Ostracodes; witnesses of the Plio-Quaternary boundary in the North Eastern Atlantic preliminary results

Proceedings of the 1" R.C.A.N.S. Congress, Lisboa, October 1992

The use of the boundary element method in the analysis of single lap joints

The most common techniques for stress analysis/strength prediction of adhesive joints involve analytical or numerical methods such as the Finite Element Method (FEM). However, the Boundary Element Method (BEM) is an alternative numerical technique that has been successfully applied for the solution of a wide variety of engineering problems. This work evaluates the applicability of the boundary elem ent code BEASY as a design tool to analyze adhesive joints. The linearity of peak shear and peel stresses with the applied displacement is studied and compared between BEASY and the analytical model of Frostig et al., considering a bonded single-lap joint under tensile loading. The BEM results are also compared with FEM in terms of stress distributions. To evaluate the mesh convergence of BEASY, the influence of the mesh refinement on peak shear and peel stress distributions is assessed. Joint stress predictions are carried out numerically in BEASY and ABAQUS®, and analytically by the models of Volkersen, Goland, and Reissner and Frostig et al. The failure loads for each model are compared with experimental results. The preparation, processing, and mesh creation times are compared for all models. BEASY results presented a good agreement with the conventional methods.

Pliensbachian/Toarcian boundary: the proposed GSSP of Peniche (Portugal)

The Peniche section (Portugal) is considered as a potential stratotype (GSSP) for the Pliensbachian/Toarcian boundary and it is analysed on the background of the available data on the ammonite successions from other Tethyan and NW European areas.

Calcareous nannofossil assemblages around the Pliensbachian/Toarcian boundary in the reference section of Peniche (Portugal)

The Pliensbachian/Toarcian boundary (Lower Jurassic) is well represented in the Lusitanian Basin (Portugal), mainly in the Peniche area, recorded by a marl/limestone series. Calcareous nannofossil assemblages are described herein, with the aim to contribute to the Toarcian GSSP definition. Marly samples were collected 3 m below and 7 m above this boundary and analysed for calcareous nannofossils. The main nannofossils observed were Biscutum finchii, B. grande, Calcivascularis jansae, Crepidolithus crassus, C. granulatus, C. impontus, Lotharingius hauffii, L. sigillatus, L. aff. L. velatus, Schizosphaerella spp. and Tubirhabdus patulus. This assemblage indicates that the Pliensbachian/Toarcian boundary in Peniche lies in the upper part of the NJ5b Subzone. Schizosphaerella and Lotharingius dominate the assemblage. The abundant occurrence of C. jansae and the common occurrence of B. grande indicate a strong Tethyan influence.

Calcareous nannofossil assemblages across the Pliensbachian/Toarcian boundary at the Peniche section (Ponta do Trovão, Lusitanian Basin)

The Peniche section has revealed moderately-to-well preserved calcareous nannofossil assemblages across the Pliensbachian/Toarcian boundary. This good record has allowed the proposition of a refined biostratigraphic scheme. The stage boundary, as defined by ammonites, is comprised within the NJ5b C. impontus (NW Europe; BOWN & COOPER, 1998) or the NJT5b L. sigillatus (Mediterranean Tethys; MATTIOLI & ERBA, 1999) nannofossil subzones. Since in the Lusitanian Basin a mixing of N- and S-Tethyan taxa is observed, both biozonation schemes can be applied. Some nannofossil events (mainly first occurrences) are observed earlier in Portugal than in other Tethyan settings. It is still unclear if these events are real first occurrences. A diversification phase occurred across the Pliensbachian/Toarcian boundary. This phase is well recorded at Peniche, where a change is observed passing from the Pliensbachian, when assemblages are dominated by muroliths, to the Toarcian showing assemblages where placoliths are abundant. A quantification of nannofossils per gram of rock shows that absolute abundances are the highest across the Pliensbachian/Toarcian boundary. Indeed, Peniche exhibits nannofossil abundances very high with respect to correlative levels in other Tethyan settings. The pelagic carbonate fraction (produced by nannofossils) is important in the marly hemi-couplets of Peniche. In some levels, nannofossils account for more than 50% of the total carbonate fraction.

An optimal boundary fair scheduling

Nowadays, many real-time operating systems discretize the time relying on a system time unit. To take this behavior into account, real-time scheduling algorithms must adopt a discrete-time model in which both timing requirements of tasks and their time allocations have to be integer multiples of the system time unit. That is, tasks cannot be executed for less than one time unit, which implies that they always have to achieve a minimum amount of work before they can be preempted. Assuming such a discrete-time model, the authors of Zhu et al. (Proceedings of the 24th IEEE international real-time systems symposium (RTSS 2003), 2003, J Parallel Distrib Comput 71(10):1411–1425, 2011) proposed an efficient “boundary fair” algorithm (named BF) and proved its optimality for the scheduling of periodic tasks while achieving full system utilization. However, BF cannot handle sporadic tasks due to their inherent irregular and unpredictable job release patterns. In this paper, we propose an optimal boundary-fair scheduling algorithm for sporadic tasks (named BF TeX ), which follows the same principle as BF by making scheduling decisions only at the job arrival times and (expected) task deadlines. This new algorithm was implemented in Linux and we show through experiments conducted upon a multicore machine that BF TeX outperforms the state-of-the-art discrete-time optimal scheduler (PD TeX ), benefiting from much less scheduling overheads. Furthermore, it appears from these experimental results that BF TeX is barely dependent on the length of the system time unit while PD TeX —the only other existing solution for the scheduling of sporadic tasks in discrete-time systems—sees its number of preemptions, migrations and the time spent to take scheduling decisions increasing linearly when improving the time resolution of the system.

Characterization of middle-ear condition of Oporto daycare children up-to 3 years-old: A cross sectional study

Objective The aim of this study was to determine tympanometric values of children who attend Oporto daycare centers and further analyze any relations with host and environmental factors. Methods Cross sectional study in a randomly selected sample of 117 daycare children up-to 3-years old from Oporto. Tympanometric measures were collected. Results Children presented in left ear (LE) a mean peak pressure (PP) of −156.53 daPa and a mean compliance of 0.16 cm3. Right ear (RE) revealed a PP of −145.61 daPa and a compliance of 0.19 cm3. Normal tympanograms (type A) had a lower frequency than abnormal tympanograms (type B and type C). There was a positive association between age and compliance (LE: p = 0.016; RE: p = 0.013) and between the presence of rhinorrhea and PP (LE: p = 0.002; RE: p < 0.05). Abnormal tympanograms were more frequent in Spring (RE: p = 0.009), in younger children (LE: p = 0.03) and in children that had rhinorrhea (LE: p = 0.002; RE: p = 0.044). Healthy children had a mean PP of −125.19 daPa and a mean compliance of 0.21 cm3 in LE and a mean PP of −144.27 daPa and a mean compliance of 0.22 cm3 in RE. Conclusion Tympanometric measures presented in this paper may be applicable to Oporto daycare children up-to 3 years-old. Most of daycare children revealed abnormal tympanograms. Age, rhinorrhea and season influenced children's middle-ear condition.

Maintenance of fire sprinkler systems based on the dynamic assessment of its condition

Safety is one of the major concerns of process safety engineers in most industrial facilities all over the world. To this scope, some events play an important role once the effect of their consequences can be assumed as totally undesirable. One of these events refers to the occurrence of a fire. Such event can result in catastrophic consequences for life, equipment, and continuity of activities or even leading to environmental damage. A fire protection equipment with low reliability means that this equipment are often unavailable and thus the risk of a fire increases. Maintenance of fire protection equipment is very important because this kind of systems is mostly in a dormant mode, which gives uncertainty about their operability when demanded in a real situation of fire. This article outlines the importance of tests, inspection, and maintenance operations in the context of a fire sprinkler system and proposes a methodology based on international standards and supported by test/inspection reports to correct the frequency of these actions according to the level of degradation of the components and regarding safety purposes. © 2015 American Institute of Chemical Engineers.

Desenvolvimento de um Controlador de Boundary Scan (Ieee 1149.1)

Mestrado em Engenharia Electrotécnica e de Computadores - Área de Especialização em Automação e Sistemas

Condition-Based Diagnosis of Mechatronic Systems Using a Fractional Calculus Approach

While fractional calculus (FC) is as old as integer calculus, its application has been mainly restricted to mathematics. However, many real systems are better described using FC equations than with integer models. FC is a suitable tool for describing systems characterised by their fractal nature, long-term memory and chaotic behaviour. It is a promising methodology for failure analysis and modelling, since the behaviour of a failing system depends on factors that increase the model’s complexity. This paper explores the proficiency of FC in modelling complex behaviour by tuning only a few parameters. This work proposes a novel two-step strategy for diagnosis, first modelling common failure conditions and, second, by comparing these models with real machine signals and using the difference to feed a computational classifier. Our proposal is validated using an electrical motor coupled with a mechanical gear reducer.

Cohesive law estimation of adhesive joints in mode II condition

The adhesive bonding technique enables both weight and complexity reduction in structures that require some joining technique to be used on account of fabrication/component shape issues. Because of this, adhesive bonding is also one of the main repair methods for metal and composite structures by the strap and scarf configurations. The availability of strength prediction techniques for adhesive joints is essential for their generalized application and it can rely on different approaches, such as mechanics of materials, conventional fracture mechanics or damage mechanics. These two last techniques depend on the measurement of the fracture toughness (GC) of materials. Within the framework of damage mechanics, a valid option is the use of Cohesive Zone Modelling (CZM) coupled with Finite Element (FE) analyses. In this work, CZM laws for adhesive joints considering three adhesives with varying ductility were estimated. The End-Notched Flexure (ENF) test geometry was selected based on overall test simplicity and results accuracy. The adhesives Araldite® AV138, Araldite® 2015 and Sikaforce® 7752 were studied between high-strength aluminium adherends. Estimation of the CZM laws was carried out by an inverse methodology based on a curve fitting procedure, which enabled a precise estimation of the adhesive joints’ behaviour. The work allowed to conclude that a unique set of shear fracture toughness (GIIC) and shear cohesive strength (ts0) exists for each specimen that accurately reproduces the adhesive layer’ behaviour. With this information, the accurate strength prediction of adhesive joints in shear is made possible by CZM.

FATAL OUTCOME OF INFECTION BY DENGUE 4 IN A PATIENT WITH THROMBOCYTOPENIC PURPURA AS A COMORBID CONDITION IN BRAZIL

Dengue is currently a major public-health problem. Dengue virus (DENV) is classified into four distinct serotypes, DENV 1-4. After 28 years of absence, DENV-4 was again detected in Brazil in 2010 in Roraima State, and one year later, the virus was identified in the northern Brazilian states of Amazonas and Pará, followed by Rio de Janeiro and São Paulo. In Minas Gerais, the first confirmed case of DENV-4 occurred in the municipality of Frutal in 2011 and has now been isolated from a growing number of patients. Although DENV-2 is associated with the highest risk of severe forms of the disease and death due to the infection, DENV-4 has also been associated with severe forms of the disease and an increasing risk of hemorrhagic manifestations. Herein, the first fatal case of confirmed DENV-4 in Brazil is reported. The patient was an 11-year-old girl from the municipality of Montes Claros in northern Minas Gerais State, Brazil. She had idiopathic thrombocytopenic purpura as a comorbid condition and presented with a fulminant course of infection, leading to death due to hemorrhagic complications. Diagnosis was confirmed by detection of Dengue-specific antibodies using IgM capture enzyme-linked immunosorbent assay and semi-nested RT-PCR. Primary care physicians and other health-care providers should bear in mind that DENV-4 can also result in severe forms of the disease and lead to hemorrhagic complications and death, mainly when dengue infection is associated with coexisting conditions.

Spatial and temporal analysis of recent drought using vegetation temperature condition index: case of Somali regional state of Ethiopia

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Recent droughts and the impact of North Atlantic Oscillation in Iberia; a spatiotemporal analysis based on vegetation temperature condition Index (VTCI)

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.