Variability of the rock properties and the uncertainty associated with their estimation in the blocks mined and processed becloud the decision making in the mining value chain. In addition to grades ...of elements and minerals of interest, the presence of deleterious materials, as well as varying geometallurgical properties of rock materials have significant impacts on the economic performance of mining projects. Researchers are faced with the challenge that there are limited opportunities for benchmarking mining methods and technologies as this type of information is proprietary from mining companies and seldom shared for research purposes.In this thesis, a methodology was developed for building a high-resolution realistic synthetic block model containing grades as well as mineralogical and geological properties for benchmarking purposes. A high-resolution block model, featuring 128 million nodes, was developed for a porphyry copper deposit and used to simulate mining decisions through the mine value chain. To achieve this, samples were extracted from the model by means of a drillhole campaign to allow for comparison of estimation and planning decisions with the actual model data, which provides access to the ground truth. Applications of the developed approach to benchmark advanced mine planning techniques including machine-learning tools in prediction, forecasting, and decision making were also discussed.
Thin polymer films and coatings are used to tailor the properties of surfaces in various applications such as protection against corrosion, biochemical functionalities or electronic resistors. ...Polymer brushes are a certain kind of thin polymer films, where polymer chains are covalently grafted to a substrate and straighten up to form a brush structure. Here we report on differences and similarities between polymer brushes and spin-coated polymer films from polystyrene and polymethyl methacrylate with special emphasis on surface roughness and roughness correlation. The phenomenon of roughness correlation or conformality describes the replication of the roughness profile from the substrate surface to the polymer surface. It is of high interest for polymer physics of brush layers as well as applications, in which a homogeneous polymer layer thickness is required. We demonstrate that spin-coated films as well as polymer brushes show roughness correlation, but in contrast to spin-coated films, the correlation in brushes is stable to solvent vapor annealing. Roughness correlation is therefore an intrinsic property of polymer brushes.
Although current desalination technologies are mature enough and advanced, the shortage of freshwater is still considered as one of the most pressing global issues. Therefore, there is a strong ...incentive to explore and investigate new potential methods with low energy consumption. We have previously reported that reversible thermally induced sorption/desorption process using polymeric hydrogels hold promise for water desalination with further development. In order to develop a more effective hydrogels architecture, polyelectrolyte moieties were introduced in this work as pendent chains and a thermally responsive polymer as network backbone using reversible addition-fragmentation chain transfer (RAFT) polymerisation. The ability of the comb-type polymeric hydrogels to desalinate water was evaluated. These hydrogels were proved to absorb water with low salinity from brine solution of 2 g L - 1 NaCl and release the absorbed water at relatively low temperature conditions of 50 ∘ C. The fraction of the grafted polyacrylic acid and the comb-chain length were varied to understand their influence on the swelling/deswelling behaviour for these hydrogels. The ionic fraction in the hydrogels and the resulting hydrophilic/hydrophobic balance are crucial for the proposed desalination process. In contrast, the comb-chain length impacted the swelling behaviour of hydrogels but showed relatively little influence on the dewatering process.
On the basis of the major application for block copolymers to use them as separation membranes, lithographic mask, and as templates, the preparation of highly oriented nanoporous thin films requires ...the selective removal of the minor phase from the pores. In the scope of this study, thin film of polystyrene-
-poly(ethylene oxide) block copolymer with a photocleavable junction groups based on ortho-nitrobenzylester (ONB) (PS-
-PEO) was papered via the spin coating technique followed by solvent annealing to obtain highly-ordered cylindrical domains. The polymer blocks are cleaved by means of a mild UV exposure and then the pore material is washed out of the polymer film by ultra-pure water resulting in arrays of nanoporous thin films to remove one block. The removal of the PEO materials from the pores was proven using the grazing-incidence small-angle X-ray scattering (GISAXS) technique. The treatment of the polymer film during the washing process was observed in real time after two different UV exposure time (1 and 4 h) in order to draw conclusions regarding the dynamics of the removal process. In-situ X-ray reflectivity measurements provide statistically significant information about the change in the layer thickness as well as the roughness and electron density of the polymer film during pore formation. 4 H UV exposure was found to be more efficient for PEO cleavage. By in-situ SFM measurements, the structure of the ultra-thin block copolymer films was also analysed and, thus, the kinetics of the washing process was elaborated. The results from both measurements confirmed that the washing procedure induces irreversible change in morphology to the surface of the thin film.
Highly ordered block copolymer thin films have been studied extensively during the last years because they afford versatile self-assembled morphologies via a bottom-up approach. They promise to be ...used in applications such as polymeric membranes or templates for nanostructured materials. Among the block copolymer structures, perpendicular cylinders have received strong attention due to their ability to fabricate highly ordered nanopores and nanowires. Nanopores can be created from a thin block copolymer film upon the removal of one block by selective etching or by dissolution of one polymer block. Here we demonstrate the utilization of polystyrene-block-poly(ethylene oxide) diblock copolymer (PS- hν-PEO) with an ortho-nitrobenzyl ester (ONB) as the photocleavable block-linker to create highly ordered thin films. Removal of the PEO block by choosing an appropriate solvent upon photocleavage is expected to yield arrays of nanopores decorated with functional groups, thus lending itself to adsorption or filtration uses. While the feasibility of this approach has been demonstrated, it is crucial to understand the influence of removal conditions (i.e., efficiency of photocleavage as well as best washing solvent) and to evaluate changes in the surface topology and inner structure upon photocleavage. To this end, the time dependence evolution of the surface morphology of block copolymer thin films was studied using grazing-incidence small-angle X-ray scattering (GISAXS) technique in combination with scanning probe microscopy.
In this work, a pioneering study on the electrical properties of composite carbon nanofibres (CNFs) using current-sensitive atomic force microscopy (CS-AFM) has been demonstrated. CNFs are highly ...interesting materials which are usable in a wide array of applications
electrode materials for biosensors, lithium ion batteries, fuel cells and supercapacitors. CNFs offer a high specific surface area and thus have a high contact area for charge transfer. CNFs can be produced using spinnable polyacrylonitrile (PAN) as a precursor for carbonisation. For the purpose of developing efficient CNFs with high conductivity and power density, silver nanoparticle (AgNPs)-containing PAN solutions were electrospun to form composite nanofibres which was followed by heat treatment. The applied voltage of the spinning setup and the content of both PAN and the silver nanoparticles in the spinning solution were varied in order to study their influence on the morphology and the electrical properties of the nanofibres. The resultant morphologies and fibre diameters were determined by scanning electron microscopy (SEM). The formation of silver nanoparticles was characterised in solution by UV-visible absorption spectroscopy and dynamic light scattering (DLS), while energy-dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) were carried out to investigate the presence as well as the average diameter of the AgNPs. The electrical properties of the CNFs were investigated using CS-AFM. This technique gives us the possibility to explore the electrical properties of single fibers and hence derive relationships between the structural features and the electrical properties. Our results show that the composite CNFs have a higher electrical conductivity than the neat CNFs and both the average diameter of the fibers and the electrical conductivity increase with an increasing AgNP content.
The contamination of soil with hydrocarbons due to accidents or leakages is a wide-spread phenomenon with potential health risks. So far, no technique has been available for fast on-site ...identification and quantitative determination of the contaminant. This information, however, would be necessary for the assessment of decontamination measures to be taken for the area under consideration either by excavation or a biotechnical approach. All methods in current practice require a time-consuming retrieval and transportation of contaminated soil samples to the laboratory for further qualitative and quantitative analysis. Based on diffuse reflection measurements with a hand-held NIR spectrometer, in the present communication, results on the qualitative discrimination and on the quantitative determination of hydrocarbon contaminants (gasoline, diesel and oil) with standard errors of cross validation between 0.3% to 0.5% (w/w) in different types of soil are reported. The presented approach can serve as proof of concept to replace conventional methods in the case of hazardous incidents with high contamination concentrations by on-site investigations for a fast assessment of decontamination measures and an effective monitoring of their success. Furthermore, the method is not limited only to the characterisation of areal pollution, but can also be easily extended to depth-profiling measurements.
Localization is a self-position estimation problem and is one of the most critical research areas in autonomous mobile robots. This study presents novel solutions to two significant practical ...challenges in localization. The initial challenge pertains to the lack of distinct features within the environment, while the second involves the imperfectness of the map. Many studies are based on Extended Kalman Filter (EKF) and they need specific features from the environment for localization. The edges and corners are the popular natural feature types to be used in grid maps. The proposed study promises accurate and fast position tracking in the grid maps which have very few corners and edges. To achieve high performance in such a challenging map, we propose the virtual dynamic point landmark (VDPL) approach in this paper. VDPL does not need specific features such as edges and corners, and any part of the map can be used as a landmark. Since the real-world applications are based on imperfect maps, mostly generated by SLAM (Simultaneous Localization and Mapping) algorithm, the probabilistic distribution of the measurement model and measurement predictions are incorrect. In this study, the position errors that occur as a result of this incorrectness are alleviated by modifying the EKF algorithm. The modified equations of EKF for taking into account the map errors are clearly shown in the paper. The efficiency of the proposed solution is demonstrated in multiple simulations which are performed in randomly generated maps. Moreover, the benefits and real-time performance of the proposed approach are provided by real-world tests using an autonomous wheelchair platform. We believe that the methods developed in this study will improve the localization performance of autonomous robots that operate in challenging environments in terms of feature structure.
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