The influence of tDCS on perceived bouncing/streaming

Processing ambiguous situations is a constant challenge in everyday life and sensory input from different modalities needs to be integrated to form a coherent mental representation on the environment. The bouncing/streaming illusion can be studied to provide insights into the ambiguous perception and processing of multi-modal environments. In short, the likelihood of reporting bouncing rather than streaming impressions increases when a sound coincides with the moment of overlap between two moving disks. Neuroimaging studies revealed that the right posterior parietal cortex is crucial in cross-modal integration and is active during the bouncing/streaming illusion. Consequently, in the present study, we used transcranial direct current stimulation to stimulate this brain area. In the active stimulation conditions, a 9 cm2 electrode was positioned over the P4-EEG position and the 35 cm2 reference positioned over the left upper arm. The stimulation lasted 15 min. Each participant did the bouncing/streaming task three times: before, during and after anodal or sham stimulation. In a sample of N = 60 healthy, young adults, we found no influence of anodal tDCS. Bayesian analysis showed strong evidence against tDCS effects. There are two possible explanations for the finding that anodal tDCS over perceptual areas did not modulate multimodal integration. First, upregulation of multimodal integration is not possible using tDCS over the PPC as the integration process already functions at maximum capacity. Second, prefrontal decision-making areas may have overruled any modulated input from the PPC as it may not have matched their decision-making criterion and compensated for the modulation

Characterising existing buildings as material banks (E-BAMB) to enable component reuse

As-built records for existing buildings tend to be poor. Components that make up the existing building stock must be better characterised to prevent them becoming waste. The first record of materials in an existing building is often the waste report, which classifies materials for waste management and gathers information after the opportunity for higher-value reuse of components has passed. Policy at various levels aims to increase reuse, but an understanding of ‘existing buildings as material banks’ (E-BAMB) is a necessary precursor to overcoming other barriers. This paper reviews the current means of understanding E-BAMB and identifies its shortfalls. This analysis leads to the conception of a strategy in which the various approaches are organised as an information system. The future role of technology and mandatory provision of E-BAMB information at the planning stage are explored. The proposed system would enable specifiers, manufacturers and academics to assess the wealth of materials that can be reused, repurposed or upcycled in new projects or businesses. This does not guarantee that actual reuse will occur, as financial, technical and legal barriers may remain. However, it creates the context for assessing secondary components against their virgin equivalents and the enabling conditions for new circular business models

Nonuniform friction-area dependency for antimony oxide surfaces sliding on graphite

Cataloged from PDF version of article.We present frictional measurements involving controlled lateral manipulation of antimony nanoparticles on graphite featuring atomically smooth particle-substrate interfaces via tapping- and contact-mode atomic force microscopy. As expected from earlier studies, the power required for lateral manipulation as well as the frictional forces recorded during the manipulation events exhibit a linear dependence on the contact area over a wide size range from 2000 nm2 to 120 000 nm2. However, we observe a significant and abrupt increase in frictional force and dissipated power per contact area at a value of about 20 000 nm2, coinciding with a phase transition from amorphous to crystalline within the antimony particles. Our results suggest that variations in the structural arrangement and stoichiometry of antimony oxide at the interface between the particles and the substrate may be responsible for the observed effect. © 2013 American Physical Society

Interdigitated back contact silicon heterojunction solar cells Towards an industrially applicable structuring method

We report on the investigation and comparison of two different processing approaches for interdigitated back contacted silicon heterojunction solar cells our photolithography based reference procedure and our newly developed shadow mask process. To this end, we analyse fill factor losses in different stages of the fabrication process. We find that although comparably high minority carrier lifetimes of about 4 ms can be observed for both concepts, the shadow masked solar cells suffer yet from poorly passivated emitter regions and significantly higher series resistance. Approaches for addressing the observed issues are outlined and first solar cell results with efficiencies of about 17 and 23 for shadow masked and photolithographically structured solar cells, respectively, are presente

Quantification of Spatial Parameters in 3D Cellular Constructs Using Graph Theory

Multispectral three-dimensional (3D) imaging provides spatial information for biological structures that cannot be measured by traditional methods. This work presents a method of tracking 3D biological structures to quantify changes over time using graph theory. Cell-graphs were generated based on the pairwise distances, in 3D-Euclidean space, between nuclei during collagen I gel compaction. From these graphs quantitative features are extracted that measure both the global topography and the frequently occurring local structures of the “tissue constructs.” The feature trends can be controlled by manipulating compaction through cell density and are significant when compared to random graphs. This work presents a novel methodology to track a simple 3D biological event and quantitatively analyze the underlying structural change. Further application of this method will allow for the study of complex biological problems that require the quantification of temporal-spatial information in 3D and establish a new paradigm in understanding structure-function relationships

The Marco Gonzalez Maya site, Ambergris Caye, Belize: assessing the impact of human activities by examining diachronic processes at the local scale

Research at the Maya archaeological site of Marco Gonzalez on Ambergris Caye in Belize is socio-ecological because human activities have been a factor in the formation and fluctuation of the local marine and terrestrial environments over time. The site is one of many on Belize's coast and cayes that exhibit anomalous vegetation and dark-coloured soils. These soils, although sought for cultivation, are not typical 'Amazonian Dark Earths' but instead are distinctive to the weathering of carbonate-rich anthropogenic deposits. We tentatively term these location-specific soils as Maya Dark Earths. Our research seeks to quantify the role of human activities in long-term environmental change and to develop strategies, specifically Life Cycle Assessment (LCA), that can be applied to environmental impact modelling today

Stability Assessment of p i n Perovskite Photovoltaic Mini Modules Utilizing Different Top Metal Electrodes

Long term stability is one of the major challenges for p i n type perovskite solar modules PSMs . Here, we demonstrate the fabrication of fully laser patterned series interconnected p i n perovskite mini modules, in which either single Cu or Ag layers are compared with Cu Au metal bilayer top electrodes. According to the scanning electron microscopy measurements, we found that Cu or Ag top electrodes often exhibit flaking of the metal upon P3 top contact removal laser patterning. For Cu Au bilayer top electrodes, metal flaking may cause intermittent short circuits between interconnected sub cells during operation, resulting in fluctuations in the maximum power point MPP . Here, we demonstrate Cu Au metal bilayer based PSMs with an efficiency of 18.9 on an active area of 2.2 cm2 under continuous 1 sun illumination. This work highlights the importance of optimizing the top contact composition to tackle the operational stability of mini modules, and could help to improve the feasibility of large area module deployment for the commercialization of perovskite photovoltaic