Simulação do impacto das atividades florestais na fragilidade potencial em plantios de pinus.

Este trabalho, realizado em uma área com povoamento de Pinus taeda, teve por objetivo simular e mapear a influência do valor de impacto das atividades florestais na fragilidade potencial. Variáveis do solo, de declividade do terreno, valor de impacto e de cobertura vegetal foram utilizadas para gerar os mapas. Os resultados expressos pelo modelo adotado mostraram que as áreas mais frágeis apresentam em sua maioria declividades superiores a 75 % e textura que variam de arenosa a média, e as áreas menos frágeis apresentam predominantemente relevo plano (até 3 %) e textura argilosa. Quando simulado o impacto das atividades florestais sobre esse ambiente, verificou-se que na maior parte da área (78 %) todas as atividades florestais podem ser realizadas sem influência na degradação do meio ambiente e para algumas áreas (11 %) o ambiente foi considerado menos frágil, em razão da presença de cobertura vegetal

Unidades de manejo para Pinus taeda L. com base na análise de agrupamento.

Seção: Silvicultura e Produção de Biomassa

Examination on Time-Dependent Soil Models in One-Dimensional Consolidation

This paper reviews the performance of two time-dependent constitutive models in predictions of one-dimensional consolidation. The Soft-Soil Creep model [1] is an example of an elastic-viscoplastic formulation that incorporates a time-dependent state variable to estimate viscoplastic deformation. We show that the SSC model is equivalent to the isotache formulation proposed by Imai [2], as both are based on a unique relationship between stress, void ratio and the viscoplastic component of void ratio rate. Simulations of 1-D consolidation confirm that both models represent Hypothesis B behavior, where the axial strain at the End of Primary (EOP) consolidation is dependent on the depth of the clay layer. The effects of specimen thickness and the phenomenon of pore pressure increase at the start of consolidation are discussed in detail. Our interpretation highlights the importance of assumptions regarding the initial strain rate on the behavior observed at different scales under a given applied increment of loading

Cable Median Barrier Failure Analysis and Remediation Phase II

Cable median barrier crashes from a total of 12 states were analyzed. Crash data included scene diagrams, photographs, and field measurements, crash narratives, although the availability of data in each crash varied. Major contributors to penetration crash propensity were identified: diving underride, in which the front end of the vehicle dropped below the bottom cable; prying, in which the vehicle profile caused cable separation or lifting; override; bouncing override, in which the vehicle rebounded after contact with the back slope and bounced over the top of the barrier; system failure, in which one component failure or design failure prevented the cables from adequately engaging the vehicle; and large vehicle crashes, such as tractor trailers, buses, and single-unit trucks into TL-3 systems. Major contributors to rollover were identified: steep median slopes, in which the slope caused unstable bouncing or abrupt changes in slope profiles acted as trip points for the tires; broadside skid, in which the vehicle was skidding with a sideslip angle of nearly 90 degrees prior to contact with the barrier; contact with post, in which the post acted as a trip point; and other factors such as towing trailer units, median anomalies, or with large vehicles such as tractor-trailers, buses, or motor homes. Recommended improvements to cable median barrier systems included: minimum top cable height of 35 in. (890 mm); maximum top cable height of 15 in. (381 mm); minimum of 4 cables supported by posts; higher lateral cable-to-post attachment strength at bottom and lower strength at top; low strong-axis strength post sections; and to eliminate cable entrapment in a vertical slot in the post when initial cable contact occurs at a post location. A summary of factors and how they contributed to penetration, rollover, and severe crash probability is shown in Table 1

Levantamento detalhado de solos de áreas de produção florestal no Município de Ponte Serrada, oeste catarinense.

Introdução; Material; Levantamento de solos; Metodologia de trabalho; Resultados do mapeamento de solos; Legenda do mapeamento de solos; Classes de solo (definidas conforme Embrapa, 2006); Latossolos Brunos (LB); Nitossolos Brunos (LB); Cambissolos Húmicos (CH); Neossolos Litólicos (RL), Neossolos Regolíticos (RR) e afloramentos de rocha (AR); Gleissolos Melânicos; Considerações finais; Referências; Anexo - mapa detalhado de solo da Fazenda Cristo Rei, Celulose Irani S.A.bitstream/item/121209/1/Doc.-249-Joao-Bosco-versao-final.pd