Inspection and diagnosis tests for structural safety evaluation: A case study

Diagnosis and assessment of existing structures is a developing area due to the appearance of a high number of building defects, structural and non-structural deterioration and precocious loss of quality, and, consequently, lower expected durability. With the aim of verifying the viability of rehabilitation or the need to demolish an existing fifteen year old parking building, several inspections and diagnostic non-destructive and destructive testing, visual inspection, were carried out to evaluate the structural safety conditions

A Direct Multigrid Poisson Solver for Oct-Tree Adaptive Meshes

We describe a finite-volume method for solving the Poisson equation on oct-tree adaptive meshes using direct solvers for individual mesh blocks. The method is a modified version of the method presented by Huang and Greengard (2000), which works with finite-difference meshes and does not allow for shared boundaries between refined patches. Our algorithm is implemented within the FLASH code framework and makes use of the PARAMESH library, permitting efficient use of parallel computers. We describe the algorithm and present test results that demonstrate its accuracy.Comment: 10 pages, 6 figures, accepted by the Astrophysical Journal; minor revisions in response to referee's comments; added char

X-ray image separation via coupled dictionary learning

In support of art investigation, we propose a new source sepa- ration method that unmixes a single X-ray scan acquired from double-sided paintings. Unlike prior source separation meth- ods, which are based on statistical or structural incoherence of the sources, we use visual images taken from the front- and back-side of the panel to drive the separation process. The coupling of the two imaging modalities is achieved via a new multi-scale dictionary learning method. Experimental results demonstrate that our method succeeds in the discrimination of the sources, while state-of-the-art methods fail to do so.Comment: To be presented at the IEEE International Conference on Image Processing (ICIP), 201

Multi-modal dictionary learning for image separation with application in art investigation

In support of art investigation, we propose a new source separation method that unmixes a single X-ray scan acquired from double-sided paintings. In this problem, the X-ray signals to be separated have similar morphological characteristics, which brings previous source separation methods to their limits. Our solution is to use photographs taken from the front and back-side of the panel to drive the separation process. The crux of our approach relies on the coupling of the two imaging modalities (photographs and X-rays) using a novel coupled dictionary learning framework able to capture both common and disparate features across the modalities using parsimonious representations; the common component models features shared by the multi-modal images, whereas the innovation component captures modality-specific information. As such, our model enables the formulation of appropriately regularized convex optimization procedures that lead to the accurate separation of the X-rays. Our dictionary learning framework can be tailored both to a single- and a multi-scale framework, with the latter leading to a significant performance improvement. Moreover, to improve further on the visual quality of the separated images, we propose to train coupled dictionaries that ignore certain parts of the painting corresponding to craquelure. Experimentation on synthetic and real data - taken from digital acquisition of the Ghent Altarpiece (1432) - confirms the superiority of our method against the state-of-the-art morphological component analysis technique that uses either fixed or trained dictionaries to perform image separation.Comment: submitted to IEEE Transactions on Images Processin

REDUCED-SCALE STUDY OF LIQUID FUEL STORAGE TANK FIRE USING FIRE DYNAMICS SIMULATOR

Most of the accidents that occur in liquid fuel storage tank parks are caused by fire. This paper presents a numerical study using Large Eddy Simulation through Fire Dynamics Simulator (FDS) for the simulation of liquid fuel (ethanol) storage tanks at different scales (real-scale 1:1, and reduced- scales, 1:2, 1:4, 1:8). This paper proposes correlations for flame height, and temperature profile and radiative heat flux profile in the region adjacent to the tanks. Correlations have as inputs the diameters of the tanks in real- and reduced-scale, temperature profiles and radiative heat flux profiles for a reduced-scale tank simulation, and then provide as outputs flame height and temperature profiles and radiative heat flux profiles for the tank in real- scale. Percentage errors of the correlations found in this study are lower than 2.0% and 0.6% for the maximum radiative heat flux and maximum temperature, respectively

Chemosymbiotic species from the Gulf of Cadiz

Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin) revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses ( 13C, 15N and 34S) and investigate the intra-specific variation of isotope signatures within and between study sites. During our studies, we identified twenty siboglinidae and nine bivalve chemosymbiotic species living in fifteen mud volcanoes. Solemyid bivalves and tubeworms of the genus Siboglinum are widespread in the study area, whereas other species were found in a single mud volcano (e.g. “Bathymodiolus” mauritanicus) or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata). Species distribution suggests that different species may adjust their position within the sediment according to their particular needs, and to the intensity and variability of the chemical substrata supply. Tissue stable isotope signatures for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values) and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge on distributional patterns and resource partitioning of chemosymbiotic species and highlights how trophic fuelling varies on spatial scales with direct implications to seep assemblages and potentially to the biodiversity of continental margin

Produção de pólen por abelhas melíferas (Apis mellifera) em área de cultivo de manga (Mangifera indica L.) no projeto irrigado de Maniçoba, Juazeiro-BA.

Para incrementar a produção da manga em áreas irrigadas no Vale do Submédio São Francisco, os produtores utilizam colmeias de abelhas Apis mellifera, que realizam sua polinização. Entretanto, não se sabe se paralelamente os apicultores poderiam aproveitar as abelhas nas áreas de cultivo também para a produção de pólen apícola. Desta forma, este trabalho foi realizado com o objetivo de avaliar a produção de pólen por colmeias de A. mellifera em área de cultivo de manga no projeto irrigado de Maniçoba, Juazeiro-BA. O pólen foi coletado por meio de coletor de pólen frontal em duas colmeias previamente padronizadas quanto à quantidade de áreas de cria e alimento estocado. As coletas foram realizadas a cada 24 horas, por cinco dias consecutivos, em outubro de 2011. Os grãos de pólen retirados dos coletores foram armazenados em embalagens plásticas individuais, secados em estufa a 40-50ºC, durante 24 horas e, em seguida, pesados em balança de precisão. A coleta de pólen foi baixa em ambas as colônias durante todo o período experimental. No entanto, em cada dia, a colônia 1 coletou relativamente mais pólen que a colônia 2, embora estas diferenças não foram significativas. Seria necessário repetir o experimento em maior número de áreas de cultivo para confirmar que a produção é realmente muito baixa, e assim, não indicar esta atividade como alternativa para os apicultores da região