A Feasibility Study of BBP for predicting shear capacity of FRP reinforced concrete beams without stirrups.

yesShear failure of concrete elements reinforced with Fiber Reinforced Polymer (FRP) bars is generally brittle, requiring accurate predictions to avoid it. In the last decade, a variety of artificial intelligence based approaches have been successfully applied to predict the shear capacity of FRP Reinforced Concrete (FRP-RC). In this paper, a new approach, namely, biogeography-based programming (BBP) is introduced for predicting the shear capacity of FRP-RC beams based on test results available in the literature. The performance of the BBP model is compared with several shear design equations, two previously developed artificial intelligence models and experimental results. It was found that the proposed model provides the most accurate results in calculating the shear capacity of FRP-RC beams among the considered shear capacity models. The proposed BBP model can also correctly predict the trend of different influencing variables on the shear capacity of FRP-RC beams

Design of wind farm layout with non-uniform turbines using fitness difference based BBO

Biogeography-based optimization (BBO) is an emerging meta-heuristic algorithm. BBO is inspired from the migration of species from one island to another. This study presents the solution of the wind farm layout optimization problem with wind turbines having non-uniform hub heights and rotor radii using BBO and an improved version of BBO. This study proposes an improved version of BBO, Fitness Difference Based BBO (FD-BBO). FD-BBO is obtained by incorporating the concept of fitness differences in original BBO. First, in order to justify the superiority of FD-BBO over BBO, it is tested over $15$ standard test problems of optimization. The numerical results of FD-BBO are compared with the original version of BBO and an advanced version of BBO, Blended BBO (BBBO). Through graphical and statistical analyses, FD-BBO is established to be an efficient and accurate algorithm. The BBO, BBBO and FD-BBO are than applied to solve the wind farm layout optimization problem. In the considered problem, not only the location of the wind turbines but hub heights and rotor radii are also taken as decision variables. Two cases of the problems are dealt: $26$ turbines in the farm size of $2000m$ $\times$ $2000m$ and $30$ turbines in the farm size of $2000m$ $\times$ $2000m$. Numerical results are compared with earlier published results and that of original BBO and Blended BBO. It is found that FD-BBO is the better approach to solving the problem under consideration

Molecular Techniques Reveal Wide Phyletic Diversity of Heterotrophic Microbes Associated with Discodermia spp. (Porifera: Demospongiae)

Sponges are well known to harbor large numbers of heterotrophic microbes within their mesohyl. Studies to determine the diversity of these associated microbes have been attempted for only a few shallow water species. We cultured various microorganisms from several species of Discodermia collected from deep water using the \u27Johnson-Sea-Link\u27 manned submersibles, and characterised them by standard microbiological identification methods. Characterisation of a small proportion (ca. 10%) of the total and potential eubacterial isolate collection with molecular systematics techniques revealed a wide diversity of microbes. Phylogenetic analyses of 32 small subunit (SSU) 16S-like rRNA gene sequences from different micorbes indicated high levels of taxonomic diversity assoiated with this genus of sponge. For example, bacteria from at least five cubacterial subdivisions - gamma, alpha, beta, Cytophaga and Gram positive - were isolated from the mesohyl of Discodermia. Several strains were unidentifiable from current sequence databases. No overlap was found between sequences of 24 isolates and 8 sequences obtained by PCR and cloning directly from sponge samples. The abundance and diversity of microbes associated with sponges such as Discodermia suggest that they may play important roles in marine microbial ecology, dispersal and evolution

Lack of Chemical Defense in Two Species of Stalked Crinoids: Support for the Predation Hypothesis for Mesozoic Bathymetric Restriction

Methanol/dichloromethane extracts of (1) the arms and pinnules, and (2) the stalk and cirri of the deep water stalked crinoids Endoxocrinus parrae (Gervais) and Neocrinus decorus (Carpenter) were imbedded at ecologically relevant volumetric concentrations in alginate food pellets containing 2% krill as a feeding stimulant and presented in situ to an assemblage of shallow-water reef fish. Experimental pellets were highly palatable to reef fish; no significant differences in pellet consumption occurred between experimental pellets containing extracts from either species of stalked crinoid or control pellets. Small pieces of cirri, stalks, calyx, arms and pinnules of both species were also tested in in situ feeding assays. While immediate consumption by fish was not apparent, Blue Headed Wrasse (Thalassoma bifasciatum (Block)) and Dusky Damselfish (Stegastes fuscus (Cuvier)) bit at pieces of each body component. Similar fish biting behaviors were also observed when two living Endoxocrinus parrae were deployed on the shallow reef. Observations indicate that neither species of stalked crinoid is chemically defended from predation by a natural assemblage of reef fish. This supports the predation hypothesis that restriction of stalked crinoids in deep-water habitats may have resulted from the Mesozoic radiation of durophagous fishes in shallow seas, resulting in a reduction of stalked crinoids from shallow water