Search results for "plastic"

Development of stimulus-sensitive electrospun membranes based on novel biodegradable segmented polyurethane as triggered delivery system for doxorubi…

2022

In this work, redox-sensitive polyurethane urea (PUU) based electrospun membranes have been exploited to chemically tether a pH-sensitive doxorubicin derivative achieved by linking a lipoyl hydrazide to the drug via a hydrazone linkage. First, the lipoyl-hydrazone-doxorubicin derivative labelled as LA-Hy-Doxo has been syn- thesized and characterized. Then, the molecule has been tethered, via a thiol-disulfide exchange reaction, to the redox-sensitive PUU (PolyCEGS) electrospun membrane. The redox-sensitive PolyCEGS PUU has been produced by using PCL-PEG-PCL polyol and glutathione-tetramethyl ester (GSSG-OMe)4 as a chain extender. The LA-Hy- Doxo tethered electrospun membrane has showed a du…

PLASTICS RECOVERY FROM MUNICIPAL WASTE: MAINSTREAMS AND BY-PRODUCTS IN A CASE STUDY IN NORTHERN ITALY.

2014

In the case study dealt with here, the factory treatments of dry Municipal Solid Waste are aimed primarily at materials recovery; restraining energy recovery to the hardly recyclable by-products. The main input consists of the so-called multipak from MSW source-sorted collection; plus packaging waste, paper and cardboard and other similar waste from curb-side collection. The principal fractions produced by the selection plant, own and operated by the Public Company in charge of MSW management, in the Year 2012 were 27 064 tonnes of plastics, 5 066 of paper, 3 014 of tin coated steel and 4 886 tonnes of extraneous fraction to dispose of. A minor – though valuable – product was aluminium. The…

Modellazione FEM del comportamento visco-elastoplastico di conglomerati bituminosi per uso stradale

2010

In questo lavoro si è voluto formulare un modello per descrivere il comportamento meccanico del conglomerato bituminoso di uso stradale che può essere facilmente implementato in programmi software FEM di uso comune, al fine di effettuare una rigorosa analisi strutturale delle pavimentazioni flessibili. Dopo una breve rassegna dei modelli costitutivi esistenti, a partire dai più semplici fino ai più complessi, è possibile concludere che un corretto metodo di modellazione consiste nel dividere la risposta del materiale, in termini di deformazione totale, nelle diverse componenti e di descriverle tutte separatamente. Nel confronto con i risultati sperimentali, il modello proposto è in grado di…

CONGLOMERATI AD ALTO MODULO (EME) MIGLIORATI CON ADDITIVI PLASTICI

2014

Effect of the mineralogical composition on the elastoplastic hydromechanical response of Opalinus Clay shale

2021

Abstract Opalinus Clay is the shale currently under investigation as the host formation for geological radioactive waste disposal in Switzerland. Its hydromechanical response has been widely studied, and the experimental results show a range of values whose dispersion needs to be clarified. This work aims to explain the dispersion in the literature results by correlating the hydro-mechanical response to the mineralogical variability of the tested specimens . Based on published microstructural studies, the Opalinus Clay shale is herein schematised as a sequence of two kinds of layers: the shaly (high in clay-mineral content) and the sandy (low in clay-mineral content) layers. The mineralogic…

Optimal design of structures under dynamic loading

2009

P-Delta effect in structural optimization

2010

The present paper is devoted to the optimal design of structures constituted by elastic perfectly plastic material. In particular, reference will be made to the minimum volume design of multi-storey steel frames taking into account the P-Delta effect. For the sake of generality, the structure is thought as discretized into compatible finite elements and subjected to fixed and quasi-statically acting (wind) loads as well as to dynamic (seismic) loads. The effects of the dynamic actions are studied by utilizing a classical modal technique. The relevant optimal design problem is formulated on the grounds of a statical approach and different resistance limits are considered: in particular, it i…

Flexural behavior of R.C. columns externally wrapped with FRP sheets

2012

In the present paper the compressive and flexural behavior of R.C. columns externally wrapped with FRP layers is examined. The investigation refers to a short compressed R.C. member having circular transverse cross-section and reinforced with longitudinal bars and transverse hoops or spirals. A first phase of the investigation was addressed to describing the constitutive laws of constituent materials (confined concrete core, steel bars in compression and in tension, FRP in tension). The second phase of the research was addressed to deriving the compressive and flexural responses in terms of load-axial shortening curves and momentaxial force interaction domain, to be compared with experiment…

Finite element modeling of the shear behavior of hybrid steel trussed concrete beams

2015

The development and calibration of a three-dimensional (3D) nonlinear Finite Element (FE) model is presented with the aim of investigating the shear behavior of steel-concrete composite beams realized with a steel truss embedded into a concrete core and named Hybrid Steel Trussed-Concrete Beams (HSTCBs). The model is calibrated on the results of a reference experimental campaign of three-point bending tests on HSTCBs realized at the Laboratory of Structures of the University of Palermo. The actual behavior at the steel-concrete interface has been introduced in the model through the implementa-tion of a cohesive constitutive relationship. Furthermore, the damaged plasticity of concrete has b…

FE modeling of Partially Steel-Jacketed (PSJ) RC columns using CDP model

2018

This paper deepens the finite element modeling (FEM) method to reproduce the compressive behavior of partially steel-jacketed (PSJ) RC columns by means of the Concrete Damaged Plasticity (CDP) Model available in ABAQUS software. Although the efficiency of the CDP model is widely proven for reinforced concrete columns at low confining pressure, when the confinement level becomes high the standard plasticity parameters may not be suitable to obtain reliable results. This paper deals with these limitations and presents an analytically based strategy to fix the parameters of the Concrete Damaged Plasticity (CDP) model. Focusing on a realistic prediction of load-bearing capacity of PSJ RC column…