Creating Macroscopes with Technology and Analytics: New Possibilities in Our Lives – The Important Role of Tomorrow’s Mathematics Professionals (Abstract)

Our world is increasingly computerized, interconnected, and instrumented with sensors. Massive amounts of data are being captured in computer systems about our natural environment and man-made engineered structures, processes, and systems. But it is necessary to make sense out of all this data. With new computer methods computers can in effect become macroscopes, enabling us to see the world portrayed by our data

In situ ultrafine force measurement with nanowire based cantilevers in SEM

In nanomechanics the measurement of ultrafine forces becomes increasingly important for unravelling subtle details of elastic and plastic deformation processes. In particular, achieving high force resolution in combination with in situ imaging is a major challenge which is becoming exceedingly difficult with conventional methods. In this work, we introduce a novel systematic method to measure ultrafine forces using well-defined nanowires as cantilever beams in situ in the Scanning Electron Microscope (SEM). Forces can be measured variably in the range from micro-newtons (mN) down to femto-newtons (fN), depending on the chosen reference nanowire. The reference wires are picked with a manipulator tip without the use of FIB (see Figure 1 a). Please click Additional Files below to see the full abstract

Pattern formation in fluidized and vibrated beds: experimental and computational insights

Gas-solid fluidized beds can form dynamical patterns when fluidized with a pulsed flow (1). This phenomenon excels as a method to structure fluidized bed dynamics and has great potential to facilitate fluidized bed scale-up (2,3) and validate computational fluid-dynamics models (4); however, it has remained highly unexplored since first discovered and it is far from being understood. Moreover, Computational Fluid Dynamics (CFD) have not been able so far to clearly reproduce the experimental patterns (4,5), even though discrete element model (DEM) studies suggest some organization of the bubbles (5). Patterns appear as a result of the collective behavior of granular matter when subject to an oscillating excitation, and can also be observed in vertically vibrated beds (6). In bubbling quasi-2D beds, patterns manifest themselves as hexagonal bubble configurations, where bubbles are generated in alternating positions at every pulse. In shallow 3D beds, independently of the type of excitation¾vibration or pulsed flow¾the surface is decorated with stripes and squares (Fig. 1) in which the characteristic length-scale decreases with the frequency of the oscillating force. Contrary to pattern formation in fluidized beds, patterns in vibrated systems have been extensively studied. The knowledge developed in this field can be used as a basis to understand the behavior of fluidized granular matter. In this contribution, we show the first successful CFD simulation of an experimental bubble pattern in a gas-solid fluidized bed, which was obtained with DEM (Fig. 2). We also discuss our last insights about pattern formation in fluidized beds obtained by comparing experimental pattern formation in vibrated and fluidized systems. Gas-solid fluidized beds can form dynamical patterns when fluidized with a pulsed flow (1). This phenomenon excels as a method to structure fluidized bed dynamics and has great potential to facilitate fluidized bed scale-up (2,3) and validate computational fluid-dynamics models (4); however, it has remained highly unexplored since first discovered and it is far from being understood. Moreover, Computational Fluid Dynamics (CFD) have not been able so far to clearly reproduce the experimental patterns (4,5), even though discrete element model (DEM) studies suggest some organization of the bubbles (5). Patterns appear as a result of the collective behavior of granular matter when subject to an oscillating excitation, and can also be observed in vertically vibrated beds (6). In bubbling quasi-2D beds, patterns manifest themselves as hexagonal bubble configurations, where bubbles are generated in alternating positions at every pulse. In shallow 3D beds, independently of the type of excitation¾vibration or pulsed flow¾the surface is decorated with stripes and squares (Fig. 1) in which the characteristic length-scale decreases with the frequency of the oscillating force. Contrary to pattern formation in fluidized beds, patterns in vibrated systems have been extensively studied. The knowledge developed in this field can be used as a basis to understand the behavior of fluidized granular matter. In this contribution, we show the first successful CFD simulation of an experimental bubble pattern in a gas-solid fluidized bed, which was obtained with DEM (Fig. 2). We also discuss our last insights about pattern formation in fluidized beds obtained by comparing experimental pattern formation in vibrated and fluidized systems. Gas-solid fluidized beds can form dynamical patterns when fluidized with a pulsed flow (1). This phenomenon excels as a method to structure fluidized bed dynamics and has great potential to facilitate fluidized bed scale-up (2,3) and validate computational fluid-dynamics models (4); however, it has remained highly unexplored since first discovered and it is far from being understood. Moreover, Computational Fluid Dynamics (CFD) have not been able so far to clearly reproduce the experimental patterns (4,5), even though discrete element model (DEM) studies suggest some organization of the bubbles (5). Patterns appear as a result of the collective behavior of granular matter when subject to an oscillating excitation, and can also be observed in vertically vibrated beds (6). In bubbling quasi-2D beds, patterns manifest themselves as hexagonal bubble configurations, where bubbles are generated in alternating positions at every pulse. In shallow 3D beds, independently of the type of excitation¾vibration or pulsed flow¾the surface is decorated with stripes and squares (Fig. 1) in which the characteristic length-scale decreases with the frequency of the oscillating force. Contrary to pattern formation in fluidized beds, patterns in vibrated systems have been extensively studied. The knowledge developed in this field can be used as a basis to understand the behavior of fluidized granular matter. In this contribution, we show the first successful CFD simulation of an experimental bubble pattern in a gas-solid fluidized bed, which was obtained with DEM (Fig. 2). We also discuss our last insights about pattern formation in fluidized beds obtained by comparing experimental pattern formation in vibrated and fluidized systems. Please click Additional Files below to see the full abstract

Multiscale modeling of pattern formation in pulsed fluidized beds: Continuum and discrete approaches

It has been demonstrated experimentally that, under certain experimental conditions, a periodic flow can induce the formation of sub-harmonic bubble patterns in gas-solid fluidized beds (1). In spite of their potential for structuring and scaling up fluidized beds (2), very little progress has been achieved so far and the pattern formation mechanism still remains largely unknown. In quasi-2D bubbling beds, bubbles rise forming hexagonal configurations, alternating their position at every pulse, with a characteristic length independent of bed dimension. The formation of patterns is not just a singular feature of the dynamics, but emerges as a consequence of extensive coupling between multi-scale physical phenomena. The striking visual manifestation and the complexity of the underlying physics make pattern formation excel as a validation tool for computational fluid dynamics (CFD) models (3). Over the last two decades, CFD codes have been successfully used in modeling and investigating fluidization. Granular media are commonly modeled at two different scales, namely by local averaging (4) and individual tracking (5). Both can predict various fluidization behaviors satisfactorily. However, it is remarkable that, so far, CFD has not been able to convincingly reproduce the experimental patterns of bubbles (6) In this work, we show the results of our study comparing different modeling strategies, using both a two-fluid model and a discrete element method, in terms of their ability to reproduce the experimentally witnessed patterns (Fig. 1). We also discuss our recent insights in the dominating parameters and closures necessary to capture the underlying physics of this fluidized state correctly. Please click Additional Files below to see the full abstract

Copper-containing mesoporous bioactive glass promotes angiogenesis in an in vivo zebrafish model

The osteogenic and angiogenic responses of organisms to the ionic products of degradation of bioactive glasses (BGs) are being intensively investigated. The promotion of angiogenesis by copper (Cu) has been known for more than three decades. This element can be incorporated to delivery carriers, such as BGs, and the materials used in biological assays. In this work, Cu-containing mesoporous bioactive glass (MBG) in the SiO2-CaO-P2O5 compositional system was prepared incorporating 5% mol Cu (MBG-5Cu) by replacement of the corresponding amount of Ca. The biological effects of the ionic products of MBG biodegradation were evaluated on a well-known endothelial cell line, the bovine aorta endothelial cells (BAEC), as well as in an in vivo zebrafish (Danio rerio) embryo assay. The results suggest that ionic products of both MBG (Cu free) and MBG-5Cu materials promote angiogenesis. In vitro cell cultures show that the ionic dissolution products of these materials are not toxic and promote BAEC viability and migration. In addition, the in vivo assay indicates that both exposition and microinjection of zebrafish embryos with Cu free MBG material increase vessel number and thickness of the subintestinal venous plexus (SIVP), whereas assays using MBG-5Cu enhance this effect.The authors gratefully acknowledge the financial support provided by the Andalusian Ministry of Economy, Science and Innovation (Proyectos Excelencia Grants no. P10-CTS-6681 and no. P12-CTS-1507) and Spanish Ministry of Economy and Competitivity (BIO2014-56092-R). LBRS acknowledges the CONACYT-Mexico Fellowship PhD Program

F-actin-rich contractile endothelial pores prevent vascular leakage during leukocyte diapedesis through local rhoA signaling in vivo

During immune surveillance and inflammation, leukocytes exit the vasculature through transient openings in the endothelium without causing plasma leakage. However, the exact mechanisms behind this intriguing phenomenon are still unknown. Here we report that maintenance of endothelial barrier integrity during leukocyte diapedesis requires local endothelial RhoA cycling. Endothelial RhoA depletion in vitro or Rho inhibition in vivo provokes neutrophil-induced vascular leakage that manifests during the physical movement of neutrophils through the endothelial layer. Local RhoA activation initiates the formation of contractile F-actin structures that surround emigrating neutrophils. These structures that surround neutrophil-induced endothelial pores prevent plasma leakage through actomyosin-based pore confinement. Mechanistically, we found that the initiation of RhoA activity involves ICAM-1 and the Rho GEFs Ect2 and LARG. In addition, regulation of actomyosin-based endothelial pore confinement involves ROCK2b, but not ROCK1. Thus, endothelial cells assemble RhoA-controlled contractile F-actin structures around endothelial pores that prevent vascular leakage during leukocyte extravasation