Search results for "BASAL"
showing 10 items of 920 documents
Outcomes of intraguild interactions between two egg parasitoids in field and semi-field conditions
2012
Intraguild interactions between two egg parasitoids, Trissolcus basalis (Wollaston) and Ooencyrtus telenomicida (Vassiliev) exploring egg masses of the Southern Green Stink Bug Nezara viridula (L.) were investigated in field and semi-field conditions. Field trials were conducted in tomato fields by using sentinel and naturally laid egg masses in 2010 and 2011. Egg parasitoids monitoring, by sentinel egg masses placed weekly on plants during the tomato growing season and recollected one week later, showed that T. basalis occurs from June to October, whereas O. telenomicida occurs mainly in July and August. In the same fields, collections of naturally laid egg masses display different types o…
Endogenous and exogenous factors affecting host chemical footprint exploitation by a hymenopterous egg parasitoid
2014
During the host location process, parasitoids encounter and explore a great variety of volatile and contact semiochemicals from the host-plant complex. In the system Nezara viridula and its egg parasitoid Trissolcus basalis, when wasps land on a plant, they can taste chemical footprints left by walking adult hosts. These cues represent a set of indirect host-related contact kairomones that induce arrestment and motivated searching behavior, as they drive wasps in an area where there is a high probability of finding hosts but are not able to “promise” the presence of the suitable host stage. Patch time allocation is strongly modified by experience gained during foraging on host traces. In fa…
Effect of dual biotic stress on plant volatile synomones used by egg parasitoids
2014
Studies on semiochemical communication have demonstrated that broad bean plant, Vicia faba, emits volatile synomones induced by feeding and oviposition activities of the southern green stink bug, Nezara viridula, which recruit the egg parasitoid Trissolcus basalis. However plants growing in agro-ecosystems can be attacked by several herbivore species that could affect both above and belowground plant tissues with possible consequences for parasitoid recruitment. For example, broad bean plants can also be attacked by the leaf weevil, Sitona lineatus, and simultaneous attacks by the southern green stink bug and the leaf weevil can occur in agro- ecosystems. The purpose of this work was to inv…
Petrologic constraints on melting conditions in the Strait of Sicily Rift Zone.
2013
The Strait of Sicily Rift Zone (SSRZ) is a northwest-southeast trending transtensional rift situated in the Mediterranean Sea between Sicily and north Africa. The SSRZ consists of three basins: the Pantelleria Trough, the Linosa Basin, and the Malta Trough. Volcanoes are situated in or adjacent to all except the Malta Trough, and include two islands (Pantelleria and Linosa) and several seamounts. The thickness of the crust throughout the region is 25-35 km, but thins to 16-18 km in the basins of the SSRZ. The Pantelleria Trough is characterized by high average heat flow values and a strong positive Bourger anomaly, which suggest assthenospheric upwelling to ~60 km and the presence of abunda…
Mechanical and environmental performance comparisons of improved asphalt pavement wearing courses with high quality aggregates, steel slags, and poly…
2023
The use of waste materials in the construction of hot mix asphalt (HMA) pavements is an important opportunity for environmental sustainability. When properly designed, the alternative mixtures may also guarantee excellent mechanical performance. In this study, the results of an experimental analysis carried out on dense-graded HMAs are presented. In particular, the performance of a "traditional" surface mixture with limestone aggregate (designed with neat bitumen or a polymer-modified bitumen within the typical acceptance requirements for intended use in wearing courses) was compared with two alternative mixtures. The research investigated a surface mixture including coarse basaltic aggrega…
EXPERIMENTAL ANALYSIS OF SMALL CLAY BRICK CYLINDERS CONFINED BY BFRP GRID UNDER AXIAL COMPRESSION
2019
Many investigations have shown that fibre reinforced polymer (FRP) composites can be effectively used to induce a passive confinement action on masonry columns and improve their axial capacity and ductility. This paper presents the results of an experimental study on the compressive behaviour of clay brick masonry cylinders externally wrapped with basalt fiber reinforced polymer (BFRP) grids. The circular section shape was chosen to assess the pure confinement effect on the masonry material. Fourteen clay brick masonry cylinders, cored from two different masonry assembly types, were confined with one or two layers of BFRP grids. The two assemblies were used to investigate the effect of vert…
On the use of digital image correlation (DIC) for evaluating the tensile behaviour of BFRCM strips
2019
Fibre Reinforced Cementitious Matrix (FRCM) composites are becoming largely adopted for retrofitting masonry structures. These materials offer several advantages in comparison to Fibre Reinforced Polymer (FRP) composites, such as good resistance to fire and high temperatures, vapour permeability, possibility to be applied on wet surfaces, higher compatibility with the masonry substrate. However, the tensile behavior of FRCM materials is more complex compared to FRP composites, due to the limited tensile strength of the cement-based matrix. For this reason, FRCM materials require appropriate tensile characterization and, in this context, the use of non-conventional measurement systems, such …
Performance Assessment of Basalt FRCM for the Confinement of Clay Brick Masonry Cylinders
2021
Fibre Reinforced Cementitious Matrix (FRCM) composites have been proved to be a suitable strengthening material for masonry structures in the last years. Moreover, basalt fibres are increasingly used as reinforcement of composites as a more sustainable alternative to glass fibres. The goal of this work is to investigate the effectiveness of basalt FRCM to confine masonry circular columns. A total of eighteen clay brick masonry cylinders were tested in compression. The specimens were cored from two different masonry assemblies and wrapped with one or two layers of BFRCM composite. The stress-strain curves and the gains of strength and strain capacity of confined cylinders compared to the con…
BFRP grid confined clay brick masonry cylinders under axial compression: Experimental results
2018
The use of composite materials for retrofitting of masonry structures has received great attention during the last two decades. For masonry buildings there are several advantages in using composite materials. Traditional techniques that were largely used and investigated in the past, may be inadequate in seismic areas where the added mass could increase seismic actions. Moreover, for historical and architectural heritage structures, the compatibility, sustainability and reversibility of the intervention is a key factor for the selection of the most appropriate strengthening system. Many investigations have shown that fibre reinforced polymers (FRP) can be effectively used to induce a passiv…
Experimental investigation on basalt grid cementitious mortar strips in tension
2018
Fibre reinforced cementitious matrix (FRCM) composite materials are currently receiving great attention for strengthening reinforced concrete and masonry structures, especially when specific preservation criteria need to be fulfilled. FRCM composites can be a convenient alternative to fibre-reinforced polymers (FRP) for their better resistance to high temperature and compatibility with stone and masonry structures. In this work an experimental study for the tensile characterization of basalt reinforced cementitious matrix (BRCM) strips is presented. Strips with one, two or three layers of grid were tested in tension to study the effect of reinforcement ratio on the tensile stress-strain res…