Pilot experiments with electrodialysis and ozonation for the production of a fertiliser from urine.

Pilot tests were performed with a process combination of electrodialysis and ozonation for the removal of micropollutants and the concentration of nutrients in urine. In continuous and batch experiments, maximum concentration factors up to 3.5 and 4.1 were obtained, respectively. The desalination capacity did not decrease significantly during continuous operation periods of several weeks. Membrane cleaning after 195 days resulted in approximately 35% increase in desalination rate. The Yeast Estrogen Screen (YES), a bioassay that selectively detects oestrogenic compounds, confirmed that about 90% of the oestrogenic activity was removed by electrodialysis. HPLC analysis showed that ibuprofen was removed to a high extent, while other micropollutants were below the detection limit. In view of the fact that ibuprofen is among the most rapidly transported micropollutants in electrodialysis processes, this result indicates that electrodialysis provides an effective barrier for micropollutants. Standardised plant growth tests were performed in the field with the salt solution resulting from the treatment by electrodialysis and subsequent ozonation. The results show that the plant height is comparable to synthetic fertilisers, but the crop yield is slightly lower. The latter is probably caused by volatilisation losses during field application, which can be prevented by improved application technologies.     

Local calibration of rigid pavement performance models using resampling methods

The performance prediction models in the Pavement-ME design software are nationally calibrated using in-service pavement material properties, pavement structure, climate and truck loadings, and performance data obtained from the Long-Term Pavement Performance programme. The nationally calibrated models may not perform well if the inputs and performance data used to calibrate those do not represent the local design and construction practices. Therefore, before implementing the new M-E design procedure, each state highway agency (SHA) should evaluate how well the nationally calibrated performance models predict the measured field performance. The local calibrations of the Pavement-ME performance models are recommended to improve the performance prediction capabilities to reflect the unique conditions and design practices. During the local calibration process, the traditional calibration techniques (split sampling) may not necessarily provide adequate results when limited number of pavement sections are available. Consequently, there is a need to employ statistical and resampling methodologies that are more efficient and robust for model calibrations given the data related challenges encountered by SHAs. The main objectives of the paper are to demonstrate the local calibration of rigid pavement performance models and compare the calibration results based on different resampling techniques. The bootstrap is a non-parametric and robust resampling technique for estimating standard errors and confidence intervals of a statistic. The main advantage of bootstrapping is that model parameters estimation is possible without making distribution assumptions. This paper presents the use of bootstrapping and jackknifing to locally calibrate the transverse cracking and IRI performance models for newly constructed and rehabilitated rigid pavements. The results of the calibration show that the standard error of estimate and bias are lower compared to the traditional sampling methods. In addition, the validation statistics are similar to that of the locally calibrated model, especially for the IRI model, which indicates robustness of the local model coefficients.     

Succinctness of pattern-based schema languages for XML

Martens et al. defined a pattern-based specification language equivalent in expressive power to the widely adopted XML Schema definitions (XSDs). This language consists of rules of the form $(r,s)$ where r and s are regular expressions and can be seen as a type-free extension of DTDs with vertical regular expressions. Sets of such rules can be interpreted both in an existential or universal way. In the present paper, we study the succinctness of both semantics w.r.t. each other and w.r.t. the common abstraction of XSDs in terms of single-type extended DTDs. The investigation is carried out relative to three kinds of vertical pattern languages: regular, linear, and strongly linear patterns. We also consider the complexity of the simplification problem for each of the considered pattern-based schemas.     

Multi-cue hand detection and tracking for a head-mounted augmented reality system

With the recent developments in wearable augmented reality (AR), the role of natural human–computer interaction is becoming more important. Utilization of auxiliary hardware for interaction introduces extra complexity, weight and cost to wearable AR systems and natural means of interaction such as gestures are therefore more desirable. In this paper, we present a novel multi-cue hand detection and tracking method for head-mounted AR systems which combines depth, color, intensity and curvilinearity. The combination of different cues increases the detection rate, eliminates the background regions and therefore increases the tracking performance under challenging conditions. Detected hand positions and the trajectories are used to perform actions such as click, select, etc. Moreover, the 6 DOF poses of the hands are calculated by approximating the segmented regions with planes in order to render a planar menu (interface) around the hand and use the hand as a planar selection tool. The proposed system is tested on different scenarios (including markers for reference) and the results show that our system can detect and track the hands successfully in challenging conditions such as cluttered and dynamic environments and illumination variance. The proposed hand tracker outperforms other well-known hand trackers under these conditions.     

Ultra-Low-Power Interface Chip for Autonomous Capacitive Sensor Systems

Traditionally, most of the sensor interfaces must be tailored towards a specific application. This approach results in a high recurrent design cost and time to market. On the other hand, generic sensor interface design reduces the costs and offers a handy solution for multisensor applications. This paper presents a generic sensor interface chip (GSIC), which can read out a broad range of capacitive sensors. It contains capacitance-to-voltage converters, a switched-capacitor amplifier, an analog-to-digital converter, oscillators, clock generation circuits and a reference circuit. The system combines a very low-power design with a smart energy management, which adapts the current consumption according to the accuracy and speed requirements of the application. The GSIC is used in a pressure and an acceleration monitoring system. The pressure monitoring system achieves a current drain of 2.3 muA for a 10-Hz sample frequency and an 8-bit accuracy. In the acceleration monitoring system, we measured a current of 3.3 muA for a sample frequency of 10 Hz and an accuracy of 9 bits     

Hybrid cascode feedforward compensation for nano-scale low-power ultra-area-efficient three-stage amplifiers

A modified frequency compensation technique is proposed for low-power area-efficient three-stage amplifiers driving medium to large capacitive loads. Coined hybrid cascode feedforward compensation (HCFC), the total compensation capacitor is divided and shared between two internal high-speed feedback loops instead of only one loop as is common in prior art. Detailed analysis of this technique shows significant improvement in terms of bandwidth and stability. This is verified for a 1.2-V amplifier driving a 500-pF capacitive load in 90-nm CMOS technology, where HCFC reduces the total capacitor size and improves the gain-bandwidth by at least 30% and 40% respectively, compared to the prevailing schemes.     

Ester-functionalized poly(3-alkylthiophene) copolymers: Synthesis,physicochemical characterization and performance in bulk heterojunction organic solar cells

The introduction of functional moieties in the donor polymer (side chains) offers a potential pathway toward selective modification of the nanomorphology of conjugated polymer:fullerene active layer blends applied in bulk heterojunction organic photovoltaics, pursuing morphology control and solar cell stability. For this purpose, two types of poly(3-alkylthiophene) random copolymers, incorporating different amounts (10/30/50%) of ester-functionalized side chains, were efficiently synthesized using the Rieke method. The solar cell performance of the functionalized copolymers was evaluated and compared to the pristine P3HT:PCBM system. It was observed that the physicochemical and opto-electronic characteristics of the polythiophene donor material can be modified to a certain extent via copolymerization without (too much) jeopardizing the OPV efficiency, as far as the functionalized side chains are introduced in a moderate ratio (<30%) and that preference is given to side chains with a small molar volume. A range of complementary techniques – UV–Vis spectroscopy, (modulated temperature) differential scanning calorimetry, transmission electron microscopy and X-ray diffraction analysis – indicated that variations in polymer crystallinity, while maintaining a high level of regioregularity, are probably the main factor responsible for the observed differences.     

Use of the yeast Hansenula polymorpha (Pichia angusta) to remove contaminating sugars from ethyl beta-D-fructofuranoside produced during sucrose ethanolysis catalysed by invertase

Alkyl glycosides are interesting intermediates for the production of biodegradable surfactants. Synthesis of ethyl beta-d-fructofuranoside by invertase-catalysed ethanolysis of sucrose has been extensively reported in literature. However, this procedure yields mixtures of glucose, fructose, sucrose and ethyl beta-d-fructofuranoside. Purification of ethyl beta-d-fructofuranoside from such mixtures by chromatographic methods is laborious, difficult to scale up and requires organic solvents. The yeast Hansenula polymorpha grows rapidly on glucose, fructose and sucrose. Sucrose hydrolysis in this yeast is catalysed by an intracellular alpha-glucosidase ('maltase'); consequently, H. polymorpha should be unable to hydrolyse ethyl beta-d-fructofuranoside. Indeed, aerobic cultivation of H. polymorpha on sugar mixtures obtained by invertase-catalysed ethanolysis of sucrose resulted in the complete removal of contaminating sugars, leaving ethyl beta-d-fructofuranoside as the sole organic compound in culture supernatants. Pure ethyl beta-d-fructofuranoside was recovered from the supernatants by mixed-bed ion exchange chromatography with an 86% yield.     

Low-voltage low-power fully-integratable automatic gain controls

This paper discusses the design of low-voltage low-power fully-integratable automatic gain controls. Four different AGCs are presented, all consisting of three elementary building blocks: a controlled amplifier, a comparator and a voltage follower. Their design is treated separately. As an example, the final section describes an automatic gain control for hearing instruments, realized in a bipolar process.