An Uneasy Match: Neoliberalism, Gentrification and Heritage Conservation in Bo-Kaap, Cape Town, South Africa

It is increasingly argued that gentrification is incorporated into public policy and the by-product of a range of contemporary neoliberal urban development policies intent on attracting investment capital. However, gentrification can also be the unintended outcome of well-meaning urban policy frameworks, such as urban densification, inner-city regeneration and urban heritage conservation but with arguably negative consequences. Focusing on Cape Town, the argument of this paper is that one of the outcomes of a neoliberalist approach to urban regeneration in the city centre is the impact it has on conserving the living and built environment heritage of the historic Bo-Kaap district. The last remaining inner-city neighbourhood that has not yet gentrified appears to be succumbing to this process. The outcome is a neighbourhood which is in economic and social flux and challenging the coherence of this once “indigenous” community.     

Recent Advances and Perspectives on Powder-Based Halide Perovskite Film Processing

Halide perovskites have undergone an impressive development and could be used in a wide range of optoelectronic devices, where some of them are already at the edge of commercialization, e.g., perovskite solar cells. Recently, interest in perovskites in powder form has increased, as for example, they are found to exhibit high stability and allow for easy production of large quantities. Accordingly, also the topic of processing thin and thick films on the basis of perovskite powders is currently gaining momentum. Here, perovskite powder can form the basis for both, typical wet and solvent-based processing approaches, as well as for dry processes. In this Progress Report, the recent developments of halide perovskites in powder form and of film processing approaches are summarized that are based on them. The advantages and opportunities of the different processing methods are highlighted, but their individual drawbacks and limitations are also discussed. Prospects are also pointed out and possible steps necessary to unlock the full potential of powder-based processing methods for producing high quality thick and thin perovskite layers in the future are discussed.     

Graphene Liquid Cells Assembled through Loop‐Assisted Transfer Method and Located with Correlated Light‐Electron Microscopy

Graphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high‐resolution, real‐time imaging of dynamic processes in water. Large‐scale implementation, however, is prevented by major difficulties in reproducing GLC fabrication. Here, a high‐yield method is presented to fabricate GLCs under millimeter areas of continuous graphene, facilitating efficient GLC formation on a TEM grid. Additionally, GLCs are located on the grid using correlated light‐electron microscopy (CLEM), which reduces beam damage by limiting electron exposure time. CLEM allows the acquisition of reliable statistics and the investigation of the most common shapes of GLCs. In particular, a novel type of liquid cell is found, formed from only a single graphene sheet, greatly simplifying the fabrication process. The methods presented in this work—particularly the reproducibility and simplicity of fabrication—will enable future application of GLCs for high‐resolution dynamic imaging of biomolecular systems.     

Synthesis of Al2O3/SiO2 nano‐nano composite ceramics under high pressure and its inverse Hall–Petch behavior

We report the synthesis of alumina/stishovite nano‐nano composite ceramics through a pressure‐induced dissociation in Al₂SiO₅ at a pressure of 15.6 GPa and temperatures of 1300°C‐1900°C. Stishovite is a high‐pressure polymorph of silica and the hardest known oxide at ambient conditions. The grain size of the composites increases with synthesis temperature from ~15 to ~750 nm. The composite is harder than alumina and the hardness increases with reducing grain size down to ~80 nm following a Hall–Petch relation. The maximum hardness with grain size of 81 nm is 23 ± 1 GPa. A softening with reducing grain size was observed below this grain size down to ~15 nm, which is known as inverse Hall–Petch behavior. The grain size dependence of the hardness might be explained by a composite model with a softer grain‐boundary phase.     

Observations on determinization of Büchi automata

The two determinization procedures of Safra and Muller–Schupp for Büchi automata are compared, based on an implementation in a program called OmegaDet.     

Systemic and pulmonary hemodynamics assessed with a lumped-parameter heart-arterial interaction model

Arterial pressure and flow result from the interaction between the (actively) ejecting ventricle and the (passive) arterial circulation. The main objective was to construct a model, accounting for this interaction, that is simple enough so that (i) model parameters can be derived from data measured in experimental and/or clinical conditions, and (ii) the model can be applied to support the analysis and interpretation of these data. It is demonstrated how an established conceptual model of ventricular function (the time-varying elastance) can be coupled to a four-element windkessel model of the arterial system to yield an elegant model of heart-arterial interaction. The coupling leads to a set of three ordinary differential equations. The model allows the study of the effect of changes in cardiac and/or arterial properties on arterial pressure and flow. As an illustration, cardiac and arterial model parameters are derived from measured experimental data in the systemic circulation of a pig and in the pulmonary circulation of a dog. It is evaluated how well measured cardiac and arterial function actually adhere to their assumed theoretical models (time-varying elastance and four-element windkessel model). It is further assessed how well the simple model of heart-arterial interaction describes systemic and pulmonary hemodynamics by comparing simulated and measured experimental data. The limitations and pitfalls of the model, as well as possible applications in the clinical field, are discussed.     

Exact closed-form geolocation for SAR interferometry

Exact closed-form algorithms for InSAR-derived digital elevation model (DEM) geolocation are described. They are based on the knowledge of orbit parameters and time/Doppler frequency coordinates of each SAR image, as well as of their interferometric phase. The proposed scheme gives a simple framework for deriving the geolocation accuracy     

Equivalence of cost generators for minimum cost flow phase unwrapping.

Phase unwrapping represents a crucial step in processing phase data obtained with techniques such as synthetic aperture radar interferometry, speckle interferometry, and magnetic resonance imaging. The so-called branch-cut approaches form an important class of phase unwrapping algorithms. In 1996, Costantini proposed to transform the problem of correctly placing branch cuts into a minimum cost flow problem [Proceedings of the Fringe '96 Workshop (European Space Agency, Munich, 1996), pp. 261-272]. The critical point of this new approach is to generate cost functions that have to represent all the a priori knowledge necessary for phase unwrapping. Any function transforming a priori knowledge into a cost function is called a cost generator. Several types of algorithms ranging from heuristic approaches to generators based on probability-theory interpretations were suggested. A problem arising from the growing diversity of algorithms is to find a criterion for the equivalence of different cost generators. Two cost generators are equivalent if they produce cost functions with the same minimal flow for every residue configuration on every image with all possible a priori knowledge. Comparing the results of different cost generators on test scenes can show only their non-equivalence. We solve this problem by proving the following mathematical classification theorem: Two cost generators are equivalent if and only if one can be transformed into the other by multiplication by a fixed constant.     

Embracing Innovation as Strategy: Corporate Venturing,Competence Building and Corporate Strategy Making

Large diversified companies companies do not have good track records in managing discontinuous change and in turning breakthrough innovations into long‐term growth and profit engines. Their existing technological capabilities tend to facilitate cognitive inertia, path dependency and low levels of experimentation. However, some companies seem to find a dynamic balance between exploitation and exploration, between path creation and path dependence. We focus on how these established firms manage that continuous change process, and more specifically we seek to answer how corporate strategy, competence building and new business development interact in rejuvenating a company. Furthermore, we investigate how these concepts are at play on an operational level by looking at corporate practices in large companies that have a track record of successful strategic rejuvenation.