Reproduction and feeding biology of madagascar meager (Argyrosomus hololepidotus) from Khuzestan coastal waters

Biological attributes of Madagascar Meager (Argyrosomus hololepidotus) was studied from October 2008 to September 2009 in coastal waters of Khuzestan province. Average maximum length was 128.4±7.50 in October and average minimum length was 104.86±12.47 in May. The maximum weight was 27500g, the minimum weight was 5700g and mean weight for males and females were 15.222±4.40 and 16.942±5.09, respectively. Reproductive studies showed that peak maturity season occurred in July. The length­ weight relationship were calculated as W=0.042L 2 70 for males and W=0.06L2 61for females. The male-female sex ratio was calculated as 1:1.07 and chi-square analysis showed no significant difference (P>0.05) between the two sexes. The average absolute and relative fecundity were estimated to be 4054045±37265 and 179.19±50.41, respectively Madagascar Meager is carnivore and we found the diet of the species consisted of fish (75%), crustaceans (20%) and mollusks (5%). Analysis of monthly variation in the condition factor (CF) indicated a fluctuation throughout the year, with a high level during May. Vacuity index indicated a higher feeding rate in males compared to females. We also found that the species continues feeding in the spawning season

A meso-scale discrete element method framework to simulate thermo-mechanical failure of concrete subjected to elevated temperatures

Preprint versionThis paper presents mesoscale thermo-mechanical analyses of plain (unreinforced) concrete based on the discrete element method (DEM). The proposed discontinuum modelling strategy represents the aggregates and matrix as a system of deformable polyhedral blocks, interacting along their boundaries. The nodal velocities of each block are calculated via the explicit integration scheme of DEM, and contact stresses are computed based on the relative contact displacements of the adjacent blocks. To better predict the thermo-mechanical behaviour of concrete, fracture energy-based contact constitutive models are implemented by considering temperature dependency at the zone and contact properties. First, the discrete meso models are tested under uniaxial compression loading at room temperature. Then, transient thermo-mechanical tests are performed considering different load levels. The results of the computational models are compared with the macroscopic response quantities of concrete obtained from the available experimental studies in the literature. The results indicate that the developed DEM framework predicts the complex mesoscale thermo-mechanical response history and the typical damage progression observed in concrete. Furthermore, the fracture patterns, crack propagation with temperature, and the differential thermal expansion phenomena are studied in detail.The first author would like to acknowledge the post-doctoral fellowship offered by the University of Minho for this research. This work was partly supported by UID/ECI/04029/2019 - ISISE, funded by national funds through the FCT/MCTES (PIDDAC)