Abstract: Organic carbon introduction in the soil to initiate remedial measures, nitrate infiltration due to agricultural practices or sulphate intrusion owing to industrial usage can influence the redox conditions and pH, thus affecting the mobility of heavy metals in soil and groundwater. This study reports the fate of Zn and Cd in sandy aquifers under a variety of plausible in-situ redox conditions that were induced by introduction of carbon and various electron acceptors in column experiments. Up to 100% Zn and Cd removal (from the liquid phase) was observed in all the four columns, however the mechanisms were different. Metal removal in column K1 (containing sulphate), was attributed to biological sulphate reduction and subsequent metal precipitation (as sulphides). In the presence of both nitrate and sulphate (K2), the former dominated the process, precipitating the heavy metals as hydroxides and/or carbonates. In the presence of sulphate, nitrate and supplemental iron (Fe(OH)(3)) (K3), metal removal was also due to precipitation as hydroxides and/or carbonates. In abiotic column, K4, (with supplemental iron (Fe(OH)(3)), but no nitrate), cation exchange with soil led to metal removal. The results obtained were modeled using the reactive transport model PHREEQC-2 to elucidate governing processes and to evaluate scenarios of organic carbon, sulphate and nitrate inputs. (C) 2010 Elsevier B.V. All rights reserved.

Abstract: Organic and biological compounds (especially those related to the pharmaceutical industry) have always been of great interest for researchers due to their importance for the development of new drugs to diagnose, cure, treat or prevent disease. As many new API (active pharmaceutical ingredients) and their polymorphs are in nanocrystalline or in amorphous form blended with amorphous polymeric matrix (known as amorphous solid dispersion—ASD), their structural identification and characterization at nm scale with conventional X-Ray/Raman/IR techniques becomes difficult. During any API synthesis/production or in the formulated drug product, impurities must be identified and characterized. Electron energy loss spectroscopy (EELS) at high energy resolution by transmission electron microscope (TEM) is expected to be a promising technique to screen and identify the different (organic) compounds used in a typical pharmaceutical or biological system and to detect any impurities present, if any, during the synthesis or formulation process. In this work, we propose the use of monochromated TEM-EELS, to analyze selected peptides and organic compounds and their polymorphs. In order to validate EELS for fingerprinting (in low loss/optical region) and by further correlation with advanced DFT, simulations were utilized.

Abstract: Optical-photothermal infrared (O-PTIR) spectroscopy is a recently developed technique that provides spectra comparable to traditional transmission FTIR spectroscopy with nanometric spatial resolution. Hence, O-PTIR is a promising candidate for the analysis of historical paintings, as well as other cultural heritage objects, but its potential has not yet been evaluated.

Abstract: Optical photothermal infrared (O-PTIR) is a recently developed molecular spectroscopy technique that allows to noninvasively obtain chemical information on organic and inorganic samples at a submicrometric scale. The high spatial resolution (approximate to 450 nm), lack of sample preparation, and comparability of the spectral results to traditional Fourier transform infrared spectroscopy make it a promising candidate for the analysis of cultural heritage. In this work, the potential of O-PTIR for the noninvasive characterization of small heritage objects (few cubic centimeters) is demonstrated on a series of degraded 16th century brass and glass decorative elements. These small and challenging samples, typically encountering limitations with existing noninvasive methods such as macroscopic x-ray powder diffraction and mu Raman, were successfully characterized by O-PTIR, ultimately identifying the markers of glass-induced metal corrosion processes. The results clearly demonstrate how O-PTIR can be easily implemented in a noninvasive multianalytical strategy for the study of heritage materials, making it a fundamental tool for cultural heritage analyses.

Abstract: Optical hyperspectral cameras capture the spectral reflectance of materials. Since many materials behave as heterogeneous intimate mixtures with which each photon interacts differently, the relationship between spectral reflectance and material composition is very complex. Quantitative validation of spectral unmixing algorithms requires high-quality ground truth fractional abundance data, which are very difficult to obtain. In this work, we generated a comprehensive laboratory ground truth dataset of intimately mixed mineral powders. For this, five clay powders (Kaolin, Roof clay, Red clay, mixed clay, and Calcium hydroxide) were mixed homogeneously to prepare 325 samples of 60 binary, 150 ternary, 100 quaternary, and 15 quinary mixtures. Thirteen different hyperspectral sensors have been used to acquire the reflectance spectra of these mixtures in the visible, near, short, mid, and long-wavelength infrared regions (350-15385) nm. Overlaps in wavelength regions due to the operational ranges of each sensor and variations in acquisition conditions resulted in a large amount of spectral variability. Ground truth composition is given by construction, but to verify that the generated samples are sufficiently homogeneous, XRD and XRF elemental analysis is performed. We believe these data will be beneficial for validating advanced methods for nonlinear unmixing and material composition estimation, including studying spectral variability and training supervised unmixing approaches. The datasets can be downloaded from the following link: https://github.com/VisionlabHyperspectral/Multisensor_datasets.

Abstract: Optical and electronic properties of black phosphorus strongly depend on the number of layers and type of stacking. Using first-principles calculations within the framework of density functional theory, we investigate the electronic properties of bilayer black phosphorus with an interlayer twist angle of 90 degrees. These calculations are complemented with a simple (k) over right arrow . (p) over right arrow model which is able to capture most of the low energy features and is valid for arbitrary twist angles. The electronic spectrum of 90 degrees twisted bilayer black phosphorus is found to be x-y isotropic in contrast to the monolayer. However x-y anisotropy, and a partial return to monolayer-like behavior, particularly in the valence band, can be induced by an external out-of-plane electric field. Moreover, the preferred hole effective mass can be rotated by 90 degrees simply by changing the direction of the applied electric field. In particular, a +0.4 (-0.4) V angstrom(1) out-of-plane electric field results in a similar to 60% increase in the hole effective mass along the y (x) axis and enhances the m(y)*/m(x)* (m(x)*/m(y)*) ratio as much as by a factor of 40. Our DFT and (k) over right arrow . (p) over right arrow simulations clearly indicate that the twist angle in combination with an appropriate gate voltage is a novel way to tune the electronic and optical properties of bilayer phosphorus and it gives us a new degree of freedom to engineer the properties of black phosphorus based devices.

Abstract: Open waste dumps in Sri Lanka generate adverse environmental and socio-economic impacts due to inadequate maintenance. In this study, a concept of 'open waste dump mining' is suggested in order to minimise the environmental and socio-economic impacts, together with resource recovery. A model based on life cycle assessment and life cycle costing has been used to assess the environmental and economic feasibility of the suggested open waste dump mining concept. Two scenarios have been defined for a hypothetical case, dependent on the destination of the refuse derived fuel fraction. Scenario 1 comprises direct selling of refuse derived fuel as an alternative fuel to replace coal usage in the cement industry, while Scenario 2 consists of thermal treatment of refuse derived fuel with the objective of producing electricity. The study shows that both scenarios are beneficial from an environmental point of view, but not from an economic view point. However, economic profits can be obtained by adjusting waste transport distances and the price of electricity. The environmental analysis further reveals that the higher global warming potential of open waste dumps can be eliminated to a large extent by applying suggested mining and waste valorisation scenarios. (C) 2015 Elsevier B.V. All rights reserved.

Abstract: One primary goal of self-assembly in nanoscale regime is to implement multifunctional binary nanoparticle superlattices into practical use. In the last decade, considerable effort has been put into the fabrication of binary nanoparticle superlattices with controllable structure and stoichiometry. However, limited effort has been made in order to improve the stability of these binary nanoparticle superlattices, which is a prerequisite for their potential application. In this work, we demonstrate that the carbon deposition from specimen contamination can play an auxiliary role during the heat treatment of binary nanoparticle superlattices. With the in-situ carbon matrix formation, the thermal stability of CoAu 13 binary nanoparticle superlattices is unambiguously enhanced.

Abstract: One of the most striking but unexplained phenomena in the natural degradation of glass is the transformation of an almost colorless, transparent and homogeneous glass into a colored, opaque and heterogeneous degradation layer. In many cases, the degradation layer consists of numerous lamellae with a thickness between 0.1 and 10 pm. However, both internal structure and formation proess of laminated degradation layers remain unclear. In this paper, a model is proposed where we assume that transformed (degraded) glass consists of a random packing of nano-sized silica particles while the lamellae are the result of different packing densities. The model is able to connect the texture of numerous lamellae observed by several types of microscopic techniques with the structure at molecular level determined by means of chemical analysis. In addition, the model is able to explain numerous properties such as the parameters responsible for the contrast between lamellae. This contrast can be caused by differences in color, density, elemental composition, or surface roughness. (C) 2016 Elsevier B.V. All rights reserved.

Abstract: One of the most relevant problems in ship construction and maintenance nowadays concerns the corrosion in the double hull space ballast tanks of modern merchant vessels. On the one hand, there is a general consensus that the economic life span of such a vessel depends primarily upon the corrosion state of its ballast tanks, while on the other hand, the position of these tanks, squeezed between the outer hull and the loading tanks, makes routine inspection and maintenance almost impossible. Today, ship's ballast tanks are usually constructed in grade A steel and protected with a standard epoxy coating, backed up with sacrificial zinc anodes. Such a construction has been applied without significant alterations for many years. However, the objective of this economic study is to compare this construction method with some feasible alternatives. The considered alternatives are: (1) an increase of the scantlings, eliminating the necessity to replace corroded steel but diminishing the cargo carrying capacity of the ship, (2) application of the novel and more durable TSCF25 coating (3), the use of corrosion resistant steel in ship construction or (4) a standard PSPC15 coating combined with lifetime lasting aluminum sacrificial anodes. After running each alternative through a cost model including an extensive sensitivity analysis, it is concluded that the durable coating and the use of lifetime lasting aluminum anodes are bound to improve the actual basic tank concept. Corrosion resistant steel becomes attractive depending upon the evolution of the international steel market.

Abstract: One of the most basic criteria in documenting rangeland use prospects is the recognition of byproducts and their economic appraisal. The current study was conducted to assess the economic indices of exploiting byproduct production in Shahindej, Northwest Iran. For this purpose, 24 by-product-generating species were selected in 114 locations that belong to 49 rangeland units. The total expected value of 24 by-product generating species yield and forage production was calculated at 44.22 USD ha(-1). The results of this study showed that the sustainability of natural resources depends on the effective participation and empowerment of local communities. Furthermore, by-product exploitation contributes significantly to the local economy and employment while also reducing grazing intensity. Overall, the findings of this study show that by-product earnings should be considered in range management schemes and comprehensive natural-area management.

Abstract: One of the main objectives of implementing a circular economy system is the reuse and recycling of resources. Closing material cycles and renewable-based electricity and fuel production are essential to such systems. To achieve a high degree of circularity, waste streams have to be rethought and integrated from a cradle-to-grave to a cradle-to-cradle approach. However, today’s circular economy strategies mostly focus on current waste streams, while past waste streams, buried in landfills, could play an important role when recovering resources and energy. Hence, a well-thought-out circular economy strategy should include the re-integration of past waste streams. A grave-to-cradle approach is needed. Landfill mining (LFM), i.e. the excavation and processing of formerly buried waste to energy and materials, aims at utilizing these past waste streams. Doing so could bear potential economic, environmental, and societal burdens and benefits. Originating from landfill remediation projects, landfill mining has been further developed towards resource recovery. Today, using up-to-date technologies and following the most stringent environmental and social criteria, the concept is also known as enhanced landfill mining (ELFM). Throughout the relevant scientific literature, most attention is given to advances in technological development for (E)LFM, as well as its techno-economic and environmental assessment. Societal assessments of LFM projects are rare and treat societal impacts only selectively or from unilateral societal perspectives. If stakeholders are included in societal (E)LFM assessments, only industrial actors, like landfill operators, and governmental actors are asked to participate. A holistic stakeholder assessment for (E)LFM is missing. Moreover, the diverse societal impacts – ranging from socio-environmental benefits through the mitigation of health risks, over socio-economic benefits through land reclamation, and social benefits through community engagement, for example – are either only studied selectively or evaluated as one, entangling various societal effects. A holistic and specific assessment of societal factors affecting (E)LFM implementation is also missing. This thesis uses an anticipatory approach to tackle these challenges. This approach aims to integrate stakeholder values and include uncertainty through the use of multiple social perspectives and prospective modeling tools. In-depth interviews were conducted to develop a typology of (E)LFM stakeholders and to elicit the most important stakeholder needs. Stakeholders were selected along an extended quadruple helix framework, including industrial, institutional, scientific, and community actors. Furthermore, using system dynamics tools, namely causal loop diagrams, societal systems of (E)LFM could be visualized and analyzed. Finally, a discrete choice experiment was conducted to evaluate a set of societal factors representing the conversion of a landfill into a public park for recreational use. The in-depth interviews included landfill operators, technology providers and incubators, local governments and governmental institutions, as well as researchers and community members. To structure the diverse perspectives of stakeholders on (E)LFM, five stakeholder archetypes were developed: The Entrepreneur, the Engaged Citizen, the Visionary, the Technology Enthusiast, and the Skeptic. The archetypes capture important characteristics and opinions approaching (E)LFM implementation. They differ in risk perceptions, knowledge base, influence on (E)LFM’s systemic and project implementation, and their main concerns and motivations. Furthermore, 18 stakeholder needs were derived from the interviews. This includes societal, environmental, regulatory, and techno-economic needs. The needs are put in relation to the affected stakeholders and sustainability dimensions. Uncertainties that could potentially be reduced through the fulfillment of each need are qualitatively assessed. Quantitatively, stakeholders were focusing on societal, regulatory, and techno-economic needs, whereas qualitative emphasis was given to environmental needs, especially the avoidance of impacts from primary resource production. When meeting stakeholder needs fairly, intra- and inter-dimensional trade-offs have to be considered as different perspectives can lead to different and sometimes contradicting implications for (E)LFM implementation. To conceptualize societal systems of (E)LFM, causal loop diagrams were developed following system dynamics methodology. The visualizations show how (E)LFM is embedded in its societal context. Variables comprising the societal impact were analyzed, and mechanisms affecting the public project acceptance and the market acceptance of (E)LFM products worked out. Leverage points were identified, helping (E)LFM practitioners and policymakers to minimize potential risks and maximize potential benefits. To these count technological choices, stakeholder involvement, the after-use, quality standards, and LFM regulation in general, amongst others. To disentangle and evaluate societal impacts of (E)LFM, a discrete choice experiment was conducted deriving the utility of five distinct attributes: the size of a landfill, the project duration, job creation, disamenities, and climate impacts. To determine the willingness to pay, perform scenario analysis, and model policy simulations, a sixth attribute was added representing a cost factor for project implementation. Environmental considerations are most important to the sample, while project duration and disamenities also play a significant role. The scenario analysis and policy simulations show that taxing households for (E)LFM implementation is a viable option, especially for environmentally beneficial projects. Nonetheless, a favorable combination of the remaining attributes can compensate utility losses for environmentally questionable projects. As risks of classical landfill management practices are likely to grow with an updated evaluation of after-care periods lasting up to 100 years and more, positive effects of (E)LFM become even more noteworthy. Nonetheless, (E)LFM projects also pose potential risks like groundwater contamination or the reintroduction of hazardous materials. If executed poorly, (E)LFM projects could potentially do more harm than good. A mix of policy measures is recommended to push a major part of potential (E)LFM projects from being environmentally beneficial and economically inefficient to being societally, environmentally, and economically favorable. Overall, more research is necessary to integrate (E)LFM into circular economy strategies and build a sensible grave-to-cradle approach.

Abstract: One of the emerging challenges in the field of 3D characterization of nanoparticles by electron tomography is to avoid degradation and deformation of the samples during the acquisition of a tilt series. In order to reduce the required electron dose, various undersampling approaches have been proposed. These methods include lowering the number of 2D projection images, reducing the probe current during the acquisition, and scanning a smaller number of pixels in the 2D images. A comparison is made between these approaches based on tilt series acquired for a gold nanoparticle.

Abstract: On the basis of the time-dependent Ginzburg-Landau equation we studied the dynamics of the superconducting condensate in a wide two-dimensional sample in the presence of a perpendicular magnetic field and applied current. We could identify two critical currents: the current at which the pure superconducting state becomes unstable (J(c2)(1)) and the current at which the system transits from the resistive state to the superconducting state (J(c1) < J(c2)). The current J(c2) decreases monotonically with external magnetic field, while J(c1) exhibits a maximum at H*. For sufficient large magnetic fields the hysteresis disappears and J(c1) = J(c2) = Jc. In this high magnetic field region and for currents close to Jc the voltage appears as a result of the motion of separate vortices. With increasing current the moving vortices form,channels' with suppressed order parameter along which the vortices can move very fast. This leads to a sharp increase of the voltage. These 'channels' resemble in some respect the phase slip lines which occur at zero magnetic field. (C) 2004 Elsevier B.V. All rights reserved.

Abstract: On the basis of a simplified Hamiltonian for transition metal impurities in diluted magnetic semiconductors (DMS), the nature of ferromagnetism in p-type III-V DMS are investigated. Ferromagnetism is governed by the Anderson-Hubbard parameter for 3d electrons of Mn2+ and their strong hybridization with the hole carriers in the semiconducting medium. The origin of ferromagnetism in these materials has similarity with the Zener mechanism. From the energetically preferable parallel orientation of Mn spins the Curie temperature is calculated for GaAs:Mn. (C) 2002 Published by Elsevier Science B.V.