Live algae as a vector candidate for hydrophobic polychlorinated biphenyls translocation to bivalve filter feeders for laboratory toxicity test Author Details

Abstract Live algae carrying hydrophobic xenobiotics can be an effective vector candidate for the chemical translocation to filter feeders in the laboratory toxicity test, but information on their application is lacking. Time-course uptake and elimination of polychlorinated biphenyls (PCBs) (0, 50, 100, and 500 ng g -1 ) by two key algal foods, Isochrysis galbana and Tetraselmis suecica, were measured. Both of the algae achieved maximum concentration in an hour after PCBs exposure regardless the chemical concentrations in our time-course measurements (0, 1, 5, 10, 24, 48 and 72 hrs). Once achieved the maximum concentration, the algae shortly exhibited elimination or eliminating tendency depending on the chemical concentrations. Algae exposed to the chemical for 1 and 24 hrs (hereafter 1 and 24 hr vectors, respectively) were then evaluated as a chemical translocation vector by feeding test to larval and spat Crassostrea gigas. In the feeding test the 24 hr vector, which contained lower chemicals than the 1-hr vector, appeared to be more damaging the early lives of the oyster. This was particularly significant for vectors of higher PCBs (p<0.05), probably due to algal reduction in food value by the prolonged chemical stress. These findings imply that 1 hr exposure is long enough for a generation of algal vector for laboratory toxicity test, minimizing data error resulted from reduction in food value by longer chemical stress

4-Hydroxy­phenyl 4-fluoro­benzoate

In the title compound, C13H9FO3, the dihedral angle between the two benzene rings is 59.86 (4)°. In the crystal, inter­molecular O—H⋯H hydrogen bonds lead to molecular chains propagating in [010]

Compressive performance of 50 MPa strength concrete-filled square and circular tube (CFT) columns using recycled aggregate

[EN] Recycled aggregate is an environmentally self-sustainable solution that can reduce construction waste and replace natural aggregates. However, there is a disadvantage in concrete such as initial strength drop and long-term strength development. Therefore, the interaction effect of the two materials can be expected by filling the cyclic aggregate concrete in the CFT column. In order to develop a concrete with compressive strength of 50 MPa as a recycled aggregate, we carried out a mixing experiment and fabricated 18 specimens to confirm the compressive behavior of a RCFT (Recycled Concrete Filled Tube) column that can be applied to actual buildings. Variable is the shape and thickness of steel pipe, concrete strength and mixing ratio, and coarse aggregate and fine aggregate are all used as recycled aggregate. The optimum mixing ratio for recycled aggregate concrete to be filled in the CFT filled steel pipe was found through three concrete preliminary mixing experiments. In addition, the compression test of the RCFT column was carried out to observe and analyze the buckling shape of the CFT column. Based on the analysis of the buckling configuration and the experimental data, the load-displacement curves of the specimens were drawn and the compressive behavior was analyzed.Choi, S.; Choi, WH.; Lee, K.; Ryoo, J.; Kim, S.; Park, Y. (2018). Compressive performance of 50 MPa strength concrete-filled square and circular tube (CFT) columns using recycled aggregate. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 305-313. https://doi.org/10.4995/ASCCS2018.2018.7021OCS30531

VLSH: Voronoi-based Locality Sensitive Hashing

Abstract-We present a fast, yet accurate k-nearest neighbor search algorithm for high-dimensional sampling-based motion planners. Our technique is built on top of Locality Sensitive Hashing (LSH), but is extended to support arbitrary distance metrics used for motion planning problems and adapt irregular distributions of samples generated in the configuration space. To enable such novel characteristics our method embeds samples generated in the configuration space into a simple l2 norm space by using pivot points. We then implicitly define Voronoi regions and use local LSHs with varying quantization factors for those Voronoi regions. We have applied our method and other prior techniques to high-dimensional motion planning problems. Our method is able to show performance improvement by a factor of up to three times even with higher accuracy over prior, approximate nearest neighbor search techniques