Nonlinear dynamical analysis of an aeroelastic system with multi-segmented moment in the pitch degree-of-freedom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of snow data assimilation system with GPS reflectometry snow depth in the Western United States

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Numerical and experimental investigation of a vibration system with non-ideal vibration source

An excitation force that is not influenced by the system's states is said to be an ideal energy source. In real situations, a direct and feedback coupling between the excitation source and the system must always exist. This manifestation of the law of conversation of energy is known as Sommerfeld Effect. In the case of obtaining a mathematical model for such system, additional equations are usually necessary to describe the vibration sources and their coupling with the mechanical system. In this work, a cantilever beam and a non-ideal electric DC motor that is fixed to the beam free end is analyzed. The motor has an unbalanced mass that provides excitation to the system proportional to the current applied to the motor. During the motor's coast up operation, as the excitation frequency gets closer to the beam first natural frequency and if the drive power increases further, the DC motor speed remains constant until it suddenly jumps to a much higher value (simultaneously the vibration amplitude jumps to a much lower value) upon exceeding a critical input power. It was found that the Sommerfeld effect depends on some system parameters and the motor operational procedures. These parameters are explored to avoid the resonance capture in Sommerfeld effect. Numerical simulations and experimental tests are used to help insight this dynamic behavior.

Biogeochemistry of an Amazonian podzol-ferralsol soil system with white kaolin

The podzol-ferralsol soil systems, which cover great areas of Amazonia and other equatorial regions, are frequently associated with kaolin deposits and store and export large amounts of carbon. Although natural organic matter (NOM) plays a key role in their dynamics, little is known about their biogeochemistry. In order to assess the specific role of dissolved organic matter (DOM) on NOM storage in deep horizons and to determine possible relationships between kaolin formation and DOM properties, we studied the groundwater composition of a typical podzol-ferralsol soil catena from the Alto Rio Negro region, Brazil. Groundwater was sampled using tension-free lysimeters placed according to soil morphology. DOC, E-H, p(H), and dissolved Si, Al3+, Fe2+, and Fe3+ were analyzed for all samples and values are given in a database. Quantification of other dissolved ions, small carboxylic acids and SUVA(254) index and acid-base microtitration was achieved on selected samples. Part of the DOM produced by the hydromorphic podzols is directly exported to the blackwater streams; another part percolates at greater depth, and more than 90% of it adsorbs in the Bh-Bhs horizons, allowing carbon storage at depth. Humic substances are preferentially adsorbed with regard to small carboxylic compounds. With regard to kaolin genesis, kaolinite precipitation is favored by Al release from NOM mineralization within the Bh-Bhs and kaolin bleaching is ensured by iron reduction due to acidity and relatively low E-H. Fe2+ mobility can be related to small E-H variations and enhanced by the significant concentration of small carboxylic acids. The long-term result of these processes is the thickening of the kaolin, and it can be inferred that kaolin is likely to occur where active, giant podzols are close to a slope gradient sufficient enough to lower the deep water table.

Glucose Control in Acute Myocardial Infarction: A Pilot Randomized Study Controlled by Continuous Glucose Monitoring System Comparing the Use of Insulin Glargine with Standard of Care

Background: This pilot study aimed to verify if glycemic control can be achieved in type 2 diabetes patients after acute myocardial infarction (AMI), using insulin glargine (iGlar) associated with regular insulin (iReg), compared with the standard intensive care unit protocol, which uses continuous insulin intravenous delivery followed by NPH insulin and iReg (St. Care). Patients and Methods: Patients (n = 20) within 24 h of AMI were randomized to iGlar or St. Care. Therapy was guided exclusively by capillary blood glucose (CBG), but glucometric parameters were also analyzed by blinded continuous glucose monitoring system (CGMS). Results: Mean glycemia was 141 +/- 39 mg/dL for St. Care and 132 +/- 42 mg/dL for iGlar by CBG or 138 +/- 35 mg/dL for St. Care and 129 +/- 34 mg/dL for iGlar by CGMS. Percentage of time in range (80-180 mg/dL) by CGMS was 73 +/- 18% for iGlar and 77 +/- 11% for St. Care. No severe hypoglycemia (<= 40 mg/dL) was detected by CBG, but CGMS indicated 11 (St. Care) and seven (iGlar) excursions in four subjects from each group, mostly in sulfonylurea users (six of eight patients). Conclusions: This pilot study suggests that equivalent glycemic control without increase in severe hyperglycemia may be achieved using iGlar with background iReg. Data outputs were controlled by both CBG and CGMS measurements in a real-life setting to ensure reliability. Based on CGMS measurements, there were significant numbers of glycemic excursions outside of the target range. However, this was not detected by CBG. In addition, the data indicate that previous use of sulfonylurea may be a potential major risk factor for severe hypoglycemia irrespective of the type of insulin treatment.

Bifurcation analysis of an aeroelastic system with concentrated nonlinearities

Analytical and numerical analyses of the nonlinear response of a three-degree-of-freedom nonlinear aeroelastic system are performed. Particularly, the effects of concentrated structural nonlinearities on the different motions are determined. The concentrated nonlinearities are introduced in the pitch, plunge, and flap springs by adding cubic stiffness in each of them. Quasi-steady approximation and the Duhamel formulation are used to model the aerodynamic loads. Using the quasi-steady approach, we derive the normal form of the Hopf bifurcation associated with the system's instability. Using the nonlinear form, three configurations including supercritical and subcritical aeroelastic systems are defined and analyzed numerically. The characteristics of these different configurations in terms of stability and motions are evaluated. The usefulness of the two aerodynamic formulations in the prediction of the different motions beyond the bifurcation is discussed.

Evaluation of multitrophic biofiltration system with new algae species and the sea cucumber "Holothuria sanctori"

Máster Oficial en Cultivos Marinos. Trabajo presentado como requisito parcial para la obtención del Título de Máster Oficial en Cultivos Marinos, otorgado por la Universidad de Las Palmas de Gran Canaria (ULPGC), el Instituto Canario de Ciencias Marinas (ICCM), y el Centro Internacional de Altos Estudios Agronómicos Mediterráneos de Zaragoza (CIHEAM)

Crack measurements in structural concrete with D.I.C. system and validation of a tensile constitutive law

Compared with other mature engineering disciplines, fracture mechanics of concrete is still a developing field and very important for structures like bridges subject to dynamic loading. An historical point of view of what done in the field is provided and then the project is presented. The project presents an application of the Digital Image Correlation (DIC) technique for the detection of cracks at the surface of concrete prisms (500mmx100mmx100mm) subject to flexural loading conditions (Four Point Bending test). The technique provide displacement measurements of the region of interest and from this displacement field information about crack mouth opening (CMOD) are obtained and related to the applied load. The evolution of the fracture process is shown through graphs and graphical maps of the displacement at some step of the loading process. The study shows that it is possible with the DIC system to detect the appearance and evolution of cracks, even before the cracks become visually detectable.

Spastin in the human and mouse central nervous system with special reference to its expression in the hippocampus of mouse pilocarpine model of status epilepticus and temporal lobe epilepsy

In the present in situ hybridization and immunocytochemical studies in the mouse central nervous system (CNS), a strong expression of spastin mRNA and protein was found in Purkinje cells and dentate nucleus in the cerebellum, in hippocampal principal cells and hilar neurons, in amygdala, substantia nigra, striatum, in the motor nuclei of the cranial nerves and in different layers of the cerebral cortex except piriform and entorhinal cortices where only neurons in layer II were strongly stained. Spastin protein and mRNA were weakly expressed in most of the thalamic nuclei. In selected human brain regions such as the cerebral cortex, cerebellum, hippocampus, amygdala, substania nigra and striatum, similar results were obtained. Electron microscopy showed spastin immunopositive staining in the cytoplasma, dendrites, axon terminals and nucleus. In the mouse pilocarpine model of status epilepticus and subsequent temporal lobe epilepsy, spastin expression disappeared in hilar neurons as early as at 2h during pilocarpine induced status epilepticus, and never recovered. At 7 days and 2 months after pilocarpine induced status epilepticus, spastin expression was down-regulated in granule cells in the dentate gyrus, but induced expression was found in reactive astrocytes. The demonstration of widespread distribution of spastin in functionally different brain regions in the present study may provide neuroanatomical basis to explain why different neurological, psychological disorders and cognitive impairment occur in patients with spastin mutation. Down-regulation or loss of spastin expression in hilar neurons may be related to their degeneration and may therefore initiate epileptogenetic events, leading to temporal lobe epilepsy.