scholarly journals Autonomous Systems for the Environmental Characterization of Lagoons

2020 ◽  
Author(s):  
Monica Rivas Casado ◽  
Marco Palma ◽  
Paul Leinster
Keyword(s):  
Autonomous Systems ◽  
Environmental Characterization

scholarly journals Living Benthic Foraminifera from the Surface and Subsurface Sediment Layers Applied to the Environmental Characterization of the Brazilian Continental Slope (SW Atlantic)

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1863
Author(s):  
Luciana Cristina de Carvalho Santa-Rosa ◽  
Sibelle Trevisan Disaró ◽  
Violeta Totah ◽  
Silvia Watanabe ◽  
Ana Tereza Bittencourt Guimarães
Keyword(s):  
Continental Slope ◽  
Benthic Foraminifera ◽  
Subsurface Layer ◽  
Environmental Characterization ◽  
Potiguar Basin ◽  
Middle Slope ◽  
Sw Atlantic ◽  
Sediment Layers ◽  
Lower Slope

Living benthic foraminifera (>63 µm) were studied to characterize the continental slope of the Potiguar Basin (SW Atlantic). Foraminifers from the surface (0–2 cm), subsurface (2–5 cm), and integrated (0–5 cm) sediment layers were analyzed to verify their contribution to environmental characterization. It was also estimated if and which changes occur when the subsurface is added. Sampling stations were distributed in five transects in four isobaths (150, 400, 1000, and 2000 m). Sediment samples were fixed with 4% buffered formaldehyde and stained with Bengal rose. Were recorded 396 species in the surface layer, 228 in the subsurface, and 449 in integrating both layers. This study did not include tubular agglutinated species. The assemblages from 150 m isobath indicated the upper slope, from 400 m indicated the middle slope and the ones from the 2000 m indicated the lower slope. The surface layer’s assemblage at 1000 m isobath was more similar to the middle slope; in contrast, its subsurface layer´s assemblage had more similarity with the lower slope. Rarefaction curves, Permanova, and NMDS routines indicated a high resemblance between surface and integrated layers. Therefore, the first two centimeters were sufficient to characterize this region based on living benthic foraminifera.

scholarly journals STATISTICAL MULTIVARIATE ANALYSIS APPLIED TO ENVIRONMENTAL CHARACTERIZATION OF SOIL IN SEMIARID REGION1

2019 ◽  
Vol 32 (1) ◽  
pp. 200-210
Author(s):  
Antônio Italcy de Oliveira Júnior ◽  
Luiz Alberto Ribeiro Mendonça ◽  
Sávio de Brito Fontenele ◽  
Adriana Oliveira Araújo ◽  
Maria Gorethe de Sousa Lima Brito
Keyword(s):  
Organic Matter Content ◽  
Principal Component ◽  
Matter Content ◽  
Multivariate Statistical ◽  
Statistical Tool ◽  
Environmental Characterization ◽  
Hierarchical Grouping ◽  
Two Factors ◽  
Total Data

ABSTRACT Soil is a dynamic and complex system that requires a considerable number of samples for analysis and research purposes. Using multivariate statistical methods, favorable conditions can be created by analyzing the samples, i.e., structural reduction and simplification of the data. The objective of this study was to use multivariate statistical analysis, including factorial analysis (FA) and hierarchical groupings, for the environmental characterization of soils in semiarid regions, considering anthropic (land use and occupation) and topographic aspects (altitude, moisture, granulometry, PR, and organic-matter content). As a case study, the São José Hydrographic Microbasin, which is located in the Cariri region of Ceará, was considered. An FA was performed using the principal component method, with normalized varimax rotation. In hierarchical grouping analysis, the “farthest neighbor” method was used as the hierarchical criterion for grouping, with the measure of dissimilarity given by the “square Euclidean distance.” The FA indicated that two factors explain 75.76% of the total data variance. In the analysis of hierarchical groupings, the samples were agglomerated in three groups with similar characteristics: one with samples collected in an area of the preserved forest and two with samples collected in areas with more anthropized soils. This indicates that the statistical tool used showed sensitivity to distinguish the most conserved soils and soils with different levels of anthropization.

scholarly journals Stability of Nonlinear Autonomous Quadratic Discrete Systems in the Critical Case

2010 ◽  
Vol 2010 ◽  
pp. 1-23 ◽  
Author(s):  
Josef Diblík ◽  
Denys Ya. Khusainov ◽  
Irina V. Grytsay ◽  
Zdenĕk Šmarda
Keyword(s):  
Lyapunov Functions ◽  
Critical Case ◽  
Autonomous Systems ◽  
Discrete Systems ◽  
Simple Eigenvalue ◽  
Discrete Equations ◽  
The Matrix ◽  
The Stability ◽  
Important Characterization

Many processes are mathematically simulated by systems of discrete equations with quadratic right-hand sides. Their stability is thought of as a very important characterization of the process. In this paper, the method of Lyapunov functions is used to derive classes of stable quadratic discrete autonomous systems in a critical case in the presence of a simple eigenvalueλ=1of the matrix of linear terms. In addition to the stability investigation, we also estimate stability domains.

Use of AIS data for the environmental characterization of world cruise ship traffic

2019 ◽  
Vol 14 (6) ◽  
pp. 465-474
Author(s):  
Isaías Vicente-Cera ◽  
Asunción Acevedo-Merino ◽  
Juan Antonio López-Ramírez ◽  
Enrique Nebot
Keyword(s):  
Cruise Ship ◽  
Ship Traffic ◽  
Environmental Characterization

Characterization of Mechanical Properties in Multifunctional Structural-Energy Storage Nanocomposites for Lightweight Micro Autonomous Systems

2011 ◽  
Author(s):  
Daniel P. Cole ◽  
Monica Rivera ◽  
Mark Bundy
Keyword(s):  
Energy Storage ◽  
Electrode Materials ◽  
Mechanical Performance ◽  
Autonomous Systems ◽  
Deposition Process ◽  
Mechanical Tests ◽  
Energy Storage Materials ◽  
Structural Components ◽  
Storage Materials

A major concern in the design of micro-robotic systems is an on-board energy supply capable of providing the necessary power requirements, while limiting the volume/mass burden to the vehicle. The conventional solution to this design problem is to maximize the energy density of the on-board power supply. An alternative approach is to replace single-function structural components with multifunctional structural-energy storage materials. The mass and volume savings associated with the material substitution could potentially result in improved endurance and/or increased payload (e.g. video camera, microphone, chemical/biological sensors). In this study, carbon nanotube (CNT) based composites were used to fabricate structural-energy storage materials. Specifically, supercapacitor electrodes were constructed from paper covered with CNT ink and from polymer matrices infused with aligned CNT forests. The composites were subject to bulk mechanical tests in order to characterize their suitability as structural components in micro-autonomous systems. Tensile tests on the paper composites show directional and strain rate dependencies. The CNT-ink deposition process was found to degrade the elastic modulus of the paper by approximately 50%, although the tensile strength of the materials was largely unaffected. Preliminary electrical characterization of the CNT-coated electrode materials indicate that the nanomaterials potentially reach a percolation threshold after multiple depositions, resulting in a conductive surface network. Initial results indicate that improvements in the electrical properties of the CNT paper electrodes are met with reductions in the mechanical performance of the composites.

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