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Ensaios não destrutivos aplicados à madeira serrada e estruturas : técnicas potenciais para uso no Brasil
(Universidade Federal de São Carlos, 2011-11-18) Cardin, Viviane de Salles; Sales, Almir; https://lattes.cnpq.br/7377787166073311; https://lattes.cnpq.br/0017473566444722
The wood has many different characteristics, resulting, in part, of the conditions in which the tree grows. The physical conditions of the wood are also influenced by its complex internal structure, resulting in an anisotropic behavior. Within this variability, its best use and application can be reached through non-destructive methods. The non-destructive methodology is performed to verify the existence or inexistence of discontinuities or defects, without changing its later use. This work aims at presenting the non-destructive techniques in wood with potential use in Brazil. It also aims at applying the ultrasound technique in lumber pieces of Pinus sp of structural dimensions, with the purpose of verifying the accuracy of such technique, comparing it to the values obtained in destructive tests (static bending tests). The coefficient of determination (R2) obtained from the regression line between the static modulus of elasticity and dynamic modulus of elasticity with the use of ultrasound was 0.66, that allows affirming that this technique has accuracy in the assessment of mechanical pieces of wood.
Eliminação de parâmetros perturbadores em um modelo de captura-recaptura
(Universidade Federal de São Carlos, 2011-11-18) Salasar, Luis Ernesto Bueno; Leite, José Galvão; https://lattes.cnpq.br/0677440386988572; https://lattes.cnpq.br/5464564215528609
The capture-recapture process, largely used in the estimation of the number of elements of animal population, is also applied to other branches of knowledge like Epidemiology, Linguistics, Software reliability, Ecology, among others. One of the _rst applications of this method was done by Laplace in 1783, with aim at estimate the number of inhabitants of France. Later, Carl G. J. Petersen in 1889 and Lincoln in 1930 applied the same estimator in the context of animal populations. This estimator has being known in literature as _Lincoln-Petersen_ estimator. In the mid-twentieth century several researchers dedicated themselves to the formulation of statistical models appropriated for the estimation of population size, which caused a substantial increase in the amount of theoretical and applied works on the subject. The capture-recapture models are constructed under certain assumptions relating to the population, the sampling procedure and the experimental conditions. The main assumption that distinguishes models concerns the change in the number of individuals in the population during the period of the experiment. Models that allow for births, deaths or migration are called open population models, while models that does not allow for these events to occur are called closed population models. In this work, the goal is to characterize likelihood functions obtained by applying methods of elimination of nuissance parameters in the case of closed population models. Based on these likelihood functions, we discuss methods for point and interval estimation of the population size. The estimation methods are illustrated on a real data-set and their frequentist properties are analised via Monte Carlo simulation.
Toxicidade da deltametrina (formulação Butox® CE25) nas respostas cardio-respiratórias da tilápia-do-Nilo (Oreochromis niloticus)
(Universidade Federal de São Carlos, 2011-11-18) Silva, Aline Callegari; Rantin, Francisco Tadeu; https://lattes.cnpq.br/3546242299713690
Deltamethrin is a synthetic pyrethroid pesticide, type II, considered of low persistence in the environment and widely utilized in agriculture and aquaculture to control plagues and aquatic parasites respectivamently. In spite of it low toxicity in mammals, this pesticide can be extremely toxic for fish. In this study, we evaluate the effects of a sub-lethal concentration (7.3 μg L-1, 50% of LC50-96h) of deltamethrin (formulation BUTOX®CE25) on the in vivo cardio-respiratory function of Nile tilapia (Oreochromis niloticus), are species of high economic potential. The cardio-respiratory parameters (O2 uptake - V&O2 , respiratory frequency fR, gill ventilation - G V& , ventilatory tidal volume VT, O2 extraction from the ventilatory current EO2, and heart frequency fH) were measured in a group of intact fish (GC), under normoxic conditions, during 24 h. After this period, another group of fish (GE) was exposed to deltamethrin and kept under these conditions for another 24 h period. During these periods the cardio-respiratory variables were continuously monitored. In another series of experiments, a group of non-intoxicated fish (GCH) was exposed to normoxia (PwO2 ~ 140 mmHg) and subsequently submitted to graded hypoxia (PwO2 = 100, 70, 50, 30 and 20 mmHg), while the above cardio-respiratory variables were continuously measured. A fourth group (GEH) was exposed to deltamethrin and submitted to the same hypoxic leves. Just after the exposure to deltamethrin fish presented a reduction in 2 V&O (mLO2.kg-1.h-1) which recovered gradually and reached initial (control) values after 18 h. Meanwhile fR (breaths.min- 1) remained unchanged in response to the toxicant. The G V& (mLH2O.Kg-1.min-1), however, increased significantly in the first 6 h of exposure to deltamethrin, returning to the initial values after 9 h. The G V& increased as a consequence of a proportional enhancement in VT (mLH2O.kg-1.resp-1). Immediately after the toxicant administration, fish presented a significant reduction in fH (bpm) and this bradicardia remained for a period of 12 h, after which this variable returned to the control values. Fish exposed to deltamethrin and submitted to graded hypoxia presented a significant reduction in 2 V&O , while their critical oxygen tension (PcO2) increased in relation to the control group. This indicates impairment in the capacity of oxyregulation of intoxicated fish. Also during graded hypoxia G V& and VT of fish exposed to deltamethrin increased progressively, while fR did not change. The fH was significant lower (bradicardia) in all hypoxic tensions. In conclusion, when Nile tilapia is exposed to sub-lethal concentrations of deltamethrin (formulation BUTOX ®CE25), the cardio-respiratory variables of this species stabilize after about 24 h, indicating a fast recovery to the toxicity of this pesticide. The cardio-respiratory responses to hypoxia, however, are impaired by deltamethrine exposure, suggesting that an adequate aerobic metabolism is important in the detoxification of this pesticide.