification of velocity disturbances in upstream direction, however, poses limitations to the minimum feasible time gap. This effect is covered by the notion of string stability. String-stable behavior is thus considered an essential requirement for the design of automatic distance control systems, which are needed to allow for safe driving at time gaps well below 1 s. Using wireless inter-vehicle communications to provide real-time information of the preceding vehicle, in addition to the information obtained by common Adaptive Cruise Control (ACC) sensors, appears to significantly decrease the feasible time gap, which is shown by practical experiments with a test fleet consisting of six passenger vehicles. The large-scale deployment of this system, known as Cooperative ACC (CACC), however, poses challenges with respect to the reliability of the wireless communication system. A solution for this scalability problem can be found in decreasing the transmission power and/or beaconing rate, or adapting the communications protocol. Although the main CACC objective is to increase road throughput, the first commercial application of CACC is foreseen to be in truck platooning, since short distance following is expected to yield significant fuel savings in this case.

     

The use of interorganisational ICT in United States construction projects

In recent research, the use of ICT applications in real time construction projects have been documented and analysed extensively. However, there is a need for identifying and analysing in-depth the mechanisms influencing the use of interorganisational ICT applications and for solutions to eliminate potential barriers to the successful use of ICT. A model is developed providing insights in these mechanisms. Based on this model and expert interviews in the United States construction industry directions for solutions to barriers to the successful use of interorganisational ICT — document management applications, workflow management applications, and product modelling applications — in construction projects are formulated. These solutions focus on stimulating the personal motivation to use ICT, the external motivation to use this technology, and facilitating conditions in terms of knowledge and skills and acting opportunities to use ICT.     

Using an eye tracker for accurate eye movement artifact correction

We present a new method to correct eye movement artifacts in electroencephalogram (EEG) data. By using an eye tracker, whose data cannot be corrupted by any electrophysiological signals, an accurate method for correction is developed. The eye-tracker data is used in a Kalman filter to estimate which part of the EEG is of ocular origin. The main assumptions for optimal correction are summed and their validity is proven. The eye-tracker-based correction method is objectively evaluated on simulated data of four different types of eye movements and visually evaluated on experimental data. Results are compared to three established correction methods: Regression, Principal Component Analysis, and Second-Order Blind Identification. A comparison of signal to noise ratio after correction by these methods is given in Table II and shows that our method is consistently superior to the other three methods, often by a large margin. The use of a reference signal without electrophysiological influences, as provided by an eye tracker, is essential to achieve optimal eye movement artifact removal.