Novel Insight into the Intricate Shape of Flax Fibre Lumen

Plant fibres and especially flax can be distinguished from most synthetic fibres by their intricate shape and intrinsic porosity called lumen, which is usually assumed to be tubular. However, the real shape appears more complex and thus might induce stress concentrations influencing the fibre performance. This study proposes a novel representation of flax fibre lumen and its variations along the fibre, an interpretation of its origin and effect on flax fibre tensile properties. This investigation was conducted at the crossroads of complementary characterization techniques: optical and scanning electron microscopy (SEM), high-resolution X-ray microtomography (µCT) and mechanical tests at the cell-wall and fibre scale by atomic force microscopy (AFM) in Peak-Force Quantitative Nano-Mechanical property mapping (PF-QNM) mode and micromechanical tensile testing. Converging results highlight the difficulty of drawing a single geometric reference for the lumen. AFM and optical microscopy depict central cavities of different sizes and shapes. Porosity contents, varying from 0.4 to 7.2%, are estimated by high-resolution µCT. Furthermore, variations of lumen size are reported along the fibres. This intricate lumen shape might originate from the cell wall thickening and cell death but particular attention should also be paid to the effects of post mortem processes such as drying, retting and mechanical extraction of the fibre as well as sample preparation. Finally, SEM observation following tensile testing demonstrates the combined effect of geometrical inhomogeneities such as defects and intricate lumen porosity to drive the failure of the fibre.

The supramolecular landscape of growing human axons

During brain development, human axons must extend over great distances in a relatively short amount of time. How the subcellular architecture of the growing axon sustains the requirements for such rapid build-up of cellular constituents has remained elusive. Human axons have been particularly inaccessible to imaging at molecular resolution in a near-native context. Here we apply cryo-correlative light microscopy and electron tomography to growing axonal tracts from human cerebral organoids. Our data reveal a wealth of structural details on the arrangement of macromolecules, cytoskeletal components, and organelles in elongating axon shafts. In particular, the intricate shape of the endoplasmic reticulum is consistent with its role in fulfilling the high demand for lipid biosynthesis to support growth. Furthermore, the scarcity of ribosomes within the growing shaft suggests limited translational competence during expansion of this compartment. These data provide an unprecedented resource and reveal a molecular architecture that helps explain the unique biology of growing human axons.

Evaluation of Draw Beads Influence on Intricate Shape Stamping Drawing Process

Paper concerns evaluation of influence of shape, size and location of rectangular and semicircular draw beads on sheet-metal forming process. For analysis the simulations of forming process of selected two types of intricate shape stampings with similar ground plan and with approximately the same height from steel strip DC04 with the use of models of optimal blanks made by BSE (Blank Size Engineering) modul of simulation program Dynaform 5.7 were carried out. From simulations of forming process in simulation program Dynaform 5.7 followed that the most suitable is drawing without use of draw beads because cracks in stamping bottom corners do not arise. In the case of undesirable secondary waviness in the walls of intricate shape stamping the drawing with draw beads could be used but it would be necessary to increase the radius at the bottom of both stampings alternatively to choose another material with higher formability.

Prototyping as a Tool for Rapid Development of Components for Sporting Equipment

The purpose of this article is to demonstrate the potential of hydroforming process combined with the Engineering Design Science (EDS) in single piece production of a technical product. The chosen demonstration product for this integrated approach is a ski riser for extreme carving. Its load-bearing base is an intricate-shape part that is well suited for modified hydroforming process in an isostatic press. In order to reduce production costs, rapid prototyping and rapid tooling methods were used.

Analysis of Process Parameters of Plasma Arc Cutting of Stainless Steel Using Taguchi Method

Plasma Arc Machining is one of the most important non conventional machining method used in fabrication industries because of its high accuracy, ability to machine any hard material, ability to produce any intricate shape and better finish. In the present investigation, plasma arc cutting of stainless steel (316L) materials has been carried out using plasma arc cutting machine. The optimization of process has been carried out using Taguchi method of design of experiment.