Equivalent in-plane elastic modulus of honeycomb sandwich in the direction of cell vertical wall

The equivalent in-plane elastic modulus [Formula: see text] of a honeycomb sandwich in the direction of cell vertical wall can be assessed by the law of mixture from the modulus of face sheet [Formula: see text] and the equivalent modulus of honeycomb core [Formula: see text]. However, significant errors as large as 40% can be made depending on material and geometry parameters, when the used [Formula: see text] is obtained from a cellular model of core alone without considering the skin effect of face sheet. The main reason of the error is that the rigidity to deformation of y-direction is different greatly between the vertical cell wall of core and inclined cell wall of core. In the present paper, an analytical model is proposed to assess [Formula: see text] of honeycomb sandwich with considering the interference effect of the core with the face sheet. In the proposed model, the influence of the face sheet rigidity on [Formula: see text] is taken into account. The results demonstrate that the contribution of the core to [Formula: see text] is also dependent on the face sheet rigidity significantly. The validity of presented model is verified by comparing the results with numerical results of FEA.

High-Resolution Imaging of Bacterial Spatial Organization with Vertical Cell Imaging by Nanostructured Immobilisation (VerCINI)

Light microscopy is indispensable for analysis of bacterial spatial organization. However, imaging in bacteria is difficult due to their small sizes and the fact that most species are non-spherical, meaning they typically lie horizontally on a microscope coverslip. This is especially problematic when considering that many essential bacterial processes—such as cell division—occur along the short axes of these cells, and so are viewed side-on by standard microscopy. We recently developed a pair of methods to overcome this problem by forcing cells to stand vertically during imaging, named VerCINI (Vertical Cell Imaging by Nanostructured Immobilisation) and µVerCINI (Microfluidic VerCINI). The concept behind both methods is that cells are imaged while confined vertically inside cell traps made from a nanofabricated mould. By doing so, the short axes of the cells are rotated parallel to the microscope imaging plane and are imaged with high resolution. μVerCINI combines the vertical cell confinement with microfluidics so that vertical imaging can be done during fluid exchange, such as during antibiotic perturbations. Here, we provide a practical guide to implementing both VerCINI and µVerCINI, with detailed protocols and experience-based tips so that interested researchers can easily use one or both imaging methods to complement their current approaches.

In-plane compression modulus and strength of Nomex honeycomb cores

The stress-strain response and deformation mechanism of a range of Nomex honeycomb cores tested under in-plane compression has been examined experimentally. The cores with a thin wall displayed extensive bending deformation of the cell walls inclined to the horizontal (loading is vertical) and failed in bending. The cores with thicker walls failed by a shear-type instability of the cells indicated by tilting of vertical cell wall segments. The failure strain decreased with increasing core density. The modulus and compressive strength of the core were compared to micromechanical predictions. Normalized modulus and strength values varied between the various cores. The average modulus and strength results allow backing out of the modulus and bending strength of the Nomex paper. The results were in reasonable agreement with published tensile test results and composite micromechanics.

Experimental Investigation of Photovoltaic Partial Shading Losses under Different Operation Conditions

The partial shading conditions have a significant effect on the performance of Photovoltaic system and the ability of delivering energy. In this study, the impact of different partial shading on the mono crystalline (88W) PV module performance was investigated in this study. Horizontal string, vertical string, and single cell shading at different percentage of shading area have been studied. It is found that the horizontal string shading is more severe on the efficiency of the PV panel. In contrast, the efficiency of PV panel with cellular and vertical cell shading was less during the tests. The experimental results showed that the power losses were 99.8%, 66% and 56.8 % for horizontal, cellular and vertical shading respectively via applied non transparent material as shading element by 100% of shading area at 500 W/m2. Moreover, transparent material used to shade whole module horizontally, different shading area and different radiation level applied to find electrical characteristics of the module under these conditions. The results show that at 800W/m2 of irradiation levels and no shading condition the power was 68.6W, by increase shading area by 20% in each step, the power reducing by 44.94, 47.58, 49.42, 50.57 and 52.4% in compared with their initial value at no shading condition.

Directed vertical cell migration via bifunctionalized nanomaterials in 3D step-gradient nanocomposite hydrogels

Step-gradient scaffolds promote healthy cell migration, while inhibit the migration of cancerous cells in the XZ plane of the 2GradNS.

Expanded Douglas–Peucker Polygonal Approximation and Opposite Angle-Based Exact Cell Decomposition for Path Planning with Curvilinear Obstacles

The Expanded Douglas–Peucker (EDP) polygonal approximation algorithm and its application method for the Opposite Angle-Based Exact Cell Decomposition (OAECD) are proposed for the mobile robot path-planning problem with curvilinear obstacles. The performance of the proposed algorithm is compared with the existing Douglas–Peucker (DP) polygonal approximation and vertical cell decomposition algorithm. The experimental results show that the path generated by the OAECD algorithm with EDP approximation appears much more natural and efficient than the path generated by the vertical cell decomposition algorithm with DP approximation.

Epithelial invagination by vertical telescoping

Epithelial bending is a fundamental process that shapes organs during development. All currently known mechanisms involve cells locally changing shape from columnar to wedge-shaped. Often this shape change occurs by cytoskeletal contraction at cell apices (“apical constriction”) but mechanisms such as basal nuclear positioning (“basal wedging”) or extrinsic compression are also known. Here we demonstrate a completely different mechanism which occurs without cell wedging. In mammalian salivary glands and teeth, we show that initial invagination occurs through coordinated vertical cell movement. Specifically, we show that cells towards the periphery of the placode move vertically upwards while their more central neighbours move downwards to create the invagination. We further show that this occurs by active cell-on-cell migration: outer cells migrate with an apical leading edge protrusion, depressing the central cells to “telescope” the epithelium downwards into the underlaying mesenchyme. Cells remain basally attached to the underlying lamina while their apical protrusions are dynamic and planar polarised centripetally. These protrusions depend on the actin cytoskeleton, and inhibition of the branching molecule Arp2/3 inhibits them and the invagination. FGF and Hedgehog morphogen signals are also required, with FGF providing a directional cue. These findings show that epithelial bending can be achieved by novel morphogenetic mechanism of coordinated cell rearrangement quite distinct from previously recognised invagination processes.