847 research outputs found
AVALIAÇÃO DE REGISTROS SEDIMENTARES NA ÁREA DA ENCOSTA DA FACE LESTE DO DOMO DE ITABAIANA-SE: RESULTADOS PRELIMINARES
O Quaternário é reconhecido por variações das condições climáticas que deixaram na paisagem marcas dessas oscilações. O trabalho objetivou reconhecer características dos depósitos e estruturas presentes nas seções. A encosta encontra-se numa área susceptível as mudanças na sua estrutura, remodelando a forma do relevo, onde foram encontradas depósitos referentes a eventos de grande magnitude ou de alta torrencialidade capaz de remobilizar mantos de alteração em forma de fluxos em curtos
MONITORAMENTO DE PROCESSOS EROSIVOS EM UMA ENCOSTA DA BORDA LESTE NO DOMO DE ITABAIANA/SE
A região do Domo de Itabaiana localizada no agreste sergipano se apresenta como um importante compartimento morfoestrutural, de geodiversidade bem particularizada sob condições de marcante metamorfismo regional, neste são evidenciadas dinâmicas diferenciadas da Paisagem geomorfológica. Dá analise realizada emerge a relação pedogênese-morfogênese, onde hoje na área ocorre o predomínio da morfogênese
Reduced order models for control of fluids using the Eigensystem Realization Algorithm
In feedback flow control, one of the challenges is to develop mathematical
models that describe the fluid physics relevant to the task at hand, while
neglecting irrelevant details of the flow in order to remain computationally
tractable. A number of techniques are presently used to develop such
reduced-order models, such as proper orthogonal decomposition (POD), and
approximate snapshot-based balanced truncation, also known as balanced POD.
Each method has its strengths and weaknesses: for instance, POD models can
behave unpredictably and perform poorly, but they can be computed directly from
experimental data; approximate balanced truncation often produces vastly
superior models to POD, but requires data from adjoint simulations, and thus
cannot be applied to experimental data.
In this paper, we show that using the Eigensystem Realization Algorithm (ERA)
\citep{JuPa-85}, one can theoretically obtain exactly the same reduced order
models as by balanced POD. Moreover, the models can be obtained directly from
experimental data, without the use of adjoint information. The algorithm can
also substantially improve computational efficiency when forming reduced-order
models from simulation data. If adjoint information is available, then balanced
POD has some advantages over ERA: for instance, it produces modes that are
useful for multiple purposes, and the method has been generalized to unstable
systems. We also present a modified ERA procedure that produces modes without
adjoint information, but for this procedure, the resulting models are not
balanced, and do not perform as well in examples. We present a detailed
comparison of the methods, and illustrate them on an example of the flow past
an inclined flat plate at a low Reynolds number.Comment: 22 pages, 7 figure
On the evaluation of soil erosion models:Are we doing enough?
As any model of real-world phenomena, soil erosion models must be tested against empirical evidence to have their performance evaluated. This is critical to develop knowledge and confidence in model predictions. However, evaluating soil erosion models is complicated due to the uncertainties involved in the estimation of model parameters and measurements of system responses. Here, we undertake a term co-occurrence analysis to investigate how model evaluation is approached in soil erosion research. The analysis illustrates how model testing is often neglected, and how model evaluation topics are segregated from current research interests. We perform a meta-analysis of model performance to understand the mechanisms that influence model predictive accuracy. Results indicate that different models do not systematically outperform each other, and that calibration seems to be the main mechanism of model improvement. We review how soil erosion models have been evaluated at different temporal and spatial scales, focusing on the methods, assumptions, and data used for model testing. We discuss the implications of uncertainty and equifinality in soil erosion models, and implement a case study of uncertainty assessment that enables models to be tested as hypotheses. A comment on the way forward for the evaluation of erosion models is presented, discussing philosophical aspects of hypothesis testing in environmental modelling. We refute the notion that soil erosion models can be validated, and emphasize the necessity of defining fit-for-purpose tests, based on multiple sources of data, that allow for a broad investigation of model usefulness and consistency
Estudo do Efeito da Adição de Pp Reciclado nas Propriedades Mecânicas e de Escoamento De Misturas De Pp/Epdm
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Quantitative plant proteomics using hydroponic isotope labeling of entire plants (HILEP)
Measurement of the cosmic microwave background polarization lensing power spectrum from two years of POLARBEAR data
We present a measurement of the gravitational lensing deflection power spectrum reconstructed with two seasons of cosmic microwave background polarization data from the POLARBEAR experiment. Observations were taken at 150 GHz from 2012 to 2014 and surveyed three patches of sky totaling 30 square degrees. We test the consistency of the lensing spectrum with a cold dark matter cosmology and reject the no-lensing hypothesis at a confidence of 10.9σ, including statistical and systematic uncertainties. We observe a value of AL = 1.33 ± 0.32 (statistical) ±0.02 (systematic) ±0.07 (foreground) using all polarization lensing estimators, which corresponds to a 24% accurate measurement of the lensing amplitude. Compared to the analysis of the first- year data, we have improved the breadth of both the suite of null tests and the error terms included in the estimation of systematic contamination
Natural insecticide based-leaves extract of Piper aduncum (Piperaceae) in the control of stink bug brown soybean
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