Abstract: Imaging of crystalline phase distributions in heterogeneous materials, either plane projected or in virtual cross sections of the object under investigation, can be achieved by scanning X-ray powder diffraction employing X-ray micro beams and X-ray-sensitive area detectors. Software exists to convert the two-dimensional powder diffraction patterns that are recorded by these detectors to one-dimensional diffractograms, which may be analysed by the broad variety of powder diffraction software developed by the crystallography community. However, employing these tools for the construction of crystalline phase distribution maps proves to be very difficult, especially when employing micro-focused X-ray beams, as most diffraction software tools have mainly been developed having structure solution in mind and are not suitable for phase imaging purposes. XRDUA has been developed to facilitate the execution of the complete sequence of data reduction and interpretation steps required to convert large sequences of powder diffraction patterns into a limited set of crystalline phase maps in an integrated fashion.

Abstract: In order to narrow the band gap of TiO2, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO2 and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO2 and PEALD TiN, the as synthesized TiOxNy films showed different band gaps (from 1.91 eV to 3.14 eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO2 films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO2 along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity.

Abstract: Soot deposition has the negative ability to devalue the aesthetic appearance of buildings. Titanium dioxide applied on the building material is one way to counteract this problem as it provides air-purifying and self-cleaning properties due to its photocatalytic activity. In literature, photocatalytic soot oxidation was described, but until now, little information was available about the influence of process parameters on the photocatalytic degradation efficiency. The influence of three process parameters was tested in this study, namely TiO2 concentration, soot concentration and water-to-cement ratio (WIC-ratio) of the mortar substrates. The results revealed 50 mu gTiO(2) cm(-2) is better to use on the cementitious materials than 250 mu gTiO(2) cm(-2). The soot concentrations occurring in real-world situations will not inhibit the photocatalyst to be activated by light. Furthermore, the photonic efficiency increases slightly for lower WIC-ratios. This can be of interest for structural building applications, since a lower WIC-ratio results in a lower porosity of the samples and consequently in an increase in mortar strength. (C) 2013 Elsevier B.V. All rights reserved.

Abstract: Immobilization of photocatalytic powder is crucial to obtain industrially relevant purification processes. To achieve this goal, self-supporting TiO2 foams were manufactured by a polyacrylamide gel process. These gels were calcined at different temperatures to study the effect of the calcination temperature on foam characteristics (rigidity, crystallinity, and porosity) and its influence on photocatalytic activity. The results show that an optimal degradation is achieved for those foams calcined between 700 and 800°C. Calcination at higher temperatures results in a steep decrease in activity, explained by stability issues of the material due to formation of Na2SO4 phases and a larger rutile fraction.

Abstract: Many studies on technology adoption demonstrate that uncertainty leads to a postponement of investments by integrating a wait option in the economic analysis. The aim of this study however is to demonstrate how the investment in new technologies can be stimulated by integrating an option to abandon. Furthermore, this real option analysis not only considers the ex ante decision analysis of the investment in a new technology under uncertainty, but also allows for an ex post evaluation of the investment. Based on a case study regarding the adoption of an innovative groundwater remediation strategy, it is demonstrated that when the option to abandon the innovative technology is taken into account, the decision maker decides to invest in this technology, while at the same time it determines an optimal timing to abandon the technology if its operation proves to be inefficient. To reduce uncertainty about the effectiveness of groundwater remediation technologies, samples are taken. Our analysis shows that when the initial belief in an effective innovative technology is low, it is important that these samples provide correct information in order to justify the adoption of the innovative technology. (C) 2014 Elsevier B.V. All rights reserved.

Abstract: The amount of animal manure that can be brought back to agricultural land is limited by legislation. Because pig manure is available in too large quantities in some areas, we investigate the techno-economic feasibility of converting it into valuable products. First, slurry is separated in water, a thick fraction and a fertilizer concentrate poor in phosphate. Then, the thick fraction is dried and pyrolyzed. Our goal is to identify the optimal pyrolysis and activation conditions for the production of biochar or activated carbon. The latter has interesting adsorption characteristics due to the presence of nitrogen. It can also be used as a soil amendment as it improves biomass quantity and quality. On top, it immobilizes toxic elements and stores carbon in the soil. Char thus has many interesting characteristics and can be valued in different ways. The economic feasibility has been explored by a first techno-economic modelling iteration. The critical factors influencing the feasibility are identified by Monte Carlo simulations for further improvement of the process design.

Abstract: Given the historical development of land tenure in South Africa, the aim of this article is to examine the best routes to alleviate poverty and retain sustainable agriculture in the country. First, a theoretical framework is presented that relates land tenure to sustainability, and three historical periods (pre-colonial, colonial, and apartheid) are then considered to explain the changes in land tenure and their consequences. The progress and main limitations of post-apartheid land reform to approach agricultural sustainability and alleviate poverty are discussed. Based on the analysis, different possibilities for future land reform are elaborated, followed by some recommendations for future land-reform policies in South Africa.

Abstract: In this paper, the technical and economic advantages of combining conversion technologies into a multi-dimensional plant primarily using regional biomass residues are investigated. The main objective is to show how locally available biomass can be used more efficiently as a source for renewable energy and bio-based products. Therefore, not only is the theoretical perspective considered, but also a reality check for the local situation is taken into account. Although industrial attitude toward biorefineries is positive, the efficient production of a portfolio of bio-based products has not yet been implemented. A biorefinery concept for Moerdijk (the Netherlands) was developed, focusing on grass refining, production of pyrolysis oil, biodiesel production, and bio-LNG production. Grass refining is the most experimental technique of all proposed conversion techniques. In terms of development, pyrolysis oil and bio-LNG production are in the demonstration phase. Anaerobic digestion and biodiesel production are proven techniques. It is shown that this concept allows for synergies with regard to the utilization of residue flows from internal processes. Furthermore, it is demonstrated that by integrating different conversion technologies, an economically feasible concept can be developed in which technologies, currently residing in a demonstration phase, can also be brought to the market. (c) 2013 Society of Chemical Industry and John Wiley & Sons, Ltd

Abstract: In the commercialisation of photocatalytic air purifiers, the performance as well as the cost of the catalytic material plays an important role. Where most comparative studies only regard the photocatalytic activity as a decisive parameter, in this study both activity and cost are taken into account. Using a cost-effectiveness analysis, six different commercially available TiO2-based catalysts are evaluated in terms of their activities in photocatalytic degradation of acetaldehyde as a model reaction for indoor air purification.

Abstract: Innovative bioenergy projects show a growing diversity in biomass pathways, transformation technologies and end-products, leading to complex new processes. Existing energy-based indicators are not designed to include multiple impacts and are too constrained to assess the sustainability of these processes. Alternatively, indicators based on exergy, a measure of “qualitative energy”, could allow a more holistic view. Exergy is increasingly applied in analyses of both technical and biological processes. But sustainability assessments including exergy calculations, are not very common and are not generally applicable to all types of impact. Hence it is important to frame the use of exergy for inclusion in a sustainability assessment. This paper reviews the potentials and the limitations of exergy calculations, and presents solutions for coherent aggregation with other metrics. The resulting approach is illustrated in a case study. Within the context of sustainability assessment of bioenergy, exergy is a suitable metric for the impacts that require an ecocentric interpretation, and it allows aggregation on a physical basis. The use of exergy is limited to a measurement of material and energy exchanges with the sun, biosphere and lithosphere. Exchanges involving services or human choices are to be measured in different metrics. This combination provides a more inclusive and objective sustainability assessment, especially compared to standard energy- or carbon-based indicators. Future applications of this approach in different situations are required to clarify the potential of exergy-based indicators in a sustainability context. (C) 2013 Elsevier Inc. All rights reserved.

Abstract: The selection and identification of a suitable hydrological model structure is a more challenging task than fitting parameters of a fixed model structure to reproduce a measured hydrograph. The suitable model structure is highly dependent on various criteria, i.e. the modeling objective, the characteristics and the scale of the system under investigation and the available data. Flexible environments for model building are available, but need to be assisted by proper diagnostic tools for model structure selection. This paper introduces a qualitative method for model component sensitivity analysis. Traditionally, model sensitivity is evaluated for model parameters. In this paper, the concept is translated into an evaluation of model structure sensitivity. Similarly to the one-factor-at-a-time (OAT) methods for parameter sensitivity, this method varies the model structure components one at a time and evaluates the change in sensitivity towards the output variables. As such, the effect of model component variations can be evaluated towards different objective functions or output variables. The methodology is presented for a simple lumped hydrological model environment, introducing different possible model building variations. By comparing the effect of changes in model structure for different model objectives, model selection can be better evaluated. Based on the presented component sensitivity analysis of a case study, some suggestions with regard to model selection are formulated for the system under study: (1) a non-linear storage component is recommended, since it ensures more sensitive (identifiable) parameters for this component and less parameter interaction; (2) interflow is mainly important for the low flow criteria; (3) excess infiltration process is most influencing when focussing on the lower flows; (4) a more simple routing component is advisable; and (5) baseflow parameters have in general low sensitivity values, except for the low flow criteria. (C) 2014 Elsevier B.V. All rights reserved.