Search results for "Elastic"

Improving surface detection on nanoindentation of compliant materials

2010

Nanoindentation is a versatile tool for monitoring mechanical properties on a local scale. Accurate knowledge of a contact area, and therefore an initial contact, is however necessary for translating the force curve into sample mechanical properties. It is shown that methods for sensing an initial contact by depth sensing instruments (DSI) may be severely in error for compliant materials. With the hardware adopted in this work, the threshold is determined by the elastic modulus; hence the error potentially increases if the material becomes more compliant. A simple method is therefore suggested to determine with accuracy the initial contact on compliant materials whereby the surface contact …

Chitosomes as drug delivery systems for C-phycocyanin: preparation and characterization.

2010

The aim of this work was to investigate chitosomes, i.e. liposomes coated by a polyelectrolyte complex between chitosan (CH) and xantan gum (XG), as potential delivery system for oral administration of the protein C-phycocyanin. To this purpose several CH-XG-microcomplexes were prepared in aqueous lactic acid at different chitosan-xanthan gum percent ratios and rheological properties of the microcomplexes were studied to analyse the contribution of chitosan and xanthan gum in the reaction of microcomplexation. After establishing the best microcomplexes, chitosomes were prepared by coating C-phycocyanin loaded liposomes with the CH-XG hydrogels using spray-drying or freeze-drying. The chitos…

Long Term Outcome after Application of the Angio-Seal Vascular Closure Device in Minipigs

2016

PLoS one 11(9), e0163878 (2016). doi:10.1371/journal.pone.0163878

Photoelastic Analysis of Partially Occluded Objects With an Integral-Imaging Polariscope

2014

Polariscopes are the basic instruments used for the analysis of the stress state of transparent materials. Polarized light passing through a 3D object carries the integrated effect of the stress field along the light path. Therefore, conventional polariscopes are not able to discern the stress state of objects involving multiple plates with mutual occlusions. In this paper we propose a novel experimental system for three-dimensional stress analysis based on the combination of a polariscope and Synthetic Aperture Integral Imaging technique. Experimental results show the system's ability to recover the information of the stress distribution of a set of plates located at different depths havin…

The thermoelasticity problem of axisymmetric solids with a thermal conductivity linearly depending on the temperature and on the volumetric strain

2000

Film blowing of silane-modified polyethylene

2009

The grafting of vinyltriethoxysilane (VTES) onto polyethylene (PE) with the help of small amounts of peroxides was investigated to film-blow these modified materials. The degree of crosslinking was kept very low to achieve good melt processability and improved mechanical properties. The possibility of obtaining modified PE films with improved properties and regularly distributed crosslinking with a single processing step demonstrates the uniqueness of this study. The additive concentration was established through preliminary studies; with a batch mixer, it was possible to process the modified PE in the film-blowing operation. Water treatment of the modified films after film blowing allowed …

Investigation of the Thermomechanical Response of Cyclically Loaded NiTi Alloys by Means of Temperature Frequency Domain Analyses

2021

Nickel–Titanium (NiTi) shape memory alloys subjected to cyclic loading exhibit reversible temperature changes whose modulation is correlated with the applied load. This reveals the presence of reversible thermomechanical heat sources activated by the applied stresses. One such source is the elastocaloric effect, accounting for the latent heat of Austenite–Martensite phase transformation. It is, however, observed that when the amplitude of cyclic loads is not sufficient to activate or further propagate this phase transformation, the material still exhibits a strong cyclic temperature modulation. The present work investigates the thermomechanical behaviour of NiTi under such low-amplitude cyc…

Towards modern understanding of the Achilles tendon properties in human movement research

2023

The Achilles tendon (AT) is the strongest tendon in humans, yet it often suffers from injury. The mechanical properties of the AT afford efficient movement, power amplification and power attenuation during locomotor tasks. The properties and the unique structure of the AT as a common tendon for three muscles have been studied frequently in humans using in vivo methods since 1990's. As a part of the celebration of 50 years history of the International Society of Biomechanics, this paper reviews the history of the AT research focusing on its mechanical properties in humans. The questions addressed are: What are the most important mechanical properties of the Achilles tendon, how are they stud…

Nonlinear finite element analysis of no-tension masonry structures

1995

A numerical approach for structural analysis of masonry walls in plane stress conditions is presented. The assumption of a perfectly no-tension material (NTM) constitutive model, whose relevant equations are in the form of classical rate-independent associated flow laws of elastoplastic material, allows one to adopt numerical procedures commonly used in computational plasticity. An accuracy analysis on the integration algorithm employed in the solution of constitutive relations has been carried out. The results obtained for some relevant case-studies and their comparison with data, available in the literature show the effectiveness of the proposed method.

La stereotomia nella cattedra di Architettura statica di Carlo Giachery

2014

La scuola di architettura di Palermo, sin dalla sua fondazione nel 1779, con la creazione della cattedra di Architettura civile affidata a Giuseppe Venanzio Marvuglia, era divenuta inevitabilmente il luogo di verifica e talvolta di esplorazione dei temi legati alla pratica professionale e, quindi, all’arte del costruire. Giachery, Professore di Architettura statica e civile dal 1837 al 1865, è il primo ad avvertire, da docente, la crisi profonda del sistema didattico della scuola di architettura di Palermo isterilita dalla ricerca di astratte idealità neoclassiche e straniatasi dal processo evolutivo della cultura architettonica europea dopo la morte dei “maestri” Marviglia e Gentile. Secon…