Search results for "COMPOSITE"

An investigation of the mechanical properties of rubber modified asphalt mixtures using a modified dry process

2017

Incorporating recycling tyres into asphalt mixtures contributes to solving a serious environmental problem as well as the potential of improving the mechanical performance of asphalt mixtures. The recycled tyre rubber is added by two technologies known as the dry process (when rubber particles are treated as an aggregate modifier) and the wet process (when rubber particles are treated as a binder modifier). Although, the dry process is easier and requires minimal or no modification in the asphalt plant, the inconsistency in field performance makes the dry process not widely used. The main reason for this is believed to be the lack of interaction between the rubber particles and binder. In o…

Green geopolymeric concrete using grits for applications in construction

2018

Abstract This work investigates the production a green geopolymer-based concrete for a sustainable construction material using biomass wastes from a kraft pulp industry: fly ash (as main alumina-silicate source) and grits (as aggregate). Moreover, a simple, reproducible, ambient temperature, and low-cost manufacture is followed. Mix design aims to maximize wastes incorporation and optimize the mechanical performance. Preliminary tests indicate that the used wastes may be successfully employed to produce green geopolymeric concretes with satisfying mechanical performance (up to 18 MPa), according to the European standards. Furthermore, they represent a viable solution to reduce the environme…

Formation of supramolecular aggregates by hydrogen bonding based on bispyrimidine and bisbarbituric acid

1997

Hydrogen bonds between bispyrimidine and bisbarbituric acid in equal molar ratio can lead to the formation of supramolecular aggregates. This is established by TEM, IR and DSC measurements. Additionally, WAXS pattern showed that the aggregate is of laminar structure. Both the hydrolysis of this system and termination of the aggregate's growth were studied.

SW—Soil and Water

2002

Abstract Recent research has directed attention to the size distribution of eroded material because of its influence on deposition mechanics and in carrying capacity of pollutant materials. At first, in this paper the relationship between aggregate breakdown mechanism and erosion processes is briefly reviewed. Then the link between the clay enrichment ratio and the sediment delivery ratio at morphological unit scale is investigated. For 129 soil samples well distributed over the Sicilian Sparacia basin, the values for the experimental clay enrichment ratio calculated by the measured ultimate grain-size distributions are compared with the theoretical clay enrichment ratio values obtained by …

Dynamic Mechanical Behavior Analysis of Flax/Jute Fiber-Reinforced Composites under Salt-Fog Spray Environment

2020

Over the last decades, natural fiber-reinforced polymer composites (NFRPs) gained great attention in several engineering fields thanks to the reduction of the environmental impact and the end-of-life cost disposal. Unfortunately, the use of NFRPs is limited, mainly due to their weak resistance against humid environments. Since limited literature is available about the evolution of the dynamic mechanical response of NFRPs under aggressive environments, this paper aims to investigate the damping properties of flax, jute and flax/jute epoxy composites exposed to salt-fog up to 60 days. Furthermore, sodium bicarbonate fiber treatment was performed to improve the composites&rsquo

2016

In studying holistic face processing across the life-span there are only few attempts to separate face-specific from general aging effects. Here we used the complete design of the composite paradigm (Cheung et al., 2008) with faces and novel non-face control objects (watches) to investigate composite effects in young (18-32 years) and older adults (63-78 years). We included cueing conditions to alert using a narrow or a wide attentional focus when comparing the composite objects, and used brief and relaxed exposure durations for stimulus presentation. Young adults showed large composite effects for faces, but none for watches. In contrast, older adults showed strong composite effects for fa…

The influence of the nature of the surface oxide on the adhesive fracture energy of aluminium-bonded joints as measured by T-peel tests

2008

Abstract Modification of aluminium alloy substrates microstructure and morphology by depositing new oxide layers on top of the metal surface has been investigated, with the aim of improving adhesion. The effect of treating the metal with boiling water or immersing it in a cerate bath has been studied by means of electron microscopy, contact angle measurements and peeling tests. The formation of pseudoboehmite layers or cerium conversion coatings both led to an increase in joint's adhesive fracture energy and more durable adhesive bonds with respect to joints obtained with “mechanically grinded only” substrates. Differences in the performance of the bonded joints has been discussed in terms …

RGD-mimic polyamidoamine-montmorillonite composites with tunable stiffness as scaffolds for bone tissue-engineering applications

2017

This paper reports on the development of montmorillonite (MMT)-reinforced hydrogels, based on a peptidomimetic polyamidoamine carrying guanidine pendants (AGMA1), as substrates for the osteo-induction of osteoblast precursor cells. AGMA1 hydrogels of various degrees of crosslinking responded favourably to MMT reinforcement, giving rise to composite hydrogels with shear storage modulus G', when fully swollen in water, up to 200 kPa, i.e. 20 times higher than the virgin hydrogels and of the same order or higher than other hydrogel-based composites proposed for orthopaedic applications. This significant improvement was ascribed to the effective interpenetration between the polymer matrix and t…

Reconstructing Bronze Age diets and farming strategies at the early Bronze Age sites of La Bastida and Gatas (southeast Iberia) using stable isotope …

2020

The El Argar society of the Bronze Age in the southeast of the Iberian Peninsula (2200–1550 cal BCE) was among the first complex societies in Europe. Its economy was based on cereal cultivation and metallurgy, it was organized hierarchically, and successively expanded its territory. Most of the monumentally fortified settlements lay on steeply sloped mountains, separated by fertile plains, and allowed optimal control of the area. Here, we explore El Argar human diets, animal husbandry strategies, and food webs using stable carbon and nitrogen isotope analysis of charred cereal grains as well as human and animal bone collagen. The sample comprised 75 human individuals from the sites of La Ba…

DEVELOPMENT AND APPLICATIONS OF A VIRTUAL HYBRID PLATFORM FOR MULTISCALE ANALYSIS OF ADVANCED STRUCTURES OF AIRCRAFT (DEVISU)

2022

This paper outlines the main findings of the project “DEvelopment and applications of a VIrtual hybrid platform for multiscale analysis of advanced StructUres of aircraft” (DEVISU), which deals with failure of composite structures and noise/vibration reduction, along with investigation of new materials for aerospace applications.