Melt electro-written scaffolds with box-architecture support orthogonally-oriented collagen

Melt Electro-Writing (MEW) is a state-of-the-art technique that supports fabrication of 3D, precisely controlled and reproducible fiber structures. A standard MEW scaffold design is a box-structure, where a repeat layer of 90° boxes is produced from a single fiber. In 3D form (i.e., multiple layers), this structure has the potential to mimic orthogonal arrangements of collagen, as observed in the corneal stroma. In this study, we determined the response of human primary corneal stromal cells and their deposited fibrillar collagen (detected using a CNA35 probe) following 6-weeks in vitro culture on these box-structures made from poly(ε-caprolactone). Comparison was also made to glass substrates (topography-free) and electrospun poly(ε-caprolactone) fibers (aligned topography). Cell orientation and collagen deposition were non-uniform on glass substrates. Electrospun scaffolds supported an excellent parallel arrangement of cells and deposited collagen to the underlying architecture of aligned fibers, but there was no evidence of bidirectional collagen. In contrast, MEW scaffolds encouraged the formation of a dense, interconnected cellular network and deposited fibrillar collagen layers with a distinct orthogonal-arrangement. Collagen fibrils were particularly dominant through the middle layers of the MEW scaffolds’ total thickness and closer examination revealed these fibrils to be concentrated within the pores’ central regions. With the demand for donor corneas far exceeding the supply - leaving many with visual impairment - the application of MEW as a potential technique to recreate the corneal stroma with spontaneous, bidirectional collagen organization warrants further study.

The effect of modal properties of crash box structures with trigger mechanisms towards the crashworthiness by using finite element analysis

In the automotive structure, there are different components that utilise aluminium alloy (AA) sheets and it is used widely in the car body-in-white which comprise bumpers and the crash box structure at the front end of the car which specifically designed to withstand the event of collision. As the structures are also experiencing dynamic loading, it were also a concern for the structures to show satisfied modal properties. In this study, the modal properties of the crash box structures are investigated along with the effect of the modal properties towards the crashworthiness behaviour of the structure itself with the approach of finite element analysis. Experimental modal analysis was also done to further validating the finite element analysis of the modal properties. Three different designs of trigger mechanisms are applied towards the crash box structure to observe on both findings. For the connector element, equivalent nodes of both parts of the crash box structures are used. For the results, the correlation from both findings did show that the presence of trigger mechanism did decreased the magnitude of natural frequencies as well as the mode shape as shown by crash box type 3 by 9.50% and for the crashworthiness output, the crashworthiness behaviour of the crash box with trigger mechanisms were better in term of the collisions phases indicated by the primary peak force and the secondary peak force from the force-displacement curve as also shown by crash box structure type 3 with the percentage of 22.59%. The study does shows that the stiffness and mass distribution due to the presence of trigger mechanism do affect the modal properties of a structure as well as its crashworthiness output.

Queen’s Idiolect

This chapter documents the key characteristics of Queen’s idiolect as pertaining to harmonic gestures and structure, textural layers and the sound-box, and arrangement gestures. It is argued that the harmonic structures of Queen’s songs are defined through their consistent movement between tonic and dominant chords, which is embellished through rich chromatic gestures. The textures of Queen’s songs sit in one of five archetypal combinations involving piano, electric guitars, bass guitar, and drums, which are enhanced through vocals, lead guitars, synthesisers, and non-rock instruments. Queen’s sound-box structures are timbrally balanced and often present some form of dynamic movement of sounds in a virtual space. The different idiolect traits allow one to understand most of Queen’s songs either in terms of articulating a common compositional strategy (akin to a form of musical logic) or presenting sonic patterns that are like musical fingerprints.

Non-radial two-stage network DEA model to estimate returns to scale

Purpose As returns to scale (RTS) describes the long run connection of the changes of outputs relative to increases in the inputs, the purpose of this study is to answer the following questions: If the proportionate changes exist in the inputs, what is the rate of changes in outputs with respect to the inputs’ variations in the two-stage networks over the long term? How can the authors investigate quantitative RTS in the two-stage networks? In other words, the purpose of this research is to introduce a different approach to estimate the performance, RTS and scale economies (SE) in network structures. Design/methodology/approach This paper proposes a novel non-radial approach based on data envelopment analysis to analyze the performance and to investigate RTS and SE in two-stage processes. Findings The findings show that the range adjusted measure (RAM)/RTS approach can identify reference sets for overall systems and each stage. In addition, the models presented in this paper can classify decision-making units and determine the increasing/decreasing trends of RTS. Originality/value The majority of previous RTS studies have been examined in black-box structures and have been discussed in a radial framework. Therefore, in this study, RTS and SE in the two-stage networks are dealt with using an extended RAM approach. Actually, the efficiency and RTS for each stage and the overall model are calculated using the proposed technique.

Mapping of scatter in fatigue life assessment of welded structures—a round-robin study

A round-robin study has been carried out within a national project in Sweden with the addition of an international participant, where several industrial partners and universities are participating. The project aims to identify variation and sources of variation in welding production, map scatter in fatigue life estimation, and define and develop concepts to reduce these, in all steps of product development. The participating organisations were asked to carry out fatigue life assessment of welded box structures, which is a component in load-carrying structures. The estimations of fatigue life have also been compared with fatigue test results. Detailed drawings, loads and material data were also given to the participants. The participants were supposed to use assessment methods based on global and local stresses using the design codes or recommendations they currently use in-house. Differences were identified between both methods and participants using the same codes/recommendations. Applicability and conditions from the cases in the codes were also identified to be differently evaluated between the participants. It could be concluded that for the applied cases the nominal stress method often overestimated the fatigue life and had a high scatter in the estimations by different participants. The effective notch method is conservative in comparison to the life of tested components with little scatter between the results derived by the participants.

Block-box structures load-bearing capacity under special loads

Block-box structures today are widely used in construction. Their main features are mobility, lightness and the possibility of assembling block-boxes for any technological purpose. Block-boxes are used in the arrangement of oil and gas fields, settlements and cities where it is necessary to carry out construction in a short period of time or where there is no industrial infrastructure. When designing, it is often necessary to take into account special loads (earthquake or explosive), which significantly affect the applied structural solutions. In this paper, the load-bearing steel structures of block-boxes of various configurations and sizes under the influence of special types of loads are considered. Numerical research, analysis and improvement of structural solutions are carried out.