Shakedown analysis of elastoplastic structures: A review of recent developments

Classical shakedown analysis rests on the assumptions of perfectly plastic, associative temperature-independent constitutive laws, negligible inertia and damping forces and negligible geometric effects.This paper provides a survey of the recent literature on the structural behaviour under variable repeated loads, with emphasis on the developments which relaxed some of the above assumptions, but preserved the character of generalization of limit analysis typical of the ‘classical’ shakedown theory and methods of analysis and design (in contrast to evolutive, step-by-step approaches of incremental plasticity).     

INFLUENCE OF RHEOLOGICAL PROPERTIES IN MASS TRANSFER PHENOMENA: SUPER CASE II SORPTION IN GLASSY POLYMERS

The sorption rate of swelling penetrants in glassy polymers has been considered as controlled both by the swelling kinetics and the penetrant diffusion through the swollen layer. The stress exerted on the glassy core at the moving boundary is the driving force for the swelling, and results from an osmotic stress and a differential swelling stress contribution. During the sorption process, the osmotic stress at the moving boundary decreases, due to the increasing diffusion resistance; the differential swelling stress, on the contrary, increases giving rise to an acceleration of the front velocity (Super Case II).

The particular case of negligible diffusion resistance in the swollen region is here considered in more detail. It is shown that the rheological properties of both swollen and glassy phases crucially enter the mass transport problem; thestress relaxation in the swollen region must be taken into account in order to obtain a thickness dependent Super Case 11 effect     

Design and Discovery of Plasmepsin II Inhibitors Using an Automated Workflow on Large‐Scale Grids

Novel and potent inhibitors of Plasmodium falciparum plasmepsin II were identified by post‐processing the results of a docking screening with BEAR, a recently reported procedure for the refinement and rescoring of docked ligands in virtual screening. FRET substrate degradation assays performed on the 30 most promising compounds resulted in 26 inhibitors with IC₅₀ values ranging from 4.3 nM to 1.8 μM .

     

Weaverbird: Topological Mesh Editing for Architects

Design and computation consultant Giulio Piacentino is the developer of WeaverBird. Here he describes how the plug-in ‘gives architects more geometric control and allows them to create complex surface structures that join in orderly ways, yet in arbitrary configurations’.     

Chemical characterisation of Thymus populations belonging from Southern Italy

The genus Thymus L. consists of many species of herbaceous perennials and sub-shrubs. A chemical characterisation of a collection of Thymus spp. originated from regions of Southern Italy was performed using GC and GC/MS. The accessions were collected from various natural habitats of the Basilicata and Puglia Regions and transferred into a new uniform environment. The study showed that amongst the 22 components of the oils the most recurrent ones were geraniol, thymol and α-terpinene followed by linalool, citral and trans-caryophillene. Cluster analysis led to the identification of two chemotypes: geraniol and thymol/α-terpinene; only a biotype remained separate from all others, probably because of its high content linalool (58%).     

Quercetin Administration Suppresses the Cytokine Storm in Myeloid and Plasmacytoid Dendritic Cells

Dendritic cells (DCs) can be divided by lineage into myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs). They both are present in mucosal tissues and regulate the immune response by secreting chemokines and cytokines. Inflammatory bowel diseases (IBDs) are characterized by a leaky intestinal barrier and the consequent translocation of bacterial lipopolysaccharide (LPS) to the basolateral side. This results in DCs activation, but the response of pDCs is still poorly characterized. In the present study, we compared mDCs and pDCs responses to LPS administration. We present a broad panel of DCs secreted factors, including cytokines, chemokines, and growth factors. Our recent studies demonstrated the anti-inflammatory effects of quercetin administration, but to date, there is no evidence about quercetin’s effects on pDCs. The results of the present study demonstrate that pDCs can respond to LPS and that quercetin exposure modulates soluble factors release through the same molecular pathway used by mDCs (Slpi, Hmox1, and AP-1).     

A 2D topology optimisation algorithm in NURBS framework with geometric constraints

In this paper, the solid isotropic material with penalisation (SIMP) method for topology optimisation of 2D problems is reformulated in the non-uniform rational BSpline (NURBS) framework. This choice implies several advantages, such as the definition of an implicit filter zone and the possibility for the designer to get a geometric entity at the end of the optimisation process. Therefore, important facilities are provided in CAD postprocessing phases in order to retrieve a consistent and well connected final topology. The effect of the main NURBS parameters (degrees, control points, weights and knot-vector components) on the final optimum topology is investigated. Classic geometric constraints, as the minimum and maximum member size, have been integrated and reformulated according to the NURBS formalism. Furthermore, a new constraint on the local curvature radius has been developed thanks to the NURBS formalism and properties. The effectiveness and the robustness of the proposed method are tested and proven through some benchmarks taken from literature and the results are compared with those provided by the classical SIMP approach.     

Sensory analysis integrated by palynological and physicochemical determinations plays a key role in differentiating unifloral honeys of similar botanical origins (Myrtaceae honeys from southern Spain)

Myrtaceae honeys produced in Sierra Morena (southern Spain, Andalusia) are obtained from both Eucalyptus camaldulensis and Myrtus communis, and honeys can be easily confused when classified as they come from the same botanical family. The characterisation was intended on the basis of their physicochemical, sensory and palynological properties. Cluster analysis (CA) and principal component analysis (PCA) allowed us to make a distinction between two honey profiles. The first one corresponds to the European sensory profile described for Eucalyptus unifloral honeys. The second profile, which sensory characteristics are absolutely different, has not been previously described. Classification of samples is proposed to be based on their pollen type and content and sensory attributes. Therefore, pollen type and content in E. camaldulensis and M. communis are required to distinguish Eucalyptus honey type from other honeys coming from Myrtaceae family. Sensory analysis identifies honey botanical source as well as palynological analysis: Eucalyptus sensory profile requires over 50% of E. camaldulensis and under 30% of M. communis pollen. Previously undefined sensory profile of myrtle honey is showed under 50% of E. camaldulensis and over 30% of M. communis pollen.     

Spatial agglomeration and productivity in Italy: A panel smooth transition regression approach

The paper analyses the nonlinearities in the impact of localization, diversity, urbanization and competition on firm‐level total factor productivity (TFP), using a large sample of Italian firms from 1999 to 2007. We adopt a panel smooth transition regression model, so that the TFP elasticities are free to vary smoothly across two or more extreme values. Results show that localization economies and Jacobian externalities materialize only for values of, respectively, intra‐industry agglomeration and extra‐sectoral diversity above a certain threshold. Local competition exerts a positive effect on productivity, even though the marginal impact shrinks at high levels of competition. We find instead no evidence of diseconomies of agglomeration.     

Read-out of soft X-ray contact microscopy microradiographs by focused ion beam/scanning electron microscope

A novel focused ion beam-based technique is presented for the read-out of microradiographs of Caenorhabditis elegans nematodes generated by soft x-ray contact microscopy (SXCM). In previous studies, the read-out was performed by atomic force microscopy (AFM), but in our work SXCM microradiographs were imaged by scanning ion microscopy (SIM) in a focused ion beam/scanning electron microscope (FIB/SEM). It allows an ad libitum selection of a sample region for gross morphologic to nanometric investigations, with a sequence of imaging and cutting. The FIB/SEM is less sensitive to height variation of the relief, and sectioning makes it possible to analyse the sample further. The SXCM can be coupled to SIM in a more efficient and faster way than to AFM. Scanning ion microscopy is the method of choice for the read-out of microradiographs of small multicellular organisms.